Effect of acid detergent fiber in hydrothermally pretreated sewage sludge on anaerobic digestion process

NASA Astrophysics Data System (ADS)

Takasaki, Rikiya; Yuan, Lee Chang; Kamahara, Hirotsugu; Atsuta, Youichi; Daimon, Hiroyuki

2017-10-01

Hydrothermal treatment is one of the pre-treatment method for anaerobic digestion. The application of hydrothermal treatment to sewage sludge of wastewater treatment plant has been succeeded to enhance the biogas production. The purpose of this study is to quantitatively clarify the effect of hydrothermal treatment on anaerobic digestion process focusing on acid detergent fiber (ADF) in sewage sludge, which is low biodegradability. The hydrothermal treatment experiment was carried out for 15 minutes between 160 °C and 200 °C respectively. The ADF content was decreased after hydrothermal treatment compared with untreated sludge. However, ADF content was increased when raising the treatment temperature from 160 °C to 200 °C. During batch anaerobic digestion experiment, untreated and treated sludge were examined for 10 days under 38 °C, and all samples were fed once based on volatile solids of samples. From batch anaerobic digestion experiment, as ADF content in sewage sludge increased, the total biogas production decreased. It was found that ADF content in sewage sludge influence on anaerobic digestion. Therefore, ADF could be one of the indicator to evaluate the effect of hydrothermal treatment to sewage sludge on anaerobic digestion.

Removal of Triclocarban and Triclosan during Municipal Biosolid Production

PubMed Central

Ogunyoku, Temitope A.; Young, Thomas M.

2014-01-01

The antimicrobial compounds triclosan (TCS) and triclocarban (TCC) accumulate in sludges produced during municipal wastewater treatment and persist through sludge treatment processes into finished biosolids. The objective of this research was to determine the extent to which conventional sludge processing systems such as aerobic digestion, anaerobic digestion, and lime stabilization were able to remove TCC and TCS. Sludge and biosolid samples were collected from 10 municipal wastewater treatment plants in the United States. The concentrations of TCC and TCS in sludge and biosolid samples were determined via heated solvent extraction and analysis with liquid chromatography electrospray ionization mass spectrometry. Dry weight concentrations of TCC and TCS frequently were higher in finished biosolids than in the source sludges because of sludge mass reduction during digestion. The removal of TCC and TCS in municipal biosolid processing systems was determined from the measured concentration change after correcting for reductions in solid mass during sludge treatment. Removal in the digester systems ranged from 15 – 68 % for TCC and 20 – 75 % for TCS. Increased solid retention times during sludge treatment operations were correlated with higher removals of TCC and TCS. Apparent first order degradation rates for TCC ranged from 0.015–0.08 1/d and for TCS were between 0.003–0.15 1/d. PMID:24734467

Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge.

PubMed

Mondal, Tania; Rouch, Duncan A; Thurbon, Nerida; Smith, Stephen R; Deighton, Margaret A

2015-06-01

Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, γ-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures.

Analysis of Combustion Process of Sewage Sludge in Reference to Coals and Biomass

NASA Astrophysics Data System (ADS)

Środa, Katarzyna; Kijo-Kleczkowska, Agnieszka

2016-06-01

Production of sewage sludge is an inseparable part of the treatment process. The chemical and sanitary composition of sewage sludge flowing into the treatment plant is a very important factor determining the further use of the final product obtained in these plants. The sewage sludge is characterized by heterogeneity and multi-components properties, because they have characteristics of the classical and fertilizer wastes and energetic fuels. The thermal utilization of sewage sludge is necessary due to the unfavorable sanitary characteristics and the addition of the industrial sewage. This method ensures use of sewage sludge energy and return of expenditure incurred for the treatment of these wastes and their disposal. Sewage sludge should be analyzed in relation to conventional fuels (coals and biomass). They must comply with the applicable requirements, for example by an appropriate degree of dehydration, which guarantee the stable and efficient combustion. This paper takes the issue of the combustion process of the different sewage sludge and their comparison of the coal and biomass fuels.

Enhancement of the sludge disintegration and nutrients release by a treatment with potassium ferrate combined with an ultrasonic process.

PubMed

Li, Wei; Yu, Najiaowa; Liu, Qian; Li, Yiran; Ren, Nanqi; Xing, Defeng

2018-09-01

Sludge disintegration by ultrasound is a promising sludge treatment method. In order to enhance the efficiency of the sludge reduction and hydrolysis, potassium ferrate (K 2 FeO 4 ) (PF) was used. A novel method was developed to improve the sludge disintegration-sludge pretreatment by using PF in combination with an ultrasonic treatment (PF + ULT). After a short-term PF + ULT treatment, 17.23% of the volatile suspended solids (VSS) were reduced after a 900-min reaction time, which is 61.3% higher than the VSS reduction for the raw sludge. The supernatant soluble chemical oxygen demand (SCOD), total nitrogen (TN), volatile fatty acids (VFAs), soluble protein and polysaccharides increased by 522.5%, 1029.4%, 878.4%, 2996.6% and 801.9%, respectively. The constituent parts of the dissolved organic matter of the sludge products were released efficiently, which demonstrated the positive effect caused by the PF + ULT. The enhanced sludge disintegration process further alleviates environmental risk and offers a more efficient and convenient method for utilizing sludge. Copyright © 2018 Elsevier B.V. All rights reserved.

An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation.

PubMed

Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

2013-11-15

Lab-scale High Efficiency Digestion (HED) systems containing a Mesophilic Anaerobic Reactor (MAR), Thermophilic Aerobic Reactor (TAR), liquid/solid separation unit, and thermal-alkaline treatment were developed to evaluate the efficiencies of sludge reduction and methane production. The HED process was divided into three phases to examine the influence of sludge pretreatment and pretreated sludge recirculation using TCOD and VSS reduction, COD solubilization, and methane production. The VSS removal with a solid/liquid separation unit, sludge recirculation, and thermal-alkaline treatment drastically increased up to 95% compared to the feed concentration. In addition, the results of COD solubilization and VSS/TSS showed that the solubilization of cells and organic matters by the thermal-alkaline treatment was highly increased, which was also consistent with the SEM images. In particular, the methane production rate increased 24-fold when the feed sludge and recirculated sludge were pretreated together. Collectively, the HED experiments performed with sludge recirculation and thermal-alkaline treatment demonstrated that the HED systems can be successfully employed for highly efficient sewage sludge reduction and methane gas production. Copyright © 2013 Elsevier Ltd. All rights reserved.

40 CFR 503.6 - Exclusions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... treatment of domestic sewage in a treatment works. (i) Drinking water treatment sludge. This part does not... DISPOSAL OF SEWAGE SLUDGE General Provisions § 503.6 Exclusions. (a) Treatment processes. This part does... requirements for the use or disposal of sludge generated at an industrial facility during the treatment of...

Up-to-date modification of the anaerobic sludge digestion process introducing a separate sludge digestion mode.

PubMed

Sato, K; Ochi, S; Mizuochi, M

2001-01-01

Sewage treatment plants in Japan are subjected to advanced treatment to remove nutrients and hence control eutrophication problems in lakes and bays. This paper discusses the advantages and disadvantages of the separate digestion treatment mode for sludge generated from advanced wastewater treatment. In the separate digestion only primary sludge is digested and the excess activated sludge is directly dewatered. Separate digestion can reduce the return load of nutrients to approximately one third, and has major potential for the beneficial use of sludge.

Drying characteristics of electro-osmosis dewatered sludge.

PubMed

Ma, Degang; Qian, Jingjing; Zhu, Hongmin; Zhai, Jun

2016-12-01

Electro-osmotic dewatering (EDW) is one of the effective deeply dewatering technologies that is suitable for treating sludge with 55-80% of moisture content. Regarding EDW as the pre-treatment process of drying or incinerating, this article investigated the drying characteristics of electro-osmosis-dewatered sludge, including shear stress test, drying curves analysis, model analysis, and energy balance calculation. After EDW pre-treatment, sludge adhesion was reduced. The sludge drying rate was higher compared to the non-pre-treated sludge, especially under high temperatures (80-120°C). In addition, it is better to place the sludge cake with cathode surface facing upward for improving the drying rate. An adjusted model based on the Logarithmic model could better describe the EDW sludge drying process. Using the energy balance calculation, EDW can save the energy consumed in the process of sludge incineration and electricity generation and enable the system to run without extra energy input.

Biosolids accumulation and biodegradation of domestic wastewater treatment plant sludge by developed liquid state bioconversion process using a batch fermenter.

PubMed

Alam, Md Zahangir; Fakhru'l-Razi, A; Molla, Abul H

2003-09-01

The biosolids accumulation and biodegradation of domestic wastewater treatment plant (DWTP) sludge by filamentous fungi have been investigated in a batch fermenter. The filamentous fungi Aspergillus niger and Penicillium corylophilum isolated from wastewater and DWTP sludge was used to evaluate the treatment performance. The optimized mixed inoculum (A. niger and P. corylophilum) and developed process conditions (co-substrate and its concentration, temperature, initial pH, inoculum size, and aeration and agitation rate) were incorporated to accelerate the DWTP sludge treatment process. The results showed that microbial treatment of higher strength of DWTP sludge (4% w/w of TSS) was highly influenced by the liquid state bioconversion (LSB) process. In developed bioconversion processes, 93.8 g/kg of biosolids was enriched with fungal biomass protein of 30 g/kg. Enrichment of nutrients such as nitrogen (N), phosphorous (P), potassium (K) in biosolids was recorded in 6.2% (w/w), 3.1% (w/w) and 0.15% (w/w) from its initial values of 4.8% (w/w), 2.0% (w/w) and 0.08% (w/w) respectively after 10 days of fungal treatment. The biodegradation results revealed that 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of COD in treated DWTP sludge supernatant were removed after 8 days of microbial treatment. The specific resistance to filtration (SRF) in treated sludge (1.4x10(12) m/kg) was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation compared to untreated sample (85x10(12) m/kg).

DEMONSTRATION BULLETIN: THE BASIC EXTRACTIVE SLUDGE TREATMENT (B.E.S.T.) RESOURCES CONSERVATION COMPANY (RCC)

EPA Science Inventory

The Basic Extractive Sludge Treatment (B.E.S.T.®) process is a solvent extraction system that separates organic contaminants from sludges, soils, and sediments. The primary distinguishing feature of the process is the extraction agent, triethylamine. The key to the success of tri...

Impact of initial biodegradability on sludge anaerobic digestion enhancement by thermal pretreatment.

PubMed

Carrère, Hélène; Bougrier, Claire; Castets, Delphine; Delgenès, Jean Philippe

2008-11-01

Thermal treatments with temperature ranging from 60 to 210 degrees C were applied to 6 waste-activated sludge samples originating from high or medium load, extended aeration wastewater treatment processes that treated different wastewaters (urban, urban and industrial or slaughterhouse). COD sludge solubilisation was linearly correlated with the treatment temperature on the whole temperature range and independently of the sludge samples. Sludge batch mesophilic biodegradability increased with treatment temperature up to 190 degrees C. In this temperature range, biodegradability enhancement or methane production increase by thermal hydrolysis was shown to be a function of sludge COD solubilisation but also of sludge initial biodegradability. The lower the initial biodegradability means the higher efficiency of thermal treatment.

A modified oxic-settling-anaerobic activated sludge process using gravity thickening for excess sludge reduction

NASA Astrophysics Data System (ADS)

Wang, Jun; Li, Shi-Yu; Jiang, Feng; Wu, Ke; Liu, Guang-Li; Lu, Hui; Chen, Guang-Hao

2015-09-01

Oxic-settling-anaerobic process (OSA) was known as a cost-effective way to reduce the excess sludge production with simple upgrade of conventional activated sludge process (CAS). A low oxidation-reduction potential (ORP) level was the key factor to sludge decay and lysis in the sludge holding tank of the OSA process. However, the ORP control with nitrogen purge or chemical dosing in the OSA process would induce extra expense and complicate the operation. Hence, in this study, a sludge holding tank using gravity thickening was applied to OSA process to reduce the excess sludge production without any ORP control. Results showed that the modified OSA process not only reduced the excess sludge production effectively but also improved the sludge settleability without affected the treatment capacity. The reduction of the excess sludge production in the modified OSA process resulted from interactions among lots of factors. The key element of the process was the gravity thickening sludge holding tank.

Priority and emerging pollutants in sewage sludge and fate during sludge treatment.

PubMed

Mailler, R; Gasperi, J; Chebbo, G; Rocher, V

2014-07-01

This paper aims at characterizing the quality of different treated sludges from Paris conurbation in terms of micropollutants and assessing their fate during different sludge treatment processes (STP). To achieve this, a large panel of priority and emerging pollutants (n=117) have been monitored in different STPs from Parisian wastewater treatment plants including anaerobic digestion, thermal drying, centrifugation and a sludge cake production unit. Considering the quality of treated sludges, comparable micropollutant patterns are found for the different sludges investigated (in mg/kg DM - dry matter). 35 compounds were detected in treated sludges. Some compounds (metals, organotins, alkylphenols, DEHP) are found in every kinds of sludge while pesticides or VOCs are never detected. Sludge cake is the most contaminated sludge, resulting from concentration phenomenon during different treatments. As regards treatments, both centrifugation and thermal drying have broadly no important impact on sludge contamination for metals and organic compounds, even if a slight removal seems to be possible with thermal drying for several compounds by abiotic transfers. Three different behaviors can be highlighted in anaerobic digestion: (i) no removal (metals), (ii) removal following dry matter (DM) elimination (organotins and NP) and iii) removal higher than DM (alkylphenols - except NP - BDE 209 and DEHP). Thus, this process allows a clear removal of biodegradable micropollutants which could be potentially significantly improved by increasing DM removal through operational parameters modifications (retention time, temperature, pre-treatment, etc.). Copyright © 2014 Elsevier Ltd. All rights reserved.

Hybrid life-cycle environmental and cost inventory of sewage sludge treatment and end-use scenarios: a case study from China.

PubMed

Murray, Ashley; Horvath, Arpad; Nelson, Kara L

2008-05-01

Sewage sludge management poses environmental, economic, and political challenges for wastewater treatment plants and municipalities around the globe. To facilitate more informed and sustainable decision making, this study used life-cycle inventory (LCI) to expand upon previous process-based LCIs of sewage sludge treatmenttechnologies. Additionally, the study evaluated an array of productive end-use options for treated sewage sludge, such as fertilizer and as an input into construction materials, to determine how the sustainability of traditional manufacturing processes changes with sludge as a replacement for other raw inputs. The inclusion of the life-cycle of necessary inputs (such as lime) used in sludge treatment significantly impacts the sustainability profiles of different treatment and end-use schemes. Overall, anaerobic digestion is generally the optimal treatment technology whereas incineration, particularly if coal-fired, is the most environmentally and economically costly. With respect to sludge end use, offsets are greatest for the use of sludge as fertilizer, but all of the productive uses of sludge can improve the sustainability of conventional manufacturing practices. The results are intended to help inform and guide decisions about sludge handling for existing wastewater treatment plants and those that are still in the planning phase in cities around the world. Although additional factors must be considered when selecting a sludge treatment and end-use scheme, this study highlights how a systems approach to planning can contribute significantly to improving overall environmental sustainability.

Two strategies for phosphorus removal from reject water of municipal wastewater treatment plant using alum sludge.

PubMed

Yang, Y; Zhao, Y Q; Babatunde, A O; Kearney, P

2009-01-01

In view of the well recognized need of reject water treatment in MWWTP (municipal wastewater treatment plant), this paper outlines two strategies for P removal from reject water using alum sludge, which is produced as by-product in drinking water treatment plant when aluminium sulphate is used for flocculating raw waters. One strategy is the use of the alum sludge in liquid form for co-conditioning and dewatering with the anaerobically digested activated sludge in MWWTP. The other strategy involves the use of the dewatered alum sludge cakes in a fixed bed for P immobilization from the reject water that refers to the mixture of the supernatant of the sludge thickening process and the supernatant of the anaerobically digested sludge. Experimental trials have demonstrated that the alum sludge can efficiently reduce P level in reject water. The co-conditioning strategy could reduce P from 597-675 mg P/L to 0.14-3.20 mg P/L in the supernatant of the sewage sludge while the organic polymer dosage for the conditioning of the mixed sludges would also be significantly reduced. The second strategy of reject water filtration with alum sludge bed has shown a good performance of P reduction. The alum sludge has P-adsorption capacity of 31 mg-P/g-sludge, which was tested under filtration velocity of 1.0 m/h. The two strategies highlight the beneficial utilization of alum sludge in wastewater treatment process in MWWTP, thus converting the alum sludge as a useful material, rather than a waste for landfill.

Improving the sludge disintegration efficiency of sonication by combining with alkalization and thermal pre-treatment methods.

PubMed

Şahinkaya, S; Sevimli, M F; Aygün, A

2012-01-01

One of the most serious problems encountered in biological wastewater treatment processes is the production of waste activated sludge (WAS). Sonication, which is an energy-intensive process, is the most powerful sludge pre-treatment method. Due to lack of information about the combined pre-treatment methods of sonication, the combined pre-treatment methods were investigated and it was aimed to improve the disintegration efficiency of sonication by combining sonication with alkalization and thermal pre-treatment methods in this study. The process performances were evaluated based on the quantities of increases in soluble chemical oxygen demand (COD), protein and carbohydrate. The releases of soluble COD, carbohydrate and protein by the combined methods were higher than those by sonication, alkalization and thermal pre-treatment alone. Degrees of sludge disintegration in various options of sonication were in the following descending order: sono-alkalization > sono-thermal pre-treatment > sonication. Therefore, it was determined that combining sonication with alkalization significantly improved the sludge disintegration and decreased the required energy to reach the same yield by sonication. In addition, effects on sludge settleability and dewaterability and kinetic mathematical modelling of pre-treatment performances of these methods were investigated. It was proven that the proposed model accurately predicted the efficiencies of ultrasonic pre-treatment methods.

Modelling the structure of sludge aggregates

PubMed Central

Smoczyński, Lech; Ratnaweera, Harsha; Kosobucka, Marta; Smoczyński, Michał; Kalinowski, Sławomir; Kvaal, Knut

2016-01-01

ABSTRACT The structure of sludge is closely associated with the process of wastewater treatment. Synthetic dyestuff wastewater and sewage were coagulated using the PAX and PIX methods, and electro-coagulated on aluminium electrodes. The processes of wastewater treatment were supported with an organic polymer. The images of surface structures of the investigated sludge were obtained using scanning electron microscopy (SEM). The software image analysis permitted obtaining plots log A vs. log P, wherein A is the surface area and P is the perimeter of the object, for individual objects comprised in the structure of the sludge. The resulting database confirmed the ‘self-similarity’ of the structural objects in the studied groups of sludge, which enabled calculating their fractal dimension and proposing models for these objects. A quantitative description of the sludge aggregates permitted proposing a mechanism of the processes responsible for their formation. In the paper, also, the impact of the structure of the investigated sludge on the process of sedimentation, and dehydration of the thickened sludge after sedimentation, was discussed. PMID:26549812

Technologies for reducing sludge production in wastewater treatment plants: State of the art.

PubMed

Wang, Qilin; Wei, Wei; Gong, Yanyan; Yu, Qiming; Li, Qin; Sun, Jing; Yuan, Zhiguo

2017-06-01

This review presents the state-of-the-art sludge reduction technologies applied in both wastewater and sludge treatment lines. They include chemical, mechanical, thermal, electrical treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater treatment line, and physical, chemical and biological pretreatment in sludge treatment line. Emphasis was put on their effect on sludge reduction performance, with 10% sludge reduction to zero sludge production in wastewater treatment line and enhanced TS (total solids) or volatile solids removal of 5-40% in sludge treatment line. Free nitrous acid (FNA) technology seems good in wastewater treatment line but it is only under the lab-scale trial. In sludge treatment line, thermal, ultrasonic (<4400kJ/kg TS), FNA pretreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal pretreatment and TPAD are superior to other pretreatment technologies when pathogen inactivation is required. The new wastewater treatment processes including SANI®, high-rate activated sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce sludge production. In the future, an effort should be put on the effect of sludge reduction technologies on the removal of organic micropollutants and heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

PubMed Central

Gebreeyessus, Getachew D.; Jenicek, Pavel

2016-01-01

During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize the connection between the two systems. In addition, many other relevant AD process parameters, including sludge rheology, which need to be addressed, are also reviewed and presented. PMID:28952577

Combined System of Activated Sludge and Ozonation for the Treatment of Kraft E1 Effluent

PubMed Central

Assalin, Marcia Regina; dos Santos Almeida, Edna; Durán, Nelson

2009-01-01

The treatment of paper mill effluent for COD, TOC, total phenols and color removal was investigated using combined activated sludge-ozonation processes and single processes. The combined activated sludge-O3/pH 10 treatment was able to remove around 80% of COD, TOC and color from Kraft E1 effluent. For the total phenols, the efficiency removal was around 70%. The ozonation post treatment carried out at pH 8.3 also showed better results than the single process. The COD, TOC, color and total phenols removal efficiency obtained were 75.5, 59.1, 77 and 52.3%, respectively. The difference in the concentrations of free radical produced by activated sludge-O3/pH 10 and activated sludge-O3/pH 8.3 affected mainly the TOC and total phenol removal values. PMID:19440438

Full scale implementation of the nutrient limited BAS process at Södra Cell Värö.

PubMed

Malmqvist, A; Berggren, B; Sjölin, C; Welander, T; Heuts, L; Fransén, A; Ling, D

2004-01-01

A combination of the suspended carrier biofilm process and the activated sludge process (biofilm-activated sludge--BAS) has been shown to be very successful for the treatment of different types of pulp and paper mill effluents. The robust biofilm pre-treatment in combination with activated sludge results in a stable, compact and highly efficient process. Recent findings have shown that nutrient limited operation of the biofilm process greatly improves the sludge characteristics in the following activated sludge stage, while minimising sludge production and effluent discharge of nutrients. The nutrient limited BAS process was implemented at full scale at the Södra Cell Värö kraft mill and taken into operation in July 2002. After start-up and optimisation over about 5 months, the process meets all effluent discharge limits. The removal of COD is close to 70% and the removal of EDTA greater than 90%. Typical effluent concentrations of suspended solids and nutrients during stable operations have been 20-30 mg/L TSS, 0.3-0.5 mg/L phosphorus and 3-5 mg/L nitrogen. The sludge production was 0.09 kgSS/kg COD removed and the sludge volume index was 50-100 mL/g.

Heat Treatment. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Filer, Herb; Broste, Dale

This lesson was developed for a course in sludge treatment and disposal. The lesson describes the Porteous heat treatment method of sludge conditioning and compares that system to the Zimpro wet air oxidation process. The theory of heat treatment, system of components and functions, and concepts of operation are addressed in the lesson. The…

Operating aerobic wastewater treatment at very short sludge ages enables treatment and energy recovery through anaerobic sludge digestion.

PubMed

Ge, Huoqing; Batstone, Damien J; Keller, Jurg

2013-11-01

Conventional abattoir wastewater treatment processes for carbon and nutrient removal are typically designed and operated with a long sludge retention time (SRT) of 10-20 days, with a relatively high energy demand and physical footprint. The process also generates a considerable amount of waste activated sludge that is not easily degradable due to the long SRT. In this study, an innovative high-rate sequencing batch reactor (SBR) based wastewater treatment process with short SRT and hydraulic retention time (HRT) is developed and characterised. The high-rate SBR process was shown to be most effective with SRT of 2-3 days and HRT of 0.5-1 day, achieving >80% reduction in chemical oxygen demand (COD) and phosphorus and approximately 55% nitrogen removal. A majority of carbon removal (70-80%) was achieved by biomass assimilation and/or accumulation, rather than oxidation. Anaerobic degradability of the sludge generated in the high-rate SBR process was strongly linked to SRT, with measured degradability extent being 85% (2 days SRT), 73% (3 days), and 63% (4 days), but it was not influenced by digestion temperature. However, the rate of degradation for 3 and 4 days SRT sludge was increased by 45% at thermophilic conditions compared to mesophilic conditions. Overall, the treatment process provides a very compact and energy efficient treatment option for highly degradable wastewaters such as meat and food processing, with a substantial space reduction by using smaller reactors and a considerable net energy output through the reduced aerobic oxidation and concurrent increased methane production potential through the efficient sludge digestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Proof of concept for a new energy-positive wastewater treatment scheme.

PubMed

Remy, C; Boulestreau, M; Lesjean, B

2014-01-01

For improved exploitation of the energy content present in the organic matter of raw sewage, an innovative concept for treatment of municipal wastewater is tested in pilot trials and assessed in energy balance and operational costs. The concept is based on a maximum extraction of organic matter into the sludge via coagulation, flocculation and microsieving (100 μm mesh size) to increase the energy recovery in anaerobic sludge digestion and decrease aeration demand for carbon mineralisation. Pilot trials with real wastewater yield an extraction of 70-80% of total chemical oxygen demand into the sludge while dosing 15-20 mg/L Al and 5-7 mg/L polymer with stable operation of the microsieve and effluent limits below 2-3 mg/L total phosphorus. Anaerobic digestion of the microsieve sludge results in high biogas yields of 600 NL/kg organic dry matter input (oDMin) compared to 430 NL/kg oDMin for mixed sludge from a conventional activated sludge process. The overall energy balance for a 100,000 population equivalent (PE) treatment plant (including biofilter for post-treatment with full nitrification and denitrification with external carbon source) shows that the new concept is an energy-positive treatment process with comparable effluent quality than conventional processes, even when including energy demand for chemicals production. Estimated operating costs for electricity and chemicals are in the same range for conventional activated sludge processes and the new concept.

Membrane thickening aerobic digestion processes.

PubMed

Woo, Bryen

2014-01-01

Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent, therefore much consideration is required when designing a solids handling process. A membrane thickening aerobic digestion process integrates a controlled aerobic digestion process with pre-thickening waste activated sludge using membrane technology. This process typically features an anoxic tank, an aerated membrane thickener operating in loop with a first-stage digester followed by second-stage digestion. Membrane thickening aerobic digestion processes can handle sludge from any liquid treatment process and is best for facilities obligated to meet low total phosphorus and nitrogen discharge limits. Membrane thickening aerobic digestion processes offer many advantages including: producing a reusable quality permeate with minimal levels of total phosphorus and nitrogen that can be recycled to the head works of a plant, protecting the performance of a biological nutrient removal liquid treatment process without requiring chemical addition, providing reliable thickening up to 4% solids concentration without the use of polymers or attention to decanting, increasing sludge storage capacities in existing tanks, minimizing the footprint of new tanks, reducing disposal costs, and providing Class B stabilization.

Valuation of OSA process and folic acid addition as excess sludge minimization alternatives applied in the activated sludge process.

PubMed

Martins, C L; Velho, V F; Ramos, S R A; Pires, A S C D; Duarte, E C N F A; Costa, R H R

2016-01-01

The aim of this study was to investigate the ability of the oxic-settling-anaerobic (OSA)-process and the folic acid addition applied in the activated sludge process to reduce the excess sludge production. The study was monitored during two distinct periods: activated sludge system with OSA-process, and activated sludge system with folic acid addition. The observed sludge yields (Yobs) were 0.30 and 0.08 kgTSS kg(-1) chemical oxygen demand (COD), control phase and OSA-process (period 1); 0.33 and 0.18 kgTSS kg(-1) COD, control phase and folic acid addition (period 2). The Yobs decreased by 73 and 45% in phases with the OSA-process and folic acid addition, respectively, compared with the control phases. The sludge minimization alternatives result in a decrease in excess sludge production, without negatively affecting the performance of the effluent treatment.

An examination of the treatment of iron-dosed waste activated sludge by anaerobic digestion.

PubMed

Johnson, D K; Carliell-Marquet, C M; Forster, C F

2003-08-01

Anaerobic digestion is an important sludge treatment process enabling stabilisation of the organic fraction of sewage sludge prior to land application. Any practice which might retard the anaerobic digestion process will jeopardize the stability of the resulting digested sludge. This paper reports on an investigation into the relative digestibility of iron-dosed waste activated sludge (WAS) from a sewage treatment works (STW) with chemical phosphorus removal (CPR), in comparison to WAS from a works without phosphorus removal. Two laboratory scale anaerobic digesters (51) were fed initially with non iron-dosed WAS (Works M) at a solids retention time of 19 days. After 2 months the iron-dosed CPR sludge (Works R) was introduced into the second digester, resulting in a 32% decrease in biogas production and an increase in the methane content of the biogas from an average of 74% to 81%. Pre-treatment of the CPR sludge with sodium sulphide and shear, both alone and in combination, caused the gas production to deteriorate further. Pre-acidification and pre-treatment with EDTA did result in an enhanced gas production but it was still not comparable with that of the digester being fed with non-iron-dosed sludge. The daily gas production was found to be linearly related to the amount of bound iron in the sludge.

Utilization of Drinking Water Treatment Slurry to Produce Aluminum Sulfate Coagulant.

PubMed

Fouad, Mahmoud M; Razek, Taha M A; Elgendy, Ahmed S

2017-02-01

  In Egypt, water treatment consumes about 365 000 tons of aluminum sulfate and produces more than 100 million tons of sludge per year. The common disposal system of sludge in Egypt is to discharge it into natural waterways. Toxicity of aluminum, environmental regulations and costs of chemicals used in water treatment and sludge treatment processes led to an evaluation of coagulant recovery and subsequent reuse. The present work aimed at aluminum recovery from sludge of El-Shiekh Zayd water treatment plant (WTP) to produce aluminum sulfate coagulant. Sludge was characterized and the effect of five variables was tested and the process efficiency was evaluated at different operating conditions. Maximum recovery is 94.2% at acid concentration 1.5 N, sludge weight 5 g, mixing speed 60 rpm, temperature 60 °C and leaching time 40 min. Then optimum conditions were applied to get maximum recovery for aluminum sulfate and compared to commercial coagulant on raw water of El-Shiekh Zayd (WTP).

Transformation of heavy metal speciation during sludge drying: mechanistic insights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weng, Huanxin; Ma, Xue-Wen; Fu, Feng-Xia

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized the Cr, Cu, Cd and Pb in sludge by transforming acid-soluble, reducible andmore » oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.« less

Characterization and biodegradability of sludge from a high rate A-stage contact tank and B-stage membrane bioreactor of a pilot-scale AB system treating municipal wastewaters.

PubMed

Trzcinski, Antoine Prandota; Ganda, Lily; Kunacheva, Chinagarn; Zhang, Dong Qing; Lin, Li Leonard; Tao, Guihe; Lee, Yingjie; Ng, Wun Jern

2016-10-01

In light of global warming mitigation efforts, increasing sludge disposal costs, and need for reduction in the carbon footprint of wastewater treatment plants, innovation in treatment technology has been tailored towards energy self-sufficiency. The AB process is a promising technology for achieving maximal energy recovery from wastewaters with minimum energy expenditure and therefore inherently reducing excess sludge production. Characterization of this novel sludge and its comparison with the more conventional B-stage sludge are necessary for a deeper understanding of AB treatment process design. This paper presents a case study of a pilot-scale AB system treating municipal wastewaters as well as a bio- (biochemical methane potential and adenosine tri-phosphate analysis) and physico-chemical properties (chemical oxygen demand, sludge volume index, dewaterability, calorific value, zeta potential and particle size distribution) comparison of the organic-rich A-stage against the B-stage activated sludge. Compared to the B-sludge, the A-sludge yielded 1.4 to 4.9 times more methane throughout the 62-week operation.

Reduction of sludge production from WWTP using thermal pretreatment and enhanced anaerobic methanisation.

PubMed

Graja, S; Chauzy, J; Fernandes, P; Patria, L; Cretenot, D

2005-01-01

The objective of the study presented here was to investigate the performance of an enhanced two-step anaerobic process for the treatment of WWTP sludge. This process was developed to answer the urgent need currently faced by WWTP operators to reduce the production of biosolids, for which disposal pathways are facing increasing difficulties. A pilot plant was operated on a full-scale WWTP (2,500 p.e.) over a period of 4 months. It consisted of a thermal pre-treatment of excess sludge at 175 degrees C and 40 min, followed by dewatering and methanisation of the centrate in a fixed-film reactor. The thermal lysis had a two-fold enhancing effect on sludge reduction efficiency: firstly, it allowed a decrease of the HRT in the methaniser to 2.9 days and secondly, it yielded biosolids with a high dewaterability. This contributed to further reductions in the final volume of sludge to be disposed of. The two-step process achieved a sludge reduction efficiency of 65% as TSS, thus giving an interesting treatment option for WWTP facing sludge disposal problems.

Advanced oxidation process using hydrogen peroxide/microwave system for solubilization of phosphate.

PubMed

Liao, Ping Huang; Wong, Wayne T; Lo, Kwang Victor

2005-01-01

An advanced oxidation process (AOP) combining hydrogen peroxide and microwave heating was used for the solubilization of phosphate from secondary municipal sludge from an enhanced biological phosphorus removal process. The microwave irradiation is used as a generator agent of oxidizing radicals as well as a heating source in the process. This AOP process could facilitate the release of a large amount of the sludge-bound phosphorus from the sewage sludge. More than 84% of the total phosphorous could be released at a microwave heating time of 5 min at 170 degrees C. This innovative process has the potential of being applied to simple sludge treatment processes in domestic wastewater treatment and to the recovery of phosphorus from the wastewater.

Feedstock and process influence on biodiesel produced from waste sewage sludge.

PubMed

Capodaglio, Andrea G; Callegari, Arianna

2018-06-15

Disposal of sewage sludge is one of the most important issues in wastewater treatment throughout Europe, as EU sludge production, estimated at 9.5 million tons dry weight in 2005, is expected to approach 13 million tons in 2020. While sludge disposal costs may constitute 30-50% of the total operation costs of wastewater treatment processes, waste sewage sludge still contains resources that may be put to use, like nutrients and energy, that can be recovered through a variety of approaches. Research has shown that waste sewage sludge can be a valuable and very productive feedstock for biodiesel generation, containing lipids (the fats from which biofuels are extracted) in amounts that would require large areas cultivated with typical biodiesel feedstock, to produce, and at a much lower final cost. Several methods have been tested for the production of biodiesel from sewage sludge. To date, among the most efficient such process is pyrolysis, and in particular Microwave-Assisted Pyrolysis (MAP), under which process conditions are more favorable in energetic and economic terms. Sludge characteristics are very variable, depending on the characteristics of the wastewater-generating service area and on the wastewater treatment process itself. Each sludge can be considered a unique case, and as such experimental determination of the optimal biodiesel yields must be conducted on a case-by-case basis. In addition to biodiesel, other pyrolysis products can add to the energetic yield of the process (and not only). This paper discusses how feedstock properties and process characteristics may influence biodiesel (and other products) yield from pyrolytic (and in particular, MAP) processes, and discusses future possible technological developments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of NASA-developed technology to the automatic control of municipal sewage treatment plants

NASA Technical Reports Server (NTRS)

Hiser, L. L.; Herrera, W. R.

1973-01-01

A search was made of NASA developed technology and commercial technology for process control sensors and instrumentation which would be applicable to the operation of municipal sewage treatment plants. Several notable items were found from which process control concepts were formulated that incorporated these items into systems to automatically operate municipal sewage treatment plants. A preliminary design of the most promising concept was developed into a process control scheme for an activated sludge treatment plant. This design included process control mechanisms for maintaining constant food to sludge mass (F/M) ratio, and for such unit processes as primary sedimentation, sludge wastage, and underflow control from the final clarifier.

Hydrothermal Testing of K Basin Sludge and N Reactor Fuel at Sludge Treatment Project Operating Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delegard, Calvin H.; Schmidt, Andrew J.; Thornton, Brenda M.

The Sludge Treatment Project (STP), managed for the U. S. DOE by Fluor Hanford (FH), was created to design and operate a process to eliminate uranium metal from K Basin sludge prior to packaging for Waste Isolation Pilot Plant (WIPP). The STP process uses high temperature liquid water to accelerate the reaction, produce uranium dioxide from the uranium metal, and safely discharge the hydrogen. Under nominal process conditions, the sludge will be heated in pressurized water at 185°C for as long as 72 hours to assure the complete reaction (corrosion) of up to 0.25-inch diameter uranium metal pieces. Under contractmore » to FH, the Pacific Northwest National Laboratory (PNNL) conducted bench-scale testing of the STP hydrothermal process in November and December 2006. Five tests (~50 ml each) were conducted in sealed, un-agitated reaction vessels under the hydrothermal conditions (e.g., 7 to 72 h at 185°C) of the STP corrosion process using radioactive sludge samples collected from the K East Basin and particles/coupons of N Reactor fuel also taken from the K Basins. The tests were designed to evaluate and understand the chemical changes that may be occurring and the effects that any changes would have on sludge rheological properties. The tests were not designed to evaluate engineering aspects of the process. The hydrothermal treatment affected the chemical and physical properties of the sludge. In each test, significant uranium compound phase changes were identified, resulting from dehydration and chemical reduction reactions. Physical properties of the sludge were significantly altered from their initial, as-settled sludge values, including, shear strength, settled density, weight percent water, and gas retention.« less

Alkaline treatment of high-solids sludge and its application to anaerobic digestion.

PubMed

Li, Chenchen; Li, Huan; Zhang, Yuyao

2015-01-01

High-solids anaerobic digestion is a promising new process for sludge reduction and bioenergy recovery, requiring smaller digestion tanks and less energy for heating, but a longer digestion time, than traditional low-solids anaerobic digestion. To accelerate this process, alkaline sludge disintegration was tested as a pretreatment method for anaerobic digestion of high-solids sludge. The results showed that alkaline treatment effectively disintegrated both low-solids sludge and high-solids sludge, and treatment duration of 30 min was the most efficient. The relation between sludge disintegration degree and NaOH dose can be described by a transmutative power function model. At NaOH dose lower than 0.2 mol/L, sludge disintegration degree remained virtually unchanged when sludge total solids (TS) content increased from 2.0 to 11.0%, and decreased only slightly when sludge TS increased to 14.2%. Although high-solids sludge required a slightly higher molarity of NaOH to reach the same disintegration level of low-solids sludge, the required mass of NaOH actually decreased due to sludge thickening. From the view of NaOH consumption, sludge TS of 8-12% and a NaOH dose of 0.05 mol/L were optimum conditions for alkaline pretreatment, which resulted in a slight increase in accumulative biogas yield, but a decrease by 24-29% in digestion time during the subsequent anaerobic digestion.

Stabilization of waste-activated sludge through the anoxic-aerobic digestion process.

PubMed

Hashimoto, S; Fujita, M; Terai, K

1982-08-01

During the aerobic digestion process, the nitrogen which had been embedded in the activated sludge is solubilized to form ammoniacal and nitric nitrogen which are in turn transferred to the liquor and cause the increase of nitrogen loading in the sewage treatment plant. In this study, the anoxic-aerobic sludge digestion system which is a modified form of the conventional aerobic sludge digestion is made up of aerobic and anoxic tanks and are designed to remove both the volatile suspended solids and the total nitrogen (TN) simultaneously. The removal efficiencies of both VSS and TN were investigated by feeding waste-activated sludge continuously and semicontinuously. The maximum percent reduction of both VSS and TN was achieved at a Q(r)/Q(s) ratio of 2 in the continuous process. The semicontinuous process was used to improve the nitrogen removal efficiency further. In the semicontinuous process, the VSS reduction efficiency as well as the nitrogen removal efficiency increased remarkably under a constant Q(r)/Q(s) ratio of 2. This process also achieved a VSS reduction efficiency higher than the aerobic digestion process (control). It was suggested that the additional anoxic tank enhanced the sludge digestion. Furthermore, the anoxic-aerobic digestion system can be applied to other treatment media like the primary sludge, industrial sludge, animal manure, etc.

Comparing the effects of three pre-treatment disintegration techniques on aerobic sludge digestion: biodegradability enhancement and microbial community monitoring by PCR-DGGE.

PubMed

Jaziri, Kais; Casellas, Magali; Dagot, Christophe

2012-06-01

The objectives of this work were to compare and investigate the effect of three activated sludge disintegration processes before aerobic sludge digestion on 1) aerobic biodegradability enhancement and 2) microbial community evolution using the polymerase chain reaction-denaturant gel gradient electrophoresis (PCR-DGGE) technique. The comparison of three disintegration processes: thermal treatment (95 degrees C, 2h), sonication (100,000 kJ/kgTS) and ozonation (0.108 g O3/gTS) showed that the disintegration processes acted differently according to the composition of the soluble phase and to the DNA damage. Thermal treatment led to significant protein solubilization and to DNA modification. Sonication and ozonation resulted in similar soluble phase compositions and did not lead to any DNA modifications. During activated sludge aerobic digestion, intrinsic biodegradability enhancement was observed for thermal and ozone activated sludge pre-treatments. The analysis of the DGGE patterns at the end of aerobic digestion showed that population diversity was affected by both the aerobic digestion and the pre-treatment. The dissimilarity percentages measured at the end of aerobic digestion in the control sample and in the treated sludge were equal to 22, 25 and 20% for thermal treatment, sonication and ozonation respectively. This study indicated that PCR-DGGE could be a useful tool for the comparison of disintegration processes before and after aerobic digestion.

Full-scale phosphorus recovery from digested waste water sludge in Belgium - part I: technical achievements and challenges.

PubMed

Marchi, A; Geerts, S; Weemaes, M; Schiettecatte, W; Wim, S; Vanhoof, C; Christine, V

2015-01-01

To date, phosphorus recovery as struvite in wastewater treatment plants has been mainly implemented on water phases resulting from dewatering processes of the sludge line. However, it is possible to recover struvite directly from sludge phases. Besides minimising the return loads of phosphorus from the sludge line to the water line, placing such a process within the sludge line is claimed to offer advantages such as a higher recovery potential, enhanced dewaterability of the treated sludge, and reduced speed of scaling in pipes and dewatering devices. In the wastewater treatment plant at Leuven (Belgium), a full-scale struvite recovery process from digested sludge has been tested for 1 year. Several monitoring campaigns and experiments provided indications of the efficiency of the process for recovery. The load of phosphorus from the sludge line returning to the water line as centrate accounted for 15% of the P-load of the plant in the reference situation. Data indicated that the process divides this phosphorus load by two. An improved dewaterability of 1.5% of dry solids content was achieved, provided a proper tuning of the installation. Quality analyses showed that the formed struvite was quite pure.

A multi-disciplinary approach to the removal of emerging contaminants in municipal wastewater treatment plans in New York State, 2003-2004

USGS Publications Warehouse

Philips, Patrick J.; Stinson, Beverley; Zaugg, Steven D.; Furlong, Edward T.; Kolpin, Dana W.; Esposito, Kathleen; Bodniewicz, B.; Pape, R.; Anderson, J.

2005-01-01

The second phase of the study focused on one of the most common wastewater treatment processes operated in the United States, the Activated Sludge process. Using four controlled parallel activated sludge pilots, a more detailed assessment of the impact of Sludge Retention Time (SRT) on the reduction or removal of ECs was performed.

Composition and aggregation of extracellular polymeric substances (EPS) in hyperhaline and municipal wastewater treatment plants

PubMed Central

Zeng, Jie; Gao, Jun-Min; Chen, You-Peng; Yan, Peng; Dong, Yang; Shen, Yu; Guo, Jin-Song; Zeng, Ni; Zhang, Peng

2016-01-01

As important constituents of activated sludge flocs, extracellular polymeric substances (EPS) play significant roles in pollutants adsorption, the formation and maintenance of microbial aggregates, and the protection of microbes from external environmental stresses. In this work, EPS in activated sludge from a municipal wastewater treatment plant (M-WWTP) with anaerobic/anoxic/oxic (A2/O) process and a hyperhaline wastewater treatment plant (H-WWTP) with anaerobic/oxic (A/O) process were extracted by ultrasound method. The proteins and polysaccharides contents in EPS were determined by using a modified Lowry method and anthrone colorimetry respectively to analyze the detail differences in two types of WWTPs. Fourier transform-infrared spectroscopy and three-dimensional excitation-emission matrix fluorescence spectroscopy demonstrated proteins and polysaccharides were the dominant components of the two types of EPS, and the aromatic protein-like substances accounted for a larger proportion in EPS proteins. The results of the aggregation test indicated that EPS were good for the sludge aggregation, and the EPS in oxic sludge were more beneficial to sludge aggregation than that in anoxic sludge. Anoxic sludge EPS in H-WWTP showed a negligible effect on sludge aggregation. Comparative study on EPS of different tanks in the M-WWTP and H-WWTP was valuable for understanding the characteristics of EPS isolated from two typical wastewater treatment processes. PMID:27220287

Research on Treatment Technology and Device of Oily Sludge

NASA Astrophysics Data System (ADS)

Wang, J. Q.; Shui, F. S.; Li, Q. F.

2017-12-01

Oily sludge is a solid oily waste, which is produced during the process of oil exploitation, transportation, refining and treatment of oily sewage. It contains a great number of hazardous substance, and is difficult to handle with. To solve the problem of waste resources of oil sludge with high oil content and usually not easy to aggregate during the preparation of profile control agent, a new oily sludge treatment device was developed. This device consists of heat supply unit, flush and filter unit, oil removal unit and dehydration unit. It can effectively clean and filter out the waste from oily sludge, recycle the oil resources and reduce the water content of the residue. In the process of operation, the water and chemical agent are recycled in the device, eventually producing little sewage. The device is small, easy to move and has high degree of automation control. The experimental application shows that the oil removal rate of the oily sludge is up to 70%, and the higher the oil content rate the better the treatment.

Effects of irradiation intensity and pH on nutrients release and solids destruction of waste activated sludge using the microwave-enhanced advanced oxidation process.

PubMed

Chan, W I; Liao, P H; Lo, K V

2010-11-01

Using the microwave-enhanced advanced oxidation process (MW/H2O2-AOP), the pH and irradiation intensity on waste activated sludge samples were investigated to provide insight to the athermal effects on nutrients release, solids destruction, particle size distribution and dewaterability, and to demonstrate their interrelationships. Carbonaceous matters and nutrients released into solution depended on the irradiation intensity and time. Higher irradiation levels tended to be more effective in the solubilization of nutrients and had more pronounced effects in the dewaterability of sludge. In terms of particle size distribution, detectable particles increased in size for treatments in acidic conditions, while the dewaterability of treated sludge was improved. In treatments under neutral and alkaline conditions, the particle size range increased, with more small particles formed, thereby significantly deteriorating the dewaterability of sludge treated in alkaline conditions. The best results for the solubilization of nutrients were in alkaline conditions with high irradiation power, but dewaterability of the sludge was compromised. Sludge treatment with the MW/H2O2-AOP in acidic conditions with high irradiation power yielded the best dewaterable sludge and significant nutrient solubilization; therefore, it is the recommended treatment condition for activated sludge.

Fate of stable strontium in the sewage treatment process as an analog for radiostrontium released by nuclear accidents.

PubMed

Kamei-Ishikawa, Nao; Ito, Ayumi; Umita, Teruyuki

2013-09-15

Radionuclides were widely released into the environment due to the nuclear accident at the Fukushima Daiichi Nuclear Power Plant. Some of these radionuclides have flowed into municipal sewage treatment plants through sewer systems. We have observed the fate of stable Sr in the sewage treatment process as a means to predict the fate of radiostrontium. Concentrations of stable Sr were determined in sewage influent, effluent, dewatered sludge, and incinerated sewage sludge ash collected from a sewage treatment plant once a month from July to December 2011. In the mass balance of Sr in the sewage treatment plant, 76% of the Sr entering the plant was discharged to the receiving water on average. Additionally, 14% of the Sr flowing through the plant was transferred to the sewage sludge and then concentrated in the sludge ash without being released to the atmosphere. We also investigated Sr sorption by activated sludge in a batch experiment. Measurements at 3 and 6h after the contact showed Sr was sorbed in the activated sludge; however, the measurements indicated Sr desorption from activated sludge occurred 48 h after the contact. Copyright © 2013 Elsevier B.V. All rights reserved.

Microplastics in Sewage Sludge: Effects of Treatment.

PubMed

Mahon, A M; O'Connell, B; Healy, M G; O'Connor, I; Officer, R; Nash, R; Morrison, L

2017-01-17

Waste water treatment plants (WWTPs) are receptors for the cumulative loading of microplastics (MPs) derived from industry, landfill, domestic wastewater and stormwater. The partitioning of MPs through the settlement processes of wastewater treatment results in the majority becoming entrained in the sewage sludge. This study characterized MPs in sludge samples from seven WWTPs in Ireland which use anaerobic digestion (AD), thermal drying (TD), or lime stabilization (LS) treatment processes. Abundances ranged from 4196 to 15 385 particles kg -1 (dry weight). Results of a general linear mixed model (GLMM) showed significantly higher abundances of MPs in smaller size classes in the LS samples, suggesting that the treatment process of LS shears MP particles. In contrast, lower abundances of MPs found in the AD samples suggests that this process may reduce MP abundances. Surface morphologies examined using scanning electron microscopy (SEM) showed characteristics of melting and blistering of TD MPs and shredding and flaking of LS MPs. This study highlights the potential for sewage sludge treatment processes to affect the risk of MP pollution prior to land spreading and may have implications for legislation governing the application of biosolids to agricultural land.

Gas composition of sludge residue profiles in a sludge treatment reed bed between loadings.

PubMed

Larsen, Julie D; Nielsen, Steen M; Scheutz, Charlotte

2017-11-01

Treatment of sludge in sludge treatment reed bed systems includes dewatering and mineralization. The mineralization process, which is driven by microorganisms, produces different gas species as by-products. The pore space composition of the gas species provides useful information on the biological processes occurring in the sludge residue. In this study, we measured the change in composition of gas species in the pore space at different depth levels in vertical sludge residue profiles during a resting period of 32 days. The gas composition of the pore space in the sludge residue changed during the resting period. As the resting period proceeded, atmospheric air re-entered the pore space at all depth levels. The methane (CH 4 ) concentration was at its highest during the first part of the resting period, and then declined as the sludge residue became more dewatered and thereby aerated. In the pore space, the concentration of CH 4 often exceeded the concentration of carbon dioxide (CO 2 ). However, the total emission of CO 2 from the surface of the sludge residue exceeded the total emission of CH 4 , suggesting that CO 2 was mainly produced in the layer of newly applied sludge and/or that CO 2 was emitted from the sludge residue more readily compared to CH 4 .

Relationship between enhanced dewaterability and structural properties of hydrothermal sludge after hydrothermal treatment of excess sludge.

PubMed

Wang, Liping; Li, Aimin; Chang, Yuzhi

2017-04-01

Hydrothermal treatment is an effective method to enhance the deep dewaterability of excess sludge with low energy consumption. In this study, an insight into the relationship between enhanced dewaterability and structural properties of the produced hydrothermal sludge was presented, aiming at better understanding the effect of hydrothermal process on excess sludge dewatering performance. The results indicated that hydrothermal effect induced the transformation of surface water to interstitial and free water by lowering the binding strength between adjacent water and solid particles and that free water became the main form for moisture existence in hydrothermal sludge as temperature was higher than 180 °C. Increase in temperature of hydrothermal treatment generated a significant size reduction of sludge flocs but treated sludge with a higher rigidity, which not only strengthened the network of hydrothermal sludge but also destroyed the binding of EPS with water. Hydrothermal process caused crevice and pore structures of excess sludge to disappear gradually, which was a main driving force of water removal as temperature was below 150 °C. With the temperature of hydrothermal treatment exceeding 180 °C, the morphology of hydrothermal sludge became rough which linked closely to the solid precipitation of condensation polymerization, and further became smooth at higher temperature (210 °C) due to the coal-like structures with higher aromaticities, indicating that hydrothermal reaction pathways began to play a main role in enhanced dewaterability. Hydrothermal treatment led to more alkyl and aromatic carbon, but lower O-alkyl, carboxyl and carbonyl carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improvement of anaerobic digestion of sewage sludge through microwave pre-treatment.

PubMed

Serrano, A; Siles, J A; Martín, M A; Chica, A F; Estévez-Pastor, F S; Toro-Baptista, E

2016-07-15

Sewage sludge generated in the activated sludge process is a polluting waste that must be treated adequately to avoid important environmental impacts. Traditional management methods, such as landfill disposal or incineration, are being ruled out due to the high content in heavy metal, pathogens, micropolluting compounds of the sewage sludge and the lack of use of resources. Anaerobic digestion could be an interesting treatment, but must be improved since the biomethanisation of sewage sludge entails low biodegradability and low methane production. A microwave pre-treatment at pilot scale is proposed to increase the organic matter solubilisation of sewage sludge and enhance the biomethanisation yield. The operational variables of microwave pre-treatment (power and specific energy applied) were optimised by analysing the physicochemical characteristics of sewage sludge (both total and soluble fraction) under different pre-treatment conditions. According to the variation in the sCOD and TN concentration, the optimal operation variables of the pre-treatment were fixed at 20,000 J/g TS and 700 W. A subsequent anaerobic digestion test was carried out with raw and pre-treated sewage sludge under different conditions (20,000 J/g TS and 700 W; 20,000 J/g TS and 400 W; and 30,000 J/g TS and 400 W). Although stability was maintained throughout the process, the enhancement in the total methane yield was not high (up to 17%). Nevertheless, very promising improvements were determined for the kinetics of the process, where the rG and the OLR increased by 43% and 39%, respectively, after carrying out a pre-treatment at 20,000 J/g TS and 700 W. Copyright © 2016 Elsevier Ltd. All rights reserved.

Overview of current biological and thermo-chemical treatment technologies for sustainable sludge management.

PubMed

Zhang, Linghong; Xu, Chunbao Charles; Champagne, Pascale; Mabee, Warren

2014-07-01

Sludge is a semi-solid residue produced from wastewater treatment processes. It contains biodegradable and recalcitrant organic compounds, as well as pathogens, heavy metals, and other inorganic constituents. Sludge can also be considered a source of nutrients and energy, which could be recovered using economically viable approaches. In the present paper, several commonly used sludge treatment processes including land application, composting, landfilling, anaerobic digestion, and combustion are reviewed, along with their potentials for energy and product recovery. In addition, some innovative thermo-chemical techniques in pyrolysis, gasification, liquefaction, and wet oxidation are briefly introduced. Finally, a brief summary of selected published works on the life cycle assessment of a variety of sludge treatment and end-use scenarios is presented in order to better understand the overall energy balance and environmental burdens associated with each sludge treatment pathway. In all scenarios investigated, the reuse of bioenergy and by-products has been shown to be of crucial importance in enhancing the overall energy efficiency and reducing the carbon footprint. © The Author(s) 2014.

Transformation of heavy metal speciation during sludge drying: mechanistic insights.

PubMed

Weng, Huan-Xin; Ma, Xue-Wen; Fu, Feng-Xia; Zhang, Jin-Jun; Liu, Zan; Tian, Li-Xun; Liu, Chongxuan

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized Cr, Cu, Cd, and Pb in sludge by transforming acid-soluble, reducible, and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge. Copyright © 2013 Elsevier B.V. All rights reserved.

Activated Sludge. Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Boe, Owen K.; Klopping, Paul H.

This student manual contains the textual material for a seven-lesson unit on activated sludge. Topic areas addressed in the lessons include: (1) activated sludge concepts and components (including aeration tanks, aeration systems, clarifiers, and sludge pumping systems); (2) activated sludge variations and modes; (3) biological nature of activated…

Enhancement of activated sludge disintegration and dewaterability by Fenton process

NASA Astrophysics Data System (ADS)

Heng, G. C.; Isa, M. H.

2016-06-01

Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.

[Characteristics of novel wastewater treatment technology by swimming bed combined with aerobic granular sludge].

PubMed

Zhang, Yan; Wang, Yong-sheng; Bai, Yu-hua; Chen, Chen; Lü, Jian; Zhang, Jie

2007-10-01

Swimming bed combined with aerobic granular sludge as a novel technology for wastewater treatment was developed, which was on the basis of the biofilm process and activated sludge process, and results demonstrated notable performance of high-efficiency treatment capability and sludge reduction. Even when hydraulic retention time (HRT) was only at 3.2 h with average COD volumetric loading of 2.03 kg/(m3 x d) and NH4(+)-N of 0.52 kg/(m3 X d), 90.9% of average COD removal rate and 98.3% of NH4(+)-N removal rate were achieved. Aerobic granular sludge appeared with spherical or rod shape after 16 days operation. Mixed liquor suspended solid (MLSS) concentrations in the reactor reached 5,640 mg/L at the highest during operation period, and the average ratio of mixed liquor volatile suspended solid (MLVSS) to MLSS reached 0.87. Furthermore, microscopic observation of biofilm and aerobic granules revealed much presence of protozoa and metazoa on the biofilm and suspended sludge, and this long food chain can contribute to the sludge reduction. Only 0. 175 5 of sludge yields (MLSS/ CODremoved) was obtained in the experiment, which was only about 50% of the conventional aerobic processes.

Analysis on carbon dioxide emission reduction during the anaerobic synergetic digestion technology of sludge and kitchen waste: Taking kitchen waste synergetic digestion project in Zhenjiang as an example.

PubMed

Guo, Qia; Dai, Xiaohu

2017-11-01

With the popularization of municipal sewage treatment facilities, the improvement of sewage treatment efficiency and the deepening degree of sewage treatment, the sludge production of sewage plant has been sharply increased. Carbon emission during the process of municipal sewage treatment and disposal has become one of the important sources of greenhouse gases that cause greenhouse effect. How to reduce carbon dioxide emissions during sewage treatment and disposal process is of great significance for reducing air pollution. Kitchen waste and excess sludge, as two important organic wastes, once uses anaerobic synergetic digestion technology in the treatment process can on the one hand, avoid instability of sludge individual anaerobic digestion, improve sludge degradation rate and marsh gas production rate, and on the other hand, help increase the reduction of carbon dioxide emissions to a great extent. The paper uses material balance method, analyzes and calculates the carbon dioxide emissions from kitchen waste and sludge disposed by the anaerobic synergetic digestion technology, compares the anaerobic synergetic digestion technology with traditional sludge sanitary landfill technology and works out the carbon dioxide emission reductions after synergetic digestion. It takes the kitchen waste and sludge synergetic digestion engineering project of Zhenjiang city in Jiangsu province as an example, makes material balance analysis using concrete data and works out the carbon dioxide daily emission reductions. The paper analyzes the actual situation of emission reduction by comparing the data, and found that the synergetic digestion of kitchen waste and sludge can effectively reduce the carbon dioxide emission, and the reduction is obvious especially compared with that of sludge sanitary landfill, which has a certain effect on whether to promote the use of the technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of laboratory-scale thermophilic biofilm and activated sludge processes integrated with a mesophilic activated sludge process.

PubMed

Suvilampi, J; Lehtomäki, A; Rintala, J

2003-07-01

A combined thermophilic-mesophilic wastewater treatment was studied using a laboratory-scale thermophilic activated sludge process (ASP) followed by mesophilic ASP or a thermophilic suspended carrier biofilm process (SCBP) followed by mesophilic ASP, both systems treating diluted molasses (dilution factor 1:500 corresponding GF/A-filtered COD (COD(filt)) of 1900+/-190 mgl(-1)). With hydraulic retention times (HRTs) of 12-18 h the thermophilic ASP and thermophilic SCBP removed 60+/-13% and 62+/-7% of COD(filt), respectively, with HRT of 8 h the removals were 48+/-1% and 69+/-4%. The sludge volume index (SVI) was notably lower in the thermophilic SCBP (measured from suspended sludge) than in the thermophilic ASP. Under the lowest HRT the mesophilic ASP gave better performance (as SVI, COD(filt), and COD(tot) removals) after the thermophilic SCBP than after the thermophilic ASP. Measured sludge yields were low (less than 0.1 kg suspended solids (SS) kg COD(filt removed)(-1)) in all processes. Both thermophilic treatments removed 80-85% of soluble COD (COD(sol)) whereas suspended COD (COD(susp)) and colloidal COD (COD(col)) were increased. Both mesophilic post-treatments removed all COD(col) and most of the COD(susp) from the thermophilic effluents. In conclusion, combined thermophilic-mesophilic treatment appeared to be easily operable and produced high effluent quality.

Thermo-Oxidization of Municipal Wastewater Treatment Plant Sludge for Production of Class A Biosolids

EPA Science Inventory

Bench-scale reactors were used to test a novel thermo-oxidation process on municipal wastewater treatment plant (WWTP) waste activated sludge (WAS) using hydrogen peroxide (H₂O₂) to achieve a Class A sludge product appropriate for land application. Reactor ...

Coagulation efficiency and flocs characteristics of recycling sludge during treatment of low temperature and micro-polluted water.

PubMed

Zhou, Zhiwei; Yang, Yanling; Li, Xing; Gao, Wei; Liang, Heng; Li, Guibai

2012-01-01

Drinking water treatment sludge, characterized as accumulated suspended solids and organic and inorganic matter, is produced in large quantities during the coagulation process. The proper disposal, regeneration or reuse of sludge is, therefore, a significant environmental issue. Reused sludge at low temperatures is an alternative method to enhance traditional coagulation efficiency. In the present study, the recycling mass of mixed sludge and properties of raw water (such as pH and turbidity) were systematically investigated to optimize coagulation efficiency. We determined that the appropriate dosage of mixed sludge was 60 mL/L, effective initial turbidity ranges were below 45.0 NTU, and optimal pH for DOMs and turbidity removal was 6.5-7.0 and 8.0, respectively. Furthermore, by comparing the flocs characteristics with and without recycling sludge, we found that floc structures with sludge were more irregular with average size growth to 64.7 microm from 48.1 microm. Recycling sludge was a feasible and successful method for enhancing pollutants removal, and the more irregular flocs structure after recycling might be caused by breakage of reused flocs and incorporation of powdered activated carbon into larger flocs structure. Applied during the coagulation process, recycling sludge could be significant for the treatment of low temperature and micro-polluted source water.

Optimization of a thermal hydrolysis process for sludge pre-treatment.

PubMed

Sapkaite, I; Barrado, E; Fdz-Polanco, F; Pérez-Elvira, S I

2017-05-01

At industrial scale, thermal hydrolysis is the most used process to enhance biodegradability of the sludge produced in wastewater treatment plants. Through statistically guided Box-Behnken experimental design, the present study analyses the effect of TH as pre-treatment applied to activated sludge. The selected process variables were temperature (130-180 °C), time (5-50 min) and decompression mode (slow or steam-explosion effect), and the parameters evaluated were sludge solubilisation and methane production by anaerobic digestion. A quadratic polynomial model was generated to compare the process performance for the 15 different combinations of operation conditions by modifying the process variables evaluated. The statistical analysis performed exhibited that methane production and solubility were significantly affected by pre-treatment time and temperature. During high intensity pre-treatment (high temperature and long times), the solubility increased sharply while the methane production exhibited the opposite behaviour, indicating the formation of some soluble but non-biodegradable materials. Therefore, solubilisation is not a reliable parameter to quantify the efficiency of a thermal hydrolysis pre-treatment, since it is not directly related to methane production. Based on the operational parameters optimization, the estimated optimal thermal hydrolysis conditions to enhance of sewage sludge digestion were: 140-170 °C heating temperature, 5-35min residence time, and one sudden decompression. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stabilization of heavy metals in fired clay brick incorporated with wastewater treatment plant sludge: Leaching analysis

NASA Astrophysics Data System (ADS)

Kadir, A. A.; Hassan, M. I. H.; Salim, N. S. A.; Sarani, N. A.; Ahmad, S.; Rahmat, N. A. I.

2018-04-01

Wastewater treatment sludge or known as sewage sludge is regarded as the residue and produced by the sedimentation of the suspended solid during treatment at the wastewater treatment plant. As such, this sludge was gained from the separation process of the liquids and solids. This sludge wastes has becomes national issues in recent years due to the increasing amount caused by population and industrialization growth in Malaysia. This research was conducted to fully utilize the sludge that rich in dangerous heavy metals and at the same time act as low cost alternative materials in brick manufacturing. The investigation includes determination of heavy metal concentration and chemical composition of the sludge, physical and mechanical properties. Wastewater treatment sludge samples were collected from wastewater treatment plant located in Johor, Malaysia. X-Ray Fluorescence was conducted to determine the heavy metals concentration of wastewater treatment sludge. Different percentage of sludges which are 0%, 1%, 5%, 10%, and 20%, has been incorporated into fired clay brick. The leachability of heavy metals in fired clay brick that incorporated with sludge were determined by using Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leachability Procedure (SPLP) that has been analyzed by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results show a possibility to stabilize the heavy metals in fired clay brick incorporated with wastewater treatment sludge. 20% of the sludge incorporated into the brick is the most suitable for building materials as it leached less heavy metals concentration and complying with USEPA standard.

Persistence of pathogenic prion protein during simulated wastewater treatment processes

USGS Publications Warehouse

Hinckley, G.T.; Johnson, C.J.; Jacobson, K.H.; Bartholomay, C.; Mcmahon, K.D.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

2008-01-01

Transmissible spongiform encephalopathies (TSEs, prion diseases) are a class of fatal neurodegenerative diseases affecting a variety of mammalian species including humans. A misfolded form of the prion protein (PrP TSE) is the major, if not sole, component of the infectious agent. Prions are highly resistant to degradation and to many disinfection procedures suggesting that, if prions enter wastewater treatment systems through sewers and/or septic systems (e.g., from slaughterhouses, necropsy laboratories, rural meat processors, private game dressing) or through leachate from landfills that have received TSE-contaminated material, prions could survive conventional wastewater treatment Here, we report the results of experiments examining the partitioning and persistence of PrPTSE during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion. Incubation with activated sludge did not result in significant PrPTSE degradation. PrPTSE and prion infectivity partitioned strongly to activated sludge solids and are expected to enter biosolids treatment processes. A large fraction of PrPTSE survived simulated mesophilic anaerobic sludge digestion. The small reduction in recoverable PrPTSE after 20-d anaerobic sludge digestion appeared attributable to a combination of declining extractability with time and microbial degradation. Our results suggest that if prions were to enter municipal wastewater treatment systems, most would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in treated biosolids. ?? 2008 American Chemical Society.

An energy- and resource-saving technology for utilizing the sludge from thermal power station water treatment facilities

NASA Astrophysics Data System (ADS)

Nikolaeva, L. A.; Khusaenova, A. Z.

2014-05-01

A method for utilizing production wastes is considered, and a process circuit arrangement is proposed for utilizing a mixture of activated silt and sludge from chemical water treatment by incinerating it with possible heat recovery. The sorption capacity of the products from combusting a mixture of activated silt and sludge with respect to gaseous emissions is experimentally determined. A periodic-duty adsorber charged with a fixed bed of sludge is calculated, and the heat-recovery boiler efficiency is estimated together with the technical-economic indicators of the proposed utilization process circuit arrangement.

Toluene in sewage and sludge in wastewater treatment plants.

PubMed

Mrowiec, Bozena

2014-01-01

Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 μg/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and dephosphatation processes, the presence of volatile fatty acids (VFAs) in sewage is required. VFAs are the main product of organic matter hydrolysis from sewage sludge. However, no attention has been given to other products of the process. It has been found that in parallel to VFA production, toluene formation occurred. The formation of toluene in municipal anaerobic sludge digestion processes was investigated. Experiments were performed on a laboratory scale using sludge from primary and secondary settling tanks of municipal treatment plants. The concentration of toluene in the digested sludge from primary settling tanks was found to be about 42,000 μg/L. The digested sludge supernatant liquor returned to the biological dephosphatation and denitrification processes for sewage enrichment can contain up to 16,500 μg/L of toluene.

Performance indicators and indices of sludge management in urban wastewater treatment plants.

PubMed

Silva, C; Saldanha Matos, J; Rosa, M J

2016-12-15

Sludge (or biosolids) management is highly complex and has a significant cost associated with the biosolids disposal, as well as with the energy and flocculant consumption in the sludge processing units. The sludge management performance indicators (PIs) and indices (PXs) are thus core measures of the performance assessment system developed for urban wastewater treatment plants (WWTPs). The key PIs proposed cover the sludge unit production and dry solids concentration (DS), disposal/beneficial use, quality compliance for agricultural use and costs, whereas the complementary PIs assess the plant reliability and the chemical reagents' use. A key PI was also developed for assessing the phosphorus reclamation, namely through the beneficial use of the biosolids and the reclaimed water in agriculture. The results of a field study with 17 Portuguese urban WWTPs in a 5-year period were used to derive the PI reference values which are neither inherent to the PI formulation nor literature-based. Clusters by sludge type (primary, activated, trickling filter and mixed sludge) and by digestion and dewatering processes were analysed and the reference values for sludge production and dry solids were proposed for two clusters: activated sludge or biofilter WWTPs with primary sedimentation, sludge anaerobic digestion and centrifuge dewatering; activated sludge WWTPs without primary sedimentation and anaerobic digestion and with centrifuge dewatering. The key PXs are computed for the DS after each processing unit and the complementary PXs for the energy consumption and the operating conditions DS-determining. The PX reference values are treatment specific and literature based. The PI and PX system was applied to a WWTP and the results demonstrate that it diagnosis the situation and indicates opportunities and measures for improving the WWTP performance in sludge management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nonoxidative removal of organics in the activated sludge process

PubMed Central

Modin, Oskar; Persson, Frank; Wilén, Britt-Marie; Hermansson, Malte

2016-01-01

ABSTRACT The activated sludge process is commonly used to treat wastewater by aerobic oxidation of organic pollutants into carbon dioxide and water. However, several nonoxidative mechanisms can also contribute to removal of organics. Sorption onto activated sludge can remove a large fraction of the colloidal and particulate wastewater organics. Intracellular storage of, e.g., polyhydroxyalkanoates (PHA), triacylglycerides (TAG), or wax esters can convert wastewater organics into precursors for high-value products. Recently, several environmental, economic, and technological drivers have stimulated research on nonoxidative removal of organics for wastewater treatment. In this paper, we review these nonoxidative removal mechanisms as well as the existing and emerging process configurations that make use of them for wastewater treatment. Better utilization of nonoxidative processes in activated sludge could reduce the wasteful aerobic oxidation of organic compounds and lead to more resource-efficient wastewater treatment plants. PMID:27453679

Technological Aspects of Waterworks Sludge Treatment

NASA Astrophysics Data System (ADS)

Belkanova, M. Yu; Nikolaenko, E. V.; Gevel, D. A.

2017-11-01

The water yielding capacity of the sludge in water-supply network treatment facilities is determined by the water quality in a water source and its treatment technology. The paper studies the sludge of water-supply network treatment facilities formed in the conditions of low turbidity and average water colour index in the water source. Such sludge has a low water yielding capacity and is subject to conditioning. The paper shows the influence of seasonal variations of turbidity, water colour index and temperature of the feed water on the specific sludge filtration resistance. It considers the specific features of sludge formation in different settling basins influencing its water yielding capacity. It is shown that the washwater return performed at one of the blocks of the facilities increases the feed water turbidity and leads to the formation of the sludge easily susceptible to conditioning. The paper studies the following methods of the reagent sludge treatment: polyacrylamide-based flocculant treatment, joint treatment with flocculant and vermiculite filler, lime treatment. The use of vermiculite allows to reduce the required flocculant dose. The author determines optimum doses of reagents allowing to direct the sludge for further mechanical dewatering after conditioning. It is shown that, when the sludge is processed with lime, the filtrate formed at dewatering can be reused as an alkalifying agent, which will allow one to cut the costs for the acquisition of reagents.

PROGRESS WITH K BASINS SLUDGE RETRIEVAL STABILIZATION & PACKAGING AT THE HANFORD NUCLEAR SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

KNOLLMEYER, P.M.; PHILLIPS, C; TOWNSON, P.S.

This paper shows how Fluor Hanford and BNG America have combined nuclear plant skills from the U.S. and the U.K. to devise methods to retrieve and treat the sludge that has accumulated in K Basins at the Hanford Site over many years. Retrieving the sludge is the final stage in removing fuel and sludge from the basins to allow them to be decontaminated and decommissioned, so as to remove the threat of contamination of the Columbia River. A description is given of sludge retrieval using vacuum lances and specially developed nozzles and pumps into Consolidation Containers within the basins. Themore » special attention that had to be paid to the heat generation and potential criticality issues with the irradiated uranium-containing sludge is described. The processes developed to re-mobilize the sludge from the Consolidation Containers and pump it through flexible and transportable hose-in-hose piping to the treatment facility are explained with particular note made of dealing with the abrasive nature of the sludge. The treatment facility, housed in an existing Hanford building, is described, and the uranium-corrosion and grout packaging processes explained. The uranium corrosion process is a robust, tempered process very suitable for dealing with a range of differing sludge compositions. Optimization and simplification of the original sludge corrosion process design is described and the use of transportable and reusable equipment is indicated. The processes and techniques described in the paper are shown to have wide applicability to nuclear cleanup.« less

Inhibitory effect of high calcium concentration on municipal solid waste leachate treatment by the activated sludge process.

PubMed

Xia, Yi; He, Pin Jing; Pu, Hong Xia; Lü, Fan; Shao, Li Ming; Zhang, Hua

2017-05-01

This research focused on the inhibitory effects of Ca on the aerobic biological treatment of landfill leachate containing extremely high Ca concentrations. When the Ca concentration in leachate to be treated was more than 4500 mg l -1 , the total organic carbon removal rate was significantly reduced and the processing time to achieve the same removal efficiency was 1.4 times that in the control treatment without added Ca. In contrast, the total nitrogen and ammonia nitrogen (NH 4 + -N) removal efficiencies were positively related to the Ca concentration, increasing from 65.2% to 81.2% and from 69.2% to 83.7%, respectively, when the dosage of added Ca increased from zero to 8000 mg l -1 . During aerobic treatment, the reductions of solution Ca concentration were in the range of 1003-2274 mg l -1 and were matched with increases in the Ca content in the residual sludge. The inhibition threshold of Ca in the leachate treated by the activated sludge process appeared to be 4500 mg l -1 , which could be realized by controlling the influent Ca concentration and using an appropriate sludge return ratio in the activated sludge process.

Organic matter and heavy metals content modeling in sewage sludge treated with reed bed system

NASA Astrophysics Data System (ADS)

Boruszko, Dariusz; Dąbrowski, Wojciech; Malinowski, Paweł

2017-11-01

The long process of sludge stabilization (7-15 years) remarkably reduces the organic matter content and causes the process of sludge humifaction. This paper presents the results of using low-cost methods of sludge treatment in the wastewater treatment plant located in Zambrow, Podlaskie Province. The results of studies on the organic matter and heavy metals content in sewage sludge after treatment in a reed bed system are presented. The aim of the research was to evaluate and model organic matter and heavy metals concentrations during sewage stabilization in reed bed lagoons. The lowest concentration, below 1.3 mg/kg DM of the examined seven heavy metals was mercury (Hg). The highest concentration, exceeding 1300 mg/kg DM was zinc (Zn). The obtained results for the heavy metals in sewage sludge from the reed bed lagoons in Zambrow show that the average content of the analyzed heavy metals is approximately 1620 mg/kg DM. The results of the study demonstrate a high efficiency of low-cost methods used in Zambrów WWTP in terms of the quality of the processed sludge. Sewage sludge from the lowest layer of the reed lagoon (12-14 years of dewatering and transformation) is characterized by the lowest organic matter and heavy metals content. The higher a sediment layer lies, i.e. the shorter the time of processing, the higher is the heavy metals content. This indicates a great role of reeds in the accumulation of these compounds.

[Detection of anaerobic processes and microorganisms in immobilized activated sludge of a wastewater treatment plant with intense aeration].

PubMed

Litti, Iu V; Nekrasova, V K; Kulikov, N I; Siman'kova, M V; Nozhevnikova, A N

2013-01-01

Attached activated sludge from the Krasnaya Polyana (Sochi) wastewater treatment plant was studied after the reconstruction by increased aeration and water recycle, as well as by the installation of a bristle carrier for activated sludge immobilization. The activated sludge biofilms developing under conditions of intense aeration were shown to contain both aerobic and anaerobic microorganisms. Activity of a strictly anaerobic methanogenic community was revealed, which degraded organic compounds to methane, further oxidized by aerobic methanotrophs. Volatile fatty acids, the intermediates of anaerobic degradation of complex organic compounds, were used by both aerobic and anaerobic microorganisms. Anaerobic oxidation of ammonium with nitrite (anammox) and the presence of obligate anammox bacteria were revealed in attached activated sludge biofilms. Simultaneous aerobic and anaerobic degradation of organic contaminants by attached activated sludge provides for high rates of water treatment, stability of the activated sludge under variable environmental conditions, and decreased excess sludge formation.

K-Basins Sludge Treatment and Packaging at the Hanford Site - 13585

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogwell, Thomas W.; Honeyman, James O.; Stegen, Gary

Highly radioactive sludge resulting from the storage of degraded spent nuclear fuel has been consolidated in Engineered Containers (ECs) in the 105-K West Storage Basin located on the Hanford site near the Columbia River in Washington State. CH2M Hill Plateau Remediation Company (CHPRC) is proceeding with a project to retrieve the sludge, place it in Sludge Transport and Storage Containers (STSCs) and store those filled containers within the T Plant Canyon facility on the Hanford Site Central Plateau (Phase 1). Retrieval and transfer of the sludge material will enable removal of the 105-K West Basin and allow remediation of themore » subsurface contamination plumes under the basin. The U.S. Department of Energy (DOE) plans to treat and dispose of this K Basins sludge (Phase 2) as Remote Handled Transuranic Waste (RH TRU) at the Waste Isolation Pilot Plant (WIPP) located in New Mexico. The K Basin sludge currently contains uranium metal which reacts with water present in the stored slurry, generating hydrogen and other byproducts. The established transportation and disposal requirements require the transformation of the K Basins sludge to a chemically stable, liquid-free, packaged waste form. The Treatment and Packaging Project includes removal of the containerised sludge from T Plant, the treatment of the sludge as required, and packaging of all the sludge into a form that is certifiable for transportation to and disposal at WIPP. Completion of this scope will require construction and operation of a Sludge Treatment and Packaging Facility (STPF), which could be either a completely new facility or a modification of an existing Hanford Site facility. A Technology Evaluation and Alternatives Analysis (TEAA) for the STP Phase 2 was completed in 2011. A Request for Technology Information (RFI) had been issued in October 2009 to solicit candidate technologies for use in Phase 2. The RFI also included a preliminary definition of Phase 2 functions and requirements. Potentially applicable technologies were identified through a commercial procurement process, technical workshops, and review of the numerous previous sludge treatment technology studies. The identified technology approaches were screened using the criteria established in the Decision Plan, and focused bench top feasibility testing was conducted. Engineering evaluations of the costs, schedules, and technical maturity were developed and evaluated. Recommendations were developed based on technical evaluations. The criteria used in the evaluation process were as follows: (1) Safety, (2) Regulatory/stakeholder acceptance, (3) Technical maturity, (4) Operability and maintainability, (5) Life cycle cost and schedule, (6) Potential for beneficial integration with ongoing STP-Phase 1 activities, and (7) Integration with Site-wide RH-TRU processing/packaging, planning, schedule, and approach. The TEAA recommended Warm Water Oxidation (WWO) as the baseline treatment technology and two risk reduction enhancement options for further consideration during development of the process - size reduction and chemical oxidation (Fenton's reagent). The enhancement options would potentially allow a useful reduction in the total operating time required to process the K Basins sludge. The U.S. Department of Energy's Richland Field Office (DOE-RL) has approved this recommended technical approach. The baseline process can be broken down into the following main process steps: (1) STSC transfer from T Plant to the Sludge Treatment and Packaging Facility (STPF). (2) Retrieval of sludge from the STSCs and transfer to the Receipt and Reaction Tank (RRT). (3) Preparation for immobilization by oxidation using heated water (i.e., WWO) for those batches that require it and concentration by evaporating water at about atmospheric pressure in the RRT. (4) Immobilization by using additives to eliminate free liquids and packaging of the treated sludge into drums. (5) Inspection and handling of the filled drums prior to transfer to a separate storage and shipping facility. (6) Handling of vapor, condensate, and other waste streams generated by the process. Each of these steps is discussed in the paper, together with the current state of progress in developing the technology and requirements for continued development. A schematic of the recommended baseline WWO treatment process is given below. (authors)« less

Combining high-rate aerobic wastewater treatment with anaerobic digestion of waste activated sludge at a pulp and paper mill.

PubMed

Magnusson, Björn; Ekstrand, Eva-Maria; Karlsson, Anna; Ejlertsson, Jörgen

2018-05-01

The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate with a low sludge age. Two 150 L containers were used, one for aeration and one for sedimentation and sludge return. The hydraulic retention time was decreased from 24 hours to 7 hours, and the sludge age was lowered from 12 days to 2-4 days. The methane potential of the WAS was evaluated using batch tests, as well as continuous anaerobic digestion (AD) in 4 L reactors in mesophilic and thermophilic conditions. Wastewater treatment capacity was increased almost four-fold at maintained degradation efficiency. The lower sludge age greatly improved the methane potential of the WAS in batch tests, reaching 170 NmL CH 4 /g VS at a sludge age of 2 days. In addition, the continuous AD showed a higher methane production at thermophilic conditions. Thus, the combination of high-rate wastewater treatment and AD of WAS is a promising option for the pulp and paper industry.

Determination of the acute toxicities of physicochemical pretreatment and advanced oxidation processes applied to dairy effluents on activated sludge.

PubMed

Sivrioğlu, Özge; Yonar, Taner

2015-04-01

In this study, the acute toxicities of raw, physicochemical pre-treated, ozonated, and Fenton reagent applied samples of dairy wastewater toward activated sludge microorganisms, evaluated using the International Organization for Standardization's respiration inhibition test (ISO 8192), are presented. Five-day biological oxygen demand (BOD5) was measured to determine the biodegradability of physicochemical treatment, ozonation, Fenton oxidation or no treatment (raw samples) of dairy wastewater. Chemical pretreatment positively affected biodegradability, and the inhibition exhibited by activated sludge was removed to a considerable degree. Ozonation and the Fenton process exhibited good chemical oxygen demand removal (61%) and removal of toxins. Low sludge production was observed for the Fenton process applied to dairy effluents. We did not determine the inhibitory effect of the Fenton-process on the activated sludge mixture. The pollutant-removal efficiencies of the applied processes and their associated operating costs were determined. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

PubMed

Ge, Huoqing; Batstone, Damien; Keller, Jurg

2016-01-01

The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

Optimization of Ozonation Process for the Reduction of Excess Sludge Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

PubMed Central

Subha, B.; Muthukumar, M.

2012-01-01

Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (R 2) of VSS and COD reduction were 0.9689 and 0.8838, respectively. VSS reduction (81%) was achieved at acidic pH 6.9, 12 minutes ozonation, and retention time of 10 days. COD reduction (87%) was achieved at acidic pH 6.7, 8 minutes of ozonation time, and retention time of 6 days. Low ozonation time and high retention time influence maximum sludge reduction, whereas low ozonation time with low retention time was effective for COD reduction. PMID:22593666

Effects of 4-chlorophenol wastewater treatment on sludge acute toxicity, microbial diversity and functional genes expression in an activated sludge process.

PubMed

Zhao, Jianguo; Li, Yahe; Li, Yu; Yu, Zeya; Chen, Xiurong

2018-05-31

In this study, the effects of 4-chlorophenol (4-CP) wastewater treatment on sludge acute toxicity of luminescent bacteria, microbial diversity and functional genes expression of Pseudomonas were explored. Results showed that in the entire operational process, the sludge acute toxicity acclimated by 4-CP in a sequencing batch bioreactor (SBR) was significantly higher than the control SBR without 4-CP. The dominant phyla in acclimated SBR were Proteobacteria and Firmicutes, which also existed in control SBR. Some identified genera in acclimated SBR were responsible for 4-CP degradation. At the stable operational stages, the functional genes expression of Pseudomonas in acclimated SBR was down-regulated at the end of SBR cycle, and their expression mechanisms needed further research. This study provides a theoretical support to comprehensively understand the sludge performance in industrial wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improving primary treatment of urban wastewater with lime-induced coagulation.

PubMed

Marani, Dario; Ramadori, Roberto; Braguglia, Camilla Maria

2004-01-01

The enhancement of primary treatment efficiency through the coagulation process may yield several advantages, including lower aeration energy in the subsequent biological unit and higher recovery of biogas from sludge digestion. In this work sewage coagulation with lime was studied at pilot plant level, using degritted sewage from the city of Rome. The work aimed at optimising the operating conditions (coagulant dosage or treatment pH, and mixing conditions in the coagulation and flocculation tanks), in order to maximise the efficiency of suspended Chemical Oxygen Demand (COD) removal and to minimise sludge production. Lime dosage optimisation resulted in an optimal treatment pH of 9. Lime addition up to pH 9 may increase COD removal rate in the primary treatment from typical 30-35% of plain sedimentation up to 55-70%. Within the velocity gradients experimented in this work (314-795 s(-1) for the coagulation tank and 13-46 s(-1) for the flocculation tank), mixing conditions did not significantly affect the lime-enhanced process, which seems to be controlled by slow lime dissolution. Sludge produced in the lime-enhanced process settled and compacted easily, inducing an average 36% decrease in sludge volume with respect to plain settling. However excess sludge was produced, which was not accounted for by the amount of suspended solids removed. This is probably due to incomplete dissolution of lime, which may be partially incorporated in the sludge.

Review of Solids Handling. Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Carnegie, John W.

This student manual contains the textual material for a single-lesson unit which summarizes and reviews most of the solids handling processes in common use in municipal treatment plants. No attempt is made to detail the theory and operation of the processes. Topics discussed include: (1) sources of sludge; (2) the importance of sludge management;…

Application of dielectric constant measurement in microwave sludge disintegration and wastewater purification processes.

PubMed

Kovács, Petra Veszelovszki; Lemmer, Balázs; Keszthelyi-Szabó, Gábor; Hodúr, Cecilia; Beszédes, Sándor

2018-05-01

It has been numerously verified that microwave radiation could be advantageous as a pre-treatment for enhanced disintegration of sludge. Very few data related to the dielectric parameters of wastewater of different origins are available; therefore, the objective of our work was to measure the dielectric constant of municipal and meat industrial wastewater during a continuous flow operating microwave process. Determination of the dielectric constant and its change during wastewater and sludge processing make it possible to decide on the applicability of dielectric measurements for detecting the organic matter removal efficiency of wastewater purification process or disintegration degree of sludge. With the measurement of dielectric constant as a function of temperature, total solids (TS) content and microwave specific process parameters regression models were developed. Our results verified that in the case of municipal wastewater sludge, the TS content has a significant effect on the dielectric constant and disintegration degree (DD), as does the temperature. The dielectric constant has a decreasing tendency with increasing temperature for wastewater sludge of low TS content, but an adverse effect was found for samples with high TS and organic matter contents. DD of meat processing wastewater sludge was influenced significantly by the volumetric flow rate and power level, as process parameters of continuously flow microwave pre-treatments. It can be concluded that the disintegration process of food industry sludge can be detected by dielectric constant measurements. From technical purposes the applicability of dielectric measurements was tested in the purification process of municipal wastewater, as well. Determination of dielectric behaviour was a sensitive method to detect the purification degree of municipal wastewater.

Stabilization of waste-activated sludge through the anoxic-aerobic digestion process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, S.; Fujita, M.; Terai, K.

1982-08-01

During the aerobic digestion process, the nitrogen which had been embedded in the activated sludge is solubilized to form ammoniacal and nitric nitrogen which are in turn transferred to the liquor and cause the increase of nitrogen loading in the sewage treatment plant. In this study, the anoxic-aerobic sludge digestion system which is a modified form of the conventional aerobic sludge digestion is made up of aerobic and anoxic tanks and are designed to remove both the volatile suspended solids and the total nitrogen (TN) simultaneously. The removal efficiencies of both VSS and TN were investigated by feeding waste-activated sludgemore » continuously and semicontinuously. The maximum percent reduction of both VSS and TN was achieved at a Q /SUB r/ /Q /SUB s/ ratio of 2 in the continuous process. The semicontinuous process was used to improve the nitrogen removal efficiency further. In the semicontinuous process, the VSS reduction efficiency as well as the nitrogen removal efficiency increased remarkably under a constant Q /SUB r/ /Q /SUB s/ ratio of 2. This process also achieved a VSS reduction efficiency higher than the aerobic digestion process (control). It was suggested that the additional anoxic tank enhanced the sludge digestion. Furthermore, the anoxic-aerobic digestion system can be applied to other treatment media like the primary sludge, industrial sludge, animal manure, etc.« less

MiDAS: the field guide to the microbes of activated sludge.

PubMed

McIlroy, Simon Jon; Saunders, Aaron Marc; Albertsen, Mads; Nierychlo, Marta; McIlroy, Bianca; Hansen, Aviaja Anna; Karst, Søren Michael; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

2015-01-01

The Microbial Database for Activated Sludge (MiDAS) field guide is a freely available online resource linking the identity of abundant and process critical microorganisms in activated sludge wastewater treatment systems to available data related to their functional importance. Phenotypic properties of some of these genera are described, but most are known only from sequence data. The MiDAS taxonomy is a manual curation of the SILVA taxonomy that proposes a name for all genus-level taxa observed to be abundant by large-scale 16 S rRNA gene amplicon sequencing of full-scale activated sludge communities. The taxonomy can be used to classify unknown sequences, and the online MiDAS field guide links the identity to the available information about their morphology, diversity, physiology and distribution. The use of a common taxonomy across the field will provide a solid foundation for the study of microbial ecology of the activated sludge process and related treatment processes. The online MiDAS field guide is a collaborative workspace intended to facilitate a better understanding of the ecology of activated sludge and related treatment processes--knowledge that will be an invaluable resource for the optimal design and operation of these systems. © The Author(s) 2015. Published by Oxford University Press.

Interpretation of the characteristics of ocean-dumped sewage sludge related to remote sensing

NASA Technical Reports Server (NTRS)

Pagoria, P. S.; Kuo, C. Y.

1979-01-01

Wastewater sludge characteristics in general, and characteristics of wastewater sludges generated by the City of Philadelphia in particular, were addressed. The types and sources of wastewater sludges, a description of sludge treatment and disposal processes, examination of sludge generation and management for the City of Philadelphia, and definition of characteristics for typical east coast sludges undergoing ocean disposal were discussed. Specific differences exist between the characteristics of primary and secondary wastewater sludges, especially with the nature and size distribution of the solids particles. The sludges from the City of Philadelphia monitored during remote sensing experiments were mixtures of various sludge types and lacked distinguishing characteristics. In particular, the anaerobic digestion process exerted the most significant influence on sludge characteristics for the City of Philadelphia. The sludges generated by the City of Philadelphia were found to be typical and harbor no unique features.

Evaluation of energy consumption during aerobic sewage sludge treatment in dairy wastewater treatment plant.

PubMed

Dąbrowski, Wojciech; Żyłka, Radosław; Malinowski, Paweł

2017-02-01

The subject of the research conducted in an operating dairy wastewater treatment plant (WWTP) was to examine electric energy consumption during sewage sludge treatment. The excess sewage sludge was aerobically stabilized and dewatered with a screw press. Organic matter varied from 48% to 56% in sludge after stabilization and dewatering. It proves that sludge was properly stabilized and it was possible to apply it as a fertilizer. Measurement factors for electric energy consumption for mechanically dewatered sewage sludge were determined, which ranged between 0.94 and 1.5 kWhm -3 with the average value at 1.17 kWhm -3 . The shares of devices used for sludge dewatering and aerobic stabilization in the total energy consumption of the plant were also established, which were 3% and 25% respectively. A model of energy consumption during sewage sludge treatment was estimated according to experimental data. Two models were applied: linear regression for dewatering process and segmented linear regression for aerobic stabilization. The segmented linear regression model was also applied to total energy consumption during sewage sludge treatment in the examined dairy WWTP. The research constitutes an introduction for further studies on defining a mathematical model used to optimize electric energy consumption by dairy WWTPs. Copyright © 2016 Elsevier Inc. All rights reserved.

Distribution and persistence of fecal bacterial populations in liquid and dewatered sludge from a biological treatment plant.

PubMed

Vilanova, Xavier; Blanch, Anicet R

2005-12-01

The changes in composition and structure of fecal coliforms (FC) and enterococci (ENT) populations, as well as the elimination of spores of sulphite-reducing bacteria (SRB), were compared between municipal sewage and their derived sludge in a biological treatment plant in order to determine any selective reduction or adsorption to sludge during the treatment process. Additionally, the persistence of antibiotic-resistant enterococcal populations in two kinds of sludge was also considered to evaluate their potential elimination in the treatment process. Microbial indicators, vancomycin-resistant and erythromycin-resistant enterococci were enumerated. The structure and composition of FC and ENT populations were determined by biochemical fingerprinting and clustering analyses. Raw and treated sewage showed a concentration of FC 1 log unit higher than ENT and nearly 2 log units higher than spores of SRB. However, the three studied indicators showed similar concentrations in both types of sludge. Consequently, FC were eliminated in higher proportion than ENT and spores of SRB in sludge. FC and ENT populations showed high diversity and similarity population indexes for all kinds of samples. Antibiotic-resistant enterococci persisted in a similar proportion in respect to total enterococci not only in treated sewage but also in sludge. The persistence of antibiotic-resistant strains in sludge as well as in treated sewage should be considered if they are used for land disposal or for water reutilization, respectively.

Treatment of winery wastewater in a conventional municipal activated sludge process: five years of experience.

PubMed

Bolzonella, D; Zanette, M; Battistoni, P; Cecchi, F

2007-01-01

A full-scale wastewater treatment plant where municipal and winery wastewaters were co-treated was studied for five years. The experimental results showed that suspended solids, COD, nitrogen and phosphorous were effectively removed both during the treatment of municipal wastewater and the cotreatment of municipal and winery wastewater. The sludge production increase from 4 tons to 5.5 tons per day during the harvesting and wine making period. In any case the specific sludge production was 0.2 kgMLVSS per kgCOD(removed) despite the organic loading increasing. About 70% of the COD was removed through respiration. Also the energy demand increased from 6,000 to 7,000 kWh per day. The estimated costs for the treatment of the winery wastewater was 0.2-0.3 Euros per m3 of treated wastewater. With reference to the process efficiency, the nitrogen removal was just 20%. The co-treatment of municipal and winery wastewater in conventional activated sludge processes can be a feasible solution for the treatment of these streams at relatively low costs.

Occurrence, distribution, and potential influencing factors of sewage sludge components derived from nine full-scale wastewater treatment plants of Beijing, China.

PubMed

Wang, Xu; Li, Meiyan; Liu, Junxin; Qu, Jiuhui

2016-07-01

Millions of tons of waste activated sludge (WAS) produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants (WWTPs) of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples (up to 9478mg/L), followed by endogenous residues (6736mg/L), extracellular polymeric substances (2088mg/L), and intracellular storage products (464mg/L) among others. Moreover, significant differences (p<0.05) were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge. Copyright © 2016. Published by Elsevier B.V.

Anaerobic storage as a pretreatment for enhanced biodegradability of dewatered sewage sludge.

PubMed

Xu, Huacheng; He, Pinjing; Wang, Guanzhao; Shao, Liming; Lee, Duujong

2011-01-01

Dewatered sewage sludge is often stored still before further processing and final disposal. This study showed that anaerobic storage of dewatered sewage sludge could hydrolyze organic matter from the sludge matrix, and increase soluble organic acid content from 90 to 2400 mg/L and soluble organic carbon content from 220 to 1650 mg/L. Correspondingly, the contents of proteins, celluloses and hemicelluloses were reduced by 2-9%. Applying anaerobic storage markedly enhanced the efficiency of the subsequent bio-drying process on stored sludge. Correspondingly, biogas and odor gas were produced immediately after commencing the sludge storage. Anaerobic storage with odor control can be applied as a pretreatment process for dewatered sewage sludge in wastewater treatment plants. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Research on the treatment of wastewater containing PVA by ozonation-activated sludge process].

PubMed

Xing, Xiao-Qiong; Huang, Cheng-Lan; Liu, Min; Chen, Ying

2012-11-01

The wastewater containing polyvinyl alcohol (PVA) was characterized with poor biodegradability, and was difficult to remove. In order to find an economically reasonable and practical technology, the research on the removal efficiency of different concentration wastewater containing PVA by ozonation-activated sludge process was studied, and the result was compared with the traditional activated sludge process. The results showed that the ozonation-activated sludge process was not suitable for treating influent with COD below 500 mg x L(-1) and the wastewater PVA concentration was 10-30 mg x L(-1). When the influent COD was between 500-800 mg x L(-1) and the PVA concentration was 15-60 mg x L(-1), the system had advantages on dealing with this kind of wastewater, and the average removal efficiency of COD and PVA were 92.8% and 57.4%, which were better than the traditional activated sludge process 4.1% and 15.2% respectively. In addition, the effluent concentrations of COD could keep between 30-60 mg x L(-1). When the influent COD was 1 000-1 200 mg x L(-1) and the PVA concentration was 20-70 mg x L(-1), the average removal efficiencies of COD and PVA were 90.9% and 45.3%, which were better than the traditional activated sludge process 12.8% and 12.1% respectively, but the effluent should to be further treated. Compared with the traditional activated sludge process, ozonation-activated sludge process had high treatment efficiency, stable running effect, and effectively in dealing with industrial wastewater containing PVA.

Use of anaerobic hydrolysis pretreatment to enhance ultrasonic disintegration of excess sludge.

PubMed

Li, Xianjin; Zhu, Tong; Shen, Yang; Chai, Tianyu; Xie, Yuanhua; You, Meiyan; Wang, Youzhao

2016-01-01

To improve the excess sludge disintegration efficiency, reduce the sludge disintegration cost, and increase sludge biodegradability, a combined pretreatment of anaerobic hydrolysis (AH) and ultrasonic treatment (UT) was proposed for excess sludge. Results showed that AH had an advantage in dissolving flocs, modifying sludge characteristics, and reducing the difficulty of sludge disintegration, whereas UT was advantageous in damaging cell walls, releasing intracellular substances, and decomposing macromolecular material. The combined AH-UT process was an efficient method for excess sludge pretreatment. The optimized solution involved AH for 3 days, followed by UT for 10 min. After treatment, chemical oxygen demand, protein, and peptidoglycan concentrations reached 3,949.5 mg O2/L, 752.5 mg/L and 619.1 mg/L, respectively. This work has great significance for further engineering applications, namely, reducing energy consumption, increasing the sludge disintegration rate, and improving the biochemical properties of sludge.

Reduction of excess sludge production using mechanical disintegration devices.

PubMed

Strünkmann, G W; Müller, J A; Albert, F; Schwedes, J

2006-01-01

The usability of mechanical disintegration techniques for the reduction of excess sludge production in the activated sludge process was investigated. Using three different disintegration devices (ultrasonic homogeniser, stirred media mill, high pressure homogeniser) and different operational parameters of the disintegration, the effect of mechanical disintegration on the excess sludge production and on the effluent quality was studied within a continuously operated, laboratory scale wastewater treatment system with pre-denitrification. Depending on the operational conditions and the disintegration device used, a reduction of excess sludge production of up to 70% was achieved. A combination of mechanical disintegration with a membrane bioreactor process with high sludge age is more energy effective concerning reduction of sludge production than with a conventional activated sludge process at lower sludge ages. Depending on the disintegration parameters, the disintegration has no, or only minor, negative effect on the soluble effluent COD and on the COD-removal capacity of the activated sludge process. Nitrogen-removal was slightly deteriorated by the disintegration, whereas the system used was not optimised for nitrogen removal before disintegration was implemented.

Influence of mechanical disintegration on the microbial growth of aerobic sludge biomass: A comparative study of ultrasonic and shear gap homogenizers by oxygen uptake measurements.

PubMed

Divyalakshmi, P; Murugan, D; Sivarajan, M; Saravanan, P; Lajapathi Rai, C

2015-11-01

Wastewater treatment plant incorporates physical, chemical and biological processes to treat and remove the contaminants. The main drawback of conventional activated sludge process is the huge production of excess sludge, which is an unavoidable byproduct. The treatment and disposal of excess sludge costs about 60% of the total operating cost. The ideal way to reduce excess sludge production during wastewater treatment is by preventing biomass formation within the aerobic treatment train rather than post treatment of the generated sludge. In the present investigation two different mechanical devices namely, Ultrasonic and Shear Gap homogenizers have been employed to disintegrate the aerobic biomass. This study is intended to restrict the multiplication of microbial biomass and at the same time degrade the organics present in wastewater by increasing the oxidative capacity of microorganisms. The disintegrability on biomass was determined by biochemical methods. Degree of inactivation provides the information on inability of microorganisms to consume oxygen upon disruption. The soluble COD quantifies the extent of release of intra cellular compounds. The participation of disintegrated microorganism in wastewater treatment process was carried out in two identical respirometeric reactors. The results show that Ultrasonic homogenizer is very effective in the disruption of microorganisms leading to a maximum microbial growth reduction of 27%. On the other hand, Shear gap homogenizer does not favor the sludge growth reduction rather it facilitates the growth. This study also shows that for better microbial growth reduction, floc size reduction alone is not sufficient but also microbial disruption is essential. Copyright © 2015 Elsevier Inc. All rights reserved.

Behavior, fate, and mass loading of short chain chlorinated paraffins in an advanced municipal sewage treatment plant.

PubMed

Zeng, Lixi; Li, Huijuan; Wang, Thanh; Gao, Yan; Xiao, Ke; Du, Yuguo; Wang, Yawei; Jiang, Guibin

2013-01-15

Sewage treatment plants (STP) are an important source of short chain chlorinated paraffins (SCCPs) to the ambient environment through discharge of effluent and application of sludge. In this work, a field study was conducted to determine the behavior and possible removal of SCCPs during the sewage treatment process in an advanced municipal STP in Beijing, China. SCCPs were detected in all sewage water and sludge samples, and 97% of the initial mass loading in raw sewage was found to be associated with suspended matter. The total concentrations in raw influent, tertiary effluent, and dewatered sludge were 184 ± 19 ng/L, 27 ± 6 ng/L, and 15.6 ± 1.4 μg/g dry weight (d.w.), respectively. The dissolved concentrations of total SCCPs (∑SCCPs) significantly decreased during mechanical, biological, and chemical treatments. SCCP homologue profiles in aqueous phase were distinctly different from those in solid phase. Along the treatment process, the relative abundance of shorter chain and lower chlorinated congeners gradually increased in sewage water, but no obvious variations of homologue profiles were found in sludge. Mass flow analysis indicated, the removal efficiency in aqueous phase for ∑SCCPs was 82.2%, and the congener-specific removal efficiencies were positively related to their solid-water partition coefficients (K(d)). Mass balance results indicated that 0.8% and 72.6% of the initial SCCP mass loading were ultimately found in the effluents and dewatered sludge, respectively, while the remaining 26.6% was lost mainly due to biodegradation/biotransformation. It was suggested that the activated sludge system including basic anaerobic-anoxic-aerobic processes played an effective role in removing SCCPs from the wastewater, while the sorption to sludge by hydrophobic interactions was an important fate of SCCPs during the sewage treatment.

Predicting the drying properties of sludge based on hydrothermal treatment under subcritical conditions.

PubMed

Mäkelä, Mikko; Fraikin, Laurent; Léonard, Angélique; Benavente, Verónica; Fullana, Andrés

2016-03-15

The effects of hydrothermal treatment on the drying properties of sludge were determined. Sludge was hydrothermally treated at 180-260 °C for 0.5-5 h using NaOH and HCl as additives to influence reaction conditions. Untreated sludge and attained hydrochar samples were then dried under identical conditions with a laboratory microdryer and an X-ray microtomograph was used to follow changes in sample dimensions. The effective moisture diffusivities of sludge and hydrochar samples were determined and the effect of process conditions on respective mean diffusivities evaluated using multiple linear regression. Based on the results the drying time of untreated sludge decreased from approximately 80 min to 37-59 min for sludge hydrochar. Drying of untreated sludge was governed by the falling rate period where drying flux decreased continuously as a function of sludge moisture content due to heat and mass transfer limitations and sample shrinkage. Hydrothermal treatment increased the drying flux of sludge hydrochar and decreased the effect of internal heat and mass transfer limitations and sample shrinkage especially at higher treatment temperatures. The determined effective moisture diffusivities of sludge and hydrochar increased as a function of decreasing moisture content and the mean diffusivity of untreated sludge (8.56·10(-9) m(2) s(-1)) and sludge hydrochar (12.7-27.5·10(-9) m(2) s(-1)) were found statistically different. The attained regression model indicated that treatment temperature governed the mean diffusivity of hydrochar, as the effects of NaOH and HCl were statistically insignificant. The attained results enabled prediction of sludge drying properties through mean moisture diffusivity based on hydrothermal treatment conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hot-isostatically pressed wasteforms for Magnox sludge immobilisation

NASA Astrophysics Data System (ADS)

Heath, Paul G.; Stewart, Martin W. A.; Moricca, Sam; Hyatt, Neil C.

2018-02-01

Thermal treatment technologies offer many potential benefits for the treatment of radioactive wastes including the passivation of reactive species and significant waste volume reductions. This paper presents a study investigating the production of wasteforms using Hot-isostatic pressing technology for the immobilisation of Magnox sludges from the UK's Sellafield Site. Simulants considered physically representative of these sludges were used to determine possible processing parameters and to determine the phase assemblages and morphologies produced during processing. The study showed hot-isostatic pressing is capable of processing Magnox sludges at up to 60 wt% (oxide basis) into dense, mixed ceramic wasteforms. The wasteforms produced are a glass-bonded ceramic of mixed magnesium titanates, encapsulating localised grains of periclase. The ability to co-process Magnox sludges with SIXEP sand/clinoptilolite slurries has also been demonstrated. The importance of these results is presented through a comparison of volume reduction data, which shows HIPing may provide a 20-fold volume reduction over the current cementitious baseline and double the volume reduction attainable for vitrification technologies.

A Guide for Developing Standard Operating Job Procedures for the Activated Sludge - Aeration & Sedimentation Process Wastewater Treatment Facility. SOJP No. 5.

ERIC Educational Resources Information Center

Mason, George J.

This guide for developing standard operating job procedures for wastewater treatment facilities is devoted to the activated sludge aeration and sedimentation process. This process is for conversion of nonsettleable and nonfloatable materials in wastewater to settleable, floculated biological groups and separation of the settleable solids from the…

A Guide for Developing Standard Operating Job Procedures for the Digestion Process Wastewater Treatment Facility. SOJP No. 10.

ERIC Educational Resources Information Center

Schwing, Carl M.

This guide describes standard operating job procedures for the digestion process of wastewater treatment facilities. This process is for reducing the volume of sludge to be treated in subsequent units and to reduce the volatile content of sludge. The guide gives step-by-step instructions for pre-startup, startup, continuous operating, shutdown,…

Sequential anaerobic-aerobic biological treatment of colored wastewaters: case study of a textile dyeing factory wastewater.

PubMed

Abiri, Fardin; Fallah, Narges; Bonakdarpour, Babak

2017-03-01

In the present study the feasibility of the use of a bacterial batch sequential anaerobic-aerobic process, in which activated sludge was used in both parts of the process, for pretreatment of wastewater generated by a textile dyeing factory has been considered. Activated sludge used in the process was obtained from a municipal wastewater treatment plant and adapted to real dyeing wastewater using either an anaerobic-only or an anaerobic-aerobic process over a period of 90 days. The use of activated sludge adapted using the anaerobic-aerobic process resulted in a higher overall decolorization efficiency compared to that achieved with activated sludge adapted using the anaerobic-only cycles. Anaerobic and aerobic periods of around 34 and 22 hours respectively resulted in an effluent with chemical oxygen demand (COD) and color content which met the standards for discharge into the centralized wastewater treatment plant of the industrial estate in which the dyeing factory was situated. Neutralization of the real dyeing wastewater and addition of carbon source to it, both of which results in significant increase in the cost of the bacterial treatment process, was not found to be necessary to achieve the required discharge standards.

Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

PubMed

Mackie, Allison L; Walsh, Margaret E

2015-11-15

The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of CKD-HDS sludge. The results of this study suggest that solids loading is a significant factor in increased sludge density found with the HDS process compared to conventional lime precipitation-sedimentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Critical operational parameters for zero sludge production in biological wastewater treatment processes combined with sludge disintegration.

PubMed

Yoon, Seong-Hoon; Lee, Sangho

2005-09-01

Mathematical models were developed to elucidate the relationships among process control parameters and the effect of these parameters on the performance of anoxic/oxic biological wastewater processes combined with sludge disintegrators (A/O-SD). The model equations were also applied for analyses of activated sludge processes hybrid with sludge disintegrators (AS-SD). Solubilization ratio of sludge in the sludge disintegrator, alpha, hardly affected sludge reduction efficiencies if the biomass was completely destructed to smaller particulates. On the other hand, conversion efficiency of non-biodegradable particulates to biodegradable particulates, beta, significantly affected sludge reduction efficiencies because beta was directly related to the accumulation of non-biodegradable particulates in bioreactors. When 30% of sludge in the oxic tank was disintegrated everyday and beta was 0.5, sludge reduction was expected to be 78% and 69% for the A/O-SD and AS-SD processes, respectively. Under this condition, the sludge disintegration number (SDN), which is the amount of sludge disintegrated divided by the reduced sludge, was calculated to be around 4. Due to the sludge disintegration, live biomass concentration decreased while other non-biodegradable particulates concentration increased. As a consequence, the real F/M ratio was expected to be much higher than the apparent F/M. The effluent COD was maintained almost constant for the range of sludge disintegration rate considered in this study. Nitrogen removal efficiencies of the A/O-SD process was hardly affected by the sludge disintegration until daily sludge disintegration reaches 40% of sludge in the oxic tank. Above this level of sludge disintegration, autotrophic biomass concentration decreases overly and TKN in the effluent increases abruptly in both the A/O-SD and AS-SD processes. Overall, the trends of sludge reduction and effluent quality according to operation parameters matched well with experimental results found in literatures.

REVISING/UPDATING EPA 625/1-79-011, PROCESS DESIGN MANUAL FOR SLUDGE TREATMENT AND DISPOSAL

EPA Science Inventory

The US Environmental Protection Agency (EPA) wishes to revise/update its very large and comprehensive 1979 Process Design Manual for Sludge Treatment and Disposal, EPA 625/1-79-011. As you might imagine the task is not trivial, as already in 1979 the original manual cost more tha...

Utilisation of energy from digester gas and sludge incineration at Hamburg's Köhlbrandhöft WWTP.

PubMed

Thierbach, R D; Hanssen, H

2002-01-01

At Hamburg's Köhlbrandhöft WWTP the demand for external energy supply is minimised by state of the art sludge treatment. The sludge is subjected to thickening, anaerobic digestion, dewatering, drying and incineration. The digester gas is used in a combined gas and steam turbine process. The sludge incineration also produces steam, which is also used in the steam turbine that follows the gas turbine. The turbines produce electricity, partially expanded steam is used for the sludge drying process. Heat from the condensation of vapours from sludge drying is used to heat the anaerobic digesters. The overall process requires no external heat or fuel and produces 60% of the WWTP's electricity demand.

Environmental application for GIS: Assessing Iskandar Malaysia's (IM) sewage sludge for potential biomass resource

NASA Astrophysics Data System (ADS)

Salim, M. R.; Shaharuddin, N.; Abdullah Halim, K.

2014-02-01

The low carbon scenario could be achieved through the identification of major sectors contributing to the emission of high greenhouse gases (GHG) into the atmosphere. Sewage treatment plant (STP) was ranked as one of the major sectors that emits methane gas (CH4) during treatment processes, including sludge treatment. Sludge treatment is also capital extensive with high operational cost. Thus, sewage sludge has been accepted as a nuisance in STP. However, many has claimed that, sludge produced contain organic matter that has the potential for biomass resource. Thus, it would be such a Žwaste? if sludge are directly disposed of into the landfill without utilizing them at its full potential. In order to do so, it is vital to be able to determine the amount of sludge production. This research was implemented in Iskandar Malaysia regions in the state of Johor. By using GIS tool, the regions that produced the most sewage sludge can be determined, and can be group as critical area. Result shows that Nusajaya produces the most, compared to other regions, which indicated Nusajaya as a densely populated region.

Extracellular protein analysis of activated sludge and their functions in wastewater treatment plant by shotgun proteomics.

PubMed

Zhang, Peng; Shen, Yu; Guo, Jin-Song; Li, Chun; Wang, Han; Chen, You-Peng; Yan, Peng; Yang, Ji-Xiang; Fang, Fang

2015-07-10

In this work, proteins in extracellular polymeric substances extracted from anaerobic, anoxic and aerobic sludges of wastewater treatment plant (WWTP) were analyzed to probe their origins and functions. Extracellular proteins in WWTP sludges were identified using shotgun proteomics, and 130, 108 and 114 proteins in anaerobic, anoxic and aerobic samples were classified, respectively. Most proteins originated from cell and cell part, and their most major molecular functions were catalytic activity and binding activity. The results exhibited that the main roles of extracellular proteins in activated sludges were multivalence cations and organic molecules binding, as well as in catalysis and degradation. The catalytic activity proteins were more widespread in anaerobic sludge compared with those in anoxic and aerobic sludges. The structure difference between anaerobic and aerobic sludges could be associated with their catalytic activities proteins. The results also put forward a relation between the macro characteristics of activated sludges and micro functions of extracellular proteins in biological wastewater treatment process.

Distribution, partition and removal of polycyclic aromatic hydrocarbons (PAHs) during coking wastewater treatment processes.

PubMed

Zhang, Wanhui; Wei, Chaohai; An, Guanfeng

2015-05-01

In this study, we report the performance of a full-scale conventional activated sludge (A-O1-O2) treatment in eliminating polycyclic aromatic hydrocarbons (PAHs). Both aqueous and solid phases along with the coking wastewater treatment processes were analyzed for the presence of 18 PAHs. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent and sludge samples. In the coking wastewater treatment system, 4-5 ring PAHs were the dominant compounds, while 4 rings PAHs predominated in the sludge samples. Over 98% of the PAH removal was achieved in the coking wastewater treatment plant (WWTP), with the total concentration of PAHs being 21.3 ± 1.9 μg L(-1) in the final effluent. During the coking wastewater treatment processes, the association of the lower molecular weight PAH with suspended solids was generally less than 60%, while the association of higher molecular weight PAHs was greater than 90%. High distribution efficiencies (Kdp and Kds) were found, suggesting that adsorption was the potential removal pathway of PAHs. Finally, the mass balances of PAHs in various stages of the coking WWTP were obtained, and the results indicated that adsorption to sludge was the main removal pathway for PAHs in the coking wastewater treatment processes.

Economic feasibility of irradiation-composting plant of sewage sludge

NASA Astrophysics Data System (ADS)

Hashimoto, S.; Nishimura, K.; Machi, S.

Design and cost analysis were made for a sewage sludge treatment plant (capacity 25 - 200 ton sludge/day) with an electron accelerator. Dewatered sludge is spreaded on a rolling drum through a flat nozzle and disinfected by electron irradiation with a dose of 5 kGy. Composting of the irradiated sludge is also made at the optimum temperature for 3 days. The accelerating voltage of electron and capacity of the accelerator are 1.5 MV and 15 kW, respectively. Total volume of the fermentor is about one third of that of conventional composting process because the irradiation makes the time of composting shorter. The cost of sludge treatment is almost the same as that of conventional method.

The use of waterworks sludge for the treatment of vegetable oil refinery industry wastewater.

PubMed

Basibuyuk, M; Kalat, D G

2004-03-01

Water treatment works using coagulation/flocculation in the process stream will generate a waste sludge. This sludge is termed as ferric, alum, or lime sludge based on which coagulant was primarily used. The works in Adana, Turkey uses ferric chloride. The potential for using this sludge for the treatment of vegetable oil refinery industry wastewater by coagulation has been investigated. The sludge acted as a coagulant and excellent oil and grease, COD and TSS removal efficiencies were obtained. The optimum conditions were a pH of 6 and a sludge dose of 1100 mg SS l(-1). The efficiency of sludge was also compared with alum and ferric chloride for the vegetable oil refinery wastewater. At doses of 1300-1900 mg SS l(-1), the sludge was as effective as ferric chloride and alum at removing oil and grease, COD, and TSS. In addition, various combinations of ferric chloride and waterworks sludge were also examined. Under the condition of 12.5 mg l(-1) fresh ferric chloride and 1000 mg SS l(-1) sludge dose, 99% oil and grease 99% TSS and 83% COD removal efficiencies were obtained.

Towards energy positive wastewater treatment by sludge treatment using free nitrous acid.

PubMed

Wang, Qilin; Hao, Xiaodi; Yuan, Zhiguo

2016-02-01

Free nitrous acid (FNA i.e. HNO2) was revealed to be effective in enhancing biodegradability of secondary sludge. Also, nitrite-oxidizing bacteria were found to be more susceptible to FNA than ammonium-oxidizing bacteria. Based on these findings, a novel FNA-based sludge treatment technology is proposed to enhance energy recovery from wastewater/sludge. Energy analysis indicated that the FNA-based technology would make wastewater treatment become an energy generating process (yielding energy at 4 kWh/PE/y; kWh/PE/y: kilowatt hours per population equivalent per year), rather than being a large energy consumer that it is today (consuming energy at 24 kWh/PE/y). Importantly, FNA required for the sludge treatment could be produced as a by-product of wastewater treatment. This proposed FNA-based technology is economically and environmentally attractive, and can be easily implemented in any wastewater treatment plants. It only involves the installation of a simple sludge mixing tank. This article presents the concept of the FNA-based technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

NASA Astrophysics Data System (ADS)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Analysis of the combustion and pyrolysis of dried sewage sludge by TGA and MS.

PubMed

Magdziarz, Aneta; Werle, Sebastian

2014-01-01

In this study, the combustion and pyrolysis processes of three sewage sludge were investigated. The sewage sludge came from three wastewater treatment plants. Proximate and ultimate analyses were performed. The thermal behaviour of studied sewage sludge was investigated by thermogravimetric analysis with mass spectrometry (TGA-MS). The samples were heated from ambient temperature to 800 °C at a constant rate 10 °C/min in air (combustion process) and argon flows (pyrolysis process). The thermal profiles presented in form of TG/DTG curves were comparable for studied sludges. All TG/DTG curves were divided into three stages. The main decomposition of sewage sludge during the combustion process took place in the range 180-580 °C with c.a. 70% mass loss. The pyrolysis process occurred in lower temperature but with less mass loss. The evolved gaseous products (H2, CH4, CO2, H2O) from the decomposition of sewage sludge were identified on-line. Copyright © 2013 Elsevier Ltd. All rights reserved.

The sludge loading rate regulates the growth and release of heterotrophic bacteria resistant to six types of antibiotics in wastewater activated sludge.

PubMed

Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

2015-01-01

Wastewater treatment plants are considered as hot reservoirs of antimicrobial resistance. However, the fates of antibiotic-resistant bacteria during biological treatment processes and relevant influencing factors have not been fully understood. This study evaluated the effects of the sludge loading rate on the growth and release of six kinds of antibiotic-resistant bacteria in an activated sludge system. The results indicated that higher sludge loading rates amplified the growth of all six types of antibiotic resistant bacteria. The release of most antibiotic-resistant bacteria through both the effluent and biosolids was amplified with increased sludge loading rate. Biosolids were the main pattern for all antibiotic-resistant bacteria release in an activated sludge system, which was determined primarily by their growth in the activated sludge. A higher sludge loading rate reactor tended to retain more antibiotic resistance. An activated sludge system with lower sludge loading rates was considered more conducive to the control of antibiotic resistance.

Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic–Anoxic–Aerobic Activated Sludge System

PubMed Central

Zeng, Qingling; Li, Yongmei; Yang, Shijia

2013-01-01

Abstract Estrogen in wastewater are responsible for a significant part of the endocrine-disrupting effects observed in the aquatic environment. The effect of sludge retention time (SRT) on the removal and fate of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in an anaerobic–anoxic–oxic activated sludge system designed for nutrient removal was investigated by laboratory-scale experiments using synthetic wastewater. With a hydraulic retention time of 8 h, when SRT ranged 10–25 days, E2 was almost completely removed from water, and EE2 removal efficiency was 65%–81%. Both estrogens were easily sorbed onto activated sludge. Distribution coefficients (Kd) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%–80.1% was biodegraded; 18.9%–34.7% was released in effluent; and 0.88%–3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants. PMID:23633892

Fate of heavy metals and major nutrients in a sludge-soil-plant-leachate system during the sludge phyto-treatment process.

PubMed

Xu, Tianfen; Qiu, Jinrong; Wu, Qi-Tang; Guo, Xiaofang; Wei, Zebin; Xie, Fangwen; Wong, Jonathan W C

2013-01-01

Land application of sewage sludge usually leads to increased levels of heavy metals in soil, plants and groundwater. Pre-treatment using plants has been proposed to reduce the contents of heavy metals and water in sludge prior to land application. This study quantified the transfer of Zn, Cd, Pb and major nutrients in a sludge-soil-plant-leachate system during the treatment of sewage sludge. To accomplish this, a two year pot experiment was carried out to collect leachate, mono- and co-cropping of Sedum alfredii and feed crops was conducted in sludge with an under-layer soil support. Sludge phyto-treatment increased Zn and Cd concentrations in the under-layer soil, but not Pb. Specifically, 70%, 70% and 80% of the original Zn, Cd and Pb, respectively, remained in the sludge, while about 40%, 70% and 60% of the original N, P and K remained. Only 3% to 5% of Cd and Zn and < 1% of Pb were transferred into the under-layer soils or leachates, while more than 12% of the N and P were transferred. Co-planting S. alfredii and feed crops led to a significant reduction of heavy metals in leachates when compared with sludge without planting. Overall, sludge leachate is more appropriate than whole sludge for recycling in agriculture since it reduces the chance of heavy metal contamination in the agro-ecosystem; therefore, co-cropping phytotreatment of sludge can be coupled with sludge leachate recycling for crop production and re-collection of the sludge residue for landfilling.

Fermentation and chemical treatment of pulp and paper mill sludge

DOEpatents

Lee, Yoon Y; Wang, Wei; Kang, Li

2014-12-02

A method of chemically treating partially de-ashed pulp and/or paper mill sludge to obtain products of value comprising taking a sample of primary sludge from a Kraft paper mill process, partially de-ashing the primary sludge by physical means, and further treating the primary sludge to obtain the products of value, including further treating the resulting sludge and using the resulting sludge as a substrate to produce cellulase in an efficient manner using the resulting sludge as the only carbon source and mixtures of inorganic salts as the primary nitrogen source, and including further treating the resulting sludge and using the resulting sludge to produce ethanol.

The effect of different mesophilic temperatures during anaerobic digestion of sludge on the overall performance of a WWTP in Sweden.

PubMed

Moestedt, J; Rönnberg, J; Nordell, E

2017-12-01

This project was initiated to evaluate the effect of alternative process temperatures to 38 °C at the anaerobic digestion step in a Swedish wastewater treatment plant (WWTP) treating mixed sludge. The efficiency of the different temperatures was evaluated with respect to biogas production, volume of sludge produced and nutrient content in the reject water to find the optimum temperature for the WWTP as a whole. Three temperatures, 34 °C, 38 °C and 42 °C, were compared in laboratory scale. Increasing the process temperature to 42 °C resulted in process instability, reduced methane yield, accumulation of volatile fatty acids and higher treatment costs of the reject water. By decreasing the temperature to 34 °C, slightly higher sludge mass was observed and a lower gas production rate, while the specific methane produced remained unchanged compared to 38 °C but foaming was observed at several occasions. In summary 38 °C was proved to be the most favourable temperature for the anaerobic digestion process treating mixed sludge when the evaluation included effects such as foaming, sludge mass and quality of the reject water.

Irradiation of municipal sludge for agricultural use

NASA Astrophysics Data System (ADS)

Ahlstrom, Scott B.

Research has demonstrated that irradiation is an effective means for reducing pathogens in sewage sludge to levels where sludge reuse in public areas meets criteria for protection of the public health. Complementary research has demonstrated the value of the irradiated sludge in both agronomic and animal science applications. The benefits of sludge application to cropland are well documented. The irradiation process does not increase the extractability and plant uptake of a broad range of nutrients and heavy metals from sludge-amended soils. However, it does eliminate the hazards associated with pathogen contamination when applying sludge to agricultural land. Irradiated sludge has also been evaluated as a supplemental foodstuff for cattle and sheep. The data indicate that products derived from raw sewage may have a substantial nutritive value for ruminant animals. Irradiation of sewage sludge is a practical means of sludge disinfection. Where a highly disinfected sludge is required, it should be considered as a viable sludge management alternative. Evaluation of sludge irradiation technology and its associated costs must be done with consideration of other sludge treatment processes to develop an acceptable sludge management system.

MiDAS: the field guide to the microbes of activated sludge

PubMed Central

McIlroy, Simon Jon; Saunders, Aaron Marc; Albertsen, Mads; Nierychlo, Marta; McIlroy, Bianca; Hansen, Aviaja Anna; Karst, Søren Michael; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

2015-01-01

The Microbial Database for Activated Sludge (MiDAS) field guide is a freely available online resource linking the identity of abundant and process critical microorganisms in activated sludge wastewater treatment systems to available data related to their functional importance. Phenotypic properties of some of these genera are described, but most are known only from sequence data. The MiDAS taxonomy is a manual curation of the SILVA taxonomy that proposes a name for all genus-level taxa observed to be abundant by large-scale 16 S rRNA gene amplicon sequencing of full-scale activated sludge communities. The taxonomy can be used to classify unknown sequences, and the online MiDAS field guide links the identity to the available information about their morphology, diversity, physiology and distribution. The use of a common taxonomy across the field will provide a solid foundation for the study of microbial ecology of the activated sludge process and related treatment processes. The online MiDAS field guide is a collaborative workspace intended to facilitate a better understanding of the ecology of activated sludge and related treatment processes—knowledge that will be an invaluable resource for the optimal design and operation of these systems. Database URL: http://www.midasfieldguide.org PMID:26120139

Lab Procedures. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Carnegie, John W.

Laboratory tests used to determine status and to evaluate and/or maintain process control of the various sludge treatment processes are introduced in this lesson. Neither detailed test procedures nor explanations of how the tests should be applied to every unit are explained; this information is provided in other modules. The instructor's manual…

Improving the compression dewatering of sewage sludge through bioacidification conditioning driven by Acidithiobacillus ferrooxidans: dewatering rate vs. dewatering extent.

PubMed

Lu, Yi; Zhang, Chunmei; Zheng, Guanyu; Zhou, Lixiang

2018-04-22

Prior to mechanical dewatering, sludge conditioning is indispensable to reduce the difficulty of sludge treatment and disposal. The effect of bioacidification conditioning driven by Acidithiobacillus ferrooxidans LX5 on the dewatering rate and extent of sewage sludge during compression dewatering process was investigated in this study. The results showed that the bioacidification of sludge driven by A. ferrooxidans LX5 simultaneously improved both the sludge dewatering rate and extent, which was not attained by physical/chemical conditioning approaches, including ultrasonication, microwave, freezing/thawing, or by adding the chemical conditioner cationic polyacrylamide (CPAM). During the bioacidification of sludge, the decrease in sludge pH induced the damage of sludge microbial cell structures, which enhanced the dewatering extent of sludge, and the added Fe 2+ and the subsequent bio-oxidized Fe 3+ effectively flocculated the damaged sludge flocs to improve the sludge dewatering rate. In the compression dewatering process consisting of filtration and expression stages, high removal of moisture and a short dewatering time were achieved during the filtration stage and the expression kinetics were also improved because of the high elasticity of sludge cake and the rapid creeping of the aggregates within the sludge cake. In addition, the usefulness of bioacidification driven by A. ferrooxidans LX5 in improving the compression dewatering of sewage sludge could not be attained by the chemical treatment of sludge through pH modification and Fe 3+ addition. Therefore, the bioacidification of sludge driven by A. ferrooxidans LX5 is an effective conditioning method to simultaneously improve the rate and extent of compression dewatering of sewage sludge.

PROCESS DESIGN MANUAL: LAND APPLICATION OF SEWAGE SLUDGE AND DOMESTIC SEPTAGE

EPA Science Inventory

Land application of sewage sludge generated by domestic sewage treatment is performed in an environmentally safe and cost–effective manner in many communities. Land application involves taking advantage of the fertilizing and soil conditioning properties of sewage sludge by sp...

Identifying energy and carbon footprint optimization potentials of a sludge treatment line with Life Cycle Assessment.

PubMed

Remy, C; Lesjean, B; Waschnewski, J

2013-01-01

This study exemplifies the use of Life Cycle Assessment (LCA) as a tool to quantify the environmental impacts of processes for wastewater treatment. In a case study, the sludge treatment line of a large wastewater treatment plant (WWTP) is analysed in terms of cumulative energy demand and the emission of greenhouse gases (carbon footprint). Sludge treatment consists of anaerobic digestion, dewatering, drying, and disposal of stabilized sludge in mono- or co-incineration in power plants or cement kilns. All relevant forms of energy demand (electricity, heat, chemicals, fossil fuels, transport) and greenhouse gas emissions (fossil CO(2), CH(4), N(2)O) are accounted in the assessment, including the treatment of return liquor from dewatering in the WWTP. Results show that the existing process is positive in energy balance (-162 MJ/PE(COD) * a) and carbon footprint (-11.6 kg CO(2)-eq/PE(COD) * a) by supplying secondary products such as electricity from biogas production or mono-incineration and substituting fossil fuels in co-incineration. However, disposal routes for stabilized sludge differ considerably in their energy and greenhouse gas profiles. In total, LCA proves to be a suitable tool to support future investment decisions with information of environmental relevance on the impact of wastewater treatment, but also urban water systems in general.

Somatic coliphages as surrogates for enteroviruses in sludge hygienization treatments.

PubMed

Martín-Díaz, Julia; Casas-Mangas, Raquel; García-Aljaro, Cristina; Blanch, Anicet R; Lucena, Francisco

2016-01-01

Conventional bacterial indicators present serious drawbacks giving information about viral pathogens persistence during sludge hygienization treatments. This calls for the search of alternative viral indicators. Somatic coliphages' (SOMCPH) ability for acting as surrogates for enteroviruses was assessed in 47 sludge samples subjected to novel treatment processes. SOMCPH, infectious enteroviruses and genome copies of enteroviruses were monitored. Only one of these groups, the bacteriophages, was present in the sludge at concentrations that allowed the evaluation of treatment's performance. An indicator/pathogen relationship of 4 log10 (PFU/g dw) was found between SOMCPH and infective enteroviruses and their detection accuracy was assessed. The obtained results and the existence of rapid and standardized methods encourage the inclusion of SOMCPH quantification in future sludge directives. In addition, an existing real-time quantitative polymerase chain reaction (RT-qPCR) for enteroviruses was adapted and applied.

The demonstration of a novel sulfur cycle-based wastewater treatment process: sulfate reduction, autotrophic denitrification, and nitrification integrated (SANI®) biological nitrogen removal process.

PubMed

Lu, Hui; Wu, Di; Jiang, Feng; Ekama, George A; van Loosdrecht, Mark C M; Chen, Guang-Hao

2012-11-01

Saline water supply has been successfully practiced for toilet flushing in Hong Kong since 1950s, which saves 22% of freshwater in Hong Kong. In order to extend the benefits of saline water supply into saline sewage management, we have recently developed a novel biological organics and nitrogen removal process: the Sulfate reduction, Autotrophic denitrification, and Nitrification Integrated (SANI®) process. The key features of this novel process include elimination of oxygen demand in organic matter removal and production of minimal sludge. Following the success of a 500-day lab-scale trial, this study reports a pilot scale evaluation of this novel process treating 10 m(3) /day of 6-mm screened saline sewage in Hong Kong. The SANI® pilot plant consisted of a sulfate reduction up-flow sludge bed (SRUSB) reactor, an anoxic bioreactor for autotrophic denitrification and an aerobic bioreactor for nitrification. The plant was operated at a steady state for 225 days, during which the average removal efficiencies of both chemical oxygen demand (COD) and total suspended solids (TSS) at 87% and no excess sludge was purposefully withdrawn. Furthermore, a tracer test revealed 5% short circuit flow and a 34.6% dead zone in the SRUSB, indicating a good possibility to further optimize the treatment capacity of the process for full-scale application. Compared with conventional biological nitrogen removal processes, the SANI® process reduces 90% of waste sludge, which saves 35% of the energy and reduces 36% of fossil CO(2) emission. The SANI® process not only eliminates the major odor sources originating from primary treatment and subsequent sludge treatment and disposal during secondary saline sewage treatment, but also promotes saline water supply as an economic and sustainable solution for water scarcity and sewage treatment in water-scarce coastal areas. Copyright © 2012 Wiley Periodicals, Inc.

Sludge reduction in a small wastewater treatment plant by electro-kinetic disintegration.

PubMed

Chiavola, Agostina; Ridolfi, Alessandra; D'Amato, Emilio; Bongirolami, Simona; Cima, Ennio; Sirini, Piero; Gavasci, Renato

2015-01-01

Sludge reduction in a wastewater treatment plant (WWTP) has recently become a key issue for the managing companies, due to the increasing constraints on the disposal alternatives. Therefore, all the solutions proposed with the aim of minimizing sludge production are receiving increasing attention and are tested either at laboratory or full-scale to evaluate their real effectiveness. In the present paper, electro-kinetic disintegration has been applied at full-scale in the recycle loop of the sludge drawn from the secondary settlement tank of a small WWTP for domestic sewage. After the disintegration stage, the treated sludge was returned to the biological reactor. Three different percentages (50, 75 and 100%) of the return sludge flow rate were subjected to disintegration and the effects on the sludge production and the WWTP operation efficiency evaluated. The long-term observations showed that the electro-kinetic disintegration was able to drastically reduce the amount of biological sludge produced by the plant, without affecting its treatment efficiency. The highest reduction was achieved when 100% return sludge flow rate was subjected to the disintegration process. The reduced sludge production gave rise to a considerable net cost saving for the company which manages the plant.

Landfill leachate sludge use as soil additive prior and after electrocoagulation treatment: A cytological assessment using CHO-k1 cells.

PubMed

Morozesk, M; Bonomo, M M; Rocha, L D; Duarte, I D; Zanezi, E R L; Jesus, H C; Fernandes, M N; Matsumoto, S T

2016-09-01

Electrocoagulation has recently attracted attention as a potential technique for treating toxic effluents due to its versatility and environmental compatibility, generating a residue chemically suitable to be used as a soil additive. In the present study, landfill leachate sludge hazardous effects were investigated prior and after electrocoagulation process using in vitro assays with the mammalian cells CHO-k1. An integrated strategy for risk assessment was used to correctly estimate the possible adverse landfill leachate sludge effects on human health and ecosystem. Electrocoagulation process proved to be an effective treatment due to possibility to improve effluent adverse characteristics and produce sludge with potential to be used as soil additive. Despite low cytoxicity, the residue presented genotoxic and mutagenic effects, indicating a capacity to induce genetic damages, probably due to induction of polyploidization process in cells. The observed effects demand an improvement of waste management methods for reduce negative risks of landfill leachate sludge application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of the effects of temperature and sludge characteristics on odors and VOC emissions during the drying process of sewage sludge.

PubMed

Ding, Wenjie; Li, Lin; Liu, Junxin

2015-01-01

Sludge drying is a necessary step for sludge disposal. In this study, sludge was collected from two wastewater treatment plants, and dried at different temperatures in the laboratory. The emission of odor and total volatile organic compounds (TVOCs) during the sludge drying process were determined by an online odor monitoring system. The volatile organic compounds (VOCs) in off-gas were analyzed by gas chromatography-mass spectrometry. Results showed that sludge with 30% moisture content could be obtained in 51 minutes under drying temperature 100 °C but only within 27 minutes under 150 °C. Concentration of odor, TVOCs, sulfur-containing compounds (SCCs), and amines were changed with drying temperature and sludge sources. The maximum concentration of odor, TVOCs, SCCs, and amines were 503.13 ppm, 3.01 ppm, 8.15 ppm, and 11.27 ppm, respectively, at drying temperature 100 °C. These values reached 1,250.79, 8.10, 53.51, and 37.80 ppm when sludge dried at 150 °C. Odor concentration had a close relationship with emission of SCCs, amines, and TVOCs. The main VOCs released were benzene series and organic acid. Potential migration of substances in sludge was examined via analysis of off-gas and condensate, aiming to provide scientific data for effective sludge treatment and off-gas control.

Mesophilic and thermophilic activated sludge post-treatment of paper mill process water.

PubMed

Vogelaar, J C T; Bouwhuis, E; Klapwijk, A; Spanjers, H; van Lier, J B

2002-04-01

Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper mill using recycled wastepaper was studied. Two lab-scale plug flow activated sludge reactors were run in parallel for 6 months; a thermophilic reactor at 55 degrees C and a reference reactor at 30 degrees C. Both reactors were operated simultaneously at 20, 15 and 10 days SRT. The effects of temperature and SRT on sludge settleability and chemical oxygen demand (COD) removal efficiencies of different fractions were studied. Total COD removal percentages over the whole experimental period were 58+/-5% at 30 degrees C and 48 +/- 10% at 55 degrees C. The effect of the SRT on the total COD removal was negligible. Differences in total COD removal between both systems were due to a lesser removal of soluble and colloidal COD at 55 degrees C compared to the reference system. At 30 degrees C, colloidal COD removal percentages were 65+/-25%, 75+/-17% and 86+/-22% at 20, 15 and 10 days SRT, respectively. At 55 degrees C, these percentages were 48+/-34%, 40+/-28% and 70+/-25%, respectively. The effluent concentrations of colloidal COD in both systems were related to the influent concentration of colloidal material. The thermophilic sludge was not able to retain influent colloidal material as well as the mesophilic sludge causing a higher thermophilic effluent turbidity. Sludge settling properties were excellent in both reactor systems. These were neither temperature nor SRT dependent but were rather caused by extensive calcium precipitation in the aeration tanks creating a very dense sludge. For application in the board industry, a thermophilic in line treatment system seems feasible. The higher effluent turbidity is most likely offset by the energy gains of treatment under thermophilic conditions.

Lipid-enhancement of activated sludges obtained from conventional activated sludge and oxidation ditch processes.

PubMed

Revellame, Emmanuel D; Hernandez, Rafael; French, W Todd; Holmes, William E; Forks, Allison; Callahan, Robert

2013-11-01

Lipid-enhancement of activated sludges was conducted to increase the amount of saponifiable lipids in the sludges. The sludges were obtained from a conventional activated sludge (CAS) and an oxidation ditch process (ODP). Results showed 59-222% and 150-250% increase in saponifiable lipid content of the sludges from CAS and ODP, respectively. The fatty acid methyl ester (FAMEs) obtained from triacylglycerides was 57-67% (of total FAMEs) for enhanced CAS and 55-73% for enhanced ODP, a very significant improvement from 6% to 10% (CAS) and 4% to 8% (ODP). Regardless of the source, the enhancement resulted in sludges with similar fatty acid profile indicating homogenization of the lipids in the sludges. This study provides a potential strategy to utilize existing wastewater treatment facilities as source of significant amount of lipids for biofuel applications. Published by Elsevier Ltd.

Occurrence and risk assessment of nonylphenol and nonylphenol ethoxylates in sewage sludge from different conventional treatment processes.

PubMed

González, M M; Martín, J; Santos, J L; Aparicio, I; Alonso, E

2010-01-01

In the present work, the concentrations of the organic pollutants nonylphenol (NP) and nonylphenol mono- and diethoxylates (NP1EO and NP2EO, respectively) in primary, secondary, mixed, aerobically-digested, anaerobically-digested, dehydrated, compost and lagoon sludge samples from different sludge treatments have been evaluated. Toxicological risk assessment of these compounds in sludge and sludge-amended soil has also been reported. NP, NP1EO and NP2EO were monitored in sludge samples obtained from treatment plants located in Andalusia (south of Spain) based on anaerobic treatments (11 anaerobic-digestion wastewater treatment plants and 3 anaerobic wastewater stabilization ponds) or on aerobic treatments (3 aerobic-digestion wastewater treatment plants, 1 dehydration treatment plant and 2 composting plants). The sum of NP, NP1EO and NP2EO (NPE) concentrations has been evaluated in relation to the limit value of 50 mg/kg set by the European Union Sludge Directive draft published in April 2000 (Working Document on Sludge). In most of the samples, NP was present at higher concentration levels (mean value 88.0 mg/kg dm) than NP1EO (mean value 33.8 mg/kg dm) and NP2EO (mean value 14.0 mg/kg dm). The most contaminated samples were compost, anaerobically-digested sludge, lagoon sludge and aerobically-digested sludge samples, which contained NPE concentrations in the ranges 44-962 mg/kg dm, 8-669 mg/kg dm, 27-319 mg/kg dm and 61-282 mg/kg dm, respectively. Risk quotients, expressed as the ratios between environmental concentrations and the predicted no-effect concentrations, were higher than 1 for NP, NP1EO and NP2EO in the 99%, 92% and 36% of the studied samples, respectively; and higher than 1 in the 86%, 6% and 2%, respectively, after sludge application to soil, leading to a significant ecotoxicological risk mainly due to the presence of NP.

Activated Sludge.

ERIC Educational Resources Information Center

Saunders, F. Michael

1978-01-01

Presents the 1978 literature review of wastewater treatment. This review covers: (1) activated sludge process; (2) process control; (3) oxygen uptake and transfer; (4) phosphorus removal; (5) nitrification; (6) industrial wastewater; and (7) aerobic digestion. A list of 136 references is also presented. (HM)

Ultrasonic application to boost hydroxyl radical formation during Fenton oxidation and release organic matter from sludge

PubMed Central

Gong, Changxiu; Jiang, Jianguo; Li, De’an; Tian, Sicong

2015-01-01

We examined the effects of ultrasound and Fenton reagent on ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes for the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase soluble chemical oxygen demand (SCOD), total organic carbon (TOC), and extracellular polymeric substances (EPS) concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the release of SCOD by 2.1- and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the release of EPS by 1.2-fold compared with U alone. After U+F treatment, sludge showed a considerably finer particle size and looser microstructure based on fluorescence microscopy, and the concentration of hydroxyl radicals (OH•) increased from 0.26 mM by F treatment to 0.43 mM by U+F treatment based on fluorescence spectrophotometer. This demonstrated that U+F treatment improves the release of organic matter from sludge. PMID:26066562

Enhancing dewaterability of waste activated sludge by combined oxidative conditioning process with zero-valent iron and peroxymonosulfate.

PubMed

Zhou, Xu; Jin, Wenbiao; Chen, Hongyi; Chen, Chuan; Han, Songfang; Tu, Renjie; Wei, Wei; Gao, Shu-Hong; Xie, Guo-Jun; Wang, Qilin

2017-11-01

The enhancement of sludge dewaterability is of great importance for facilitating the sludge disposal during the operation of wastewater treatment plants. In this study, a novel oxidative conditioning approach was applied to enhance the dewaterability of waste activated sludge by the combination of zero-valent iron (ZVI) and peroxymonosulfate (PMS). It was found that the dewaterability of sludge was significantly improved after the addition of ZVI (0-4 g/g TSS) (TSS: total suspended solids) and PMS (0-1 g/g TSS). The optimal addition amount of ZVI and PMS was 0.25 g/g TSS and 0.1 g/g TSS, respectively, under which the capillary suction time of the sludge was reduced by approximately 50%. The decomposition of sludge flocs could contribute to the improved sludge dewaterability. Economic analysis demonstrated that the proposed conditioning process with ZVI and PMS was more economical than the ZVI + peroxydisulfate and the traditional Fenton conditioning processes.

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments

PubMed Central

Ouardani, Imen; Turki, Syrine; Aouni, Mahjoub

2016-01-01

ABSTRACT Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem. Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated. Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 103 genome copies [GC]/ml) and influents (2.7 × 103 GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did. Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater. IMPORTANCE This report provides important data on the incidence, behavior, seasonality, and genotype distribution of HAV in the environment in Tunisia, as well as the risk of infection derived from its occurrence in effluents due to inadequate wastewater treatment. In addition, these findings seem to confirm that the prevalence of HAV depends on socioeconomic level, sanitary conditions in the communities, sewage facilities, the locality, and the climate. The wide dispersion of HAV in effluents proves the inefficacity of the current wastewater treatment processes used in Tunisia to remove virus; therefore, establishment of tertiary treatment processes or replacement of the medium-charge activated sludge (conventional activated sludge) by the low-charge version (oxidation ditch activated sludge) is absolutely needed. Rapid detection of the HAV genome in wastewater may provide a timely warning sign to health authorities to implement population protection measures. PMID:27107113

A novel approach to realize SANI process in freshwater sewage treatment--Use of wet flue gas desulfurization waste streams as sulfur source.

PubMed

Jiang, Feng; Zhang, Liang; Peng, Guo-Liang; Liang, Si-Yun; Qian, Jin; Wei, Li; Chen, Guang-Hao

2013-10-01

SANI (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated) process has been approved to be a sludge-minimized sewage treatment process in warm and coastal cities with seawater supply. In order to apply this sulfur-based process in inland cold areas, wet flue gas desulfurization (FGD) can be simplified and integrated with SANI process, to provide sulfite as electron carrier for sulfur cycle in sewage treatment. In this study, a lab-scale system of the proposed novel process was developed and run for over 200 days while temperature varied between 30 and 5 °C, fed with synthetic FGD wastewaters and sewage. The sulfite-reducing upflow anaerobic sludge bed (SrUASB) reactor, as the major bioreactor of the system, removed 86.9% of organics while the whole system removed 94% of organics even when water temperature decreased to around 10 °C. The bactericidal effect of sulfite was not observed in the SrUASB reactor, while thiosulfate was found accumulated under psychrophilic conditions. The sludge yield of the SrUASB reactor was determined to be 0.095 kg VSS/kg COD, higher than of sulfate reduction process but still much lower than of conventional activated sludge processes. The dominant microbes in the SrUASB reactor were determined as Lactococcus spp. rather than sulfate-reducing bacteria, but sulfite reduction still contributed 85.5% to the organic carbon mineralization in this reactor. Ammonia and nitrate were effectively removed in the aerobic and anoxic filters, respectively. This study confirms the proposed process was promising to achieve sludge-minimized sewage treatment integrating with flue gas desulfurization in inland and cold areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Effects of ultrasonic pretreatment on drying characteristics of sewage sludge].

PubMed

Li, Run-Dong; Yang, Yu-Ting; Li, Yan-Long; Niu, Hui-Chang; Wei, Li-Hong; Sun, Yang; Ke, Xin

2009-11-01

The high water content of sewage sludge has engendered many inconveniences to its treatment and disposal. While ultrasonic takes on unique advantages on the sludge drying because of its high ultrasonic power, mighty penetrating capability and the ability of causing cavitations. Thus this research studies the characteristics influences of ultrasonic bring to the sludge drying and effects of the exposure time, ultrasonic generator power, temperatures of ultrasonic and drying temperature on the drying characteristics of dewatered sludge. Results indicate that ultrasonic pretreatment could speed up evaporation of the free water in sludge surface and help to end the drying stage with constant speed. In addition, ultrasonic treatment can effectively improve the sludge drying efficiency which could be more evident with the rise of the ultrasonic power (100-250 W), ultrasonic temperature and drying temperature. If dried under low temperature such as 105 degrees C, sludge will have premium drying characteristics when radiated under ultrasound for a shorter time such as 3 min. In the end, the ultrasonic treatment is expected to be an effective way to the low-cost sludge drying and also be an important reference to the optimization of the sludge drying process because of its effects on the increase of sludge drying efficiency.

Reducing capacities and redox potentials of humic substances extracted from sewage sludge.

PubMed

Yang, Zhen; Du, Mengchan; Jiang, Jie

2016-02-01

Humic substances (HS) are redox active organic materials that can be extracted from sewage sludge generated in wastewater treatment processes. Due to the poor understanding of reducing capacity, redox potentials and redox active functional groups of HS in sewage sludge, the potential contribution of sludge HS in transformation of wastewater contaminants is unclear. In the present study, the number of electrons donated or accepted by sewage sludge HS were quantified before and after reduction by iron compounds that possess different redox potentials and defined as the reducing capacity of the sewage sludge. In contrast to previous studies of soil and commercial humic acids (HA), reduced sludge HA showed a lower reducing capacity than that of native HA, which implies formation of semiquinone radicals since the semiquinone radical/hydroquinone pair has a much higher redox potential than the quinone/hydroquinone pair. It is novel that reducing capacities of sludge HA were determined in the redox potential range from -314 to 430 mV. The formation of semiquinone radicals formed during the reduction of quinone moieties in sludge HA is shown by three-dimensional excitation/emission matrix fluorescence spectroscopies information, increasing fluorescence intensities and blue-shifting of the excitation/emission peak of reduced sludge HA. Knowledge of sludge HS redox potentials and corresponding reducing capacities makes it possible to predict the transformation of redox active pollutants and facilitate manipulation and optimization of sludge loading wastewater treatment processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of municipal sludge and grease co-digestion using disintegration technologies.

PubMed

Bouchy, L; Pérez, A; Camacho, P; Rubio, P; Silvestre, G; Fernández, B; Cano, R; Polanco, M; Díaz, N

2012-01-01

Many drivers tend to foster the development of renewable energy production in wastewater treatment plants as many expectations rely upon energy recovery from sewage sludge, for example through biogas use. This paper is focused on the assessment of grease waste (GW) as an adequate substrate for co-digestion with municipal sludge, as it has a methane potential of 479-710 LCH(4)/kg VS, as well as the evaluation of disintegration technologies as a method to optimize the co-digestion process. With this objective three different pre-treatments have been selected for evaluation: thermal hydrolysis, ultrasound and enzymatic treatment. Results have shown that co-digestion processes without pre-treatment had a maximum increment of 128% of the volumetric methane productivity when GW addition was 23% inlet (at 20 days of HRT and with an OLR of 3.0 kg COD/m(3)d), compared with conventional digestion of sewage sludge alone. Concerning the application of the selected disintegration technologies, all pre-treatments showed improvements in terms of methane yield (51.8, 89.5 and 57.6% more for thermal hydrolysis, ultrasound and enzymatic treatment, respectively, compared with non-pretreated wastes), thermal hydrolysis of GW and secondary sludge being the best configuration as it improved the solubilization of the organic matter and the hydrodynamic characteristics of digestates.

Removal of endocrine-disrupting chemicals and conventional pollutants in a continuous-operating activated sludge process integrated with ozonation for excess sludge reduction.

PubMed

Nie, Yafeng; Qiang, Zhimin; Ben, Weiwei; Liu, Junxin

2014-06-01

Sludge ozonation is considered as a promising technology to achieve a complete reduction of excess sludge, but as yet its effects on the removal of endocrine-disrupting chemicals (EDCs) and conventional pollutants (i.e., COD, N and P) in the activated sludge process are still unclear. In this study, two lab-scale continuous-operating activated sludge treatment systems were established: one was operated in conjunction with ozonation for excess sludge reduction, and the other was operated under normal conditions as control. The results indicate that an ozone dose of 100 mg O₃ g(-1)SS led to a zero yield of excess sludge in the sludge-reduction system during a continuous-operating period of 45d. Although ozonation gave a relatively lower specific oxygen uptake rate of activated sludge, it had little effect on the system's removal performance of COD and nitrogen substances. As a plus, sludge ozonation contributed a little more removal of target EDCs (estrone, 17β-estrodiol, estriol, 17α-ethinylestradiol, bisphenol A, and 4-nonylphenol). However, the total phosphorus removal declined notably due to its accumulation in the sludge-reduction system, which necessitates phosphorus recovery for the activated sludge process. Copyright © 2014 Elsevier Ltd. All rights reserved.

New technology for recyclingmaterials from oily cold rollingmill sludge

NASA Astrophysics Data System (ADS)

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Meng, Ling; Liu, Yang

2013-12-01

Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of "hydrometallurgical treatment + hydrothermal synthesis" was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.

Operation of an aquatic worm reactor suitable for sludge reduction at large scale.

PubMed

Hendrickx, Tim L G; Elissen, Hellen H J; Temmink, Hardy; Buisman, Cees J N

2011-10-15

Treatment of domestic waste water results in the production of waste sludge, which requires costly further processing. A biological method to reduce the amount of waste sludge and its volume is treatment in an aquatic worm reactor. The potential of such a worm reactor with the oligochaete Lumbriculus variegatus has been shown at small scale. For scaling up purposes, a new configuration of the reactor was designed, in which the worms were positioned horizontally in the carrier material. This was tested in a continuous experiment of 8 weeks where it treated all the waste sludge from a lab-scale activated sludge process. The results showed a higher worm growth rate compared to previous experiments with the old configuration, whilst nutrient release was similar. The new configuration has a low footprint and allows for easy aeration and faeces collection, thereby making it suitable for full scale application. Copyright © 2011 Elsevier Ltd. All rights reserved.

Lignor process for acidic rock drainage treatment.

PubMed

Zhuang, J M; Walsh, T

2004-09-01

The process using lignosulfonates for acidic rock drainage (ARD) treatment is referred to as the Lignor process. Lignosulfonates are waste by-products produced in the sulfite pulping process. The present study has shown lignosulfonates are able to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the dotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long-term stability of the sludge against leaching. The Lignor process involves metal sorption with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 - 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The Lignor process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the B.C. Regulations. Compared with the high-density sludge (HDS) process, the Lignor process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability.

Effect of various types of thermochemical processing of sewage sludges on phosphorus speciation, solubility, and fertilization performance.

PubMed

Steckenmesser, Daniel; Vogel, Christian; Adam, Christian; Steffens, Diedrich

2017-04-01

Sewage sludge has one of the highest phosphorus (P) recovery potentials of all waste materials. Therefore, P-recycling from sewage sludge could contribute to closing the P-cycle. Recently, various thermal processes for P-recovery have been developed, but there is still a demand for information on the effect of different process parameters (e.g. additives and temperature) on P-speciation and especially on the fertilization performance. In the present study, two common methods (low-temperature conversion at 400-500°C and thermochemical treatment at 950°C) were investigated and combined to produce highly bioavailable P-fertilizers from two different types of sewage sludge based on chemical phosphorus precipitation (Chem-P) and enhanced biological phosphorus removal (Bio-P). The results of P-fractionation, X-ray diffraction analysis, and pot experiments with maize showed that Bio-P sludges attain high P-plant-availability after treatment at low temperatures (400°C). In contrast, Chem-P sludges can adequately be treated at higher temperatures under reductive conditions with sodium additives to form highly bioavailable calcium-sodium-phosphate. Additionally, also highly heavy-metal contaminated sludges can be thermochemically treated at high temperatures to achieve the legal requirements for fertilizers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heavy metals and its chemical speciation in sewage sludge at different stages of processing.

PubMed

Tytła, Malwina; Widziewicz, Kamila; Zielewicz, Ewa

2016-01-01

The analysis of heavy metal concentrations and forms in sewage sludge constitutes an important issue in terms of both health and environmental hazards the metals pose. The total heavy metals concentration enables only the assessment of its contamination. Hence the knowledge of chemical forms is required to determine their environmental mobility and sludge final disposal. Heavy metals speciation was studied by using four-stage sequential extraction BCR (Community Bureau of Reference). This study was aimed at determining the total concentration of selected heavy metals (Zn, Cu, Ni, Pb, Cd, Cr and Hg) and their chemical forms (except for Hg) in sludge collected at different stages of its processing at two municipal Wastewater Treatment Plants in southern Poland. Metals contents in sludge samples were determined by using flame atomic absorption spectrometry (FAAS) and electrothermal atomic absorption spectrometry (ETAAS). This study shows that Zn and Cu appeared to be the most abundant in sludge, while Cd and Hg were in the lowest concentrations. The sewage sludge revealed the domination of immobile fractions over the mobile ones. The oxidizable and residual forms were dominant for all the heavy metals. There was also a significant difference in metals speciation between sludges of different origin which was probably due to differences in wastewater composition and processes occurring in biological stage of wastewater treatment. The results indicate a negligible capability of metals to migrate from sludge into the environment. Our research revealed a significant impact of thickening, stabilization and hygienization on the distribution of heavy metals in sludge and their mobility.

Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cristale, Joyce; Ramos, Dayana D.; Dantas, Renato F.

2016-01-15

This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L{sup −1} to 150 µg L{sup −1}. During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g{sup −1} dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatmentmore » and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H{sub 2}O{sub 2} and O{sub 3}) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H{sub 2}O{sub 2} and O{sub 3}. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs. - Highlights: • OPFRs were detected in wastewater and sludge of all studied WWTPs. • Alkyl and chloroalkyl phosphates were present in secondary treatment effluents. • TBOEP, TNBP and TIBP were degraded by UV/H{sub 2}O{sub 2} and O{sub 3} treatment. • TCEP, TCIPP and TDCPP were resistant to both secondary and tertiary treatment.« less

Fate of cyanobacteria and their metabolites during water treatment sludge management processes.

PubMed

Ho, Lionel; Dreyfus, Jennifer; Boyer, Justine; Lowe, Todd; Bustamante, Heriberto; Duker, Phil; Meli, Tass; Newcombe, Gayle

2012-05-01

Cyanobacteria and their metabolites are an issue for water authorities; however, little is known as to the fate of coagulated cyanobacterial-laden sludge during waste management processes in water treatment plants (WTPs). This paper provides information on the cell integrity of Anabaena circinalis and Cylindrospermopsis raciborskii during: laboratory-scale coagulation/sedimentation processes; direct filtration and backwashing procedures; and cyanobacterial-laden sludge management practices. In addition, the metabolites produced by A. circinalis (geosmin and saxitoxins) and C. raciborskii (cylindrospermopsin) were investigated with respect to their release (and possible degradation) during each of the studied processes. Where sedimentation was used, coagulation effectively removed cyanobacteria (and intracellular metabolites) without any considerable exertion on coagulant demand. During direct filtration experiments, cyanobacteria released intracellular metabolites through a stagnation period, suggesting that more frequent backwashing of filters may be required to prevent floc build-up and metabolite release. Cyanobacteria appeared to be protected within the flocs, with minimal damage during backwashing of the filters. Within coagulant sludge, cyanobacteria released intracellular metabolites into the supernatant after 3d, even though cells remained viable up to 7d. This work has improved the understanding of cyanobacterial metabolite risks associated with management of backwash water and sludge and is likely to facilitate improvements at WTPs, including increased monitoring and the application of treatment strategies and operational practices, with respect to cyanobacterial-laden sludge and/or supernatant recycle management. Copyright © 2012 Elsevier B.V. All rights reserved.

Qualitative and Quantitative Assessment of Sewage Sludge by Gamma Irradiation with Pasteurization as a Tool for Hygienization

NASA Astrophysics Data System (ADS)

Priyadarshini, J.; Roy, P. K.; Mazumdar, A.

2014-01-01

In this research work, management of sewage sludge disposal on agricultural soils is addressed. The increasing amount of sewage sludge and more legislative regulation of its disposal have stimulated the need for developing new technologies to recycle sewage sludge efficiently. The research was structured along two main avenues, namely, the efficacy of the irradiation process for removing enteric pathogenic microorganisms and the potential of irradiated sludge as a soil amendment. This study investigated how application of irradiation with heat treatment reduced pathogens in sewage sludge. Raw and pasteurised Sewage sludge was treated at different dose treatment of 1.5, 3 and 5 kilogray (kGy) gamma irradiation individually and for 3 kGy sufficiency was achieved. Decrease in irradiation dose from 5 to 3 kGy was observed for pasteurised sludge resulting in saving of radiation energy. The presence of heavy metals in untreated sewage sludge has raised concerns, which decreases after irradiation.

Recent development in the treatment of oily sludge from petroleum industry: a review.

PubMed

Hu, Guangji; Li, Jianbing; Zeng, Guangming

2013-10-15

Oily sludge is one of the most significant solid wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. In this review, the origin, characteristics, and environmental impacts of oily sludge were introduced. Many methods have been investigated for dealing with PHCs in oily sludge either through oil recovery or sludge disposal, but little attention has been paid to handle its various heavy metals. These methods were discussed by dividing them into oil recovery and sludge disposal approaches. It was recognized that no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Future efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The comprehensive examination of oily sludge treatment methods will help researchers and practitioners to have a good understanding of both recent developments and future research directions. Copyright © 2013 Elsevier B.V. All rights reserved.

SITE DEMONSTRATION OF THE BASIC EXTRACTIVE SLUDGE TREATMENT PROCESS

EPA Science Inventory

The Superfund Innovative Technology Evaluation (SITE) Program, in cooperation with EPA Region 5, the Great Lakes National Program Office (GLNPO), and the U.S. Army Corps of Engineers (COE) planned and executed a pilot-scla e evaluation of the Basic Extyractive Sludge Treatment (B...

Carbon, nitrogen and phosphorus removal mechanisms of aerobic granules.

PubMed

Sarma, Saurabh Jyoti; Tay, Joo-Hwa

2018-04-10

Aerobic granules are the potential tools to develop modern wastewater treatment technologies with improved nutrient removal efficiency. These granules have several promising advantages over conventional activated sludge-based wastewater treatment processes. This technology has the potential of reducing the infrastructure and operation costs of wastewater treatment by 25%, energy requirement by 30%, and space requirement by 75%. The nutrient removal mechanisms of aerobic granules are slightly different from that of the activated sludge. For instance, unlike activated sludge process, according to some reports, as high as 70% of the total phosphorus removed by aerobic granules were attributed to precipitation within the granules. Similarly, aerobic granule-based technology reduces the total amount of sludge produced during wastewater treatment. However, the reason behind this observation is unknown and it needs further explanations based on carbon and nitrogen removal mechanisms. Thus, as a part of the present review, a set of new hypotheses have been proposed to explain the peculiar nutrient removal mechanisms of the aerobic granules.

Systematic comparison of mechanical and thermal sludge disintegration technologies.

PubMed

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. Copyright 2009 Elsevier Ltd. All rights reserved.

An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling.

PubMed

Yuan, Jiajia; Dong, Wenyi; Sun, Feiyun; Li, Pu; Zhao, Ke

2016-05-01

An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.

[Treatment of carbonization effluent by the ultrasonic radiation and activated sludge process].

PubMed

Ning, Ping; Xu, Jinqiu; Huang, Dongbin; Ma, Xiaoli; Xu, Xiaojun; Li, Ziyan

2003-05-01

The paper deals with the degradation of organic pollutants by the ultrasonic irradiation-activated sludge process. The treatment of the real coking wastewater of Kunming coke making-gas plant was studied with the water quality model. Using the ultrasonic irradiation-activated sludge process the organic pollutants in the real coking wastewater can be degraded effectively. The influence factors of the ultrasonic degradation effect such as initial concentration, aerated gas and ultrasonic density were investigated and mechanism was explored. The result shows that the ultrasonic degradation effect was high with the decrease of initial concentration of the CODCr, the presence of aerated gas and the increase of ultrasonic density. At the initial CODCr concentration of 807 mg/L, when air acted as aerated gas and only air itself (no ultrasound) was exerted on the wastewater, the degradation rate of the CODCr will be 4.5%. However, when the ultrasound of the intensity of 119.4 kW/m2 was exerted on the wastewater, the degradation rate of the CODCr will be 65%. Compared with the activated sludge process alone, the combination of the ultrasonic irradiation and activated sludge process can increase the degradation rate of the CODCr from 45% to 81%. The oxygen consumption rate of the carbonization effluent obviously decreased in the presence of the activated sludge. This shows the carbonization effluent is not biotoxic behind the ultrasonic irradiation.

Production of biodegradable plastics from activated sludge generated from a food processing industrial wastewater treatment plant.

PubMed

Suresh Kumar, M; Mudliar, S N; Reddy, K M K; Chakrabarti, T

2004-12-01

Most of the excess sludge from a wastewater treatment plant (60%) is disposed by landfill. As a resource utilization of excess sludge, the production of biodegradable plastics using the sludge has been proposed. Storage polymers in bacterial cells can be extracted and used as biodegradable plastics. However, widespread applications have been limited by high production cost. In the present study, activated sludge bacteria in a conventional wastewater treatment system were induced, by controlling the carbon: nitrogen ratio to accumulate storage polymers. Polymer yield increased to a maximum 33% of biomass (w/w) when the C/N ratio was increased from 24 to 144, where as specific growth yield decreased with increasing C/N ratio. The conditions which are required for the maximum polymer accumulation were optimized and are discussed.

Impact of sludge treatments on the extractability and fate of acetyl sulfamethoxazole residues in amended soils.

PubMed

Geng, Chunnu; Bergheaud, Valérie; Garnier, Patricia; Zhu, Yong-Guan; Haudin, Claire-Sophie

2018-03-01

Sludge recycled in agriculture may bring antibiotics into cropped soils. The nature, total amount, and availability of the antibiotics in soil partly depend on the sludge treatments. Our paper compares the fate of N-acetyl sulfamethoxazole (AC-SMX) residues between soils incubated with the same sludge but submitted to different processes before being added in soil. The fate of 14 C-AC-SMX residues was studied in mixtures of soil and sludges at different treatment levels: 1) activated and 2) centrifuged sludges, both enriched with 14 C-AC-SMX, and 3) limed and 4) heat-dried sludges obtained by treating the previously contaminated centrifuged sludge. The evolution of the extractability of 14 C residues (CaCl 2 , methanol) and their mineralization were followed during 119 days. More than 80% of the initial 14 C-activity was no longer extractable after 14 days, except in soil with limed sludge. Liming and drying the centrifuged sludge decreased the mineralized 14 C fraction from 5.7-6.4% to 1.2-1.8% and consequently, the corresponding soils contained more 14 C residues after 119 days. Although 14 C residues were more CaCl 2 -extractable in soil with limed sludge, they seemed to be poorly bioavailable for biodegradation. For all solid sludges, the mineralization rate of 14 C-AC-SMX residues was strongly correlated to that of sludge organic carbon, with a coefficient three times lower for the limed and dried sludges than for the centrifuged sludge after 14 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Low-temperature thermal pre-treatment of municipal wastewater sludge: Process optimization and effects on solubilization and anaerobic degradation.

PubMed

Nazari, Laleh; Yuan, Zhongshun; Santoro, Domenico; Sarathy, Siva; Ho, Dang; Batstone, Damien; Xu, Chunbao Charles; Ray, Madhumita B

2017-04-15

The present study examines the relationship between the degree of solubilization and biodegradability of wastewater sludge in anaerobic digestion as a result of low-temperature thermal pre-treatment. The main effect of thermal pre-treatment is the disintegration of cell membranes and thus solubilization of organic compounds. There is an established correlation between chemical oxygen demand (COD) solubilization and temperature of thermal pre-treatment, but results of thermal pre-treatment in terms of biodegradability are not well understood. Aiming to determine the impact of low temperature treatments on biogas production, the thermal pre-treatment process was first optimized based on an experimental design study on waste activated sludge in batch mode. The optimum temperature, reaction time and pH of the process were determined to be 80 °C, 5 h and pH 10, respectively. All three factors had a strong individual effect (p < 0.001), with a significant interaction effect for temp. pH 2 (p = 0.002). Thermal pre-treatments, carried out on seven different municipal wastewater sludges at the above optimum operating conditions, produced increased COD solubilization of 18.3 ± 7.5% and VSS reduction of 27.7 ± 12.3% compared to the untreated sludges. The solubilization of proteins was significantly higher than carbohydrates. Methane produced in biochemical methane potential (BMP) tests, indicated initial higher rates (p = 0.0013) for the thermally treated samples (k hyd up to 5 times higher), although the ultimate methane yields were not significantly affected by the treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Human enteric viruses in a wastewater treatment plant: evaluation of activated sludge combined with UV disinfection process reveals different removal performances for viruses with different features.

PubMed

Lizasoain, A; Tort, L F L; García, M; Gillman, L; Alberti, A; Leite, J P G; Miagostovich, M P; Pou, S A; Cagiao, A; Razsap, A; Huertas, J; Berois, M; Victoria, M; Colina, R

2018-03-01

This study assess the quality of wastewater through the detection and quantification of important viruses causing gastroenteritis at different stages of the wastewater treatment process in an activated-sludge wastewater treatment plant with ultraviolet disinfection. Ten sampling events were carried out in a campaign along a period of 18 months collecting wastewater samples from the influent, after the activated-sludge treatment, and after the final disinfection with UV radiation. Samples were concentrated through ultracentrifugation and analysed using retro-transcription, PCR and real time quantitative PCR protocols, for detection and quantification of Group A Rotavirus (RVA), Human Astrovirus (HAstV), Norovirus Genogroup II (NoV GII) and Human Adenovirus (HAdV). HAdV (100%), NoV GII (90%), RVA (70%) and HAstV (60%) were detected in influent samples with concentration from 1·4 (NoV GII) to 8·0 (RVA) log 10  gc l -1 . Activated-sludge treatment reached well quality effluents with low organic material concentration, although nonstatistical significant differences were registered among influent and postactivated sludge treatment samples, regarding the presence and concentration for most viruses. All post-UV samples were negative for NoV GII and HAstV, although RVA and HAdV were detected in 38% and 63% of those samples respectively, with concentration ranging from 2·2 to 5·5 and 3·1 to 3·4 log 10  gc l -1 . This study demonstrates that an activated-sludge wastewater treatment plant with UV disinfection reduces to levels below the detection limit those single-stranded RNA viruses as noroviruses and astroviruses and reach significant lower levels of rotaviruses and adenoviruses after the complete treatment process. © 2017 The Society for Applied Microbiology.

Cost-effective solutions for sewage treatment in developing countries--the case of Brazil.

PubMed

Jordão, E P; Volschan, I

2004-01-01

Cost-effective solutions are a must in developing countries, not only regarding investment costs, but also in respect to technology and operating practices. With these two goals in mind, in Brazil a particular effort has been directed for the development and application of the Chemical Enhanced Primary Treatment (CEPT) process and of the Upflow Anaerobic Sludge Blanket (UASB) process, both followed by complementary secondary treatment. Both technologies are under current expansion in Brazil. Large CEPT plants have been designed and built, up to 3.7 m3/s average design flow, as well as large UASB reactors, up to 3.0 m3/s average design flow. The applied technologies are cost-effective: they present low investment and efficiencies of BOD removal of up to 50% to 70%. They allow the plant construction in steps, an initial phase with efficiency over the usual primary treatment, and in order to achieve best effluent quality and meet legal water quality standards, a logic upgrade post-treatment can later on be implemented. The higher initial reduction of BOD and TSS also permits savings in construction and operational costs of secondary treatment, due to lower organic load and lower energy consumption. Sludge represents a particular point of attention: in the cases when the CEPT was used, Chemical Stabilisation of the Sludge (CSS) has also been practiced, eliminating the high construction costs of the digesters, all the plant staying chemically operated. In the cases when the UASB is used preceding secondary treatment, sludge can easily return to the anaerobic vessel, the costly sludge digestion unit being avoided. UASB reactors have practically no equipment in the anaerobic vessel, no energy consumption, low sludge production, and when applied in hot climates as in Brazil, heating devices are not required. The Brazilian experience, some particular cases, special comments on design and different secondary treatment processes are presented in this paper, as a contribution to the discussion of cost and benefits, a prime point to be considered.

Cost minimization in a full-scale conventional wastewater treatment plant: associated costs of biological energy consumption versus sludge production.

PubMed

Sid, S; Volant, A; Lesage, G; Heran, M

2017-11-01

Energy consumption and sludge production minimization represent rising challenges for wastewater treatment plants (WWTPs). The goal of this study is to investigate how energy is consumed throughout the whole plant and how operating conditions affect this energy demand. A WWTP based on the activated sludge process was selected as a case study. Simulations were performed using a pre-compiled model implemented in GPS-X simulation software. Model validation was carried out by comparing experimental and modeling data of the dynamic behavior of the mixed liquor suspended solids (MLSS) concentration and nitrogen compounds concentration, energy consumption for aeration, mixing and sludge treatment and annual sludge production over a three year exercise. In this plant, the energy required for bioreactor aeration was calculated at approximately 44% of the total energy demand. A cost optimization strategy was applied by varying the MLSS concentrations (from 1 to 8 gTSS/L) while recording energy consumption, sludge production and effluent quality. An increase of MLSS led to an increase of the oxygen requirement for biomass aeration, but it also reduced total sludge production. Results permit identification of a key MLSS concentration allowing identification of the best compromise between levels of treatment required, biological energy demand and sludge production while minimizing the overall costs.

A simple empirical model for the clarification-thickening process in wastewater treatment plants.

PubMed

Zhang, Y K; Wang, H C; Qi, L; Liu, G H; He, Z J; Fan, H T

2015-01-01

In wastewater treatment plants (WWTPs), activated sludge is thickened in secondary settling tanks and recycled into the biological reactor to maintain enough biomass for wastewater treatment. Accurately estimating the activated sludge concentration in the lower portion of the secondary clarifiers is of great importance for evaluating and controlling the sludge recycled ratio, ensuring smooth and efficient operation of the WWTP. By dividing the overall activated sludge-thickening curve into a hindered zone and a compression zone, an empirical model describing activated sludge thickening in the compression zone was obtained by empirical regression. This empirical model was developed through experiments conducted using sludge from five WWTPs, and validated by the measured data from a sixth WWTP, which fit the model well (R² = 0.98, p < 0.001). The model requires application of only one parameter, the sludge volume index (SVI), which is readily incorporated into routine analysis. By combining this model with the conservation of mass equation, an empirical model for compression settling was also developed. Finally, the effects of denitrification and addition of a polymer were also analysed because of their effect on sludge thickening, which can be useful for WWTP operation, e.g., improving wastewater treatment or the proper use of the polymer.

Treatment and disposal of refinery sludges: Indian scenario.

PubMed

Bhattacharyya, J K; Shekdar, A V

2003-06-01

Crude oil is a major source of energy and feedstock for petrochemicals. Oily sludge, bio-sludge and chemical sludge are the major sludges generated from the processes and effluent treatment plants of the refineries engaged in crude oil refining operations. Refineries in India generate about 28,220 tons of sludge per annum. Various types of pollutants like phenols, heavy metals, etc. are present in the sludges and they are treated as hazardous waste. Oily sludge, which is generated in much higher amount compared to other sludges, contains phenol (90-100 mg/kg), nickel (17-25 mg/kg), chromium (27-80 mg/kg), zinc (7-80 mg/kg), manganese (19-24 mg/kg), cadmium (0.8-2 mg/kg), copper (32-120 mg/kg) and lead (0.001-0.12 mg/ kg). Uncontrolled disposal practices of sludges in India cause degradation of environmental and depreciation of aesthetic quality. Environmental impact due to improper sludge management has also been identified. Salient features of various treatment and disposal practices have been discussed. Findings of a case study undertaken by the authors for Numaligarh Refinery in India have been presented. Various system alternatives have been identified for waste management in Numaligarh Refinery. A ranking exercise has been carried out to evaluate the alternatives and select the appropriate one. A detailed design of the selected waste management system has been presented.

JPL Activated Carbon Treatment System (ACTS) for sewage

NASA Technical Reports Server (NTRS)

1976-01-01

An Activated Carbon Treatment System (ACTS) was developed for sewage treatment and is being applied to a one-million gallon per day sewage treatment pilot plant in Orange County California. Activities reported include pyrolysis and activation of carbon-sewage sludge, and activated carbon treatment of sewage to meet ocean discharge standards. The ACTS Sewage treatment operations include carbon-sewage treatment, primary and secondary clarifiers, gravity (multi-media) filter, filter press dewatering, flash drying of carbon-sewage filter cake, and sludge pyrolysis and activation. Tests were conducted on a laboratory scale, 10,000 gallon per day demonstration plant and pilot test equipment. Preliminary economic studies are favorable to the ACTS process relative to activated sludge treatment for a 175,000,000 gallon per day sewage treatment plant.

Behavior of radioactive materials and safety stock of contaminated sludge.

PubMed

Tsushima, Ikuo

2017-01-28

The radioactive fallout from the Fukushima Dai-ichi nuclear power plant disaster in 2011 has flowed into and accumulated in many wastewater treatment plants (WWTPs) via sewer systems; this has had a negative impact on WWTPs in eastern Japan. The behavior of radioactive materials was analyzed at four WWTPs in the Tohoku and Kanto regions to elucidate the mechanism by which radioactive materials are concentrated during the sludge treatment process from July 2011 to March 2013. Furthermore, numerical simulations were conducted to study the safe handling of contaminated sewage sludge stocked temporally in WWTPs. Finally, a dissolution test was conducted by using contaminated incinerated ash and melted slag derived from sewage sludge to better understand the disposal of contaminated sewage sludge in landfills. Measurements indicate that a large amount of radioactive material accumulates in aeration tanks and is becoming trapped in the concentrated sludge during the sludge condensation process. The numerical simulation indicates that a worker's exposure around contaminated sludge is less than 1 µSv/h when maintaining an isolation distance of more than 10 m, or when shielding with more than 20-cm-thick concrete. The radioactivity level of the eluate was undetectable in 9 out of 12 samples; in the remaining three samples, the dissolution rates were 0.5-2.7%.

Oil recovery from refinery oily sludge via ultrasound and freeze/thaw.

PubMed

Zhang, Ju; Li, Jianbing; Thring, Ronald W; Hu, Xuan; Song, Xinyuan

2012-02-15

The effective disposal of oily sludge generated from the petroleum industry has received increasing concerns, and oil recovery from such waste was considered as one feasible option. In this study, three different approaches for oil recovery were investigated, including ultrasonic treatment alone, freeze/thaw alone and combined ultrasonic and freeze/thaw treatment. The results revealed that the combined process could achieve satisfactory performance by considering the oil recovery rate and the total petroleum hydrocarbon (TPH) concentrations in the recovered oil and wastewater. The individual impacts of five different factors on the combined process were further examined, including ultrasonic power, ultrasonic treatment duration, sludge/water ratio in the slurry, as well as bio-surfactant (rhamnolipids) and salt (NaCl) concentrations. An oil recovery rate of up to 80.0% was observed with an ultrasonic power of 66 W and an ultrasonic treatment duration of 10 min when the sludge/water ratio was 1:2 without the addition of bio-surfactant and salt. The examination of individual factors revealed that the addition of low concentration of rhamnolipids (<100mg/L) and salt (<1%) to the sludge could help improve the oil recovery from the combined treatment process. The experimental results also indicated that ultrasound and freeze/thaw could promote the efficiency of each other, and the main mechanism of oil recovery enhancement using ultrasound was through enhanced desorption of petroleum hydrocarbons (PHCs) from solid particles. Copyright © 2011 Elsevier B.V. All rights reserved.

Microwave oxidation treatment of sewage sludge.

PubMed

Lo, Kwang V; Srinivasan, Asha; Liao, Ping H; Bailey, Sam

2015-01-01

Microwave-oxidation treatment of sewage sludge using various oxidants was studied. Two treatment schemes with a combination of hydrogen peroxide and ozone were examined: hydrogen peroxide and ozone were introduced into the sludge simultaneously, followed by microwave heating. The other involved the ozonation first, and then the resulting solution was subjected to microwave and hydrogen peroxide treatment. The set with ozonation followed by hydrogen peroxide plus microwave heating yielded higher soluble materials than those of the set with hydrogen peroxide plus ozone first and then microwave treatment. No settling was observed for all treatments in the batch operation, except ozone/microwave plus hydrogen peroxide set at 120°C. The pilot-scale continuous-flow 915 MHz microwave study has demonstrated that microwave-oxidation process is feasible for real-time industrial application. It would help in providing key data for the design of a full-scale system for treating sewage sludge and the formulation of operational protocols.

Spectroscopic study of the effect of biological treatment on the humification process of sewage sludge

NASA Astrophysics Data System (ADS)

Polak, J.; Sułkowski, W. W.; Bartoszek, M.; Luty, A.; Pentak, D.; Sułkowska, A.

2007-05-01

In 2005 the treatment plant in Sosnowiec Zagórze was modernized and the processes of nitrification and denitrification were introduced. The study of the biological treatment influence on the course of the humification process was conducted for the sewage sludge received from each stage of sewage purification. The extracted humic-like substances (HA) were investigated by the use of the spectroscopic and analytical methods. The concentration of free radicals and the g-factor was determined with EPR, the presence of the characteristic functional groups was confirmed with IR spectroscopy, whereas the aromatisation of HA was estimated by 13C NMR method. The results obtained were compared with those for HA extracted from sewage sludge before modernization [1]. It was found that the processes of biological treatment have a significant influence on the changes of the chemical elements in the extracted HA. The HA obtained after modernization are nitrogen-rich (about 9%), in particular after the nitrification and denitrification processes. However, nitrification and denitrification processes only slightly affect the free radical concentration and the g-factor values.

Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

PubMed

Cristale, Joyce; Ramos, Dayana D; Dantas, Renato F; Machulek Junior, Amilcar; Lacorte, Silvia; Sans, Carme; Esplugas, Santiago

2016-01-01

This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L(-1) to 150 µg L(-1). During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g(-1) dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatment and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H2O2 and O3) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H2O2 and O3. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs. Copyright © 2015 Elsevier Inc. All rights reserved.

Land Application of Treated Sewage Sludge in the United States: Regulatory Considerations for Risk Reduction and Determining Treatment Process Equivalency

EPA Science Inventory

In the United States, municipal wastewater includes discharges from households, commercial businesses and various industries. Microorganisms associated with these wastes can be concentrated in the solids (sludge) which are removed during treatment operations. Beneficial reuse a...

Activated Sludge. Selected Instructional Activities and References. Instructional Resources Monograph Series.

ERIC Educational Resources Information Center

Shepard, Clinton L.; Walasek, James B.

This monograph contains a variety of selected materials related to wastewater treatment and water quality education and instruction. Part I presents a brief discussion of the activated sludge process in wastewater treatment operations. Part II, Instructional Units, contains selected portions of existing programs which may be utilized in…

Effect of Cambi Thermal Hydrolysis Process-Anaerobic digestion treatment on concentrations on phthalate plasticisers in wastewater sludge

USDA-ARS?s Scientific Manuscript database

The impact of the recently implemented Cambi Thermal Hydrolysis Process™-Anaerobic Digestion (TH-AD) solids treatment method on concentrations of 4 phthalate plasticisers in wastewater sludge samples was explored in this study. Samples were analysed for diisononyl phthalate (DiNP), diisodecyl phthal...

The effects of artificial ageing on the leaching behaviour of heavy metals in stabilized/solidified industrial sludge.

PubMed

Keskes, M; Choura, M; Rouis, J

2009-12-01

The use of a hydraulic binder for the treatment of mineral-based industrial wastes, containing heavy metals, by the chemical fixation and solidification (CFS) technique has raised serious questions regarding the prediction of the behaviour of these pollutants in the obtained solid matrix. It seems necessary, for this reason, to study the behaviour of these metals in response to leaching in order to evaluate their chemical speciation within the solidified sludge over the medium and long-terms. Within the framework of the current research, we applied the CFS technique to metallic hydroxide sludge, produced by the electrotyping surface treatment industry, by using Portland artificial cement (PAC). Compaction at the paste phase of this treated sludge resulted in up to 35% enhancement of the retention of pollutants, mainly trivalent chromium, in a cementing matrix, as compared with the classical technique that uses a simple vibration of sludge at the paste phase. The implemented process led to an improvement in the compactness of the sludge, and thus assured a better retention of heavy metals in response to the leaching of this treated sludge. The evaluation of the chemical properties of the materials obtained after an artificial ageing process using humidity variation cycles and thermal chocks also revealed a significant improvement in the retention capacity of heavy metals in the solidified sludge, which was mainly favoured by the development of carbonation. In fact, the release of the heavy metals from the above mentioned treated sludge was reduced by 58% for zinc and 51% for trivalent chromium after the artificial ageing process.

[Characteristics of odors and VOCs from sludge direct drying process].

PubMed

Chen, Wen-He; Deng, Ming-Jia; Luo, Hui; Zhang, Jing-Ying; Ding, Wen-Jie; Liu, Jun-Xin; Liu, Jun-Xin

2014-08-01

Co-processing sewage sludge by using the high-temperature feature of cement kiln can realize harmless disposal and energy recycling. In this paper, investigation on characteristics of the flue gas from sludge drying process was carried out in Guangzhou Heidelberg Yuexiu Cement Co., LTD. The composition and the main source of odors and volatile organic compounds (VOCs) emitted during the drying process were analyzed, aimed to provide scientific basis for the treatment of sewage sludge. Results showed that there were a large number of malodorous substances and VOCs in the flue gas. Sulfur dioxide and other sulfur-containing compounds were the main components in the malodorous substances, while benzene derivatives were predominant in VOCs. The compositions of odors and VOCs were influenced by the characteristics of the sludge and the heat medium (kiln tail gas). Total organic compounds in the sludge were significantly decreased after drying. Other organic substances such as volatile fatty acid, protein, and polysaccharide were also obviously reduced. The organic matter in sludge was the main source of VOCs in the flue gas. Part of sulfurous substances, such as sulfur dioxide, carbon disulfide, were from sulfur-containing substances in the sludge, and the rest were from the kiln tail gas itself.

Sanitary Landfill. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Sharman, Ronald M.

This lesson is an introduction to disposal of sludge by landfill. A brief explanation of the complete process is provided, including discussions of sludge suitability, site selection, method selection and operation, site closure, and ultimate reuse. The lesson includes an instructor's guide and student workbook. The instructor's guide contains a…

Sludge Incineration. Multiple Hearth. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Klopping, Paul H.

This lesson introduces the basics of sludge incineration and focuses on the multiple hearth furnace in accomplishing this task. Attention is given to component identification and function process control fundamentals, theory of incineration, safety, and other responsibilites of furnace operation. The material is rather technical and assumes an…

Leaching of Heavy Metals Using SPLP Method from Fired Clay Brick Incorporating with Sewage Sludge

NASA Astrophysics Data System (ADS)

Kadir, Aeslina Abdul; Salim, Nurul Salhana Abdul; Amira Sarani, Noor; Aqma Izurin Rahmat, Nur

2017-05-01

Sewage sludge is a by-product generate from wastewater treatment process. The sewage sludge contains significant trace metal such as Cr, Mn, Ni, Cu, Zn, As, Cd and Pb which are toxic to the environment. Sewage sludge is disposed of by landfilling method. However, this option not suitable because of land restriction and environmental control regulations imposed. Therefore, sewage sludge from wastewater treatment plant was incorporated into fired clay brick to produce good quality of brick as well as reducing heavy metals from sludge itself. Sewage sludge with 0%, 1%, 5%, 10% and 20% of were incorporated into fired clay bricks and fired at 1050°C temperature with heating rates of 1°C/min. The brick sample then crushed and sieved through 9.5 mm sieve for Synthetic Precipitation Leaching Procedure (SPLP). From the results, incorporation up to 20% of sewage sludge has leached less heavy metals and compliance with USEPA standard.

Deep dewatering process of sludge by chemical conditioning and its potential influence on wastewater treatment plants.

PubMed

Wang, Shuo; Ma, Cong; Zhu, Yin; Yang, Yangkun; Du, Guocheng; Li, Ji

2018-06-15

FeCl 3 , quick lime, and cationic polyacrylamide (CPAM) were used for excess sludge conditioning from wastewater treatment plant (WWTP) and the dewatering performance by different chemical conditioners was investigated. Experimental results showed that FeCl 3 could make small and concentrated sludge particles. Furthermore, new mineral phase structures for building a dewatering framework were obtained by the addition of quick lime, and the coagulation capacity was enhanced by the formation of colloid hydroxyl polymer, which was induced due to the alkaline environment. In addition, the floc particle size significantly increased after the CPAM dosage. The bound water could be released with the stripping of tightly bound extracellular polymeric substance (EPS). Therefore, the dewatering performance and efficiencies were improved and subsequently the hypothetical sludge deep dewatering process was depicted in accordance with the variation of EPS. However, high-strength refractory organics in sludge filtrates caused by quick lime pyrolysis could lead to the unstable operation of the WWTP, because the relatively high concentrations of organic compounds with benzene were dominant in sludge dewatering filtrates.

A novel conditioning process for enhancing dewaterability of waste activated sludge by combination of zero-valent iron and persulfate.

PubMed

Zhou, Xu; Wang, Qilin; Jiang, Guangming; Liu, Peng; Yuan, Zhiguo

2015-06-01

Improvement of sludge dewaterability is crucial for reducing the costs of sludge disposal in wastewater treatment plants. This study presents a novel conditioning method for improving waste activated sludge dewaterability by combination of persulfate and zero-valent iron. The combination of zero-valent iron (0-30g/L) and persulfate (0-6g/L) under neutral pH substantially enhanced the sludge dewaterability due to the advanced oxidization reactions. The highest enhancement of sludge dewaterability was achieved at 4g persulfate/L and 15g zero-valent iron/L, with which the capillary suction time was reduced by over 50%. The release of soluble chemical oxygen demand during the conditioning process implied the decomposition of sludge structure and microorganisms, which facilitated the improvement of dewaterability due to the release of bound water that was included in sludge structure and microorganism. Economic analysis showed that the proposed conditioning process with persulfate and ZVI is more economically favorable for improving WAS dewaterability than classical Fenton reagent. Copyright © 2015 Elsevier Ltd. All rights reserved.

From municipal/industrial wastewater sludge and FOG to fertilizer: A proposal for economic sustainable sludge management.

PubMed

Bratina, Božidar; Šorgo, Andrej; Kramberger, Janez; Ajdnik, Urban; Zemljič, Lidija Fras; Ekart, Janez; Šafarič, Riko

2016-12-01

After a ban on the depositing of untreated sludge in landfills, the sludge from municipal and industrial water-treatment plants can be regarded as a problem. Waste products of the water treatment process can be a problem or an opportunity - a source for obtaining raw materials. In the European Union, raw sludge and fats, oil and grease (FOG) from municipal and industrial wastewater treatment plants (WWTP) cannot be deposited in any natural or controlled environment. For this reason, it must be processed (stabilized, dried) to be used later as a fertilizer, building material, or alternative fuel source suitable for co-incineration in high temperature furnaces (power plants or concrete plants). The processes of drying sludge, where heat and electricity are used, are energy consuming and economically unattractive. Beside energy efficiency, the main problem of sludge drying is in its variability of quality as a raw material. In addition to this, sludge can be contaminated by a number of organic and inorganic pollutants and organisms. Due to the presence or absence of pollutants, different end products can be economically interesting. For example, if the dried sludge contains coliform bacteria, viruses, helminths eggs or smaller quantities of heavy metals, it cannot be used as a fertilizer but can still be used as a fuel. The objectives of the current article is to present a batch-processing pilot device of sludge or digestate that allows the following: (1) low pressure and low temperature energy effective drying of from 10 to 40% remaining water content, (2) disinfection of pathogen (micro)organisms, (3) heavy metal reduction, (4) production of products of predetermined quality (e.g. containing different quantities of water; it can be used as a fertilizer, or if the percentage of water in the dry sludge is decreased to 10%, then the dried sludge can be used as a fuel with a calorific value similar to coal). An important feature is also the utilization of low-pressure technology to prevent odorous gasses from spreading into the environment. There are presented two new technologies: a) Sewage sludge or digestate drying in the vacuum chamber consumes approx. 1 kWh/dm 3 of evaporated water and, therefore, reaches a price of 180-240 Euros/t Dry Matter (DM), and b) Heavy metals' reduction using adsorbing reaction with magnetite nanostructures can decrease the level of heavy metals in the sewage sludge or digestate up to 20% in one cycle, which can be repeated several times on the same sludge. The aim of the paper is to present a newly developed technology which can provide economic and safe use of moderate heavy metals polluted sewage sludge on agricultural lands as organic fertilizer and, therefore, returning the nutrients (nitrogen, phosphorous, potassium) back to the human food chain, instead of being incinerated or landfilled. The proposed drying technology is economically sustainable due to the low vacuum and temperature (35 °C-40 °C), that increases the efficiency of the heat pump (coefficient of performance 5-7,2) of the energy produced by the anaerobic digestion. Hence, the main emphasis is given to the development of: an efficient method for heavy metals' reduction in the sludge treatment chain by using chitosan covered magnetite nanoparticles, an efficient drying method in a vacuum with low temperature energy which can be exploited from sludge digestion to reduce organic matter, and an energy sustainable concept of sludge treatment, with the addition of fats, oil and grease (FOG) to produce enough biogas for sludge drying to produce fertilizer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of Anabaena flos-aquae in water treatment process using Moringa oleifera and assessment of fatty acid profile of generated sludge.

PubMed

Moreti, Livia O R; Coldebella, Priscila Ferri; Camacho, Franciele P; Carvalho Bongiovani, Milene; Pereira de Souza, Aloisio Henrique; Kirie Gohara, Aline; Matsushita, Makoto; Fernandes Silva, Marcela; Nishi, Letícia; Bergamasco, Rosângela

2016-01-01

This study aimed to evaluate the efficiency of the coagulation/flocculation/dissolved air flotation (C/F/DAF) process using the coagulant Moringa oleifera (MO) seed powder, and to analyse the profile of fatty acids present in the generated sludge after treatment. For the tests, deionized water artificially contaminated with cell cultures of Anabaena flos-aquae was used, with a cell density in the order of 10(4) cells mL(-1). C/F/DAF tests were conducted using 'Flotest' equipment. For fatty acid profile analyses, a gas chromatograph equipped with a flame ionization detector was used. It was seen that the optimal dosage (100 mg L(-1)) of MO used in the C/F/DAF process was efficient at removing nearly all A. flos-aquae cells (96.4%). The sludge obtained after treatment contained oleic acid (61.7%) and palmitic acid (10.8%). Thus, a water treatment process using C/F/DAF linked to integral MO powder seed was found to be efficient in removing cells of cyanobacteria, and produced a sludge rich in oleic acid that is a precursor favourable for obtaining quality biodiesel, thus becoming an alternative application for the recycling of such biomass.

Anaerobic digestion of thermal pre-treated sludge at different solids concentrations--Computation of mass-energy balance and greenhouse gas emissions.

PubMed

Pilli, Sridhar; More, Tanaji; Yan, Song; Tyagi, Rajeshwar Dayal; Surampalli, Rao Y

2015-07-01

The effect of thermal pre-treatment on sludge anaerobic digestion (AD) efficiency was studied at different total solids (TS) concentrations (20.0, 30.0 and 40.0 g TS/L) and digestion times (0, 5, 10, 15, 20 and 30 days) for primary, secondary and mixed wastewater sludge. Moreover, sludge pre-treatment, AD and disposal processes were evaluated based on a mass-energy balance and corresponding greenhouse gas (GHG) emissions. Mass balance revealed that the least quantity of digestate was generated by thermal pre-treated secondary sludge at 30.0 g TS/L. The net energy (energy output-energy input) and energy ratio (energy output/energy input) for thermal pre-treated sludge was greater than control in all cases. The reduced GHG emissions of 73.8 × 10(-3) g CO2/g of total dry solids were observed for the thermal pre-treated secondary sludge at 30.0 g TS/L. Thermal pre-treatment of sludge is energetically beneficial and required less retention time compared to control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals.

PubMed

Falås, P; Baillon-Dhumez, A; Andersen, H R; Ledin, A; la Cour Jansen, J

2012-03-15

Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct difference between nitrifying activated sludge and suspended biofilm carrier removal of several pharmaceuticals was demonstrated. Biofilm carriers from full-scale nitrifying wastewater treatment plants, demonstrated considerably higher removal rates per unit biomass (i.e. suspended solids for the sludges and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast to the pharmaceutical removal, the nitrification capacity per unit biomass was lower for the carriers than the sludges, which suggests that neither the nitrite nor the ammonia oxidizing bacteria are primarily responsible for the observed differences in pharmaceutical removal. The low ability of ammonia oxidizing bacteria to degrade or transform the target pharmaceuticals was further demonstrated by the limited pharmaceutical removal in an experiment with continuous nitritation and biofilm carriers from a partial nitritation/anammox sludge liquor treatment process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Study on Treatment of acidic and highly concentrated fluoride waste water using calcium oxide-calcium chloride

NASA Astrophysics Data System (ADS)

Ren, T.; Gao, X. R.; Zheng, T.; Wang, P.

2016-08-01

There are problems with treating acidic waste water containing high concentration fluorine by chemical precipitation, including the low sludge setting velocity and the high difficulty of reaching the criterion. In Heilongjiang province, a graphite factory producing high-purity graphite generates acidic waste water with a high concentration of fluorine. In this paper, the effect of removals on the concentration of fluoride with the combined treatment of calcium oxide and calcium chloride were discussed with regard to acid waste water. The study improved the sludge characteristics by using polyacrylamide (PAM) and polymeric aluminum chloride (PAC). The effect of different coagulants on sludge was evaluated by the sludge settlement ratio (SV), sludge volume index (SVI) and sludge moisture content. The results showed that the optimal combination for 100 ml waste water was calcium oxide addition amount of 14 g, a calcium chloride addition amount of 2.5 g, a PAM addition amount of 350 mg/L, and the effluent fluoride concentration was below 6 mg/L. PAM significantly improved the sludge settling velocity. The sludge settlement ratio reduced from 87.6% to 60%. The process for wastewater treatment was easily operated and involved low expenditure.

Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

PubMed

Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

2015-12-01

This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anionic surfactants in treated sewage and sludges: risk assessment to aquatic and terrestrial environments.

PubMed

Mungray, Arvind Kumar; Kumar, Pradeep

2008-05-01

Compared to low concentrations of anionic surfactants (AS) in activated sludge process effluents (ASP) (<0.2 mg/L), upflow anaerobic sludge blanket-polishing pond (UASB-PP) effluents were found to contain very high concentrations of AS (>3.5 mg/L). AS (or linear alkylbenzen sulfonate, LAS) removals >99% have been found for ASP while in case of UASB-PP it was found to be < or = 30%. AS concentrations averaged 7347 and 1452 mg/kg dry wt. in wet UASB and dried sludges, respectively. Treated sewage from UASB based sewage treatment plants (STPs) when discharged to aquatic ecosystems are likely to generate substantial risk. Post-treatment using 1-1.6d detention, anaerobic, non-algal polishing ponds was found ineffective. Need of utilizing an aerobic method of post-treatment of UASB effluent in place of an anaerobic one has been emphasized. Natural drying of UASB sludges on sludge drying beds (SDBs) under aerobic conditions results in reduction of adsorbed AS by around 80%. Application of UASB sludges on SDBs was found simple, economical and effective. While disposal of treated UASB effluent may cause risk to aquatic ecosystems, use of dried UASB sludges is not likely to cause risk to terrestrial ecosystems.

Operational Control Procedures for the Activated Sludge Process: Appendix.

ERIC Educational Resources Information Center

West, Alfred W.

This document is the appendix for a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. Categories discussed include: control test data, trend charts, moving averages, semi-logarithmic plots, probability…

Multi-step process for concentrating magnetic particles in waste sludges

DOEpatents

Watson, John L.

1990-01-01

This invention involves a multi-step, multi-force process for dewatering sludges which have high concentrations of magnetic particles, such as waste sludges generated during steelmaking. This series of processing steps involves (1) mixing a chemical flocculating agent with the sludge; (2) allowing the particles to aggregate under non-turbulent conditions; (3) subjecting the mixture to a magnetic field which will pull the magnetic aggregates in a selected direction, causing them to form a compacted sludge; (4) preferably, decanting the clarified liquid from the compacted sludge; and (5) using filtration to convert the compacted sludge into a cake having a very high solids content. Steps 2 and 3 should be performed simultaneously. This reduces the treatment time and increases the extent of flocculation and the effectiveness of the process. As partially formed aggregates with active flocculating groups are pulled through the mixture by the magnetic field, they will contact other particles and form larger aggregates. This process can increase the solids concentration of steelmaking sludges in an efficient and economic manner, thereby accomplishing either of two goals: (a) it can convert hazardous wastes into economic resources for recycling as furnace feed material, or (b) it can dramatically reduce the volume of waste material which must be disposed.

Multi-step process for concentrating magnetic particles in waste sludges

DOEpatents

Watson, J.L.

1990-07-10

This invention involves a multi-step, multi-force process for dewatering sludges which have high concentrations of magnetic particles, such as waste sludges generated during steelmaking. This series of processing steps involves (1) mixing a chemical flocculating agent with the sludge; (2) allowing the particles to aggregate under non-turbulent conditions; (3) subjecting the mixture to a magnetic field which will pull the magnetic aggregates in a selected direction, causing them to form a compacted sludge; (4) preferably, decanting the clarified liquid from the compacted sludge; and (5) using filtration to convert the compacted sludge into a cake having a very high solids content. Steps 2 and 3 should be performed simultaneously. This reduces the treatment time and increases the extent of flocculation and the effectiveness of the process. As partially formed aggregates with active flocculating groups are pulled through the mixture by the magnetic field, they will contact other particles and form larger aggregates. This process can increase the solids concentration of steelmaking sludges in an efficient and economic manner, thereby accomplishing either of two goals: (a) it can convert hazardous wastes into economic resources for recycling as furnace feed material, or (b) it can dramatically reduce the volume of waste material which must be disposed. 7 figs.

Energy and nutrient recovery from anaerobic treatment of organic wastes

NASA Astrophysics Data System (ADS)

Henrich, Christian-Dominik

The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an "Ammonia Recovery Process" (ARP) consisting of: (1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, (2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, (3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, (4) high-rate algal post-treatment and finally, (5) an optional anaerobic digestion process for algal and bacterial biomass, and/or supplemental waste fermentation providing the potential for additional nutrient and energy recovery. In addition, the value provided by the waste treatment function of the overall processes, each of the sub-processes would provide valuable co-products offering potential GHG credit through direct fossil-fuel replacement, or replacement of products requiring fossil fuels. These valuable co-products include, (1) ammonium sulfate fertilizer, (2) bacterial biomass, (3) algal biomass providing, high-protein feeds and oils for biodiesel production and, (4) methane bio-fuels. Laboratory and pilot reactors were constructed and operated, providing data supporting the quantification and modeling of the ARP. Growth parameters, and stoichiometric coefficients were determined, allowing for design of the leachate activated sludge treatment sub-component. Laboratory and pilot algal reactors were constructed and operated, and provided data that supported the determination of leachate organic/inorganic-nitrogen ratio, and loading rates, allowing optimum performance of high-rate algal post-treatment. A modular and expandable computer program was developed, which provided a systems model framework capable of predicting individual component and overall performance. The overall systems model software, ENRAT, predicted that a full-scale operation to treat 18,750 L leachate/day would need an Ammonia Recovery process consisting of 88,300 L of total gas transfer column volume, an activated sludge system of 74,417 L, and an algal post treatment raceway of 683 m2 (30 cm depth). The ARP would consume 262.5 L/day of 6N sulfuric acid and produce 16.12 kg-N/day ammonium sulfate. The activated sludge system and algal post treatment would produce 900 g-VS/day (or 44.6 L 2% sludge) and 6.83 kg-VS/day (or 341.6 L 2% sludge) of bacterial and algal biomass.

Effects of chemical sludge disintegration on the performances of wastewater treatment by membrane bioreactor.

PubMed

Oh, Young-Khee; Lee, Ki-Ryong; Ko, Kwang-Baik; Yeom, Ick-Tae

2007-06-01

A new wastewater treatment process combining a membrane bioreactor (MBR) with chemical sludge disintegration was tested in bench scale experiments. In particular, the effects of the disintegration treatment on the excess sludge production in MBR were investigated. Two MBRs were operated. In one reactor, a part of the mixed liquor was treated with NaOH and ozone gas consecutively and was returned to the bioreactor. The flow rate of the sludge disintegration stream was 1.5% of the influent flow rate. During the 200 days of operation, the MLSS level in the bioreactor with the disintegration treatment was maintained relatively constant at the range of 10,000-11,000 mg/L while it increased steadily up to 25,000 mg/L in the absence of the treatment. In the MBR with the sludge disintegration, relatively constant transmembrane pressures (TMPs) could be maintained for more than 6 months while the MBR without disintegration showed an abrupt increase of TMP in the later phase of the operation. In conclusion, a complete control of excess sludge production in the membrane-coupled bioreactor was possible without significant deterioration of the treated water quality and membrane performances.

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments.

PubMed

Ouardani, Imen; Turki, Syrine; Aouni, Mahjoub; Romalde, Jesús L

2016-07-01

Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem. Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated. Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 10(3) genome copies [GC]/ml) and influents (2.7 × 10(3) GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did. Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater. This report provides important data on the incidence, behavior, seasonality, and genotype distribution of HAV in the environment in Tunisia, as well as the risk of infection derived from its occurrence in effluents due to inadequate wastewater treatment. In addition, these findings seem to confirm that the prevalence of HAV depends on socioeconomic level, sanitary conditions in the communities, sewage facilities, the locality, and the climate. The wide dispersion of HAV in effluents proves the inefficacity of the current wastewater treatment processes used in Tunisia to remove virus; therefore, establishment of tertiary treatment processes or replacement of the medium-charge activated sludge (conventional activated sludge) by the low-charge version (oxidation ditch activated sludge) is absolutely needed. Rapid detection of the HAV genome in wastewater may provide a timely warning sign to health authorities to implement population protection measures. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Parasite contamination (helminth eggs) in sludge treatment plants: definition of a sampling strategy.

PubMed

Gaspard, Philippe G; Schwartzbrod, Janine

2003-03-01

The use of sludge in agriculture must be carried out according to many guidelines, especially regarding a precise knowledge of the pathogenic microorganisms it contains. The control of the produced sludge requires a sampling strategy that is representative of the contamination present in the sludge. Thus, we evaluated the distribution of helminth eggs in sludge to determine how to sample and at what frequency. Two plants were studied, firstly we studied sludge that was undergoing biological treatment (anaerobic digestion, prolonged aeration), secondly we evaluated the dehydration step (centrifugation and filter press). The helminth egg concentrations were measured over short periods (between 5 minutes and 7 hours) and for periods of over 24 hours (7 to 28 days). The results showed that there was much homogeneity in periods of less than 7 hours, thus it was advisable to take grab samples. An appropriate sample weight was 30 g dry matter, because this allowed an analysis in triplicate when testing treatment processes according to standards of France, (less than 3 viable eggs/10 g dry matter). Determination of the egg concentration in the plants during periods of over 24 hours showed that the parasite flow was stable. In some cases, large variations were due to the treatment processes (storage or thickening, mixing of different sludges). These results have been confirmed with the study of 6 other plants during a one year period. Thus, the recommended sampling frequency can be limited to every 3 to 6 months, by adapting the sampling methods to the characteristics of the plant.

Degradation of organophosphate esters in sewage sludge: Effects of aerobic/anaerobic treatments and bacterial community compositions.

PubMed

Pang, Long; Ge, Liming; Yang, Peijie; He, Han; Zhang, Hongzhong

2018-05-01

In this study, the degradation of organophosphate esters (OPEs) in sewage sludge with aerobic composting and anaerobic digestion was investigated. The total concentrations of six OPEs (ΣOPEs) in the whole treatment process reduced in the order of anaerobic digestion combined with pig manure (T3) > aerobic composting combined with pig manure (T1) > aerobic composting (T2) > anaerobic digestion (T4). The addition of pig manure significantly enhanced the removal rate of OPEs in both aerobic and anaerobic treatments. The abundance and diversity of bacterial community reduced after the treatment process. Shannon index, principal component analysis, network analysis, and heat map further confirmed the variation of bacterial community compositions among different treatments. Five genera (i.e., Flavobacterium, Bacillus, Alcaligene, Pseudomonas, and Bacillus megaterium) might be responsible for the degradation of OPE compounds in sewage sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Verification of vermural stabilization of ash from biomass and sewage sludge

NASA Astrophysics Data System (ADS)

Adamkova, L.; Kucerova, D.; Lyckova, B.; Kucerova, R.; Takac, D.

2017-10-01

The aim of this study was to find dependence on biofuels and sludge from sewage treatment plants in the vermicomposting process. In the framework of the research carried out at our workplace, a project aimed at finding an appropriate method for the reprocessing of problematic biodegradable waste and asphalt from combustion biomass was used as a raw material for the production of rectification substrate and sludge from sewage treatment plants that could be used as Secondary raw material.

Anaerobic treatment of sludge from a nitrification-denitrification landfill leachate plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maranon, E.; Castrillon, L.; Fernandez, Y.

2006-07-01

The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400 mg O{sub 2} dm{sup -3}, in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9 l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1more » cm{sup 3} dm{sup -3} of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented {approx}16% of the volume of the treated sludge.« less

A full scale worm reactor for efficient sludge reduction by predation in a wastewater treatment plant.

PubMed

Tamis, J; van Schouwenburg, G; Kleerebezem, R; van Loosdrecht, M C M

2011-11-15

Sludge predation can be an effective solution to reduce sludge production at a wastewater treatment plant. Oligochaete worms are the natural consumers of biomass in benthic layers in ecosystems. In this study the results of secondary sludge degradation by the aquatic Oligochaete worm Aulophorus furcatus in a 125 m(3) reactor and further sludge conversion in an anaerobic tank are presented. The system was operated over a period of 4 years at WWTP Wolvega, the Netherlands and was fed with secondary sludge from a low loaded activated sludge process. It was possible to maintain a stable and active population of the aquatic worm species A. furcatus during the full period. Under optimal conditions a sludge conversion of 150-200 kg TSS/d or 1.2-1.6 kg TSS/m(3)/d was established in the worm reactor. The worms grew as a biofilm on carrier material in the reactor. The surface specific conversion rate reached 140-180 g TSS/m(2)d and the worm biomass specific conversion rate was 0.5-1 g TSS sludge/g dry weight worms per day. The sludge reduction under optimal conditions in the worm reactor was 30-40%. The degradation by worms was an order of magnitude larger than the endogenous conversion rate of the secondary sludge. Effluent sludge from the worm reactor was stored in an anaerobic tank where methanogenic processes became apparent. It appeared that besides reducing the sludge amount, the worms' activity increased anaerobic digestibility, allowing for future optimisation of the total system by maximising sludge reduction and methane formation. In the whole system it was possible to reduce the amount of sludge by at least 65% on TSS basis. This is a much better total conversion than reported for anaerobic biodegradability of secondary sludge of 20-30% efficiency in terms of TSS reduction. Copyright © 2011 Elsevier Ltd. All rights reserved.

Determination of the priority indexes for the oil refinery wastewater treatment process

NASA Astrophysics Data System (ADS)

Chesnokova, M. G.; Myshlyavtsev, A. V.; Kriga, A. S.; Shaporenko, A. P.; Markelov, V. V.

2017-08-01

The wastewater biological treatment intensity and effectiveness are influenced by many factors: temperature, pH, presence and concentration of toxic substances, the biomass concentration et al. Regulation of them allows controlling the biological treatment process. Using the Bayesian theorem the link between changes was determined and the wastewater indexes normative limits exceeding influence for activated sludge characteristics alteration probability was evaluated. The estimation of total, or aposterioric, priority index presence probability, which characterizes the wastewater treatment level, is an important way to use the Bayesian theorem in activated sludge swelling prediction at the oil refinery biological treatment unit.

Septage unit treatment by sludge treatment reed beds for easy management and reuse: performance and design considerations.

PubMed

Kim, Boram; Bel, Thomas; Bourdoncle, Pascal; Dimare, Jocelyne; Troesch, Stéphane; Molle, Pascal

2018-01-01

Sustainable treatment and management of fecal sludge in rural areas require adapted solutions. Rustic and simple operating processes such as sludge treatment reed beds (STRB) have been increasingly considered for this purpose. The biggest full scale (2,600 m 2 of STRB) septage treatment unit in France had been built in Nègrepelisse with the final objectives of reusing treated sludge and leachates for agriculture spreading and tree irrigation, respectively. The aim of this investigation was to validate the treatment chain of this installation. The obtained field data showed firstly that the overall removal efficiencies of STRB were satisfactory and stable. Removal rates higher than 98% for chemical oxygen demand and suspended solids and a 95% for Kjeldahl nitrogen represented so far a beneficial septage treatment by STRB. The highlighted necessity of a suitable complementary leachate treatment (before tree irrigation) justified the presence of the second stage of vertical flow constructed wetland. The sludge deposit drying and mineralization efficiencies were on the right track. According to hydrotextural diagram analysis, surface deposit was however found to have high deformability probably due to the youth of the installation. An in-depth understanding of STRB system needs continuous long-term studies.

Operational Control Procedures for the Activated Sludge Process, Part III-A: Calculation Procedures.

ERIC Educational Resources Information Center

West, Alfred W.

This is the second in a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. This document deals exclusively with the calculation procedures, including simplified mixing formulas, aeration tank…

Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Carnegie, John W., Ed.

This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

Effect of low temperature thermal pre-treatment on the solubilization of organic matter, pathogen inactivation and mesophilic anaerobic digestion of poultry sludge.

PubMed

Ruiz-Espinoza, Juan E; Méndez-Contreras, Juan M; Alvarado-Lassman, Alejandro; Martínez-Delgadillo, Sergio A

2012-01-01

Treatment of poultry industry effluents produces wastewater sludge with high levels of organic compounds and pathogenic microorganisms. In this research, the thermal pre-treatment of poultry slaughterhouse sludge (PSS) was evaluated for low temperatures in combination with different exposure times as a pre-hydrolysis strategy to improve the anaerobic digestion process. Organic compounds solubilization and inactivation of pathogenic microorganisms were evaluated after treatment at 70, 80 or 90°C for 30, 60 or 90 min. The results showed that 90°C and 90 min were the most efficient conditions for solubilization of the organic compounds (10%). In addition, the bacteria populations and the more resistant structures, such as helminth eggs (HE), were completely inactivated. Finally, the thermal pre-treatment applied to the sludge increased methane yield by 52% and reduced hydraulic retention time (HRT) by 52%.

An integrated AMBBR and IFAS-SBR process for municipal wastewater treatment towards enhanced energy recovery, reduced energy consumption and sludge production.

PubMed

Gu, Jun; Xu, Guangjing; Liu, Yu

2017-03-01

The conventional activated sludge (CAS) process has been widely employed for wastewater treatment for more than one hundred years. Recently, more and more concerns have been raised on the CAS process due to its high energy consumption and production of huge amount of waste activated sludge, which are inevitably linked to the issue of environmental sustainability and global climate change. Facing to such emerging and challenging situation, this study reported a novel A-B process in which an anaerobic moving bed biofilm reactor (AMBBR) served a lead A-stage for COD capture towards biogas production and an integrated fixed-biofilm and activated sludge sequencing batch reactor (IFAS-SBR) was employed as B-stage for biological nitrogen removal. Results showed that about 85% of wastewater COD was removed in the steady-state AMBBR with a total energy production rate of 0.28 kWh/m 3 wastewater treated, while 85% of N-removal was achieved when the stable nitrite shunt was established in the IFAS-SBR. Moreover, 90% of dissolved methane in the AMBBR effluent could be removed by the proposed flash chamber at the lower energy demand of 0.12 kWh/m 3 which could be offset by the potential energy harvested from produced methane. Compared to the CAS process, the production of waste sludge was reduced by about 75% in the proposed A-B process due to the efficient COD capture at the A-stage, leading to significant energy savings from aeration for COD oxidation and post-treatment of waste sludge at the B-stage. Consequently, this study offers in-depth insights into A-B process which should be considered as an ideal candidate for achieving the energy-neutral or even energy positive operation of a municipal wastewater treatment. Given the complex situation in A-B process, future study is needed to look into the system optimization towards the operational synergy between A- and B-stage in terms of energy recovery and nitrogen removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization, modeling and application of aerobic granular sludge for wastewater treatment.

PubMed

Liu, Xian-Wei; Yu, Han-Qing; Ni, Bing-Jie; Sheng, Guo-Ping

2009-01-01

Recently extensive studies have been carried out to cultivate aerobic granular sludge worldwide, including in China. Aerobic granules, compared with conventional activated sludge flocs, are well known for their regular, dense, and strong microbial structure, good settling ability, high biomass retention, and great ability to withstand shock loadings. Studies have shown that the aerobic granules could be applied for the treatment of low- or high-strength wastewaters, simultaneous removal of organic carbon, nitrogen and phosphorus, and decomposition of toxic wastewaters. Thus, this new form of activate sludge, like anaerobic granular sludge, could be employed for the treatment of municipal and industrial wastewaters in near future. This chapter attempts to provide an up-to-date review on the definition, cultivation, characterization, modeling and application of aerobic granular sludge for biological wastewater treatment. This review outlines some important discoveries with regard to the factors affecting the formation of aerobic granular sludge, their physicochemical characteristics, as well as their microbial structure and diversity. It also summarizes the modeling of aerobic granule formation. Finally, this chapter highlights the applications of aerobic granulation technology in the biological wastewater treatment. It is concluded that the knowledge regarding aerobic granular sludge is far from complete. Although previous studies in this field have undoubtedly improved our understanding on aerobic granular sludge, it is clear that much remains to be learned about the process and that many unanswered questions still remain. One of the challenges appears to be the integration of the existing and growing scientific knowledge base with the observations and applications in practice, which this paper hopes to partially achieve.

Characterization, Modeling and Application of Aerobic Granular Sludge for Wastewater Treatment

NASA Astrophysics Data System (ADS)

Liu, Xian-Wei; Yu, Han-Qing; Ni, Bing-Jie; Sheng, Guo-Ping

Recently extensive studies have been carried out to cultivate aerobic granular sludge worldwide, including in China. Aerobic granules, compared with conventional activated sludge flocs, are well known for their regular, dense, and strong microbial structure, good settling ability, high biomass retention, and great ability to withstand shock loadings. Studies have shown that the aerobic granules could be applied for the treatment of low- or high-strength wastewaters, simultaneous removal of organic carbon, nitrogen and phosphorus, and decomposition of toxic wastewaters. Thus, this new form of activate sludge, like anaerobic granular sludge, could be employed for the treatment of municipal and industrial wastewaters in near future. This chapter attempts to provide an up-to-date review on the definition, cultivation, characterization, modeling and application of aerobic granular sludge for biological wastewater treatment. This review outlines some important discoveries with regard to the factors affecting the formation of aerobic granular sludge, their physicochemical characteristics, as well as their microbial structure and diversity. It also summarizes the modeling of aerobic granule formation. Finally, this chapter highlights the applications of aerobic granulation technology in the biological wastewater treatment. It is concluded that the knowledge regarding aerobic granular sludge is far from complete. Although previous studies in this field have undoubtedly improved our understanding on aerobic granular sludge, it is clear that much remains to be learned about the process and that many unanswered questions still remain. One of the challenges appears to be the integration of the existing and growing scientific knowledge base with the observations and applications in practice, which this paper hopes to partially achieve.

Rise Time. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

ERIC Educational Resources Information Center

Carnegie, John W.

The rise time test (along with the settleometer procedure) is used to monitor sludge behavior in the secondary clarifier of an activated sludge system. The test monitors the effect of the nitrification/denitrification process and aids the operator in determining optimum clarifier sludge detention time and, to some extent, optimum degree of…

Evaluation of the Removal of Indicator Bacteria from Domestic Sludge Processed by Autothermal Thermophilic Aerobic Digestion (ATAD)

PubMed Central

Piterina, Anna V.; Bartlett, John; Pembroke, Tony J.

2010-01-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing. PMID:20948933

Evaluation of the removal of indicator bacteria from domestic sludge processed by Autothermal Thermophilic Aerobic Digestion (ATAD).

PubMed

Piterina, Anna V; Bartlett, John; Pembroke, Tony J

2010-09-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing.

Anaerobic bioremediation of hexavalent uranium in groundwater by reductive precipitation with methanogenic granular sludge.

PubMed

Tapia-Rodriguez, Aida; Luna-Velasco, Antonia; Field, Jim A; Sierra-Alvarez, Reyes

2010-04-01

Uranium has been responsible for extensive contamination of groundwater due to releases from mill tailings and other uranium processing waste. Past evidence has confirmed that certain bacteria can enzymatically reduce soluble hexavalent uranium (U(VI)) to insoluble tetravalent uranium (U(IV)) under anaerobic conditions in the presence of appropriate electron donors. This paper focuses on the evaluation of anaerobic granular sludge as a source of inoculum for the bioremediation of uranium in water. Batch experiments were performed with several methanogenic anaerobic granular sludge samples and different electron donors. Abiotic controls consisting of heat-killed inoculum and non-inoculated treatments confirmed the biological removal process. In this study, unadapted anaerobic granular sludge immediately reduced U(VI), suggesting an intrinsic capacity of the sludge to support this process. The high biodiversity of anaerobic granular sludge most likely accounts for the presence of specific microorganisms capable of reducing U(VI). Oxidation by O(2) was shown to resolubilize the uranium. This observation combined with X-ray diffraction evidence of uraninite confirmed that the removal during anaerobic treatment was due to reductive precipitation. The anaerobic removal activity could be sustained after several respikes of U(VI). The U(VI) removal was feasible without addition of electron donors, indicating that the decay of endogenous biomass substrates was contributing electron equivalents to the process. Addition of electron donors, such as H(2) stimulated the removal of U(VI) to varying degrees. The stimulation was greater in sludge samples with lower endogenous substrate levels. The present work reveals the potential application of anaerobic granular sludge for continuous bioremediation schemes to treat uranium-contaminated water. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

A review on sludge dewatering indices.

PubMed

To, Vu Hien Phuong; Nguyen, Tien Vinh; Vigneswaran, Saravanamuth; Ngo, Huu Hao

2016-01-01

Dewatering of sludge from sewage treatment plants is proving to be a significant challenge due to the large amounts of residual sludges generated annually. In recent years, research and development have focused on improving the dewatering process in order to reduce subsequent costs of sludge management and transport. To achieve this goal, it is necessary to establish reliable indices that reflect the efficiency of sludge dewatering. However, the evaluation of sludge dewaterability is not an easy task due to the highly complex nature of sewage sludge and variations in solid-liquid separation methods. Most traditional dewatering indices fail to predict the maximum cake solids content achievable during full-scale dewatering. This paper reviews the difficulties in assessing sludge dewatering performance, and the main techniques used to evaluate dewatering performance are compared and discussed in detail. Finally, the paper suggests a new dewatering index, namely the modified centrifugal index, which is demonstrated to be an appropriate indicator for estimating the final cake solids content as well as simulating the prototype dewatering process.

Rain events and their effect on effluent quality studied at a full scale activated sludge treatment plant.

PubMed

Wilén, B M; Lumley, D; Mattsson, A; Mino, T

2006-01-01

The effect of rain events on effluent quality dynamics was studied at a full scale activated sludge wastewater treatment plant which has a process solution incorporating pre-denitrification in activated sludge with post-nitrification in trickling filters. The incoming wastewater flow varies significantly due to a combined sewer system. Changed flow conditions have an impact on the whole treatment process since the recirculation to the trickling filters is set by the hydraulic limitations of the secondary settlers. Apart from causing different hydraulic conditions in the plant, increased flow due to rain or snow-melting, changes the properties of the incoming wastewater which affects process performance and effluent quality, especially the particle removal efficiency. A comprehensive set of on-line and laboratory data were collected and analysed to assess the impact of rain events on the plant performance.

Water quality management library. 2. edition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eckenfelder, W.W.; Malina, J.F.; Patterson, J.W.

1998-12-31

A series of ten books offered in conjunction with Water Quality International, the Biennial Conference and Exposition of the International Association on Water Pollution Research and Control (IAWPRC). Volume 1, Activated Sludge Process, Design and Control, 2nd edition, 1998: Volume 2, Upgrading Wastewater Treatment Plants, 2nd edition, 1998: Volume 3, Toxicity Reduction, 2nd edition, 1998: Volume 4, Municipal Sewage Sludge Management, 2nd edition, 1998: Volume 5, Design and Retrofit of Wastewater Treatment Plants for Biological Nutrient Removal, 1st edition, 1992: Volume 6, Dynamics and Control of the Activated Sludge Process, 2nd edition, 1998: Volume 7: Design of Anaerobic Processes formore » the Treatment of Industrial and Municipal Wastes, 1st edition, 1992: Volume 8, Groundwater Remediation, 1st edition, 1992: Volume 9, Nonpoint Pollution and Urban Stormwater Management, 1st edition, 1995: Volume 10, Wastewater Reclamation and Reuse, 1st edition, 1998.« less

Modified anaerobic digestion elutriated phased treatment for the anaerobic co-digestion of sewage sludge and food wastewater.

PubMed

Mo, Kyung; Lee, Wonbae; Kim, Moonil

2017-02-01

A modified anaerobic digestion elutriated phased treatment (MADEPT) process was developed for investigating anaerobic co-digestion of sewage sludge and food wastewater. The anaerobic digestion elutriated phased treatment (ADEPT) process is similar to a two-phase system, however, in which the effluent from a methanogenic reactor recycles into an acidogenic reactor to elutriate mainly dissolved organics. Although ADEPT could reduce reactor volume significantly, the unsolubilized solids should be wasted from the system. The MADEPT process combines thermo-alkali solubilization with ADEPT to improve anaerobic performance and to minimize the sludge disposal. It was determined that the optimal volume mixing ratio of sewage sludge and food wastewater was 4 : 1 for the anaerobic co-digestion. The removal efficiencies of total chemical oxygen demand, volatile solids, and volatile suspended solids in the MADEPT process were 73%, 70%, and 64%, respectively. However, those in the ADEPT process were only 48%, 37%, and 40%, respectively, at the same hydraulic retention time (HRT) of 7 days. The gas production of MADEPT was two times higher than that of ADEPT. The thermo-alkali solubilization increased the concentration of dissolved organics so that they could be effectively degraded in a short HRT, implying that MADEPT could improve the performance of ADEPT in anaerobic co-digestion.

Monitoring the fate and behavior of TiO2 nanoparticles: Simulated in a WWTP with industrial dye-stuff effluent according to OECD 303A.

PubMed

Mahlalela, Lwazi C; Ngila, Jane C; Dlamini, Langelihle N

2017-07-03

The use of nanoparticles (NPs) in several consumer products has led to them finding their way into wastewater treatment plants (WWTPs). Some of these NPs have photocatalytic properties, thus providing a possible solution to textile industries to photodegrade dyes from their wastewater. Thus, the interaction of NPs with industrial dye effluents is inevitable. The Organization for Economic Co-operation and development (OECD) guideline for testing of chemical 303A was employed to study the fate and behaviour of TiO 2 NPs in industrial dye-stuff effluent. This was due to the unavailability of NPs' fate and behaviour test protocols. The effect of TiO 2 NPs on the treatment process was ascertained by measuring chemical oxygen demand (COD) and 5-day biological oxygen demand (BOD5). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to study the fate and behavior of TiO 2 NPs. Acclimatization of bacteria to target pollutants was a crucial factor for the treatment efficiency of activated sludge in a simulated wastewater treatment plant (SWTP). The acclimatization of the activated sludge to the synthetic industrial dye-stuff effluent was successfully achieved. Effect of TiO 2 NPs on the treatment process efficiency was then investigated. Addition of TiO 2 NPs had no effect on the treatment process as chemical oxygen demand (COD) removal remained >80%. Measured total plate count (TPC) affirmed that the addition of TiO 2 NPs had no effect on the treatment process. The removal of total nitrogen (TN) was not efficient as the treatment system was required to have an oxic and anoxic stage for efficient TN removal. Results from X-ray powder diffraction (XRD) confirmed that the anatase phase of the added TiO 2 NPs remained unchanged even after exposure to the treatment plant. Removal of the NPs from the influent was facilitated by biosorption of the NPs on the activated sludge. Nanoparticles received by wastewater treatment plants will therefore reach the environment through sludge waste dumped in landfill. About 90% of TiO 2 was retained in the activated sludge, and 10-11% escaped with the treated effluents. Scanning electron microscope (SEM) mapping micrographs together with an energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Ti in the sludge.

Multi-spectral and thermodynamic analysis of the interaction mechanism between Cu2+ and α-amylase and impact on sludge hydrolysis.

PubMed

Zhou, Ruiqi; Liu, Hong; Hou, Guangying; Ju, Lei; Liu, Chunguang

2017-04-01

An increasing amount of heavy metals (e.g., Cu 2+ ) is being discharged into sewage treatment plants and is accumulating in sludge, which is toxic to the enzyme in sludge or soil when the sludge is used as fertilizer, resulting in unfavorable effect on the biological treatment of sludge and the circulation and conversion of materials in soil. In this research, effect of Cu 2+ on sludge hydrolysis by α-amylase is studied from the respect of concentration and components of soluble organic matter in sludge, using three-dimensional fluorescence spectra. Results show that Cu 2+ exposure not only inhibits the hydrolysis of sludge due to the denaturation of α-amylase but also affects the components of soluble organic matter in sludge. In order to illuminate the interaction mechanism between Cu 2+ and α-amylase (a model of hydrolase in sludge), multi-spectra and isothermal titration microcalorimetry techniques are applied. Results show that the secondary structure of α-amylase is changed as that the α-helical content increases and the structure loosens. The microenvironment of amino acid residue in α-amylase is changed that the hydrophobicity decreases and the polarity increases with Cu 2+ exposure. Isothermal titration calorimetry results show that Van der Waals force and hydrogen bond exist in the interaction between Cu 2+ and α-amylase. Results from this research would favor the development of advanced process for the biological treatment of sludge containing heavy metals.

Effect of anaerobic digestion and liming on plant availability of phosphorus in iron- and aluminium-precipitated sewage sludge from primary wastewater treatment plants.

PubMed

Alvarenga, Emilio; Øgaard, Anne Falk; Vråle, Lasse

2017-04-01

More efficient plant utilisation of the phosphorus (P) in sewage sludge is required because rock phosphate is a limited resource. To meet environmental legislation thresholds for P removal from wastewater (WW), primary treatment with iron (Fe) or aluminium (Al) coagulants is effective. There is also a growing trend for WW treatment plants (WWTPs) to be coupled to a biogas process, in order to co-generate energy. The sludge produced, when stabilised, is used as a soil amendment in many countries. This study examined the effects of anaerobic digestion (AD), with or without liming as a post-treatment, on P release from Fe- and Al-precipitated sludges originating from primary WWTPs. Plant uptake of P from Fe- and Al-precipitated sludge after lime treatment but without AD was also compared. Chemical characterisation with sequential extraction of P and a greenhouse experiment with barley (Hordeum vulgare) were performed to assess the treatment effects on plant-available P. Liming increased the P-labile fraction in all cases. Plant P uptake increased from 18.5 mg pot -1 to 53 mg P pot -1 with liming of Fe-precipitated sludge and to 35 mg P pot -1 with liming of the digestate, while it increased from 18.7 mg pot -1 to 39 and 29 mg P pot -1 for the Al-precipitated substrate and digestate, respectively. Thus, liming of untreated Fe-precipitated sludge and its digestate resulted in higher P uptake than liming its Al-precipitated counterparts. AD had a negative impact on P mobility for both sludges.

Energy saving system with high effluent quality for municipal sewage treatment by UASB-DHS.

PubMed

Tanaka, H; Takahashi, M; Yoneyama, Y; Syutsubo, K; Kato, K; Nagano, A; Yamaguchi, T; Harada, H

2012-01-01

An up-flow anaerobic sludge blanket (UASB) - down-flow hanging sponge (DHS) was applied to Japanese municipal sewage treatment, and its treatability, energy consumption, and sludge production were evaluated. The designed sewage load was 50 m(3)/d. The sewage typically had a chemical oxygen demand (COD) of 402 mg/L, a suspended solids (SS) content of 167 mg/L, and a temperature of 17-29 °C. The UASB and DHS exhibited theoretical hydraulic retention times of 9.7 and 2.5 h, respectively. The entire system was operated without temperature control. Operation was started with mesophilic anaerobic digested sludge for the UASB and various sponge media for the DHS. Continuous operational data suggest that although the cellulose decomposition and methanogenic process in the UASB are temperature sensitive, stable operation can be obtained by maintaining a satisfactory sludge volume index and sludge concentration. For the DHS, the cube-type medium G3-2 offers superior filling rates, biological preservation and operational execution. The SS derived from the DHS contaminated the effluent but could be removed by optional sand filtration. A comparison with conventional activated sludge (CAS) treatment confirmed that this system is adequate for municipal sewage treatment, with an estimated energy requirement and excess sludge production approximately 75 and 85% less than those of CAS, respectively.

Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.

PubMed

Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

2014-12-01

Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oxidation Ditch Technology for Upgrading Army Sewage Treatment Facilities.

DTIC Science & Technology

1983-08-01

expensive and unreliable anaerobic digestion . Because of these advantages, oxidation ditch technology should be considered when planning wastewater...eliminates the need for further sludge treatment (e.g., anaerobic digestion can be eliminated). Does not need primary clarifier. Few moving parts in...four Army plants (see Chapter 2) use the anaerobic digestion process for sludge treatment. There are often problems in operating these digestors, and

Energy potential and alternative usages of biogas and sludge from UASB reactors: case study of the Laboreaux wastewater treatment plant.

PubMed

Rosa, A P; Conesa, J A; Fullana, A; Melo, G C B; Borges, J M; Chernicharo, C A L

2016-01-01

This work assessed the energy potential and alternative usages of biogas and sludge generated in upflow anaerobic sludge blanket reactors at the Laboreaux sewage treatment plant (STP), Brazil. Two scenarios were considered: (i) priority use of biogas for the thermal drying of dehydrated sludge and the use of the excess biogas for electricity generation in an ICE (internal combustion engine); and (ii) priority use of biogas for electricity generation and the use of the heat of the engine exhaust gases for the thermal drying of the sludge. Scenario 1 showed that the electricity generated is able to supply 22.2% of the STP power demand, but the thermal drying process enables a greater reduction or even elimination of the final volume of sludge to be disposed. In Scenario 2, the electricity generated is able to supply 57.6% of the STP power demand; however, the heat in the exhaust gases is not enough to dry the total amount of dehydrated sludge.

Operational Control Procedures for the Activated Sludge Process, Part III-B: Calculation Procedures for Step-Feed Process Responses and Addendum No. 1.

ERIC Educational Resources Information Center

West, Alfred W.

This is the third in a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. This document deals with the calculation procedures associated with a step-feed process. Illustrations and examples are included to…

Use of Alum for Odor Reduction in Sludge and Biosolids from Different Wastewater Treatment Processes.

PubMed

Gruchlik, Yolanta; Fouché, Lise; Joll, Cynthia A; Heitz, Anna

2017-12-01

  Applicability of alum addition to wastewater sludge and biosolids produced from different treatment processes was evaluated as a means of odor reduction. Four water resource recovery facilities (WRRFs) were chosen for this study: two used mesophilic anaerobic digestion and two used oxidation ditch processes. The experiments were conducted on a laboratory scale and in all cases the alum was added prior to dewatering. This is the first report of the application of alum for odor reduction in oxidation ditch processes. Alum addition was effective in reducing odors in anaerobically digested biosolids. Addition of 4% alum to anaerobically digested liquid biosolids prior to dewatering resulted in a 60% reduction in the peak odor concentration in the laboratory dewatered cake, relative to the control sample. Alum addition did not reduce odors in dewatered sludge from oxidation ditch processes.

The Influence of Ultrasonic Cavitation on the Formation of Fe-Rich Intermetallics in A383 Alloy

NASA Astrophysics Data System (ADS)

Xuan, Yang; Liu, Tao; Nastac, Laurentiu; Brewer, Luke; Levin, Ilya; Arvikar, Vish

2018-06-01

The effect of ultrasonic treatment (UST) on the formation of Fe-rich intermetallics (including sludge) in the A383 alloy is investigated for different processing temperatures in the present study. Differential scanning calorimetry is used to analyze the precipitation temperature of the sludge phase. The results revealed that the sludge will precipitate at a temperature above that of the Al matrix and the precipitation temperature decreases with an increasing cooling rate. UST cavitation applied at different temperatures (600 °C to 750 °C) during the solidification process breaks the sludge into small island-like pieces. However, the aggregation trend of the sludge is not changed. Sludge with small size and uniform distribution is obtained when UST is applied at 600 °C, which is lower than the precipitation temperature of the sludge. At the highest temperature (850 °C), the application of UST has no effect on the formation of either sludge or α-Fe intermetallics. At 750 °C, UST promotes the formation of the sludge when applied at 750 °C.

Disintegration impact on sludge digestion process.

PubMed

Dauknys, Regimantas; Rimeika, Mindaugas; Jankeliūnaitė, Eglė; Mažeikienė, Aušra

2016-11-01

The anaerobic sludge digestion is a widely used method for sludge stabilization in wastewater treatment plant. This process can be improved by applying the sludge disintegration methods. As the sludge disintegration is not investigated enough, an analysis of how the application of thermal hydrolysis affects the sludge digestion process based on full-scale data was conducted. The results showed that the maximum volatile suspended solids (VSS) destruction reached the value of 65% independently on the application of thermal hydrolysis. The average VSS destruction increased by 14% when thermal hydrolysis was applied. In order to have the maximum VSS reduction and biogas production, it is recommended to keep the maximum defined VSS loading of 5.7 kg VSS/m(3)/d when the thermal hydrolysis is applied and to keep the VSS loading between 2.1-2.4 kg VSS/m(3)/d when the disintegration of sludge is not applied. The application of thermal hydrolysis leads to an approximately 2.5 times higher VSS loading maintenance comparing VSS loading without the disintegration; therefore, digesters with 1.8 times smaller volume is required.

Reduction in greenhouse gas emissions from sludge biodrying instead of heat drying combined with mono-incineration in China.

PubMed

Liu, Hong-Tao; Wang, Yan-Wen; Liu, Xiao-Jie; Gao, Ding; Zheng, Guo-di; Lei, Mei; Guo, Guang-Hui; Zheng, Hai-Xia; Kong, Xiang-Juan

2017-02-01

Sludge is an important source of greenhouse gas (GHG) emissions, both in the form of direct process emissions and as a result of indirect carbon-derived energy consumption during processing. In this study, the carbon budgets of two sludge disposal processes at two well-known sludge disposal sites in China (for biodrying and heat-drying pretreatments, both followed by mono-incineration) were quantified and compared. Total GHG emissions from heat drying combined with mono-incineration was 0.1731 tCO 2 e t -1 , while 0.0882 tCO 2 e t -1 was emitted from biodrying combined with mono-incineration. Based on these findings, a significant reduction (approximately 50%) in total GHG emissions was obtained by biodrying instead of heat drying prior to sludge incineration. Sludge treatment results in direct and indirect greenhouse gas (GHG) emissions. Moisture reduction followed by incineration is commonly used to dispose of sludge in China; however, few studies have compared the effects of different drying pretreatment options on GHG emissions during such processes. Therefore, in this study, the carbon budgets of sludge incineration were analyzed and compared following different pretreatment drying technologies (biodrying and heat drying). The results indicate that biodrying combined with incineration generated approximately half of the GHG emissions compared to heat drying followed by incineration. Accordingly, biodrying may represent a more environment-friendly sludge pretreatment prior to incineration.

Methods for Converter Sludge Dehydration Intensification

NASA Astrophysics Data System (ADS)

Vakhromeev, M. I.; Moreva, Y. A.; Starkova, L. G.

2017-11-01

The article considers the intensification methods for converter sludge dehydration exemplified by the sludges of the Oxygen Converter Workshop (OCW) of the Open Joint-Stock Company “Magnitogorsk Iron and Steel Works” (MMK, OJSC), one of the largest metallurgical companies in the Southern Urals. Converter sludges can contain up to 45-70% of ferrum [21] which is interesting in terms of their use as an addition to a sinter-feed mixture. Sludge intensifies the sintering process. It positively influences pelletizing and fusion mixture melting dynamics at sintering. Over the period of the converter sludge dehydration complex operation at the OCW, MMK, OJSC, it was revealed that processing results in obtaining of high humidity sludge. It causes sludge freezing during the winter period, thus, its transportation involves extra costs for sludge warming up. To resolve the above-mentioned problem, the following works were performed in 2016: - experimental studies of how the application of the low-molecular anionic flocculate “SEURVEY” FL-3 influences sludge humidity reduction. - experimental studies of how the filtering press process operation parameters influence sludge humidity reduction. The new flocculate application didn't lower the dehydrated sludge humidity (the objective was the humidity of not more than 15%). Basing upon the conducted research results, we can make a conclusion that putting into operation the sewage water reactant treatment technology with the use of “SEURVEY”, FL-3 (H-10) is not recommended. The research of the influence the filtering press process parameters have on the dehydration process intensification demonstrated that reaching of the obtained residue humidity value lower than 15% is possible under the reduction of the filtering press chamber depths to 30 mm and with the application of additional operation “Residue drying” with compressed air. This way of the sludge dehydration problem resolving at filtering presses of the converter sludge dehydration complex of the OCW, MMK, OJSC, can be recommended for application.

Investigation of bacterial community in activated sludge with an anaerobic side-stream reactor (ASSR) to decrease the generation of excess sludge.

PubMed

Kim, Young Mo; Chon, Dong-Hyun; Kim, Hee-Sik; Park, Chul

2012-09-01

The goal of this study was to investigate the bacterial community in activated sludge with an anaerobic side-stream reactor (ASSR), a process permitting significant decrease in sludge production during wastewater treatment. The study operated five activated sludge systems with different sludge treatment schemes serving as various controls for the activated sludge with ASSR. Bacterial communities were analyzed by denaturing gradient gel electrophoresis (DGGE), sequencing and construction of phylogenetic relationships of the identified bacteria. The DGGE data showed that activated sludge incorporating ASSR contained higher diversity of bacteria, resulting from long solids retention time and recirculation of sludge under aerobic and anaerobic conditions. The similarity of DGGE profiles between ASSR and separate anaerobic digester (control) was high indicating that ASSR is primarily related to conventional anaerobic digesters. Nevertheless, there was also unique bacteria community appearing in ASSR. Interestingly, sludge in the main system and in ASSR showed considerably different bacterial composition indicating that ASSR allowed enriching its own bacterial community different than that from the aeration basin, although two reactors were connected via sludge recirculation. In activated sludge with ASSR, sequences represented by predominant DGGE bands were affiliated with Proteobacteria. The remaining groups were composed of Spirochaetes, Clostridiales, Chloroflexi, and Actinobacteria. Their putative role in the activated sludge with ASSR is also discussed in this study. Copyright © 2012 Elsevier Ltd. All rights reserved.

Microbial Community Composition in a Simultaneous Nitrification and Denitrification Bioreactor for Domestic Wastewater Treatment

NASA Astrophysics Data System (ADS)

Chen, Chen; Ouyang, Wukun; Huang, Shan; Peng, Xiaochun

2018-01-01

Traditional domestic wastewater treatments rely on aerobic processes followed by anaerobic processes. The aerobic step in which ammonium and organic carbon are oxidized, calls for large oxygen input, while the anaerobic process often requires extra carbon input. The challenge of synchronizing both processes is to maintain an active nitrifiers sludge under low dissolved oxygen (DO) condition. In this study, a membrane bioreactor was established and operated stable with low DO of 0.1-0.4 mg L-1. Chemical indicators were determined daily, and bacterial community was checked by qPCR and 16S rDNA sequencing every month. After 2 months incubation, the bioreactor reached to a stable removal rate of total nitrogen around 50% and total organic carbon around 90% with the retaining time of 12 h. The sludge showed enrichment of low DO nitrifiers (Nitrosomonadaceae, Chitinophagaceae, and Nitrospiraceae) which were different from sludge in other regular wastewater treatment plants with aerobic and anaerobic cycles.

40 CFR Appendix B to Part 503 - Pathogen Treatment Processes

Code of Federal Regulations, 2011 CFR

2011-07-01

... 55 to 60 degrees Celsius. 5. Beta ray irradiation—Sewage sludge is irradiated with beta rays from an... irradiation—Sewage sludge is irradiated with gamma rays from certain isotopes, such as 60 Cobalt and 137...

40 CFR Appendix B to Part 503 - Pathogen Treatment Processes

Code of Federal Regulations, 2013 CFR

2013-07-01

... 55 to 60 degrees Celsius. 5. Beta ray irradiation—Sewage sludge is irradiated with beta rays from an... irradiation—Sewage sludge is irradiated with gamma rays from certain isotopes, such as 60 Cobalt and 137...

40 CFR Appendix B to Part 503 - Pathogen Treatment Processes

Code of Federal Regulations, 2014 CFR

2014-07-01

... 55 to 60 degrees Celsius. 5. Beta ray irradiation—Sewage sludge is irradiated with beta rays from an... irradiation—Sewage sludge is irradiated with gamma rays from certain isotopes, such as 60 Cobalt and 137...

40 CFR Appendix B to Part 503 - Pathogen Treatment Processes

Code of Federal Regulations, 2010 CFR

2010-07-01

... 55 to 60 degrees Celsius. 5. Beta ray irradiation—Sewage sludge is irradiated with beta rays from an... irradiation—Sewage sludge is irradiated with gamma rays from certain isotopes, such as 60 Cobalt and 137...

40 CFR Appendix B to Part 503 - Pathogen Treatment Processes

Code of Federal Regulations, 2012 CFR

2012-07-01

... 55 to 60 degrees Celsius. 5. Beta ray irradiation—Sewage sludge is irradiated with beta rays from an... irradiation—Sewage sludge is irradiated with gamma rays from certain isotopes, such as 60 Cobalt and 137...

A novel conversion of the groundwater treatment sludge to magnetic particles for the adsorption of methylene blue.

PubMed

Zhu, Suiyi; Fang, Shuai; Huo, Mingxin; Yu, Yang; Chen, Yu; Yang, Xia; Geng, Zhi; Wang, Yi; Bian, Dejun; Huo, Hongliang

2015-07-15

Iron sludge, produced from filtration and backwash of groundwater treatment plant, has long been considered as a waste for landfill. In this study, iron sludge was reused to synthesize Fe3O4 magnetic particles (MPs) by using a novel solvothermal process. Iron sludge contained abundant amounts of silicon, iron, and aluminum and did not exhibit magnetic properties. After treatment for 4h, the amorphous Fe in iron sludge was transformed into magnetite Fe3O4, which could be easily separated from aqueous solution with a magnet. The prepared particles demonstrated the intrinsic properties of soft magnetic materials and could aggregate into a size of 1 μm. MPs treated for 10h exhibited excellent magnetic properties and a saturation magnetization value of 9 emu/g. The obtained particles presented the optimal adsorption of methylene blue under mild conditions, and the maximum adsorption capacity was 99.4 mg/g, which was higher than that of granular active carbon. The simple solvothermal method can be used to prepare Fe3O4 MPs from iron sludge, and the products could be applied to treatment of dyeing wastewater. Copyright © 2015. Published by Elsevier B.V.

Practical experience with full-scale structured sheet media (SSM) integrated fixed-film activated sludge (IFAS) systems for nitrification.

PubMed

Li, Hua; Zhu, Jia; Flamming, James J; O'Connell, Jack; Shrader, Michael

2015-01-01

Many wastewater treatment plants in the USA, which were originally designed as secondary treatment systems with no or partial nitrification requirements, are facing increased flows, loads, and more stringent ammonia discharge limits. Plant expansion is often not cost-effective due to either high construction costs or lack of land. Under these circumstances, integrated fixed-film activated sludge (IFAS) systems using both suspended growth and biofilms that grow attached to a fixed plastic structured sheet media are found to be a viable solution for solving the challenges. Multiple plants have been retrofitted with such IFAS systems in the past few years. The system has proven to be efficient and reliable in achieving not only consistent nitrification, but also enhanced bio-chemical oxygen demand removal and sludge settling characteristics. This paper presents long-term practical experiences with the IFAS system design, operation and maintenance, and performance for three full-scale plants with distinct processes; that is, a trickling filter/solids contact process, a conventional plug flow activated sludge process and an extended aeration process.

Recent developments in the Sandia Laboratories' sewage sludge irradiation program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sivinski, H.D.; Brandon, J.R.; Morris, M.E.

1977-11-01

Pathogen reduction studies have shown that a 1 Mrad treatment (or less at elevated temperatures) is very effective in eliminating pathogenic bacteria and viable parasite ova in liquid sludges. Heat is effective in reducing levels not only of pathogenic bacteria and Ascaris ova, but viruses as well. Ammonia has been shown to be virucidal to poliovirus and several other enteric viruses. Sludge processing costs are seen to be marginally competitive with heat treatment for liquid sludges and relatively economical for composted or dried sludges. Physical/chemical effects studies have shown that the effects of irradiation of sludges on dewatering properties aremore » not significant when compared to polymers, nor is the combined effect synergistic. Dried, irradiated undigested sludge has been shown to be of significant nutritional value when used as a feed supplement for sheep and cattle, as well as in agronomic uses. No significant harmful effects have been demonstrated in the feeding program thus far. Product enhancement studies are currently under way, including schemes for removing nitrogen from effluent streams for addition as ammonium salts to sludges.« less

[Evaluating the Significance of Odor Gas Released During the Directly Drying Process of Sludge: Based on the Multi-index Integrated Assessment Method].

PubMed

Ding, Wen-jie; Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Li, Lin; Liu, Jun-xin

2016-02-15

Co-processing of sewage sludge using the cement kiln can realize sludge harmless treatment, quantity reduction, stabilization and reutilization. The moisture content should be reduced to below 30% to meet the requirement of combustion. Thermal drying is an effective way for sludge desiccation. Odors and volatile organic compounds are generated and released during the sludge drying process, which could lead to odor pollution. The main odor pollutants were selected by the multi-index integrated assessment method. The concentration, olfactory threshold, threshold limit value, smell security level and saturated vapor pressure were considered as indexes based on the related regulations in China and foreign countries. Taking the pollution potential as the evaluation target, and the risk index and odor emission intensity as evaluation indexes, the odor pollution potential rated evaluation model of the pollutants was built according to the Weber-Fechner law. The aim of the present study is to form the rating evaluation method of odor potential pollution capacity suitable for the directly drying process of sludge.

Evaluation of advanced wastewater treatment systems for water reuse in the era of advanced wastewater treatment

NASA Astrophysics Data System (ADS)

Kon, Hisao; Watanabe, Masahiro

This study focuses on effluent COD concentration from wastewater treatment in regards to the reduction of pathogenic bacteria and trace substances in public waters. The main types of secondary wastewater treatment were conventional activated sludge processes. Recently, however, advance wastewater treatment processes have been developed aimed at the removal of nitrogen and phosphorus, and the effluent quality of these processes was analyzed in this study. Treatment processes for water reclamation that make effluent to meet the target water quality for reuse purposes were selected and also optimum design parameters for these processes were proposed. It was found that the treatment cost to water reclamation was greatly affected by the effluent COD of the secondary treatment. It is important to maintain low COD concentration in the secondary treated effluent. Therefore, it is considered that adequate cost benefits would be obtained by achieving target COD quality through shifting from a conventional activated sludge process to an advanced treatment process.

Sewage sludge drying process integration with a waste-to-energy power plant.

PubMed

Bianchini, A; Bonfiglioli, L; Pellegrini, M; Saccani, C

2015-08-01

Dewatered sewage sludge from Waste Water Treatment Plants (WWTPs) is encountering increasing problems associated with its disposal. Several solutions have been proposed in the last years regarding energy and materials recovery from sewage sludge. Current technological solutions have relevant limits as dewatered sewage sludge is characterized by a high water content (70-75% by weight), even if mechanically treated. A Refuse Derived Fuel (RDF) with good thermal characteristics in terms of Lower Heating Value (LHV) can be obtained if dewatered sludge is further processed, for example by a thermal drying stage. Sewage sludge thermal drying is not sustainable if the power is fed by primary energy sources, but can be appealing if waste heat, recovered from other processes, is used. A suitable integration can be realized between a WWTP and a waste-to-energy (WTE) power plant through the recovery of WTE waste heat as energy source for sewage sludge drying. In this paper, the properties of sewage sludge from three different WWTPs are studied. On the basis of the results obtained, a facility for the integration of sewage sludge drying within a WTE power plant is developed. Furthermore, energy and mass balances are set up in order to evaluate the benefits brought by the described integration. Copyright © 2015 Elsevier Ltd. All rights reserved.

The manufacture and use of sludge test materials for R and D purposes in the treatment and processing of magnox based sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackburn, D.R.; Thompson, E.J.

2013-07-01

Among the Intermediate Level Waste materials in store and awaiting treatment and processing in the UK are quantities of magnesium hydroxide sludge. This sludge is a product of radioactive Magnox Swarf which arose from the de-canning of used magnox fuel element rods. As the Swarf was stored underwater, a corrosion reaction occurred over the course of time between the magnox and the water resulting in a magnesium hydroxide based sludge. The differing conditions and materials present in the various storage areas means that the sludge can range in consistency from that of a slurry through to a thick clay. Sludgemore » test materials are required to underpin and validate the research and development equipment and processes that are to be used to treat the waste material. Necessary restrictions imposed on the sampling and testing of the radioactive waste means that the available data on the properties and behaviour of the sludge is limited. The raw materials used to create the sludge test materials are based upon magnesium hydroxide so that as far as possible the chemical behaviour will be similar to that of the waste material. The most representative sludge test material is manufactured by the corrosion of non-radioactive magnox or magnesium. However, time constraints make it impractical to supply this material in sufficient quantities for full scale validation trials. An alternative is to use sludge manufactured from commercially available magnesium hydroxide. The particle shape of commercially available materials differs from corrosion product magnesium hydroxide which means that properties such as the rheological behaviour cannot be replicated. Nevertheless, valuable trial data can be obtained, giving a greater degree of confidence in the waste treatment process than would be possible if only the more representative but less available corrosion product materials were to be used. Key test material parameters used in the trials have been identified as the particle size distribution and the sludge thickness (measured as yield shear strength). Other properties including cohesion, adhesion and rheological behaviour are also considered. The use of different mixers for sludge manufacture has the potential to affect the behavioural properties and a brief description of each of these mixers is included. The scale of mixing has been found to make a significant difference to the ageing. A chemical impurity in the commercially available materials has been successfully exploited, so that sludge mixed at comparatively low yield shear strengths can thicken into the consistency of clay. This aids manufacture and allows large quantities of thick material to be produced relatively easily. (authors)« less

Lifecycle analysis of renewable natural gas and hydrocarbon fuels from wastewater treatment plants’ sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Uisung; Han, Jeongwoo; Urgun Demirtas, Meltem

Wastewater treatment plants (WWTPs) produce sludge as a byproduct when they treat wastewater. In the United States, over 8 million dry tons of sludge are produced annually just from publicly owned WWTPs. Sludge is commonly treated in anaerobic digesters, which generate biogas; the biogas is then largely flared to reduce emissions of methane, a potent greenhouse gas. Because sludge is quite homogeneous and has a high energy content, it is a good potential feedstock for other conversion processes that make biofuels, bioproducts, and power. For example, biogas from anaerobic digesters can be used to generate renewable natural gas (RNG), whichmore » can be further processed to produce compressed natural gas (CNG) and liquefied natural gas (LNG). Sludge can be directly converted into hydrocarbon liquid fuels via thermochemical processes such as hydrothermal liquefaction (HTL). Currently, the environmental impacts of converting sludge into energy are largely unknown, and only a few studies have focused on the environmental impacts of RNG produced from existing anaerobic digesters. As biofuels from sludge generate high interest, however, existing anaerobic digesters could be upgraded to technology with more economic potential and more environmental benefits. The environmental impacts of using a different anaerobic digestion (AD) technology to convert sludge into energy have yet to be analyzed. In addition, no studies are available about the direct conversion of sludge into liquid fuels. In order to estimate the energy consumption and greenhouse gas (GHG) emissions impacts of these alternative pathways (sludge-to-RNG and sludge-to-liquid), this study performed a lifecycle analysis (LCA) using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. The energy uses and GHG emissions associated with the RNG and hydrocarbon liquid are analyzed relative to the current typical sludge management case, which consists of a single-stage mesophilic digester with biogas flaring. Along with the alternative HTL process, four types of AD technologies with fuel production—single-stage mesophilic, mesophilic 2-stage, single-stage mesophilic with thermohydrolysis treatment, and mesophilicmesophilic acid/gas phase—are studied. Results show that the sludge-to-CNG pathway via AD and the sludge-to-liquid pathway via HTL reduce GHG emissions consumptions significantly. When we compare the GHG emissions of the alternative fuel production pathways to that of the counterfactual case in terms of the amount of sludge treated, reductions in GHG emissions are 39%–80% and 87% for alternative AD and HTL, respectively. Compared to petroleum gasoline and diesel GHG emission results in terms of MJ, the renewable CNG production pathway via AD and the renewable diesel production pathway via HTL reduce GHG emissions by 193% and 46%, respectively. These large reductions are mainly due to GHG credits from avoiding GHGs under the counterfactual scenario, and/or fertilizer displacement credits. Similarly, reductions in fossil fuel use for sludge-based fuels are huge. However, well-defined counterfactual scenarios are needed because the results of the study depend on the counterfactual scenario, which might vary over time.« less

Occurrence, distribution, and potential affecting factors of organophosphate flame retardants in sewage sludge of wastewater treatment plants in Henan Province, Central China.

PubMed

Pang, Long; Yuan, Yiting; He, Han; Liang, Kang; Zhang, Hongzhong; Zhao, Jihong

2016-06-01

Organophosphate esters (OPEs) are widely used as flame retardants. In this study, the occurrence and distribution of six OPEs were investigated in sewage sludge from 24 wastewater treatment plants (WWTPs) in 18 cities of Henan province, Central China. The results indicated that all target OPEs were detected in the sludge samples with the detection rate of 95.8%, except tris(dichloropropyl)phosphate (TDCP). The total concentration of the six OPEs ranged from 38.6 to 508 μg kg(-1). Tris(2-chloroethyl)phosphate (TCEP), tris(2-butoxyethyl)phosphate (TBEP), and tris(2-chloroiso-propyl)phosphate (TCPP) were found to be predominant, with concentrations ranging from 2.50 to 203, 1.60 to 383, and 6.70-161 μg kg(-1), respectively. The potential factors affecting OPE levels in sewage sludge, such as wastewater source, sludge characteristics, operational conditions, treatment techniques, and total organic carbon (TOC) of sludge in WWTPs were investigated. The results indicated that the total concentration of OPEs in sewage sludge has no significant relationship with the individual parameters (p > 0.05). However, significant correlations were found between triphenyl phosphate (TPhP) level and treatment capacity (R = 0.484, p < 0.05), processing volume (R = 0.495, p < 0.05), and serving population (R = 0.591, p < 0.05). Furthermore, the relationship between treatment techniques and the total concentration of OPEs in sewage sludge was also investigated in this study, and the results illustrated that the levels of OPEs in sludge were independent of the solid retention time (SRT). Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphorous removal from aqueous solution can be enhanced through the calcination of lime sludge.

PubMed

Bal Krishna, K C; Niaz, Mohamed R; Sarker, Dipok C; Jansen, Troy

2017-09-15

Water treatment plants generate an enormous amount of the sludge which is normally treated as waste. In the recent past, many investigations have been focused on developing an economical adsorbent using water treatment sludge to remove phosphorous (P) from aqueous solutions. However, the great extents of the studies have been limited in the use of alum- and iron-based sludges. This study, therefore, investigated the P removal performance of the calcined lime sludge. Calcined lime sludge at 700 °C significantly enhanced the P removal efficiency whereas marginal improvement was noted when the sludge calcined at 400 °C was tested. With increase P removal efficiency, final pH values of the solution also significantly increased. P removal efficiency of the calcined sludge decreased with increasing the initial P concentrations. However, the removal efficiency could be improved by increasing the weight of the sludge. Further analysis demonstrated that P removal trend followed both pseudo-second order and diffusion-chemisorption kinetics signifying the P removal is potentially due to a multi-mechanistic reaction in which, the process is controlled by intra-particle diffusion followed by chemisorptions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occurrence and fate of acrylamide in water-recycling systems and sludge in aggregate industries.

PubMed

Junqua, Guillaume; Spinelli, Sylvie; Gonzalez, Catherine

2015-05-01

Acrylamide is a hazardous substance having irritant and toxic properties as well as carcinogen, mutagen, and impaired fertility possible effects. Acrylamide might be found in the environment as a consequence of the use of polyacrylamides (PAMs) widely added as a flocculant for water treatment. Acrylamide is a monomer used to produce polyacrylamide (PAM) polymers. This reaction of polymerization can be incomplete, and acrylamide molecules can be present as traces in the commercial polymer. Thus, the use of PAMs may generate a release of acrylamide in the environment. In aggregate industries, PAM is widely involved in recycling process and water reuse (aggregate washing). Indeed, these industries consume large quantities of water. Thus, European and French regulations have favored loops of recycling of water in order to reduce water withdrawals. The main goal of this article is to study the occurrence and fate of acrylamide in water-recycling process as well as in the sludge produced by the flocculation treatment process in aggregate production plants. Moreover, to strengthen the relevance of this article, the objective is also to demonstrate if the recycling system leads to an accumulation effect in waters and sludge and if free acrylamide could be released by sludge during their storage. To reach this objective, water sampled at different steps of recycling water process has been analyzed as well as different sludge corresponding to various storage times. The obtained results reveal no accumulation effect in the water of the water-recycling system nor in the sludge.

Electricity generation from bio-treatment of sewage sludge with microbial fuel cell.

PubMed

Jiang, Junqiu; Zhao, Qingliang; Zhang, Jinna; Zhang, Guodong; Lee, Duu-Jong

2009-12-01

A two-chambered microbial fuel cell (MFC) with potassium ferricyanide as its electron acceptor was utilized to degrade excess sewage sludge and to generate electricity. Stable electrical power was produced continuously during operation for 250 h. Total chemical oxygen demand (TCOD) of sludge was reduced by 46.4% when an initial TCOD was 10,850 mg/l. The MFC power output did not significantly depend on process parameters such as substrate concentration, cathode catholyte concentration, and anodic pH. However, the MFC produced power was in close correlation with the soluble chemical oxygen demand (SCOD) of sludge. Furthermore, ultrasonic pretreatment of sludge accelerated organic matter dissolution and, hence, TCOD removal rate in the MFC was increased, but power output was insignificantly enhanced. This study demonstrates that this MFC can generate electricity from sewage sludge over a wide range of process parameters.

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry.

PubMed

Buyukkamaci, Nurdan; Koken, Emre

2010-11-15

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000m(3)/day range with 1000m(3)/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents. Copyright © 2010 Elsevier B.V. All rights reserved.

Combined mesophilic anaerobic and thermophilic aerobic digestion process for high-strength food wastewater to increase removal efficiency and reduce sludge discharge.

PubMed

Jang, H M; Park, S K; Ha, J H; Park, J M

2014-01-01

In this study, a process that combines the mesophilic anaerobic digestion (MAD) process with thermophilic aerobic digestion (TAD) for high-strength food wastewater (FWW) treatment was developed to examine the removal of organic matter and methane production. All effluent discharged from the MAD process was separated into solid and liquid portions. The liquid part was discarded and the sludge part was passed to the TAD process for further degradation. Then, the digested sludge from the TAD process was recycled back to the MAD unit to achieve low sludge discharge from the combined process. The reactor combination was operated in two phases: during Phase I, 40 d of total hydraulic retention time (HRT) was applied; during Phase II, 20 d was applied. HRT of the TAD process was fixed at 5 d. For a comparison, a control process (single-stage MAD) was operated with the same HRTs of the combined process. Our results indicated that the combined process showed over 90% total solids, volatile solids and chemical oxygen demand removal efficiencies. In addition, the combined process showed a significantly higher methane production rate than that of the control process. Consequently, the experimental data demonstrated that the combined MAD-TAD process was successfully employed for high-strength FWW treatment with highly efficient organic matter reduction and methane production.

The occurrence and significance to animal health of salmonellas in sewage and sewage sludges.

PubMed Central

Jones, P. W.; Rennison, L. M.; Lewin, V. H.; Redhead, D. L.

1980-01-01

A total of 882 samples of settled sewage, sewage sludges and final effluents from eight sewage treatment plants were examined for the presence of salmonellas. Of these samples 68% were positive, isolations being made most frequently from settled sewage (85%), raw sludge (87%) and anaerobically digested sludge (96%). Fewer isolations were made from final effluent (24%) and processed sludges (58%). Samples usually contained less than 200 salmonellas/100 ml and arguments are presented that such concentrations should not lead to disease in animals if suitable grazing restrictions are followed. PMID:6985928

Two step esterification-transesterification process of wet greasy sewage sludge for biodiesel production.

PubMed

Urrutia, C; Sangaletti-Gerhard, N; Cea, M; Suazo, A; Aliberti, A; Navia, R

2016-01-01

Sewage sludge generated in municipal wastewater treatment plants was used as a feedstock for biodiesel production via esterification/transesterification in a two-step process. In the first esterification step, greasy and secondary sludge were tested using acid and enzymatic catalysts. The results indicate that both catalysts performed the esterification of free fatty acids (FFA) simultaneously with the transesterification of triacylglycerols (TAG). Acid catalyst demonstrated better performance in FFA esterification compared to TAG transesterification, while enzymatic catalyst showed the ability to first hydrolyze TAG in FFA, which were esterified to methyl esters. In addition, FAME concentration using greasy sludge were higher (63.9% and 58.7%), compared with those of secondary sludge (11% and 16%), using acid and enzymatic catalysts, respectively. Therefore, only greasy sludge was used in the second step of alkaline transesterification. The alkaline transesterification of the previously esterified greasy sludge reached a maximum FAME concentration of 65.4% when using acid catalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

Occurrence and removal of endocrine-disrupting chemicals in wastewater treatment plants in the Three Gorges Reservoir area, Chongqing, China.

PubMed

Ye, Xin; Guo, Xuesong; Cui, Xing; Zhang, Xian; Zhang, Han; Wang, M K; Qiu, Ling; Chen, Shaohua

2012-08-01

Concentrations of six endocrine-disrupting compounds (EDCs), bisphenol A (BPA), estrone (E(1)), 17β-estradiol (E(2)), estriol (E(3)), 17α-ethynylestradiol (EE(2)) and diethylstilbestrol (DES), were assessed in influents, effluents and excess sludge in ten municipal wastewater treatment plants (WWTPs) in the Three Gorges Reservoir (TGR) area, Chongqing, China. Three types of activated sludge treatment processes, oxidation ditch (OD), reversed anaerobic-anoxic-oxic (rA(2)/O) technology and sequential batch reactor (SBR), were used in the surveyed WWTPs. These WWTPs were all combined landfill leachate-sewage treatment plants. All analytes were extracted by solid-phase extraction (SPE) in the dissolved phase and by accelerated solvent-based extraction (ASE) in sludge. Gas chromatography-mass spectrometry (GC-MS) was employed for the analysis of EDCs. Among these EDCs, BPA was the most frequently detected and abundant compound (100.0-10566.7 ng L(-1), 15.5-1210.7 ng L(-1) and 85.0-2470.4 ng g(-1) with respect to the influents, effluents and excess sludge samples). The greatest levels of steroidal estrogens in municipal influents were observed in E(3) which were all >100 ng L(-1), followed by E(1) (42.2-110.7 ng L(-1)) and E(2) (7.4-32.7 ng L(-1)), and in the effluents and sludge were E(1) > E(3) > E(2) which were all <31 ng L(-1) and 105 ng g(-1), respectively. Regarding synthetic estrogens, EE(2) was frequently detected in the influents, occurring below 50 ng L(-1), while DES was not detected at all. A high correlation coefficient was observed between the leachate-sludge ratio and concentrations of influent EDCs, and it was statistically significant (i.e., R > 0.65, P < 0.05), but removal efficiency of the EDCs did not show significant differences with OD, rA(2)/O and SBR processes. Furthermore, modification of treatment technology as well as operational parameters, such as hydraulic retention time (HRT), sludge retention time (SRT) and disinfection process (DP), were recommended to further eliminate the residual EDCs.

Benchmarking of municipal waste water treatment plants (an Austrian project).

PubMed

Lindtner, S; Kroiss, H; Nowak, O

2004-01-01

An Austrian research project focused on the development of process indicators for treatment plants with different process and operation modes. The whole treatment scheme was subdivided into four processes, i.e. mechanical pretreatment (Process 1), mechanical-biological waste water treatment (Process 2), sludge thickening and stabilisation (Process 3) and further sludge treatment and disposal (Process 4). In order to get comparable process indicators it was necessary to subdivide the sample of 76 individual treatment plants all over Austria into five groups according to their mean organic load (COD) in the influent. The specific total yearly costs, the yearly operating costs and the yearly capital costs of the four processes have been related to the yearly average of the measured organic load expressed in COD (110 g COD/pe/d). The specific investment costs for the whole treatment plant and for Process 2 have been related to a calculated standard design capacity of the mechanical-biological part of the treatment plant expressed in COD. The capital costs of processes 1, 3 and 4 have been related to the design capacity of the treatment plant. For each group (related to the size of the plant) a benchmark band has been defined for the total yearly costs, the total yearly operational costs and the total yearly capital costs. For the operational costs of the Processes 1 to 4 one benchmark ([see symbol in text] per pe/year) has been defined for each group. In addition a theoretical cost reduction potential has been calculated. The cost efficiency in regard to water protection and some special sub-processes such as aeration and sludge dewatering has been analysed.

Pilot-scale comparison of thermophilic aerobic suspended carrier biofilm process and activated sludge process in pulp and paper mill effluent treatment.

PubMed

Suvilampi, J E; Rintala, J A

2004-01-01

Thermophilic aerobic treatment of settled pulp and paper mill effluent was studied under mill premises with two comparative pilot processes; suspended carrier biofilm process (SCBP) and activated sludge process (ASP). Full-scale mesophilic activated sludge process was a reference treatment. During the runs (61 days) hydraulic retention times (HRTs) were kept 13+/-5 h and 16+/-6 h for SCBP and ASP, respectively. Corresponding volumetric loadings rates (VLR) were 2.7+/-0.9 and 2.2+/-1.0 kg CODfilt m(-3)d(-1). Temperatures varied between 46 to 60 degrees C in both processes. Mesophilic ASP was operated with HRT of 36 h, corresponding VLR of 0.7 kg CODfilt m(-3)d(-1). Both SCBP and ASP achieved CODfilt (GF/A filtered) removals up to 85%, while the mesophilic ASP removal was 89+/-2%. NTU values were markedly higher (100-300) in thermophilic effluents than in mesophilic effluent (30). Effluent turbidity was highly dependent on temperature; in batch experiment mesophilic effluent sample had NTU values of 30 and 60 at 35 degrees C and 55 degrees C, respectively. As a conclusion, both thermophilic treatments gave high CODfilt removals, which were close to mesophilic process removal and were achieved with less than half of HRT.

Effect of dewatering and composting on helminth eggs removal from lagooning sludge under semi-arid climate.

PubMed

El Hayany, Bouchra; El Glaoui, Ghizlen El Mezouari; Rihanni, Mohammed; Ezzariai, Amine; El Faiz, Abdelouahed; El Gharous, Mohamed; Hafidi, Mohamed; El Fels, Loubna

2018-04-01

In this work, we assessed the drying and composting effectiveness of helminth eggs removal from sewage sludge of a lagoon wastewater treatment plant located in Chichaoua city. The composting was run after mixing sludge with green waste in different proportions: M1 (½ sludge + ½ green waste), M2 ([Formula: see text] sludge + [Formula: see text] green waste), and M3 ([Formula: see text] sludge + [Formula: see text] green waste) for 105 days. The analysis of the dewatered sewage sludge showed a load of 8-24 helminth eggs/g of fresh matter identified as Ascaris spp. eggs (5-19 eggs/g) followed by Toxocara spp. (0.2 to 2.4 eggs/g); Hookworm spp. and Capillaria spp. (0.4-1 egg/g); Trichuris spp., Taenia spp., and Shistosoma spp. (< 1 egg/g) in the untreated sludge. After 105 days of treatment by composting, we noted a total reduction of helminth eggs in the order of 97.5, 97.83, and 98.37% for mixtures M1, M2, and M3, respectively. The Ascaris spp. eggs were reduced by 98% for M1 and M3 treatments and by 97% for M 2 Treatment. Toxocara spp., Hookworm spp., Trichuris spp., Capillaria spp., and Shistosoma spp. eggs were totally eliminated (100% decrease) and the Taenia spp. was absent from the first stage of composting. These results confirm the effectiveness of both dehydrating and composting processes on the removal of helminth eggs.

The effect of lime-dried sewage sludge on the heat-resistance of eco-cement.

PubMed

Li, Wen-Quan; Liu, Wei; Cao, Hai-Hua; Xu, Jing-Cheng; Liu, Jia; Li, Guang-Ming; Huang, Juwen

2016-01-01

The treatment and disposal of sewage sludge is a growing problem for sewage treatment plants. One method of disposal is to use sewage sludge as partial replacement for raw material in cement manufacture. Although this process has been well researched, little attention has been given to the thermal properties of cement that has had sewage sludge incorporated in the manufacturing process. This study investigated the fire endurance of eco-cement to which lime-dried sludge (LDS) had been added. LDS was added in proportions of 0%, 3%, 6%, 9%, and 12% (by weight) to the raw material. The eco-cement was exposed to 200, 400, or 600 °C for 3 h. The residual strength and the microstructural properties of eco-cement were then studied. Results showed that the eco-cement samples suffered less damage than conventional cement at 600 °C. The microstructural studies showed that LDS incorporation could reduce Ca(OH)(2) content. It was concluded that LDS has the potential to improve the heat resistance of eco-cement products.

Effect of sludge features and extraction-esterification technology on the synthesis of biodiesel from secondary wastewater treatment sludges.

PubMed

Patiño, Yolanda; Mantecón, Laura G; Polo, Sara; Faba, Laura; Díaz, Eva; Ordóñez, Salvador

2018-01-01

Secondary sludge from municipal wastewater treatment plant is proposed as a promising alternative lipid feedstock for biodiesel production. A deep study combining different type of raw materials (sludge coming from the oxic, anoxic and anaerobic steps of the biological treatment) with different technologies (liquid-liquid and solid-liquid extractions followed by acid catalysed transesterification and in situ extraction-transesterification procedure) allows a complete comparison of available technologies. Different parameters - contact time, catalyst concentration, pretreatments - were considered, obtaining more than 17% FAMEs yield after 50min of sonication with the in situ procedure and 5% of H 2 SO 4 . This result corresponds to an increment of more than 65% respect to the best results reported at typical conditions. Experimental data were used to propose a mathematical model for this process, demonstrating that the mass transfer of lipids from the sludge to the liquid is the limiting step. Copyright © 2017 Elsevier Ltd. All rights reserved.

Behaviour of endocrine disrupting chemicals during the treatment of municipal sewage sludge.

PubMed

Ivashechkin, P; Corvini, P F X; Dohmann, M

2004-01-01

Agricultural application of municipal sewage sludge has been emotionally discussed in the last decades, because the latter contains endocrine disrupting chemicals (EDCs) and other organic micropollutants with unknown fate and risk potential. Bisphenol A (BPA) was chosen as a model substance to investigate the influence of sludge conditioning on the end-concentration of EDCs in sludge. Adsorption studies with radioactive-labelled BPA showed that more than 75% BPA in anaerobically digested sludge is bound to solids (log Kd = 2.09-2.30; log Koc = 2.72-3.11). Sludge conditioning with polymer or iron (III) chloride alone had no influence on the adsorption of BPA. After conditioning with iron (III) chloride and calcium hydroxide desorption of BPA took place. Apparently, it occurred due to the deprotonation of BPA (pKa= 10.3) as the pH-value reached 12.4 during the process. The same behaviour is expected for other phenolic EDCs with similar pKa (nonylphenol, 17beta-estradiol, estron, estriol, 17alpha-ethinylestradiol). This study shows high affinity of BPA to the anaerobically digested sludge and importance of conditioning in the elimination of EDCs during the sludge treatment. Addition of polymer is favourable in the case of sludge incineration. Conditioning with iron (III) chloride and calcium hydroxide shows advantages for the use of sludge as fertiliser.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis.

PubMed

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin

2015-01-01

Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric-differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175-300°C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others. Copyright © 2014 Elsevier Ltd. All rights reserved.

SLUDGE TREATMENT PROJECT PHASE 1 SLUDGE STORAGE OPTIONS ASSESSMENT OF T PLANT VERSUS ALTERNATE STORAGE FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

RUTHERFORD WW; GEUTHER WJ; STRANKMAN MR

2009-04-29

The CH2M HILL Plateau Remediation Company (CHPRC) has recommended to the U.S. Department of Energy (DOE) a two phase approach for removal and storage (Phase 1) and treatment and packaging for offsite shipment (Phase 2) of the sludge currently stored within the 105-K West Basin. This two phased strategy enables early removal of sludge from the 105-K West Basin by 2015, allowing remediation of historical unplanned releases of waste and closure of the 100-K Area. In Phase 1, the sludge currently stored in the Engineered Containers and Settler Tanks within the 105-K West Basin will be transferred into sludge transportmore » and storage containers (STSCs). The STSCs will be transported to an interim storage facility. In Phase 2, sludge will be processed (treated) to meet shipping and disposal requirements and the sludge will be packaged for final disposal at a geologic repository. The purpose of this study is to evaluate two alternatives for interim Phase 1 storage of K Basin sludge. The cost, schedule, and risks for sludge storage at a newly-constructed Alternate Storage Facility (ASF) are compared to those at T Plant, which has been used previously for sludge storage. Based on the results of the assessment, T Plant is recommended for Phase 1 interim storage of sludge. Key elements that support this recommendation are the following: (1) T Plant has a proven process for storing sludge; (2) T Plant storage can be implemented at a lower incremental cost than the ASF; and (3) T Plant storage has a more favorable schedule profile, which provides more float, than the ASF. Underpinning the recommendation of T Plant for sludge storage is the assumption that T Plant has a durable, extended mission independent of the K Basin sludge interim storage mission. If this assumption cannot be validated and the operating costs of T Plant are borne by the Sludge Treatment Project, the conclusions and recommendations of this study would change. The following decision-making strategy, which is dependent on the confidence that DOE has in the long term mission for T Plant, is proposed: (1) If the confidence level in a durable, extended T Plant mission independent of sludge storage is high, then the Sludge Treatment Project (STP) would continue to implement the path forward previously described in the Alternatives Report (HNF-39744). Risks to the sludge project can be minimized through the establishment of an Interface Control Document (ICD) defining agreed upon responsibilities for both the STP and T Plant Operations regarding the transfer and storage of sludge and ensuring that the T Plant upgrade and operational schedule is well integrated with the sludge storage activities. (2) If the confidence level in a durable, extended T Plant mission independent of sludge storage is uncertain, then the ASF conceptual design should be pursued on a parallel path with preparation of T Plant for sludge storage until those uncertainties are resolved. (3) Finally, if the confidence level in a durable, extended T Plant mission independent of sludge storage is low, then the ASF design should be selected to provide independence from the T Plant mission risk.« less

Operational Control Procedures for the Activated Sludge Process, Part I - Observations, Part II - Control Tests.

ERIC Educational Resources Information Center

West, Alfred W.

This is the first in a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. Part I of this document deals with physical observations which should be performed during each routine control test. Part II…

K Basins sludge removal temporary sludge storage tank system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mclean, M.A.

1997-06-12

Shipment of sludge from the K Basins to a disposal site is now targeted for August 2000. The current path forward for sludge disposal is shipment to Tank AW-105 in the Tank Waste Remediation System (TWRS). Significant issues of the feasibility of this path exist primarily due to criticality concerns and the presence of polychlorinated biphenyls (PCBS) in the sludge at levels that trigger regulation under the Toxic Substance Control Act. Introduction of PCBs into the TWRS processes could potentially involve significant design and operational impacts to both the Spent Nuclear Fuel and TWRS projects if technical and regulatory issuesmore » related to PCB treatment cannot be satisfactorily resolved. Concerns of meeting the TWRS acceptance criteria have evolved such that new storage tanks for the K Basins sludge may be the best option for storage prior to vitrification of the sludge. A reconunendation for the final disposition of the sludge is scheduled for June 30, 1997. To support this decision process, this project was developed. This project provides a preconceptual design package including preconceptual designs and cost estimates for the temporary sludge storage tanks. Development of cost estimates for the design and construction of sludge storage systems is required to help evaluate a recommendation for the final disposition of the K Basin sludge.« less

Removal of pharmaceuticals from wastewater by biological processes, hydrodynamic cavitation and UV treatment.

PubMed

Zupanc, Mojca; Kosjek, Tina; Petkovšek, Martin; Dular, Matevž; Kompare, Boris; Širok, Brane; Blažeka, Željko; Heath, Ester

2013-07-01

To augment the removal of pharmaceuticals different conventional and alternative wastewater treatment processes and their combinations were investigated. We tested the efficiency of (1) two distinct laboratory scale biological processes: suspended activated sludge and attached-growth biomass, (2) a combined hydrodynamic cavitation-hydrogen peroxide process and (3) UV treatment. Five pharmaceuticals were chosen including ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac, and an active metabolite of the lipid regulating agent clofibric acid. Biological treatment efficiency was evaluated using lab-scale suspended activated sludge and moving bed biofilm flow-through reactors, which were operated under identical conditions in respect to hydraulic retention time, working volume, concentration of added pharmaceuticals and synthetic wastewater composition. The suspended activated sludge process showed poor and inconsistent removal of clofibric acid, carbamazepine and diclofenac, while ibuprofen, naproxen and ketoprofen yielded over 74% removal. Moving bed biofilm reactors were filled with two different types of carriers i.e. Kaldnes K1 and Mutag BioChip™ and resulted in higher removal efficiencies for ibuprofen and diclofenac. Augmentation and consistency in the removal of diclofenac were observed in reactors using Mutag BioChip™ carriers (85%±10%) compared to reactors using Kaldnes carriers and suspended activated sludge (74%±22% and 48%±19%, respectively). To enhance the removal of pharmaceuticals hydrodynamic cavitation with hydrogen peroxide process was evaluated and optimal conditions for removal were established regarding the duration of cavitation, amount of added hydrogen peroxide and initial pressure, all of which influence the efficiency of the process. Optimal parameters resulted in removal efficiencies between 3-70%. Coupling the attached-growth biomass biological treatment, hydrodynamic cavitation/hydrogen peroxide process and UV treatment resulted in removal efficiencies of >90% for clofibric acid and >98% for carbamazepine and diclofenac, while the remaining compounds were reduced to levels below the LOD. For ibuprofen, naproxen, ketoprofen and diclofenac the highest contribution to overall removal was attributed to biological treatment, for clofibric acid UV treatment was the most efficient, while for carbamazepine hydrodynamic cavitation/hydrogen peroxide process and UV treatment were equally efficient. Copyright © 2012 Elsevier B.V. All rights reserved.

Sequential anaerobic/aerobic digestion for enhanced sludge stabilization: comparison of the process performance for mixed and waste sludge [corrected].

PubMed

Tomei, M Concetta; Carozza, Nicola Antonello

2015-05-01

Sequential anaerobic-aerobic digestion has been demonstrated as a promising alternative for enhanced sludge stabilization. In this paper, a feasibility study of the sequential digestion applied to real waste activated sludge (WAS) and mixed sludge is presented. Process performance is evaluated in terms of total solid (TS) and volatile solid (VS) removal, biogas production, and dewaterability trend in the anaerobic and double-stage digested sludge. In the proposed digestion lay out, the aerobic stage was operated with intermittent aeration to reduce the nitrogen load recycled to the wastewater treatment plant (WWTP). Experimental results showed a very good performance of the sequential digestion process for both waste and mixed sludge, even if, given its better digestibility, higher efficiencies are observed for mixed sludge. VS removal efficiencies in the anaerobic stage were 48 and 50% for waste and mixed sludge, respectively, while a significant additional improvement of the VS removal of 25% for WAS and 45% for mixed sludge has been obtained in the aerobic stage. The post-aerobic stage, operated with intermittent aeration, was also efficient in nitrogen removal, providing a significant decrease of the nitrogen content in the supernatant: nitrification efficiencies of 90 and 97% and denitrification efficiencies of 62 and 70% have been obtained for secondary and mixed sludges, respectively. A positive effect due to the aerobic stage was also observed on the sludge dewaterability in both cases. Biogas production, expressed as Nm(3)/(kgVSdestroyed), was 0.54 for waste and 0.82 for mixed sludge and is in the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days.

Sewage sludge additive

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

1980-01-01

The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

EMERGING CLASS A PROCESSES - A DISCUSSION OF NOVEL APPROACHES TO MEETING CLASS A, ALTERNATIVES 1, 3 AND 4; AND EMERGING TECHNOLOGIES APPLYING FOR A PFRP EQUIVALENCY UNDER CLASS A, ALTERNATIVE 6.

EPA Science Inventory

Pathogenic microorganisms enter the wastewater collection system from many sources including hospitals, slaughter houses and schools. During treatment at the wastewater treatment plant they become concentrated in the sewage sludge. Prior to any kind of beneficial use the sludge m...

Problematic issues of air protection during thermal processes related to the energetic uses of sewage sludge and other waste. Case study: Co-combustion in peaking power plant.

PubMed

Hroncová, Emília; Ladomerský, Juraj; Musil, Juraj

2018-03-01

Currently, it is necessary to deal with issues related to the emissions as there is a constantly increasing interest in combusting sludge from sewage treatment plants in the boilers for wood. An analysis of the energetic importance of the combustion of sewage sludge has already been carried out, but the effects of various treatments of the sludge are not always clear, e.g. composting and subsequent combustion to the air pollution. Investments in other thermal processes of energetic utilisation of sewage sludge and organic waste are not always successfully implemented. The objective of this paper is to point out some problematic cases for acceptance of thermal processes related to energetic use of waste in terms of the air protection. The other aim is to mention the experience with solutions of such issues in Slovakia. There are mentioned first results of the operational validation experiments during the energy generation in circulating fluidized bed boiler in peaking power plant (Power 110MW) with the addition of the so-called alternative fuel based on wood and sewage sludge to the main fuel - black coal (anthracite). And there has already been achieved the highest share of 12.4%w. (dry matter) of sewage sludge in form of compost in blend with black coal, which is technologically viable. Moreover analyzed the problems of the authorization and operation of the co-combustion of sewage sludge and of combustion of products of various kinds of pyrolysis waste - pyrolysis gas and pyrolysis oil are analyzed. Copyright © 2017 Elsevier Ltd. All rights reserved.

TREATMENT OF MUNICIPAL SLUDGE FOR PATHOGEN REDUCTION

EPA Science Inventory

This presentation reviews the pathogenic microorganisms that may be found in municipal sewage sludge and the commonly employed Class A and B processes for controlling pathogens. It notes how extensively they are used and discusses issues and concerns with their application. The...

Biogas: Production and utilization

NASA Astrophysics Data System (ADS)

Price, E. C.; Cheremisinoff, P. N.

Among the aspects of biogas production and utilization covered are: (1) the microbiology and biochemistry of the acid and methane production stages in the anaerobic process; (2) factors affecting the process, such as temperature, acidity and alkalinity, nutrients, and cations; (3) denitrification processes and systems; and (4) the process kinetics of suspended growth systems, packed columns, and fluidized beds. Also considered are such issues in the application of this technology as the digestion of municipal treatment plant sludges, animal wastes, food processing wastes and energy crops. Attention is in addition given to anaerobic digester design, offgas measurement of anaerobic digesters, and sludge treatment through soil conditioning and composting.

Electricity production and sludge reduction by integrating microbial fuel cells in anoxic-oxic process.

PubMed

Xiao, Benyi; Luo, Meng; Wang, Xiao; Li, Zuoxing; Chen, Hong; Liu, Junxin; Guo, Xuesong

2017-11-01

To produce energy and reduce sludge production from the treatment of municipal wastewater, four identical microbial fuel cells (MFCs) were constructed in an anoxic-oxic (A/O) process (MFCs-A/O system). Experimental results indicated that this system enhance the removals of chemical oxygen demand (COD) and total nitrogen (TN). The electricity produced by each MFC were ranged from 0.371 to 0.477V (voltage) and from 138 to 227mW/m 3 (power density) at the stable stage, when the external resistance was fixed at 1000Ω. The coulombic efficiency of the MFCs-A/O system ranged from 0.31% to 1.68% (mean=0.72%) at the stable stage, respectively. The removals of COD and TN in the MFCs-A/O system were slightly higher than those in the control system. Compared with the control system, the MFCs-A/O system can reduce waste activated sludge production and sludge yield by 24.0% and 24.2%, respectively. The experimental results indicated that the MFC constructed in A/O system improves wastewater treatment and the MFCs-A/O system can produce electricity while reducing sludge production and increasing wastewater treatment efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occurrence and removal of Giardia spp. cysts and Cryptosporidium spp. oocysts from a municipal wastewater treatment plant in Brazil.

PubMed

Santos, Priscila Ribeiro Dos; Daniel, Luiz Antonio

2017-05-01

Sewage and sewage sludge have been recognized as potential sources of two important waterborne pathogenic protozoa: Giardia spp. and Cryptosporidium spp. Due to the lack of studies about the occurrence of these pathogens in sewage and sludge in Brazil, an investigation was conducted at various stages of a municipal wastewater treatment plant (WWTP) aiming to assess the occurrence of Giardia spp. cysts and Cryptosporidium spp. oocysts, their removal by the treatment processes, which are upflow anaerobic sludge blanket (UASB) reactor and dissolved air flotation process, and also the correlations between protozoa and indicator microorganisms. Significant quantities of cysts were detected in 100% of the analyzed wastewater samples, while oocysts were detected only in 39.0% of all wastewater samples. The overall removal of Giardia spp. cysts from the WWTP was on average 2.03 log, and the UASB reactor was more efficient than flotation. The sludge samples presented high quantities of (oo)cysts, implying the risks of contamination in the case of sludge reuse or inadequate disposal. Giardiasis prevalence was estimated between 2.21% and 6.7% for the population served by the WWTP, while cryptosporidiosis prevalence was much lower. Significant positive correlation was obtained only between cysts and Clostridium spores in anaerobic effluent.

Rheological and electrical properties used to investigate the coagulation process during sludge treatment.

PubMed

Mortadi, A; El Melouky, A; Chahid, E; Nasrellah, H; Bakasse, M; Zradba, A; Cherkaoui, O; El Moznine, R

2018-01-01

Analyses of rheological properties and electrical conductivity (σ dc ) at direct current have been employed in order to investigate the effects of calcium oxide on the coagulation process during sludge treatment in the textile industry. In this context, rheological and electrical measurements were performed on five samples - one that contained raw sludge and the other four that were prepared from the raw sludge and different amounts of calcium oxide: 2, 3, 4, 5% (w/w). Rheological behavior of these samples was analyzed using the Herschel-Bulkley modified model. The influence of calcium oxide content on the rheological parameters such as infinite viscosity, the yield stress, the consistency coefficient, and the consistency index, are presented and discussed. The impact of the calcium oxide content on pH and conductivity were also examined. Similar behaviors have been seen in the evolution of conductivity and infinite viscosity as a function of the calcium oxide content. These latter characteristics were modeled by an equation using two power laws. This equation was able to fit very well the evolution of electrical conductivity and also the viscosity versus the percentage of calcium oxide to predict the optimal amount of calcium oxide (3%) to achieve the coagulation step during sludge treatment.

[Analysis and research on the degradation and migration of organic pollutants in textile wastewater treatment process by GC-MS].

PubMed

Liu, Wei-jing; Zhang, Long; Wu, Wei; Tu, Yong

2010-04-01

In order to analyze the advantages/disadvantages of the combined treatment process between "physicochemical + biochemical" and "biochemical + physicochemical" in treatment of textile wastewater, gas chromatography-mass spectrometry (GC-MS) was used to determine the degradation process of organic pollutants in this two totally different treatment processes. The same analysis was also conducted to the sludge and discharged water. The results showed that the "physicochemical + biochemical" process displayed a poorer effect than "biochemical + physicochemical" in degrading the organic pollutants. The latter was 6.2% higher than the former in removing the organic pollutants averagely. The difference was mainly manifested in the efficiency of anaerobic hydrolysis in the two coupled processes. Moreover, the implement of "physicochemical + biochemical" process resulted in the migration of plenty of typical organic pollutants to sludge from primary coagulation sedimentation process and to the discharged water, which would cause secondary pollution easily.

Previously unclassified bacteria dominate during thermophilic and mesophilic anaerobic pre-treatment of primary sludge.

PubMed

Pervin, Hasina M; Batstone, Damien J; Bond, Philip L

2013-06-01

Thermophilic biological pre-treatment enables enhanced anaerobic digestion for treatment of wastewater sludges but, at present, there is limited understanding of the hydrolytic-acidogenic microbial composition and its contribution to this process. In this study, the process was assessed by comparing the microbiology of thermophilic (50-65 °C) and mesophilic (35 °C) pre-treatment reactors treating primary sludge. A full-cycle approach for the 16S rRNA genes was applied in order to monitor the diversity of bacteria and their abundance in a thermophilic pre-treatment reactor treating primary sludge. For the thermophilic pre-treatment (TP), over 90% of the sequences were previously undetected and these had less than 97% sequence similarity to cultured organisms. During the first 83 days, members of the Betaproteobacteria dominated the community sequences and a newly designed probe was used to monitor a previously unknown bacterium affiliated with the genus Brachymonas. Between days 85 and 183, three phylotypes that affiliated with the genera Comamonas, Clostridium and Lysobacter were persistently dominant in the TP community, as revealed by terminal-restriction fragment length polymorphism (T-RFLP). Hydrolytic and fermentative functions have been speculated for these bacteria. Mesophilic pre-treatment (MP) and TP communities were different but they were both relatively dynamic. Statistical correlation analysis and the function of closely allied reference organisms indicated that previously unclassified bacteria dominated the TP community and may have been functionally involved in the enhanced hydrolytic performance of thermophilic anaerobic pre-treatment. This study is the first to reveal the diversity and dynamics of bacteria during anaerobic digestion of primary sludge. Copyright © 2013 Elsevier GmbH. All rights reserved.

Plant-wide (BSM2) evaluation of reject water treatment with a SHARON-Anammox process.

PubMed

Volcke, E I P; Gernaey, K V; Vrecko, D; Jeppsson, U; van Loosdrecht, M C M; Vanrolleghem, P A

2006-01-01

In wastewater treatment plants (WWTPs) equipped with sludge digestion and dewatering systems, the reject water originating from these facilities contributes significantly to the nitrogen load of the activated sludge tanks, to which it is typically recycled. In this paper, the impact of reject water streams on the performance of a WWTP is assessed in a simulation study, using the Benchmark Simulation Model no. 2 (BSM2), that includes the processes describing sludge treatment and in this way allows for plant-wide evaluation. Comparison of performance of a WWTP without reject water with a WWTP where reject water is recycled to the primary clarifier, i.e. the BSM2 plant, shows that the ammonium load of the influent to the primary clarifier is 28% higher in the case of reject water recycling. This results in violation of the effluent total nitrogen limit. In order to relieve the main wastewater treatment plant, reject water treatment with a combined SHARON-Anammox process seems a promising option. The simulation results indicate that significant improvements of the effluent quality of the main wastewater treatment plant can be realized. An economic evaluation of the different scenarios is performed using an Operating Cost Index (OCI).

Treatment of old landfill leachate with high ammonium content using aerobic granular sludge.

PubMed

Ren, Yanan; Ferraz, Fernanda; Kang, Abbass Jafari; Yuan, Qiuyan

2017-01-01

Aerobic granular sludge has become an attractive alternative to the conventional activated sludge due to its high settling velocity, compact structure, and higher tolerance to toxic substances and adverse conditions. Aerobic granular sludge process has been studied intensively in the treatment of municipal and industrial wastewater. However, information on leachate treatment using aerobic granular sludge is very limited. This study investigated the treatment performance of old landfill leachate with different levels of ammonium using two aerobic sequencing batch reactors (SBR): an activated sludge SBR (ASBR) and a granular sludge SBR (GSBR). Aerobic granules were successfully developed using old leachate with low ammonium concentration (136 mg L -1  NH 4 + -N). The GSBR obtained a stable chemical oxygen demand (COD) removal of 70% after 15 days of operation; while the ASBR required a start-up of at least 30 days and obtained unstable COD removal varying from 38 to 70%. Ammonium concentration was gradually increased in both reactors. Increasing influent ammonium concentration to 225 mg L -1  N, the GSBR removed 73 ± 8% of COD; while COD removal of the ASBR was 59 ± 9%. The GSBR was also more efficient than the ASBR for nitrogen removal. The granular sludge could adapt to the increasing concentrations of ammonium, achieving 95 ± 7% removal efficiency at a maximum influent concentration of 465 mg L -1  N. Ammonium removal of 96 ± 5% was obtained by the ASBR when it was fed with a maximum of 217 mg L -1  NH 4 + -N. However, the ASBR was partially inhibited by free-ammonia and nitrite accumulation rate increased up to 85%. Free-nitrous acid and the low biodegradability of organic carbon were likely the main factors affecting phosphorus removal. The results from this research suggested that aerobic granular sludge have advantage over activated sludge in leachate treatment.

PROCESS DESIGN MANUAL: LAND APPLICATION OF ...

EPA Pesticide Factsheets

Land application of sewage sludge generated by domestic sewage treatment is performed in an environmentally safe and cost–effective manner in many communities. Land application involves taking advantage of the fertilizing and soil conditioning properties of sewage sludge by spreading the sewage sludge on the soil surface, incorporating or injecting the sewage sludge into soil, or spraying the sewage sludge. Because sewage sludge disposal practices (e.g., landfilling) are becoming less available and more costly, and because of the increasing desire to beneficially reuse waste residuals whenever possible, land application is increasingly chosen as a sewage sludge use or disposal practice. Approximately 33 percent of the 5.4 million dry metric tons of sewage sludge generated annually in the United States at publicly owned treatment works (POTWs) is land applied. Of the sewage sludge that is land applied, approximately 67% is land applied on agricultural lands, 3% on forest lands, approximately 9% on reclamation sites, and 9% on public contact sites; 12% is sold or given away in a bag or other container for application to the land (Federal Register, Vol. 58, No. 32, February 19, 1993). In addition, approximately 8.6 billion gallons of domestic septage is generated annually. Land application of sewage sludge has been practiced in many countries for centuries so that the nutrients (e.g., nitrogen, phosphorus) and organic matter in sewage sludge can be beneficia

Life cycle assessment of sewage sludge co-incineration in a coal-based power station.

PubMed

Hong, Jingmin; Xu, Changqing; Hong, Jinglan; Tan, Xianfeng; Chen, Wei

2013-09-01

A life cycle assessment was conducted to evaluate the environmental and economic effects of sewage sludge co-incineration in a coal-fired power plant. The general approach employed by a coal-fired power plant was also assessed as control. Sewage sludge co-incineration technology causes greater environmental burden than does coal-based energy production technology because of the additional electricity consumption and wastewater treatment required for the pretreatment of sewage sludge, direct emissions from sludge incineration, and incinerated ash disposal processes. However, sewage sludge co-incineration presents higher economic benefits because of electricity subsidies and the income generating potential of sludge. Environmental assessment results indicate that sewage sludge co-incineration is unsuitable for mitigating the increasing pressure brought on by sewage sludge pollution. Reducing the overall environmental effect of sludge co-incineration power stations necessitates increasing net coal consumption efficiency, incinerated ash reuse rate, dedust system efficiency, and sludge water content rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Water reduction in waste-activated sludge by resettling and filtration in batch. Phase (1): pilot-scale experiments to optimize performance.

PubMed

Trapote, Arturo; Jover, Margarita; Cartagena, Pablo; El Kaddouri, Marouane; Prats, Daniel

2014-08-01

This article describes an effective procedure for reducing the water content of excess sludge production from a wastewater treatment plant by increasing its concentration and, as a consequence, minimizing the volume of sludge to be managed. It consists of a pre-dewatering sludge process, which is used as a preliminary step or alternative to the thickening. It is made up of two discontinuous sequential stages: the first is resettling and the second, filtration through a porous medium. The process is strictly physical, without any chemical additives or electromechanical equipment intervening. The experiment was carried out in a pilot-scale system, consisting of a column of sedimentation that incorporates a filter medium. Different sludge heights were tested over the filter to verify the influence ofhydrostatic pressure on the various final concentrations of each stage. The results show that the initial sludge concentration may increase by more than 570% by the end of the process with the final volume of sludge being reduced in similar proportions and hydrostatic pressure having a limited effect on this final concentration. Moreover, the value of the hydrostatic pressure at which critical specific cake resistance is reached is established.

Complete solids retention activated sludge process.

PubMed

Amanatidou, E; Samiotis, G; Trikoilidou, E; Pekridis, G; Tsikritzis, L

2016-01-01

In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases in correlation to sludge biological and morphological characteristics were studied. Three distinguished growth phases were observed during the 425 days of monitoring. The imposed operational conditions led the process to extended biomass starvation conditions, minimum F/M, minimum SUR and predator species growth. MLSS and MLVSS reached a stabilization phase (plateau phase) where almost zero sludge accumulation was observed. The concept of degradation of the considered non-biodegradable particulate compounds in influent and in biomass (cell debris) was also studied. Comparison of evolution of observed sludge yields (Yobs) in the WWTP with Yobs predictions by activated sludge models verified the degradation concept for the considered non-biodegradable compounds. Control of the sedimentation process was achieved, by predicting the solids loading rate critical point using state point analysis and stirred/unstirred settling velocity tests and by applying a high return activated sludge rate. The nitrogen gas related sedimentation problems were taken into consideration.

Sludge reduction and microbial community structure in an anaerobic/anoxic/oxic process coupled with potassium ferrate disintegration.

PubMed

An, Ying; Zhou, Zhen; Yao, Jie; Niu, Tianhao; Qiu, Zhan; Ruan, Danian; Wei, Haijuan

2017-12-01

An anaerobic/anoxic/oxic (AAO) wastewater treatment system combining with a potassium ferrate (K 2 FeO 4 ) oxidation side-stream reactor (SSR) was proposed for sludge reduction. Batch experiments showed that optimal K 2 FeO 4 dosage and reaction time for sludge disintegration was 100mg/g suspended solids (SS) and 24h, respectively. Subsequently, an AAO-SSR and a conventional AAO were operated in parallel to investigate effects of K 2 FeO 4 oxidation on process performance, sludge characteristics and microbial community structures. The AAO-SSR process operated under the optimized condition achieved efficient COD and NH 4 + -N removal, and reduced sludge by 47.5% with observed yield coefficient of 0.21gSS/g COD. K 2 FeO 4 addition broke sludge particles, increased dissolved organic matters in the mixed liquor, and improved sludge dewaterability. Illumina-MiSeq sequencing results showed that K 2 FeO 4 oxidation in the AAO-SSR decreased microbial richness and diversity, enriched slow growers (Dechloromonas), anaerobic fermentative bacteria (Azospira) and Fe(III)-reducing bacteria (Ferribacterium), but limited the growth of phosphate-accumulating organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review on innovative techniques in oil sludge bioremediation

NASA Astrophysics Data System (ADS)

Mahdi, Abdullah M. El; Aziz, Hamidi Abdul; Eqab, Eqab Sanoosi

2017-10-01

Petroleum hydrocarbon waste is produced in worldwide refineries in significant amount. In Libya, approximately 10,000 tons of oil sludge is generated in oil refineries (hydrocarbon waste mixtures) annually. Insufficient treatment of those wastes can threaten the human health and safety as well as our environment. One of the major challenges faced by petroleum refineries is the safe disposal of oil sludge generated during the cleaning and refining process stages of crude storage facilities. This paper reviews the hydrocarbon sludge characteristics and conventional methods for remediation of oil hydrocarbon from sludge. This study intensively focuses on earlier literature to describe the recently selected innovation technology in oily hydrocarbon sludge bioremediation process. Conventional characterization parameters or measurable factors can be gathered in chemical, physical, and biological parameters: (1) Chemical parameters are consequently necessary in the case of utilization of topsoil environment when they become relevant to the presence of nutrients and toxic compounds; (2) Physical parameters provide general data on sludge process and hand ability; (3) Biological parameters provide data on microbial activity and organic matter presence, which will be used to evaluate the safety of the facilities. The objective of this research is to promote the bioremediating oil sludge feasibility from Marsa El Hariga Terminal and Refinery (Tobruk).

Monitoring of activated sludge settling ability through image analysis: validation on full-scale wastewater treatment plants.

PubMed

Mesquita, D P; Dias, O; Amaral, A L; Ferreira, E C

2009-04-01

In recent years, a great deal of attention has been focused on the research of activated sludge processes, where the solid-liquid separation phase is frequently considered of critical importance, due to the different problems that severely affect the compaction and the settling of the sludge. Bearing that in mind, in this work, image analysis routines were developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments in eight different wastewater treatment plants, for a combined period of 2 years. The monitoring of the activated sludge contents allowed for the detection of bulking events proving that the developed image analysis methodology is adequate for a continuous examination of the morphological changes in microbial aggregates and subsequent estimation of the sludge volume index. In fact, the obtained results proved that the developed image analysis methodology is a feasible method for the continuous monitoring of activated sludge systems and identification of disturbances.

Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants.

PubMed

Pan, Yuting; Ye, Liu; van den Akker, Ben; Ganigué Pagès, Ramon; Musenze, Ronald S; Yuan, Zhiguo

2016-02-02

"Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.

Estrogenic compounds in Tunisian urban sewage treatment plant: occurrence, removal and ecotoxicological impact of sewage discharge and sludge disposal.

PubMed

Belhaj, Dalel; Athmouni, Khaled; Jerbi, Bouthaina; Kallel, Monem; Ayadi, Habib; Zhou, John L

2016-12-01

The occurrence, fate and ecotoxicological assessment of selected estrogenic compounds were investigated at Tunisian urban sewage treatment plant. The influents, effluents, as well as primary, secondary and dehydrated sludge, were sampled and analyzed for the target estrogens to evaluate their fate. All target compounds were detected in both sewage and sludge with mean concentrations from 0.062 to 0.993 μg L -1 and from 11.8 to 792.9 μg kg -1 dry weight, respectively. A wide range of removal efficiencies during the treatment processes were observed, from 6.3 % for estrone to 76.8 % for estriol. Ecotoxicological risk assessment revealed that the highest ecotoxicological risk in sewage effluent and dehydrated sludge was due to 17β-estradiol with a risk quotient (RQ) of 4.6 and 181.9, respectively, and 17α-ethinylestradiol with RQ of 9.8 and 14.85, respectively. Ecotoxicological risk after sewage discharge and sludge disposal was limited to the presence of 17β-estradiol in dehydrated-sludge amended soil with RQ of 1.38. Further control of estrogenic hormones in sewage effluent and sludge is essential before their discharge and application in order to prevent their introduction into the natural environment.

[Inhibition of Denitrification by Total Phenol Load of Coal Gasification Wastewater].

PubMed

Zhang, Yu-ying; Chen, Xiu-rong; Wang, Lu; Li, Jia-hui; Xu, Yan; Zhuang, You-jun; Yu, Ze-ya

2016-03-15

High loaded phenolic pollutants, refractory and high toxic, which existed in coal gasification wastewater, could cause the inhibition of sludge activity. In biological denitrification process of activated sludge treatment system, people tend to focus on the phenol inhibition on the efficiency and activity of nitrifying bacteria while there are few researches on the denitrification process. In order to investigate the inhibition of phenolic compounds from coal gasification wastewater on the denitrification and sludge activity, we used anoxic denitrification system to indentify the influence of different phenol load on denitrification efficiency (removal efficiency of NO₃⁻-N and NO₂⁻-N) as well as the stress and degradation activity of sludge. The results showed that when the concentration of total phenol was changed from 50 mg · L⁻¹ to 200 mg · L⁻¹, the removal rates of NO₃⁻-N and NO₂⁻-N were changed from 55% and 25% to 83% and 83% respectively. In the process of sludge domestication, the characteristics of denitrifying sludge were influenced to a certain degree.

Characterization of water treatment sludge and its reuse as coagulant.

PubMed

Ahmad, Tarique; Ahmad, Kafeel; Ahad, Abdul; Alam, Mehtab

2016-11-01

Coagulation-flocculation process results in the generation of large volume of waste or residue, known as water treatment sludge (WTS), in the purification of surface water for potable supplies. Sustainable management of the inevitable waste requires careful attention from the plant operators and sludge managers. In this study, WTS produced with the optimum alum dose of 30 ml/L at the laboratory scale has been treated with sulphuric acid to bring forth a product known as sludge reagent product (SRP). The performance of SRP is evaluated for its efficiency in removing the colloidal suspensions from the Yamuna river water over wide pH range of 2-13. 1% sludge acidified with sulphuric acid of normality 2.5 at the rate of 0.05 ml/ml sludge has been observed as the optimum condition for preparing SRP from WTS. The percentage turbidity removal is greater at higher pH value and increases with increasing the dosage of SRP. The optimum SRP dosage of 8 ml/L in the pH range of 6-8 performed well in removing the colloidal suspension and other impurities from the Yamuna water. The quality of treated water met the prescribed standards for most of the quality parameters. Thus, SRP has the potential to substitute the conventional coagulants partially or completely in the water treatment process, depending on the quality needed at the users end. Copyright © 2016 Elsevier Ltd. All rights reserved.

Monitoring and troubleshooting of non-filamentous settling and dewatering problems in an industrial activated sludge treatment plant.

PubMed

Kjellerup, B V; Keiding, K; Nielsen, P H

2001-01-01

A large industrial activated sludge wastewater treatment plant had temporary problems with settling and dewatering of the sludge. Microscopical investigations revealed that the poor settling properties were not due to presence of filamentous bacteria, but poor floc properties. In order to characterise the changes in floc properties that led to settling and dewatering problems and to find reasons for this taking place, a comprehensive monitoring program was conducted during more than one year. The monitoring program included various measurements of floc settleability, floc strength and sludge dewaterability. The monitoring program revealed that a deterioration of the floc strength and the settling properties in the process tanks was closely connected to downstream dewatering problems and poor effluent quality. Particularly severe problems were observed a few weeks after the production at the factory had started after summer closedown. Possible reasons for the changes in floc properties in the process tanks were found by a) analysing change in wastewater composition by evaluating the different production lines in the industrial plant, b) evaluating the operation of the plant, and c) performing short-term laboratory experiments testing factors that could potentially affect floc properties (absence of oxygen, presence of sulphide, detergents, etc). Among several measured parameters, the use of floc strength measurements in particular proved useful to monitor the activated sludge floc properties at this industrial plant. The described strategy can be useful in general to find and solve many solid/liquid separation problems in activated sludge wastewater treatment plants.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Meiyan; Xiao, Benyi; Wang, Xu

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewagemore » sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.« less

Improving anaerobic and aerobic degradation by ultrasonic disintegration of biomass.

PubMed

Neis, Uwe; Nickel, Klaus; Lundén, Anna

2008-11-01

Biological cell lysis is known to be the rate-limiting step of anaerobic biosolids degradation. Due to the slow pace by which this reaction occurs, it is necessary to equip treatment plants with large digesters or alternatively incorporate technological aids. High-power ultrasound used to disintegrate bacterial cells has been utilized as a pre-treatment process prior to anaerobic digestion. Through this application, as seen on pilot- and full-scales, it is possible to attain up to 30% more biogas, an increase in VS-destruction of up to 30% and a reduced sludge mass for disposal. Utilizing ultrasound technology in aerobic applications is a new and innovative approach. Improved denitrification through a more readily available internal carbon source, and less excess sludge mass can be traced to the positive effects that sonication of sludge has on the overall biological wastewater treatment process. Reference full-scale installations suggest that the technology is both technically feasible and economically sound.

Electricity generation and in situ phosphate recovery from enhanced biological phosphorus removal sludge by electrodialysis membrane bioreactor.

PubMed

Geng, Yi-Kun; Wang, Yunkun; Pan, Xin-Rong; Sheng, Guo-Ping

2018-01-01

In this study, a novel electrodialysis membrane bioreactor was used for EBPR sludge treatment for energy and phosphorus resource recovery simultaneously. After 30days stable voltage outputting, the maximum power density reached 0.32W/m 3 . Over 90% of phosphorus in EBPR sludge was released while about 50% of phosphorus was concentrated to 4mmol/L as relatively pure phosphate solution. Nitrogen could be removed from EBPR sludge by desalination and denitrification processes. This study provides an optimized way treating sludge for energy production and in situ phosphorus recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

NASA Astrophysics Data System (ADS)

Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

2016-02-01

Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology.

Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

PubMed Central

Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

2016-01-01

Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology. PMID:26830464

Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge.

PubMed

Saliba, Pollyane Diniz; von Sperling, Marcos

2017-10-01

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Optimizing chemical conditioning for odour removal of undigested sewage sludge in drying processes.

PubMed

Vega, Esther; Monclús, Hèctor; Gonzalez-Olmos, Rafael; Martin, Maria J

2015-03-01

Emission of odours during the thermal drying in sludge handling processes is one of the main sources of odour problems in wastewater treatment plants. The objective of this work was to assess the use of the response surface methodology as a technique to optimize the chemical conditioning process of undigested sewage sludges, in order to improve the dewaterability, and to reduce the odour emissions during the thermal drying of the sludge. Synergistic effects between inorganic conditioners (iron chloride and calcium oxide) were observed in terms of sulphur emissions and odour reduction. The developed quadratic models indicated that optimizing the conditioners dosage is possible to increase a 70% the dewaterability, reducing a 50% and 54% the emission of odour and volatile sulphur compounds respectively. The optimization of the conditioning process was validated experimentally. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dynamic modeling of sludge compaction and consolidation processes in wastewater secondary settling tanks.

PubMed

Abusam, A; Keesman, K J

2009-01-01

The double exponential settling model is the widely accepted model for wastewater secondary settling tanks. However, this model does not estimate accurately solids concentrations in the settler underflow stream, mainly because sludge compression and consolidation processes are not considered. In activated sludge systems, accurate estimation of the solids in the underflow stream will facilitate the calibration process and can lead to correct estimates of particularly kinetic parameters related to biomass growth. Using principles of compaction and consolidation, as in soil mechanics, a dynamic model of the sludge consolidation processes taking place in the secondary settling tanks is developed and incorporated to the commonly used double exponential settling model. The modified double exponential model is calibrated and validated using data obtained from a full-scale wastewater treatment plant. Good agreement between predicted and measured data confirmed the validity of the modified model.

Mass flows of perfluorinated compounds (PFCs) in central wastewater treatment plants of industrial zones in Thailand.

PubMed

Kunacheva, Chinagarn; Tanaka, Shuhei; Fujii, Shigeo; Boontanon, Suwanna Kitpati; Musirat, Chanatip; Wongwattana, Thana; Shivakoti, Binaya Raj

2011-04-01

Perfluorinated compounds (PFCs) are fully fluorinated organic compounds, which have been used in many industrial processes and have been detected in wastewater and sludge from municipal wastewater treatment plants (WWTPs) around the world. This study focused on the occurrences of PFCs and PFCs mass flows in the industrial wastewater treatment plants, which reported to be the important sources of PFCs. Surveys were conducted in central wastewater treatment plant in two industrial zones in Thailand. Samples were collected from influent, aeration tank, secondary clarifier effluent, effluent and sludge. The major purpose of this field study was to identify PFCs occurrences and mass flow during industrial WWTP. Solid-phase extraction (SPE) coupled with HPLC-ESI-MS/MS were used for the analysis. Total 10 PFCs including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluoropropanoic acid (PFPA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonate (PFHxS), perfluoronanoic acid (PFNA), perfluordecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA) were measured to identify their occurrences. PFCs were detected in both liquid and solid phase in most samples. The exceptionally high level of PFCs was detected in the treatment plant of IZ1 and IZ2 ranging between 662-847ngL(-1) and 674-1383ngL(-1), respectively, which greater than PFCs found in most domestic wastewater. Due to PFCs non-biodegradable property, both WWTPs were found ineffective in removing PFCs using activated sludge processes. Bio-accumulation in sludge could be the major removal mechanism of PFCs in the process. The increasing amount of PFCs after activated sludge processes were identified which could be due to the degradation of PFCs precursors. PFCs concentration found in the effluent were very high comparing to those in river water of the area. Industrial activity could be the one of major sources of PFCs contamination in the water environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hybrid activated sludge/biofilm process for the treatment of municipal wastewater in a cold climate region: a case study.

PubMed

Di Trapani, Daniele; Christensso, Magnus; Odegaard, Hallvard

2011-01-01

A hybrid activated sludge/biofilm process was investigated for wastewater treatment in a cold climate region. This process, which contains both suspended biomass and biofilm, usually referred as IFAS process, is created by introducing plastic elements as biofilm carrier media into a conventional activated sludge reactor. In the present study, a hybrid process, composed of an activated sludge and a moving bed biofilm reactor was used. The aim of this paper has been to investigate the performances of a hybrid process, and in particular to gain insight the nitrification process, when operated at relatively low MLSS SRT and low temperatures. The results of a pilot-scale study carried out at the Department of Hydraulic and Environmental Engineering at the Norwegian University of Science and Technology in Trondheim are presented. The experimental campaign was divided into two periods. The pilot plant was first operated with a constant HRT of 4.5 hours, while in the second period the influent flow was increased so that HRT was 3.5 hours. The average temperature was near 11.5°C in the overall experimental campaign. The average mixed liquor SRT was 5.7 days. Batch tests on both carriers and suspended biomass were performed in order to evaluate the nitrification rate of the two different biomasses. The results demonstrated that this kind of reactor can efficiently be used for the upgrading of conventional activated sludge plant for achieving year-round nitrification, also in presence of low temperatures, and without the need of additional volumes.

Occurrence of pharmaceuticals in a municipal wastewater treatment plant: mass balance and removal processes.

PubMed

Gao, Pin; Ding, Yunjie; Li, Hui; Xagoraraki, Irene

2012-06-01

Occurrence and removal efficiencies of fifteen pharmaceuticals were investigated in a conventional municipal wastewater treatment plant in Michigan. Concentrations of these pharmaceuticals were determined in both wastewater and sludge phases by a high-performance liquid chromatograph coupled to a tandem mass spectrometer. Detailed mass balance analysis was conducted during the whole treatment process to evaluate the contributing processes for pharmaceutical removal. Among the pharmaceuticals studied, demeclocycline, sulfamerazine, erythromycin and tylosin were not detected in the wastewater treatment plant influent. Other target pharmaceuticals detected in wastewater were also found in the corresponding sludge phase. The removal efficiencies of chlortetracycline, tetracycline, sulfamerazine, acetaminophen and caffeine were >99%, while doxycycline, oxytetracycline, sulfadiazine and lincomycin exhibited relatively lower removal efficiencies (e.g., <50%). For sulfamethoxazole, the removal efficiency was approximately 90%. Carbamazepine manifested a net increase of mass, i.e. 41% more than the input from the influent. Based on the mass balance analysis, biotransformation is believed to be the predominant process responsible for the removal of pharmaceuticals (22% to 99%), whereas contribution of sorption to sludge was relatively insignificant (7%) for the investigated pharmaceuticals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced power generation and energy conversion of sewage sludge by CEA-microbial fuel cells.

PubMed

Abourached, Carole; Lesnik, Keaton Larson; Liu, Hong

2014-08-01

The production of methane from sewage sludge through the use of anaerobic digestion has been able to effectively offset energy costs for wastewater treatment. However, significant energy reserves are left unrecovered and effluent standards are not met necessitating secondary processes such as aeration. In the current study a novel cloth-electrode assembly microbial fuel cell (CEA-MFC) was used to generate electricity from sewage sludge. Fermentation pretreatment of the sludge effectively increased the COD of the supernatant and improved reactor performance. Using the CEA-MFC design, a maximum power density of 1200 mW m(-2) was reached after a fermentation pre-treatment time of 96 h. This power density represents a 275% increase over those previously observed in MFC systems. Results indicate continued improvements are possible and MFCs may be a viable modification to existing wastewater treatment infrastructure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhanced treatment of waste frying oil in an activated sludge system by addition of crude rhamnolipid solution.

PubMed

Zhang, Hongzi; Xiang, Hai; Zhang, Guoliang; Cao, Xia; Meng, Qing

2009-08-15

The presence of high-strength oil and grease (O&G) in wastewater poses serious challenges for environment. Addition of surfactant into the activated sludge bioreactor is feasible in reducing high concentrations of O&G via enhancing its bioavailability. In this paper, an aqueous biosurfactant solution of rhamnolipid as a cell-free culture broth of Pseudomonas aeruginosa zju.um1 was added into a batch of aerobic activated sludge system for treatment of the waste frying oil. This treatment was conducted on both bench and pilot-scales, whereas the removal efficiency of frying oil was determined by analyzing the residue concentration of O&G and chemical oxygen demand (COD). In the presence of varying concentrations of rhamnolipid from 22.5 mg/L to 90 mg/L, aerobic treatment for 30 h was enough to remove over 93% of O&G while this biodegradability was only 10% in the control system with the absence of rhamnolipids. The equivalent biodegradability was similarly obtained on COD under addition of rhamnolipid. Compared with bench studies, a higher treatment efficiency with the presence of rhamnolipids was achieved on a pilot-scale of activated sludge system, in which a short time of 12h was required for removing approximately 95% of O&G while the control treatment attained a low efficiency of 17%. Finally, foaming and biodegradability of rhamnolipids in activated sludge system were further examined in the whole treatment process. It seems that the addition of rhamnolipid-containing culture broth showed great potential for treatment of oily wastewater by activated sludge.

Oil recovery from petroleum sludge through ultrasonic assisted solvent extraction.

PubMed

Hu, Guangji; Li, Jianbing; Huang, Shuhui; Li, Yubao

2016-09-18

The effect of ultrasonic assisted extraction (UAE) process on oil recovery from refinery oily sludge was examined in this study. Two types of UAE treatment including UAE probe (UAEP) system and UAE bath (UAEB) system were investigated. Their oil recovery efficiencies were compared to that of mechanical shaking extraction (MSE). Three solvents including cyclohexane (CHX), ethyl acetate (EA), and methyl ethyl ketone (MEK) were examined as the extraction solvents. The influence of experimental factors on oil and solvent recovery was investigated using an orthogonal experimental design. Results indicated that solvent type, solvent-to-sludge (S/S) ratio, and treatment duration could have significant effects on oil recovery in UAE treatment. Under the optimum conditions, UAEP treatment can obtain an oil recovery of 68.8% within 20 s, which was higher than that (i.e., 62.0%) by MSE treatment after 60 min' extraction. UAEB treatment can also obtain a promising oil recovery within shorter extraction duration (i.e., 15 min) than MSE. UAE was thus illustrated as an effective and improved approach for oily sludge recycling.

Transformation of PVP coated silver nanoparticles in a simulated wastewater treatment process and the effect on microbial communities

PubMed Central

2013-01-01

Background Manufactured silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in consumer goods and consequently their concentrations in wastewater and hence wastewater treatment plants are predicted to increase. We investigated the fate of AgNPs in sludge that was subjected to aerobic and anaerobic treatment and the impact of AgNPs on microbial processes and communities. The initial identification of AgNPs in sludge was carried out using transmission electron microscopy (TEM) with energy dispersive X-ray (EDX) analysis. The solid phase speciation of silver in sludge and wastewater influent was then examined using X-ray absorption spectroscopy (XAS). The effects of transformed AgNPs (mainly Ag-S phases) on nitrification, wastewater microbial populations and, for the first time, methanogenesis was investigated. Results Sequencing batch reactor experiments and anaerobic batch tests, both demonstrated that nitrification rate and methane production were not affected by the addition of AgNPs [at 2.5 mg Ag L-1 (4.9 g L-1 total suspended solids, TSS) and 183.6 mg Ag kg -1 (2.9 g kg-1 total solids, TS), respectively]. The low toxicity is most likely due to AgNP sulfidation. XAS analysis showed that sulfur bonded Ag was the dominant Ag species in both aerobic (activated sludge) and anaerobic sludge. In AgNP and AgNO3 spiked aerobic sludge, metallic Ag was detected (~15%). However, after anaerobic digestion, Ag(0) was not detected by XAS analysis. Dominant wastewater microbial populations were not affected by AgNPs as determined by DNA extraction and pyrotag sequencing. However, there was a shift in niche populations in both aerobic and anaerobic sludge, with a shift in AgNP treated sludge compared with controls. This is the first time that the impact of transformed AgNPs (mainly Ag-S phases) on anaerobic digestion has been reported. Conclusions Silver NPs were transformed to Ag-S phases during activated sludge treatment (prior to anaerobic digestion). Transformed AgNPs, at predicted future Ag wastewater concentrations, did not affect nitrification or methanogenesis. Consequently, AgNPs are very unlikely to affect the efficient functioning of wastewater treatment plants. However, AgNPs may negatively affect sub-dominant wastewater microbial communities. PMID:23497481

[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].

PubMed

Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

2011-07-01

To observe the bioleaching effect on sewage sludge dewaterability, three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume. Subsequently, the bioleached sludge was dewatered by using chamber filter press. The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1: 15 mixing ratio of bioleached sludge to raw sludge. The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial -134 mV to finial 507 mV. The specific resistance to filtration (SRF) of the tested sludge was decreased from original 1.00 x 10(13) m/kg to final 0.09 x 10(13) m/kg after bioleaching. For the subsequent two batch trials, the bioleaching process can be finished in 40 hours and 46 hours, respectively. Likewise, sludge SRF is also significantly decreased to 0.19 x 10(13) m/kg and 0.36 x 10(13) m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1:1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd, and 3rd batch experiments, respectively. The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours. It is found that the moisture of dewatered sludge cake can be reduced to 58%, and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor. In addition, it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%, but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process. Therefore, dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above. Therefore, bioleaching technique is of great engineering application for the treatment of sewage sludge.

Co-digestion of domestic kitchen waste and night soil sludge in a full-scale sludge treatment plant.

PubMed

Yoneyama, Y; Takeno, K

2002-01-01

A study was made on the domestic kitchen waste and night soil treatment performance of a full-scale sludge treatment plant. The sludge treatment at this plant was by thermophilic methane fermentation. The initial treatment, mesophilic to thermophilic fermentation, was able to be started up within a short time by adjusting the amount of influent waste. Thermophilic methane fermentation was carried out for five months (May-October) and the performance under a mean residual time of 22 days indicated a VTS decomposition of 42%, gas generation of 54-1,610 m3/day (average: 755 m3/day), and a mean methane concentration of 60%. The methane gas was used to generate power in the plant and the amount of power generated by methane gas was highest in October (average of 1,200 kWh/day). This was equivalent to about 7% of the power consumed at the entire sludge treatment plant. The BOD/NH4-N of the activated sludge influent water was lower, compared to a case where there is no recycle flow, due to the recycle flow from the methane fermentation process. There was, therefore, a tendency for an increase in the amount of methanol charged into the secondary denitrification tank. However, the quality of the effluent was satisfactory (BOD< 10 mg/L, SS< 5 mg/L, and T-N< 25 mg/L). Study results indicated that it was possible to implement a full-scale plant for recovering organic waste.

System evaluation and microbial analysis of a sulfur cycle-based wastewater treatment process for Co-treatment of simple wet flue gas desulfurization wastes with freshwater sewage.

PubMed

Qian, Jin; Liu, Rulong; Wei, Li; Lu, Hui; Chen, Guang-Hao

2015-09-01

A sulfur cycle-based wastewater treatment process, namely the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated process (SANI(®) process) has been recently developed for organics and nitrogen removal with 90% sludge minimization and 35% energy reduction in the biological treatment of saline sewage from seawater toilet flushing practice in Hong Kong. In this study, sulfate- and sulfite-rich wastes from simple wet flue gas desulfurization (WFGD) were considered as a potential low-cost sulfur source to achieve beneficial co-treatment with non-saline (freshwater) sewage in continental areas, through a Mixed Denitrification (MD)-SANI process trialed with synthetic mixture of simple WFGD wastes and freshwater sewage. The system showed 80% COD removal efficiency (specific COD removal rate of 0.26 kg COD/kg VSS/d) at an optimal pH of 7.5 and complete denitrification through MD (specific nitrogen removal rate of 0.33 kg N/kg VSS/d). Among the electron donors in MD, organics and thiosulfate could induce a much higher denitrifying activity than sulfide in terms of both NO3(-) reduction and NO2(-) reduction, suggesting a much higher nitrogen removal rate in organics-, thiosulfate- and sulfide-based MD in MD-SANI compared to sulfide alone-based autotrophic denitrification in conventional SANI(®). Diverse sulfate/sulfite-reducing bacteria (SRB) genera dominated in the bacterial community of sulfate/sulfite-reducing up-flow sludge bed (SRUSB) sludge without methane producing bacteria detected. Desulfomicrobium-like species possibly for sulfite reduction and Desulfobulbus-like species possibly for sulfate reduction are the two dominant groups with respective abundance of 24.03 and 14.91% in the SRB genera. Diverse denitrifying genera were identified in the bacterial community of anoxic up-flow sludge bed (AnUSB) sludge and the Thauera- and Thiobacillus-like species were the major taxa. These results well explained the successful operation of the lab-scale MD-SANI process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recovery opportunities for metals and energy from sewage sludges.

PubMed

Mulchandani, Anjali; Westerhoff, Paul

2016-09-01

Limitations on current wastewater treatment plant (WWTP) biological processes and solids disposal options present opportunities to implement novel technologies that convert WWTPs into resource recovery facilities. This review considered replacing or augmenting extensive dewatering, anaerobic digestion, and off-site disposal with new thermo-chemical and liquid extraction processes. These technologies may better recover energy and metals while inactivating pathogens and destroying organic pollutants. Because limited direct comparisons between different sludge types exist in the literature for hydrothermal liquefaction, this study augments the findings with experimental data. These experiments demonstrated 50% reduction in sludge mass, with 30% of liquefaction products converted to bio-oil and most metals sequestered within a small mass of solid bio-char residue. Finally, each technology's contribution to the three sustainability pillars is investigated. Although limiting hazardous materials reintroduction to the environment may increase economic cost of sludge treatment, it is balanced by cleaner environment and valuable resource benefits for society. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of deflocculation on the efficiency of disperser induced dairy waste activated sludge disintegration and treatment cost.

PubMed

Devi, T Poornima; Ebenezer, A Vimala; Kumar, S Adish; Kaliappan, S; Banu, J Rajesh

2014-09-01

Excess sludge disintegration by energy intensive processes like mechanical pretreatment is considered to be high in cost. In this study, an attempt has been made to disintegrate excess sludge by disperser in a cost effective manner by deflocculating the sludge using sodium dodecyl sulphate (SDS) at a concentration of 0.04 g/g SS. The disperser pretreatment was effective at a specific energy input of 5013 kJ/kg TS where deflocculated sludge showed higher chemical oxygen demand solubilisation and suspended solids reduction of 26% and 22.9% than flocculated sludge and was found to be 18.8% and 18.6% for former and latter respectively. Higher accumulation of volatile fatty acid (700 mg/L) in deflocculated sludge indicates better hydrolysis of sludge by proposed method. The anaerobic biodegradability resulted in higher biogas production potential of 0.522 L/(g VS) for deflocculated sludge. Cost analysis of the study showed 43% net energy saving in deflocculated sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units.

PubMed

Lou, Jie-Chung; Lin, Yung-Chang

2008-02-01

Wastewater reuse can significantly reduce environmental pollution and save the water sources. The study selected Cheng-Ching Lake water treatment plant in southern Taiwan to discuss the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units. The treatment units of this plant include wastewater basin, sedimentation basin, sludge thickener and sludge dewatering facility. In this study, the treatment efficiency of SS and turbidity were 48.35-99.68% and 24.15-99.36%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH(3)-N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH(3)-N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible.

Comparative study of wastewater treatment and nutrient recycle via activated sludge, microalgae and combination systems.

PubMed

Wang, Liang; Liu, Jinli; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

2016-07-01

Algal-bacterial synergistic cultivation could be an optional wastewater treatment technology in temperate areas. In this study, a locally screened vigorous Chlorella strain was characterized and then it was used in a comparative study of wastewater treatment and nutrient recycle assessment via activated sludge (AS), microalgae and their combination systems. Chlorella sp. cultured with AS in light showed the best performance, in which case the removal efficiencies of COD, NH3-N and TP were 87.3%, 99.2% and 83.9%, respectively, within a short period of 1day. Algal-bacterial combination in light had the best settleability. Chlorella sp. contained biomass, could be processed to feed, fertilizer or fuel due to the improved quality (higher C/H/N) compared with sludge. PCR-DGGE analysis shows that two types of rhizobacteria, namely, Pseudomonas putida and Flavobacterium hauense were enriched in sludge when cultured with algae in light, serving as the basics for artificial consortium construction for improved wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

A review of the technological solutions for the treatment of oily sludges from petroleum refineries.

PubMed

da Silva, Leonardo Jordão; Alves, Flávia Chaves; de França, Francisca Pessôa

2012-10-01

The activities of the oil industry have several impacts on the environment due to the large amounts of oily wastes that are generated. The oily sludges are a semi-solid material composed by a mixture of clay, silica and iron oxides contaminated with oil, produced water and the chemicals used in the production of oil. Nowadays both the treatment and management of these waste materials is essential to promote sustainable management of exploration and exploitation of natural resources. Biological, physical and chemical processes can be used to reduce environmental contamination by petroleum hydrocarbons to acceptable levels. The choice of treatment method depends on the physical and chemical properties of the waste as well as the availability of facilities to process these wastes. Literature provides some operations for treatment of oily sludges, such as landfilling, incineration, co-processing in clinkerization furnaces, microwave liquefaction, centrifugation, destructive distillation, thermal plasma, low-temperature conversion, incorporation in ceramic materials, development of impermeable materials, encapsulation and biodegradation in land farming, biopiles and bioreactors. The management of the technology to be applied for the treatment of oily wastes is essential to promote proper environmental management, and provide alternative methods to reduce, reuse and recycle the wastes.

Application of Ozone MBBR Process in Refinery Wastewater Treatment

NASA Astrophysics Data System (ADS)

Lin, Wang

2018-01-01

Moving Bed Biofilm Reactor (MBBR) is a kind of sewage treatment technology based on fluidized bed. At the same time, it can also be regarded as an efficient new reactor between active sludge method and the biological membrane method. The application of ozone MBBR process in refinery wastewater treatment is mainly studied. The key point is to design the ozone +MBBR combined process based on MBBR process. The ozone +MBBR process is used to analyze the treatment of concentrated water COD discharged from the refinery wastewater treatment plant. The experimental results show that the average removal rate of COD is 46.0%~67.3% in the treatment of reverse osmosis concentrated water by ozone MBBR process, and the effluent can meet the relevant standard requirements. Compared with the traditional process, the ozone MBBR process is more flexible. The investment of this process is mainly ozone generator, blower and so on. The prices of these items are relatively inexpensive, and these costs can be offset by the excess investment in traditional activated sludge processes. At the same time, ozone MBBR process has obvious advantages in water quality, stability and other aspects.

Partial nitritation of raw anaerobic sludge digester liquor by swim-bed and swim-bed activated sludge processes and comparison of their sludge characteristics.

PubMed

Qiao, Sen; Kawakubo, Yuki; Koyama, Toichiro; Furukawa, Kenji

2008-11-01

This study evaluated performance of swim-bed (SB) reactors packed with a novel acrylic fiber carrier (BF) and swim-bed activated sludge (SBAS) reactor for partial nitritation of anaerobic sludge digester liquor from a municipal wastewater treatment plant. Comparison of characteristics of sludge obtained from both the reactors was also made. The average conversion rates of ammonium to nitrite were 52.3% and 40.0% under relatively high nitrogen loading rates over 3.0 kg-N/m(3)/d, respectively in two reactors. The average BOD(5) removal efficiencies were 74.3% and 64.4%, respectively in the two reactors. The size of the sludge pellets taken from SB and SBAS reactors was found to be approximately three times (229 mum versus 88 mum) of that of the seed sludge. This sludge also had relatively high extracellular proteins levels indicating better sludge settling capability as compared to the sludge taken from SBAS reactor. Although the effluent nitrite/ammonium ratios had fluctuated in both reactor in some extent, the low dissolved oxygen concentration (average of 2.5 versus 0.35 mg/l), low suspended solids (average of 33.3 versus 33.5 mg/l), and about 50% ammonium conversion to nitrite demonstrated the application potential of anammox process for nitrogen removal.

Removal of native coliphages and coliform bacteria from municipal wastewater by various wastewater treatment processes: implications to water reuse.

PubMed

Zhang, K; Farahbakhsh, K

2007-06-01

The efficacy of a conventional activated sludge wastewater treatment process and the membrane bioreactor technology in removing microbial pathogens was investigated. Total and fecal coliforms and somatic and F-specific coliphages were used as indicators of pathogenic bacteria and viruses. Up to 5.7 logs removal of coliforms and 5.5 logs of coliphages were observed in the conventional treatment process with advanced tertiary treatment. Addition of chemical coagulants seemed to improve the efficacy of primary and secondary treatment for microorganism removal. Complete removal of fecal coliforms and up to 5.8 logs removal of coliphages was observed in the MBR system. It was shown that the MBR system was capable of high removal of coliphages despite the variation in feed coliphage concentrations. The results of this study indicated that the MBR system can achieve better microbial removal in far fewer steps than the conventional activated sludge process with advanced tertiary treatment. The final effluent from either treatment processes can be potentially reused.

Industrial activated sludge exhibit unique bacterial community composition at high taxonomic ranks.

PubMed

Ibarbalz, Federico M; Figuerola, Eva L M; Erijman, Leonardo

2013-07-01

Biological degradation of domestic and industrial wastewater by activated sludge depends on a common process of separation of the diverse self-assembled and self-sustained microbial flocs from the treated wastewater. Previous surveys of bacterial communities indicated the presence of a common core of bacterial phyla in municipal activated sludge, an observation consistent with the concept of ecological coherence of high taxonomic ranks. The aim of this work was to test whether this critical feature brings about a common pattern of abundance distribution of high bacterial taxa in industrial and domestic activated sludge, and to relate the bacterial community structure of industrial activated sludge with relevant operational parameters. We have applied 454 pyrosequencing of 16S rRNA genes to evaluate bacterial communities in full-scale biological wastewater treatment plants sampled at different times, including seven systems treating wastewater from different industries and one plant that treats domestic wastewater, and compared our datasets with the data from municipal wastewater treatment plants obtained by three different laboratories. We observed that each industrial activated sludge system exhibited a unique bacterial community composition, which is clearly distinct from the common profile of bacterial phyla or classes observed in municipal plants. The influence of process parameters on the bacterial community structure was evaluated using constrained analysis of principal coordinates (CAP). Part of the differences in the bacterial community structure between industrial wastewater treatment systems were explained by dissolved oxygen and pH. Despite the ecological relevance of floc formation for the assembly of bacterial communities in activated sludge, the wastewater characteristics are likely to be the major determinant that drives bacterial composition at high taxonomic ranks. Copyright © 2013 Elsevier Ltd. All rights reserved.

A decision support tool for selecting the optimal sewage sludge treatment.

PubMed

Turunen, Ville; Sorvari, Jaana; Mikola, Anna

2018-02-01

Sewage sludge contains significant amounts of resources, such as nutrients and organic matter. At the same time, the organic contaminants (OC) found in sewage sludge are of growing concern. Consequently, in many European countries incineration is currently favored over recycling in agriculture. This study presents a Multi-Attribute Value Theory (MAVT)-based decision support tool (DST) for facilitating sludge treatment decisions. Essential decision criteria were recognized and prioritized, i.e., weighted, by experts from water utilities. Since the fate of organic contaminants was in focus, a simple scoring method was developed to take into account their environmental risks. The final DST assigns each sludge treatment method a preference score expressing its superiority compared to alternative methods. The DST was validated by testing it with data from two Finnish municipal wastewater treatment plants (WWTP). The validation results of the first case study preferred sludge pyrolysis (preference score: 0.629) to other alternatives: composting and incineration (score 0.580, and 0.484 respectively). The preference scores were influenced by WWTP dependent factors, i.e., the operating environment and the weighting of the criteria. A lack of data emerged as the main practical limitation. Therefore, not all of the relevant criteria could be included in the value tree. More data are needed on the effects of treatment methods on the availability of nutrients, the quality of organic matter and sludge-borne OCs. Despite these shortcomings, the DST proved useful and adaptable in decision-making. It can also help achieve a more transparent, understandable and comprehensive decision-making process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of sewage sludge treatment using air plasma assisted gasification.

PubMed

Striūgas, Nerijus; Valinčius, Vitas; Pedišius, Nerijus; Poškas, Robertas; Zakarauskas, Kęstutis

2017-06-01

This study presents an experimental investigation of downdraft gasification process coupled with a secondary thermal plasma reactor in order to perform experimental investigations of sewage sludge gasification, and compare process parameters running the system with and without the secondary thermal plasma reactor. The experimental investigation were performed with non-pelletized mixture of dried sewage sludge and wood pellets. To estimate the process performance, the composition of the producer gas, tars, particle matter, producer gas and char yield were measured at the exit of the gasification and plasma reactor. The research revealed the distribution of selected metals and chlorine in the process products and examined a possible formation of hexachlorobenzene. It determined that the plasma assisted processing of gaseous products changes the composition of the tars and the producer gas, mostly by destruction of hydrocarbon species, such as methane, acetylene, ethane or propane. Plasma processing of the producer gas reduces their calorific value but increases the gas yield and the total produced energy amount. The presented technology demonstrated capability both for applying to reduce the accumulation of the sewage sludge and production of substitute gas for drying of sewage sludge and electrical power. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sampling and analysis plan for sludge located on the floor and in the pits of the 105-K basins

DOE Office of Scientific and Technical Information (OSTI.GOV)

BAKER, R.B.

1998-11-20

This Sampling and Analysis Plan (SAP) provides direction for the sampling of the sludge found on the floor and in the remote pits of the 105-K Basins to provide: (1) basic data for the sludges that have not been characterized to-date and (2) representative Sludge material for process tests to be made by the SNF Project/K Basins sludge treatment process subproject. The sampling equipment developed will remove representative samples of the radioactive sludge from underwater at the K Basins, depositing them in shielded containers for transport to the Hanford Site laboratories. Included in the present document is the basic backgroundmore » logic for selection of the samples to meet the requirements established in the Data Quality Objectives (DQO), HNF-2033, for this sampling activity. The present document also includes the laboratory analyses, methods, procedures, and reporting that will be required to meet the DQO.« less

Chromium fractionation and plant availability in tannery-sludge amended soil

NASA Astrophysics Data System (ADS)

Allué, Josep; Moya Garcés, Alba; Bech, Jaume; Barceló, Juan; Poschenrieder, Charlotte

2013-04-01

The leather industry represents an important economic sector in both developed and developing countries. Chromium tanning is the major process used to obtain high quality leather. Within the REACH regulation the use of Cr, especially CrVI, in the tanning process is under discussion in Europe. High Cr concentration in shoes and other Cr-tanned leather products can cause contact dermatitis in sensitive population. Moreover, the high Cr concentration is the major limiting factor for the use of tannery sludge as a source of organic matter in agricultural soils. Interest in Cr, however is not limited to its potential toxic effects. Chromium III is used as a dietary supplement because there are reports, but also controversy, about the positive effects of Cr III in glucose tolerance and type-2 diabetes. Adequate intake levels for Cr by the diet have been established between 25 and 35 µg/day for adult females and males, respectively. Sufficient supply of Cr III by the diet is preferable to the use of CrIII-salt based dietary supplements. The objective of the present work was to investigate whether Cr from tannery sludge-amended soil is available to Trigonella foenum-graecum plants, a plant used both as a spice and as a medicinal herb, because of its hypoglucemic effects. For this purpose clay loam soil (pH 7.8) was sieved (2mm) and thoroughly mixed with tannery sludge from a depuration station (Igualadina Depuració i Recuperació S.L., Igualada, Barcelona, Spain). The sludge had a Cr concentration of 6,034mg kg-1 and a 0.73 % of NH4-nitrogen. All the Cr was in the form of CrIII. Three treatments were disposed. Control soil receiving no sludge, a 60 mg kg-1 Cr treatment (10 g fresh sludge kg-1 soil) and a 120 mg kg-1 Cr treatment (20 g fresh sludge kg-1 soil). Control soil and the soil treated with 10g kg-1 sludge received NPK fertilizer in the form of ammonium sulfate, superfosfate, and KCl to rise the N,P, and K concentrations to similar levels to those achieved in the soils with the highest sludge dose (20 g kg-1). Soils from the different treatments were potted (5 L) and planted with Trigonella foenum graecum seeds (1 plant per pot). Plants were harvested in the vegetative stage and processed for tissue analysis of Cr, Fe, Zn and Pb. A sequential extraction procedure was applied to the soil for getting insight into the operationally defined soil fractions that incorporate the tannery sludge derived Cr. In any of the treatments Cr was detectable in the exchangeable and easily reducible fractions. In control soils around 10% of soil Cr was in the moderately reducible fraction and the rest in the residual fraction. Contrastingly tannery sludge amended soils incorporated most Cr in the moderately reducible fraction extracted by acid oxalate. This distribution in relation to plant Cr concentrations will be discussed. Acknowledgement: Supported by the Spanish Government (project BFU2010-14873)

More than a decade of experience of landfill leachate treatment with a full-scale anammox plant combining activated sludge and activated carbon biofilm.

PubMed

Azari, Mohammad; Walter, Uwe; Rekers, Volker; Gu, Ji-Dong; Denecke, Martin

2017-05-01

The performance of biological treatment for high ammonium removal from landfill leachate has been demonstrated. The plant was upgraded combining the activated sludge process followed by activated carbon reactor. Based on a long-term analysis of data collected from 2006 to 2015, the average total nitrogen removal efficiency of 94% was achieved for wastewaters with a C: N ratio varying from 1 to 5 kg-COD kg-TN -1 . But without the presence of activated carbon reactor, the average of biological removal efficiency for total nitrogen was only 82% ± 6% for the activated sludge stage. It means that up to 20% of the nitrogen in the influent can only be eliminated by microorganisms attached to granular activated carbon. After upgrades of the plant, the energy efficiency showed a reduction in the specific energy demand from 1.6 to less than 0.2 kWh m -3 . Methanol consumption and sludge production was reduced by 91% and 96%, respectively. Fluorescent in situ Hybridization was used for microbial diversity analysis on floccular sludge and granular biofilm samples. Anaerobic ammonium oxidation (anammox) bacteria and nitrifiers were detected and Candidatus Scalindua was found in two forms of flocs and biofilms. Due to stochastic risk assessment based on the long-term data analysis given in this research, the treatment criteria were achieved and the combination of granular activated carbon biofilm process and activated sludge can be a novel and sought approach to better enrich anammox biomass for full-scale treatment applications to reduce operating costs and promote nutrient removal stability and efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of Autothermal Thermophilic Aerobic Digester Performance for the Stabilization of Municipal Wastewater Sludge.

PubMed

Shokoohi, Reza; Rahmani, Alireza; Asgari, Ghorban; Dargahi, Abdollah; Vaziri, Yaser; Abbasi, Mohammad Attar

2017-01-01

Sludge stabilization process in terms of operational, environmental and economic indexes is the most important stage of treatment and its disposal. This study was aimed to determine the performance of Autothermal Thermophilic Aerobic Digestion (ATAD) system as one of the low-cost and biocompatible methods of sludge treatment. This study has been done using a laboratory scale Autothermal Thermophilic Aerobic Digestion (ATAD). The reactor was consisted of two polyethylene tanks with a final capacity of 100 L for each tank. Both tanks with all fittings were installed on a metal frame. The variables of study were temperature, dissolved oxygen, pH, volatile organic compounds, total solids, COD and the number of Ascaris eggs and fecal coliforms per gram of dry matter of the sludge. The temperature was measured hourly and the pH and dissolved oxygen were measured and controlled twice per day. One-way ANNOVA was applied to analyze reasults. According to the results, the temperature of sludge increased from 11.7-61.2°C by biological reactions. Pathogen organisms were reduced from 80×106 to 503 in number during 72 h. After 6 days pathogen organisms and Ascaris eggs were removed completely. Volatile organic compounds and COD were reduced 42 and 38.3% respectively during the 6 days. It is concluded that the performance of ATAD in removing organic compounds from wastewater sludge were desirable. Resulted sludge from stabilization process were appropriate for use in agriculture as a soil supplement and met the indexes of class A sludge according to EPA's standards (CFR 40 Part 503).

In-situ sludge reduction and carbon reuse in an anoxic/oxic process coupled with hydrocyclone breakage.

PubMed

Xu, Yinxiang; Fang, Yuanyuan; Wang, Zhenhua; Guo, Dan; Liu, Yi; Huang, Yuan; Fu, Pengbo; Jin, Juehui; Wei, Chenwen; Wang, Hualin; Zeng, Tao

2018-05-09

The long-term performance of an anoxic-oxic-hydrocyclone (AOH) process with an in-situ hydrocyclone treatment unit in the mixed liquid return line for sludge reduction and carbon reuse has been observed, in comparison with a conventional anoxic-oxic (AO) process. Three parallel side-stream systems, including one AOH 25 system with a 25-mm hydrocyclone, one AOH 35 system with a 35-mm hydrocyclone and one AO system, were built and fed with real wastewater for a comparative study in a wastewater treatment plant. The results demonstrate that the hydrocyclone in the AOH process was able to break macro-flocs into smaller flocs. And the desorption of the extracellular polymeric substance from return activated sludge (AS) leaded to an average increase of 62.97% and 36.36% in SCOD in the AOH 25 and AOH 35 system, respectively. In addition, shear forces, centrifugal forces of revolution and flocs' rotation in the hydrocyclone were proposed to be the main influence mechanism of hydrocyclone treatment on AS properties. Compared with the AO process, the SCOD concentration in the effluent of the AOH processes presented a decrease of 12.0 mg/L and the TN was reduced by 21.50% owing to the released carbon sources reuse. Moreover, the sludge production was reduced by 36.81% and 35.92% in the AOH 25 and AOH 35 process, respectively. By contrast, the AOH 25 system was better than the AOH 35 system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of bioleaching and electrokinetic remediation processes for removal of heavy metals from wastewater treatment sludge.

PubMed

Xu, Ying; Zhang, Chaosheng; Zhao, Meihua; Rong, Hongwei; Zhang, Kefang; Chen, Qiuli

2017-02-01

Heavy metals prevent the growing amount of sewage sludge from being disposed as fertilizeron land. The electrokinetic remediation and bioleaching technology are the promising methods to remove heavy metals. In recent years, some innovation has been made to achieve better efficiency, including the innovation of processes and agents. This paper reviews the development of the electrokinetic remediation and bioleaching technology and analyses their advantages and limitation, pointing out the need of the future research for the heavy metals-contaminated sewage sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mass flow of antibiotics in a wastewater treatment plant focusing on removal variations due to operational parameters.

PubMed

Marx, Conrad; Günther, Norbert; Schubert, Sara; Oertel, Reinhard; Ahnert, Markus; Krebs, Peter; Kuehn, Volker

2015-12-15

Wastewater treatment plants (WWTPs) are not designed to purposefully eliminate antibiotics and therefore many previous investigations have been carried out to assess their fate in biological wastewater treatment processes. In order to consolidate previous findings regarding influencing factors like the solid and hydraulic retention time an intensive monitoring was carried out in a municipal WWTP in Germany. Over a period of 12months daily samples were taken from the in- and effluent as well as diverse sludge streams. The 14 selected antibiotics and one metabolite cover the following classes: cephalosporins, diaminopyrimidines, fluoroquinolones, lincosamide, macrolides, penicillins, sulfonamides and tetracyclines. Out of the 15 investigated substances, the removal of only clindamycin and ciprofloxacin show significant correlations to SRT, temperature, HRT and nitrogen removal. The dependency of clindamycin's removal could be related to the significant negative removal (i.e. production) of clindamycin in the treatment process and was corrected using the human metabolite clindamycin-sulfoxide. The average elimination was adjusted from -225% to 3% which suggests that clindamycin can be considered as an inert substance during the wastewater treatment process. Based on the presented data, the mass flow analysis revealed that macrolides, clindamycin/clindamycin-sulfoxide and trimethoprim were mainly released with the effluent, while penicillins, cephalosporins as well as sulfamethoxazole were partly degraded in the studied WWTP. Furthermore, levofloxacin and ciprofloxacin are the only antibiotics under investigation with a significant mass fraction bound to primary, excess and digested sludge. Nevertheless, the sludge concentrations are highly inconsistent which leads to questionable results. It remains unclear whether the inconsistencies are due to insufficiencies in sampling and/or analytical determination or if the fluctuations can be considered reasonable for digesters. Hence, future investigations have to address antibiotic's temporal dynamics during the sludge treatment to decide whether or not the widely reported standard deviations of sludge concentrations reflect realistic fluctuations. Copyright © 2015 Elsevier B.V. All rights reserved.

Copper-Sulfate Pentahydrate as a Product of the Waste Sulfuric Acid Solution Treatment

NASA Astrophysics Data System (ADS)

Marković, Radmila; Stevanović, Jasmina; Avramović, Ljiljana; Nedeljković, Dragutin; Jugović, Branimir; Stajić-Trošić, Jasna; Gvozdenović, Milica

2012-12-01

The aim of this study is synthesis of copper-sulfate pentahydrate from the waste sulfuric acid solution-mother liquor generated during the regeneration process of copper bleed solution. Copper is removed from the mother liquor solution in the process of the electrolytic treatment using the insoluble lead anodes alloyed with 6 mass pct of antimony on the industrial-scale equipment. As the result of the decopperization process, copper is removed in the form of the cathode sludge and is precipitated at the bottom of the electrolytic cell. By this procedure, the content of copper could be reduced to the 20 mass pct of the initial value. Chemical characterization of the sludge has shown that it contains about 90 mass pct of copper. During the decopperization process, the very strong poison, arsine, can be formed, and the process is in that case terminated. The copper leaching degree of 82 mass pct is obtained using H2SO4 aqueous solution with the oxygen addition during the cathode sludge chemical treatment at 80 °C ± 5 °C. Obtained copper salt satisfies the requirements of the Serbian Standard for Pesticide, SRPS H.P1. 058. Therefore, the treatment of waste sulfuric acid solutions is of great economic and environmental interest.

Treatment of swine wastewater using chemically modified zeolite and bioflocculant from activated sludge.

PubMed

Guo, Junyuan; Yang, Chunping; Zeng, Guangming

2013-09-01

Sterilization, alkaline-thermal and acid-thermal treatments were applied to activated sludge and the pre-treated sludge was used as raw material for Rhodococcus R3 to produce polymeric substances. After 60 h of fermentation, bioflocculant of 2.7 and 4.2 g L(-1) were produced in sterilized and alkaline-thermal treated sludge as compared to that of 0.9 g L(-1) in acid-thermal treated sludge. Response surface methodology (RSM) was employed to optimize the treatment process of swine wastewater using the composite of bioflocculant and zeolite modified by calcining with MgO. The optimal flocculating conditions were bioflocculant of 24 mg L(-1), modified zeolite of 12 g L(-1), CaCl2 of 16 mg L(-1), pH of 8.3 and contact time of 55 min, and the corresponding removal rates of COD, ammonium and turbidity were 87.9%, 86.9%, and 94.8%. The use of the composite by RSM provides a feasible way to improve the pollutant removal efficiencies and recycle high-level of ammonium from wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Strength Measurements of Archive K Basin Sludge Using a Soil Penetrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delegard, Calvin H.; Schmidt, Andrew J.; Chenault, Jeffrey W.

2011-12-06

Spent fuel radioactive sludge present in the K East and K West spent nuclear fuel storage basins now resides in the KW Basin in six large underwater engineered containers. The sludge will be dispositioned in two phases under the Sludge Treatment Project: (1) hydraulic retrieval into sludge transport and storage containers (STSCs) and transport to interim storage in Central Plateau and (2) retrieval from the STSCs, treatment, and packaging for shipment to the Waste Isolation Pilot Plant. In the years the STSCs are stored, sludge strength is expected to increase through chemical reaction, intergrowth of sludge crystals, and compaction andmore » dewatering by settling. Increased sludge strength can impact the type and operation of the retrieval equipment needed prior to final sludge treatment and packaging. It is important to determine whether water jetting, planned for sludge retrieval from STSCs, will be effective. Shear strength is a property known to correlate with the effectiveness of water jetting. Accordingly, the unconfined compressive strengths (UCS) of archive K Basin sludge samples and sludge blends were measured using a pocket penetrometer modified for hot cell use. Based on known correlations, UCS values can be converted to shear strengths. Twenty-six sludge samples, stored in hot cells for a number of years since last being disturbed, were identified as potential candidates for UCS measurement and valid UCS measurements were made for twelve, each of which was found as moist or water-immersed solids at least 1/2-inch deep. Ten of the twelve samples were relatively weak, having consistencies described as 'very soft' to 'soft'. Two of the twelve samples, KE Pit and KC-4 P250, were strong with 'very stiff' and 'stiff' consistencies described, respectively, as 'can be indented by a thumb nail' or 'can be indented by thumb'. Both of these sludge samples are composites collected from KE Basin floor and Weasel Pit locations. Despite both strong sludges having relatively high iron concentrations, attribution of their high strengths to this factor could not be made with confidence as other measured sludge samples, also from the KE Basin floor and of high iron concentration, were relatively weak. The observed UCS and shear strengths for the two strong sludges were greater than observed in any prior testing of K Basin sludge except for sludge processed at 185 C under hydrothermal conditions.« less

Study on substrate metabolism process of saline waste sludge and its biological hydrogen production potential.

PubMed

Zhang, Zengshuai; Guo, Liang; Li, Qianqian; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

2017-07-01

With the increasing of high saline waste sludge production, the treatment and utilization of saline waste sludge attracted more and more attention. In this study, the biological hydrogen production from saline waste sludge after heating pretreatment was studied. The substrate metabolism process at different salinity condition was analyzed by the changes of soluble chemical oxygen demand (SCOD), carbohydrate and protein in extracellular polymeric substances (EPS), and dissolved organic matters (DOM). The excitation-emission matrix (EEM) with fluorescence regional integration (FRI) was also used to investigate the effect of salinity on EPS and DOM composition during hydrogen fermentation. The highest hydrogen yield of 23.6 mL H 2 /g VSS and hydrogen content of 77.6% were obtained at 0.0% salinity condition. The salinity could influence the hydrogen production and substrate metabolism of waste sludge.

[Ultrasonic sludge treatment and its application on aerobic digestion].

PubMed

Li, Huan; Jin, Yi-ying; Nie, Yong-feng; Li, Lei; Yang, Hai-ying

2007-07-01

In order to enhance the degradation efficiency of waste activated sludge (WAS) in conventional aerobic digestion, various ultrasonic assisted treatment methods were investigated including ultrasonic disintegration of influent sludge, ultrasonic improvement of influent sludge activity and ultrasonic disintegration of return sludge. Firstly the effects of ultrasonic sludge treatment were studied to choose appropriate ultrasonic parameters, and then the experiments of aerobic digestion with different ultrasonic treatments were carried out. The results show that 1.0 W/mL, 10 minutes ultrasonic treatment can increase soluble chemical oxygen demand (SCOD) in the supernatant phase of sludge sample by 5.4 times and decrease total suspended solid (TSS) by 16%; 0.05 W/mL, 10 min ultrasonic treatment can increase the specific oxygen uptake rate (SOUR) of sludge sample by 29%. The two kinds of ultrasonic influent sludge pretreatment can't improve aerobic digestion effectively. Ultrasonic return sludge disintegration can enhance the volatile suspended solid (VSS) degradation ratio by 15%. Furthermore, the settlement performance of digested sludge is still good and the pollutant concentrations of supernatant phase increase slightly. So ultrasonic return sludge disintegration is considered as the most appropriate assisted treatment mode for aerobic digestion.

Mass balance analysis of triclosan, diethyltoluamide, crotamiton and carbamazepine in sewage treatment plants.

PubMed

Nakada, N; Yasojima, M; Okayasu, Y; Komori, K; Suzuki, Y

2010-01-01

The behavior of antibacterial triclosan, insect-repellent diethyltoluamide (DEET), anticonvulsant carbamazepine, and antipruritic crotamiton was investigated at two sewage treatment plants (STPs) to clarify their complete mass balance. Twenty-four-hour flow-proportional composite samples were collected from the influent and effluent of primary and final sedimentation tanks, a biofiltration tank and disinfection tanks. Sludge samples (i.e., activated and excess sludge) and samples of the return flow from the sludge treatment process were collected in the same manner. The analytes in both the dissolved and particulate phases were individually determined by a gas chromatograph equipped with mass spectrometer. Triclosan was dominantly detected in the particulate phase especially in the early stage of treatment (up to 83%) and was efficiently removed (over 90%) in STPs, mainly by sorption to sewage sludge. Limited removal was observed for DEET (55+/-24%), while no significant removal was demonstrated for crotamiton or carbamazepine. The solid-water distribution coefficients (K(d), n=4) for triclosan (log K(d): 3.7-5.1), DEET (1.3-1.9) and crotamiton (1.1-1.6) in the sludge samples are also determined in this study. These findings indicate the limitations of current sewage treatment techniques for the removal of these water-soluble drugs (i.e. DEET, carbamazepine, and crotamiton).

13C-NMR Assessment of the Pattern of Organic Matter Transformation during Domestic Wastewater Treatment by Autothermal Aerobic Digestion (ATAD)

PubMed Central

Piterina, Anna V.; Barlett, John; Pembroke, J. Tony

2009-01-01

The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised via solid-state 13C-NMR CP-MAS. Major indexes such as aromaticity, hydrophobicity and alkyl/O-alkyl ratios calculated for the ATAD processed biosolids were compared by means of these values to corresponding indexes reported for sludges of different origin such as manures, soil organic matter and certain types of compost. Given that this is the first time that these techniques have been applied to ATAD sludge, the data indicates that long-chain aliphatics are easily utilized by the microbial populations as substrates for metabolic activities at all stages of aerobic digestion and serve as a key substrate for the temperature increase, which in turn results in sludge sterilization. The ATAD biosolids following treatment had a prevalence of O-alkyl domains, a low aromaticity index (10.4%) and an alkyl/O-alkyl ratio of 0.48 while the hydrophobicity index of the sludge decreased from 1.12 to 0.62 during the treatment. These results have important implications for the evolution of new ATAD modalities particularly in relation to dewatering and the future use of ATAD processed biosolids as a fertilizer, particularly with respect to hydrological impacts on the soil behaviour. PMID:19742161

C-NMR assessment of the pattern of organic matter transformation during domestic wastewater treatment by autothermal aerobic digestion (ATAD).

PubMed

Piterina, Anna V; Barlett, John; Pembroke, J Tony

2009-08-01

The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised via solid-state (13)C-NMR CP-MAS. Major indexes such as aromaticity, hydrophobicity and alkyl/O-alkyl ratios calculated for the ATAD processed biosolids were compared by means of these values to corresponding indexes reported for sludges of different origin such as manures, soil organic matter and certain types of compost. Given that this is the first time that these techniques have been applied to ATAD sludge, the data indicates that long-chain aliphatics are easily utilized by the microbial populations as substrates for metabolic activities at all stages of aerobic digestion and serve as a key substrate for the temperature increase, which in turn results in sludge sterilization. The ATAD biosolids following treatment had a prevalence of O-alkyl domains, a low aromaticity index (10.4%) and an alkyl/O-alkyl ratio of 0.48 while the hydrophobicity index of the sludge decreased from 1.12 to 0.62 during the treatment. These results have important implications for the evolution of new ATAD modalities particularly in relation to dewatering and the future use of ATAD processed biosolids as a fertilizer, particularly with respect to hydrological impacts on the soil behaviour.

Exploration on the technology for ozone reduction in urban sewage treatment

NASA Astrophysics Data System (ADS)

Yang, Min; Sun, Yi; Han, Zhicheng; Liu, Jun

2017-05-01

With the rapid development of China’s economy, urban water consumption is increasing. However, sewage treatment plants will produce large amounts of sludge after treatment of sewage. Generally, and the sludge treatment costs are relatively high. Therefore, the problem about how to deal with the sewage sludge becomes the hot issues. Municipal waste water treatment plant produces a lot of sludge. This paper summarized the abroad study of ozonation minimization technology. Introduction and discussion were made on the principle of ozonated efficiency of sludge minimization, the efficiency of sludge minimization and the relationship between efficiency and ozone dosage, as well the effect of return sludge ozonated on waste water treatment running and the sludge setting and the dewatering characteristic. The economic estimation was also made on this technology. It’s showed that sludge minimization technology exhibits extensive application foreground.

Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

PubMed

Dumas, C; Perez, S; Paul, E; Lefebvre, X

2010-04-01

The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. Copyright 2009 Elsevier Ltd. All rights reserved.

Sludge thermal oxidation processes: mineral recycling, energy impact, and greenhouse effect gases release.

PubMed

Guibelin, E

2004-01-01

Different treatment routes have been studied for a mixed sludge: the conventional agricultural use is compared with the thermal oxidation processes, including incineration (in gaseous phase) and wet air oxidation (in liquid phase). The interest of a sludge digestion prior to the final treatment has been also considered according to the two major criteria, which are the fossil energy utilisation and the greenhouse effect gases (CO2, CH4, N2O) release. Thermal energy has to be recovered on thermal processes to make these processes environmentally friendly, otherwise their main interest is to extract or destroy micropollutants and pathogens from the carbon cycle. In case of continuous energy recovery, incineration can produce more energy than it consumes. Digestion is especially interesting for agriculture: according to these two schemes, the energy final balance can also be in excess. As to wet air oxidation, it is probably one of the best ways to minimize greenhouse effect gases emission.

Nitrogen removal from the saline sludge liquor by electrochemical denitrification.

PubMed

Xie, Z M; Li, X Y; Chan, K Y

2006-01-01

Sludge liquor from the sludge dewatering process has a high ammonia content. In the present study, a lab-scale electrochemical (EC) system with a pair of Ti electrode plates was used for treating the sludge centrate liquor of digested wastewater sludge with a NH4(+) - N content of around 500 mg/L. The sludge liquor had a high salinity due to seawater being used for toilet flushing in Hong Kong. The results show that the EC process is highly effective for denitrification of the saline sludge liquor. Complete nitrogen removal could be achieved within 1 hr or so. The rate of EC denitrification increased with the current intensity applied. The best current efficiency for nitrogen removal was obtained for a gap distance between the electrodes at 8 mm. Electro-chlorination was considered to be the major mechanism of EC denitrification. The formation of chlorination by-products (CBPs) appeared to be minimal with the total trihalomethanes (THM) detected at a level of 300 microg/L or lower. The power consumption for EC denitrification was around 23 kWh/kg N. Additional electro-flocculation with a pair of iron needle electrodes could enhance the flocculation and subsequent sedimentation of colloidal organics in the sludge liquor, increasing the organic removal from less than 30% to more than 70%. Therefore, the EC process including both electro-denitrification and electro-flocculation can be developed as the most cost-effective method for treatment of the saline sludge liquor.

Optimization of the preparation conditions of ceramic products using drinking water treatment sludges.

PubMed

Zamora, R M Ramirez; Ayala, F Espesel; Garcia, L Chavez; Moreno, A Duran; Schouwenaars, R

2008-11-01

The aim of this work is to optimize, via Response Surface Methodology, the values of the main process parameters for the production of ceramic products using sludges obtained from drinking water treatment in order to valorise them. In the first experimental stage, sludges were collected from a drinking water treatment plant for characterization. In the second stage, trials were carried out to elaborate thin cross-section specimens and fired bricks following an orthogonal central composite design of experiments with three factors (sludge composition, grain size and firing temperature) and five levels. The optimization parameters (Y(1)=shrinking by firing (%), Y(2)=water absorption (%), Y(3)=density (g/cm(3)) and Y(4)=compressive strength (kg/cm(2))) were determined according to standardized analytical methods. Two distinct physicochemical processes were active during firing at different conditions in the experimental design, preventing the determination of a full response surface, which would allow direct optimization of production parameters. Nevertheless, the temperature range for the production of classical red brick was closely delimitated by the results; above this temperature, a lightweight ceramic with surprisingly high strength was produced, opening possibilities for the valorisation of a product with considerably higher added value than what was originally envisioned.

Activated sludge model (ASM) based modelling of membrane bioreactor (MBR) processes: a critical review with special regard to MBR specificities.

PubMed

Fenu, A; Guglielmi, G; Jimenez, J; Spèrandio, M; Saroj, D; Lesjean, B; Brepols, C; Thoeye, C; Nopens, I

2010-08-01

Membrane bioreactors (MBRs) have been increasingly employed for municipal and industrial wastewater treatment in the last decade. The efforts for modelling of such wastewater treatment systems have always targeted either the biological processes (treatment quality target) as well as the various aspects of engineering (cost effective design and operation). The development of Activated Sludge Models (ASM) was an important evolution in the modelling of Conventional Activated Sludge (CAS) processes and their use is now very well established. However, although they were initially developed to describe CAS processes, they have simply been transferred and applied to MBR processes. Recent studies on MBR biological processes have reported several crucial specificities: medium to very high sludge retention times, high mixed liquor concentration, accumulation of soluble microbial products (SMP) rejected by the membrane filtration step, and high aeration rates for scouring purposes. These aspects raise the question as to what extent the ASM framework is applicable to MBR processes. Several studies highlighting some of the aforementioned issues are scattered through the literature. Hence, through a concise and structured overview of the past developments and current state-of-the-art in biological modelling of MBR, this review explores ASM-based modelling applied to MBR processes. The work aims to synthesize previous studies and differentiates between unmodified and modified applications of ASM to MBR. Particular emphasis is placed on influent fractionation, biokinetics, and soluble microbial products (SMPs)/exo-polymeric substances (EPS) modelling, and suggestions are put forward as to good modelling practice with regard to MBR modelling both for end-users and academia. A last section highlights shortcomings and future needs for improved biological modelling of MBR processes. (c) 2010 Elsevier Ltd. All rights reserved.

Evaluation of acute ecotoxicity removal from industrial wastewater using a battery of rapid bioassays.

PubMed

Dries, Jan; Daens, Dominique; Geuens, Luc; Blust, Ronny

2014-01-01

The present study compares conventional wastewater treatment technologies (coagulation-flocculation and activated sludge) and powdered activated carbon (PAC) treatment for the removal of acute ecotoxicity from wastewater generated by tank truck cleaning (TTC) processes. Ecotoxicity was assessed with a battery of four commercially available rapid biological toxicity testing systems, verified by the US Environmental Protection Agency. Chemical coagulation-flocculation of raw TTC wastewater had no impact on the inhibition of the bioluminescence by Vibrio fischeri (BioTox assay). Subsequent biological treatment with activated sludge without PAC resulted in BioTox inhibition-free effluent (<10% inhibition). In contrast, activated sludge treatment without PAC produced an effluent that significantly inhibited (>50%) (i) the bioluminescence by Photobacterium leiognathi (ToxScreen³ test kit), (ii) the photosynthesis by the green algae Chlorella vulgaris (LuminoTox SAPS test kit), and (iii) the particle ingestion by the crustacean Thamnocephalus platyurus (Rapidtoxkit test kit). The lowest inhibition was measured after activated sludge treatment with the highest PAC dose (400 mg/L), demonstrating the effectiveness of PAC treatment for ecotoxicity removal from TTC wastewater. In conclusion, the combination of bioassays applied in the present study represents a promising test battery for rapid ecotoxicty assessment in wastewater treatment.

Fe-As sludge stability and effluent quality for a two-stage As-contaminated water treatment with Fe(II) and aeration.

PubMed

Zhuang, J Ming; Hobenshield, Evan; Walsh, Tony

2009-02-01

A two-stage (I and II) lab-scale treatment system has been studied for arsenic removal from water using Fe(II) and lignosulphonates with aeration. In stage I, using an Fe/As mole ratio of 1.5-2.5 at a pH of around 6.5-7.5, the dissolved arsenic can be reduced with Fe(II) oxidation-precipitation from an initial 72 mg L(-1) to < 2 mg L(-1). The generated sludge is entirely recycled to the second tank of stage II. In the first tank of stage II, the water is further treated with the same amount of Fe(II) as that used in stage I, in the presence of lignosulphonates and aeration. The air-oxidization of Fe(II) to Fe(III) is continued for about 30 minutes at a pH of around 7.0-8.0. The water output from the first tank is transferred to the second tank in which mixing under aeration occurs with the sludge recycled from stage I. Accordingly, the dissolved arsenic in the effluent is reduced to < 0.1 mg L(-1). The results show that this two-stage process can save more than 50% of total chemical costs, and reduce the amount of sludge by more than 50%, in comparison with the conventional Fe(III)/lime-treatment process. According to US EPA regulations, the final Fe-As sludge is classified as non-hazardous materials by the Toxicity Characteristic Leaching Procedure. But, the study shows that the instability of Fe-As sludge could be influenced by some factors, such as higher pH levels, a longer water-leaching time and larger water-leaching volume, leading to the liberation of more dissolvable As species. After being treated with Ligmet stabilizer, the Fe-As sludge showed an improved stability under varying pH conditions and large amounts of water leaching. The treated Fe-As sludge is suitable for landfill disposal.

Effective water content reduction in sewage wastewater sludge using magnetic nanoparticles.

PubMed

Lakshmanan, Ramnath; Kuttuva Rajarao, Gunaratna

2014-02-01

The present work compares the use of three flocculants for sedimentation of sludge and sludge water content from sewage wastewater i.e. magnetic iron oxide nanoparticles (MION), ferrous sulfate (chemical) and Moringa crude extract (protein). Sludge water content, wet/dry weight, turbidity and color were performed for, time kinetics and large-scale experiment. A 30% reduction of the sludge water content was observed when the wastewater was treated with either protein or chemical coagulant. The separation of sludge from wastewater treated with MION was achieved in less than 5min using an external magnet, resulted in 95% reduction of sludge water content. Furthermore, MION formed denser flocs and more than 80% reduction of microbial content was observed in large volume experiments. The results revealed that MION is efficient in rapid separation of sludge with very low water content, and thus could be a suitable alternative for sludge sedimentation and dewatering in wastewater treatment processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

AEROBIC AND ANAEROBIC TREATMENT OF C.I. DISPERSE BLUE 79 - VOLUME I

EPA Science Inventory

This study was conducted to determine the fate of C.I. Disperse Blue 79, one of the largest production volume dyes, and select biodegradation products in a conventionally operated activated sludge process and an anaerobic sludge digestion system. To achieve this objective, a pilo...

AEROBIC AND ANAEROBIC TREATMENT OF C.I. DISPERSE BLUE 79 - VOLUME II, APPENDICES

EPA Science Inventory

This study was conducted to determine the fate of C.I. Disperse Blue 79, one of the largest production volume dyes, and select biodegradation products in a conventionally operated activated sludge process and an anaerobic sludge digestion system. To achieve this objective, a pilo...

40 CFR Appendix Xi to Part 266 - Lead-Bearing Materials That May be Processed in Exempt Lead Smelters

Code of Federal Regulations, 2012 CFR

2012-07-01

... analyses Acid filters Baghouse bags Clothing (e.g., coveralls, aprons, shoes, hats, gloves) Sweepings Air filter bags and cartridges Respiratory cartridge filters Shop abrasives Stacking boards Waste shipping... pallets Water treatment sludges, filter cakes, residues, and solids Emission control dusts, sludges...

40 CFR Appendix Xi to Part 266 - Lead-Bearing Materials That May be Processed in Exempt Lead Smelters

Code of Federal Regulations, 2013 CFR

2013-07-01

... analyses Acid filters Baghouse bags Clothing (e.g., coveralls, aprons, shoes, hats, gloves) Sweepings Air filter bags and cartridges Respiratory cartridge filters Shop abrasives Stacking boards Waste shipping... pallets Water treatment sludges, filter cakes, residues, and solids Emission control dusts, sludges...

40 CFR Appendix Xi to Part 266 - Lead-Bearing Materials That May be Processed in Exempt Lead Smelters

Code of Federal Regulations, 2014 CFR

2014-07-01

... analyses Acid filters Baghouse bags Clothing (e.g., coveralls, aprons, shoes, hats, gloves) Sweepings Air filter bags and cartridges Respiratory cartridge filters Shop abrasives Stacking boards Waste shipping... pallets Water treatment sludges, filter cakes, residues, and solids Emission control dusts, sludges...

40 CFR Appendix Xi to Part 266 - Lead-Bearing Materials That May be Processed in Exempt Lead Smelters

Code of Federal Regulations, 2011 CFR

2011-07-01

... analyses Acid filters Baghouse bags Clothing (e.g., coveralls, aprons, shoes, hats, gloves) Sweepings Air filter bags and cartridges Respiratory cartridge filters Shop abrasives Stacking boards Waste shipping... pallets Water treatment sludges, filter cakes, residues, and solids Emission control dusts, sludges...

40 CFR Appendix Xi to Part 266 - Lead-Bearing Materials That May be Processed in Exempt Lead Smelters

Code of Federal Regulations, 2010 CFR

2010-07-01

... analyses Acid filters Baghouse bags Clothing (e.g., coveralls, aprons, shoes, hats, gloves) Sweepings Air filter bags and cartridges Respiratory cartridge filters Shop abrasives Stacking boards Waste shipping... pallets Water treatment sludges, filter cakes, residues, and solids Emission control dusts, sludges...

Improvement of primary settling performance with activated sludge.

PubMed

Yetis, U; Tarlan, E

2002-04-01

In biological treatment plants employing activated sludge processes, it is possible to recirculate some portion of the waste activated sludge that is not sent to the aeration basin, to the inlet of the primary sedimentation tanks. But in the literature there is no detailed information about the conditions, ratios and the characteristics of the waste sludge that can be recirculated back. However, depending on its settling characteristics, the addition of waste activated sludge to raw wastewater may improve primary settling. Settling tests have shown that the effect of waste activated sludge on primary settling is strongly dependent on the mean cell residence time (or sludge age), theta(c), of the waste activated sludge and also on the suspended solids concentration. Different sludge ages of 4, 6, 8, 10, 14, 20 and 26 days, and for each sludge age at least five different initial suspended solids concentrations were studied. A sludge age of 8-10 days achieved the optimum efficiency in terms of the remaining suspended solids concentration as well as percent-suspended solids removal. Also, the settled sludge volumes were measured throughout the experiments; so, the comparison was made between settled sludge volumes, initial suspended solids (SS) concentrations and theta(c).

Potential of phosphorus recovery from sewage sludge and manure ash by thermochemical treatment.

PubMed

Havukainen, Jouni; Nguyen, Mai Thanh; Hermann, Ludwig; Horttanainen, Mika; Mikkilä, Mirja; Deviatkin, Ivan; Linnanen, Lassi

2016-03-01

All life forms require phosphorus (P), which has no substitute in food production. The risk of phosphorus loss from soil and limited P rock reserves has led to the development of recycling P from industrial residues. This study investigates the potential of phosphorus recovery from sewage sludge and manure ash by thermochemical treatment (ASH DEC) in Finland. An ASH DEC plant could receive 46-76 kt/a of sewage sludge ash to produce 51-85 kt/a of a P-rich product with a P2O5 content of 13-18%, while 320-750 kt/a of manure ash could be supplied to produce 350-830 kt/a of a P-rich product with a P content of 4-5%. The P2O5 potential in the total P-rich product from the ASH DEC process using sewage sludge and manure ash is estimated to be 25-47 kt/a, which is significantly more than the P fertilizer demand in Finland's agricultural industries. The energy efficiency of integrated incineration and the ASH DEC process is more dependent on the total solid content and the subsequent need for mechanical dewatering and thermal drying than on the energy required by the ASH DEC process. According to the results of this study, the treated sewage sludge and manure ash using the ASH DEC process represent significant potential phosphorus sources for P fertilizer production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental and economic life cycle assessment for sewage sludge treatment processes in Japan.

PubMed

Hong, Jinglan; Hong, Jingmin; Otaki, Masahiro; Jolliet, Olivier

2009-02-01

Life cycle assessment for sewage sludge treatment was carried out by estimating the environmental and economic impacts of the six alternative scenarios most often used in Japan: dewatering, composting, drying, incineration, incinerated ash melting and dewatered sludge melting, each with or without digestion. Three end-of-life treatments were also studied: landfilling, agricultural application and building material application. The results demonstrate that sewage sludge digestion can reduce the environmental load and cost through reduced dry matter volume. The global warming potential (GWP) generated from incineration and melting processes can be significantly reduced through the reuse of waste heat for electricity and/or heat generation. Equipment production in scenarios except dewatering has an important effect on GWP, whereas the contribution of construction is negligible. In addition, the results show that the dewatering scenario has the highest impact on land use and cost, the drying scenario has the highest impact on GWP and acidification, and the incinerated ash melting scenario has the highest impact on human toxicity due to re-emissions of heavy metals from incinerated ash in the melting unit process. On the contrary, the dewatering, composting and incineration scenarios generate the lowest impact on human toxicity, land use and acidification, respectively, and the incinerated ash melting scenario has the lowest impact on GWP and cost. Heavy metals released from atmospheric effluents generated the highest human toxicity impact, with the effect of dioxin emissions being significantly lower. This study proved that the dewatered sludge melting scenario is an environmentally optimal and economically affordable method.

Treatment of azo dye Acid Orange 52 using ozonation and completed-mixed activated sludge process

NASA Astrophysics Data System (ADS)

Abidin, C. Z. A.; Fahmi; Ong, S. A.; Ahmad, R.; Sabri, S. N.

2017-06-01

In this study, the characteristic of colour and COD removal of azo dye Acid Orange 52 (AO52) by ozonation, in combination with complete-mixed activated sludge process (CMAS) was evaluated. The experimentation was arranged in two phases: during the first one, only ozonation was performed, while, during the second phase, it was integrated with CMAS. The performance of colour and COD concentration of AO52 with and without CMAS treatment, is compared and evaluated. From the results, it is obvious that high decolourization from the start of CMAS was contributed from the pre-treatments. The colour removal was due to the fact that ozonation able to cleave the azo bonds that represent colour. Thus, CMAS without pre-treatment are unable to decolourize the dyes sufficiently. 59.6% COD was removed from the first-stage, while merely 9.8% COD fraction removed from the subsequence second-stage CMAS. It is suggested that the rapid COD removal without ozonation are due to activated sludge adsorption processes. The decreased of mixed liquor suspended solids (MLSS) affected the CMAS performances, as the biomass decreased due to lack of nutrient for activated sludge microorganisms to multiply. Results from pre-ozonation alone contributed more than 50% of total COD removal, which indicated that at higher ozone dosage, tend to mineralize azo dye. Thus, ozonation not oxidized the dye though complete mineralization that produce carbon dioxide and water. However, it is a potential process for enhancing colour removal and biodegradability of dye-containing wastewater, once the appropriate ozonation time is determined. Therefore, the role of ozonation seems to break down the dye molecules and created ozonation by-product that is easily biodegraded in the subsequent biological treatment.

Benchmark simulation Model no 2 in Matlab-simulink: towards plant-wide WWTP control strategy evaluation.

PubMed

Vreck, D; Gernaey, K V; Rosen, C; Jeppsson, U

2006-01-01

In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment processes. Extended evaluation criteria are proposed for plant-wide control strategy assessment. Default open-loop and closed-loop strategies are also proposed to be used as references with which to compare other control strategies. Simulations indicate that the BM2 is an appropriate tool for plant-wide control strategy evaluation.

Bioaugmented sulfur-oxidizing denitrification system with Alcaligenes defragrans B21 for high nitrate containing wastewater treatment.

PubMed

Flores, Angel; Nisola, Grace M; Cho, Eulsaeng; Gwon, Eun-Mi; Kim, Hern; Lee, Changhee; Park, Shinjung; Chung, Wook-Jin

2007-05-01

The performance of enriched sludge augmented with the B21 strain of Alcaligenes defragrans was compared with that of enriched sludge, as well as with pure Alcaligenes defragrans B21, in the context of a sulfur-oxidizing denitrification (SOD) process. In synthetic wastewater treatment containing 100-1,000 mg NO3-N/L, the single strain-seeded system exhibited superior performance, featuring higher efficiency and a shorter startup period, provided nitrate loading rate was less than 0.2 kg NO3-N/m(3) per day. At nitrate loading rate of more than 0.5 kg NO3-N/m(3) per day, the bioaugmented sludge system showed higher resistance to shock loading than two other systems. However, no advantage of the bioaugmented system over the enriched sludge system without B21 strain was observed in overall efficiency of denitrification. Both the bioaugmented sludge and enriched sludge systems obtained stable denitrification performance of more than 80% at nitrate loading rate of up to 2 kg NO3-N/m(3) per day.

In situ identification of nocardioform actinomycetes in activated sludge using fluorescent rRNA-targeted oligonucleotide probes.

PubMed

Schuppler, M; Wagner, M; Schön, G; Göbel, U B

1998-01-01

Hitherto, few environmental samples have been investigated by a 'full cycle rRNA analysis'. Here the results of in situ hybridization experiments with specific rRNA-targeted oligonucleotide probes developed on the basis of new sequences derived from a previously described comparative 16S rRNA analysis of nocardioform actinomycetes in activated sludge are reported. Application of the specific probes enabled identification and discrimination of the distinct populations of nocardioform actinomycetes in activated sludge. One of the specific probes (DLP) detected rod-shaped bacteria which were found in 13 of the 16 investigated sludge samples from various wastewater treatment plants, suggesting their importance in the wastewater treatment process. Another probe (GLP2) hybridized with typically branched filaments of nocardioforms mainly found in samples from enhanced biological phosphorus removal plants, suggesting that these bacteria are involved in sludge foaming. The combination of in situ hybridization with fluorescently labelled rRNA-targeted oligonucleotide probes and confocal laser scanning microscopy improved the detection of nocardioform actinomycetes, which often showed only weak signals inside the activated-sludge flocs.

Occurrence, identification and removal of microplastic particles and fibers in conventional activated sludge process and advanced MBR technology.

PubMed

Lares, Mirka; Ncibi, Mohamed Chaker; Sillanpää, Markus; Sillanpää, Mika

2018-04-15

Wastewater treatment plants (WWTPs) are acting as routes of microplastics (MPs) to the environment, hence the urgent need to examine MPs in wastewaters and different types of sludge through sampling campaigns covering extended periods of time. In this study, the efficiency of a municipal WWTP to remove MPs from wastewater was studied by collecting wastewater and sludge samples once in every two weeks during a 3-month sampling campaign. The WWTP was operated based on the conventional activated sludge (CAS) process and a pilot-scale membrane bioreactor (MBR). The microplastic particles and fibers from both water and sludge samples were identified by using an optical microscope, Fourier Transform Infrared (FTIR) microscope and Raman microscope. Overall, the retention capacity of microplastics in the studied WWTP was found to be 98.3%. Most of the MP fraction was removed before the activated sludge process. The efficiency of an advanced membrane bioreactor (MBR) technology was also examined. The main related finding is that MBR permeate contained 0.4 MP/L in comparison with the final effluent of the CAS process (1.0 MP/L). According to this study, both microplastic fibers and particles are discharged from the WWTP to the aquatic environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Environmental optimization of chromium recovery from tannery sludge using a life cycle assessment approach.

PubMed

Kiliç, Eylem; Puig, Rita; Baquero, Grau; Font, Joaquim; Colak, Selime; Gürler, Deniz

2011-08-15

Life cycle assessment (LCA) was used to evaluate the environmental impact of an oxidative chromium recovery method from tannery sludge, in comparison with the usual landfilling process. Three improvement options (water reduction, byproduct use and anaerobic sludge digestion) were considered. The results showed that the proposed chromium recovery process would be better environmentally than conventional landfilling in all the evaluated impact categories if the amount of chromium recovered was 43 kg per ton of sludge. This amount could be recovered if the chromium concentration was about 20 times higher than that considered in this study. Alternatively, a lower chromium concentration would produce a better result if the recovery method was optimized and implemented at industrial rather than laboratory scale, and if more accurate data were provided on environmental credits for avoiding the chromium production process. Thus, the recovery method is environmentally beneficial when tannery sludge contains a chromium concentration of about 100,000 ppm. According to the literature, such concentrations are not unusual. The results could serve as the basis for further environmental improvements in chromium recovery and tannery sludge management and should be used in decision-making processes, especially for end-of-pipe treatments. Copyright © 2011 Elsevier B.V. All rights reserved.

The treatment of chromium containing wastewater using electrocoagulation and the production of ceramic pigments from the resulting sludge.

PubMed

Tezcan Un, Umran; Onpeker, Suzan Eroglu; Ozel, Emel

2017-09-15

This research experimentally investigates the treatment of authentic electroplating wastewater with high Cr(VI) content by electrocoagulation with the obtained sludge being reused as a raw material to produce inorganic pigments. A zero waste process is introduced to help conserve resources and to minimize environmental effects. The effects of operational parameters on electrocoagulation are determined in a batch stirred reactor using an iron electrode. The best performance was observed when a current density 20 mA/cm 2 , pH 2.4 and 0.05 M NaCl electrolyte were maintained. The initial Cr(VI) concentration of 1000 mg/L was almost completely abated (∼100%) at an energy cost of 2.68 kWh/m 3 , fulfilling the EPA guideline of 2.77 mg/L within a single step process. The sludge was characterized using XRD and XRF showing that the sludge is a rich source of iron and chromium and can be reused to produce value added ceramic pigments. Pigments prepared in this way appeared to be reddish brown and black color in transparent glaze and were also characterized using XRD and XRF. In this study, a zero waste process is successfully introduced with ∼100% Cr(VI) removal, with subsequent reuse of the resulting sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of Sulfur Dioxide from Flue Gas Using the Sludge Sodium Humate

PubMed Central

Hu, Guoxin

2013-01-01

This study shows the ability of sodium humate from alkaline treatment sludge on removing sulfur dioxide (SO2) in the simulated flue gas. Experiments were conducted to examine the effect of various operating parameters, like the inlet SO2 concentration or temperature or O2, on the SO2 absorption efficiency and desulfurization time in a lab-scale bubbling reactor. The sludge sodium humate in the supernatant after alkaline sludge treatment shows great performance in SO2 absorption, and such efficiency can be maintained above 98% with 100 mL of this absorption solution at 298 K (flue gas rate of 0.12 m3/h). The highest SO2 absorption by 1.63 g SHA-Na is 0.946 mmol in the process, which is translated to 0.037 g SO2 g−1 SHA-Na. The experimental results indicate that the inlet SO2 concentration slightly influences the SO2 absorption efficiency and significantly influences the desulfurization time. The pH of the absorption solution should be above 3.5 in this process in order to make an effective desulfurization. The products of this process were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. It can be seen that the desulfurization products mainly contain sludge humic acid sediment, which can be used as fertilizer components. PMID:24453875

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms

PubMed Central

Mantilla-Calderon, David

2017-01-01

ABSTRACT The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. PMID:28411227

Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

PubMed

Mantilla-Calderon, David; Hong, Pei-Ying

2017-07-01

The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic resistance gene was detected in the aerobic sludge by a cultivation method. A subpopulation of persister E. coli cells was also detected in the aerobic sludge. The findings of this study suggest potential areas of concern arising from pathogenic and antibiotic-resistant E. coli during both anaerobic and aerobic sludge treatment processes. Copyright © 2017 Mantilla-Calderon and Hong.

Gaseous emissions from sewage sludge combustion in a moving bed combustor.

PubMed

Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

2015-12-01

Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions, such as the installation of exhaust gas-cleaning systems. According to previous studies, the efficient operation of such cleaning systems is also effective for metals emission control, which makes the combustion of sewage sludge a feasible treatment method from both energetic and environmental perspectives. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oxygen transfer and uptake, nutrient removal, and energy footprint of parallel full-scale IFAS and activated sludge processes.

PubMed

Rosso, Diego; Lothman, Sarah E; Jeung, Matthew K; Pitt, Paul; Gellner, W James; Stone, Alan L; Howard, Don

2011-11-15

Integrated fixed-film activated sludge (IFAS) processes are becoming more popular for both secondary and sidestream treatment in wastewater facilities. These processes are a combination of biofilm reactors and activated sludge processes, achieved by introducing and retaining biofilm carrier media in activated sludge reactors. A full-scale train of three IFAS reactors equipped with AnoxKaldnes media and coarse-bubble aeration was tested using off-gas analysis. This was operated independently in parallel to an existing full-scale activated sludge process. Both processes achieved the same percent removal of COD and ammonia, despite the double oxygen demand on the IFAS reactors. In order to prevent kinetic limitations associated with DO diffusional gradients through the IFAS biofilm, this systems was operated at an elevated dissolved oxygen concentration, in line with the manufacturer's recommendation. Also, to avoid media coalescence on the reactor surface and promote biofilm contact with the substrate, high mixing requirements are specified. Therefore, the air flux in the IFAS reactors was much higher than that of the parallel activated sludge reactors. However, the standardized oxygen transfer efficiency in process water was almost same for both processes. In theory, when the oxygen transfer efficiency is the same, the air used per unit load removed should be the same. However, due to the high DO and mixing requirements, the IFAS reactors were characterized by elevated air flux and air use per unit load treated. This directly reflected in the relative energy footprint for aeration, which in this case was much higher for the IFAS system than activated sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge.

PubMed

Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

2017-11-30

High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process "thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)". Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H₂ and CO₂ to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance.

Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

PubMed

Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

2016-01-01

A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kg COD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process.

Dielectric and electric properties as a tool to investigate the coagulation mechanism during sludge treatment.

PubMed

Mortadi, A; Chahid, El G; Nasrellah, H; Cherkaoui, O; El Moznine, R

2017-09-28

The analysis of the complex permittivity, electrical complex modulus and the hopping conductivity have been employed in order to investigate the impacts of calcium oxide during sludge treatment in textile such as coagulation process. In this context, impedance measurement was performed on five samples, including raw sludge and four compositions containing different amounts of calcium oxide: 2%, 3%, 4% and 5% (w/w). The dielectric spectra of each composition were described by the summation of a power law and a Cole-Cole relaxation model. The relaxation time and the magnitude of the dielectric relaxation obtained from the analysis of dielectric properties showed an increase up to 3% of these parameters with the addition of calcium oxide. Above this critical value, both parameters showed a very small change, suggesting that the aggregation became more stable. In addition, the evolution of the hopping conductivity reached a minimum value at this critical amount (3%). This evolution was well described by a double power law, which allowed us to estimate the optimal amount of the calcium oxide to achieve coagulation process. The analysis of the dielectric properties was found useful in monitoring aggregation processes that occur during the coagulation mechanism in textile sludge.

Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge

PubMed Central

Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

2017-01-01

High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process “thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)”. Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H2 and CO2 to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance. PMID:29189754

Treatment options for low-level radiologically contaminated ORNL filtercake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hom-Ti; Bostick, W.D.

1996-04-01

Water softening sludge (>4000 stored low level contaminated drums; 600 drums per year) generated by the ORNL Process Waste Treatment Plant must be treated, stabilized, and placed in safe storage/disposal. The sludge is primarily CaCO{sub 3} and is contaminated by low levels of {sup 90}Sr and {sup 137}Cs. In this study, microwave sintering and calcination were evaluated for treating the sludge. The microwave melting experiments showed promise: volume reductions were significant (3-5X), and the waste form was durable with glass additives (LiOH, fly ash). A commercial vendor using surrogate has demonstrated a melt mineralization process that yields a dense monolithicmore » waste form with a volume reduction factor (VR) of 7.7. Calcination of the sludge at 850-900 C yielded a VR of 2.5. Compaction at 4500 psi increased the VR to 4.2, but the compressed form is not dimensionally stable. Addition of paraffin helped consolidate fines and yielded a VR of 3.5. In conclusion, microwave melting or another form of vitrification is likely to be the best method; however for immediate implementation, the calculation/compaction/waxing process is viable.« less

Characterization of changes in floc morphology, extracellular polymeric substances and heavy metals speciation of anaerobically digested biosolid under treatment with a novel chelated-Fe2+ catalyzed Fenton process.

PubMed

He, Juanjuan; Yang, Peng; Zhang, Weijun; Cao, Bingdi; Xia, Hua; Luo, Xi; Wang, Dongsheng

2017-11-01

A novel chelated-Fe 2+ catalyzed Fenton process (CCFP) was developed to enhance dewatering performance of anaerobically digested biosolid, and changes in floc morphology, extracellular polymeric substances (EPS) and heavy metals speciation were also investigated. The results showed that addition of chelating agents caused EPS solubilization by binding multivalent cations. Like traditional Fenton, CCFP performed well in improving anaerobically digested sludge dewatering property. The highly active radicals (OH, O 2 - ) produced in classical Fenton and CCFP were responsible for sludge flocs destruction and consequently degradation of biopolymers into small molecules. Furthermore, more plentiful pores and channels were presented in cake after Fenton treatment, which was conducive to water drainage under mechanical compression. Additionally, a portion of active heavy metals in the form of oxidizable and reducible states were dissolved under CCFP. Therefore, CCFP could greatly simplify the operating procedure of Fenton conditioning and improve its process adaptability for harmless treatment of biological sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance.

PubMed

Jin, Lingyun; Zhang, Guangming; Zheng, Xiang

2015-02-01

A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K2FeO4 oxidation and KMnO4 oxidation. The degree of disintegration (DDCOD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K2FeO4 oxidation was more efficient than KMnO4 oxidation. The content of free water increased obviously with K2FeO4 and KMnO4 oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K2FeO4 oxidation, and increased slightly with KMnO4 oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K2FeO4 oxidation, and did not changed with KMnO4 oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K2FeO4 and KMnO4 oxidation improved the sludge dewaterability. Copyright © 2014. Published by Elsevier B.V.

Occurrence and activity of Archaea in aerated activated sludge wastewater treatment plants.

PubMed

Gray, Neil D; Miskin, Ian P; Kornilova, Oksana; Curtis, Thomas P; Head, Ian M

2002-03-01

The occurrence, distribution and activity of archaeal populations within two aerated, activated sludge wastewater treatment systems, one treating domestic waste and the second treating mixed domestic and industrial wastewater, were investigated by denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified ribosomal RNA gene fragments and process measurements. In the plant receiving mixed industrial and domestic waste the archaeal populations found in the mixed liquor were very similar to those in the influent sewage, though a small number of DGGE bands specific to the mixed liquor were identified. In contrast, the activated sludge treating principally domestic waste harboured distinct archaeal populations associated with the mixed liquor that were not prevalent in the influent sewage. We deduce that the Archaea in the plant treating mixed wastewater were derived principally from the influent, whereas those in the plant treating solely domestic waste were actively growing in the treatment plant. Archaeal 16S rRNA gene sequences related to the Methanosarcinales, Methanomicrobiales and the Methanobacteriales were detected. Methanogenesis was measured in activated sludge samples incubated under oxic and anoxic conditions, demonstrating that the methanogens present in both activated sludge plants were active only in anoxic incubations. The relatively low rates of methanogenesis measured indicated that, although active, the methanogens play a minor role in carbon turnover in activated sludge.

Anaerobic digestion potential of urban organic waste: a case study in Malmö.

PubMed

Davidsson, Asa; Jansen, Jes la Cour; Appelqvist, Björn; Gruvberger, Christopher; Hallmer, Martin

2007-04-01

A study of existing organic waste types in Malmö, Sweden was performed. The purpose was to gather information about organic waste types in the city to be able to estimate the potential for anaerobic treatment in existing digesters at the wastewater treatment plan (WWTP). The urban organic waste types that could have a significant potential for anaerobic digestion amount to about 50 000 tonnes year(-1) (sludge excluded). Some of the waste types were further evaluated by methane potential tests and continuous pilot-scale digestion. Single-substrate digestion and co-digestion of pre-treated, source-sorted organic fraction of municipal solid waste, wastewater sludge, sludge from grease traps and fruit and vegetable waste were carried out. The experiments showed that codigestion of grease sludge and WWTP sludge was a better way of making use of the methane potential in the grease trap sludge than single-substrate digestion. Another way of increasing the methane production in sludge digesters is to add source-sorted organic fraction of municipal solid waste (SSOFMSW). Adding SSOFMSW (20% of the total volatile solids) gave a 10-15% higher yield than could be expected by comparison with separate digestion of sludge respective SSOFMSW. Co-digestion of sludge and organic waste is beneficial not just for increasing gas production but also for stabilizing the digestion process. This was seen when co-digesting fruit and vegetable waste and sludge. When co-digested with sludge, this waste gave a better result than the separate digestion of fruit and vegetable waste. Considering single-substrate digestion, SSOFMSW is the only waste in the study which makes up a sufficient quantity to be suitable as the base substrate in a full-scale digester that is separated from the sludge digestion. The two types of SSOFMSW tested in the pilot-scale digestion were operated successfully at mesophilic temperature. By adding SSOFMSW, grease trap sludge and fruit and vegetables waste to sludge digesters at the wastewater treatment plant, the yearly energy production from methane could be expected to increase from 24 to 43 GWh.

Effects of biochar on nitrogen transformation and heavy metals in sludge composting.

PubMed

Liu, Wei; Huo, Rong; Xu, Junxiang; Liang, Shuxuan; Li, Jijin; Zhao, Tongke; Wang, Shutao

2017-07-01

Composting is regarded as an effective treatment to suppress pathogenic organisms and stabilize the organic material in sewage sludge. This study investigated the use of biochar as an amendment to improve the composting effectiveness and reduce the bioavailability of heavy metals and loss of nitrogen during composting. Biochar of 0%, 1%, 3%, 5% and 7% were added into a mixture of sludge and straw, respectively. The use of biochar, even in small amounts, altered the composting process and the properties of the end products. Biochar addition resulted in a higher pile temperature (66°C) and could reduce nitrogen loss by transforming ammonium into nitrite. In the 5% biochar group, the final product from sludge composting, ammonia nitrogen, decreased by 22.4% compared to the control, and nitrate nitrogen increased by 310.6%. Considering temperature and N transformation, the treatment with 5% biochar is suggested for sludge composting. Copyright © 2017 Elsevier Ltd. All rights reserved.

Valorization of pellets from municipal WWTP sludge in lightweight clay ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cusido, Joan A., E-mail: joan.antoni.cusido@upc.edu; Soriano, Cecilia

2011-06-15

A direct result of the growing number of municipal wastewater-treatment plants (WWTPs) has been an increase in the generation of large amounts of sewage sludge that requires environmentally acceptable final destination. To decrease the volume of sludge, a common technique is drying the sludge at a low temperature in rotary kilns. The result of this process is a granulated material consisting of dehydrated sludge pellets. After this treatment, this pelletized material becomes easier to manipulate, but it also becomes a more toxic waste, containing dangerous substances, mostly of the lipid type. At its final stage, this material is usually incinerated,more » used as a comburent material, used as an agricultural fertilizer, or used in the cement industry. Each application has its own problems and requires remediation measures from the safety and environmental viewpoints. In this study, we looked beyond these possible applications and analyzed the transformation of sewage sludge through a ceramization process into a material similar to expanded clays; we subsequently explored its uses in the building industry or in the agriculture industry, among others. Both the properties of the product material and the production method were characterized, and an environmental analysis was conducted. The new, lightweight material had a microstructure with open porosity and low thermal conductivity. Environmental characterization such as the leaching test revealed that undetectable amounts of hazardous metals from the sludge were present in the leachate after the sludge went through a thermal treatment, despite their initial presence (with the exception of vanadium, which could pose some restrictions on some of the proposed uses for the final product). Toxicity tests also showed negative results. The study of gaseous emissions during production revealed emissions factors similar to those during the production of conventional clay ceramics, although with higher organic emissions. As for conventional clay ceramics, industrial production would require the implementation of some type of air-depuration system. The results showed that the ceramization of sludge pellets is a promising valorization technique worth considering from both the economic and technological perspectives.« less

Valorization of pellets from municipal WWTP sludge in lightweight clay ceramics.

PubMed

Cusidó, Joan A; Soriano, Cecilia

2011-06-01

A direct result of the growing number of municipal wastewater-treatment plants (WWTPs) has been an increase in the generation of large amounts of sewage sludge that requires environmentally acceptable final destination. To decrease the volume of sludge, a common technique is drying the sludge at a low temperature in rotary kilns. The result of this process is a granulated material consisting of dehydrated sludge pellets. After this treatment, this pelletized material becomes easier to manipulate, but it also becomes a more toxic waste, containing dangerous substances, mostly of the lipid type. At its final stage, this material is usually incinerated, used as a comburent material, used as an agricultural fertilizer, or used in the cement industry. Each application has its own problems and requires remediation measures from the safety and environmental viewpoints. In this study, we looked beyond these possible applications and analyzed the transformation of sewage sludge through a ceramization process into a material similar to expanded clays; we subsequently explored its uses in the building industry or in the agriculture industry, among others. Both the properties of the product material and the production method were characterized, and an environmental analysis was conducted. The new, lightweight material had a microstructure with open porosity and low thermal conductivity. Environmental characterization such as the leaching test revealed that undetectable amounts of hazardous metals from the sludge were present in the leachate after the sludge went through a thermal treatment, despite their initial presence (with the exception of vanadium, which could pose some restrictions on some of the proposed uses for the final product). Toxicity tests also showed negative results. The study of gaseous emissions during production revealed emissions factors similar to those during the production of conventional clay ceramics, although with higher organic emissions. As for conventional clay ceramics, industrial production would require the implementation of some type of air-depuration system. The results showed that the ceramization of sludge pellets is a promising valorization technique worth considering from both the economic and technological perspectives. Copyright © 2011 Elsevier Ltd. All rights reserved.

Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous catalytic ozonation and biological process.

PubMed

Zhuang, Haifeng; Han, Hongjun; Jia, Shengyong; Hou, Baolin; Zhao, Qian

2014-08-01

Advanced treatment of biologically pretreated coal gasification wastewater (CGW) was investigated employing heterogeneous catalytic ozonation integrated with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process. The results indicated that catalytic ozonation with the prepared catalyst (i.e. MnOx/SBAC, sewage sludge was converted into sludge based activated carbon (SBAC) which loaded manganese oxides) significantly enhanced performance of pollutants removal by generated hydroxyl radicals. The effluent of catalytic ozonation process was more biodegradable and less toxic than that in ozonation alone. Meanwhile, ANMBBR-BAF showed efficient capacity of pollutants removal in treatment of the effluent of catalytic ozonation at a shorter reaction time, allowing the discharge limits to be met. Therefore, the integrated process with efficient, economical and sustainable advantages was suitable for advanced treatment of real biologically pretreated CGW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Changes in the process performance, sludge production and microbial activity in an activated sludge reactor with addition of a metabolic uncoupler under different operating conditions.

PubMed

Ferrer-Polonio, E; Fernández-Navarro, J; Alonso-Molina, J L; Amorós-Muñoz, I; Bes-Piá, A; Mendoza-Roca, J A

2017-12-01

Sludge production in wastewater treatment plants is nowadays a big concern due to the high produced amounts and their characteristics. Consequently, the study of techniques that reduce the sludge generation in wastewater treatment plants is becoming of great importance. In this work, four laboratory sequencing batch reactors (SBRs), which treated municipal wastewater, were operated to study the effect of adding the metabolic uncoupler 3,3',4',5-tetrachlorosalicylanilide (TCS) on the sludge reduction, the SBRs performance and the microbial hydrolytic enzymatic activities (MHEA). In addition, different operating conditions of the SBRs were tested to study the effect of the TCS on the process: two dissolved oxygen (DO) concentrations (2 and 9 mg L -1 ) and two F/M ratio (0.18 and 0.35 g COD·g MLVSS -1 ·d -1 ). The sludge production decreased under high DO concentrations. At the same time, the DNA and EPS production increased in the four SBRs. After these stress conditions, the performance of the reactors were recovered when DO was around 2 mg L -1 . From that moment on, results showed that TCS addition implied a reduction of the adenosine triphosphate (ATP) production, which implied a decrease in the sludge production. In spite of this reduction, the SBRs performances did not decay due to the increase in the global MHEA. Additionally, the sludge reduction was enhanced by the increase of the F/M ratio, achieving 28% and 60% of reduction for the low and the high F/M ratio, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ion Trapping of Amines in Protozoa: A Novel Removal Mechanism for Micropollutants in Activated Sludge.

PubMed

Gulde, Rebekka; Anliker, Sabine; Kohler, Hans-Peter E; Fenner, Kathrin

2018-01-02

To optimize removal of organic micropollutants from the water cycle, understanding the processes during activated sludge treatment is essential. In this study, we hypothesize that aliphatic amines, which are highly abundant among organic micropollutants, are partly removed from the water phase in activated sludge through ion trapping in protozoa. In ion trapping, which has been extensively investigated in medical research, the neutral species of amine-containing compounds diffuse through the cell membrane and further into acidic vesicles present in eukaryotic cells such as protozoa. There they become trapped because diffusion of the positively charged species formed in the acidic vesicles is strongly hindered. We tested our hypothesis with two experiments. First, we studied the distribution of the fluorescent amine acridine orange in activated sludge by confocal fluorescence imaging. We observed intense fluorescence in distinct compartments of the protozoa, but not in the bacterial biomass. Second, we investigated the distribution of 12 amine-containing and eight control micropollutants in both regular activated sludge and sludge where the protozoa had been inactivated. In contrast to most control compounds, the amine-containing micropollutants displayed a distinctly different behavior in the noninhibited sludge compared to the inhibited one: (i) more removal from the liquid phase; (ii) deviation from first-order kinetics for the removal from the liquid phase; and (iii) higher amounts in the solid phase. These results provide strong evidence that ion trapping in protozoa occurs and that it is an important removal mechanism for amine-containing micropollutants in batch experiments with activated sludge that has so far gone unnoticed. We expect that our findings will trigger further investigations on the importance of this process in full-scale wastewater treatment systems, including its relevance for accumulation of ammonium.

Small hazardous waste generators in developing countries: use of stabilization/solidification process as an economic tool for metal wastewater treatment and appropriate sludge disposal.

PubMed

Silva, Marcos A R; Mater, Luciana; Souza-Sierra, Maria M; Corrêa, Albertina X R; Sperb, Rafael; Radetski, Claudemir M

2007-08-25

The aim of this study was to propose a profitable destination for an industrial sludge that can cover the wastewater treatment costs of small waste generators. Optimized stabilization/solidification technology was used to treat hazardous waste from an electroplating industry that is currently released untreated to the environment. The stabilized/solidified (S/S) waste product was used as a raw material to build concrete blocks, to be sold as pavement blocks or used in roadbeds and/or parking lots. The quality of the blocks containing a mixture of cement, lime, clay and waste was evaluated by means of leaching and solubility tests according to the current Brazilian waste regulations. Results showed very low metal leachability and solubility of the block constituents, indicating a low environmental impact. Concerning economic benefits from the S/S process and reuse of the resultant product, the cost of untreated heavy metal-containing sludge disposal to landfill is usually on the order of US$ 150-200 per tonne of waste, while 1tonne of concrete roadbed blocks (with 25% of S/S waste constitution) has a value of around US$ 100. The results of this work showed that the cement, clay and lime-based process of stabilization/solidification of hazardous waste sludge is sufficiently effective and economically viable to stimulate the treatment of wastewater from small industrial waste generators.

Degradation of slime extracellular polymeric substances and inhibited sludge flocs destruction contribute to sludge dewaterability enhancement during fungal treatment of sludge using filamentous fungus Mucor sp. GY-1.

PubMed

Wang, Zhenyu; Zheng, Guanyu; Zhou, Lixiang

2015-09-01

Mechanisms responsible for the sludge dewaterability enhanced by filamentous fungi during fungal treatment of sludge were investigated in the present study. The filamentous fungus Mucor sp. GY-1, isolated from waste activated sludge, enhanced sludge dewaterability by 82.1% to achieve the lowest value of normalized sludge specific resistance to filtration (SRF), 8.18 × 10(10) m · L/kg · g-TSS. During the fungal treatment of sludge, 57.8% of slime extracellular polymeric substances (EPS) and 51.1% of polysaccharide in slime EPS were degraded, respectively, by Mucor sp. GY-1, contributing to the improvement of sludge dewaterability. Slime EPS is much more available for Mucor sp. GY-1 than either LB-EPS or TB-EPS that bound with microbial cells. In addition, filamentous fungus Mucor sp. GY-1 entrapped small sludge particles and inhibited the destruction of sludge flocs larger than 100 μm, thus enhancing sludge dewaterability, during fungal treatment of sludge using Mucor sp. GY-1. Copyright © 2015 Elsevier Ltd. All rights reserved.

MIUS wastewater technology evaluation

NASA Technical Reports Server (NTRS)

Poradek, J. C.

1976-01-01

A modular integrated utility system wastewater-treatment process is described. Research in the field of wastewater treatment is reviewed, treatment processes are specified and evaluated, and recommendations for system use are made. The treatment processes evaluated are in the broad categories of preparatory, primary, secondary, and tertiary treatment, physical-chemical processing, dissolved-solids removal, disinfection, sludge processing, and separate systems. Capital, operating, and maintenance costs are estimated, and extensive references are given.

Towards a comprehensive greenhouse gas emissions inventory for biosolids.

PubMed

Alvarez-Gaitan, J P; Short, Michael D; Lundie, Sven; Stuetz, Richard

2016-06-01

Effective handling and treatment of the solids fraction from advanced wastewater treatment operations carries a substantial burden for water utilities relative to the total economic and environmental impacts from modern day wastewater treatment. While good process-level data for a range of wastewater treatment operations are becoming more readily available, there remains a dearth of high quality operational data for solids line processes in particular. This study seeks to address this data gap by presenting a suite of high quality, process-level life cycle inventory data covering a range of solids line wastewater treatment processes, extending from primary treatment through to biosolids reuse in agriculture. Within the study, the impacts of secondary treatment technology and key parameters such as sludge retention time, activated sludge age and primary-to-waste activated sludge ratio (PS:WAS) on the life cycle inventory data of solids processing trains for five model wastewater treatment plant configurations are presented. BioWin(®) models are calibrated with real operational plant data and estimated electricity consumption values were reconciled against overall plant energy consumption. The concept of "representative crop" is also introduced in order to reduce the uncertainty associated with nitrous oxide emissions and soil carbon sequestration offsets under biosolids land application scenarios. Results indicate that both the treatment plant biogas electricity offset and the soil carbon sequestration offset from land-applied biosolids, represent the main greenhouse gas mitigation opportunities. In contrast, fertiliser offsets are of relatively minor importance in terms of the overall life cycle emissions impacts. Results also show that fugitive methane emissions at the plant, as well as nitrous oxide emissions both at the plant and following agricultural application of biosolids, are significant contributors to the overall greenhouse gas balance and combined are higher than emissions associated with transportation. Sensitivity analyses for key parameters including digester PS:WAS and sludge retention time, and assumed biosolids nitrogen content and agricultural availability also provide additional robustness and comprehensiveness to our inventory data and will facilitate more customised user analyses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Integration of aerobic granular sludge and mesh filter membrane bioreactor for cost-effective wastewater treatment.

PubMed

Li, Wen-Wei; Wang, Yun-Kun; Sheng, Guo-Ping; Gui, Yong-Xin; Yu, Lei; Xie, Tong-Qing; Yu, Han-Qing

2012-10-01

Conventional MBR has been mostly based on floc sludge and the use of costly microfiltration membranes. Here, a novel aerobic granule (AG)-mesh filter MBR (MMBR) process was developed for cost-effective wastewater treatment. During 32-day continuous operation, a predominance of granules was maintained in the system, and good filtration performance was achieved at a low trans-membrane pressure (TMP) of below 0.025 m. The granules showed a lower fouling propensity than sludge flocs, attributed to the formation of more porous biocake layer at mesh surface. A low-flux and low-TMP filtration favored a stable system operation. In addition, the reactor had high pollutant removal efficiencies, with a 91.4% chemical oxygen demand removal, 95.7% NH(4)(+) removal, and a low effluent turbidity of 4.1 NTU at the stable stage. This AG-MMBR process offers a promising technology for low-cost and efficient treatment of wastewaters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Air Emission Reduction Benefits of Biogas Electricity Generation at Municipal Wastewater Treatment Plants.

PubMed

Gingerich, Daniel B; Mauter, Meagan S

2018-02-06

Conventional processes for municipal wastewater treatment facilities are energy and materially intensive. This work quantifies the air emission implications of energy consumption, chemical use, and direct pollutant release at municipal wastewater treatment facilities across the U.S. and assesses the potential to avoid these damages by generating electricity and heat from the combustion of biogas produced during anaerobic sludge digestion. We find that embedded and on-site air emissions from municipal wastewater treatment imposed human health, environmental, and climate (HEC) damages on the order of $1.63 billion USD in 2012, with 85% of these damages attributed to the estimated consumption of 19 500 GWh of electricity by treatment processes annually, or 0.53% of the US electricity demand. An additional 11.8 million tons of biogenic CO 2 are directly emitted by wastewater treatment and sludge digestion processes currently installed at plants. Retrofitting existing wastewater treatment facilities with anaerobic sludge digestion for biogas production and biogas-fueled heat and electricity generation has the potential to reduce HEC damages by up to 24.9% relative to baseline emissions. Retrofitting only large plants (>5 MGD), where biogas generation is more likely to be economically viable, would generate HEC benefits of $254 annually. These findings reinforce the importance of accounting for use-phase embedded air emissions and spatially resolved marginal damage estimates when designing sustainable infrastructure systems.

Moringa oleifera-mediated coagulation of textile wastewater and its biodegradation using novel consortium-BBA grown on agricultural waste substratum.

PubMed

Bedekar, Priyanka A; Bhalkar, Bhumika N; Patil, Swapnil M; Govindwar, Sanjay P

2016-10-01

Generation of secondary sludge is a major concern of textile dye removal by coagulation process. Combinatorial coagulation-biodegradation treatment system has been found efficient in degradation of coagulated textile dye sludge. Moringa oleifera seed powder (700 mg L -1 ) was able to coagulate textile dyestuff from real textile wastewater with 98 % color removal. Novel consortium-BBA was found to decolorize coagulated dye sludge. Parameters that significantly affect coagulation process were optimized using response surface methodology. The bench-scale stirred tank reactor (50-L capacity) designed with optimized parameters for coagulation process could efficiently remove 98, 89, 78, and 67 % of American Dye Manufacturer's Institute (ADMI) in four repetitive cycles, respectively. Solid-state fermentation composting reactor designed to treat coagulated dye sludge showed 96 % removal of dye within 10 days. Coagulation of dyes from textile wastewater and degradation of coagulated dye sludge were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. Cell morphology assay, comet assay, and phytotoxicity confirmed the formation of less toxic products after coagulation and degradation mechanism.

SLUDGE RETRIEVAL FROM HANFORD K WEST BASIN SETTLER TANKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

ERPENBECK EG; LESHIKAR GA

In 2010, an innovative, remotely operated retrieval system was deployed to successfully retrieve over 99.7% of the radioactive sludge from ten submerged tanks in Hanford's K-West Basin. As part of K-West Basin cleanup, the accumulated sludge needed to be removed from the 0.5 meter diameter by 5 meter long settler tanks and transferred approximately 45 meters to an underwater container for sampling and waste treatment. The abrasive, dense, non-homogeneous sludge was the product of the washing process of corroded nuclear fuel. It consists of small (less than 600 micron) particles of uranium metal, uranium oxide, and various other constituents, potentiallymore » agglomerated or cohesive after 10 years of storage. The Settler Tank Retrieval System (STRS) was developed to access, mobilize and pump out the sludge from each tank using a standardized process of retrieval head insertion, periodic high pressure water spray, retraction, and continuous pumping of the sludge. Blind operations were guided by monitoring flow rate, radiation levels in the sludge stream, and solids concentration. The technology developed and employed in the STRS can potentially be adapted to similar problematic waste tanks or pipes that must be remotely accessed to achieve mobilization and retrieval of the sludge within.« less

Enhanced Cr bioleaching efficiency from tannery sludge with coinoculation of Acidithiobacillus thiooxidans TS6 and Brettanomyces B65 in an air-lift reactor.

PubMed

Fang, Di; Zhou, Li-Xiang

2007-09-01

Bioleaching process has been demonstrated to be an effective technology in removing Cr from tannery sludge, but a large quantity of dissolved organic matter (DOM) present in tannery sludge often exhibits a marked toxicity to chemolithoautotrophic bioleaching bacteria such as Acidithiobacillus thiooxidans. The purpose of the present study was therefore to enhance Cr bioleaching efficiencies through introducing sludge DOM-degrading heterotrophic microorganism into the sulfur-based sludge bioleaching system. An acid-tolerant DOM-degrading yeast strain Brettanomyces B65 was successfully isolated from a local Haining tannery sludge and it could metabolize sludge DOM as a source of energy and carbon for growth. A combined bioleaching experiment (coupling Brettanomyces B65 and A. thiooxidans TS6) performed in an air-lift reactor indicated that the rates of sludge pH reduction and ORP increase were greatly improved, resulting in enhanced Cr solubilization. Compared with the 5 days required for maximum solubilization of Cr for the control (single bioleaching process without inoculation of Brettanomyces B65), the bioleaching period was significantly shorten to 3 days for the combined bioleaching system. Moreover, little nitrogen and phosphorous were lost and the content of Cr was below the permitted levels for land application after 3 days of bioleaching treatment.

Silvicultural Use of Wastewater Sludge

Treesearch

J.B. Hart; P.V. Nguyen; D.H. Urie; Dale G. Brockway

1988-01-01

Generation of wastewater sludge in the United States has become a problem of increasing proportion, with annual production at 4 million tons in 1970 (Walsh 1976) and 7 million tons currently(Maness 1987). While population and industrial growth have contributed to this problem, legislation requiring higher standards of treatment for wastewater processed in the 15,378...

Vacuum Filtration. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Filer, Herb; Windram, Kendall

Three types of vacuum filters and their operation are described in this lesson. Typical filter cycle, filter components and their functions, process control parameters, expected performance, and safety/historical aspects are considered. Conditioning methods are also described, although it is suggested that lessons on sludge characteristics, sludge…

THE US POSITION AND FATE OF PATHOGENS IN SEWAGE SLUDGE AND THE US 40CFR503 REGULATION

EPA Science Inventory

This paper reviews the pathogenic microorganisms that may be found in sewage sludge and the commonly employed Class A and B treatment processes for controlling pathogens. It notes how extensively they are used and discusses issues and concerns with them. Preliminary findings of a...

Drying or anaerobic digestion of fish sludge: Nitrogen fertilisation effects and logistics.

PubMed

Brod, Eva; Oppen, Johan; Kristoffersen, Annbjørg Øverli; Haraldsen, Trond Knapp; Krogstad, Tore

2017-12-01

Application of fish sludge as fertiliser to agricultural land can contribute to closing nutrient cycles in fish farming. The effect of different treatment technologies on the nitrogen fertilisation effects of fish sludge was studied by a bioassay with barley (Hordeum vulgare), an incubation and a field experiment. Dried fish sludge resulted in relative agronomic efficiency of 50-80% compared with mineral fertiliser. The anaerobic digestate based on fish sludge (20 vol%) and dairy manure did not increase nitrogen uptake in barley. Increasing the ratio of fish sludge in the digestate increased the fertilisation effect, but requires optimisation of the biogas process. A simple logistics analysis conducted for a case hatchery showed that on-site drying and co-digestion of fish sludge in a central biogas plant can be regarded as equal in terms of costs. Norway can become an exporter of fish sludge-based recycling fertilisers if current regulations are modified to facilitate nutrient recycling.

Two-phase anaerobic digestion of partially acidified sewage sludge: a pilot plant study for safe sludge disposal in developing countries.

PubMed

Passio, Luca; Rizzoa, Luigi; Fuchs, Stephan

2012-09-01

The unsafe disposal of wastewater and sludge in different areas of developing countries results in significant environmental pollution, particularly for groundwater, thus increasing the risk of waterborne diseases spreading. In this work, a two-phase anaerobic digestion process for post-treatment of partially acidified sewage sludge was investigated to evaluate its feasibility as a safe sludge disposal system. Pilot tests showed that an effective sludge stabilization can be achieved (total volatile solids content <65%, organic acid concentration <200 mg/L at flow rate = 50 L/d and hydraulic residence time = 18 d) as well as a relative low faecal coliform density (<1000 most probable number per g total solids), showing that land application of the sludge without restrictions is possible according to US Environmental Protection Agency criteria for safe sludge disposal. A biogas production as high as 390 L/d with a 60% methane content by volume was achieved, showing that energy production from biogas may be achieved as well.

PLANNING AND ASSESSMENT MEASURES TO UPDATING RESOURCES RECYCLING EQUIPMENTS IN COLLABORATION WITH SEWAGE TREATMENT PLANTS AND WASTE INCINERATION PLANTS

NASA Astrophysics Data System (ADS)

Nakakubo, Toyohiko; Tokai, Akihiro; Ohno, Koichi

This study aims to assess two biomass utilization policies: the integration of food waste treatment in a sewerage treatment plant with an anaerobic digestion tank, and the pruned branch usage as heat source for drying sludge. We focused on two points in our analysis that the impact of the increase of dewatered sludge on sludge treatment processes after digestion and the improvement of the efficiency of waste power generation plants. A developed model was applied to the case study in Kobe city and evaluated the impact until 2030 by four indicators: energy consumption, greenhouse gas (GHG) emission, phosphorus-recovery, and cost. The results showed that case 3-C, which introducing the combined sludge and food waste digestion system, pyrolysis gasification with gas engine and wood-chip boiler, could supply additional 452 TJ/y of energy, recovery 93 t-P/y of phosphorus, and reduce 38 kt-CO2eq./y of GHG while shrinking the cost by 88 million yen/y compared to business as usual types-update case.

Presence of radionuclides in sludge from conventional drinking water treatment plants. A review.

PubMed

Fonollosa, E; Nieto, A; Peñalver, A; Aguilar, C; Borrull, F

2015-03-01

The analysis of sludge samples generated during water treatment processes show that different radioisotopes of uranium, thorium and radium, among others can accumulate in that kind of samples, even the good removal rates obtained in the aqueous phase (by comparison of influent and effluent water concentrations). Inconsequence, drinking water treatment plants are included in the group of Naturally Occurring Radioactive Material (NORM) industries. The accumulation of radionuclides can be a serious problem especially when this sludge is going to be reused, so more exhaustive information is required to prevent the possible radiological impact of these samples in the environment and also on the people. The main aim of this review is to outline the current situation regarding the different studies reported in the literature up to date focused on the analysis of the radiological content of these sludge samples from drinking water treatment plants. In this sense, special attention is given to the recent approaches for their determination. Another important aim is to discuss about the final disposal of these samples and in this regard, sludge reuse (including for example direct agricultural application or also as building materials) are together with landfilling the main reported strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Amelioration effects of wastewater sludge biochars on red soil acidity and their environmental risk].

PubMed

Lu, Zai-Liang; Li, Jiu-Yu; Jiang, Jun; Xu, Ren-Kou

2012-10-01

Biochars were prepared from wastewater sludge from two wastewater treatment plants in Nanjing using a pyrolysis method at 300, 500 and 700 degrees C. The properties of the biochars were measured, and their amelioration effects on the acidity of a red soil and environmental risk of application of sludge biochars were examined to evaluate the possibility of agricultural application of wastewater sludge biochars in red soils. Results indicated that incorporation of both sludge and sludge biochar increased soil pH due to the alkalinity of sludge and sludge biochar, and the mineralization of organic N and nitrification of ammonium N from wastewater sludge induced soil pH fluctuated during incubation. The amelioration effects of biochars generated at 500 and 700 degrees C on the soil were significantly greater than that of sludge significantly. Sludge and sludge biochar contain ample base cations of Ca2+, Mg2+, K+ and Na+ and thus incorporation of sludge and sludge biochar increased the contents of soil exchangeable base cations and decreased soil exchangeable aluminum and H+. Contents of heavy metals in sludge biochars were greater than these in their feedstock sludge, while the contents of Cu, Pb, Ni and As in sludge biochars were lower than the standard values of heavy metals were wastewater sludge for agricultural use in acid soils in China except for Zn and Cd. The contents of available forms of heavy metals in the biochars generated from sludge from Chengdong wastewater treatment plant was lower than these in the corresponding sludge, suggesting that pyrolysis proceed decreased the activity of heavy metals in wastewater sludge. After 90-day incubation of the soil with sludge and sludge biochar, the differences in the contents of soil available heavy metals were not significant between the biochars and their feedstock sludge from Jiangxizhou wastewater treatment plant, and the contents in the treatments with biochars added was lower than these in the treatments with the corresponding sludge from Chengdong wastewater treatment plant for most of heavy metals. It can be concluded that the biochars from wastewater sludge could be used as soil amendments to adjust soil acidity. Application of sludge biochars did not increase activity and availability of heavy metals compared with direct incorporation of the sludge.

Use of PCR-DGGE Based Molecular Methods to Analyse Microbial Community Diversity and Stability during the Thermophilic Stages of an ATAD Wastewater Sludge Treatment Process as an Aid to Performance Monitoring

PubMed Central

Piterina, Anna V.; Pembroke, J. Tony

2013-01-01

PCR and PCR-DGGE techniques have been evaluated to monitor biodiversity indexes within an ATAD (autothermal thermophilic aerobic digestion) system treating domestic sludge for land spread, by examining microbial dynamics in response to elevated temperatures during treatment. The ATAD process utilises a thermophilic population to generate heat and operates at elevated pH due to degradation of sludge solids, thus allowing pasteurisation and stabilisation of the sludge. Genera-specific PCR revealed that Archaea, Eukarya and Fungi decline when the temperature reaches 59°C, while the bacterial lineage constitutes the dominant group at this stage. The bacterial community at the thermophilic stage, its similarity index to the feed material, and the species richness present were evaluated by PCR-DGGE. Parameters such as choice of molecular target (16S rDNA or rpoB genes), and electrophoresis condition, were optimised to maximise the resolution of the method for ATAD. Dynamic analysis of microbial communities was best observed utilising PCR-DGGE analysis of the V6-V8 region of 16S rDNA, while rpoB gene profiles were less informative. Unique thermophilic communities were shown to quickly adapt to process changes, and shown to be quite stable during the process. Such techniques may be used as a monitoring technique for process health and efficiency. PMID:25937969

Energy saving control strategies for Haliscomenobacter hydrossis filamentous sludge bulking in the A/O process treating real low carbon/nitrogen domestic wastewater.

PubMed

Jiao, Erlong; Gao, Chundi; Li, Renfei; Tian, Ye; Peng, Yongzhen

2017-07-16

The control strategies of energy saving for filamentous sludge bulking were investigated in the A/O process under low dissolved oxygen (DO) with low carbon/nitrogen (C/N) ratio, and the dominant filamentous bacteria were identified by using fluorescent in situ hybridization. Initially, the sludge volume index reached nearly 500 mL/g and serious bulking occurred when the DO value was 0.5 mg/L, with Haliscomenobacter hydrossis as the major filamentous bacteria in the bulking sludge. Later on, the compartment number increased in the aerobic zone, increasing by this way DO, to control serious bulking. Increasing DO to 1 mg/L based on the increase of compartment number in the aerobic zone was the favorable controlling method, which solved the sludge loss, improved the effluent quality to the national discharge standard and allowed for energy costs saving. As a result, the effective control method for H. hydrossis filamentous sludge bulking provided the economical, convenient and longstanding method for most municipal wastewater treatment plants treating real low C/N domestic wastewater.

Recycling and reuse: Are they the answer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-11-01

At a time when reuse is widely recognized as a partial solution to the US mounting waste problem, it comes as no surprise that drinking water suppliers are giving thought to reclaiming residuals. This reuse may occur within the treatment plant, for example, by recovering alum from sludge or recycling waste streams, or outside the plant, where endeavors such as controlled land application return components of sludge to the soil. By nature, sludges and other residuals likely contain contaminants that have been removed from the water--e.g., Giardia and Cryptosporidium, trihalomethane precursors, and heavy metals. Recycling waste flows has the potentialmore » to disturb the treatment process or to affect the quality of finished water. Proper treatment and monitoring of waste streams can render them acceptable for recycling.« less

Micropollutant and sludge characterization for modeling sorption equilibria.

PubMed

Barret, Maialen; Carrère, Hélène; Latrille, Eric; Wisniewski, Christelle; Patureau, Dominique

2010-02-01

The sorption of hydrophobic micropollutants in sludge is one of the major mechanisms which drive their fate within wastewater treatment systems. The objective of this study was to investigate the influence of both sludge and micropollutant characteristics on the equilibria of sorption to particles and to dissolved and colloidal matter (DCM). For this purpose, the equilibrium constants were measured for 13 polycyclic aromatic hydrocarbons, 5 polychlorobiphenyls and the nonylphenol, and five different sludge types encountered in treatment systems: a primary sludge, a secondary sludge, the same secondary sludge after thermal treatment, after anaerobic digestion, and after both treatments. After thermal treatment, no more sorption to DCM was observed. Anaerobic biological treatment was shown to enhance micropollutants sorption to particles and to DCM of one logarithmic unit, due to matter transformation. Partial least-squares linear regressions of sorption data as a function of micropollutant and sludge properties revealed that sludge physical and chemical characteristics were more influential than micropollutant characteristics. Two models were provided to predict the sorption of such micropollutants in any sludge. To our knowledge, this is the first time that a three-compartment approach is used to accurately model micropollutant sorption in sludge and to understand the driving mechanisms.

Pattern of multiresistant to antimicrobials and heavy metal tolerance in bacteria isolated from sewage sludge samples from a composting process at a recycling plant in southern Brazil.

PubMed

Heck, Karina; De Marco, Évilin Giordana; Duarte, Mariana Wanderlei; Salamoni, Sabrina Pinto; Van Der Sand, Sueli

2015-06-01

The composting process is a viable alternative for the recycling of household organic waste and sewage sludge generated during wastewater treatment. However, this technique can select microorganisms resistant to antimicrobials and heavy metals as a result of excess chemicals present in compost windrow. This study evaluates the antimicrobial multiresistant and tolerance to heavy metals in bacteria isolated from the composting process with sewage sludge. Fourteen antimicrobials were used in 344 strains for the resistance profile and four heavy metals (chromium, copper, zinc, and lead) for the minimum biocide concentration assay. The strains used were from the sewage sludge sample (beginning of the process) and the compost sample (end of the process). Strains with higher antimicrobial and heavy metal profile were identified by 16S rRNA gene sequencing. The results showed a multiresistant profile in 48 % of the strains, with the highest percentage of strains resistant to nitrofurantoin (65 %) and β-lactams (58 %). The strains isolated from the sewage sludge and the end of the composting process were more tolerant to copper, with a lethal dose of approximately 900 mg L(-1) for about 50 % of the strains. The genera that showed the highest multiresistant profile and increased tolerance to the metals tested were Pseudomonas and Ochrobactrum. The results of this study may contribute to future research and the revision and regulation of legislation on sewage sludge reuse in soils.

Degradation of typical N-nitrosodimethylamine (NDMA) precursors and its formation potential in anoxic-aerobic (AO) activated sludge system.

PubMed

Wang, Lin; Li, Yongmei; He, Guodong

2014-01-01

N-nitrosodimethylamine (NDMA) is an emerging disinfection byproduct. Removal of its potential precursors is considered as an effective method to control NDMA. In this study, four typical NDMA precursors (dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB)) were selected, and their removal capacities by activated sludge were investigated. Batch experiments indicated that removal of NDMA precursors was better under aerobic condition than anoxic condition; and their specific degradation rates follow the order of DMA > TMA > DMFA > DMAB. In anoxic-aerobic (AO) activated sludge system, the optimal hydraulic retention time and sludge retention time were 10 h and 20 d, respectively, for the removal of both NDMA precursors (four selected NDMA precursors and NDMA formation potential (NDMA FP)) and nutrients. Our results also suggested that there was a positive correlation between NDMA FP and dissolved organic nitrogen (DON) in wastewater. The removal efficiency of NDMA FP was in the range of 46.8-72.5% in the four surveyed wastewater treatment plants except the one which adopted chemically enhanced primary process. The results revealed that the AO system had the advantage of removing NDMA FP. Our results are helpful for the knowledge of the removals of NDMA precursors during activated sludge treatment processes.

Effect of activated sludge acclimation aeration time on bayberry wastewater

NASA Astrophysics Data System (ADS)

Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

Taking the myrica rubra pickle wastewater of Chaozhou Kang Hui group as the water sample, biochemical method was used to treat the wastewater, after domestication, the biochemical treatment was carried out. The influence of time on COD index was investigated. The results showed that: tap water: sewage: sludge = 1:1:1, 900 mL each. Under the action of 30 min time, the supernatant was taken at 100 mL, and the wastewater was added to 900 mL,. Under the action of activated sludge, the degradation of myrica rubra wastewater samples, after domestication 84 h, the effect is better. Under this condition, the standard of SBR process for wastewater treatment is reached.

Microcosm assays and Taguchi experimental design for treatment of oil sludge containing high concentration of hydrocarbons.

PubMed

Castorena-Cortés, G; Roldán-Carrillo, T; Zapata-Peñasco, I; Reyes-Avila, J; Quej-Aké, L; Marín-Cruz, J; Olguín-Lora, P

2009-12-01

Microcosm assays and Taguchi experimental design was used to assess the biodegradation of an oil sludge produced by a gas processing unit. The study showed that the biodegradation of the sludge sample is feasible despite the high level of pollutants and complexity involved in the sludge. The physicochemical and microbiological characterization of the sludge revealed a high concentration of hydrocarbons (334,766+/-7001 mg kg(-1) dry matter, d.m.) containing a variety of compounds between 6 and 73 carbon atoms in their structure, whereas the concentration of Fe was 60,000 mg kg(-1) d.m. and 26,800 mg kg(-1) d.m. of sulfide. A Taguchi L(9) experimental design comprising 4 variables and 3 levels moisture, nitrogen source, surfactant concentration and oxidant agent was performed, proving that moisture and nitrogen source are the major variables that affect CO(2) production and total petroleum hydrocarbons (TPH) degradation. The best experimental treatment yielded a TPH removal of 56,092 mg kg(-1) d.m. The treatment was carried out under the following conditions: 70% moisture, no oxidant agent, 0.5% of surfactant and NH(4)Cl as nitrogen source.

Fate of Zinc Oxide Nanoparticles during Anaerobic Digestion of Wastewater and Post-Treatment Processing of Sewage Sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lombi, Enzo; Donner, Erica; Tavakkoli, Ehsan

2013-01-14

The rapid development and commercialization of nanomaterials will inevitably result in the release of nanoparticles (NPs) to the environment. As NPs often exhibit physical and chemical properties significantly different from those of their molecular or macrosize analogs, concern has been growing regarding their fate and toxicity in environmental compartments. The wastewater-sewage sludge pathway has been identified as a key release pathway leading to environmental exposure to NPs. In this study, we investigated the chemical transformation of two ZnO-NPs and one hydrophobic ZnO-NP commercial formulation (used in personal care products), during anaerobic digestion of wastewater. Changes in Zn speciation as amore » result of postprocessing of the sewage sludge, mimicking composting/stockpiling, were also assessed. The results indicated that 'native' Zn and Zn added either as a soluble salt or as NPs was rapidly converted to sulfides in all treatments. The hydrophobicity of the commercial formulation retarded the conversion of ZnO-NP. However, at the end of the anaerobic digestion process and after postprocessing of the sewage sludge (which caused a significant change in Zn speciation), the speciation of Zn was similar across all treatments. This indicates that, at least for the material tested, the risk assessment of ZnO-NP through this exposure pathway can rely on the significant knowledge already available in regard to other 'conventional' forms of Zn present in sewage sludge.« less

Reuse of residual sludge from stone-processing: differences and similarities between sludge coming from carbonate and silicate stones

NASA Astrophysics Data System (ADS)

Careddu, Nicola; Antonella Dino, Giovanna

2015-04-01

Residual sludge coming from dimension stone working activities represents a serious environmental and economic problem both for Stone Industry and citizens. Indeed, most of time, residual sludge is landfilled because of the difficulties to recover it; such difficulties are mainly connected to local legislation and a lack of proper protocols. In general, it is possible to individuate two different categories of sludge: residual sludge coming from carbonate rocks (CS) and those coming from silicate rocks (SS). Both of them are characterised by a very fine size distribution. CS is composed mainly by the same compounds of the processed stones (marble, limestone, travertine). The reason of this is related to the very slow wear of diamond tools during processing which entails a negligible content of heavy metals. CS becomes very interesting, from an economic point of view, when it has a CaCO3 grade > 95 %. On the contrary, SS is characterised by high heavy metal and TPH content. Residual sludge from the processing of silicate rocks can be split in three different sub-categories, depending on the way they are produced, and in particular: sludge from gangsaw using abrasive steel shot (GSS), sludge from multi diamond-saw block cutter (DBC), and mixed sludge (MS) from gangsaw and block cutter. These three sub-categories show different problems connected to heavy metal content, indeed on the one hand GSS is characterised by a high percentage of Ni, Cr, Cu, etc., on the other hand DBC is characterised by Co and Cu high content. In general, sludge, management of which in Italy is administered in accordance with the Italian Legislative Decree 152/06, can be used as waste from for environmental restoration or for cement plants. Several researches investigate the possible reuse of these materials but, at present time, there is no evidence of its systematic recovery as "recycled product" or "by-product". On the basis of the results of these researches it is possible to highlight its recovery, after a proper treatment, mainly as: landfill waterproofing material; filler material for civil works; artificial soil for land rehabilitation and high value added products from carbonate rocks. Such "new products", obtained from the treatment of residual sludge, have to be certified not only on the basis of their technical and physical characteristics but also by means of appropriate chemical analyses to guarantee that the products are not polluted. The research will show a comparison between the characteristics of the two main sludge categories (similarities and differences), the environmental problems connected to sludge management, the potential applications for both the categories (CS and SS), highlighting the most promising ones (e.g., SS: artificial soil for land rehabilitation and filler material for civil works; CS: filler in high value added products as paper, rubber and paints), the problems connected to "new products" certification and selling, and some suggestions for executive protocols to boost their systematic recovery.

Sewage sludge open-air drying affects on keratinolytic, keratinophilic and actidione-resistant fungi.

PubMed

Ulfig, Krzysztof; Płaza, Grazyna; Terakowskip, Maciej; Janda-Ulfig, Katarzyna

2006-01-01

The study was to demonstrate the effect of sewage sludge open-air drying on the quantitative and qualitative composition of keratinolytic/keratinophilic and actidione-resistant fungi. The sludge was being dried for up to thirty days (on average fourteen days) at 25-30'C. The composition of these fungi was determined with the hair baiting method along with the dilution method, using the Wiegand medium supplemented with chloramphenicol (100 mgiL) and actidione (500 mg/L). The open-air drying altered the composition of keratinolytic fungi and considerably increased the population of keratinophilic and actidione-resistant fungi in the sludge. This phenomenon can be explained with that the drying process was associated with slow sludge moisture decrease, sludge laceration due to crumbling and the subsequent improvement of sludge aeration and organic matter biodegradation conditions. A considerable increase of fungal populations can be expected in sludges being dried in drying beds at wastewater treatment plants and in sludge-amended soils. Two sludge opportunistic fungi, i.e. Microsporum gypseum and Pseudallescheria boydii, require special attention from the epidemiological point of view. Sludge land applications may increase the number of these fungi in the environment and the subsequent risk to public health posed by them.

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

NASA Astrophysics Data System (ADS)

Żubrowska-Sudoł, Monika; Podedworna, Jolanta; Bisak, Agnieszka; Sytek-Szmeichel, Katarzyna; Krawczyk, Piotr; Garlicka, Agnieszka

2017-11-01

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9%) and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Risk assessments of polybrominated diphenyl ethers (PBDEs) during sludge application in China

NASA Astrophysics Data System (ADS)

Qian, Jun

2018-02-01

Due to increasingly less space in municipal environment, waste management has become an urgent issue worldwide. As one of common municipal waste, sewage sludge from wastewater treatment plants (WWTPs) contains abundant nutrients, some of which can be quite essential for plant growth. In consideration of nutrient recycling and energy saving, sludge application has been frequently promoted in many countries across the world. However, even after several sludge stabilization procedures, sewage sludge may still contain a large variety of toxic pollutants, especially some emerging organic contaminants (EOCs). Applied in various household products and plastic industries as additives, polybrominated diphenyl ethers (PBDEs) have been constantly detected in sewage sludge samples from several cities in China since 2005, as well as some biosolid samples after sludge stabilization processes, suggesting their strong persistence and wide occurrence. During sludge application onto farmland soils, PBDEs may desorb from sludge particles and get attached by soil organic matter (SOM), followed by plant root uptake and translocation to aboveground tissues. In this study, data about current pollution of PBDEs in sewage sludge samples from China was reviewed, and the potential risks during sludge application was comprehensively assessed.

Sewage sludge disintegration by combined treatment of alkaline+high pressure homogenization.

PubMed

Zhang, Yuxuan; Zhang, Panyue; Zhang, Guangming; Ma, Weifang; Wu, Hao; Ma, Boqiang

2012-11-01

Alkaline pretreatment combined with high pressure homogenization (HPH) was applied to promote sewage sludge disintegration. For sewage sludge with a total solid content of 1.82%, sludge disintegration degree (DD(COD)) with combined treatment was higher than the sum of DD(COD) with single alkaline and single HPH treatment. NaOH dosage ⩽0.04mol/L, homogenization pressure ⩽60MPa and a single homogenization cycle were the suitable conditions for combined sludge treatment. The combined sludge treatment showed a maximum DD(COD) of 59.26%. By regression analysis, the combined sludge disintegration model was established as 11-DD(COD)=0.713C(0.334)P(0.234)N(0.119), showing that the effect of operating parameters on sludge disintegration followed the order: NaOH dosage>homogenization pressure>number of homogenization cycle. The energy efficiency with combined sludge treatment significantly increased compared with that with single HPH treatment, and the high energy efficiency was achieved at low homogenization pressure with a single homogenization cycle. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determining organic pollutants in automotive industry sludge.

PubMed

Munaretto, Juliana S; Wonghon, Audrey L; von Mühlen, Carin

2012-12-01

In Brazil, the policy for disposing industrial sludge is changing from an emphasis on using controlled landfills to other treatment or co-processing methods; however, the monitoring of organic pollutants is not mandatory. The present study evaluated two general screening methods for organic pollutants in sludge generated in an automotive industrial complex in southern Brazil. The screening was performed using Soxhlet and sonication extractions and Gas Chromatograph coupled with Quadrupole Mass Spectrometry (GC/qMS). It was concluded that both techniques were effective and that most of the compounds identified were alkanes, phenols and esters. Important pollutants were detected in the sludge, which confirms the necessity of monitoring this type of residue.

Sorption and Release of Organics by Primary, Anaerobic, and Aerobic Activated Sludge Mixed with Raw Municipal Wastewater

PubMed Central

Modin, Oskar; Saheb Alam, Soroush; Persson, Frank; Wilén, Britt-Marie

2015-01-01

New activated sludge processes that utilize sorption as a major mechanism for organics removal are being developed to maximize energy recovery from wastewater organics, or as enhanced primary treatment technologies. To model and optimize sorption-based activated sludge processes, further knowledge about sorption of organics onto sludge is needed. This study compared primary-, anaerobic-, and aerobic activated sludge as sorbents, determined sorption capacity and kinetics, and investigated some characteristics of the organics being sorbed. Batch sorption assays were carried out without aeration at a mixing velocity of 200 rpm. Only aerobic activated sludge showed net sorption of organics. Sorption of dissolved organics occurred by a near-instantaneous sorption event followed by a slower process that obeyed 1st order kinetics. Sorption of particulates also followed 1st order kinetics but there was no instantaneous sorption event; instead there was a release of particles upon mixing. The 5-min sorption capacity of activated sludge was 6.5±10.8 mg total organic carbon (TOC) per g volatile suspend solids (VSS) for particulate organics and 5.0±4.7 mgTOC/gVSS for dissolved organics. The observed instantaneous sorption appeared to be mainly due to organics larger than 20 kDa in size being sorbed, although molecules with a size of about 200 Da with strong UV absorbance at 215–230 nm were also rapidly removed. PMID:25768429

Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method.

PubMed

Meusel, S; Englert, R

2004-01-01

This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depth-dependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a one-litre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.

Wastewater and sludge management and research in Oman: An overview.

PubMed

Jaffar Abdul Khaliq, Suaad; Ahmed, Mushtaque; Al-Wardy, Malik; Al-Busaidi, Ahmed; Choudri, B S

2017-03-01

It is well recognized that management of wastewater and sludge is a critical environmental issue in many countries. Wastewater treatment and sludge production take place under different technical, economic, and social contexts, thus requiring different approaches and involving different solutions. In most cases, a regular and environmentally safe wastewater treatment and associated sludge management requires the development of realistic and enforceable regulations, as well as treatment systems appropriate to local circumstances. The main objective of this paper is to provide useful information about the current wastewater and sludge treatment, management, regulations, and research in Oman. Based on the review and discussion, the wastewater treatment and sludge management in Oman has been evolving over the years. Further, the land application of sewage sludge should encourage revision of existing standards, regulations, and policies for the management and beneficial use of sewage sludge in Oman. Wastewater treatment and sludge management in Oman have been evolving over the years. Sludge utilization has been a challenge due to its association with human waste. Therefore, composting of sewage sludge is the best option in agriculture activities. Sludge and wastewater utilization can add up positively in the economic aspects of the country in terms of creating jobs and improving annual income rate. The number of research projects done on wastewater reuse and other ongoing ones related to the land application of sewage sludge should encourage revision of existing standards, regulations, and policies for the management and beneficial use of sewage sludge in Oman.

Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

PubMed

Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

2013-01-01

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

Stabilization of industry sludge by composting for use as an organic fertilizer

NASA Astrophysics Data System (ADS)

Elia Ruda, Ester; Mercedes Ocampo, Ester; Acosta, Adriana; Mongiello, Adriana; Olmos, Graciela

2013-04-01

The effluent treatment plant having PBLEINER SA food industry produces sludge coming from aerobic treatment reactors. The research team FIQ-UNL evaluated the feasibility of their use for the production of organic fertilizers as part of an environmental management problem to reduce the volume of sludge to be moved to land farming located more than 300 km of the plant. The mean values of the variables analyzed in the sludge were the following: carbon: 23.7 %, nitrogen: 7.83 %, pH: 7.36, bulk density: 0.722 g.cm-3, actual density: 1.76 g.cm-3, porosity: 50.7 %, potassium: 0.242 %, phosphorus: 1.29 %, calcium: 1.84 %, magnesium: 0.364 % and electrical conductivity: 3.51 dS.m-1 (25 °C). The content of heavy metals in sludge is much lower than the limits set by the European Union, USEPA and SENASA for use in agriculture. The mean values of the metals analyzed in the sludge were the following: cadmium: no detected, lead: 18.7 mg.kg-1, zinc 213 mg.kg-1, copper: 40.7 mg.kg-1, nickel: 110 mg.kg-1, chrome: 406 mg.kg-1, mercury: 1.53 mg.kg-1. In this framework it was proposed stabilization of sludge by composting, using sawdust or chips as stabilizing material, with aeration technique in rows with frequent turning and recycling leachate, so as to degrade organic solids humic material for application as a soil conditioner, this is for transformation into a new product to be used as fertilizer. The company provided the physical space and technical staff to assist the research team. This process design is a proposal to improve the waste treatment of an industrial plant, reducing its environmental impact and enabling the use of the resulting product for soil enhancement in the region. Optimizing operating parameters such as kinetics, moisture, temperature, pH, total dissolved solids, nutrient availability, alternative sources of carbon and processing steps, will allow obtaining technical data for the modelling process.

Tracing pharmaceuticals in a municipal plant for integrated wastewater and organic solid waste treatment.

PubMed

Jelic, Aleksandra; Fatone, Francesco; Di Fabio, Silvia; Petrovic, Mira; Cecchi, Franco; Barcelo, Damia

2012-09-01

The occurrence and removal of 42 pharmaceuticals, belonging to different therapeutic groups (analgesics and anti-inflammatory drugs, anti-ulcer agent, psychiatric drugs, antiepileptic drug, antibiotics, ß-blockers, diuretics, lipid regulator and cholesterol lowering statin drugs and anti-histamines), were studied in the wastewater and sewage sludge trains of a full scale integrated treatment plant. The plant employs a biological nutrient removal (BNR) process for the treatment of municipal wastewater, and a single-stage mesophilic anaerobic co-digestion for the treatment of wasted activated sludge mixed with the organic fraction of municipal solid waste (OFMSW), followed by a short-cut nitrification-denitrification of the anaerobic supernatant in a sequential batch reactor. Influent and effluent wastewater, as well as thickened, digested and treated sludge were sampled and analyzed for the selected pharmaceuticals in order to study their presence and fate during the treatment. Twenty three compounds were detected in influent and effluent wastewater and eleven in sludge. Infiltration of groundwater in the sewer system led to a dilution of raw sewage, resulting in lower concentrations in wastewater (up to 0.7 μg/L in influent) and sludge (70 ng/g d.w.). Due to the dilution, overall risk quotient for the mixture of pharmaceuticals detected in effluent wastewater was less than one, indicating no direct risk for the aquatic environment. A wide range of removal efficiencies during the treatment was observed, i.e. <20% to 90%. The influent concentrations of the target pharmaceuticals, as polar compounds, were undoubtedly mostly affected by BNR process in the wastewater train, and less by anaerobic-co-digestion. Mass balance calculations showed that less than 2% of the total mass load of the studied pharmaceuticals was removed by sorption. Experimentally estimated distribution coefficients (<500 L/kg) also indicated that the selected pharmaceuticals preferably remain in the aqueous phase, and that biodegradation/transformation is the primary removal mechanism for these compounds during wastewater treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

Investigations into Improving Dewaterability at a Bio-P/Anaerobic Digestion Plant.

PubMed

Alm, Rebecca; Sealock, Adam W; Nollet, Yabing; Sprouse, George

2016-11-01

  Metropolitan Council Environmental Services has observed poorer than expected dewatering performance at its Empire Plant. This plant has both anaerobic digestion and enhanced biological phosphorus removal in its treatment train. A research program using pilot-scale anaerobic digesters investigated potential solutions to the plant's poor dewaterability. The dewaterability goal was to increase the cake solids from 12% total solids (TS) to 16% TS or higher. This research investigated 20 different reactor conditions including chemical, feed sludge, and digested sludge treatments. At the pilot scale, unaerated storage of waste activated sludge prior to thickening and addition of ferric chloride to digestion was found to achieve dewatered cake solids of nearly 17% TS with the added benefit of reducing polymer demand. Issues including the amount of chemical required and the resulting volatile solids destruction influence the viability of the process change, so a full-scale pilot and financial analysis is recommended before making permanent process changes.

Sewage sludge pasteurization by gamma radiation: Financial viability case studies

NASA Astrophysics Data System (ADS)

Swinwood, Jean F.; Kotler, Jiri

This paper examines the financial viability of sewage sludge pasteurization by gamma radiation, by examining the following three North American scenarios: 1) Small volume sewage treatment plant experiencing high sludge disposal costs. 2) Large volume sewage treatment plant experiencing low sludge disposal costs. 3) Large volume sewage treatment plant experiencing high sludge disposal costs.

Influence of operational conditions on the performance of a mesh filter activated sludge process.

PubMed

Fuchs, W; Resch, C; Kernstock, M; Mayer, M; Schoeberl, P; Braun, R

2005-03-01

Recently, a new type of wastewater treatment system became the focus of scientific research, the mesh filter activated sludge system. It is a modification of the membrane bioreactor where a membrane filtration process serves to separate the sludge from the purified effluent. The difference is that a mesh filter is used instead of the membrane. Due to the much larger pore size of the mesh, the effluent is not of the same excellent quality as with membrane bioreactors. Nevertheless, it still resembles the quality of the now most widely used standard treatment system, where settling tanks are used to retain the activated sludge. At the same time, the new system features all the other advantages of membrane bioreactors including elevated sludge concentrations resulting in decreased volumina of basins and complete substitution of the settling tank. Therefore, this process presents a potential future alternative where a small footprint of the plant is required. However, so far only a few preliminary studies on this innovative process type have been done. In this paper, the effects of suspended solids concentration, flux rate as well as aeration rate on the effluent quality are discussed. Furthermore, the characteristic of the sludge floc was identified as a factor of vital importance. Therefore, another influencing parameter, the food to microorganism (F/M) ratio, which is known to have a significant effect on floc characteristics, was studied. The main result demonstrated that the process was very effective under most of the operation conditions. The suspended solids concentration in the effluent was below 12 mg l(-1), the average COD in the effluent was between 24 and 45 mg l(-1) and the BOD(5) was lower than 5 mg l(-1). High flux rates of up to 150 l m(-2)h(-1) were also achieved.

Fenton mediated ultrasonic disintegration of sludge biomass: Biodegradability studies, energetic assessment, and its economic viability.

PubMed

Kavitha, S; Rajesh Banu, J; IvinShaju, C D; Kaliappan, S; Yeom, Ick Tae

2016-12-01

Mechanical disintegration of sludge through ultrasonication demands high energy and cost. Therefore, in the present study, a comprehensive investigation was performed to analyze the potential of a novel method, fenton mediated sonic disintegration (FSD). In FSD process, extracellular polymeric substance (EPS) of sludge was first removed via fenton treatment. It was subsequently disintegrated via ultrasonication. Energetic assessment and economic analysis were then performed using net energy and cost gain (spent) as key factor to evaluate the practical viability of the FSD process. FSD was found to be superior over sonic disintegration based on its higher sludge solubilization (34.4% vs. 23.2%) and methane production potential (0.3gCOD/gCOD vs. 0.2gCOD/gCOD). Both energy analysis and cost assessment of the present study revealed that FSD could reduce the energy demand of ultrasonication considerably with a positive net profit of about 44.93USD/Ton of sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Ultrasonic Multi-Beam Concentration Meter with a Neuro-Fuzzy Algorithm for Water Treatment Plants

PubMed Central

Lee, Ho-Hyun; Jang, Sang-Bok; Shin, Gang-Wook; Hong, Sung-Taek; Lee, Dae-Jong; Chun, Myung Geun

2015-01-01

Ultrasonic concentration meters have widely been used at water purification, sewage treatment and waste water treatment plants to sort and transfer high concentration sludges and to control the amount of chemical dosage. When an unusual substance is contained in the sludge, however, the attenuation of ultrasonic waves could be increased or not be transmitted to the receiver. In this case, the value measured by a concentration meter is higher than the actual density value or vibration. As well, it is difficult to automate the residuals treatment process according to the various problems such as sludge attachment or sensor failure. An ultrasonic multi-beam concentration sensor was considered to solve these problems, but an abnormal concentration value of a specific ultrasonic beam degrades the accuracy of the entire measurement in case of using a conventional arithmetic mean for all measurement values, so this paper proposes a method to improve the accuracy of the sludge concentration determination by choosing reliable sensor values and applying a neuro-fuzzy learning algorithm. The newly developed meter is proven to render useful results from a variety of experiments on a real water treatment plant. PMID:26512666

An Ultrasonic Multi-Beam Concentration Meter with a Neuro-Fuzzy Algorithm for Water Treatment Plants.

PubMed

Lee, Ho-Hyun; Jang, Sang-Bok; Shin, Gang-Wook; Hong, Sung-Taek; Lee, Dae-Jong; Chun, Myung Geun

2015-10-23

Ultrasonic concentration meters have widely been used at water purification, sewage treatment and waste water treatment plants to sort and transfer high concentration sludges and to control the amount of chemical dosage. When an unusual substance is contained in the sludge, however, the attenuation of ultrasonic waves could be increased or not be transmitted to the receiver. In this case, the value measured by a concentration meter is higher than the actual density value or vibration. As well, it is difficult to automate the residuals treatment process according to the various problems such as sludge attachment or sensor failure. An ultrasonic multi-beam concentration sensor was considered to solve these problems, but an abnormal concentration value of a specific ultrasonic beam degrades the accuracy of the entire measurement in case of using a conventional arithmetic mean for all measurement values, so this paper proposes a method to improve the accuracy of the sludge concentration determination by choosing reliable sensor values and applying a neuro-fuzzy learning algorithm. The newly developed meter is proven to render useful results from a variety of experiments on a real water treatment plant.

Characterization of Industrial Wastewater Sludge in Oman from Three Different Regions and Recommendations for Alternate Reuse Applications.

PubMed

Baawain, Mahad S; Al-Jabri, Mohsin; Choudri, B S

2015-11-01

Domestic and industrial wastewaters are mostly treated by biological process such as activated sludge, aerobic pond, and anaerobic treatment. This study focuses on characterizing the quality of sewage sludge in the Sultanate of Oman chosen from three industrial sewage treatment plants (STPs): Rusayl Industrial Estate (RSL.IE); Sohar Industrial Estate (SIE); and Raysut Industrial Estate (RIE). Samples of recycled activated sludge (RAS) and wasted activated sludge (WAS) were collected over a period of 12 months across above mentioned STPs. Parameters analyzed are electrical conductivity (EC), potential of hydrogen (pH), cations, anions and volatile content (VC). The obtained values for pH and EC were low for both RAS and WAS samples, except EC values of RIE that was more than 1000 μS/cm. The range of VC percentages in RAS and WAS samples were 44 to 86% and 41 to 77%, respectively. The measured values for chloride, sulfate, nitrate and phosphate were higher than the other anions. The average values of the cations in RAS and WAS samples were within the Omani Standards, suitable for the re-use of sludge in agriculture except for Cd in RSL.IE. The study recommends that a regular maintenance should be performed at the studied STPs to prevent any accumulation of some harmful substances, which may affect the sludge quality, and the sludge drying beds should be large enough to handle the produced sludge for better management.

Characterization of Industrial Wastewater Sludge in Oman from Three Different Regions and Recommendations for Alternate Reuse Applications

PubMed Central

BAAWAIN, Mahad S.; AL-JABRI, Mohsin; CHOUDRI, B.S.

2015-01-01

Background: Domestic and industrial wastewaters are mostly treated by biological process such as activated sludge, aerobic pond, and anaerobic treatment. This study focuses on characterizing the quality of sewage sludge in the Sultanate of Oman chosen from three industrial sewage treatment plants (STPs): Rusayl Industrial Estate (RSL.IE); Sohar Industrial Estate (SIE); and Raysut Industrial Estate (RIE). Methods: Samples of recycled activated sludge (RAS) and wasted activated sludge (WAS) were collected over a period of 12 months across above mentioned STPs. Parameters analyzed are electrical conductivity (EC), potential of hydrogen (pH), cations, anions and volatile content (VC). Results: The obtained values for pH and EC were low for both RAS and WAS samples, except EC values of RIE that was more than 1000 μS/cm. The range of VC percentages in RAS and WAS samples were 44 to 86% and 41 to 77%, respectively. The measured values for chloride, sulfate, nitrate and phosphate were higher than the other anions. Conclusion: The average values of the cations in RAS and WAS samples were within the Omani Standards, suitable for the re-use of sludge in agriculture except for Cd in RSL.IE. The study recommends that a regular maintenance should be performed at the studied STPs to prevent any accumulation of some harmful substances, which may affect the sludge quality, and the sludge drying beds should be large enough to handle the produced sludge for better management. PMID:26744704

Monitoring and optimizing the co-composting of dewatered sludge: a mixture experimental design approach.

PubMed

Komilis, Dimitrios; Evangelou, Alexandros; Voudrias, Evangelos

2011-09-01

The management of dewatered wastewater sludge is a major issue worldwide. Sludge disposal to landfills is not sustainable and thus alternative treatment techniques are being sought. The objective of this work was to determine optimal mixing ratios of dewatered sludge with other organic amendments in order to maximize the degradability of the mixtures during composting. This objective was achieved using mixture experimental design principles. An additional objective was to study the impact of the initial C/N ratio and moisture contents on the co-composting process of dewatered sludge. The composting process was monitored through measurements of O(2) uptake rates, CO(2) evolution, temperature profile and solids reduction. Eight (8) runs were performed in 100 L insulated air-tight bioreactors under a dynamic air flow regime. The initial mixtures were prepared using dewatered wastewater sludge, mixed paper wastes, food wastes, tree branches and sawdust at various initial C/N ratios and moisture contents. According to empirical modeling, mixtures of sludge and food waste mixtures at 1:1 ratio (ww, wet weight) maximize degradability. Structural amendments should be maintained below 30% to reach thermophilic temperatures. The initial C/N ratio and initial moisture content of the mixture were not found to influence the decomposition process. The bio C/bio N ratio started from around 10, for all runs, decreased during the middle of the process and increased to up to 20 at the end of the process. The solid carbon reduction of the mixtures without the branches ranged from 28% to 62%, whilst solid N reductions ranged from 30% to 63%. Respiratory quotients had a decreasing trend throughout the composting process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Optimization of combined in-vessel composting process and chemical oxidation for remediation of bottom sludge of crude oil storage tanks.

PubMed

Koolivand, Ali; Naddafi, Kazem; Nabizadeh, Ramin; Saeedi, Reza

2017-07-31

In this research, removal of petroleum hydrocarbons from oily sludge of crude oil storage tanks was investigated under the optimized conditions of in-vessel composting process and chemical oxidation with H 2 O 2 and Fenton. After determining the optimum conditions, the sludge was pre-treated with the optimum state of the oxidation process. Then, the determined optimum ratios of the sludge to immature compost were composted at a C:N:P ratio of 100:5:1 and moisture content of 55% for a period of 10 weeks. Finally, both pre-treated and composted mixtures were again oxidized with the optimum conditions of the oxidants. Results showed that total petroleum hydrocarbons (TPH) removal of the 1:8 and 1:10 composting reactors which were pre-treated with H 2 O 2 were 88.34% and 90.4%, respectively. In addition, reduction of TPH in 1:8 and 1:10 composting reactors which were pre-treated with Fenton were 83.90% and 84.40%, respectively. Without applying the pre-treatment step, the composting reactors had a removal rate of about 80%. Therefore, pre-treatment of the reactors increased the TPH removal. However, post-oxidation of both pre-treated and composted mixtures reduced only 13-16% of TPH. Based on the results, remarkable overall removal of TPH (about 99%) was achieved by using chemical oxidation and subsequent composting process. The study showed that chemical oxidation with H 2 O 2 followed by in-vessel composting is a viable choice for the remediation of the sludge.

Continuous sulfidogenic wastewater treatment with iron sulfide sludge oxidation and recycle.

PubMed

Deng, Dongyang; Lin, Lian-Shin

2017-05-01

This study evaluated the technical feasibility of packed-bed sulfidogenic bioreactors dosed with ferrous chloride for continuous wastewater treatment over a 450-day period. In phase I, the bioreactors were operated under different combinations of carbon, iron, and sulfate mass loads without sludge recycling to identify optimal treatment conditions. A COD/sulfate mass ratio of 2 and a Fe/S molar ratio of 1 yielded the best treatment performance with COD oxidation rate of 786 ± 82 mg/(L⋅d), which resulted in 84 ± 9% COD removal, 94 ± 6% sulfate reduction, and good iron retention (99 ± 1%) under favorable pH conditions (6.2-7.0). In phase II, the bioreactors were operated under this chemical load combination over a 62-day period, during which 7 events of sludge collection, oxidation, and recycling were performed. The collected sludge materials contained both inorganic and organic matter with FeS and FeS 2 as the main inorganic constituents. In each event, the sludge materials were oxidized in an oxidizing basin before recycling to mix with the wastewater influent. Sludge recycling yielded enhanced COD removal (90 ± 6% vs. 75 ± 7%), and better effluent quality in terms of pH (6.8 ± 0.1 vs. 6.5 ± 0.2), iron (0.7 ± 0.5 vs. 1.9 ± 1.7 mg/L), and sulfide-S (0.3 ± 0.1 vs. 0.4 ± 0.1 mg/L) removal compared to the baseline operation without sludge recycling during phase II. This process exhibited treatment stability with reasonable variations, and fairly consistent sludge content over long periods of operation under a range of COD/sulfate and Fe/S ratios without sludge recycling. The bioreactors were found to absorb recycling-induced changes efficiently without causing elevated suspended solids in the effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of electron beam irradiation on bacterial and Ascaris ova loads and volatile organic compounds in municipal sewage sludge

NASA Astrophysics Data System (ADS)

Engohang-Ndong, Jean; Uribe, R. M.; Gregory, Roger; Gangoda, Mahinda; Nickelsen, Mike G.; Loar, Philip

2015-07-01

Wastewater treatment plants produce large amounts of biosolids that can be utilized for land applications. However, prior to their use, these biosolids must be treated to eliminate risks of infections and to reduce upsetting odors. In this study, microbiological and chemical analyzes were performed before and after treatment of sewage sludge with 3 MeV of an electron beam accelerator in a pilot processing plant. Thus, we determined that dose 4.5 kGy was required to reduce fecal coliform counts to safe levels for land applications of sludge while, 14.5 kGy was necessary to decrease Ascaris ova counts to safe levels. Furthermore, at low doses, electron beam irradiation showed little effect on the concentrations of volatile organic compounds, while some increase were recorded at high doses. The concentration of dimethyl sulfide was reduced by 50-70% at irradiation doses of 25.7 kGy and 30.7 kGy respectively. By contrast, electron beam irradiation increased dimethyl disulfide concentrations. We also showed that electron beam treatment was less energy-consuming with shorter processing times than conventional techniques used to decontaminate sludge. Hence opening new avenues for large urban agglomerations to save money and time when treating biosolids for land application.

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

CARRO CA

2011-07-15

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volumemore » of 5.2 m{sup 3} of KW Basin floor and pit sludge, 18.4 m{sup 3} of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m{sup 3} of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical characteristics can be found in HNF-41051, Preliminary STP Container and Settler Sludge Process System Description and Material Balance. In summary, the ECRTS retrieves sludge from the engineered containers and hydraulically transfers it as a slurry into an STSC positioned within a trailer-mounted STS cask located in a Modified KW Basin Annex. The slurry is allowed to settle within the STSC to concentrate the solids and clarify the supernate. After a prescribed settling period the supernate is decanted. The decanted supernate is filtered through a sand filter and returned to the basin. Subsequent batches of slurry are added to the STSC, settled, and excess supernate removed until the prescribed quantity of sludge is collected. The sand filter is then backwashed into the STSC. The STSC and STS cask are then inerted and transported to T Plant.« less

Combined ultrasound with Fenton treatment for the degradation of carcinogenic polycyclic aromatic hydrocarbons in textile dying sludge.

PubMed

Zhang, Jian-Hao; Zou, Hai-Yuan; Ning, Xun-An; Lin, Mei-Qing; Chen, Chang-Min; An, Tai-Cheng; Sun, Jian

2017-03-22

To develop an effective method to remove the toxic and carcinogenic polycyclic aromatic hydrocarbons (CPAHs) from textile dyeing sludge, five CPAHs were selected to investigate the degradation efficiencies using ultrasound combined with Fenton process (US/Fenton). The results showed that the synergistic effect of the US/Fenton process on the degradation of CPAHs in textile dyeing sludge was significant with the synergy degree of 30.4. During the US/Fenton process, low ultrasonic density showed significant advantage in degrading the CPAHs in textile dyeing sludge. Key reaction parameters on CPAHs degradation were optimized by the central composite design as followed: H 2 O 2 concentration of 152 mmol/L, ultrasonic density of 408 W/L, pH value of 3.7, the molar ratio of H 2 O 2 to Fe 2+ of 1.3 and reaction time of 43 min. Under the optimal conditions of the US/Fenton process, the degradation efficiencies of five CPAHs were obtained as 81.23% (benzo[a]pyrene) to 84.98% (benz[a]anthracene), and the benzo[a]pyrene equivalent (BaP eq ) concentrations of five CPAHs declined by 81.22-85.19%, which indicated the high potency of US/Fenton process for removing toxic CPAHs from textile dyeing sludge.

Biodegradation of phytosanitary products in biological wastewater treatment.

PubMed

Massot, A; Estève, K; Noilet, P; Méoule, C; Poupot, C; Mietton-Peuchot, M

2012-04-15

Agricultural activity generates two types of waste: firstly, biodegradable organic effluents generally treated by biological processes and, secondly, phytosanitary effluents which contain residues of plant protection products. The latter are collected and treated. Current technological solutions are essentially based on concentration or physical-chemical processes. However, recent improvements in the biodegradability of pesticides open the way to the consideration of alternative, biological, treatment using mixed liquor from wastewater plant activated sludge. The feasibility of the biological treatment of viticultural effluents has been evaluated by the application of pesticides to activated sludge. The necessity for selection of a pesticide-resistant biomass has been highlighted. The elimination of the phytosanitary products shows the potential of a resistant biomass in the treatment of pesticides. The aerated biological storage ponds at three wineries, followed by a sand or reed-bed filter, were used for the treatment of the total annual volume of the viticulture effluents and validate the laboratory experiments. The results show that the biological purification of pesticides by activated sludge is possible by allowing approximately 8 days for biomass adaptation. Stability of purification occurs between 20 and 30 days. Copyright © 2012 Elsevier Ltd. All rights reserved.

Toxicity of leather tanning wastewater effluents in sea urchin early development and in marine microalgae.

PubMed

Meriç, Süreyya; De Nicola, Elena; Iaccarino, Mario; Gallo, Marialuisa; Di Gennaro, Annamaria; Morrone, Gaetano; Warnau, Michel; Belgiorno, Vincenzo; Pagano, Giovanni

2005-10-01

This study was designed to investigate the composition and the toxicity of leather tanning wastewater and conditioned sludge collected at the leather tanning wastewater treatment plant (CODISO) located in Solofra, Avellino (Southern Italy). Samples were analyzed for their conventional parameters (COD, TSS, chromium and ammonia) and for metal content. Effluent samples included raw wastewater, and samples collected following coagulation/flocculation process and biological treatment. A set of toxicity endpoints were tested using sea urchin and marine microalgal bioassays by evaluating acute embryotoxicity, developmental defects, changes in sperm fertilization success and transmissible damage from sperm to the offspring, and changes in algal growth rate. Dose-related toxicity to sea urchin embryogenesis and sperm fertilization success was exerted by effluent or sludge samples according to the following rank: conditioned sludge > coagulated effluent > or = raw influent > effluent from biological treatment. Offspring quality was not affected by sperm exposure to any wastewater or to sludge samples. Algal growth was inhibited by raw or coagulated effluent to a similar extent and, again, the effluent from the biological treatment resulted in a decreased toxicity. The results suggest that coagulated effluent and conditioned sludge result in higher toxicity than raw influent in sea urchin embryos and sperm, whereas the biological wastewater treatment of coagulated effluent, in both sea urchins and algae, cause a substantial improvement of wastewater quality. Hence a final biological wastewater treatment should be operated to minimize any environmental damage from tannery wastewater.

Proposal for a screening test to evaluate the fate of organic micropollutants in activated sludge.

PubMed

Salvetti, Roberta; Vismara, Renato; Dal Ben, Ilaria; Gorla, Elena; Romele, Laura

2011-04-01

The concentrations of organic micropollutants are usually low in wastewaters (order of magnitude of mg L(-1)). However, their emission standards, especially in the case of carcinogenic and bioaccumulating substances, are often much lower (order of magnitude of microg L(-1)). Since these substances, in some cases, can be adsorbable or volatile, their removal via volatilization, biodegradation or sludge adsorption in a wastewater treatment plant (WWTP) becomes a significant feature to include in the usual design process, in order to verify the emission standards in gas and sludge too. In this study a simple screening batch test for the evaluation of the fate of organic micropollutants in water, air and sludge is presented. The test is set up by means of simple laboratory instruments and simulates an activated sludge tank process. In this study the results obtained for four substances with different chemical properties (i.e. toluene, benz(a)anthracene, phenol and benzene) are presented. The screening test proposed can be a useful tool to assess in about one month the fate of organic micropollutants in an activated sludge tank of a WWTP. Moreover, the test can constitute a useful support in the use of mathematical models, since it allows the verification of model results and the calibration of the reactions involved in the removal process.

Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge.

PubMed

Inoue, Daisuke; Suzuki, Yuta; Uchida, Takahiro; Morohoshi, Jota; Sei, Kazunari

2016-01-01

This study was conducted to evaluate the polyhydroxyalkanoate (PHA) production potential of cultivable heterotrophic bacteria in activated sludge by genotypic and phenotypic characterizations. A total of 114 bacterial strains were isolated from four activated sludge samples taken from a lab-scale sequencing batch reactor and three wastewater treatment processes of two municipal wastewater treatment plants. PCR detection of the phaC genes encoding class I and II PHA synthase revealed that 15% of the total isolates possessed phaC genes, all of which had the closest similarities to known phaC genes of α- and β-Proteobacteria and Actinobacteria. PHA production experiments under aerobic and nitrogen-limited conditions showed that 68% of the total isolates were capable of producing PHA from at least one of the six substrates used (acetate, propionate, lactate, butyrate, glucose and glycerol). Genotypic and phenotypic characterizations revealed that 75% of the activated sludge bacteria had PHA production potential. Our results also indicated that short-chain fatty acids would be the preferable substrates for PHA production by activated sludge bacteria, and that there might be a variety of unidentified phaC genes in activated sludge. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Sewage sludge drying by energy recovery from OFMSW composting: Preliminary feasibility evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rada, Elena Cristina; Ragazzi, Marco; Villotti, Stefano

2014-05-01

Highlights: • The aim is to support the drying of sewage sludge, using a solar greenhouse. • The system allows the exploitation of heat available from OFMSW aerobic process. • Another aim is to face the problem of OFMSW treatment, in particular food waste. • Energy and mass balances are presented for a case study. - Abstract: In this paper an original energy recovery method from composting is analyzed. The integrated system exploits the heat available from the aerobic biochemical process in order to support the drying of sewage sludge, using a specific solar greenhouse. The aim is to tacklemore » the problem of organic waste treatment, with specific regard to food waste. This is done by optimizing the energy consumption of the aerobic process of composting, using the heat produced to solve a second important waste management problem such as the sewage waste treatment. Energy and mass balances are presented in a preliminary feasibility study. Referring to a composting plant with a capacity of 15,000 t/y of food waste, the estimation of the power from recovered heat for the entire plant resulted about 42 kW. The results demonstrated that the energy recoverable can cover part of the heat necessary for the treatment of sludge generated by the population served by the composting plant (in terms of food waste and green waste collection). The addition of a renewable source such as solar energy could cover the residual energy demand. The approach is presented in detail in order for it to be replicated in other case studies or at full scale applications.« less

Sludge quantification at water treatment plant and its management scenario.

PubMed

Ahmad, Tarique; Ahmad, Kafeel; Alam, Mehtab

2017-08-15

Large volume of sludge is generated at the water treatment plants during the purification of surface water for potable supplies. Handling and disposal of sludge require careful attention from civic bodies, plant operators, and environmentalists. Quantification of the sludge produced at the treatment plants is important to develop suitable management strategies for its economical and environment friendly disposal. Present study deals with the quantification of sludge using empirical relation between turbidity, suspended solids, and coagulant dosing. Seasonal variation has significant effect on the raw water quality received at the water treatment plants so forth sludge generation also varies. Yearly production of the sludge in a water treatment plant at Ghaziabad, India, is estimated to be 29,700 ton. Sustainable disposal of such a quantity of sludge is a challenging task under stringent environmental legislation. Several beneficial reuses of sludge in civil engineering and constructional work have been identified globally such as raw material in manufacturing cement, bricks, and artificial aggregates, as cementitious material, and sand substitute in preparing concrete and mortar. About 54 to 60% sand, 24 to 28% silt, and 16% clay constitute the sludge generated at the water treatment plant under investigation. Characteristics of the sludge are found suitable for its potential utilization as locally available construction material for safe disposal. An overview of the sustainable management scenario involving beneficial reuses of the sludge has also been presented.

Planning Considerations. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Carnegie, John W.

This lesson deals with special considerations that should be made when choosing a sludge solids management program, briefly describing the source of solids in wastewater and why they must be dealt with. The various solids handling processes and ultimate disposal methods are also briefly described, followed by a detailed discussion of the technical…

Activated Sludge. Instructor's Guide. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Boe, Owen K.

This instructor's guide contains the materials needed to teach a seven-lesson unit on activated sludge. These materials include an overview of the unit, lesson plans, lecture outlines (keyed to slides designed for use with the lessons), student worksheets for each of the seven lessons (with answers), and two copies of a final quiz (with and…

Application of Sludges and Wastewaters on Agricultural Land: A Planning and Educational Guide, MCD-35. Research Bulletin 1090.

ERIC Educational Resources Information Center

Knezek, Bernard D., Ed.; Miller, Robert H., Ed.

This report addresses the application of agricultural processing wastes, industrial and municipal wastes on agricultural land as both a waste management and resource recovery and reuse practice. The document emphasizes the treatment and beneficial utilization of sludge and wastewater as opposed to waste disposal. These objectives are achieved…

Degradation of PPCPs in activated sludge from different WWTPs in Denmark.

PubMed

Chen, Xijuan; Vollertsen, Jes; Nielsen, Jeppe Lund; Dall, Agnieszka Gieraltowska; Bester, Kai

2015-12-01

Pharmaceuticals and Personal care products (PPCPs) are often found in effluents from wastewater treatment plants (WWTPs) due to insufficient removal during wastewater treatment processes. To understand the factors affecting the removal of PPCPs in classical activated sludge WWTPs, the present study was performed to assess the removal of frequently occurring pharmaceuticals (Naproxen, Fenoprofen, Ketoprofen, Dichlofenac, Carbamazepine) and the biocide Triclosan in activated sludge from four different Danish WWTPs. The respective degradation constants were compared to operational parameters previous shown to be of importance for degradation of micropollutants such as biomass concentration, and sludge retention time (SRT). The most rapid degradation, was observed for NSAID pharmaceuticals (55-90% for Fenoprofen, 77-94% for Ketoprofen and 46-90% for Naproxen), followed by Triclosan (61-91%), while Dichlofenac and Carbamazepine were found to be persistent in the systems. Degradation rate constants were calculated as 0.0026-0.0407 for NSAID pharmaceuticals and 0.0022-0.0065 for triclosan. No relationships were observed between degradation rates and biomass concentrations in the diverse sludges. However, for the investigated PPCPs, the optimal SRT was within 14-20 days (for these values degradation of these PPCPs was the most efficient). Though all of these parameters influence the degradation rate, none of them seems to be overall decisive. These observations indicate that the biological composition of the sludge is more important than the design parameters of the respective treatment plant.

Improving bioelectricity generation and COD removal of sewage sludge in microbial desalination cell.

PubMed

Ebrahimi, Atieh; Yousefi Kebria, Daryoush; Darzi, Ghasem Najafpour

2018-05-01

Improving wastewater treatment process and water desalination are two important solutions for increasing the available supply of fresh water. Microbial desalination cells (MDCs) with common electrolytes display relatively low organic matter removal and high cost. In this study, sewage sludge was used as the substrate in the Microbial desalination cell (MDC) under three different initial salt concentrations (5, 20 and 35 g.L -1 ) and the maximum salt removal rates of 50.6%, 64% and 69.6% were obtained under batch condition, respectively. The MDC also produced the maximum power density of 47.1 W m -3 and the averaged chemical oxygen demand (COD) removal of 58.2 ± 0.89% when the initial COD was 6610 ± 83 mg L -1 . Employing treated sludge as catholyte enhanced COD removal and power density to 87.3% and 54.4 W m -3 , respectively, with counterbalancing pH variation in treated effluent. These promising results showed, for the first time, that the excess sewage sludge obtained from biological wastewater treatment plants could be successfully used as anolyte and catholyte in MDC, achieving organic matter biodegradation along with salt removal and energy production. In addition, using treated sludge as catholyte will improve the performance of MDC and introduce a more effective method for both sludge treatment and desalination.

Inertization of heavy metals present in galvanic sludge by DC thermal plasma.

PubMed

Leal Vieira Cubas, Anelise; de Medeiros Machado, Marília; de Medeiros Machado, Marina; Gross, Frederico; Magnago, Rachel Faverzani; Moecke, Elisa Helena Siegel; Gonçalvez de Souza, Ivan

2014-01-01

Galvanic sludge results from the treatment of effluents generated by the industrial metal surface treatment of industrial material, which consists in the deposition of a metal on a surface or a metal surface attack, for example, electrodeposition of conductors (metals) and non conductive, phosphate, anodizing, oxidation and/or printed circuit. The treatment proposed here is exposure of the galvanic sludge to the high temperatures provided by thermal plasma, a process which aims to vitrify the galvanic sludge and render metals (iron, zinc, and chromium) inert. Two different plasma reactors were assembled: with a DC transferred arc plasma torch and with a DC nontransferred arc plasma torch. In this way it was possible to verify which reactor was more efficient in the inertization of the metals and also to investigate whether the addition of quartzite sand to the sludge influences the vitrification of the material. Quantification of water content and density of the galvanic raw sludge were performed, as well as analyzes of total organic carbon (TOC) and identify the elements that make up the raw sludge through spectroscopy X-ray fluorescence (XRF). The chemical composition and the form of the pyrolyzed and vitrified sludge were analyzed by scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM-EDS) analysis, which it is a analysis that shows the chemical of the sample surface. The inertization of the sludge was verified in leaching tests, where the leachate was analyzed by flame atomic absorption spectroscopy (FAAS). The results of water content and density were 64.35% and 2.994 g.cm(-3), respectively. The TOC analysis determined 1.73% of C in the sample of galvanic raw sludge, and XRF analysis determined the most stable elements in the sample, and showed the highest peaks (higher stability) were Fe, Zn, and Cr. The efficiency of the sludge inertization was 100% for chromium, 99% for zinc, and 100% for iron. The results also showed that the most efficient reactor was that with the DC transferred arc plasma torch and quartzite sand positively influenced by the vitrification during the pyrolysis of the galvanic sludge.

Evaluating sedimentation problems in activated sludge treatment plants operating at complete sludge retention time.

PubMed

Amanatidou, Elisavet; Samiotis, Georgios; Trikoilidou, Eleni; Pekridis, George; Taousanidis, Nikolaos

2015-02-01

Zero net sludge growth can be achieved by complete retention of solids in activated sludge wastewater treatment, especially in high strength and biodegradable wastewaters. When increasing the solids retention time, MLSS and MLVSS concentrations reach a plateau phase and observed growth yields values tend to zero (Yobs ≈ 0). In this work, in order to evaluate sedimentation problems arised due to high MLSS concentrations and complete sludge retention operational conditions, two identical innovative slaughterhouse wastewater treatment plants were studied. Measurements of wastewaters' quality characteristics, treatment plant's operational conditions, sludge microscopic analysis and state point analysis were conducted. Results have shown that low COD/Nitrogen ratios increase sludge bulking and flotation phenomena due to accidental denitrification in clarifiers. High return activated sludge rate is essential in complete retention systems as it reduces sludge condensation and hydraulic retention time in the clarifiers. Under certain operational conditions sludge loading rates can greatly exceed literature limit values. The presented methodology is a useful tool for estimation of sedimentation problems encountered in activated sludge wastewater treatment plants with complete retention time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biotreatment from hot bugs to cold ducks

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-02-01

There are few forms of industrial wastes that cannot be neutralized and disposed of using modern treatment methods. The challenge is to control costs and minimize liability. Such is the quandary for waste treatment facilities dealing with biological sludge. One way to reduce sludge volume is to use a high-temperature aerobic treatment process, such as the one recently commercialized by US Filter. The process relies on a strain of bacteria heated to 50--65 C. The high temperatures destroy pathogens and speed metabolism. Cultivated in a lagoon or pond treatment system, the duckweed floats on top of the water and feedsmore » on the organics. The plants consume nitrogen, ammonia and phosphoric compounds, help retain aerobic conditions in the pond, and control algae growth by blocking sunlight.« less

A pilot-scale microwave technology for sludge sanitization and drying.

PubMed

Mawioo, Peter M; Garcia, Hector A; Hooijmans, Christine M; Velkushanova, Konstantina; Simonič, Marjana; Mijatović, Ivan; Brdjanovic, Damir

2017-12-01

Large volumes of sludge are produced from onsite sanitation systems in densely populated areas (e.g. slums and emergency settlements) and wastewater treatment facilities that contain high amounts of pathogens. There is a need for technological options which can effectively treat the rapidly accumulating sludge under these conditions. This study explored a pilot-scale microwave (MW) based reactor as a possible alternative for rapid sludge treatment. The reactor performance was examined by conducting a series of batch tests using centrifuged waste activated sludge (C-WAS), non-centrifuged waste activated sludge (WAS), faecal sludge (FS), and septic tank sludge (SS). Four kilograms of each sludge type were subjected to MW treatment at a power of 3.4kW for various time durations ranging from 30 to 240min. During the treatment the temperature change, bacteria inactivation (E. coli, coliforms, Staphylococcus aureus, and enterococcus faecalis) and sludge weight/volume reduction were measured. Calorific values (CV) of the dried sludge and the nutrient content (total nitrogen (TN) and total phosphorus (TP)) in both the dried sludge and the condensate were also determined. It was found that MW treatment was successful to achieve a complete bacterial inactivation and a sludge weight/volume reduction above 60%. Besides, the dried sludge and condensate had high energy (≥16MJ/kg) and nutrient contents (solids; TN≥28mg/g TS and TP≥15mg/g TS; condensate TN≥49mg/L TS and TP≥0.2mg/L), having the potential to be used as biofuel, soil conditioner, fertilizer, etc. The MW reactor can be applied for the rapid treatment of sludge in areas such as slums and emergency settlements. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Effect of lime addition during sewage sludge treatment on characteristics of resulting SSA when it is used in cementitious materials.

PubMed

Vouk, D; Nakic, D; Štirmer, N; Baricevic, A

2017-02-01

Final disposal of sewage sludge is important not only in terms of satisfying the regulations, but the aspect of choosing the optimal wastewater treatment technology, including the sludge treatment. In most EU countries, significant amounts of stabilized and dewatered sludge are incinerated, and sewage sludge ash (SSA) is generated as a by product. At the same time, lime is one of the commonly used additives in the sewage sludge treatment primarily to stabilize the sludge. In doing so, the question arose how desirable is such addition of lime if the sludge is subsequently incinerated, and the generated ash is further used in the production of cementitious materials. A series of mortars were prepared where 10-20% of the cement fraction was replaced by SSA. Since all three types of analyzed SSA (without lime, with lime added during sludge stabilization and with extra lime added during sludge incineration) yielded nearly same results, it can be concluded that if sludge incineration is accepted solution, lime addition during sludge treatment is unnecessary even from the standpoint of preserving the pozzolanic properties of the resulting SSA. Results of the research carried out on cement mortars point to the great possibilities of using SSA in concrete industry.

Enhancing sewage sludge dewaterability by bioleaching approach with comparison to other physical and chemical conditioning methods.

PubMed

Liu, Fenwu; Zhou, Jun; Wang, Dianzhan; Zhou, Lixiang

2012-01-01

The sewage sludge conditioning process is critical to improve the sludge dewaterability prior to mechanical dewatering. Traditionally, sludge is conditioned by physical or chemical approaches, mostly with the addition of inorganic or organic chemicals. Here we report that bioleaching, an efficient and economical microbial method for the removal of sludge-borne heavy metals, also plays a significant role in enhancing sludge dewaterability. The effects of bioleaching and physical or chemical approaches on sludge dewaterability were compared. The conditioning result of bioleaching by Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans on sludge dewatering was investigated and compared with the effects of hydrothermal (121 degrees C for 2 hr), microwave (1050 W for 50 sec), ultrasonic (250 W for 2 min), and chemical conditioning (24% ferric chloride and 68% calcium oxide; dry basis). The results show that the specific resistance to filtration (SRF) or capillary suction time (CST) of sludge is decreased by 93.1% or 74.1%, respectively, after fresh sludge is conditioned by bioleaching, which is similar to chemical conditioning treatment with ferric chloride and calcium oxide but much more effective than other conditioning approaches including hydrothermal, microwave, and ultrasonic conditioning. Furthermore, after sludge dewatering, bioleached sludge filtrate contains the lowest concentrations of chroma (18 times), COD (542 mg/L), total N (TN, 300 mg/L), NH4(+)-N (208 mg/L), and total P (TP, 2 mg/L) while the hydrothermal process resulted in the highest concentration of chroma (660 times), COD (18,155 mg/L), TN (472 mg/L), NH4(+)-N (381 mg/L), and TP (191 mg/L) among these selected conditioning methods. Moreover, unlike chemical conditioning, sludge bioleaching does not result in a significant reduction of organic matter, TN, and TP in the resulting dewatered sludge cake. Therefore, considering sludge dewaterability and the chemical properties of sludge filtrate and resulting dewatered sludge cakes, bioleaching has potential as an approach for improving sludge dewaterability and reducing the cost of subsequent reutilization or disposal of dewatered sludge.

Effect of potassium ferrate on disintegration of waste activated sludge (WAS).

PubMed

Ye, Fenxia; Ji, Haizhuang; Ye, Yangfang

2012-06-15

The activated sludge process of wastewater treatment results in the generation of a considerable amount of excess activated sludge. Increased attention has been given to minimization of waste activated sludge recently. This paper investigated the effect of potassium ferrate oxidation pretreatment on the disintegration of the waste activated sludge at various dosages of potassium ferrate. The results show that potassium ferrate pretreatment disintegrated the sludge particle, resulting in the reduction of total solid content by 31%. The solubility (SCOD/TCOD) of the sludge increased with the increase of potassium ferrate dosage. Under 0.81 g/g SS dosage of potassium ferrate, SCOD/TCOD reached 0.32. Total nitrogen (TN) and total phosphorous (TP) concentrations in the solution all increased significantly after potassium ferrate pretreatment. The sludge particles reduced from 116 to 87 μm. The settleability of the sludge (SVI) was enhanced by 17%, which was due to the re-flocculation by the by-product, Fe(III), during potassium ferrate oxidation and the decrease of the viscosity. From the result of the present investigations, it can be concluded that potassium ferrate oxidation is a feasible method for disintegration of excess activated sludge. Copyright © 2012 Elsevier B.V. All rights reserved.

Study on improvement of sludge dewaterability with H2O2 cell lysis

NASA Astrophysics Data System (ADS)

Zhuo, Qiongfang; Yi, Hao; Zhang, Zhengke; Wang, Ji; Feng, Lishi; Xu, Zhencheng; Guo, Qingwei; Jin, Zhong; Lan, Yongzhe

2017-12-01

Excess sludge is the product of sewage treatment plants. With continuous perfection of municipal sewage treatment facilities in China, sludge output increases as a result of the growth of sewage treatment plants. Excess sludge has complicated compositions, including heavy metals, PPCPs, persistent organic pollutants. It owns high contents of organic matters and water. High-efficiency and low-cost dehydration of sludge is the key of sludge disposal. How to improve sludge dehydration efficiency is the research hotspot in the world. In this study, effects of hydrogen peroxide content and pH on sludge dehydration were discussed by chemical disintegration technique. The optimal hydrogen peroxide content and pH were discussed, aiming to search a high-efficiency sludge conditioner.

Process performance of high-solids batch anaerobic digestion of sewage sludge.

PubMed

Liao, Xiaocong; Li, Huan; Cheng, Yingchao; Chen, Nan; Li, Chenchen; Yang, Yuning

2014-01-01

The characteristics of high-solids anaerobic digestion (AD) of sewage sludge were investigated by comparison with conventional low-solids processes. A series of batch experiments were conducted under mesophilic condition and the initial solid contents were controlled at four levels of 1.79%, 4.47%, 10.28% and 15.67%. During these experiments, biogas production, organic degradation and intermediate products were monitored. The results verified that high-solids batch AD of sewage sludge was feasible. Compared with the low-solids AD with solid contents of 1.79% or 4.47%, the high-solids processes decreased the specific biogas yield per gram of sludge volatile solids slightly, achieved the same organic degradation rate of about 40% within extended degradation time, but increased the volumetric biogas production rate and the treatment capability of digesters significantly. The blocked mass and energy transfer, the low substrate to inoculum rate and the excessive cumulative free ammonia were the main factors impacting the performance of high-solids batch AD.

Sequential solar photo-fenton-biological system for the treatment of winery wastewaters.

PubMed

Mosteo, R; Sarasa, J; Ormad, Maria P; Ovelleiro, J L

2008-08-27

In this study, winery wastewaters are considered for degradation using heterogeneous photo-Fenton as a preliminary step before biotreatment. The heterogeneous photo-Fenton process assisted by solar light is able to partially degrade the organic matter present in winery wastewaters. When an initial hydrogen peroxide concentration of 0.1 M is used over 24 h of treatment, a degradation yield of organic matter (measured as TOC) of around 50% is reached. The later treatment (activated sludge process) allows the elimination of 90% of the initial TOC present in pretreated winery wastewaters without producing nondesired side-effects, such as the bulking phenomenon, which is usually detected when this treatment is used alone. The final effluent contains a concentration of organic matter (measured as COD) of 128 mg O2/L. The coupled system comprising the heterogeneous photo-Fenton process and biological treatment based on activated sludge in simple stage is a real alternative for the treatment of winery wastewater.

Effect of process parameters on greenhouse gas generation by wastewater treatment plants.

PubMed

Yerushalmi, L; Shahabadi, M Bani; Haghighat, F

2011-05-01

The effect of key process parameters on greenhouse gas (GHG) emission by wastewater treatment plants was evaluated, and the governing parameters that exhibited major effects on the overall on- and off-site GHG emissions were identified. This evaluation used aerobic, anaerobic, and hybrid anaerobic/aerobic treatment systems with food processing industry wastewater. The operating temperature of anaerobic sludge digester was identified to have the highest effect on GHG generation in the aerobic treatment system. The total GHG emissions of 2694 kg CO2e/d were increased by 72.5% with the increase of anaerobic sludge digester temperature from 20 to 40 degrees C. The operating temperature of the anaerobic reactor was the dominant controlling parameter in the anaerobic and hybrid treatment systems. Raising the anaerobic reactor's temperature from 25 to 40 degrees C increased the total GHG emissions from 5822 and 6617 kg CO2e/d by 105.6 and 96.5% in the anaerobic and hybrid treatment systems, respectively.

Vitrification as an alternative to landfilling of tannery sewage sludge.

PubMed

Celary, Piotr; Sobik-Szołtysek, Jolanta

2014-12-01

Due to high content of heavy metals such as chromium, tannery sewage sludge is a material which is difficult to be biologically treated as it is in the case of organic waste. Consequently, a common practice in managing tannery sewage sludge is landfilling. This poses a potential threat to both soil and water environments and it additionally generates costs of construction of landfills that meet specific environment protection requirements. Vitrification of this kind of sewage sludge with the addition of mineral wastes can represent an alternative to landfilling. The aim of this study was to investigate the possibility of obtaining an environmentally safe product by means of vitrification of tannery sewage sludge from a flotation wastewater treatment process and chemical precipitation in order to address the upcoming issue of dealing with sewage sludge from the tannery industry which will be prohibited to be landfilled in Poland after 2016. The focus was set on determining mixtures of tannery sewage sludge with additives which would result in the lowest possible heavy metal leaching levels and highest hardness rating of the products obtained from their vitrification. The plasma vitrification process was carried out for mixtures with various amounts of additives depending on the type of sewage sludge used. Only the materials of waste character were used as additives. One finding of the study was an optimum content of mineral additives in vitrified mixture of 30% v/v waste molding sands with 20% v/v carbonate flotation waste from the zinc and lead industry for the formulations with flotation sewage sludge, and 45% v/v and 5% v/v, respectively, for precipitation sewage sludge. These combinations allowed for obtaining products with negligible heavy metal leaching levels and hardness similar to commercial glass, which suggests they could be potentially used as construction aggregate substitutes. Incineration of sewage sludge before the vitrification process lead to increased hardness of the vitrificates and reduced leaching of some heavy metals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of EPA`s new methods to quantify vector attraction of wastewater sludges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrell, J.B.; Bhide, V.; Smith, J.E. Jr.

1996-05-01

EPA`s 1979 and 1993 sludge regulations require that sewage sludge be reduced in vector attraction before it can be applied to the land. In the 1979 regulation, satisfactory vector attraction reduction (VAR) could be demonstrated if treatment processes reduced the volatile solids content of sludge by 38%. The 1993 regulation adds two alternative test methods for aerobic sludges for determining whether VAR has been adequate. In the first method, specific oxygen uptake rate (SOUR) of the sludge must be <1.5 mg O{sub 2}/hr/g total solids, and in the second method, the additional volatile solids reduction (AVSR) that occurs when themore » sludge is further digested for 30 days must be <15%. Experimentation with the new tests is described. Comparisons among the three methods showed that the 38% VSR requirement and the SOUR test were equivalent only near 20{degree}C. The AVSR test was more conservative than either of the other tests. 18 refs., 7 figs., 3 tabs.« less

Integrated aerobic biological-chemical treatment of winery wastewater diluted with urban wastewater. LED-based photocatalysis in the presence of monoperoxysulfate.

PubMed

Solís, Rafael R; Rivas, Francisco Javier; Ferreira, Leonor C; Pirra, Antonio; Peres, José A

2018-01-28

The oxidation of Winery Wastewater (WW) by conventional aerobic biological treatment usually leads to inefficient results due to the presence of organic substances, which are recalcitrant or toxic in conventional procedures. This study explores the combination of biological and chemical processes in order to complete the oxidation of biodegradable and non-biodegradable compounds in two sequential steps. Thus, a biological oxidation of a diluted WW is carried out by using the activated sludge process. Activated sludge was gradually acclimated to the Diluted Winery Wastewater (DWW). Some aspects concerning the biological process were evaluated (kinetics of the oxidation and sedimentation of the sludge produced). The biological treatment of the DWW led to a 40-50% of Chemical Oxygen Demand (COD) removal in 8 h, being necessary the application of an additional process. Different chemical processes combining UVA-LEDs radiation, monoperoxysulfate (MPS) and photocatalysts were applied in order to complete the COD depletion and efficient removal of polyphenols content, poorly oxidized in the previous biological step. From the options tested, the combination of UVA, MPS and a novel LaCoO 3 -TiO 2 composite, with double route of MPS decomposition through heterogeneous catalysis and photocatalysis, led to the best results (95% of polyphenol degradation, and additional 60% of COD removal). Initial MPS concentration and pH effect in this process were assessed.

Agricultural recycling of treatment-plant sludge: a case study for a vegetable-processing factory.

PubMed

Dolgen, Deniz; Alpaslan, M Necdet; Delen, Nafiz

2007-08-01

The present study evaluated the possibility of using the sludge produced by a vegetable-processing factory in agriculture. The sludge was amended with a soil mixture (i.e., a mixture of sand, soil, and manure) and was applied at 0, 165, 330, 495 and 660 t/ha to promote the growth of cucumbers. The effects of various sludge loadings on plant growth were assessed by counting plants and leaves, measuring stem lengths, and weighing the green parts and roots of the plants. We also compared heavy metal uptake by the plants for sludge loadings of 330, 495, and 660 t/ha with various recommended standards for vegetables. Our results showed that plant growth patterns were influenced to some extent by the sludge loadings. In general, the number of leaves, stem length, and dry weight of green parts exhibited a pronounced positive growth response compared with an unfertilized control, and root growth showed a lesser but still significant response at sludge loadings of 165 and 330 t/ha. The sludge application caused no significant increase in heavy metal concentrations in the leaves, though zinc (Zn) and iron (Fe) were found at elevated concentrations. However, despite the Zn and Fe accumulation, we observed no toxicity symptoms in the plants. This may be a result of cucumber's tolerance of high metal levels.

The impact of temporal variability of excess sludge characteristics on the effects obtained in the process of its ultrasonic disintegration.

PubMed

Tytła, Malwina; Zielewicz, Ewa

2017-09-13

This paper aimed to indicate the characteristics of excess sludge, which have the greatest impact on the effects obtained during its ultrasonic disintegration (UD). The direct and technological effects observed after sludge disintegration and anaerobic digestion (AD) depend on the factors affecting the quality of its matrix and simply on the parameters of a disintegrator. Sludge samples originate from a Central Waste Water Treatment Plant in Gliwice, and were collected after mechanical thickening by a monthly period. This approach allowed to observe the temporal changes of sludge characteristics, in a continuous manner. To evaluate the achieved disintegration effects, the following indicators were used: degree of disintegration (DD COD ) and the author's indicators describing the direct and technological effects of UD (ID i , IT i , IT d ), based on the changes in the sludge characteristics. Disintegration was carried out by means of an ultrasonic device equipped with a thin sonotrode. AD was conducted under mesophilic conditions for 20 days. Statistical analysis confirmed that the most important parameters of sludge, which determine obtained effects, were total and volatile solids, capillary suction time, concentration of chemical oxygen demand and pH value. The investigations have also showed that the increase in sludge temperature during its disintegration has a significant impact on the magnitude of other effects obtained in the process.

[Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].

PubMed

Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang

2014-04-01

Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

Kinetics and reversibility of micropollutant sorption in sludge.

PubMed

Barret, Maialen; Carrère, Hélène; Patau, Mathieu; Patureau, Dominique

2011-10-01

The fate of micropollutants throughout wastewater treatment systems is highly dependent on their sorption interactions with sludge matter. In this study, both the sorption and desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) in activated sludge were shown to be very rapid in comparison to biodegradation kinetics. It was concluded that PAH transfer does not limit their biodegradation and that their fate is governed by the sorption/desorption equilibrium state. The effect of contact time between sludge and PAHs was also investigated. It was shown that aging did not influence the sorption/desorption equilibrium although PAH losses during aging suggest that sequestration phenomena had occurred. This implies that for PAH sorption assessment within treatment processes there is no need to include a contact time dimension. As a consequence, thanks to an innovative approach taking into account sorption equilibria and sequestration, this work has demonstrated that studies in the literature which, in main, deal with micropollutant sorption in sewage sludge with only a short contact time can be extrapolated to real systems in which sorption, desorption and aging occur.

A novel rotation generator of hydrodynamic cavitation for waste-activated sludge disintegration.

PubMed

Petkovšek, Martin; Mlakar, Matej; Levstek, Marjetka; Stražar, Marjeta; Širok, Brane; Dular, Matevž

2015-09-01

The disintegration of raw sludge is very important for enhancement of the biogas production in anaerobic digestion process as it provides easily degradable substrate for microorganisms to perform maximum sludge treatment efficiency and stable digestion of sludge at lower costs. In the present study the disintegration was studied by using a novel rotation generator of hydrodynamic cavitation (RGHC). At the first stage the analysis of hydrodynamics of the RGHC were made with tap water, where the cavitation extent and aggressiveness was evaluated. At the second stage RGHC was used as a tool for pretreatment of a waste-activated sludge (WAS), collected from wastewater treatment plant (WWTP). In case of WAS the disintegration rate was measured, where the soluble chemical oxygen demand (SCOD) and soluble Kjeldahl nitrogen were monitored and microbiological pictures were taken. The SCOD increased from initial 45 mg/L up to 602 mg/L and 12.7% more biogas has been produced by 20 passes through RGHC. The results were obtained on a pilot bioreactor plant, volume of 400 L. Copyright © 2015. Published by Elsevier B.V.

Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

PubMed

Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

2015-11-01

This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the application on the soil of sludge stabilized by liming or anaerobic digestion.

Integrated copper-containing wastewater treatment using xanthate process.

PubMed

Chang, Yi-Kuo; Chang, Juu-En; Lin, Tzong-Tzeng; Hsu, Yu-Ming

2002-09-02

Although, the xanthate process has been shown to be an effective method for heavy metal removal from contaminated water, a heavy metal contaminated residual sludge is produced by the treatment process and the metal-xanthate sludge must be handled in accordance with the Taiwan EPA's waste disposal requirements. This work employed potassium ethyl xanthate (KEX) to remove copper ions from wastewater. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) were used to determine the leaching potential and stability characteristics of the residual copper xanthate (Cu-EX) complexes. Results from metal removal experiments showed that KEX was suitable for the treatment of copper-containing wastewater over a wide copper concentration range (50, 100, 500, and 1000 mg/l) to the level that meets the Taiwan EPA's effluent regulations (3mg/l). The TCLP results of the residual Cu-EX complexes could meet the current regulations and thus the Cu-EX complexes could be treated as a non-hazardous material. Besides, the results of SDLT indicated that the complexes exhibited an excellent performance for stabilizing metals under acidic conditions, even slight chemical changes of the complexes occurred during extraction. The xanthate process, mixing KEX with copper-bearing solution to form Cu-EX precipitates, offered a comprehensive strategy for solving both copper-containing wastewater problems and subsequent sludge disposal requirements.

Partition and fate analysis of fluoroquinolones in sewage sludge during anaerobic digestion with thermal hydrolysis pretreatment.

PubMed

Li, Ning; Liu, Huajie; Xue, Yonggang; Wang, Hongyang; Dai, Xiaohu

2017-03-01

Fluoroquinolones (FQs) are broad-spectrum synthetic antibiotics that play an important role in the treatment of serious bacterial infections. FQs can reach wastewater treatment plants from different routes, and eventually accumulate in activated sludge. In this study, a solid-phase extraction (SPE) with HPLC-FLD detection method was utilized to investigate the partition and fate of FQs in digested sludge when thermal hydrolysis was used as pretreatment. As a result, thermal hydrolysis showed minor effects on the fate of FQs in batch anaerobic digestion processes, while anaerobic digestion alone removed >60% FQs and finally assisted in the mitigation of the inhibitory effects to microbial communities. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioleaching of heavy metals from sewage sludge: a review.

PubMed

Pathak, Ashish; Dastidar, M G; Sreekrishnan, T R

2009-06-01

During the treatment of sewage, a huge volume of sludge is generated, which is disposed of on land as soil fertilizer/conditioner due to the presence of nitrogen, phosphorus, potassium and other nutrients. However, the presence of toxic heavy metals and other toxic compounds in the sludge restricts its use as a fertilizer. Over the years, bioleaching has been developed as an environmentally friendly and cost-effective technology for the removal of heavy metals from the sludge. The present paper gives an overview of the various bioleaching studies carried out in different modes of operation. The various important aspects such as pathogen destruction, odor reduction and metal recovery from acidic leachate also have been discussed. Further, a detailed discussion was made on the various technical problems associated with the bioleaching process, which need to be addressed while developing the process on a larger scale.

Bioleaching of heavy metals from sewage sludge using Acidithiobacillus thiooxidans

NASA Astrophysics Data System (ADS)

Wen, Ye-Ming; Lin, Hong-Yan; Wang, Qing-Ping; Chen, Zu-Liang

2010-11-01

Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavy metals in sewage sludge did meet the requirement the standards of nation.

Species-dependence of cyanobacteria removal efficiency by different drinking water treatment processes.

PubMed

Zamyadi, Arash; Dorner, Sarah; Sauvé, Sébastien; Ellis, Donald; Bolduc, Anouka; Bastien, Christian; Prévost, Michèle

2013-05-15

Accumulation and breakthrough of several potentially toxic cyanobacterial species within drinking water treatment plants (DWTP) have been reported recently. The objectives of this project were to test the efficiency of different treatment barriers in cyanobacterial removal. Upon observation of cyanobacterial blooms, intensive sampling was conducted inside a full scale DWTP at raw water, clarification, filtration and oxidation processes. Samples were taken for microscopic speciation/enumeration and microcystins analysis. Total cyanobacteria cell numbers exceeded World Health Organisation and local alert levels in raw water (6,90,000 cells/mL). Extensive accumulation of cyanobacteria species in sludge beds and filters, and interruption of treatment were observed. Aphanizomenon cells were poorly coagulated and they were not trapped efficiently in the sludge. It was also demonstrated that Aphanizomenon cells passed through and were not retained over the filter. However, Microcystis, Anabaena, and Pseudanabaena cells were adequately removed by clarification and filtration processes. The breakthrough of non toxic cyanobacterial cells into DWTPs could also result in severe treatment disruption leading to plant shutdown. Application of intervention threshold values restricted to raw water does not take into consideration the major long term accumulation of potentially toxic cells in the sludge and the risk of toxins release. Thus, a sampling regime inside the plant adapted to cyanobacterial occurrence and intensity is recommended. Copyright © 2013 Elsevier Ltd. All rights reserved.

Environmental assessment of different dewatering and drying methods on the basis of life cycle assessment.

PubMed

Stefaniak, J; Zelazna, A; Pawłowski, A

2014-01-01

Sewage sludge is an inevitable product of wastewater treatment in municipal wastewater plants and its amount has increased dramatically due to the growing number of sewage systems users. This sludge needs to be adequately treated in order to decrease its hazardous properties and any negative influence on the environment. In this paper, gate to gate analysis, on the basis of life cycle assessment (LCA), was carried out in order to compare the environmental impact of alternative ways of sludge processing employing a dewatering press and three different kinds of dryers - belt dryer, container dryer and batch dryer. SimaPro 7.2 software and Ecoinvent 2.2 database were used to estimate the carbon footprint and energy balance of these processes. The main energy consumption in the scenarios analyzed is caused by the drying process. The solution based on application of the batch dryer allows a saving of 39.6% of energy compared with the most energy-consuming solution using a belt dryer. Sludge processing using belt and container dryers cause greater environmental burdens.

Co-pelletization of sewage sludge and agricultural wastes.

PubMed

Yilmaz, Ersel; Wzorek, Małgorzata; Akçay, Selin

2018-06-15

This paper concerns the process of production and properties of pellets based on biomass wastes. Co-pelletization was performed for sewage sludge from municipal wastewater treatment plant and other biomass material such as animal and olive wastes. The aim of the present study was to identify the key factors affecting on the sewage sludge and agricultural residues co-pelletization processes conditions. The impact of raw material type, pellet length, moisture content and particle size on the physical properties was investigated. The technic and technological aspects of co-pelletization were discussed in detail. The physical parameters of pellets, i.e.: drop strength, absorbability and water resistance were determined. Among others, also energy parameters: low and high heat value, content of ash and volatiles were presented. Results showed the range of raw materials moisture, which is necessary to obtain good quality biofuels and also ratio of sewage sludge in pelletizing materials. The analysis of the energetic properties has indicated that the pellet generated on the basis of the sewage sludge and another biomass materials can be applied in the processes of co-combustion with coal. Those biofuels are characterised with properties making them suitable for use in thermal processes and enabling their transport and storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-heating of dried industrial tannery wastewater sludge induced by pyrophoric iron sulfides formation.

PubMed

Bertani, R; Biasin, A; Canu, P; Della Zassa, M; Refosco, D; Simionato, F; Zerlottin, M

2016-03-15

Similarly to many powders of solids, dried sludge originated from tannery wastewater may result in a self-heating process, under given circumstances. In most cases, it causes a moderate heating (reaching 70-90°C), but larger, off-design residence times in the drier, in a suboxic atmosphere, extremely reactive solids can be produced. Tannery waste contains several chemicals that mostly end up in the wastewater treatment sludge. Unexpected and uncontrolled self heating could lead to a combustion and even to environmental problems. Elaborating on previous studies, with the addition of several analytical determinations, before and after the self-heating, we attempted to formulate a mechanism for the onset of heating. We demonstrated that the system Fe/S/O has been involved in the process. We proved that the formation of small quantities of pyrophoric iron sulfides is the key. They are converted to sulfated by reaction with water and oxygen with exothermic processes. The pyrite/pyrrhotite production depends on the sludge drying process. The oxidation of sulfides to oxides and sulfates through exothermic steps, reasonably catalyzed by metals in the sludge, occurs preferentially in a moist environment. The mechanism has been proved by reproducing in the laboratory prolonged heating under anoxic/suboxic atmosphere. Copyright © 2015 Elsevier B.V. All rights reserved.

Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

PubMed

Chen, Shen-Yi; Chou, Li-Chieh

2016-08-01

Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

PubMed

Grübel, Klaudiusz; Suschka, Jan

2015-05-01

The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9 days MAD + 15 days TAD. Similar results were obtained for volatile solids (VS) reduction after two-stage anaerobic digestion. The highest decrease of VS was obtained when the first stage, the mesophilic digestion which lasted 7 days, was followed by thermophilic digestion for 17 days.

Identification of the microbial community composition and structure of coal-mine wastewater treatment plants.

PubMed

Ma, Qiao; Qu, Yuan-Yuan; Zhang, Xu-Wang; Shen, Wen-Li; Liu, Zi-Yan; Wang, Jing-Wei; Zhang, Zhao-Jing; Zhou, Ji-Ti

2015-06-01

The wastewater from coal-mine industry varies greatly and is resistant to biodegradation for containing large quantities of inorganic and organic pollutants. Microorganisms in activated sludge are responsible for the pollutants' removal, whereas the microbial community composition and structure are far from understood. In the present study, the sludges from five coal-mine wastewater treatment plants were collected and the microbial communities were analyzed by Illumina high-throughput sequencing. The diversities of these sludges were lower than that of the municipal wastewater treatment systems. The most abundant phylum was Proteobacteria ranging from 63.64% to 96.10%, followed by Bacteroidetes (7.26%), Firmicutes (5.12%), Nitrospira (2.02%), Acidobacteria (1.31%), Actinobacteria (1.30%) and Planctomycetes (0.95%). At genus level, Thiobacillus and Comamonas were the two primary genera in all sludges, other major genera included Azoarcus, Thauera, Pseudomonas, Ohtaekwangia, Nitrosomonas and Nitrospira. Most of these core genera were closely related with aromatic hydrocarbon degradation and denitrification processes. Identification of the microbial communities in coal-mine wastewater treatment plants will be helpful for wastewater management and control. Copyright © 2015 Elsevier GmbH. All rights reserved.

Distribution, mass load and environmental impact of multiple-class pharmaceuticals in conventional and upgraded municipal wastewater treatment plants in East China.

PubMed

Yuan, Xiangjuan; Qiang, Zhimin; Ben, Weiwei; Zhu, Bing; Qu, Jiuhui

2015-03-01

The occurrence, fate and environmental impact of 30 pharmaceuticals including sulfonamides, fluoroquinolones, tetracyclines, macrolides, dihydrofolate reductase inhibitors, β-blockers, antiepileptics, lipid regulators, and stimulants were studied in two municipal wastewater treatment plants (WWTPs) located in Wuxi City, East China. A total of 23 pharmaceuticals were detected in wastewater samples, with a maximum concentration of 16.1 μg L(-1) (caffeine) in the influent and 615.5 ng L(-1) (azithromycin) in the effluent; 19 pharmaceuticals were detected in sludge samples at concentrations up to 12.13 mg kg(-1), with ofloxacin, azithromycin and norfloxacin being the predominant species. Mass balance analysis showed that biodegradation primarily accounted for the removal of sulfonamides, most of the macrolides, and other miscellaneous pharmaceuticals, while adsorption onto the sludge was the primary removal pathway for fluoroquinolones, tetracylines, and azithromycin during biological treatment. The total mass loads of target pharmaceuticals per capita in the two WWTPs were in the ranges of 2681.8-4333.3, 248.0-416.6 and 214.6-374.5 μg per day per inhabitant in the influent, effluent and dewatered sludge, respectively. The upgraded Plant A adopting the combined anaerobic/anoxic/oxic and moving bed biofilm process exhibited a much higher removal of target pharmaceuticals than the conventional Plant B adopting the C-Orbal oxidation ditch process. The concentration levels of sulfamethoxazole, ofloxacin, ciprofloxacin and clarithromycin in the effluent, ofloxacin in the sludge, and the mixture of all target pharmaceuticals in both effluent and sludge posed a high risk to algae in aquatic environments.

Removal of steroid estrogens from municipal wastewater in a pilot scale expanded granular sludge blanket reactor and anaerobic membrane bioreactor

PubMed Central

Ito, Ayumi; Mensah, Lawson; Cartmell, Elise; Lester, John N.

2016-01-01

Anaerobic treatment of municipal wastewater offers the prospect of a new paradigm by reducing aeration costs and minimizing sludge production. It has been successfully applied in warm climates, but does not always achieve the desired outcomes in temperate climates at the biochemical oxygen demand (BOD) values of municipal crude wastewater. Recently the concept of ‘fortification' has been proposed to increase organic strength and has been demonstrated at the laboratory and pilot scale treating municipal wastewater at temperatures of 10–17°C. The process treats a proportion of the flow anaerobically by combining it with primary sludge from the residual flow and then polishing it to a high effluent standard aerobically. Energy consumption is reduced as is sludge production. However, no new treatment process is viable if it only addresses the problems of traditional pollutants (suspended solids – SS, BOD, nitrogen – N and phosphorus – P); it must also treat hazardous substances. This study compared three potential municipal anaerobic treatment regimes, crude wastewater in an expanded granular sludge blanket (EGSB) reactor, fortified crude wastewater in an EGSB and crude wastewater in an anaerobic membrane bioreactor. The benefits of fortification were demonstrated for the removal of SS, BOD, N and P. These three systems were further challenged with the removal of steroid estrogens at environmental concentrations from natural indigenous sources. All three systems removed these compounds to a significant degree, confirming that estrogen removal is not restricted to highly aerobic autotrophs, or aerobic heterotrophs, but is also a faculty of anaerobic bacteria. PMID:26212345

Behavior of pharmaceuticals in waste water treatment plant in Japan.

PubMed

Matsuo, H; Sakamoto, H; Arizono, K; Shinohara, R

2011-07-01

The fate of pharmaceuticals in a wastewater treatment plant (WWTP) in Kumamoto, Japan with activated sludge treatment is reported. Selected pharmaceuticals were detected in influent. Results from the present study confirmed that Acetaminophen, Amoxicillin, Ampicillin and Famotidine were removed at a high rate (>90% efficiency). In contrast, removal efficiency of Ketoprofen, Losartan, Oseltamivir, Carbamazepine, and Diclofenac was relatively low (<50%). The selected pharmaceuticals were also detected in raw sludge. In digestive process, Indomethacin, Atenolol, Famotidine, Trimethoprim and Cyclofosamide were removed at a high (>70% efficiency). On the other hand, removal of Carbamazepine, Ketoprofen and Diclofenac was not efficient (<50%).

A Guide to the Selection of Cost-Effective Wastewater Treatment Systems. Technical Report.

ERIC Educational Resources Information Center

Van Note, Robert H.; And Others

The data within this publication provide guidelines for planners, engineers and decision-makers at all governmental levels to evaluate cost-effectiveness of alternative wastewater treatment proposals. The processes described include conventional and advanced treatment units as well as most sludge handling and processing units. Flow sheets, cost…

Seasonal and spatial variations of PPCP occurrence, removal and mass loading in three wastewater treatment plants located in different urbanization areas in Xiamen, China.

PubMed

Sun, Qian; Li, Mingyue; Ma, Cong; Chen, Xiangqiang; Xie, Xiaoqing; Yu, Chang-Ping

2016-01-01

The occurrence and fate of 48 pharmaceuticals and personal care products (PPCPs) in three wastewater treatment plants (WWTPs) located in different urbanization areas in Xiamen, China was investigated over one year. Results showed that PPCPs were widely detected, but the major PPCPs in the influent, effluent, and sludge were different. Spatial and seasonal variations of PPCP levels in the influent and sludge were observed. The removal efficiencies for most PPCPs were similar among the three WWTPs, although they employed different biological treatment processes. Furthermore, the mass loadings per inhabitant of most pharmaceuticals had a positive correlation with the urbanization levels, indicating that most pharmaceutical usage was higher in the urban core compared to the suburban zones. The total mass loadings of all the 48 PPCPs in the effluent and waste sludge showed close proportions, which suggested the importance of proper waste sludge disposal to prevent a large quantity of PPCPs from entering the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Semi-aerobic fermentation as a novel pre-treatment to obtain VFA and increase methane yield from primary sludge.

PubMed

Peces, M; Astals, S; Clarke, W P; Jensen, P D

2016-01-01

There is a growing trend to consider organic wastes as potential sources of renewable energy and value-add products. Fermentation products have emerged as attractive value-add option due to relative easy production and broad application range. However, pre-fermentation and extraction of soluble products may impact down-stream treatment processes, particularly energy recovery by anaerobic digestion. This paper investigates primary sludge pre-fermentation at different temperatures (20, 37, 55, and 70°C), treatment times (12, 24, 48, and 72h), and oxygen availability (semi-aerobic, anaerobic); and its impact on anaerobic digestion. Pre-fermentation at 20 and 37°C succeeded for VFA production with acetate and propionate being major products. Pre-fermentation at 37, 55, and 70°C resulted in higher solubilisation yield but it reduced sludge methane potential by 20%. Under semi-aerobic conditions, pre-fermentation allowed both VFA recovery (43gCODVFAkg(-1)VS) and improved methane potential. The latter phenomenon was linked to fungi that colonised the sludge top layer during pre-fermentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of soluble and particulate substrate on the carbon and energy footprint of wastewater treatment processes.

PubMed

Gori, Riccardo; Jiang, Lu-Man; Sobhani, Reza; Rosso, Diego

2011-11-15

Most wastewater treatment plants monitor routinely carbonaceous and nitrogenous load parameters in influent and effluent streams, and often in the intermediate steps. COD fractionation discriminates the selective removal of VSS components in different operations, allowing accurate quantification of the energy requirements and mass flows for secondary treatment, sludge digestion, and sedimentation. We analysed the different effects of COD fractions on carbon and energy footprint in a wastewater treatment plant with activated sludge in nutrient removal mode and anaerobic digestion of the sludge with biogas energy recovery. After presenting a simple rational procedure for COD and solids fractions quantification, we use our carbon and energy footprint models to quantify the effects of varying fractions on carbon equivalent flows, process energy demand and recovery. A full-scale real process was modelled with this procedure and the results are reported in terms of energy and carbon footprint. For a given process, the increase of the ratio sCOD/COD increases the energy demand on the aeration reactors, the associated CO(2) direct emission from respiration, and the indirect emission for power generation. Even though it appears as if enhanced primary sedimentation is a carbon and energy footprint mitigation practice, care must be used since the nutrient removal process downstream may suffer from an excessive bCOD removal and an increased mean cell retention time for nutrient removal may be required. Copyright © 2011 Elsevier Ltd. All rights reserved.

Treatment of sugar processing industry effluent up to remittance limits: Suitability of hybrid electrode for electrochemical reactor.

PubMed

Sahu, Omprakash

2017-01-01

Sugar industry is an oldest accommodates industry in the world. It required and discharges a large amount of water for processing. Removal of chemical oxygen demand and color through the electrochemical process including hybrid iron and aluminum electrode was examined for the treatment of cane-based sugar industry wastewater. Most favorable condition at pH 6.5, inter-electrode gap 20 mm, current density 156 A m -2 , electrolyte concentration 0.5 M and reaction time 120 min, 90% COD and 93.5% color removal was achieved. The sludge generated after treatment has less organic contain, which can be used as manure in agricultural crops. Overall the electrocoagulation was found to be reliable, efficient and economically fit to treat the sugar industry wastewater. •Electrocoagulation method for sugar processing industry wastewater treatment Optimization of operating parameters for maximum efficiency.•Physicochemical analysis of sludge and scum.•Significance of hydride metal electrode for pollutant removal.

Reduction in excess sludge production in a dairy wastewater treatment plant via nozzle-cavitation treatment: case study of an on-farm wastewater treatment plant.

PubMed

Hirooka, Kayako; Asano, Ryoki; Yokoyama, Atsushi; Okazaki, Masao; Sakamoto, Akira; Nakai, Yutaka

2009-06-01

Nozzle-cavitation treatment was used to reduce excess sludge production in a dairy wastewater treatment plant. During the 450-d pilot-scale membrane bioreactor (MBR) operation, when 300 l of the sludge mixed liquor (1/10 of the MBR volume) was disintegrated per day by the nozzle-cavitation treatment with the addition of sodium hydrate (final concentration: 0.01% W/W) and returned to the MBR, the amount of excess sludge produced was reduced by 80% compared with that when sludge was not disintegrated. On the basis of the efficiency of CODCr removal and the ammonia oxidation reaction, it was concluded that the nozzle-cavitation treatment did not have a negative impact on the performance of the MBR. The estimation of the inorganic material balance showed that when the mass of the excess sludge was decreased, the inorganic content of the activated sludge increased and some part of the inorganic material was simultaneously solubilized in the effluent.

Simulation and optimization of a coking wastewater biological treatment process by activated sludge models (ASM).

PubMed

Wu, Xiaohui; Yang, Yang; Wu, Gaoming; Mao, Juan; Zhou, Tao

2016-01-01

Applications of activated sludge models (ASM) in simulating industrial biological wastewater treatment plants (WWTPs) are still difficult due to refractory and complex components in influents as well as diversity in activated sludges. In this study, an ASM3 modeling study was conducted to simulate and optimize a practical coking wastewater treatment plant (CWTP). First, respirometric characterizations of the coking wastewater and CWTP biomasses were conducted to determine the specific kinetic and stoichiometric model parameters for the consecutive aeration-anoxic-aeration (O-A/O) biological process. All ASM3 parameters have been further estimated and calibrated, through cross validation by the model dynamic simulation procedure. Consequently, an ASM3 model was successfully established to accurately simulate the CWTP performances in removing COD and NH4-N. An optimized CWTP operation condition could be proposed reducing the operation cost from 6.2 to 5.5 €/m(3) wastewater. This study is expected to provide a useful reference for mathematic simulations of practical industrial WWTPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synergistic effect of rice husk addition on hydrothermal treatment of sewage sludge: fate and environmental risk of heavy metals.

PubMed

Shi, Wansheng; Liu, Chunguang; Shu, Youju; Feng, Chuanping; Lei, Zhongfang; Zhang, Zhenya

2013-12-01

Hydrothermal treatment (HTT) at 200°C was applied to immobilize heavy metals (HMs) and the effect of rice husk (RH) addition was investigated based on total HMs concentration, fractionation and leaching tests. The results indicated that a synergistic effect of RH addition and HTT could be achieved on reducing the risk of HMs from medium and low risk to no risk. Metals were redistributed and transformed from weakly bounded state to stable state during the HTT process under RH addition. Notably at a RH/sludge ratio of 1/1.75 (d.w.), all the HMs showed no eco-toxicity and no leaching toxicity, with the concentrations of leachable Cr, Ni, Cu and Cd decreased by 17%, 89%, 95% and 93%, respectively. This synergistic effect of RH addition and HTT on the risk reduction of HMs implies that HTT process with RH addition could be a promising and safe disposal technology for sewage sludge treatment in practice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Supercritical water oxidation treatment of textile sludge.

PubMed

Zhang, Jie; Wang, Shuzhong; Li, Yanhui; Lu, Jinling; Chen, Senlin; Luo, XingQi

2017-08-01

In this work, we studied the supercritical water oxidation (SCWO) of the textile sludge, the hydrothermal conversion of typical textile compounds and the corrosion properties of stainless steel 316. Moreover, the influence mechanisms of NaOH during these related processes were explored. The results show that decomposition efficiency for organic matter in liquid phase of the textile sludge was improved with the increment of reaction temperature or oxidation coefficient. However, the organic substance in solid phase can be oxidized completely in supercritical water. Serious coking occurred during the high pressure water at 250-450°C for the Reactive Orange 7, while at 300 and 350°C for the polyvinyl alcohol. The addition of NaOH not only accelerated the destruction of organic contaminants in the SCWO reactor, but effectively inhibited the dehydration conversion of textile compounds during the preheating process, which was favorable for the treatment system of textile sludge. The corrosion experiment results indicate that the stainless steel 316 could be competent for the body materials of the reactor and the heat exchangers. Furthermore, there was prominent enhancement of sodium hydroxide for the corrosion resistance of 316 in subcritical water. On the contrary the effect was almost none during SCWO.

Greenhouse gases emissions accounting for typical sewage sludge digestion with energy utilization and residue land application in China.

PubMed

Niu, Dong-jie; Huang, Hui; Dai, Xiao-hu; Zhao, You-cai

2013-01-01

About 20 million tonnes of sludge (with 80% moisture content) is discharged by the sewage treatment plants per year in China, which, if not treated properly, can be a significant source of greenhouse gases (GHGs) emissions. Anaerobic digestion is a conventional sewage sludge treatment method and will continue to be one of the main technologies in the following years. This research has taken into consideration GHGs emissions from typical processes of sludge thickening+anaerobic digestion+dewatering+residue land application in China. Fossil CO(2), biogenic CO(2), CH(4,) and avoided CO(2) as the main objects is discussed respectively. The results show that the total CO(2)-eq is about 1133 kg/t DM (including the biogenic CO(2)), while the net CO(2)-eq is about 372 kg/t DM (excluding the biogenic CO(2)). An anaerobic digestion unit as the main GHGs emission source occupies more than 91% CO(2)-eq of the whole process. The use of biogas is important for achieving carbon dioxide emission reductions, which could reach about 24% of the total CO(2)-eq reduction. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of extracellular polymeric substances (EPS) treated by combined ultrasound pretreatment and chemical re-flocculation on water treatment sludge settling performance.

PubMed

Chen, Wei; Gao, Xiaohong; Xu, Hang; Cai, Yan; Cui, Jianfeng

2017-03-01

Extracellular polymeric substances (EPS) are high molecular weight polymers and play a significant role in floc stability, floc size, bioflocculation and sludge settleability. The destruction and reconstruction of EPS improve the performance of solid-water separation processes. In this study, the influence of combined ultrasound pretreatment and chemical re-flocculation on the spatial distribution and composition of EPS was examined. Settleability efficiency demonstrated that the optimal operating condition was an ultrasound pretreatment time of 15 min at pH 6. Sludge particles were greatly disintegrated and the protein-like substances were converted into smaller molecules after ultrasound treatment, and pH had important effects on solubilization and degradation of protein-like substances. The flocs of sludge water after addition of polyacrylamide were larger in size and denser in structure than those resulting from addition of polyaluminium chloride. However, polyaluminium chloride had a better capacity for degrading EPS, especially at a dosage of 1.2 g/g total suspended solids. The results of this research show that the combination of ultrasonication and chemical re-flocculation is effective in treating sludge water from a drinking water treatment plant. Copyright © 2016 Elsevier Ltd. All rights reserved.