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1

Membrane controlled anaerobic digestion  

NASA Astrophysics Data System (ADS)

In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

Omstead, D. R.

2

Fuel cell operation on anaerobic digester gas: conceptual design and assessment  

Microsoft Academic Search

The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at wastewater treatment plants during the process of treating sewage anaerobically to reduce solids. The economic feasibility study shows the fuel cell is economical where plant electricity costs are 5 ¢\\/kW

R. J. Spiegel; S. A. Thorneloe; J. C. Trocciola; J. L. Preston

1999-01-01

3

Enhancement of methane gas production using an industrial waste in anaerobic digestion  

SciTech Connect

One method of recycling that may aid in the solution of the current energy problems is anaerobic digestion. Chromium shavings are a solid waste produced by the leather tanning industry. Chromium can block enzymatic systems or interfere with essential cellular metabolites of most oxidizing bacteria. In general, heavy metals coagulate and precipitate proteins, many of which are denatured by this action. This study examines the effects on anaerobic digestion of chromium shavings from leather tanning. Leather chrome shavings contain proteins, nitrogen, and fats. These shavings were added to two of three digesters at various rates. The methane gas production of the experimental units improved significantly compared to the control. In addition, the presence of a toxic loading or change of feed had no harmful effect on the digester performance.

Fradkin, L.; Kremer, F.

1980-12-01

4

Enhancement of methane gas production using an industrial waste in anaerobic digestion  

SciTech Connect

One method of recycling that may aid in the solution of the current energy problems is anaerobic digestion. Chromium shavings are a solid waste produced by the leather tanning industry. Chromium can block enzymatic systems or interfere with essential cellular metabolites of most oxidizing bacteria. In general, heavy metals coagulate and precipitate proteins, many of which are denatured by this action. This study examines the effects on anaerobic digestion of chromium shavings from leather tanning. Leather chrome shavings contain proteins, nitrogen, and fats. These shavings were added to two of three digesters at various rates. The methane gas production of the experimental units improved significantly compared to the control. In addition, the presence of a toxic loading or change of feed had no harmful effect on the digester performance.

Fradkin, L.; Kremer, F.

1980-01-01

5

Celanese improves anaerobic digester  

Microsoft Academic Search

An anaerobic digestion process, developed by Celanese for the disposal of petrochemical wastes, involves feeding some of the treated effluent back into the system to dilute toxic constituents and to lower the pH. Anaerobic digestion as a disposal technique has been a problem since toxic materials and high pH kill the bacteria needed for effective operation. Operation of the process

E. R. Witt; T. E. Roberts

1979-01-01

6

First European fuel cell installation with anaerobic digester gas in a molten carbonate fuel cell  

Microsoft Academic Search

The City of Ahlen in North Rhine Westphalia, Germany and RWE Fuel Cells GmbH, Essen, cooperate in order to install a molten carbonate fuel cell in the municipal sewage works of Ahlen in May\\/June 2005. The MCFC unit, a so-called HotModule made by MTU CFC Solutions, Ottobrunn operates on anaerobic digester gas and provides power and heat for the sewage

M. Krumbeck; T. Klinge; B. Döding

2006-01-01

7

Fuel cell operation on anaerobic digester gas: Conceptual design and assessment  

SciTech Connect

The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at wastewater treatment plants during the process of treating sewage anaerobically to reduce solids. The economic feasibility study shows the fuel cell is economical where plant electricity costs are 5 [cents]/kW h or higher, based on entry level fuel cell costs of $3,000/kW. FCs are one of the cleanest energy technologies available, and the widespread use of this concept should result in a significant reduction in global warming gas and acid rain air emissions. Additionally, technology evaluation focused on improving a commercial phosphoric acid FC power plant operation on ADG is described.

Spiegel, R.J.; Thorneloe, S.A. (Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Lab.); Trocciola, J.C.; Preston, J.L. (ONSI Corp., South Windsor, CT (United States))

1999-01-01

8

Bibliography on anaerobic digestion  

SciTech Connect

The priority assigned to biogas systems by participants in A.I.D's Energy for Rural Development Program spurred the compilation of this 373-item bibliography on anaerobic digestion. The materials focus on energy technologies that are especially suited to the social, economic, and institutional concerns of rural Asia and the Pacific. Entries are presented in two sections. The first presents largely non-technical reports on anaerobic digesters in South and Southeast Asia, for the years 1956-80, with emphasis on the period 1970-80. The second section, which includes both technical and non-technical references, is a condensation of a computerized search of the U.S. Department of Energy's Energy Research Abstracts published during the period 1977-80. The search revealed a lack of reliable data, pointing to the need for further research on the technology and potential of anaerobic digestion.

Ramakrishna, J.; Pruett, D.M.; Santerre, M.T.; Toyoshiba, T.S.

1980-09-01

9

Anaerobic Digestion and Biocatalysis.  

National Technical Information Service (NTIS)

A report is given on the scope of the technical programmes in the UK and the US on anaerobic digestion and biocatalysis. The study arises from the Collaboration Agreement signed by the respective Secretaries of State for Energy in the UK and US in 1984. T...

1985-01-01

10

Anaerobic digestion process  

Microsoft Academic Search

First, the organic waste slurry of sewage sludge and\\/or kitchen garbage is stored in a stable condition after effecting partially thereto a liquefaction treatment in advance by adding liquefying bacteria, and next this slurry is effectively digested anaerobically by way of a liquefaction\\/gasification-mixed step or a liquefaction\\/gasification separated step.

M. Ishida; R. Haga; Y. Odawara

1984-01-01

11

Greenhouse gas emission reductions from domestic anaerobic digesters linked with sustainable sanitation in rural China.  

PubMed

Anaerobic digesters provide clean, renewable energy (biogas) by converting organic waste to methane, and are a key part of China's comprehensive rural energy plan. Here, experimental and modeling results are used to quantify the net greenhouse gas (GHG) reduction from substituting a household anaerobic digester for traditional energy sources in Sichuan, China. Tunable diode laser absorption spectroscopy and radial plume mapping were used to estimate the mass flux of fugitive methane emissions from active digesters. Using household energy budgets, the net improvement in GHG emissions associated with biogas installation was estimated using global warming commitment (GWC) as a consolidated measure of the warming effects of GHG emissions from cooking. In all scenarios biogas households had lower GWC than nonbiogas households, by as much as 54%. Even biogas households with methane leakage exhibited lower GWC than nonbiogas households, by as much as 48%. Based only on the averted GHG emissions over 10 years, the monetary value of a biogas installation was conservatively estimated at US$28.30 ($16.07 ton(-1) CO(2)-eq), which is available to partly offset construction costs. The interaction of biogas installation programs with policies supporting improved stoves, renewable harvesting of biomass, and energy interventions with substantial health cobenefits are discussed. PMID:21348471

Dhingra, Radhika; Christensen, Erick R; Liu, Yang; Zhong, Bo; Wu, Chang-Fu; Yost, Michael G; Remais, Justin V

2011-02-24

12

Greenhouse gas emission reductions from domestic anaerobic digesters linked with sustainable sanitation in rural China  

PubMed Central

Anaerobic digesters provide clean, renewable energy (biogas) by converting organic waste to methane, and are a key part of China's comprehensive rural energy plan. Here, experimental and modeling results are used to quantify the net greenhouse gas (GHG) reduction from substituting a household anaerobic digester for traditional energy sources in Sichuan, China. Tunable diode laser absorption spectroscopy and radial plume mapping were used to estimate the mass flux of fugitive methane emissions from active digesters. Using household energy budgets, the net improvement in GHG emissions associated with biogas installation was estimated using global warming commitment (GWC) as a consolidated measure of the warming effects of GHG emissions from cooking. In all scenarios biogas households had lower GWC than non-biogas households, by as much as 54%. Even biogas households with methane leakage exhibited lower GWC than non-biogas households, by as much as 48%. Based only on the averted GHG emissions over 10 years, the monetary value of a biogas installation was conservatively estimated at US$28.30 ($16.07 ton?1 CO2-eq.), which is available to partly offset construction costs. The interaction of biogas installation programs with policies supporting improved stoves, renewable harvesting of biomass, and energy interventions with substantial health co-benefits, are discussed.

DHINGRA, RADHIKA; CHRISTENSEN, ERICK R.; LIU, YANG; ZHONG, BO; WU, CHANG-FU; YOST, MICHAEL G.; REMAIS, JUSTIN V.

2013-01-01

13

Characterization of gas produced by the anaerobic digestion of municipal solid waste  

SciTech Connect

A large-scale proof-of-concept facility has been constructed in Pompano, Florida, to evaluate the feasibility of producing methane-rich gas from the anaerobic digestion of municipal solid waste. The University of Miami together with the AMES Research Laboratory are participating in the environmental source assessment of that technology. The ultimate goal is to determine if the products are environmentally acceptable or are of less environmental consequence (with or without controls) than if generated in an unprocessed landfill. This paper describes the gas analysis procedure and the gas composition as determined to date for unstable, lower mesophilic (30/sup 0/-40/sup 0/C) digester conditions and with the plant operating at only 15% of its design capacity. It is observed that the composition of the biogas from the large-scale facility is quite similar, with the possible exception of H/sub 2/S and NH/sub 3/, to that produced by small-scale digesters and in landfills. The CH/sub 4/ and CO/sub 2/ levels varied significantly about mean values of 55% and 45% respectively. At this stage of the evaluation, it appears that the potential environmental concern might be from the odorous components of the biogas.

Gerrish, H.P.; Daly, E.L.; Lascarro, J.F.; Nemerow, N.; Sengupta, S.; Wong, K.F.

1980-12-01

14

Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils.  

PubMed

Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH4Cl) was included as a reference treatment for mineral N. After 48days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application, indicating greater microbial activity in amended soil and reflecting the lower stability of this OM source, compared to the other, anaerobic digestate types, which showed no consistent effects on MBN compared to the control. Thus, the overall net release of digestate N in different soil types was not regulated by N transfer into the soil microbial biomass, but was determined primarily by digestate properties and the capacity of the soil type to process and turnover digestate N. In contrast to the sandy soil types, where nitrate (NO3(-)) concentrations increased during incubation, there was an absence of NO3(-) accumulation in the silty clay soil amended with LTAD and DMADMSW. This provided indirect evidence for denitrification activity and the gaseous loss of N, and the associated increased risk of greenhouse gas emissions under certain conditions of labile C supply and/or digestate physical structure in fine-textured soil types. The significance and influence of the interaction between soil type and digestate stability and physical properties on denitrification processes in digestate-amended soils require urgent investigation to ensure management practices are appropriate to minimise greenhouse gas emissions from land applied biowastes. PMID:24035244

Rigby, H; Smith, S R

2013-09-10

15

Anaerobic Digestion of Agricultural Solid Residues  

Microsoft Academic Search

Agricultural residues can be converted to methane-rich gas mixture. Anaerobic biomethane production is an effective process for conversion of a broad variety of agricultural residues to methane to substitute natural gas and medium calorific value gases. Methane generating bacteria (methanogens) and other microbes that help digest dying plants in anaerobic conditions. Agricultural solid residues (ASR) represent a potential energy resource

Ayhan Demirbas; Temel Ozturk

2005-01-01

16

Anaerobic Digestion of Cellulosic Wastes: Laboratory Tests.  

National Technical Information Service (NTIS)

Anaerobic digestion is a potentially attractive technology for volume reduction of cellulosic wastes. A substantial fraction of the waste is converted to off-gas and a relatively small volume of biologically stabilized sludge is produced. Process developm...

D. D. Lee T. L. Donaldson

1984-01-01

17

Hemicellulose conversion by anaerobic digestion  

Microsoft Academic Search

The digestibility of an aquatic biomass (water hyacinth), a land-based biomass (Coastal Bermuda grass), and a biomass-waste blend (a mixture of hyacinth, grass, MSW, and sludge) under various digestion conditions was studied. Anaerobic digestion of hemicellulose consists of the steps of enzymatic hydrolysis of hemicellulose to glucans, mannans, galactans, xylans, and arabans, and then to simple hexose and pentose sugars;

S. Ghosh; M. P. Henry; R. W. Christopher

1982-01-01

18

Anaerobic digestion of agricultural and other substrates--implications for greenhouse gas emissions.  

PubMed

The greenhouse gas (GHG) emissions, expressed in carbon dioxide equivalents (CO2-eq), of different Austrian biogas systems were analyzed and evaluated using life-cycle assessment (LCA) as part of a national project. Six commercial biogas plants were investigated and the analysis included the complete process chain: viz., the production and collection of substrates, the fermentation of the substrates in the biogas plant, the upgrading of biogas to biomethane (if applicable) and the use of the biogas or biomethane for heat and electricity or as transportation fuel. Furthermore, the LCA included the GHG emissions of construction, operation and dismantling of the major components involved in the process chain, as well as the use of by-products (e.g. fermentation residues used as fertilizers). All of the biogas systems reduced GHG emissions (in CO2-eq) compared with fossil reference systems. The potential for GHG reduction of the individual biogas systems varied between 60% and 100%. Type of feedstock and its reference use, agricultural practices, coverage of storage tanks for fermentation residues, methane leakage at the combined heat and power plant unit and the proportion of energy used as heat were identified as key factors influencing the GHG emissions of anaerobic digestion processes. PMID:23739470

Pucker, J; Jungmeier, G; Siegl, S; Pötsch, E M

2013-06-01

19

Anaerobic digestion of cellulosic wastes  

SciTech Connect

Anaerobic digestion is a potentially attractive technology for volume reduction of low-level radioactive cellulosic wastes. A substantial fraction of the waste is converted to off-gas and a relatively small volume of biologically stabilized sludge is produced. Process development work has been completed using a 75-L digester to verify rates and conversions obtained at the bench scale. Start-up and operating procedures have been developed, and effluent was generated for characterization and disposal studies. Three runs using batch and fed-batch conditions were made lasting 36, 90, and 423 d. Solids solubilization rates and gas production rates averaged approximately 1.8 g cellulose per L of reactor per d and 1.2 L of off-gas per L reactor per d. Greater than 80% destruction of the volatile suspended solids was obtained. A simple dynamic process model was constructed to aid in process design and for use in process monitoring and control of a large-scale digester.

Lee, D.D.; Donaldson, T.L.

1985-01-01

20

The Biochemistry of Anaerobic Digestion.  

National Technical Information Service (NTIS)

The investigation sought to determine by means of radioactive tracer techniques, the biochemical mechanisms in the anaerobic degradation of typical organics found in wastes. Two liter laboratory scale digesters were used in all the radioactive tracer work...

J. S. Jeris Y. Chen T. W. Chi Y. Su C. Weng

1970-01-01

21

Biochar from anaerobically digested sugarcane bagasse  

Microsoft Academic Search

This study was designed to investigate the effect of anaerobic digestion on biochar produced from sugarcane bagasse. Sugarcane bagasse was anaerobically digested to produce methane. The digested residue and fresh bagasse was pyrolyzed separately into biochar at 600°C in nitrogen environment. The digested bagasse biochar (DBC) and undigested bagasse biochar (BC) were characterized to determine their physicochemical properties. Although biochar

Mandu Inyang; Bin Gao; Pratap Pullammanappallil; Wenchuan Ding; Andrew R. Zimmerman

2010-01-01

22

Full Scale Conversion of Anaerobic Digesters to Heated Aerobic Digesters.  

National Technical Information Service (NTIS)

Full plant scale experiments were made to determine the effect of heated aerobic digesters on digestion of waste water treatment plant sludge. Existing heated, floating cover equipped, anaerobic digesters, which had failed under excessive paper mill waste...

1972-01-01

23

Anaerobic Digestion of Coffee waste  

Microsoft Academic Search

The anaerobic co-digestion of five different by-products from instant coffee substitutes production was studied in mesophilic conditions. The co-substrate was the excess of sewage sludge from the wastewater treatment plant located in the same coffee factory. Four of the tested wastes produced methane in the range of 0.24-0.28 m3CH4(STP)\\/kgVSinitial . Reduction of 50-73% in total solids and 75-80% in volatile

L. Neves; R. Ribeiro; R. Oliveira

24

ANAEROBIC DIGESTION TECHNOLOGY FOR INDUSTRIAL WASTEWATER TREATMENT  

Microsoft Academic Search

Anaerobic digestion is the most suitable option for the treatment of high strength organic effluents. The presence of biodegradable components in the effluents coupled with the advantages of anaerobic process over other treatment methods makes it an attractive option. This paper reviews the suitability and the status of development of anaerobic reactors for the digestion of selected organic effluents from

Medhat M. A. Saleh; Usama F. Mahmood

2004-01-01

25

High Solid Anaerobic Digestion of Chicken Manure  

Microsoft Academic Search

Anaerobic digestion of high solids chicken manure was conducted in a batch screening assay. Different mixtures of the fresh manure and anaerobically digested sludge or pit manure, resulting in different total solids levels, were incubated at 35°C. The efficiency of organic matter conversion to methane was found to decrease with increasing organic loads to the digesters. The highest solids at

G. Bujoczek; J. Oleszkiewicz; R. Sparling; S. Cenkowski

2000-01-01

26

Agricultural Anaerobic Digesters: Design and Operation.  

National Technical Information Service (NTIS)

The following are discussed: microbial and chemical processes, design and function of the digester system, operational procedure, storage and use of biogas and effluent, and costs of anaerobic digestion and biogas production from dairy barn manure.

S. P. E. Persson H. D. Bartlett A. E. Branding R. W. Regan

1979-01-01

27

Anaerobic sludge digestion with a biocatalytic additive  

SciTech Connect

The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

Ghosh, S.; Henry, M.P.; Fedde, P.A.

1982-01-01

28

Anaerobic Digestion Facility : Environmental Assessment.  

SciTech Connect

Beneficial and adverse environmental impacts associated with the proposed Anaerobic Digestion Facility located near the South Fork Chehalis River, in Boistfort Prairie, Lewis County, Washington, were evaluated. The proposed process would eliminate some animal waste pollution within the area, and also use methane created during the process to power an engine/generator. In addition, the process will permit dairy operators to recycle currently underutilized resources, namely fiber for bedding solids and nutrients for fertilizers. The impacts examined include air quality, water resources, soils, vegetation and wildfire, land use, noise, cultural resources, visual impacts, recreation, and wastes and polychlorinated biphenyls. (ACR)

United States. Bonneville Power Administration. Office of Engineering and Construction.

1984-08-09

29

DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY  

EPA Science Inventory

The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. The fuel cell is being used for this application becau...

30

Propionibacterium species diversity in anaerobic digesters  

Microsoft Academic Search

Phenotypic characteristics of 60 strains ofPropionibacterium isolated from anaerobic hybrid digesters treating landfill leachate and a baker's yeast factory effluent were analysed using numerical taxonomy. With the use of the SSM similarity coefficient, 92% of the anaerobic digester strains were grouped in eight major clusters. The isolates were identified by relating them to specific type strains and comparison of phenotypic

K. H. J. Riedel; T. J. Britz

1993-01-01

31

Inhibition of anaerobic digestion process: a review.  

PubMed

Anaerobic digestion is an attractive waste treatment practice in which both pollution control and energy recovery can be achieved. Many agricultural and industrial wastes are ideal candidates for anaerobic digestion because they contain high levels of easily biodegradable materials. Problems such as low methane yield and process instability are often encountered in anaerobic digestion, preventing this technique from being widely applied. A wide variety of inhibitory substances are the primary cause of anaerobic digester upset or failure since they are present in substantial concentrations in wastes. Considerable research efforts have been made to identify the mechanism and the controlling factors of inhibition. This review provides a detailed summary of the research conducted on the inhibition of anaerobic processes. The inhibitors commonly present in anaerobic digesters include ammonia, sulfide, light metal ions, heavy metals, and organics. Due to the difference in anaerobic inocula, waste composition, and experimental methods and conditions, literature results on inhibition caused by specific toxicants vary widely. Co-digestion with other waste, adaptation of microorganisms to inhibitory substances, and incorporation of methods to remove or counteract toxicants before anaerobic digestion can significantly improve the waste treatment efficiency. PMID:17399981

Chen, Ye; Cheng, Jay J; Creamer, Kurt S

2007-03-30

32

Anaerobic Digestion in Suspended Growth Bioreactors  

Microsoft Academic Search

\\u000a This chapter concerns the principles of suspended growth anaerobic digestion. The fundamentals of anaerobic metabolism of\\u000a organic matter are first presented. This is followed by presentation of anaerobic process stoichiometry and energetics as\\u000a well as kinetics as these are prerequisites for the design of anaerobic processes. The importance of the feed characteristics\\u000a that make a particular substrate medium or feedstock

Gerasimos Lyberatos; Pratap C. Pullammanappallil

33

Anaerobic digestion of alcohol stillage  

SciTech Connect

In the production of ethanol from grain, the distillation step produces a residue of distillers grains or stillage that contains greater than 90% water and is currently dried and used as a cattle feed supplement. Experimental work was carried out on the anaerobic digestion of the stillage to determine the feasibility of using the CH/sub 4/ produced to supply the energy required in the ethanol distillation step. The fermentation characteristics of the stillage were studied, and the amount of CH/sub 4/ produced was determined. Based on an economic analysis, the value of the pressed solids fraction of the stillage as feed is much greater than the potential return from producing CH/sub 4/.

Binder, L.K.

1981-01-01

34

Winery and distillery wastewater treatment by anaerobic digestion  

Microsoft Academic Search

Anaerobic digestion is widely used for wastewater treatment, especially in the food industries. Generally after the anaerobic treatment there is an aerobic post-treatment in order to return the treated water to nature. Several technologies are applied for winery wastewater treatment. They are using free cells or flocs (anaerobic contact digesters, anaerobic sequencing batch reactors and anaerobic lagoons), anaerobic granules (Upflow

R. Moletta

35

Solar pond for heating anaerobic digesters.  

National Technical Information Service (NTIS)

A theoretical analysis and numerical results calculated for solar pond heating anaerobic digesters in Beijing area in China are presented. The effect of temperature rise is evident and rather steady. (Atomindex citation 23:028522)

Song Kehui Li Shensheng

1991-01-01

36

FY 1987 Anaerobic Digestion: Annual Report.  

National Technical Information Service (NTIS)

Anaerobic digestion research is being undertaken by the Department of Energy (DOE) under the field management of the Solar Energy Research Institute (SERI) and is sponsored as part of the Energy from Municipal Waste Research Program to produce methane fro...

1988-01-01

37

Anaerobic digestibility of algal bioethanol residue.  

PubMed

The aim of this work was to investigate anaerobic digestibility of algal bioethanol residue from saccharification and fermentation processes. A series of batch anaerobic digestion tests using saccharification and fermentation residue showed that the maximum methane yields of saccharification residue and fermentation residue were 239 L/kg VS (Volatile Solids) and 283 L/kg VS (Volatile Solids), respectively. Energy recovered by anaerobic digestion of the residue was 2.24 times higher than that from the ethanol produced in the main process. 5-HMF (5-hydroxymethylfurfural), a saccharification byproduct, could retard methanogenesis at over 3g/L however, the inhibition was prevented by increasing cell biomass concentration. Anaerobic digestion of residue has the potential to enhance bioenergy recovery and environmental sustainability of algal bioethanol production. PMID:22364770

Park, Jeong-Hoon; Yoon, Jeong-Jun; Park, Hee-Deung; Lim, Dong Jung; Kim, Sang-Hyoun

2011-12-31

38

DESIGN INFORMATION REPORT: ANAEROBIC DIGESTER MIXING SYSTEMS  

EPA Science Inventory

The design information report discusses the current problems and potential solutions associated with the selection, design, and operation of anaerobic digester mixing systems. The report describes the four major types of mixing systems and presents their advantages and disadvanta...

39

Factors Affecting Acetate Degradation in Anaerobic Digesters.  

National Technical Information Service (NTIS)

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are /ital Methanosarcina barkeri/ and /ital Methanosarcina m...

R. A. Mah D. R. Boone

1988-01-01

40

Anaerobic Digestion. Student Manual. Biological Treatment Process Control.  

ERIC Educational Resources Information Center

|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…

Carnegie, John W., Ed.

41

FERTILITY AND TOXICITY OF POTTING SOILS PREPARED FOR GINNING AND DAIRY WASTES ANAEROBIC DIGESTATE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Methane gas resulting from combining cotton gin trash and dairy manure in a two phase anaerobic digester is easily marketed. Digestate solids are not. This study was conducted to determine anaerobic digestate toxicity and its potential as a soil amendment. The same mixture of dairy manure and cot...

42

Production and Utilization of Methane from Anaerobic Sludge Digestion in US Wastewater-Treatment Plants.  

National Technical Information Service (NTIS)

The goals of this study were: (1) to estimate the energy potential from the anaerobic digestion of municipal sewage sludge, and (2) to assess present digester gas utilization schemes with respect to energy and cost effectiveness. Present use was determine...

1981-01-01

43

The anaerobic digestion of rice straw: A review  

Microsoft Academic Search

The anaerobic digestion of rice straw has been studied for the past century, but the renewable energy potential is barely utilized. Greenhouse gas emissions from rice fields can be substantially reduced if straw is removed. Methane yields ranging from 92 to 404 litres per kilogram of volatile solids have been achieved. Optimal digestion conditions such as pH (6.5 to 8.0),

Wendy Mussoline; Giovanni Esposito; Andrea Giordano; Piet Lens

2012-01-01

44

Anaerobic sludge digestion with a biocatalytic additive. [Lactobacillus acidophilus  

SciTech Connect

Aimed at improving the process operating characteristics of anaerobic digestion for sludge stabilization and SNG production, this study evaluates the effects of a lactobacillus additive under normal, variable, and overload conditions. This whey fermentation product of an acid-tolerant strain of L. acidophilus fortified with CoCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. Data indicate that the biochemical additive increases methane yield, gas production rate, and volatile solids reduction; decreases volatile acids accumulation; enhances the digester buffer capacity; and improves the fertilizer value and dewatering characteristics of the digested residue. Digester capacities could be potentially doubled when the feed is so treated. Results of field tests with six full-scale digesters confirm observations made with bench-scale digesters.

Ghosh, S.; Henry, M.P.; Fedde, P.A.

1982-01-01

45

The rheological behaviour of anaerobic digested sludge.  

PubMed

Producing biogas energy from the anaerobic digestion of wastewater sludge is one of the most challenging tasks facing engineers, because they are dealing with vast quantities of fundamentally scientifically poorly understood and unpredictable materials; while digesters need constant flow properties to operate efficiently. An accurate estimate of sludge rheological properties is required for the design and efficient operation of digestion, including mixing and pumping. In this paper, we have determined the rheological behaviour of digested sludge at different concentrations, and highlighted common features. At low shear stress, digested sludge behaves as a linear viscoelastic solid, but shear banding can occur and modify the apparent behaviour. At very high shear stress, the behaviour fits well to the Bingham model. Finally, we show that the rheological behaviour of digested sludge is qualitatively the same at different solids concentrations, and depends only on the yield stress and Bingham viscosity, both parameters being closely linked to the solids concentration. PMID:21917288

Baudez, J C; Markis, F; Eshtiaghi, N; Slatter, P

2011-09-01

46

Characterization of food waste as feedstock for anaerobic digestion  

Microsoft Academic Search

Food waste collected in the City of San Francisco, California, was characterized for its potential for use as a feedstock for anaerobic digestion processes. The daily and weekly variations of food waste composition over a two-month period were measured. The anaerobic digestibility and biogas and methane yields of the food waste were evaluated using batch anaerobic digestion tests performed at

Ruihong Zhang; Hamed M. El-Mashad; Karl Hartman; Fengyu Wang; Guangqing Liu; Chris Choate; Paul Gamble

2007-01-01

47

Psychrophilic Biofilm Reactors for Anaerobic Digestion.  

National Technical Information Service (NTIS)

Three identical fixed-bed anaerobic reactors (10 l void volume) were used to digest whey permeate at 12 deg. C, 20 deg. C and 35 deg. C. The organic load was kept constant at 7 g COD/l reactor/day in 90 days ''Steady-state'' operation. The overall COD-red...

F. H. Spendler

1987-01-01

48

Comparison of monitoring systems for anaerobic digesters  

Microsoft Academic Search

The deployment of modern smart grid technologies for distributed generation control offers numerous advantages over earlier control systems. Care needs to be taken to choose the correct protocol for the task at hand. This paper compares two systems used for the remote monitoring of anaerobic digesters including their relative costs, bandwidth requirements, implementation, and maintenance issues. The systems discussed are

Greg M. Linder; Stefan Grimberg

2010-01-01

49

Ion Effects in 'Anaerobic Digestion'.  

National Technical Information Service (NTIS)

The report presents results of research on the effects of organic and inorganic ions on the anaerobic waste treatment process. Studied were the effects of various cations, the toxicity of various heavy metals, and the effect of high concentrations of indi...

P. L. McCarty I. J. Kugelman A. W. Lawrence

1964-01-01

50

Purification kinetics of winery wastes by ozonation, anaerobic digestion and ozonation plus anaerobic digestion  

Microsoft Academic Search

The purification of the pollutant organic matter present in winery wastes was investigated by a single ozonation process, by a single anaerobic digestion, and by the combined process constituted by an ozonation stage followed by an anaerobic stage. In these processes, the evolution of the pollutant organic load was followed measuring the chemical oxygen demand (COD). The organic matter eliminated

F. Javier Benitez; Francisco J. Real; Juan L. Acero

1999-01-01

51

Photoenhanced anaerobic digestion of organic acids  

SciTech Connect

This patent describes a process for rapid conversion of organic acids and alcohols in anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion or organic acids and alcohols into methane with low levels of light energy input.

Weaver, P.F.

1990-04-24

52

Anaerobic digestion of municipal solid waste  

SciTech Connect

Filtrate from an anaerobic municipal waste digestion plant at Pompano Beach, Florida, has BOD, COD, and total organic C contents of 1075, 6855, and 1655 mg/L, respectively. The treatment does not inactivate total coliforms; that of the digester slurry and filtrate are 2.3 X 10 to the power of 6 and 1.7 X 10 to the power of 6/100 mL, respectively. The average concentrations of Cr, Cu, Mn, Fe, Ni, and Zn in the filtrate are 0.48, 1.29, 7.29, 32, 0.35, and 11 mg/L, respectively. The filtrate requires treatment prior to discharge.

Dasgupta, A.; Nemerow, N.L.; Farooq, S.; Daly, E.L.Jr.; Sengupta, S.; Gerrish, H.P.; Wong, K.F.

1981-01-01

53

Combining Anaerobic Digestion and Waste-To-Energy  

Microsoft Academic Search

A large fraction of the municipal solid wastes (MSW) stream in the U.S. comprises of natural organic compounds (i.e., food and plant wastes) with high moisture content and low heating value. While these properties are undesirable during the combustion of MSW in waste-to-energy (WTE) plants, they are required for anaerobic digestion (AD). During AD, methane gas is produced that can

KARENA M. OSTREM; KARSTEN MILLRATH; NICKOLAS J. THEMELIS

54

Ultrasound Pretreatment of Sludge for Anaerobic Digestion  

Microsoft Academic Search

\\u000a Ultrasound pretreatment of sludge has been examined in an effort to improve the hydrolysis rate in anaerobic digestion. The\\u000a reactions that resulted from the generation and collapse of cavitation bubbles produced under the acoustic condition can significantly\\u000a modify the substances present in the sludge. The principles of ultrasound that encompass acoustic cavitation and bubble dynamics,\\u000a the mechanisms of biological damage

Kuan Yeow Show; Joo Hwa Tay; Yung-Tse Hung

55

Parasite ova in anaerobically digested sludge  

Microsoft Academic Search

The Metropolitan Sanitary District of Greater Chicago produces anaerobically digested wastewater sludge from a 14-day continuous-flow process maintained at 35 degrees Celcius. Some of the sludge is ultimately applied to strip-mined lands in Central Illinois (Fulton County) as a soil conditioner and fertilizer. Parasitic nematode ova were isolated from freshly processed samples, as well as from samples collected from storage

R. G. Arther; P. R. Fitzgerald; J. C. Fox

1981-01-01

56

Anaerobic digestion of municipal solid waste  

SciTech Connect

A demonstration anaerobic digestion plant has been installed at Pompano Beach, Florida, capable of treating 100 tons per day of municipal solid waste. The suitability of this process and its environmental effects at a full scale operation level is being examined. The study presented and discussed in this paper had as its main objective the characterization of various waste streams and an assessment of their environmental effects if discharged into the environment.

Dasgupta, A.; Nemerow, N.L.; Farooq, S.; Daly, E.L. Jr.; Sengupta, S.; Gerrish, H.P.; Wong, K.F.

1981-03-01

57

Anaerobic sludge digestion with a biocatalytic additive  

Microsoft Academic Search

The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCOâ, (NHâ)âHPOâ, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic

S. Ghosh; M. P. Henry; P. A. Fedde

1982-01-01

58

Anaerobic digestion of slaughterhouse by-products  

Microsoft Academic Search

Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55°C and for some experiments also at 37°C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619dm3kg?1 respectively,

Anette Hejnfelt; Irini Angelidaki

2009-01-01

59

Demonstration-scale evaluation of a novel high-solids anaerobic digestion process for converting organic wastes to fuel gas and compost  

Microsoft Academic Search

Early evaluations of the bioconversion potential for combined wastes such as tuna sludge and sorted municipal solid waste\\u000a (MSW) were conducted at laboratory scale and compared conventional low-solids, stirred-tank anaerobic systems with the novel,\\u000a high-solids anaerobic digester (HSAD) design. Enhanced feedstock conversion rates and yields were determined for the HSAD\\u000a system. In addition, the HSAD system demonstrated superior resiliency to

Christopher J. Rivard; Brian W. Duff; James H. Dickow; Carlton C. Wiles; Nicholas J. Nagle; James L. Gaddy; Edgar C. Clausen

1998-01-01

60

Sequencing mesophilic and thermophilic anaerobic digesters. Final report  

SciTech Connect

This project employed two laboratory bench scale, complete-mix anaerobic sludge digesters arranged in a series configuration. The first digester was operated at 35/sup 0/C (mesophilic) and the second at 50/sup 0/C (thermophilic). A portion of the thermophilic sludge was recycled through an aeration basin. As a comparison to the mesophilic-thermophilic sequencing, a mesophilic-mesophilic digester sequence, without sludge recycle to the aeration basin, was operated in parallel to the test units and loaded at an equivalent rate. Conclusions of this study are as follows: in establishing a thermophilic anaerobic digester, a slow-start procedure, in which the temperature is increased at a rate of 0.6/sup 0/C per day with loading, appears to produce a more stable thermophilic digester in a shorter period of time than a quick-start procedure, in which the temperature is increased rapidly with no loading. Even after a year, the slow-start thermophilic digester proved to be unstable once sequencing began. A greater volatile solids, COD, BOD, and grease reduction with a higher gas production was achieved using a mesophilic-mesophilic sequence, probably, in part, due to the instability (volatile acids in the effluent) of the thermophilic digester in the mesophilic-thermophilic sequence. A greater total kjeldahl N (TKN) and total coliform destruction was achieved in the thermophilic digester, however, poor dewatering characteristics, as indicated by the capillary suction time (CST), and an obnoxious odor were also evident. Other than an increase in effluent suspended solids, the recycle of thermophilic sludge to an aeration basin produced no discernable effect. 9 figs., 3 tabs.

Not Available

1982-12-01

61

Balancing hygienization and anaerobic digestion of raw sewage sludge.  

PubMed

The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery. PMID:23063441

Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

2012-08-01

62

DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM AN ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY  

EPA Science Inventory

The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. he fuel cell is being used for this application becaus...

63

Thermophilic anaerobic digestion of industrial orange waste.  

PubMed

Thermophilic anaerobic digestion of industrial orange waste (pulp and peel) with subsequent aerobic post-treatment of the digestate was evaluated. Methane production potential was first determined in batch assays and the effects of operational parameters such as hydraulic retention times (HRT) and organic loading rates (OLR) on process performance were studied through semi-continuous digestion. In batch assays, methane production potential of about 0.49 m(3) kg(-1) volatile solids (VS)(added waste) was achieved. In semi-continuous digestion, loading at 2.8 kgVS m(-3) d(-1) (2.9 kg total solids (TS) m(-3) d(-1)) and HRT of 26 d produced specific methane yields of 0.6 m(3) kg(-1) VS (added waste) (0.63 m(3) kg(-1) VS(added waste)). Operating at a higher OLR of 4.2 kgVS m(-3) d(-1) (4.4 kg TS m(-3) d(-1)) and 40 d HRT produced 0.5 m(3) of methane kg(-1) VS (added waste) (0.63-0.52 m(3) kg(-1) TS (added waste). Up to 70% of TS of industrial orange waste (11.6% TS) was methanised. Further increase in OLR to 5.6 kg VS m(-3) d(-1) (5.9 kg TS m(-3) d(-1); HRT of 20 d) resulted in an unstable and non-functional digester process shown directly through complete cessation of methanogenesis, drop in methane content, reduced pH and increase in volatile fatty acid (VFA) concentrations, especially acetate and soluble chemical oxygen demand. A pH adjustment (from an initial 3.2 to ca. 8) for the low pH orange waste was necessary and was found to be a crucial factor for stable digester operation as the process showed a tendency to be inhibited due to accumulation of VFAs and decrease in digester pH. Aerobic post-treatment of digestate resulted in removal of ammonia and VFAs. PMID:16865918

Kaparaju, P L N; Rintala, J A

2006-06-01

64

Foaming phenomenon in bench-scale anaerobic digesters.  

PubMed

The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues. PMID:23697241

Siebels, Amanda M; Long, Sharon C

2013-04-01

65

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

ERIC Educational Resources Information Center

This lesson is the second of a two-part series on anaerobic digestion. Topics discussed include classification of digester by function, roof design, and temperature range, mixing systems, gas system components, operational control basics, and general safety considerations. The lesson includes an instructor's guide and student workbook. The…

Arasmith, E. E.

66

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

ERIC Educational Resources Information Center

|This lesson is the second of a two-part series on anaerobic digestion. Topics discussed include classification of digester by function, roof design, and temperature range, mixing systems, gas system components, operational control basics, and general safety considerations. The lesson includes an instructor's guide and student workbook. The…

Arasmith, E. E.

67

State Of The Science On Cogeneration Of Heat And Power From Anaerobic Digestion Of Municipal Biosolids  

EPA Science Inventory

This presentation will report on work underway to inventory facilities currently utilizing biogas from anaerobic digestion and speak with practitioners to learn: techniques for preparing residuals for digestion, methods to use for cleaning biogas (e.g., of siloxane), and how gas...

68

Anaerobic Digestion of Food Waste-recycling Wastewater  

NASA Astrophysics Data System (ADS)

Food waste-recycling (FWR) wastewater was evaluated as feedstock for two-stage anaerobic digestion at different hydraulic retention times (HRTs). The FWR wastewater tested contained high concentrations of organic materials and had chemical oxygen demand (COD) >130 g/L and volatile solids (VS) >55 g/L. Two identical two-stage anaerobic digesters were operated to investigate the performance at six HRTs ranging from 10-25 days. In the acidogenic reactor, the total carbohydrate reduction efficiency and volatile fatty acid production dramatically decreased when acidogenic HRT was <2.5 days (i.e., total two-stage HRT = 15 days). High organic removal ratios of 75.5-85.9% for COD and 68.8-83.6% for VS were achieved throughout the two-stage process. Methane production rate of 1.7-3.6 L-gas/L-reactor.d was observed. These results suggested that two-stage anaerobic process was successful at the laboratory scale with FWR wastewater as feedstock.

Han, Gyuseong; Shin, Seung Gu; Lim, Juntaek; Jo, Minho; Hwang, Seokhwan

2010-11-01

69

Anaerobic digestion Of a Petrochemical Wastewater using the UASB process  

Microsoft Academic Search

Anaerobic digestion of effluent from a petrochemical plant producing terephthalic acid has been tested using two Upflow Anaerobic\\u000a Sludge Blanket (USAB) reactors. The reactors were seeded with two different inocula: one from an anaerobic stabilization pond\\u000a receiving wasted sludge from the aerobic treatment plant of the petrochemical industry (reactor A); the other was an anaerobically\\u000a adapted activated sludge from a

J. P. Guyot; H. Macarie; A. Noyola

1990-01-01

70

Factors affecting acetate degradation in anaerobic digesters  

SciTech Connect

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are )ital Methanosarcina barkeri) and )ital Methanosarcina mazei). One strain of each of these bacteria was selected for this study, in which the effect of molecular hydrogen on acetate dissimilation was examined. We examined the effects that hydrogen concentration had on the active growth of aceticlastic (acetate-splitting) cultures. We found that, during steady-state growth, each of these methanogens ()ital M. barkeri) or )ital M. mazei)) could tolerate a wide range of hydrogen concentrations with little change in their rates of acetate degradation. At hydrogen partial pressures as low as 2 Pa and as high as 800 Pa no change was detected in the growth rate or acetate degradation rate of either of these methanogens. However, we also showed that small amounts of hydrogen were produced or consumed by )ital Methanosarcina) in order to bring the hydrogen concentration in their environment to a pressure of 16 to 92 Pa, similar to that found in anaerobic digestors.

Mah, R.A.; Boone, D.R.

1988-01-01

71

Parasite ova in anaerobically digested sludge  

SciTech Connect

The Metropolitan Sanitary District of Greater Chicago produces anaerobically digested wastewater sludge from a 14-day continuous-flow process maintained at 35 degrees Celcius. Some of the sludge is ultimately applied to strip-mined lands in Central Illinois (Fulton County) as a soil conditioner and fertilizer. Parasitic nematode ova were isolated from freshly processed samples, as well as from samples collected from storage lagoons, using a system of continuous sucrose solution gradients. The mean number of ova per 100 g of dry sludge was 203 Ascaris spp., 173 Toxocara spp., 48 Toxascaris leonina, and 36 Trichuris spp. An assessment of the viability of these ova was determined by subjecting the ova to conditions favorable for embryonation. Recovered ova were placed in 1.5% formalin and aerated at 22 degrees Celcius for 21 to 28 days. Development of ova isolated from freshly digested sludge occurred in 64% of the Ascaris spp., 53% of the Toxocara, 63% of the Toxascaris leonina, and 20% of the Trichuris spp. Viability was also demonstrated in ova recovered from sludge samples held in storage lagoons for a period of up to 5 years; embryonation occurred in 24% of the Ascaris spp., 10% of the Toxocara spp., 43% of the Toxascaris leonina, and 6% of the Trichuris spp. (Refs. 24).

Arther, R.G.; Fitzgerald, P.R.; Fox, J.C.

1981-08-01

72

Multiple-stage anaerobic digestion system  

SciTech Connect

The purpose of this study is to develop a new process for the stabilization of municipal sludge produced at the Allegheny County Sanitary Authority wastewater treatment plant in Pittsburgh, Pennsylvania. A multiple-stage digestion process is sought to provide good removal efficiency of high concentration of sludge and to perform high methane production. The process primarily consists of three stages of anaerobic digestion. Stage 1 is for hydrolysis and acidification and stage 2 is for acidification and methanation; both digesters are operated in the mesophilic temperature range. The last stage is for methanation which is controlled in the thermophilic range. The multiple-stage system (MS) was operated at different solids retention time (SRT) of 15, 9, and 20 days. For comparison to the performance of the multiple-stage system a conventional single-stage system (SS) was also operated at the same conditions. The COD removal, solids reduction, and the methane yield of the multiple-stage system were much greater than the single-stage system at all of the different SRT. Moreover, the results of the different SRT of the multiple-stage system study showed that a SRT of 15 days has the best performance. The maximum VS removal rates are 67% of MS and 50% of SS; and the methane yields are 6.72 SCF CH/sub 4//lb VS added of MS and 3.95 SCF CH/sub 4//lb VS added of SS with VS loading of 0.15 lb/ft/sup 3/-day at a 15 days SRT. These methane yields are equivalent to 89% and 67% biogas conversion from the removed VS (based on 75% of the sludge VS is biodegradable), respectively, for the multiple-stage and the single-stage systems.

Lin, L.Y.

1985-01-01

73

Anaerobic digestion of water hyacinth and sludge  

SciTech Connect

The Institute of Gas Technology (IGT) has been operating an experimental test unit (ETU) at the Walt Disney World (WDW) wastewater treatment plant to demonstrate the conversion of water hyacinth and sludge to methane in a solids concentrating (SOLCON) digester. Results from 2 years to operation have confirmed earlier laboratory observations that this digester achieves higher methane yields and solids conversion than those observed in continuous stirred tank reactors. Methane yields as high as 0.49 m/sup 3/ kg/sup -1/ (7.9 SCF/lb) volatile solids added have been obtained during steady-state operation on a blend of water hyacinth and sludge. 9 refs., 5 figs., 5 tabs.

Biljetina, R.; Srivastava, V.J.; Chynoweth, D.P.; Hayes, T.D.

1986-01-01

74

INCREASE OF INDICATOR ORGANISMS FOLLOWING ANAEROBIC DIGESTION AND CENTRIFUGE DEWATERING.  

EPA Science Inventory

The Water Environment Research Foundation (WERF) recently published a report titled ?Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges?. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bac...

75

Anaerobic Digestion: Principles and Practices for Biogas Systems.  

National Technical Information Service (NTIS)

The report is part of a joint global research, development and demonstration effort of the United Nations Development Programme and the World Bank. It explores the history, technology, and applications of anaerobic digestion, the biological process by whi...

C. G. Gunnerson D. C. Stuckey

1986-01-01

76

Biogas recovery from microwave heated sludge by anaerobic digestion  

Microsoft Academic Search

Biogas generated from sewage sludge, livestock waste, and food waste by anaerobic digestion is a valuable renewable energy\\u000a resource. However, conventional anaerobic digestion is not an efficient process. A long hydraulic retention time and low biogas\\u000a recovery rate hinder the applications of those resources. An effective pretreatment method to destroy sludge microbial cells\\u000a has been one of the major concerns

Wei Qiao; Wei Wang; CuiPing Zhu; ZhongZhi Zhang

2010-01-01

77

Industrial symbiosis: Corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion.  

PubMed

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage. Biotechnol. Bioeng. 2013;110: 2624-2632. © 2013 Wiley Periodicals, Inc. PMID:23568780

Wood, Brandon M; Jader, Lindsey R; Schendel, Frederick J; Hahn, Nicholas J; Valentas, Kenneth J; McNamara, Patrick J; Novak, Paige M; Heilmann, Steven M

2013-04-26

78

Modelling of the mesophilic anaerobic co-digestion of olive mill wastewater with olive mill solid waste using anaerobic digestion model No. 1 (ADM1).  

PubMed

The anaerobic digestion model No. 1 (ADM1), conceived by the international water association (IWA) task group for mathematical modelling of anaerobic digestion processes is a structured generic model which includes multiples steps describing biochemical and physicochemical processes encountered in the anaerobic degradation of complex organic substrates and a common platform for further model enhancement and validation of dynamic simulations for a variety of anaerobic processes. In this study the ADM1 model was modified and applied to simulate the mesophilic anaerobic co-digestion of olive mill wastewater (OMW) with olive mill solid waste (OMSW). The ADM1 equations were coded and implemented using the simulation software package MATLAB/Simulink. The most sensitive parameters were calibrated and validated using updated experimental data of our previous work. The results indicated that the ADM1 model could simulate with good accuracy: gas flows, methane and carbon-dioxide contents, pH and total volatile fatty acids (TVFA) concentrations of effluents for various feed concentrations digested at different hydraulic retention times (HRTs) and especially at HRTs of 36 and 24 days. Furthermore, effluent alkalinity and ammonium nitrogen were successfully predicted by the model at HRTs of 12 and 24 days for some feed concentrations. PMID:18187320

Boubaker, Fezzani; Ridha, Ben Cheikh

2008-01-09

79

Potential of anaerobic digestion for mitigation of greenhouse gas emissions and production of renewable energy from agriculture: barriers and incentives to widespread adoption in Europe.  

PubMed

The paper considers the role of anaerobic digestion in promoting good agricultural practice on farms and the contribution this would make to reducing the environmental impacts associated with manure management. There are no regulatory drivers to promote the use of digestion in Europe, and the technology has only been widely adopted where economic drivers and coherent policies have been implemented at a national level. These measures have included direct subsidy on the energy price paid for "green electricity", and exemption of tax when biogas is used as a vehicle fuel. In those countries where financial incentives are not available or where a financial penalty is incurred through the regulatory regime, the uptake of digestion has been poor. Even with subsidies, digestion of animal manures as a single substrate is not common, and countries with successful schemes have achieved this either by permitting the import of wastes onto the farm or offering bonus subsidies for the use of energy crops. Both of these measures improve the energy efficiency of the process by increasing the volumetric methane production, although concerns are expressed that attention could concentrate on energy production at the expense of improving manure management. PMID:17564382

Banks, C J; Salter, A M; Chesshire, M

2007-01-01

80

Fate of 17B-estradiol in anaerobic lagoon digesters  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fate of [14C]17B-estradiol ([14C]E2) was monitored for 42 d in triplicate 10 L anaerobic digesters. Total radioactive residues (TRR) decreased rapidly in the liquid layer of the digesters and reached a steady-state value of 19-24% of the initial dose after 4 days. LC/MS/MS analyses of the liqu...

81

Anaerobic co-digestion of dairy manure and sugar beets  

Microsoft Academic Search

Batch and continuously fed experiments were conducted with laboratory-scale digesters to evaluate the performance of anaerobic co-digestion of dairy manure and sugar beets under thermophilic temperatures. The sugar beets were divided into two portions of tops and roots. Four types of influent feedstocks were utilized: 100% dairy manure, a mixture of beet tops, a mixture of whole beets (tops and

K. Umetsu; S. Yamazaki; T. Kishimoto; J. Takahashi; Y. Shibata; C. Zhang; T. Misaki; O. Hamamoto; I. Ihara; M. Komiyama

2006-01-01

82

Demonstration of anaerobic digesters in developing countries. Part II  

Microsoft Academic Search

The objectives of the evaluations were to identify designs and effectiveness analyses of type biogas digesters that are practical to construct, operate, and maintain within the economic affordability of developing countries. Describing in detail the needs of a particular people in their particular cultural environment is extremely difficult because it necessarily involves their value judgements. The type anaerobic digesters for

1979-01-01

83

Heat and energy requirements in thermophilic anaerobic sludge digestion  

Microsoft Academic Search

The heating requirements of the thermophilic anaerobic digestion process were studied. Biogas production was studied in laboratory experiments at retention times from 1 to 10 days. The data gathered in the experiments was then used to perform a heat and energy analysis. The source of heat was a conventional CHP unit system. The results showed that thermophilic digestion is much

G. D. Zupan?i?; M. Roš

2003-01-01

84

Anaerobic digestion of polyelectrolyte flocculated waste activated sludge  

Microsoft Academic Search

This work examined how adding one of three polyelectrolyte flocculants (T3052: cationic, T2000: non-ionic, and T1052: anionic) affected the anaerobic digestion of wastewater sludge. Methane production, floc characteristics (morphology and ?-potential) and process parameters (soluble chemical oxygen demands (SCODs) and reductive potentials) were monitored along the digestion tests. The digestion rates of T2000- and T1052-conditioned sludge resembled that for original

C. P. Chu; D. J. Lee; Bea-Ven Chang; C. H. You; C. S. Liao; J. H. Tay

2003-01-01

85

Anaerobic digestion of fungally pre-treated wine distillery wastewater  

Microsoft Academic Search

The combination of fungal pre-treatment with Trametes pubescens and anaerobic digestion were tested for the removal of chemical oxygen demand (COD) and phenolic compounds from wine distillery wastewater. The COD removal efficiency after fungal pre-treatment reached 53.3%. During digestion, pH buffering was achieved using CaCO3 and K2HPO4. This provided a stable environment inside digester for efficient and time-independent COD removal.

Xolisa Melamane; Roman Tandlich; Jo Burgess

2007-01-01

86

Biogasification of sorghum in a novel anaerobic digester  

SciTech Connect

The Institute of Gas Technology (IGT) conducted pilot-scale anaerobic digestion experiments with ensiled sorghum in a 160 ft/sup 3/ digester at the experimental test unit (ETU) facility at the Walt Disney World Resort Complex in Florida. The study focused on improving bioconversion efficiencies and process stability by employing a novel reactor concept developed at IGT. Steady-state performance data were collected from the ETU as well as from a laboratory-scale conventional stirred tank reactor (CSTR) at loading rates of 0.25 and 0.50 lb organic matter/ft/sup 3/-day at mesophilic and thermophilic temperatures, respectively. This paper will describe the ETU facility, novel digester design and operating techniques, and the results obtained during 12 months of stable and uninterrupted operation of the ETU and the CSTR which showed that methane yields anad rates from the ETU were 20% to 50% higher than those of the CSTR. 10 refs., 7 figs., 5 tabs.

Srivastava, V.J.; Biljetina, R.; Isaacson, H.R.; Hayes, T.D.

1987-01-01

87

Characterization of food waste as feedstock for anaerobic digestion.  

PubMed

Food waste collected in the City of San Francisco, California, was characterized for its potential for use as a feedstock for anaerobic digestion processes. The daily and weekly variations of food waste composition over a two-month period were measured. The anaerobic digestibility and biogas and methane yields of the food waste were evaluated using batch anaerobic digestion tests performed at 50 degrees C. The daily average moisture content (MC) and the ratio of volatile solids to total solids (VS/TS) determined from a week-long sampling were 70% and 83%, respectively, while the weekly average MC and VS/TS were 74% and 87%, respectively. The nutrient content analysis showed that the food waste contained well balanced nutrients for anaerobic microorganisms. The methane yield was determined to be 348 and 435 mL/gVS, respectively, after 10 and 28 days of digestion. The average methane content of biogas was 73%. The average VS destruction was 81% at the end of the 28-day digestion test. The results of this study indicate that the food waste is a highly desirable substrate for anaerobic digesters with regards to its high biodegradability and methane yield. PMID:16635571

Zhang, Ruihong; El-Mashad, Hamed M; Hartman, Karl; Wang, Fengyu; Liu, Guangqing; Choate, Chris; Gamble, Paul

2006-04-24

88

Improvement of fruit and vegetable waste anaerobic digestion performance and stability with co-substrates addition.  

PubMed

The effect of fish waste (FW), abattoir wastewater (AW) and waste activated sludge (WAS) addition as co-substrates on the fruit and vegetable waste (FVW) anaerobic digestion performance was investigated under mesophilic conditions using four anaerobic sequencing batch reactors (ASBR) with the aim of finding the better co-substrate for the enhanced performance of co-digestion. The reactors were operated at an organic loading rate of 2.46-2.51 g volatile solids (VS)l(-1)d(-1), of which approximately 90% were from FVW, and a hydraulic retention time of 10 days. It was observed that AW and WAS additions with a ratio of 10% VS enhanced biogas yield by 51.5% and 43.8% and total volatile solids removal by 10% and 11.7%, respectively. However FW addition led to improvement of the process stability, as indicated by the low VFAs/Alkalinity ratio of 0.28, and permitted anaerobic digestion of FVW without chemical alkali addition. Despite a considerable decrease in the C/N ratio from 34.2 to 27.6, the addition of FW slightly improved the gas production yield (8.1%) compared to anaerobic digestion of FVW alone. A C/N ratio between 22 and 25 seemed to be better for anaerobic co-digestion of FVW with its co-substrates. The most significant factor for enhanced FVW digestion performance was the improved organic nitrogen content provided by the additional wastes. Consequently, the occurrence of an imbalance between the different groups of anaerobic bacteria which may take place in unstable anaerobic digestion of FVW could be prevented. PMID:19117663

Bouallagui, H; Lahdheb, H; Ben Romdan, E; Rachdi, B; Hamdi, M

2008-12-30

89

Anaerobic Digesters Change the Phosphorus Leaching Behavior of Dairy Manure  

NASA Astrophysics Data System (ADS)

This study analyzed how anaerobic digestion of dairy manure might change the amount, form, and rate of phosphorus (P) leached by rainfall. Anaerobic digestion has become an increasingly popular manure management option because it generates methane that can be used to make energy, but little is known about the behavior of P when digested manure is applied to fields. Leaching experiments were performed using simulated rainfall on digester influent (undigested manure) and effluent (digested manure) collected from a dairy farm near Ithaca, NY. A previously published manure-P model was applied to the experimental data to quantify rates of P leaching. Dissolved P-leaching from digested and undigested manures were similar to each other, although digested manures appear to generally leach more dissolved P. Interestingly, both digester influent and effluent leached dissolved P more rapidly and in greater quantities than fresh manure, i.e., manure from a dairy barn floor. It is suggested that the key difference between the liquid manures in this study and “fresh” manure is that fresh manure has a higher solids content, i.e., it is less liquid than the manure used in anaerobic digesters. The findings of this study suggest that it is important to avoid field spreading of liquid manures when rainfall is imminent or fields are wet in order to prevent nonpoint P loading to streams and lakes.

Marjerison, R.; Gooch, C.; Pronto, J.; Walter, M. T.

2009-12-01

90

Application of Anaerobic Digestion Model No. 1 for describing anaerobic digestion of grass, maize, green weed silage, and industrial glycerine.  

PubMed

Anaerobic digestion of organic waste plays an important role for the development of sustainable energy supply based on renewable resources. For further process optimization of anaerobic digestion, biogas production with the commonly used substrates, grass, maize, and green weed silage, together with industrial glycerine, were analyzed by the Weender analysis/van Soest method, and a simulation study was performed, based on the International Water Association's (IWA) Anaerobic Digestion Model No. 1 (ADM1). The simplex algorithm was applied to optimize kinetic constants for disintegration and hydrolysis steps for all examined substrates. Consequently, new parameters were determined for each evaluated substrate, tested against experimental cumulative biogas production results, and assessed against ADM1 default values for disintegration and hydrolysis kinetic constants, where the ADM1 values for mesophilic high rate and ADM1 values for solids were used. Results of the optimization lead to a precise prediction of the kinetics of anaerobic degradation of complex substrates. PMID:23131640

Biernacki, Piotr; Steinigeweg, Sven; Borchert, Axel; Uhlenhut, Frank

2012-10-13

91

SALE OF SURPLUS DIGESTER AND LANDFILL GAS TO PUBLIC UTILITIES  

EPA Science Inventory

Methane gas produced by anaerobic digestion of wastewater sludge can be upgraded to pipeline quality and sold to a public utility for injection into a natural gas distribution system. Upgrading the gas typically involves treatment for removal of carbon dioxide and hydrogen sulfid...

92

Anaerobic Digestion and Combined Heat and Power Study  

SciTech Connect

One of the underlying objectives of this study is to recover the untapped energy in wastewater biomass. Some national statistics worth considering include: (1) 5% of the electrical energy demand in the US is used to treat municipal wastewater; (2) This carbon rich wastewater is an untapped energy resource; (3) Only 10% of wastewater treatment plants (>5mgd) recover energy; (4) Wastewater treatment plants have the potential to produce > 575 MW of energy nationwide; and (5) Wastewater treatment plants have the potential to capture an additional 175 MW of energy from waste Fats, Oils and Grease. The WSSC conducted this study to determine the feasibility of utilizing anaerobic digestion and combined heat and power (AD/CHP) and/or biosolids gasification and drying facilities to produce and utilize renewable digester biogas. Digester gas is considered a renewable energy source and can be used in place of fossil fuels to reduce greenhouse gas emissions. The project focus includes: (1) Converting wastewater Biomass to Electricity; (2) Using innovative technologies to Maximize Energy Recovery; and (3) Enhancing the Environment by reducing nutrient load to waterways (Chesapeake Bay), Sanitary Sewer Overflows (by reducing FOG in sewers) and Greenhouse Gas Emissions. The study consisted of these four tasks: (1) Technology screening and alternative shortlisting, answering the question 'what are the most viable and cost effective technical approaches by which to recover and reuse energy from biosolids while reducing disposal volume?'; (2) Energy recovery and disposal reduction potential verification, answering the question 'how much energy can be recovered from biosolids?'; (3) Economic environmental and community benefit analysis, answering the question 'what are the potential economic, environmental and community benefits/impacts of each approach?'; and (4) Recommend the best plan and develop a concept design.

Frank J. Hartz Rob Taylor Grant Davies

2011-12-30

93

Decentralized application of anaerobic digesters in small poultry farms: performance analysis of high rate self mixed anaerobic digester and conventional fixed dome anaerobic digester.  

PubMed

Biomethanation of poultry litter was studied in conventional fixed dome anaerobic digester (CFDAD) and high rate self mixed anaerobic digester (SMAD) for possible decentralized application in poultry farms generating litter in the range of 500 kg/day. The performance of CFDAD and SMAD was compared. The study revealed that optimized hydraulic residence time (HRT), volatile solids (VS) loading rate, VS reduction, methane yield was 24 days, 4.0 kg VS/m(3)/day, 64%, 0.15 m(3)/(kg VS fed) and 40 days, 2.15 kg/m(3)/day, 42%, 0.083 m(3)/(kg VS fed) for SMAD and CFDAD, respectively. Better results with SMAD could be attributed to specific design features and intermittent mixing of the digester contents due to self-mixing mechanism. Preliminary cost estimates revealed that installation of SMAD would be remunerative for the farmer in terms of biogas and bio-manure. PMID:23867531

Rao, A Gangagni; Gandu, Bharath; Sandhya, K; Kranti, K; Ahuja, Shruti; Swamy, Y V

2013-06-28

94

Anaerobic digestion: principles and practices for biogas systems. World Bank technical paper  

Microsoft Academic Search

The report is part of a joint global research, development, and demonstration effort of the United Nations Development Programme and the World Bank. It explores the history, technology, and applications of anaerobic digestion, the biological process by which organic materials are degraded in the absence of oxygen to produce a combustible gas, methane (CHâ), and carbon dioxide (COâ). The process

C. G. Gunnerson; D. C. Stuckey

1986-01-01

95

Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Annual report  

SciTech Connect

The findings of the characterization and environmental studies of an anaerobic digestion plant at Pompano Beach are presented. This 100 ton/day proof of concept plant which produces methane from municipal waste was built on an existing shredding and landfill site. The following aspects of the plant are covered: gas quality, airborne particulates, solid/liquid phases, microbiology, and leaching. (MHR)

Sengupta, S.; Wong, K.F.V.; Gerrish, H.P.; Nemerow, N.; Voorhees, S.A.; Daly, E.L. Jr.

1982-03-01

96

Potential errors in the quantitative evaluation of biogas production in anaerobic digestion processes  

Microsoft Academic Search

Errors that are commonly made in the quantification of biogas from anaerobic digestion experiments were investigated.For liquid displacement gasometers where a barrier solution separates the biogas and the atmosphere, inaccuracy due to gas diffusion was examined experimentally. Acidified saturated saline solution was the most suitable barrier solution, as biogas characteristics changed least with time. Using acidified or tap water caused

Mark Walker; Yue Zhang; Sonia Heaven; Charles Banks

2009-01-01

97

Effect of metals on anaerobic digestion of water hyacinth-cattle dung  

Microsoft Academic Search

The effect of several salts, FeCl3, NiCl2, CoCl2, CuCl2, and ZnCl2, on anaerobic digestion of water hyacinth-cattle dung was examined. Among the salts studied, FeCl3 caused a more than 60% increase in gas production with a high methane content.

Vikram B. Patel; Anami R. Patel; Manisha C. Patel; Datta B. Madamwar

1993-01-01

98

Experimental digester facility modifications and digester gas upgrading research  

SciTech Connect

The Institute of Gas Technology (IGT) has been participating in an experimental program at the Community Waste Research Facility (CWRF) located at the Walt Disney World Resort Complex, Orlando, Florida. Four institutions have formed a team to provide solutions to community waste treatment and disposal programs. Of primary importance to this research effort is the implementation of low-cost, energy-efficient waste treatment and recovery technologies and the net production of energy (methane) from biomass and waste resources. The production of methane is being studied in a novel, high-rate digester. During 1988, we were responsible for modifying the Experimental Test Unit (ETU) to permit dry solids feeding of refuse-derived fuel (RDF) and for conducting bench-scale experiments to evaluate techniques for efficient removal of carbon dioxide produced during anaerobic digestion.

Srivastava, V.J.; Biljetina, R.; Akin, C.

1989-01-01

99

[Start-up of a thermophilic anaerobic sludge digester].  

PubMed

Anaerobic digestion is one of the most widely-used technologies of the sludge reduction and stabilization, in which thermophilic digestion has advantage of fast stabilization. But it is lack of operation experience in China. Thus start-up of a thermophilic anaerobic sludge digester treating excess activated sludge was investigated. The digester was an internal circulation anaerobic sludge digester. It belongs to upflow reactor and its hydrodynamic conditions can be controlled by backflow biogas. A multistep strategy was applied to the start-up to enhance anaerobic bacteria to adapt the changes of temperature, reactor and treated sludge, including: to feed the digester with easily-degraded glucose to enhance bacteria reproduce at the first beginning with COD organic loading of 2.4 kg/(m3 x d); to accelerate the internal circulation; to control pH within a optimal range; to gradually increase excess sludge flow rate as well as to initiate pydrohydrolysis to enhance hydrolysis. The start-up took 63 days and when it finished, the VSS organic loading reached 1.60 kg/(m3 x d), the average VSS biogas rate was 0.51 L/g, i. e. 15.3 m3/m3 sludge (96% water content), VSS and SS removals were 60.8% and 45.8%. This shows that the strategy is valid. PMID:21528577

Wu, Jing; Zhao, Peng-Juan; Tian, Lei; Shi, Lin; Shi, Han-Chang; Jiang, Yan

2011-02-01

100

Computer simulation of control strategies for optimal anaerobic digestion.  

PubMed

Three previously published control strategies for anaerobic digestion were implemented in Simulink/Matlab using Anaerobic Digestion Model No. 1 (ADM1) to model the biological process. The controllers' performance were then simulated and evaluated based on their responses from five different types of process scenarios i.e. start-up and steady state performance as well as disturbances from concentration, pH and ammonia in the inflow. Of the three evaluated control strategies, the extremum-seeking variable gain controller gave the best overall performance. However, a proportional feedback controller based on the pH-level, used as a reference case in the evaluation, proved to give as good results as the extremum-seeking variable gain controller but with a lower wear on the pump. It was therefore concluded that a fast proportional control of the reactor pH is a key element for optimally controlling a low-buffering anaerobic digestion process. PMID:23202565

Strömberg, S; Possfelt, M O; Liu, J

2013-01-01

101

Anaerobic digestion model no. 1-based distributed parameter model of an anaerobic reactor: I. Model development.  

PubMed

This work presents a distributed parameter model of the anaerobic digestion process. The model is based on the Anaerobic digestion model no. 1 (ADM1) and was developed to simulate anaerobic digestion process in high-rate reactors with significant axial dispersion, such as in upflow anaerobic sludge bed (UASB) reactors. The model, which was named ADM1d, combines ADM1's kinetics of biomass growth and substrate transformation with axial dispersion material balances. ADM1d uses a hyperbolic tangent function to describe biomass distribution within a one compartment model. A comparison of this approach with a two-compartment, sludge bed - liquid above the bed, model showed similar simulation results while the one-compartment model had less equations. A comparison of orthogonal collocation and finite difference algorithms for numerical solution of ADM1d showed better stability of the finite difference algorithm. PMID:17881223

Mu, S J; Zeng, Y; Wu, P; Lou, S J; Tartakovsky, B

2007-09-18

102

Anaerobic digestion of secondary residuals from an anaerobic bioreactor at a brewery to enhance bioenergy generation  

Microsoft Academic Search

Many beer breweries use high-rate anaerobic digestion (AD) systems to treat their soluble high-strength wastewater. Biogas\\u000a from these AD systems is used to offset nonrenewable energy utilization in the brewery. With increasing nonrenewable energy\\u000a costs, interest has mounted to also digest secondary residuals from the high-rate digester effluent, which consists of yeast\\u000a cells, bacteria, methanogens, and small (hemi)cellulosic particles. Mesophilic

Benjamin T. Bocher; Matthew T. Agler; Marcelo L. Garcia; Allen R. Beers; Largus T. Angenent

2008-01-01

103

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

Spirulina maxima algal biomass could be used as the sole nutrient for the production of biogas by anaerobic digestion process. It is relatively simple to adapt the municipal sewage sludge to this new substrate. The adapted sludge is very stable. Under nonoptimal conditions, the methane yield and productivity obtained were 0.26 m/sup 3//(kg VS added day) and 0.26 m/sup 3//(kg VS added day), respectively, with the semicontinuous, daily fed, anaerobic digestion having loading rate of 0.97 kg VS/(m/sup 3/ day), retention time of 33 days and temperature of 30/sup 0/C.

Rejean Samson; Anh LeDuy

1982-08-01

104

Anaerobic Digestion of Aquatic Plant Biomass.  

National Technical Information Service (NTIS)

This document presents the results of an experimental study on the methanic anaerobic fermentation of two algae (Enteromorpha intestinalis, Ulva lactuca) and one superior aquatic plant (Lemna sp.): analysis of the chemical characteristics of the biomass, ...

F. Brouard

1983-01-01

105

Waste heat utilization in an anaerobic digestion system  

NASA Astrophysics Data System (ADS)

Anaerobic digestion has great potential as an energy source. Not only does it provide an effective method for waste mitigation, but it has the potential to generate significant quantities of fuel and electricity. In order to ensure efficient digestion and biomass utilization, however, the system must be continuously maintained at elevated temperatures. It is technically feasible to supplement such a system with outside energy, but it is more cost effective to heat the system using only the produced biogas. While there is considerable literature covering the theory of anaerobic digestion, there are very few practical studies to show how heat utilization affects system operation. This study considers the effect of major design variables (i.e. heat exchanger efficiencies and biogas conditioning) on promoting a completely self-sustaining digestion system. The thesis considers a real world system and analyzes how it can be improved to avoid the need of an external energy source.

Boissevain, Brett

106

Anaerobic Digestion Technology. Quarterly Progress Meeting, Ithaca, New York, June 20--22, 1977.  

National Technical Information Service (NTIS)

Summaries of the current status of research on anaerobic digestion technology are presented. The fourteen projects reported on range in subject matter from the fundamentals and mechanisms of anaerobic digestion to the construction and operation of demonst...

1977-01-01

107

Anaerobic sludge digestion in the presence of lactobacillus additive  

SciTech Connect

A laboratory evaluation of a lactobacillus fermentation product was performed to study its effects as an additive on the anaerobic digestion of sewage sludge under conventional and overloaded high-rate conditions. The overloaded conditions were those experienced in commercial municipal digesters. It was concluded from this work that the use of the additive at low concentrations permits digester operation at least up to double the loading of untreated digesters and at higher methane yields and volatile solids reductions without affecting effluent quality. The additive also imparts iproved digester stability and rapid response to loading rate and detention time excursions and upsets. The beneficial effets of the additive observed in the laboratory remain to be established with other feeds such as biomass, and in large-scale commercial digestion tests that are now in progress.

Ghosh, S.; Klass, D.L.

1980-01-01

108

Comparison between ozone and ultrasound disintegration on sludge anaerobic digestion.  

PubMed

This paper deals with the comparison of ultrasound (mechanical) and ozone (chemical) pre-treatment on the performances of excess sludge semi-continuous digestion. Sludge solubilisation has been investigated by varying specific energy input. For each pre-treatment, long anaerobic digestion tests were carried out by two parallel digesters: one reactor, as control unit, was fed with untreated waste activated sludge, and the other one was fed with disintegrated sludge. To evaluate and compare the efficacy of both pre-treatments, the specific energy was maintained approximately the same. The digestion tests were carried out to investigate the feasibility of anaerobic digestion performance (total biogas production, volatile solids removal, sludge dewaterability) and to assess the heat balance. Results obtained from the digestion of sonicated sludge at 4% disintegration degree (? 2500 kJ/kg TS) showed that the ultrasound pre-treatment may be effective both in increasing VS destruction (+19%) and cumulative biogas production (+26%). On the contrary, the digestion test with ozonized sludge (ozone dose of 0.05 g O(3)/g TS corresponding to ? 2000 kJ/kg TS) did not indicate a significant improvement on the digestion performances. By doubling the ozone dose an improvement in the organics removal and cumulative biogas production was observed. Relevant differences in terms of colloidal charge and filterability were discussed. PMID:20719427

Braguglia, C M; Gianico, A; Mininni, G

2010-08-16

109

Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).  

PubMed

The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale. PMID:15607176

Blumensaat, F; Keller, J

2005-01-01

110

Modeling anaerobic digestion of aquatic plants by rumen cultures: Cattail as an example  

Microsoft Academic Search

Despite of the significance of the anaerobic digestion of lignocellulosic materials, only a limited number of studies have been carried out to evaluate the lignocellulosic digestion kinetics, and information about the modeling of this process is limited. In this work, a mathematical model, based on the Anaerobic Digestion Model No.1 (ADM1), was developed to describe the anaerobic conversion of lignocellulose-rich

Bai-Hang Zhao; Zheng-Bo Yue; Bing-Jie Ni; Yang Mu; Han-Qing Yu; Hideki Harada

2009-01-01

111

Assessing amendment and fertilizing properties of digestates from anaerobic digestion through a comparative study with digested sludge and compost.  

PubMed

Digestate, with biogas represents the final products of anaerobic digestion (AD). The methane-rich biogas is used to produce electricity and heat, whereas the digestate could be valorized in agriculture. Contrarily to well-recognized biomasses such as digested sludge and compost, the properties of the digestate are not well known and its agricultural use remains unexplored. In this work, a first attempt to study the agronomic properties of digestates was performed by comparing the chemical, spectroscopic, and biological characteristics of digestates with those of compost and digested sludge, used as reference organic matrices. A total of 23 organic matrices were studied, which include eight ingestates and relative digestates, three composts, and four digested sludges. The analytical data obtained was analyzed using principal component analysis to better show in detail similarities or differences between the organic matrices studied. The results showed that digestates differed from ingestates and also from compost, although the starting organic mix influenced the digestate final characteristics. With respect to amendment properties, it seems that biological parameters, more than chemical characteristics, were more important in describing these features. In this way, amendment properties could be ranked as follows: compost?digestate>digested sludge?ingestate. As to fertilizer properties, AD allowed getting a final product (digestate) with very good fertilizing properties because of the high nutrient content (N, P, K) in available form. In this way, the digestate appears to be a very good candidate to replace inorganic fertilizers, also contributing, to the short-term soil organic matter turnover. PMID:20825964

Tambone, Fulvia; Scaglia, Barbara; D'Imporzano, Giuliana; Schievano, Andrea; Orzi, Valentina; Salati, Silvia; Adani, Fabrizio

2010-09-09

112

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

Samson, R.; LeDuy, A.

1982-08-01

113

Thermophilic Anaerobic Digester Performance Under Different Feed-Loading Frequency  

NASA Astrophysics Data System (ADS)

The effect of feed-loading frequency on digester performance was studied on a thermophilic anaerobic digester with a working volume of 27.43 m3. The digester was fed 0.93 m3 of chicken-litter slurry/d, containing 50.9 g/L chemical oxygen demand. The treatments were loading frequencies of 1, 2, 6, and 12 times/d. The hourly pH, biogas production, and methane percent of the biogas were less stable at lower feed frequencies. There was no statistical difference among treatments in methanogenic activity. The feed-loading frequency of six times per day treatment provided the greatest biogas production.

Bombardiere, John; Espinosa-Solares, Teodoro; Domaschko, Max; Chatfield, Mark

114

Anaerobic digestion of excess activated sludge with ozone pretreatment  

Microsoft Academic Search

Source minimization of excess sludge production by economical means can be considered an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for a process that combines the oxidative ozone pretreatment with anaerobic sludge digestion are described. The ozone pretreatment solubilized around 19% and 37% of the solids at

R. Goel; T. Tokutomi; H. Yasui

2003-01-01

115

Study of Resource Recovery and Epidemiology in an Anaerobic Digester.  

National Technical Information Service (NTIS)

Three 4-liter packed bed anaerobic digesters were fabricated and operated at 35 degrees C, pH around 7, and hydraulic retention time (HRT) of 20, 10 and 5 days to study the resource recovery and epidemiology in a controlled ecological life support system ...

K. Y. Li S. Cao M. D. Hunt X. Fu

1995-01-01

116

Anaerobic digestion of solid wastes of cane sugar industry  

Microsoft Academic Search

The cane sugar manufacturing industry generates large quantities of lignocellulosic solid wastes, namely bagasse and cachaza. Bagasse is the fibrous residue of the cane after extracting the juice. Cachaza is the filter cake of the precipitated insoluble sugars. This research investigates the feasibility of anaerobic digestion of a mixture of bagasse and cachaza to produce methane. Two rations of bagasse-cachaza

Dasgupta

1983-01-01

117

Anaerobic digestion of the liquid fraction of dairy manure  

SciTech Connect

The authors tested several solid liquid separation systems suitable for processing dairy manure prior to anaerobic digestion. None of the systems tried have completely satisfied the requirements. Evaluated effects of separation on biogas production. Unseparated dairy manure produced more biogas than the liquid fraction.

Haugen, V.; Dahlberg, S.; Lindley, J.A.

1983-06-01

118

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

Microsoft Academic Search

The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production

Rejean Samson; Anh LeDuy

1982-01-01

119

STABILIZATION OF SEWAGE SLUDGE BY TWO-PHASE ANAEROBIC DIGESTION  

EPA Science Inventory

The research described in the report was concerned with evaluation of alternative approaches to anaerobic digestion, a process commonly used on the residual stream from wastewater treatment. The principal approach studied was that of separating the acid- and methane-forming phase...

120

Start-up of anaerobic digestion of sulfate wastewater  

Microsoft Academic Search

During the anaerobic treatment of high sulfate content wastewater, large amounts of sulfide are produced and cause unfavorable conditions. The start-up of such a digestion is often a critical step. This study provides key parameters for a proper start-up. The effect of the sludge and the influence of trace metals were investigated. Using discontinuous cultures, it was shown that an

Gilles Percheron; Nicolas Bernet; René Moletta

1997-01-01

121

Ultrasonically enhanced anaerobic digestion of waste activated sludge  

Microsoft Academic Search

Anaerobic digestion is increasingly applied to stabilise sludge and to reduce operating costs of the wastewater treatment plant by generating biogas, considered as a sustainable energy source. The process suffers from many drawbacks such as slow and incomplete degradation rates, the result of the slow and rate?limiting sludge hydrolysis step, due to the low biodegradability of the cell walls and

Lise Appels; Raf Dewil; Jan Baeyens; Jan Degrève

2008-01-01

122

Anaerobic Digestion. Instructor's Guide. Biological Treatment Process Control.  

ERIC Educational Resources Information Center

|This instructor's guide contains materials needed to teach a four-lesson unit on anaerobic digestion control. These materials include: (1) unit overview; (2) lesson plans; (3) lecture outlines; (4) student worksheets for each lesson (with answers); and (5) two copies of a final quiz (with and without answers). Lesson 1 is a review of the theory…

Carnegie, John W., Ed.

123

A fuzzy logic approach to control anaerobic digestion.  

PubMed

One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the next day, to obtain a high biogas quality and production. The biogas should contain a high methane concentration (over 50%) and a low concentration of components toxic for fuel cells, e.g. hydrogen sulphide, siloxanes, ammonia and mercaptanes. For producing data to test the control tool, four 20 l anaerobic Continuously Stirred Tank Reactors (CSTR) are operated. For controlling two systems were investigated: a pure fuzzy logic system and a hybrid-system which contains a fuzzy based reactor condition calculation and a hierachial neural net in a cascade of optimisation algorithms. PMID:15296166

Domnanovich, A M; Strik, D P; Zani, L; Pfeiffer, B; Karlovits, M; Braun, R; Holubar, P

2003-01-01

124

Anaerobic digestion of crude glycerol: a review  

Microsoft Academic Search

Several researchers have used crude glycerol as a source of substrate for methane production and power generation, which is a way of adding value to this residue that has a high chemical oxygen demand (COD) and is rich in impurities. This review article summarizes recent data and discussions on the use of crude glycerol as substrate and co-substrate for anaerobic

M. B. Viana; A. V. Freitas; R. C. Leitão; G. A. S. Pinto; S. T. Santaella

2012-01-01

125

Biogas Plasticization Coupled Anaerobic Digestion: Continuous Flow Anaerobic Pump Test Results  

Microsoft Academic Search

In this investigation, the Anaerobic Pump (®TAP) and a conventional continuous flow stirred tank reactor (CFSTR) were tested\\u000a side by side to compare performance. TAP integrates anaerobic digestion (AD) with biogas plasticization–disruption cycle to\\u000a improve mass conversion to methane. Both prototypes were fed a “real world” 50:50 mixture of waste-activated sludge (WAS)\\u000a and primary sludge and operated at room temperature

Keith A. Schimel; David R. Boone

2010-01-01

126

An automated spectrophotometric system for monitoring buffer capacity in anaerobic digestion processes  

Microsoft Academic Search

Anaerobic digestion is a suitable method for the treatment of wastewater and organic wastes, yielding biogas as a useful by-product. A common way of preventing instability problems and avoiding acidification in anaerobic digesters is to keep the organic load to the digester far below its maximum capacity. An improved way of operating digesters would be to use monitoring and control

Tor Gunnar Jantsch; Bo Mattiasson

2004-01-01

127

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

ERIC Educational Resources Information Center

|This lesson is the first of a two-part series on anaerobic digestion. Topics discussed include the five basic functions of an anaerobic digester, basic theory of the biological processes involved, basic equipment necessary for digestion, and the products of digestion. The lesson includes an instructor's guide and student workbook. The…

Arasmith, E. E.

128

Optimizing the Logistics of Anaerobic Digestion of Manure  

NASA Astrophysics Data System (ADS)

Electrical power production from the combustion of biogas from anaerobic digestion (AD) of manure is a means of recovering energy from animal waste. We evaluate the lowest cost method of moving material to and from centralized AD plants serving multiple confined feeding operations. Two areas are modeled, Lethbridge County, Alberta, Canada, an area of concentrated beef cattle feedlots, and Red Deer County, Alberta, a mixed-farming area with hog, dairy, chicken and beef cattle farms, and feedlots. We evaluate two types of AD plant: ones that return digestate to the source confined feeding operation for land spreading (current technology), and ones that process digestate to produce solid fertilizer and a dischargeable water stream (technology under development). We evaluate manure and digestate trucking, trucking of manure with return of digestate by pipelines, and pipelining of manure plus digestate. We compare the overall cost of power from these scenarios to farm or feedlot-based AD units. For a centralized AD plant with digestate return for land spreading the most economical transport option for manure plus digestate is by truck for the mixed-farming area and by pipelines for the concentrated feedlot area. For a centralized AD plant with digestate processing, the most economical transport option is trucking of manure for both cases.

Ghafoori, Emad; Flynn, Peter C.

129

Reduced-gas-pressure operation of sludge digesters. Final report  

SciTech Connect

The report describes a laboratory research project that examined the effect of reduced gas pressure, or partial vacuum, operation on anaerobic sludge digesters. The focus of the project was the investigation of bench-scale anaerobic reactors that were operated at 0.5, 0.75, 0.83, and 1 atmosphere headspace pressure and fed daily for four different loading conditions at solids retention times of 15 and 25 days. The reduced headspace reactors generally had a higher level of digester performance, as measured by volatile solids destruction and methane generation, than the control reactor. Cumulative data for the 334-day study indicates that digester operation at 0.75 atmosphere provided near optimum methane production and volatile solids destruction. An engineering evaluation of the existing digesters at the Department of Drainage and Sanitation's Metropolitan Syracuse Wastewater Treatment plant concluded that it would be economical to retrofit the existing digesters to operate under partial vacuum conditions.

Not Available

1989-05-01

130

Combined anaerobic and aerobic digestion for increased solids reduction and nitrogen removal.  

PubMed

A unique sludge digestion system consisting of anaerobic digestion followed by aerobic digestion and then a recycle step where thickened sludge from the aerobic digester was recirculated back to the anaerobic unit was studied to determine the impact on volatile solids (VS) reduction and nitrogen removal. It was found that the combined anaerobic/aerobic/anaerobic (ANA/AER/ANA) system provided 70% VS reduction compared to 50% for conventional mesophilic anaerobic digestion with a 20 day SRT and 62% for combined anaerobic/aerobic (ANA/AER) digestion with a 15 day anaerobic and a 5 day aerobic SRT. Total Kjeldahl nitrogen (TKN) removal for the ANA/AER/ANA system was 70% for sludge wasted from the aerobic unit and 43.7% when wasted from the anaerobic unit. TKN removal was 64.5% for the ANA/AER system. PMID:20801476

Novak, John T; Banjade, Sarita; Murthy, Sudhir N

2010-08-17

131

Electrochemical mineralization of anaerobically digested olive mill wastewater.  

PubMed

A novel approach was developed for the energetic valorisation and treatment of olive mill wastewater (OMW), combining anaerobic digestion and electrochemical oxidation. The electrochemical treatment was proposed as the final step to mineralize the remaining OMW fraction from the anaerobic reactor. The electrooxidation of anaerobically digested OMW was investigated over dimensionally stable anodes (DSAs). RuO(2) based anode was significantly more efficient than IrO(2)-type DSA, mainly for the COD removal. IrO(2) based anode promoted a selective oxidation of phenols and colour removal. For instance, after an electrolysis charge of 10.4 × 10(4) C L(-1), COD removals of 14 and 99%, phenols removals of 91 and 100% and colour removals of 85 and 100% were obtained for IrO(2) and RuO(2) DSAs-type, respectively. The electrochemical post-treatment was effectively performed without using a supporting electrolyte and in the presence of the solids that remained from the anaerobic process. The achievement of the required effluent quality for sewer systems disposal depends on the operating conditions of the anaerobic process. Consequently, special care must be taken with the chloride and nitrogen levels that may surpass the legal discharge limits. The electrochemical oxidation over RuO(2) based DSA is an appropriate second-step treatment for OMW disposal, after the recovery of its energetic potential. PMID:22687524

Gonçalves, M R; Marques, I P; Correia, J P

2012-05-17

132

Large eddy simulation of mechanical mixing in anaerobic digesters.  

PubMed

A comprehensive study of anaerobic digestion requires an advanced turbulence model technique to accurately predict mixing flow patterns because the digestion process that involves mass transfer between anaerobes and their substrates is primarily dependent on detailed information about the fine structure of turbulence in the digesters. This study presents a large eddy simulation (LES) of mechanical agitation of non-Newtonian fluids in anaerobic digesters, in which the sliding mesh method is used to characterize the impeller rotation. The three subgrid scale (SGS) models investigated are: (i) Smagorinsky-Lilly model, (ii) wall-adapting local eddy-viscosity model, and (iii) kinetic energy transport (KET) model. The simulation results show that the three SGS models produce very similar flow fields. A comparison of the simulated and measured axial velocities indicates that the LES profile shapes are in general agreement with the experimental data but they differ markedly in velocity magnitudes. A check of impeller power and flow numbers demonstrates that all the SGS models give excellent predictions, with the KET model performing the best. Moreover, the performance of six Reynolds-averaged Navier-Stokes turbulence models are assessed and compared with the LES results. PMID:22038563

Wu, Binxin

2011-10-28

133

Novel anaerobic digestion process with sludge ozonation for economically feasible power production from biogas.  

PubMed

A novel process scheme was developed to achieve economically feasible energy recovery from anaerobic digestion. The new process scheme employs a hybrid configuration of mesophilic and thermophilic anaerobic digestion with sludge ozonation: the ozonated sludge is first degraded in a thermophilic digester and then further degraded in a mesophilic digester. In small-scale pilot experiments of the new process scheme, degradation of VSS improved by 3.5% over the control (mesophilic-only configuration) with 20% less ozone consumption. Moreover, biogas conversion also improved by 7.1% over the control. Selective enrichment of inorganic compounds during centrifugation produced a dewatered sludge cake with very low water content (59.4%). This low water content in the sludge cake improved its auto-thermal combustion potential during incineration and added to the overall energy savings. We conducted a case study to evaluate power generation from biogas for a municipal wastewater treatment plant with an average dry weather flow of 43,000 m3/d. Electricity production cost was 5.2 ¢/kWh for the advanced process with power generation, which is lower than the current market price of 7.2 ¢/kWh. The new anaerobic digestion scheme with power generation may reduce greenhouse gas emissions by about 1,000 t-CO(2)/year compared with the conventional process without power generation. PMID:21508552

Komatsu, K; Yasui, H; Goel, R; Li, Y Y; Noike, T

2011-01-01

134

Methane production from and beneficiation of anaerobic digestion of aquatic plant material  

SciTech Connect

A process is disclosed for improved CH/sub 4/ production by anaerobic digestion of aquatic plant material, at least a portion or all which was grown in organically polluted water. Mixtures of aquatic plant material whose 1 portion was grown in nonpolluted and a 2nd portion comprising approximately 10 wt.% or more grown in organically polluted water can be used. The liquid effluent from the digester may be advantageously returned to the aquatic plant-growing pond to maintain the desired organic pollution. The process provides for improved CH/sub 4/ production from aquatic plant material which is, by itself, recalcitrant to anaerobic digestion. Thus, 2 digesters were operated under the same conditions, the 1st being fed with water hyacinth grown in nonorganic polluted hardwater of BOD 5 mg/l and hardness of 20 grains/gal. and the 2nd being fed with water hyacinth grown in sewage-polluted water of BOD 20 mg/l. Each digester was operated in a semicontinuous completely mixed anaerobic manner with a culture volume of 5 liters for a detention time of 12 days, a loading of 0.1 lb volatile solid/cubic feet-day, and 35/sup 0/ at pH of 6.8-7.1. The runs were contained for several detention times and exhibited stable performance. CH/sub 4/ yield increased approximately 69% and the gas-production rate increased approximately 82% by using water hyacinth feed grown in sewage-polluted water.

Klass, D.L.; Ghosh, S.

1984-01-03

135

Electrolysis-enhanced anaerobic digestion of wastewater.  

PubMed

This study demonstrates enhanced methane production from wastewater in laboratory-scale anaerobic reactors equipped with electrodes for water electrolysis. The electrodes were installed in the reactor sludge bed and a voltage of 2.8-3.5 V was applied resulting in a continuous supply of oxygen and hydrogen. The oxygen created micro-aerobic conditions, which facilitated hydrolysis of synthetic wastewater and reduced the release of hydrogen sulfide to the biogas. A portion of the hydrogen produced electrolytically escaped to the biogas improving its combustion properties, while another part was converted to methane by hydrogenotrophic methanogens, increasing the net methane production. The presence of oxygen in the biogas was minimized by limiting the applied voltage. At a volumetric energy consumption of 0.2-0.3 Wh/L(R), successful treatment of both low and high strength synthetic wastewaters was demonstrated. Methane production was increased by 10-25% and reactor stability was improved in comparison to a conventional anaerobic reactor. PMID:21435864

Tartakovsky, B; Mehta, P; Bourque, J-S; Guiot, S R

2011-03-23

136

Modeling fatty acid relationships in animal waste anaerobic digesters  

SciTech Connect

Volatile fatty acid (VFA) relationships are important in the anaerobic digestion of animal wastes as they (acetic, propionic and butyric) are direct precursors of methane, either through direct conversion of acetate or through the intermediate formation of hydrogen and carbon dioxide. Thus, they are essential compounds in the biological conversion of heterogenous wastes to useable products. VFA's are also known inhibitors in the biological conversion process if their concentrations are sufficiently high. Thus, VFA's are simultaneously essential for the process and can be toxic agents should they be present in excess quantities. This relationship makes quantifying VFA's in the modeling studies essential to accurately predicting digester failure or success. A highly correlated relationship between the level of acetic acid and/or the propionic to acetic acid ratio in digesters that were successful and in digesters that failed has been shown. These data have been used to calibrate an original comprehensive methanogenesis model and along with the addition of dual-use substrate kinetics for the simultaneous catalysis of propionate and butyrate, have produced a much improved prediction of the VFA relationships observed in operating anaerobic digesters. This manuscript describes the addition of the dual-use substrate kinetics and the modification of the kinetic parameters of the original methanogenic model and compared the simulated output of the original and modified models to demonstrate the improved predictive ability. (Refs. 12).

Hill, D.T.; Bolte, J.P.

1987-01-01

137

Velocity gradient as a tool to characterise the link between mixing and biogas production in anaerobic waste digesters.  

PubMed

Whilst the importance of mixing in anaerobic digesters to enhance process performance and gas production is well recognised, the specific effects of mixing regime on biogas production are not clear. Here, the velocity gradient is used to demonstrate the importance of minimally mixed zones in a digester, with computational fluid dynamics (CFD) models indicating that 20-85% of a laboratory-scale digester experiences local velocity gradients of less than 10 s?¹, dependent on mixing speed. Experimental results indicate that there is a threshold above which increased mixing speed (and hence velocity gradient) becomes counter-productive and biogas production falls. The effects of minimal mixing on digester microbiology are considered with the creation or destruction of localised pockets of high acetate concentration providing a possible explanation for the velocity gradient threshold. The identification of this threshold represents a valuable contribution to the understanding of the effects of mixing on gas production in anaerobic digesters. PMID:23787320

Sindall, R; Bridgeman, J; Carliell-Marquet, C

2013-01-01

138

The effects of digestion temperature and temperature shock on the biogas yields from the mesophilic anaerobic digestion of swine manure  

Microsoft Academic Search

In order to obtain basic design criteria for anaerobic digesters of swine manure, the effects of different digesting temperatures, temperature shocks and feed loads, on the biogas yields and methane content were evaluated. The digester temperatures were set at 25, 30 and 35°C, with four feed loads of 5%, 10%, 20% and 40% (feed volume\\/digester volume). At a temperature of

K. J. Chae; Am Jang; S. K. Yim; In S. Kim

2008-01-01

139

Anaerobic digestion of two biodegradable municipal waste streams.  

PubMed

Landfill avoidance for organic wastes is now a high priority worldwide. Two fractions of the municipal waste stream were considered with respect to their potential for diversion through controlled anaerobic digestion. The physical and chemical properties of source segregated domestic food waste (ss-FW) and of the mechanically-recovered organic fraction of municipal solid waste (mr-OFMSW) were analysed, and their methane yields determined in both batch and semi-continuous digestion. Methane potentials were compared with predicted values based on biochemical composition, elemental analysis and carbon mass balance, and the differences explained by compositional analysis of feedstocks and digestates. The ss-FW had a higher percentage biodegradability and higher energy potential on a dry weight basis due to the high proportion of proteins and fats in this waste, although the energy potential of the mr-OFMSW was slightly higher on a wet weight (WW) basis. The mr-OFMSW showed very stable digestion characteristics, whereas the ss-FW had a high digestate ammoniacal-N concentration and volatile fatty acid accumulation leading to some process instability. Digestates from semi-continuous trials with mr-OFMSW had high concentrations of potentially toxic elements (PTE) and a lower nutrient content than ss-FW digestate, making the former unsuitable for application to land used in food production. PMID:22504715

Zhang, Yue; Banks, Charles J; Heaven, Sonia

2012-04-12

140

Nutrient solubilization and its availability following anaerobic digestion.  

PubMed

This study aims to investigate solubilization of elements (P, N, K, Ca and Mg) during anaerobic digestion (AD) of solid agriculture waste. It is important to maintain particularly phosphorous in the aqueous phase to be able to subsequently recover it in a concentrated form via crystallization. Batch AD was carried out at a mesophilic condition (37 °C) and pH 7.0 ± 0.2 on a variety of piggery and poultry solid waste streams. Less than 10% of the total P, Ca and Mg was in soluble form in the digestate. Most of the N and K remained soluble in the digestate. A bioavailability test (citric acid extraction) showed P, Ca and Mg in the digestate were totally available. Complete solubilization of P, Ca and Mg occurred below a threshold of pH 5.5. This indicates these nutrients were released during digestion, and then either bound to form inorganic compounds or adsorbed on solid surfaces in the digestate. These effects reduce the feasibility of post-digestion recovery of the nutrients via struvite crystallization. Strategies to improve nutrient solubilization and recovery during the AD include addition of complexing chemicals, operation at depressed pH, or otherwise modifying the operating conditions. PMID:23306252

Mehta, Chirag M; Batstone, Damien J

2013-01-01

141

Potential of anaerobic digestion of complex waste (water)  

Microsoft Academic Search

Although they differ greatly in origin complex waste(water)s mainly consist of proteins, lipids, carbohydrates and sometimes lignin in addition. Hydrolysis is the first and generally rate-limiting step in the process of anaerobic digestion of particulate organic substrates. Hydrolysis of particulate polymers can be described by Surface Based Kinetics, but for use in practice the empirical first order relation is advised.

G. Zeeman; W. Sanders

2001-01-01

142

Evolution of microorganisms in thermophilic-dry anaerobic digestion  

Microsoft Academic Search

Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times

B. Montero; J. L. Garcia-Morales; D. Sales; R. Solera

2008-01-01

143

Anaerobic sludge digestion with a biocatalytic additive. [Lactobacillus acidophilus  

Microsoft Academic Search

Aimed at improving the process operating characteristics of anaerobic digestion for sludge stabilization and SNG production, this study evaluates the effects of a lactobacillus additive under normal, variable, and overload conditions. This whey fermentation product of an acid-tolerant strain of L. acidophilus fortified with CoCOâ, (NHâ)âHPOâ, ferrous lactate, and lactic acid provides growth factors, metabolic intermediates, and enzymes needed for

S. Ghosh; M. P. Henry; P. A. Fedde

1982-01-01

144

State indicators for monitoring the anaerobic digestion process  

Microsoft Academic Search

Anaerobic process state indicators were used to monitor a manure digester exposed to different types of disturbances, in order to find the most proper indicator(s) for monitoring the biogas process. Online indicators tested were biogas production, pH, volatile fatty acids (VFA), and dissolved hydrogen. Offline indicators tested were methane and hydrogen content in the biogas. A CSTR reactor with 7.2 L

Kanokwan Boe; Damien John Batstone; Jean-Phillippe Steyer; Irini Angelidaki

2010-01-01

145

STATE OF THE ART OF ANAEROBIC DIGESTION IN ITALY  

Microsoft Academic Search

There are more than 2,000 anaerobic digesters working with animal manure in EU countries, in parti- cular in Germany (more than 1,800), followed by Denmark, Austria, Italy and Sweden. It is estimated that biogas production in EU countries was 2762 ktep (32 million MWh) in 2002; 38% from biogas recupera- ted from MSW landfills. For Italy, in 2002, EurObserv'ER estimates

S. Piccinini

146

Anaerobic Digestion for Mitigation of Biodiesel Production Byproducts  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this document, which was part of a workshop held on anaerobic digestion for mitigation of biodiesel production byproducts. It would be useful for instructors looking to develop their own curriculum on biofuels and biodiesel byproducts. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

2011-04-19

147

Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)  

SciTech Connect

Water hyacinth under conventional high-rate digestion conditions exhibited higher CH4 yields and energy recovery efficiencies when grown in sewage-fed lagoons than when grown in a fresh water pond. Mesophilic digestion provided the highest recovery of feed energy in the product gas as CH4, while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific CH4 production rates. CH4 yields, volatile solids reduction, and energy recovery as CH4 from the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

Klass, D.L.; Ghosh, S.

1980-01-01

148

Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)  

SciTech Connect

Water hyacinth under conventional high-rate digestion conditions exhibited higher methane yields and energy recovery efficiencies when grown in sewage-fed lagoons as compared to the corresponding values obtained with water hyacinth grown in a fresh-water pond. Mesophilic digestion provided the highest feed energy recovered in the product gas as methane while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific methane production rates. Methane yields, volatile solids reduction, and energy recovery as methane for the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

Klass, D.L.; Ghosh, S.

1980-01-01

149

DIGESTER GAS - FUEL CELL - PROJECT  

SciTech Connect

GEW has been operating the first fuel cell in Europe producing heat and electricity from digester gas in an environmentally friendly way. The first 9,000 hours in operation were successfully concluded in August 2001. The fuel cell powered by digester gas was one of the 25 registered ''Worldwide projects'' which NRW presented at the EXPO 2000. In addition to this, it is a key project of the NRW State Initiative on Future Energies. All of the activities planned for the first year of operation were successfully completed: installing and putting the plant into operation, the transition to permanent operation as well as extended monitoring till May 2001.

Dr.-Eng. Dirk Adolph; Dipl.-Eng. Thomas Saure

2002-03-01

150

Anaerobic digestion for treatment of stillage from cellulosic bioethanol production.  

PubMed

Thermophilic anaerobic digestion of stillage from a cellulosic ethanol process that uses sugarcane bagasse as feedstock was investigated. A biochemical methane potential (BMP) of 200ml CH4 at STP (gVS)(-1) was obtained. The whole stillage was separated into two fractions: a fraction retained on 0.5mm screen called residue and a fraction passing through 0.5mm screen called filtrate. About 70% of total methane yield of stillage was produced from the filtrate. The filtrate was anaerobically digested in a 15L semi-continuously fed digester operated for 91days at HRTs of 21 and 14days and organic loading rate (OLR) of 1.85 and 2.39g COD L(-1)d(-1). The methane yield from the stillage from the digester was about 90% of the yield from the BMP assays. The influent soluble COD (sCOD) was reduced from between 35.4 and 38.8g COD (L(-1)) to between 7.5 and 8g COD (L(-1)). PMID:23892147

Tian, Zhuoli; Mohan, Gayathri Ram; Ingram, Lonnie; Pullammanappallil, Pratap

2013-07-04

151

Microbial ecology of solid cellulosic materials during aerobic digestion and anaerobic fermentation  

Microsoft Academic Search

A process for anaerobic digestion of cotton willow dust, pressmud and baggase after a preliminary alkaline aerobic digestion had been developed. The microbial ecologies during the aerobic digestion and anaerobic fermentation of these substrates were investigated, with respect to the isolation, identification and characterization of aerobic microorganisms. The study produced information on the survival of aerobic and facultative bacteria, actinomycetes

Charlene P D'Souza; R. H Balasubramanya

1999-01-01

152

The Effect of Enzyme Addition on Anaerobic Digestion of Jose Tall Wheat Grass  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of the addition of enzyme products containing cellulase, hemicellulase, and Beta-glucosidase to anaerobic digestion systems were studied. Anaerobic digestion tests were performed using batch reactors operated at 35°C. The application of enzyme products in three digestion configurations w...

153

Development of a pilot scale anaerobic digester for biogas production from cow manure and whey mix  

Microsoft Academic Search

This paper presents results from anaerobic digestion of cow manure and whey mix. A pilot scale anaerobic digester, 128l in volume, has been developed, to operate under batch and fed-batch conditions. The versatile and unique characteristics of the instrument allowed testing the methane production directly in the farm. The digester performance was evaluated with two calibration tests, the main for

Elena Comino; Maurizio Rosso; Vincenzo Riggio

2009-01-01

154

Cattle waste treatment and Class A biosolid production using temperature-phased anaerobic digester  

Microsoft Academic Search

The performance of the temperature-phased anaerobic digestion (TPAD) process in the digestion of livestock wastes has never been evaluated, though the process has proven advantages over other high-rate anaerobic digestion processes in the treatment of municipal wastewater sludge. This study investigated the applicability of the TPAD process in the stabilization of dairy cattle manure. For the organic loadings investigated from

S Harikishan; Shihwu Sung

2003-01-01

155

Biogas production potential from switch grass-animal manure mixture using dry anaerobic digestion  

Microsoft Academic Search

Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application without adverse environmental effects. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion (> 15% TS: total solid) has an advantage over wet digestion (<10% TS) because it allows for the use of a smaller volume

H. K. Ahn; M. C. Smith

2008-01-01

156

Biogas production from anaerobic digestion of Spirulina maxima algal biomass  

SciTech Connect

The semimicroscopic blue-green alga Spirulina maxima makes an ideal substrate for anaerobic digestion because it is easy to harvest, it can use carbon dioxide from the atmosphere as its carbon source, and its fermentability is higher than that of other small algae. Digestion experiments demonstrated that S. maxima can serve as the sole nutrient for biogas production and that municipal sewage sludge, when adapted to this new substrate, is very stable. During semicontinuous daily-fed trials under non-optimal conditions at an 0.06 lb volatile solids (VS)/ft/sup 3/ (0.97 kg VS/m/sup 3/) loading rate, 33-day retention time, and 86/sup 0/F (30/sup 0/C) digestion temperature, the daily methane yield was 4.2 CF/lb (0.26 m/sup 3//kg) VS added, which represents 47% of the maximum theoretical yield. Studies on optimizing the process are underway.

Samson, R.; LeDuy, A.

1982-08-01

157

Using volatile fatty acid relationships to predict anaerobic digester failure  

SciTech Connect

During recent years, a number of observations have been made in the literature regarding the level and ratio of certain organic acids and the correlation of these acid relationships with anaerobic digester performance, either complete failure or operation in a stressed state. It is an accepted fact that levels of organic acid are important in digestion for two reasons: (a) organic acids (particularly acetic) are the immediate precursors in the metabolic chain leading to methane formation and (b) if present in high concentration, acids are known to cause stress in the microbial population and can ultimately lead to complete process failure. The recent literature (approximately the last 7 years) was searched for digester performance data and organic acid levels. Seventy observations were used in arriving at a relationship between acetic acid level and propionic to acetic acid ratio and digester failure or success. Methane productivity (L CH4/g VS added) was used as the parameter determining digester performance. A definite trend was recognized that suggests acetic acid levels in excess of 800 mg/L or a propionic to acetic acid ratio greater than 1.4 indicate impending digester failure. A laboratory scale study was then conductd to verify this phenomenon. (Refs. 22).

Hill, D.T.; Cobb, S.A.; Bolte, J.P.

1987-01-01

158

Parameter analysis of the IWA Anaerobic Digestion Model No. 1 for the anaerobic digestion of blackwater with kitchen refuse.  

PubMed

The IWA anaerobic digestion model No.1 (ADM1) had been successfully applied to the lab-scale mesophilic blackwater anaerobic digestion (BWAD) plant for cases of only blackwater (BW) feeding and of BW plus kitchen refuse (KR) feeding. In this paper, the simulation results of BW + KR anaerobic digestion are presented and discussed, followed by the analyses and discussion of the critical and important parameters as well as the performance of ADM1 based on these results. The raw BW can contain up to 30% short chain fatty acids (SCFA) which severely impact the performance of the model. The model proved that the disintegration/hydrolysis rate of BW is around 4.5 d(-1), which is about ten times higher than that of KR (Kdis,KR = 0.5 d(-1)). ADM1 is not sensitive to the distribution ratio among carbohydrates, proteins and lipids. For BWAD the C4 metabolism can be integrated in the uptake of LCFA. The uptake delay phenomenon was observed and cannot be simulated by ADM1, but it is tolerable. No unique KI,NH3,ac is found out for all investigated ammonia concentration ranges. Meanwhile, ADM1 is not sensitive to KLa and kp1 so they can easily be set up. PMID:17037179

Feng, Y; Behrendt, J; Wendland, C; Otterpohl, R

2006-01-01

159

Survey of the Anaerobic Biodegradation Potential of Organic Chemicals in Digesting Sludge  

PubMed Central

The degradation potential of 77 organic chemicals under methanogenic conditions was examined with an anaerobic digesting sludge from the United Kingdom. Degradation was assessed in terms of net total gas (CH4 plus CO2) produced, expressed as a percentage of the theoretical production (ThGP). The compounds tested were selected from various chemical groups and included substituted phenols and benzoates, pesticides, phthalic acid esters, homocyclic and heterocyclic ring compounds, glycols, and monosubstituted benzenes. The results obtained were in good agreement with published surveys of biodegradability in U.S. digesting sludges and other methanogenic environments. In general, the presence of chloro or nitro groups inhibited anaerobic gas production, while carboxyl and hydroxyl groups facilitated biodegradation. The relationship between substituent position and susceptibility to methanogenic degradation was compound dependent. The following chemicals were completely degraded (?80% ThGP) at a concentration of 50 mg of carbon per liter: phenol, 2-aminophenol, 4-cresol, catechol, sodium benzoate, 4-aminobenzoic acid, 3-chlorobenzoic acid, phthalic acid, ethylene glycol, diethylene glycol, triethylene glycol, sodium stearate, and quinoline. 3-Cresol, 4-chlorobenzoic acid, dimethyl phthalate, and pyridine were partially degraded. Although the remaining chemicals tested were either persistent or toxic, their behavior may differ at more environmentally realistic chemical-to-biomass ratios. Our findings suggest that biodegradability assessments made with sludge from one source can be extrapolated to sludge from another source with a reasonable degree of confidence and should help in predicting the fate of an organic chemical during the anaerobic digestion of sewage sludge.

Battersby, Nigel S.; Wilson, Valerie

1989-01-01

160

Generalised modelling approach for anaerobic co-digestion of fermentable substrates.  

PubMed

A general methodology to implement fermentable soluble substrates in the IWA Anaerobic Digestion Model No. 1 (ADM1) that extends its application to anaerobic co-digestion of multiple substrates is presented. The approach considers the fermentation of new soluble substrates, not originally described in ADM1, as channelled through mass- and electron-balanced sugar fermentation equivalent reactions, and that fermentable substrates are degraded by a generic group of fermenters instead of the original ADM1 sugar fermenters. Therefore, no additional microbial group state is required. An additional term that modifies the ADM1 sugar fermentation kinetics equation was included to account for the competition among multiple substrates to be degraded by a particular biomass group. The model was validated at pilot scale treating a blend of pig manure (soluble fraction), wine and gelatine at mesophilic conditions. Only the ADM1 acetoclastic ammonia inhibition parameter was calibrated to obtain consistent model prediction of gas and liquid composition. PMID:24012848

García-Gen, Santiago; Lema, Juan M; Rodríguez, Jorge

2013-08-19

161

Multi-wavelength fluorometry for anaerobic digestion process monitoring.  

PubMed

Applicability of multi-wavelength fluorometry for anaerobic digestion process monitoring was investigated in a 3.5 L upflow anaerobic sludge bed (UASB) lab-scale reactor. Both off-line and on-line monitoring of key process parameters was tested. Off-line emission spectra were measured at an angle of 90 degrees to the excitation beam using a cuvette. On-line measurements were carried out using a fiber optic probe in the external recirculation line of the digester. Fluorescence spectra were correlated to available analytical measurements to obtain partial least square regression models. An independent set of measurements was used to validate the regression models. Model estimations showed reasonable agreement with analytical measurements with multiple determination coefficients (R2) between 0.6 and 0.95. Results showed that offline fluorescence measurements can be used for fast estimation of anaerobic digestor effluent quality. At the same time, the on-line implementation of multi-wavelength fluorescence measurements can be used for realtime process monitoring and, potentially, for on-line process control. PMID:16180465

Morel, E; Santamaria, K; Perrier, M; Guiot, S R; Tartakovsky, B

2005-01-01

162

Treatment of separated piggery anaerobic digestate liquid using woodchip biofilters.  

PubMed

The Irish nitrates directive restricts the land area suitable for landspreading of pig manure, so anaerobic digestion warrants consideration. In this study, six identical Lodgepole pine woodchip biofilters were set up to treat the separated liquid fraction of digestate after anaerobic digestion of pig manure. Two hydraulic loading rates were examined: 5 L/m2/d (LLR) and 10 L/m2/d (HLR). Following a start-up period of 70 days, an average of 90% and 71% of NH4(+)-N was removed at LLR and HLR, respectively. LLR resulted in higher total nitrogen removals than HLR (p < 0.05). Efficient nitrification occurred at LLR as indicated by the lower NH4(+)-N (p < 0.05) and higher NO3(-)-N (p < 0.05) concentrations in the biofilter effluent. A batch experiment testing the capacity of saturated woodchips in removing total oxidized nitrogen (TON) from the effluent of the woodchip biofilters showed that TON was reduced by 323 mg/L from 663 mg/L in 360 h, indicating that the aerobic woodchip biofilters should incorporate a saturated layer ofwoodchips at the base ofthe biofilters to enhance nitrogen removal. PMID:23837316

Carney, K N; Rodgers, M; Lawlor, P G; Zhan, X

163

Psychrophilic anaerobic digestion of guinea pig manure in low-cost tubular digesters at high altitude.  

PubMed

Guinea pig is one of the most common livestock in rural communities of the Andes. The aim of this research was to study the anaerobic digestion of guinea pig manure in low-cost unheated tubular digesters at high altitude. To this end, the performance of two pilot digesters was monitored during 7 months; and two greenhouse designs were compared. In the dome roof digester the temperature and biogas production were significantly higher than in the shed roof digester. However, the biogas production rate was low (0.04 m(biogas)(3)m(digester)(-3) d(-1)), which is attributed to the low organic loading rate (0.6 kg(VS)m(digester)(-3)d(-1)) and temperature (23°C) of the system, among other factors. In a preliminary fertilization study, the potato yield per hectare was increased by 100% using the effluent as biofertilizer. Improving manure management techniques, increasing the organic loading rate and co digesting other substrates may be considered to enhance the process. PMID:21450457

Garfí, Marianna; Ferrer-Martí, Laia; Villegas, Vidal; Ferrer, Ivet

2011-03-29

164

Anaerobic digestion of tannery waste: semi-continuous and anaerobic sequencing batch reactor processes.  

PubMed

Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37 degrees C or 55 degrees C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100 days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55 degrees C is estimated to be 0.617 m(3)kg(-1) of volatile suspended solids for tannery waste sludge, 0.377 m(3)kg(-1) for tannery waste trimmings and 0.649 m(3)kg(-1) for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4 degrees C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55 degrees C. PMID:19699632

Zupancic, Gregor D; Jemec, A

2009-08-21

165

Anaerobic digestion of secondary residuals from an anaerobic bioreactor at a brewery to enhance bioenergy generation.  

PubMed

Many beer breweries use high-rate anaerobic digestion (AD) systems to treat their soluble high-strength wastewater. Biogas from these AD systems is used to offset nonrenewable energy utilization in the brewery. With increasing nonrenewable energy costs, interest has mounted to also digest secondary residuals from the high-rate digester effluent, which consists of yeast cells, bacteria, methanogens, and small (hemi)cellulosic particles. Mesophilic (37 degrees C) and thermophilic (55 degrees C) lab-scale, low-rate continuously-stirred anaerobic digestion (CSAD) bioreactors were operated for 258 days by feeding secondary residuals at a volatile solids (VS) concentration of approximately 40 g l(-1). At a hydraulic retention time (HRT) of 15 days and a VS loading rate of 2.7 g VS l(-1) day(-1), the mesophilic bioreactor showed an average specific volumetric biogas production rate of 0.88 l CH4 l(-1) day(-1) and an effluent VS concentration of 22.2 g VS l(-1) (43.0% VS removal efficiency) while the thermophilic bioreactor displayed similar performances. The overall methane yield for both systems was 0.21 l CH4 g(-1) VS fed and 0.47-0.48 l CH4 g(-1) VS removed. A primary limitation of thermophilic digestion of this protein-rich waste is the inhibition of methanogens due to higher nondissociated (free) ammonia (NH3) concentrations under similar total ammonium (NH4+) concentrations at equilibrium. Since thermophilic AD did not result in advantageous methane production rates or yields, mesophilic AD was, therefore, superior in treating secondary residuals from high-rate AD effluent. An additional digester to convert secondary residuals to methane may increase the total biogas generation at the brewery by 8% compared to just conventional high-rate digestion of brewery wastewater alone. PMID:18188623

Bocher, Benjamin T; Agler, Matthew T; Garcia, Marcelo L; Beers, Allen R; Angenent, Largus T

2008-01-09

166

Feasibility and strategies for anaerobic digestion of solid waste for energy production in Dar es Salaam city, Tanzania  

Microsoft Academic Search

In Tanzania, the most serious solid waste management problem currently is disposal, but since the largest fraction of the waste is organics which are amenable to anaerobic digestion and composting, it makes environmental and economic sense to explore these options. This prompted the conception of the Taka (waste) Gas Project which is meant to utilise organic solid waste from Dar

Stephen E Mbuligwe; Gabriel R Kassenga

2004-01-01

167

Anaerobic digestion of dairy wastewater by inverse fluidization: The inverse fluidized bed and the inverse turbulent bed reactors  

Microsoft Academic Search

This paper describes the application of the inverse fluidization technology to the anaerobic digestion of dairy wastewater. Two reactors were investigated: the inverse fluidized bed reactor and the inverse turbulent reactor. In these reactors, a granular floating solid is expanded by a down?flow current of effluent or an up?flow current of gas, respectively. The carrier particles (Extendospheres) were chosen for

C. Arnaiz; P. Buffiere; S. Elmaleh; J. Lebrato; R. Moletta

2003-01-01

168

Evaluation of an electronic nose for the early detection of organic overload of anaerobic digesters.  

PubMed

This study aimed at analysing the utilization of an electronic nose (e-nose) to serve as a specific monitoring tool for anaerobic digestion process, especially for detecting organic overload. An array of non specific metal oxide semiconductor gas sensors were used to detect process faults due to organic overload events in twelve 1.8-L anaerobic semi-continuous reactors. Three different load strategies were followed: (1) a cautious organic load (1.3 gVS L(-1) day(-1)); (2) an increasing load strategy (1.3-5.3 gVS L(-1) day(-1)) and (3) a cautious organic load with load pulses of up to 12 gVS L(-1) day(-1). A first monitoring campaign was conducted with three different substrates: sucrose, maize oil and a mix of sucrose/oil during 60 days. The second campaign was run with dry sugar beet pulp for 45 days. Hotelling's T(2) value and upper control limit to a reference set of digesters fed with a cautious OLR (1.3 gVS L(-1) day(-1)) was used as indirect state variable of the reactors. Overload situations were identified by the e-nose apparatus with Hotelling's T(2) values at least four times higher in magnitude than the upper control limit of 23.7. These results confirmed that the e-nose technology appeared promising for online detection of process imbalances in the domain of anaerobic digestion. PMID:22644064

Adam, Gilles; Lemaigre, Sébastien; Romain, Anne-Claude; Nicolas, Jacques; Delfosse, Philippe

2012-05-30

169

Biogas plasticization coupled anaerobic digestion: batch test results.  

PubMed

Biogas has unique properties for improving the biodegradability of biomass solids during anaerobic digestion (AD). This report presents batch test results of the first investigation into utilizing biogas plasticization to "condition" organic polymers during active digestion of waste activated sludge (WAS). Preliminary design calculations based on polymer diffusion rate limitation are presented. Analysis of the 20 degrees C batch test data determined the first order (k(1)) COD conversion coefficient to be 0.167 day(-1) with a maximum COD utilization rate of 11.25 g L(-1) day(-1). Comparison of these batch test results to typical conventional AD performance parameters showed orders of magnitude improvement. These results show that biogas plasticization during active AD could greatly improve renewable energy yields from biomass waste materials such as MSW RDF, STP sludges, food wastes, animal manure, green wastes, and agricultural crop residuals. PMID:17054122

Schimel, Keith A

2007-06-01

170

Impact of landfill leachate on anaerobic digestion of sewage sludge.  

PubMed

The feasibility of mesophilic anaerobic co-digestion of landfill leachate and sewage sludge was examined in a bench-scale experiment. Three complete-mix, flow-through digesters were operated in a semi-continuous mode. During both phases of research all digesters received 500 ml d(-1) of raw sludge and Reactor 1 was always the control reactor--fed sludge only. During Phase 1, leachate volumes less than 12% of the sludge volume were fed to Reactors 2 and 3. During Phase 2 larger amounts of leachate were added, exceeding 20% of sludge volume which led to an overall decrease in the hydraulic residence time of the digesters. All reactors achieved stable operation, which indicated that the co-digestion of sewage sludge and landfill leachate is feasible During Phase 1, an increase in the average daily methane production from 2.5 l d(-1) to 3.1 l d(-1) and 3.2 l d(-1) was observed; the biomethanation production (BMP) increased from 0.46 to 0.6 m3 - 0.7 m3 CH4 (kg VS rem.)(-1). The average volatile solids reduction (VSR) increased from 46.1% to 48.6% and 49.0%. In Phase 2, the total methane production in the control reactor was significantly higher, at 4.6 l d(-1), while the addition of larger, by volume, amounts of leachate, decreased the methane production to 4.3 l d(-1) and 4.2 l d(-1), respectively. The average BMP values were 0.8, 0.87, and 0.81 m3 CH4 (kg VS rem.)(-1), respectively. In Phase 2, leachate addition decreased the average VSR from 51% to 49% and 45.6%. After calculating that leachate addition to digesters would not increase heavy metal concentrations in the produced biosolids it was concluded that mesophilic anaerobic co-digestion of sewage sludge and landfill leachate is feasible, and provides a promising alternative to aerobic co-treatment. PMID:12803248

Hombach, S T; Oleszkiewicz, J A; Lagasse, P; Amy, L B; Zaleski, A A; Smyrski, K

2003-05-01

171

Interactive model to assess economics of anaerobic digestion of the farm  

NASA Astrophysics Data System (ADS)

An interactive computer model, to provide economic assessment for on the farm anaerobic digestion systems was designed. The model is accessed as part of the MASEC Models Library. It consists of two phases: engineering analysis and economic analysis. User inputs are stored in a data base and may be retained for future use. Model outputs include a recap of user inputs, calculations for gas production, digester heat requirements, system revenues, yearly cash flow, and a graph of the net present value of the investment. The model is generalized so that nonfarm applications may also be analyzed. The program will work equally well for various digester designs such as continuously stirred reactors, plug flow systems, and fluidized bed columns.

1981-08-01

172

Investigation of Poultry Waste for Anaerobic Digestion: A Case Study  

NASA Astrophysics Data System (ADS)

Anaerobic Digestion (AD) is a biological conversion technology which is being used to produce bioenergy all over the world. This energy is created from biological feedstocks, and can often use waste products from various food and agricultural processors. Biogas from AD can be used as a fuel for heating or for co-generation of electricity and heat and is a renewable substitute to using fossil fuels. Nutrient recycling and waste reduction are additional benefits, creating a final product that can be used as a fertilizer in addition to energy benefits. This project was conducted to investigate the viability of three turkey production wastes as AD feedstock: two turkey litters and a material separated from the turkey processing wastewater using dissolved air flotation (DAF) process. The DAF waste contained greases, oils and other non-commodity portions of the turkey. Using a variety of different process methods, types of bacteria, loading rates and food-to-microorganism ratios, optimal loading rates for the digestion of these three materials were obtained. In addition, the co-digestion of these materials revealed additional energy benefits. In this study, batch digestion tests were carried out to treat these three feedstocks, using mesophilic and thermophilic bacteria, using loading rates of 3 and 6 gVS/L They were tested separately and also as a mixture for co-digestion. The batch reactor used in this study had total and working volumes of 1130 mL and 500 mL, respectively. The initial organic loading was set to be 3 gVS/L, and the food to microorganism ratio was either 0.6 or 1.0 for different treatments based on the characteristics of each material. Only thermophilic (50 +/- 2ºC) temperatures were tested for the litter and DAF wastes in continuous digestion, but mesophilic and thermophilic batch digestion experiments were conducted. The optimum digestion time for all experiments was 14 days. The biogas yields of top litter, mixed litter, and DAF waste under mesophilic batch conditions all at 3 gVS/L loading were determined to be 148.6 +/- 7.82, 176.5 +/- 11.1 and 542.0 +/- 37.9 mL/ gVS, respectively and were 201.9 +/- 10.0, 210.4 +/- 29.3, and 419.3 +/- 12.1 mL/gVS, respectively, for initial loading of 6 gVS/L. Under thermophilic batch conditions, the top litter, mixed litter, and DAF waste had the biogas yields of 255.3 +/- 7.9, 313.4 +/- 30.1and 297.4 +/- 33.8 mL/gVS for loading rate of 3 gVS/L and 233.8 +/- 45.3, 306.5 +/- 11.8 and 185.1 +/- 0.85 mL/gVS for loading rate of 6 gVS/L. The biogas yields from co-digestion of the mixed litter and DAF waste at 3 gVS/L were 461.8 +/- 41.3 mL/gVS under thermophilic conditions. The results from batch anaerobic digestion tests were then used for designing continuous digestion experiments. All the continuous digestion experiments were conducted by using an Anaerobic Phase Solids (APS) digester system operated at a thermophilic temperature. The total volume of the continuous digester system was 4.8 L and the working volume was around 4.4 L. The APS digester system had two hydrolysis reactors and one biogasification reactor. Feedstock was loaded into the hydrolysis reactors in batches. The feedstock digestion time was 14 days and the average organic loading rate (OLR) of the system was 3 gVS/L/day. The experiment has three distinct feedstock stages, first with turkey litter waste, a co-digestion of DAF and turkey litter waste, followed by DAF waste. The biogas yields were determined to be 305.2 +/- 70.6 mL/gVS/d for turkey mixed litter, 455.8 +/- 77.2 mL/gVS/d during the mixture of mixed litter and DAF waste, and 382.0 +/- 39.6 mL/gVS for DAF waste. The biogas yields from the thermophilic batch test yields compare with that of the continuous digester yields. For experiments utilizing turkey litter, batch tests yielded 313.4 +/- 30.1mL/gVS biogas and 305.2 +/- 70.6 mL/gVS/d for continuous experiments. For experiments using codigestion of turkey litter and DAF waste, batches yielded 461.8 +/- 41.3 mL/gVS biogas comparing well to continuous digester operation that yielded 455.8 +/- 77.

Salam, Christopher R.

173

The role of anaerobic sludge recycle in improving anaerobic digester performance.  

PubMed

Solids retention time (SRT) is a critical parameter for the performance of anaerobic digesters (AD) in wastewater treatment plants. AD SRT should increase when active biomass is input to the AD by recycling anaerobic sludge via the wastewater-treatment tanks, creating a hybrid aerobic/anaerobic system. When 85% of the flow through the AD was recycled in pilot-scale hybrid systems, the AD SRT increased by as much as 9-fold, compared to a parallel system without anaerobic-sludge recycle. Longer AD SRTs resulted in increased hydrolysis and methanogenesis in the AD: net solids yield decreased by 39-96% for overall and 23-94% in the AD alone, and AD methane yield increased 1.5- to 5.5-fold. Microbial community assays demonstrated higher, more consistent Archaea concentrations in all tanks in the wastewater-treatment system with anaerobic-sludge recycle. Thus, multiple lines of evidence support that AD-sludge recycle increased AD SRT, solids hydrolysis, and methane generation. PMID:23265819

Young, Michelle N; Krajmalnik-Brown, Rosa; Liu, Wenjun; Doyle, Michael L; Rittmann, Bruce E

2012-11-28

174

Controlled struvite crystallisation for removing phosphorus from anaerobic digester sidestreams.  

PubMed

Enhanced biological phosphorus removal wastewater treatment plants that use anaerobic digesters for sludge treatment, have high phosphorus concentrations in the sidestreams from their sludge dewatering equipment. To remove phosphorus from such sidestreams controlled struvite crystallisation can be used. Struvite (or MAP) is a naturally occurring crystal of magnesium, ammonium and phosphate. We present operational results obtained with a continuously operated pilot-scale MAP reactor. The pilot-scale reactor (143 l) was an air agitated column reactor with a reaction and a settling zone, based on the Phosnix process of Unitika Ltd., Japan. The influent to the MAP reactor was centrate from the centrifuge that dewaters anaerobically digested sludge at the Oxley Creek wastewater treatment plant in Brisbane. We used a 60% magnesium hydroxide slurry to add the required magnesium to the process and to obtain the alkaline pH value required. The pilot-scale MAP process achieved an ortho-P removal ratio of 94% from an average influent ortho-P concentration of 61 mg/l. The reactor was operated at a pH of around 8.5. Insufficient dosing of magnesium reduced the P removal performance. There was no influence of the hydraulic residence time on the process in the range of 1-8 h. The dry MAP product had cadmium, lead and mercury concentrations well below the legal limits for fertilisers in Queensland, Australia and can be reused as a valuable slow-release fertiliser. PMID:11257869

Münch, E V; Barr, K

2001-01-01

175

State estimation for anaerobic digesters using the ADM1.  

PubMed

The optimization of full-scale biogas plant operation is of great importance to make biomass a competitive source of renewable energy. The implementation of innovative control and optimization algorithms, such as Nonlinear Model Predictive Control, requires an online estimation of operating states of biogas plants. This state estimation allows for optimal control and operating decisions according to the actual state of a plant. In this paper such a state estimator is developed using a calibrated simulation model of a full-scale biogas plant, which is based on the Anaerobic Digestion Model No.1. The use of advanced pattern recognition methods shows that model states can be predicted from basic online measurements such as biogas production, CH4 and CO2 content in the biogas, pH value and substrate feed volume of known substrates. The machine learning methods used are trained and evaluated using synthetic data created with the biogas plant model simulating over a wide range of possible plant operating regions. Results show that the operating state vector of the modelled anaerobic digestion process can be predicted with an overall accuracy of about 90%. This facilitates the application of state-based optimization and control algorithms on full-scale biogas plants and therefore fosters the production of eco-friendly energy from biomass. PMID:22797239

Gaida, D; Wolf, C; Meyer, C; Stuhlsatz, A; Lippel, J; Bäck, T; Bongards, M; McLoone, S

2012-01-01

176

Thermochemical Pretreatment for Anaerobic Digestion of Sorted Waste  

NASA Astrophysics Data System (ADS)

The effect of alkaline hydrothermal pre-treatment for anaerobic digestion of mechanically-sorted municipal solid waste (MSW) and source-sorted waste was studied. Waste was hydrothermally pre-treated in dilute alkali solution. Hydrolysis product was incubated in 500 ml saline bottle to determine methane potential (MP) under mesospheric anaerobic conditions. Optimum reaction condition obtained in the study is 170 °C at the dose of 4 g NaOH/100 g solid for one hour. Soluble COD was 13936 mg/L and methane yield was 164 ml/g VS for 6 days incubation at optimum conditions. More than 50% biogas increase was achieved over the control, and methane conversion ratio on carbon basis was enhanced to 30.6%. The digestion period was less than 6 days when pre-treatment temperature was above 130 °C. The organic part of sorted waste is mainly constituted of kitchen garbage and leaf. Model kitchen garbage was completely liquidized at 130 °C for one hour and the methane yield was 276 ml/g VS. Addition of alkali enhance hydroxylation rate and methane yield slightly. The biogas potential of leaf could be observed by pre-treatment above 150 °C under alkaline condition.

Hao, W.; Hongtao, W.

2008-02-01

177

Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Semi-annual report  

SciTech Connect

Anaerobic digestion of municipal waste has been demonstrated to be feasible in bench scale experiments by Pfeffer (1974). Approximately, 50% reduction in mass and production of 6000 ft/sup 3/ of gas/ton have been estimated. The gas composition is estimated to be 50% methane and 50% carbon monoxide. The technical and economic feasibility of anaerobic digestion with an ultimate objective of commercialization are discussed. A plant has been built at Pompano Beach, Florida on an existing shredding and landfill operation site. The plant design capacity is 100 tons/day. Two digesters have been constructed to be used in parallel. The process consists of primary shredding, metal separation, secondary shredding, air classification and digestion of light fraction. Sewage sludge was used to seed the initial mixture in the digester. The output slurry is vacuum filtered and the filter cake disposed on an existing landfill. The filtrate is recycled. Excess filtrate is sprayed on the landfill. At present the output gas is being flared. A flow chart for the plant is presented. It is imperative that environmental investigations be conducted on new energy technology prior to commercialization. A project was initiated to characterize all input and output streams and to assess the potential for ground water contamination by landfill disposal of effluents. Detailed chemical, biological and physical characterization efforts supported by leaching and modelling studies are being conducted to achieve the stated objectives. Some mutagenic studies were also conducted. The environmental investigations were started in August 1978. Sengupta et al (1979a) reported the first year's efforts.

Sengupta, S.; Farooq, S.; Gerrish, H.P.; Wong, K.F.; Daly, E.L. Jr.; Chriswell, C.

1980-02-01

178

Biogas generation potential by anaerobic digestion for sustainable energy development in India  

Microsoft Academic Search

The potential of biogas generation from anaerobic digestion of different waste biomass in India has been studied. Renewable energy from biomass is one of the most efficient and effective options among the various other alternative sources of energy currently available. The anaerobic digestion of biomass requires less capital investment and per unit production cost as compared to other renewable energy

P. Venkateswara Rao; Saroj S. Baral; Ranjan Dey; Srikanth Mutnuri

2010-01-01

179

Evaluation of biogas production by dry anaerobic digestion of switchgrass-animal manure mixtures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application without adverse environmental effects. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion (> 15% TS; total solid) has an advantage ov...

180

Speciation modeling of ammonia and other major solutes in anaerobic digesters  

Technology Transfer Automated Retrieval System (TEKTRAN)

Anaerobic digestion of high-nitrogen wastes can be inhibited by high concentrations of un-ionized ammonia, NH**3 (aq). Understanding the toxicity of NH**3 (aq) to anaerobic digestion requires an understanding of the mechanisms controlling its concentration. Previous work on ammonia toxicity in an...

181

Development of an advanced anaerobic digester design and a kinetic model for biogasification of water hyacinth/sludge blends  

SciTech Connect

The Institute of Gas Technology (IGT) conducted a comprehensive laboratory-scale research program to develop and optimize the anaerobic digestion process for producing methane from water hyacinth and sludge blends. This study focused on digester design and operating techniques, which gave improved methane yields and production rates over those observed using conventional digesters. The final digester concept and the operating experience was utilized to design and operate a large-scale experimentla test unit (ETU) at Walt Disney World, Florida. This paper describes the novel digester design, operating techniques, and the results obtained in the laboratory. The paper also discusses a kinetic model which predicts methane yield, methane production rate, and digester effluent solids as a function of retention time. This model was successfully utilized to predict the performance of the ETU. 15 refs., 6 figs., 6 tabs.

Srivastava, V.; Fannin, K.F.; Biljetina, R.; Chynoweth, D.P.; Hayes, T.D.

1986-07-01

182

Impact of food industrial waste on anaerobic co-digestion of sewage sludge and pig manure  

Microsoft Academic Search

The performance of an anaerobic digestion process is much dependent on the type and the composition of the material to be digested. The effects on the degradation process of co-digesting different types of waste were examined in two laboratory-scale studies. In the first investigation, sewage sludge was co-digested with industrial waste from potato processing. The co-digestion resulted in a low

M Murto; L Björnsson; B Mattiasson

2004-01-01

183

Solid-state anaerobic digestion of unsorted municipal solid waste in a pilot-plant scale digester  

Microsoft Academic Search

An anaerobic digestion of municipal solid waste (MSW) was carried out in a pilot-scale reactor to study anaerobic fermentation as it happens in a sanitary landfill. The reactor was not inoculated and the MSW used was taken from the COGERSA landfill site in Asturias, Spain. The experiments were performed in an opaque PVC reactor at 36 ± 1 °C. Water

J. Rodriguez-Iglesias; L. Castrillón; E. Marañón; H. Sastre

1998-01-01

184

Single-stage, batch, leach-bed, thermophilic anaerobic digestion of spent sugar beet pulp  

Microsoft Academic Search

Spent sugar beet pulp as received was digested in a single-stage, batch, unmixed, leach-bed, laboratory scale thermophilic anaerobic digester. Biogasification of each 0.450kg (wet weight) batch of spent pulp was initiated by inoculating with anaerobically digested liquor from previous run. The average methane yield was 0.336m3 CH4 at STP (kgVS)?1, the maximum methane production rate was 0.087m3 CH4 at STP

Abhay Koppar; Pratap Pullammanappallil

2008-01-01

185

Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Semi-annual report  

SciTech Connect

This report summarizes the results of routine monitoring of gas quality, airborne particulates, and solid and liquid phases of the Refcom facility at Pompano Beach, Florida. The plant produces methane from municipal wastes by anaerobic digestion. Bacteriological analysis of residual liquids and process streams were performed. Leaching studies with selected soils, filtrates and bottom layer muck were also conducted. A two-dimensional time model was developed. The first appendix contains the results of trace organic analysis of effluents from the facility. The results of environental studies on methane production are presented in the second appendix. The third appendix describes the gas analysis procedure and the gas composition of gas produced at the facility.

Sengupta, S.; Wong, K.F.V.; Gerrish, H.P.; Nemerow, N.; Daly, E.L. Jr.; Chriswell, C.

1981-02-01

186

Do two-phase biogas plants separate anaerobic digestion phases? - a mathematical model for the distribution of anaerobic digestion phases among reactor stages.  

PubMed

In this article a mathematical model is introduced, which estimates the distribution of the four anaerobic digestion phases (hydrolysis, acidogenesis, acetogenesis and methanogenesis) that occur among the leach bed reactor and the anaerobic filter of a biogas plant. It is shown that only the hydrolysis takes place in the first stage (leach bed reactor), while all other anaerobic digestion phases take place in both reactor stages. It turns out that, besides the usually measured raw materials of the acetogenesis and the methanogenesis phases (organic acids), it is also necessary to analyze the process liquid for raw materials of the acidogenesis phase, i.e., sugars, fatty acids, amino acids, etc. The introduced model can be used to monitor the inhibition of the anaerobic digestion phases in reactor stages and can, thus, help to improve the control system of biogas plants. PMID:23290872

Muha, Ivo; Zielonka, Simon; Lemmer, Andreas; Schönberg, Mandy; Linke, Bernd; Grillo, Alfio; Wittum, Gabriel

2012-12-14

187

Data summary of municipal solid waste management alternatives. Volume 10, Appendix H: Anaerobic digestion of MSW  

SciTech Connect

While municipal solid waste (MSW) thermoconversion and recycling technologies have been described in Appendices A through E, this appendix addresses the role of bioconversion technologies in handling the organic fraction in MSW and sewage sludge. Much of the organic matter in MSW, consisting mainly of paper, food waste, and yard waste, has potential for conversion, along with sewage sludge, through biochemical processes to methane and carbon dioxide providing a measurable, renewable energy resource potential. The gas produced may be treated for removal of carbon dioxide and water, leaving pipeline quality gas. The process also has the potential for producing a stabilized solid product that may be suitable as a fuel for combustion or used as a compost fertilizer. Anaerobic digestion can occur naturally in an uncontrolled environment such as a landfill, or it can occur in a controlled environment such as a confined vessel. Landfill gas production is discussed in Appendix F. This appendix provides information on the anaerobic digestion process as it has been applied to produce methane from the organic fraction of MSW in enclosed, controlled reactors.

Not Available

1992-10-01

188

Anaerobic digestion of wheat straw - Performance of continuous solid-state digestion.  

PubMed

In this study the upflow anaerobic solid-state (UASS) reactor was operated at various conditions to optimize the process parameters for anaerobically digesting wheat straw in a continuous process. Additionally, particle size effects have been studied in the operation at 55 and 60°C. Moreover, the incremental effect of the organic loading rate (OLR) to the system was examined from 2.5 to 8gVSL(-1)d(-1). It was found that the UASS operating at 60°C with a small OLR yields highest methane production, but the advantage over thermophilic operation is negligible. The rise in OLR reduces the systems yields, as expected. From OLR=8gVSL(-1)d(-1) a second stage is necessary to circumvent volatile fatty acids accumulation. PMID:23954246

Pohl, Marcel; Heeg, Kathrin; Mumme, Jan

2013-07-27

189

Survey of the anaerobic biodegradation potential of organic chemicals in digesting sludge.  

PubMed

The degradation potential of 77 organic chemicals under methanogenic conditions was examined with an anaerobic digesting sludge from the United Kingdom. Degradation was assessed in terms of net total gas (CH(4) plus CO(2)) produced, expressed as a percentage of the theoretical production (ThGP). The compounds tested were selected from various chemical groups and included substituted phenols and benzoates, pesticides, phthalic acid esters, homocyclic and heterocyclic ring compounds, glycols, and monosubstituted benzenes. The results obtained were in good agreement with published surveys of biodegradability in U.S. digesting sludges and other methanogenic environments. In general, the presence of chloro or nitro groups inhibited anaerobic gas production, while carboxyl and hydroxyl groups facilitated biodegradation. The relationship between substituent position and susceptibility to methanogenic degradation was compound dependent. The following chemicals were completely degraded (>/=80% ThGP) at a concentration of 50 mg of carbon per liter: phenol, 2-aminophenol, 4-cresol, catechol, sodium benzoate, 4-aminobenzoic acid, 3-chlorobenzoic acid, phthalic acid, ethylene glycol, diethylene glycol, triethylene glycol, sodium stearate, and quinoline. 3-Cresol, 4-chlorobenzoic acid, dimethyl phthalate, and pyridine were partially degraded. Although the remaining chemicals tested were either persistent or toxic, their behavior may differ at more environmentally realistic chemical-to-biomass ratios. Our findings suggest that biodegradability assessments made with sludge from one source can be extrapolated to sludge from another source with a reasonable degree of confidence and should help in predicting the fate of an organic chemical during the anaerobic digestion of sewage sludge. PMID:16347851

Battersby, N S; Wilson, V

1989-02-01

190

Biomass production, anaerobic digestion, and nutrient recycling of small benthic or floating seaweeds  

SciTech Connect

A number of experiments have been carried out supporting the development of a seaweed-based ocean energy farm. Beginning in 1976, forty-two species of seaweed indigenous to the coastal waters of Central Florida were screened for high biomass yields in intensive culture. Gracilaria tikvahiae achieved the highest annual yield of 34.8 g dry wt/m/sup 2/ day. Yield has been found to vary inversely with seawater exchange rate, apparently because of carbon dioxide limitation at low exchange rates. Gracilaria was anaerobically digested in 120 liter and 2 liter reactors. Gas yields in the large digesters averaged 0.4 1/g volatile solids (.24 1 CH/sub 4//gv.s.) with a bioconversion efficiency of 48%. Studies of the suitability of digester residue as a nutrient source for growing Gracilaria have been conducted. Nitrogen recycling efficiency from harvested plant through liquid digestion residue to harvested plant approached 75%. Studies of nutrient uptake and storage by Gracilaria, Ascophyllum, and Sargassum showed that nutrient starved plants are capable of rapidly assimilating and storing inorganic nutrients which may be used later for growth when no nutrients are present in the medium. A shallow water seaweed farm was proposed which would produce methane from harvested seaweed and use digester residues as a concentrated source of nutrients for periodic fertilizations.

Ryther, J.H.

1982-02-01

191

Electron beam pretreatment of sewage sludge before anaerobic digestion.  

PubMed

The pretreatment of waste-activated sludge (WAS) by electron beam irradiation was studied in order to improve anaerobic sludge digestion. The irradiation dose of the electron beam was varied from 0.5 to 10 kGy. Batch and continuous-flow stirred tank reactors (CFSTRs) were operated to evaluate the effect of the electron beam pretreatment on anaerobic sludge digestion. Approximately 30-52% of the total chemical oxygen demand (COD) content of the WAS was solubilized within 24 h after electron beam irradiation. A large quantity of soluble COD, protein, and carbohydrates leached out from cell ruptures caused by the electron beam irradiation. Volatile fatty acids production from the irradiated sludge was approx 90% higher than that of the unirradiated sludge. The degradation of irradiated sewage sludge was described by two distinct first-order decay rates (k1 and k2). Most initial decay reaction accelerated within 10 d, with an average k1 of 0.06/d for sewage sludge irradiated at all dosages. The mean values for the long-term batch first-order decay coefficient (k2) were 0.025/d for irradiated sewage sludge and 0.007/d for unirradiated sludge. Volatile solids removal efficiency of the control reactor fed with unirradiated sewage sludge at a hydraulic retention time (HRT) of 20 d was almost the same as that of the CFSTRs fed with irradiated sludge at an HRT of 10 d. Therefore, disintegration of sewage sludge cells using electron beam pretreatment could reduce the reactor solid retention time by half. PMID:12794296

Shin, Kyung-Sook; Kang, Ho

192

Investigation of Non-Newtonian Flow in Anaerobic Digesters  

NASA Astrophysics Data System (ADS)

This thesis examines how the non-Newtonian characteristics of liquid hog manure affect the flow conditions within a steady-flow anaerobic digester. There are three main parts to this thesis. In the first part of this thesis, the physical properties of liquid hog manure and their variation with temperature and solids concentration are experimentally determined. Naturally-settled manure sampled from an outdoor storage lagoon is studied, and density, viscosity, and particle size distribution are measured. Hog manure with total solids concentrations of less than 3.6% exhibits Newtonian behaviour; manure between 3.6% and 6.5% total solids is pseudoplastic, and fits the power law; manure with more than 6.5% total solids exhibits non-Newtonian and time-dependent characteristics. The second part of this thesis investigates the flow of Newtonian and non-Newtonian fluids---represented by tap water and xanthan gum solution, respectively---within four lab-scale reactor geometries, using residence time distribution (RTD) experiments. The effect of reactor geometry, flow rate, and fluid viscosity are evaluated. In the third part of this thesis, flow conditions within lab-scale and pilot-scale anaerobic digester reactors are simulated using three-dimensional modeling techniques. The RTDs of lab-scale reactors as predicted by the 3D numerical models compare well to the experimental results. The 3D models are also validated using data from particle image velocimetry (PIV) experiments. Finally, the viscous properties of liquid hog manure at 3% and 8% total solids are incorporated into the models, and the results are evaluated.

Langner, Jeremy M.

193

Fermentative hydrogen production from tofu-processing waste and anaerobic digester sludge using microbial consortium.  

PubMed

The combination of tofu-processing waste and anaerobic digester sludge was studied for its fermentative H(2) production capacity in batch and continuous modes using a thermophilic mixed culture. Heat-treatment (110 degrees C, 30 min) in the presence of 0.5% HCl increased the soluble carbohydrate content of the tofu waste from 2.2 to 10.4 g/l. Anaerobic digester sludge was added to the tofu waste for supplementary nutrients with the optimal mixing ratio of 20% (v/v) under batch conditions. In continuous experiments, the effects of HRT(hydraulic retention time) and pH were investigated for the ranges of 2-6h and 5.0-6.0, respectively. The maximal H(2) production rate (12.0 l H(2)/l/day) and yield (2.3 mol H(2)/mol glucose equivalent) were obtained at HRT 4h and pH 5.5 while maintaining the head space gas at 50-60% (v/v) of H(2) without CH(4). This study indicates that the combination of tofu-processing waste and digester sludge can be considered to be one of the most promising forms of organic waste for continuous H(2) production. PMID:19394818

Kim, Mi-Sun; Lee, Dong-Yeol

2009-04-25

194

Comparison of non-agitated and agitated batch, thermophilic anaerobic digestion of sugarbeet tailings.  

PubMed

Sugar beet tailings were anaerobically digested at non-agitated and agitated conditions in identical thermophilic batch reactors. The average methane yield in the agitated digester was only 74% of that in the non-agitated digester. Ninety percent of the ultimate methane yield was produced in approximately 5 days in the non-agitated digester whereas it took 12 days in agitated digester. Even upon using an active inoculum from non-agitated digester the methane rate and yield was low in the agitated digester. On the other hand when the poorly performing inoculum from the agitated digester was transferred to the non-agitated digester, its activity was immediately enhanced. The non-agitated digester harbored a diverse microbial community with phylotypes Methanoculleus and Methanosarcina being dominant methanogens. Methanosaeta was the only methanogen detected in the agitated digester. It also contained a hydrogen-producing bacterial phylotype Petrotoga in high proportion which was not detected in the other digester. PMID:23262019

Tian, Zhuoli; Chauliac, Diane; Pullammanappallil, Pratap

2012-11-24

195

A distributed model of solid waste anaerobic digestion: sensitivity analysis.  

PubMed

A distributed model of anaerobic digestion of solid waste was developed to describe the balance between the rates of polymer hydrolysis and methanogenesis during the anaerobic conversion of rich and lean wastes in batch and continuous-flow reactors. Waste, volatile fatty acids (VFAs), methanogenic biomass and sodium concentrations are the model variables. Diffusion and advection of VFAs inhibiting both polymer hydrolysis and methanogenesis were considered. A sensitivity analysis by changing the key model parameter values was carried out. The model simulations showed that the effective distance between the areas of hydrolysis/acidogenesis and methanogenesis is very important. An initial spatial separation of rich waste and inoculum enhances the methane production and waste degradation at high waste loading if relatively low VFA diffusion into the methanogenic area is taking place. When both hydrolysis and methanogenesis are strongly inhibited by high levels of VFA, fluctuations in biomass concentration are thought to be responsible for initiating the expansion of methanogenic area over the reactor space. PMID:14531433

Vavilin, V A; Rytov, S V; Pavlostathis, S G; Jokela, J; Rintala, J

2003-01-01

196

Enhancement of the conventional anaerobic digestion of sludge: comparison of four different strategies.  

PubMed

Anaerobic digestion (AD) is the preferred option to stabilize sludge. However, the rate limiting step of solids hydrolysis makes it worth modifing the conventional mesophilic AD in order to increase the performance of the digester. The main strategies are to introduce a hydrolysis pre-treatment, or to modify the digestion temperature. Among the different pre-treatment alternatives, the thermal hydrolysis (TH) at 170 degrees C for 30 min, and the ultrasounds pre-treatment (US) at 30 kJ/kg TS were selected for the research, while for the non-conventional anaerobic digestion, the thermophilic (TAD) and the two-stage temperature phased AD (TPAD) were considered. Four pilot plants were operated, with the same configuration and size of anaerobic digester (200 L, continuously fed). The biogas results show a general increase compared to the conventional digestion, being the highest production per unit of digester for the process combining the thermal pre-treatment and AD (1.4 L biogas/L digester day compared to the value of 0.26 obtained in conventional digesters). The dewaterability of the digestate became enhanced for processes TH + AD and TPAD when compared with the conventional digestate, while it became worse for processes US + AD and TAD. In all the research lines, the viscosity in the digester was smaller compared to the conventional (which is a key factor for process performance and economics), and both thermal pre-treatment and thermophilic digestion (TAD and TPAD) assure a pathogen free digestate. PMID:22097010

Pérez-Elvira, S I; Fdz-Polanco, M; Fdz-Polanco, F

2011-01-01

197

CFD simulation of mixing for high-solids anaerobic digestion.  

PubMed

A computational fluid dynamics (CFD) model that simulates mechanical mixing for high-solids anaerobic digestion was developed. Numerical simulations of mixing manure slurry which exhibits non-Newtonian pseudo-plastic fluid behavior were performed for six designs: (i) one helical ribbon impeller; (ii) one anchor impeller; (iii) one curtain-type impeller; (iv) three counterflow (CF-2) impellers; (v) two modified high solidity (MHS 3/39°) impellers; and (vi) two pitched blade turbine impellers. The CFD model was validated against measurements for mixing a Herschel-Bulkley fluid by ribbon and anchor impellers. Based on mixing time with respect to mixing energy level, three impeller types (ribbon, CF-2, and MHS 3/39°) stand out when agitating highly viscous fluids, of these mixing with two MHS 3/39° impellers requires the lowest power input to homogenize the manure slurry. A comparison of digestion material demonstrates that the mixing energy varies with manure type and total solids concentration to obtain a given mixing time. Moreover, an in-depth discussion about the CFD strategy, the influences of flow regime and impeller type on mixing characteristics, and the intrinsic relation between mixing and flow field is included. PMID:22422446

Wu, Binxin

2012-03-16

198

The survival of multidrug-resistant bacteria in thermophilic and mesophilic anaerobic co-digestion of dairy manure and waste milk.  

PubMed

Anaerobic digestion is considered as a promising method to manage animal waste with antibiotic-resistant bacteria. Current research was conducted to investigate the survival of multidrug-resistant bacteria (MDRB) resistant to three groups of antibiotics: (i) cefazolin, neomycin, vancomycin, kanamycin (group 1); (ii) penicillin, oxytetracycline, ampicillin, streptomycin (group 2); and (iii) cefazolin, neomycin, vancomycin, kanamycin, penicillin, oxytetracycline, ampicillin, streptomycin (group 3), in anaerobic digestion of dairy manure and co-digestion of dairy manure and waste milk at 37°C and 55°C for 22 days, respectively. The population densities of three groups of MDRB on peptone, tryptone, yeast and glucose agar plates incubated at 30°C for 7 days before and after digestion showed 100% destruction in both digestates at thermophilic temperature. Overall reduction of more than 90% of three groups of MDRB was observed in mesophilic digestion with no significant differences (P?>?0.05) between manure and milk mixture. Co-digestion of dairy manure and waste milk always produced significantly (P?gas and methane gas than digestion of manure alone at both temperatures. Gas production in each case was significantly (P?digestion than in mesophilic digestion. The results demonstrate that thermophilic co-digestion of dairy manure and waste milk offers more benefits in terms of the environment and economy. PMID:23607603

Beneragama, Nilmini; Iwasaki, Masahiro; Lateef, Suraju A; Yamashiro, Takaki; Ihara, Ikko; Umetsu, Kazutaka

2012-12-17

199

Ozone pre-treatment as improver of PAH removal during anaerobic digestion of urban sludge.  

PubMed

Polycyclic aromatic hydrocarbons are ubiquitous persistent pollutants. They may accumulate in sludge during wastewater treatment because of their low biodegradability and their hydrophobic characteristics. Combination of ozonation and anaerobic digestion may be efficient to remove PAHs naturally present in sludge. The objective of this study was to investigate the impact of ozone pre-treatment, with and without surfactant addition, on the anaerobic degradation of 12 PAHs (from low to high molecular weight). Under anaerobic digestion without ozonation pre-treatment, the highest removals were obtained for the lightest PAHs (3-aromatic rings). Ozonation pre-treatment of sludge allowed to increase biodegradability or bioavailability of each PAH, and the PAH removals were well correlated to the PAH solubility. Finally, addition of tyloxapol before sludge ozone pre-treatment had antagonist effects on PAH removal during anaerobic digestion: negative impact on anaerobic ecosystem activity and improvement of PAH bioaccessibility (particularly the PAHs with the highest octanol water partition coefficients). PMID:17382369

Bernal-Martinez, Arodi; Carrère, Hélène; Patureau, Dominique; Delgenès, Jean-Philippe

2007-03-26

200

PLFA profiles for microbial community monitoring in anaerobic digestion.  

PubMed

The use of municipal solid waste as feedstock for biogas production offers an interesting possibility for waste treatment with the beneficial effect of gaining a green energy source. The involved processes are very complex, and many different organisms connected via a dynamic food web are associated with them. These complex interactions within these microbial communities are still not clearly understood. Therefore, a phospholipid fatty acid (PLFA) profile analysis method, well established in aerobic but still not as common in anaerobic systems, was used to throw some light on this matter. In the present investigation, a 750 m³ biogas reactor (Roppen, Austria) was monitored over a half-year period. During this period, four different phases in terms of gas production could be determined: low (I), increasing (II), high (III), and decreasing (IV) gas production. In combination with the PLFA profiles, we were able to identify changes in the microbial community associated with these phases. PMID:22491989

Schwarzenauer, Thomas; Illmer, Paul

2012-04-11

201

Development of surrogate refuse feedstocks for use in anaerobic digestion studies.  

National Technical Information Service (NTIS)

This report discusses the development of a standard surrogate waste material for use in laboratory scale experiments on the anaerobic digestion of municipal solid waste. The purpose of the standard surrogate waste material is to provide a consistent and r...

P. A. Wheeler

1993-01-01

202

The Effects of Alum Sludge on Primary Sedimentation and Anaerobic Digestion.  

National Technical Information Service (NTIS)

A study investigating the feasibility of disposing alum sludge to sanitary sewers is reported. Since primary clarification and anaerobic digestion are the two sewage treatment processes most likely to be affected by alum sludge disposal, their physical an...

B. A. Rindt

1973-01-01

203

Application of Kaolin for Control of Heavy Metals in Anaerobic Sludge Digestion.  

National Technical Information Service (NTIS)

Six laboratory-scale anaerobic digesters were used to evaluate the potential of kaolin addition for the control of heavy metal toxicity. Adsorption isotherms were obtained for the kaolin-metal system in solutions of the individual metals, nickel, copper, ...

W. H. Cross P. M. Rossello

1983-01-01

204

Anaerobic digestion of wood ethanol stillage using upflow anaerobic sludge blanket reactor  

SciTech Connect

The anaerobic digestion of wood ethanol stillage in a UASB reactor was studied. At organic loading rates below 16 kg COD/m/sup 3/ day the reactor performed effectively, achieving soluble COD and BOD removals in excess of 86 and 93%, respectively. Removal of color averaged 40%. At a loading rate of 16 kg COD/m/sup 3/ day the methane yield was 0.302 L CH/sub 4/ (STP)/g COD removed, and the observed cell yield was 0.112 g VSS/g COD removed. Operation of the reactor at higher loading rates was unsuccessful. Nitrogen, phosphorus, and alkalinity were supplemented. No additions of the essential trace elements Fe, Co, and Ni were required.

Callander, I.J.; Clark, T.A.; McFarlane, P.N.

1987-01-01

205

Anaerobic digestion of wood ethanol stillage using upflow anaerobic sludge blanket reactor.  

PubMed

The anaerobic digestion of wood ethanol stillage in a UASB reactor was studied. At organic loading rates be low 16 kg COD/m(3) day the reactor performed effectively, achieving soluble COD and BOD removals in excess of 86 and 93%, respectively. Removal of color averaged 40%. At a loading rate of 16 kg COD/m(3) day the methane yield was 0.302 L CH(4) (STP)/g COD removed, and the observed cell yield was 0.112 g VSS/g COD removed. Operation of the reactor at higher loading rates was unsuccessful. Nitrogen, phosphorus, and alkalinity were supplemented. No additions of the essential trace elements Fe, Co, and Ni were required. PMID:18581526

Callander, I J; Clark, T A; McFarlane, P N

1987-11-01

206

Comparison of chemical and biological pretreatment of corn straw for biogas production by anaerobic digestion  

Microsoft Academic Search

In this work, the effects of corn straw pretreatments using Fungus Pleurotus florida and chemicals such as NaOH, ammonia, and urea on the biogasification performance by anaerobic digestion were compared. A laboratory-scale, single-phase and continuous anaerobic biogas digester was used for the evaluation. It was found that after different treatments, the compositional contents of corn straw such as lignin, cellulose,

Weizhang Zhong; Zhongzhi Zhang; Wei Qiao; Pengcheng Fu; Man Liu

2011-01-01

207

Biogas Production of Pig Manure with Water Hyacinth Juice from Batch Anaerobic Digestion  

Microsoft Academic Search

\\u000a Anaerobic digestion, a series of processes in which micro-organisms break down biodegradable materials in the absence of oxygen,\\u000a is normally used for wastewater treatment and energy production. Anaerobic digestion has been applied to hog – wastewater\\u000a treatment and biogas production in the Mekong Delta of Vietnam, where a high percentage of the population works in the agricultural\\u000a sector. However, the

Nguyen Vo Chau Ngan; Le Hoang Viet; Nguyen Dac Cu; Nguyen Huu Phong

208

Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions  

Microsoft Academic Search

Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by

Yong-Hui Song; Guang-Lei Qiu; Peng Yuan; Xiao-Yu Cui; Jian-Feng Peng; Ping Zeng; Liang Duan; Lian-Cheng Xiang; Feng Qian

2011-01-01

209

Anaerobic digestion of by-products of sugar beet and starch potato processing  

Microsoft Academic Search

Anaerobic digestion (AD) is a promising option for the environmentally friendly recycling of agricultural by-products. However, overloading of the digester with sugar, starch or protein might cause inhibition of the anaerobic processes. The aim of the present project was to investigate the AD of sugar beet, starch potato by-products and effect of pre-treatment by steam on methane yield of potatoes

Vitaliy Kryvoruchko; Andrea Machmüller; Vitomir Bodiroza; Barbara Amon; Thomas Amon

2009-01-01

210

Effects of pre-treatment and bioaugmentation strategies on the anaerobic digestion of chicken feathers.  

PubMed

Anaerobic digestion of raw chicken feather waste and its co-digestion with poultry litter were assessed in batch assays. Following, two strategies were evaluated to improve methane production from chicken feathers: (i) waste pre-hydrolysis through thermochemical treatment using lime and sodium hydroxide, and (ii) amendment of digestion broth with the proteolytic bacterium Fervidobacterium pennivorans. Anaerobic digestion of the raw waste (2.5% total solids) allowed a specific methane production of 123 ± 3 L CH(4) kg(-1) VS. Pre-treatment and bioaugmentation strategies did not improve methane production from feather waste, despite the significant increase in waste solubilisation, from 45 ± 5% up to 64 ± 1% using F. pennivorans and up to 96% after pre-treatment with 2g NaOH g(-1) waste. These results indicate that conversion of soluble organic matter to methane, and not the hydrolysis rate, was the limiting step for the anaerobic digestion of chicken feather waste. PMID:22784961

Costa, J C; Barbosa, S G; Sousa, D Z

2012-06-21

211

Life-Cycle Analysis of Energy and Greenhouse Gas Emissions from Anaerobic Biodegradation of Municipal Solid Waste  

Microsoft Academic Search

Energy requirements and greenhouse gas GHG emissions for current landfilling of municipal solid waste MSW was compared to potential biodegradation of MSW in anaerobic digesters AD throughout the United States. A hybrid life-cycle analysis was completed to assess the potential for anaerobic biodegradation of MSW to methane, a valuable energy source. Conversion of MSW to methane in AD would generate

Thomas D. DiStefano

2009-01-01

212

Supercritical fluid extraction of bacterial and archaeal lipid biomarkers from anaerobically digested sludge.  

PubMed

Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile. PMID:22489140

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-03-06

213

Supercritical Fluid Extraction of Bacterial and Archaeal Lipid Biomarkers from Anaerobically Digested Sludge  

PubMed Central

Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile.

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-01-01

214

Feasibility study of the anaerobic digestion of dewatered pig slurry by means of polyacrylamide  

Microsoft Academic Search

Liquid livestock waste can be managed by separating liquid and solid fractions then treating each separately by applying best available technology, such as anaerobic digestion for the solid fraction. There is an increasing use of polyacrylamide (PAM) as a flocculant agent to improve solid–liquid separation. In the present work, the anaerobic toxicity of PAM residues and the optimal range of

E. Campos; M. Almirall; J. Mtnez-Almela; J. Palatsi; X. Flotats

2008-01-01

215

A hybrid anaerobic solid-liquid bioreactor for food waste digestion  

Microsoft Academic Search

A hybrid anaerobic solid-liquid (HASL) bioreactor is an enhanced two-phase anaerobic system, that consists of a solid waste reactor as the acidification reactor and a wastewater reactor, i.e. an upflow anaerobic sludge blanket (UASB) reactor as the methanogenic reactor. Food waste digestion in HASL bioreactors with pre-acidification and HASL operation stages was investigated in two separate runs. After 8 days

Xu Hai-Lou; Wang Jing-Yuan; Tay Joo-Hwa

2002-01-01

216

Assessment of the state of the art of technologies for the processing of digestate residue from anaerobic digesters.  

PubMed

Anaerobic digestion is widely used as an important source of renewable energy. With the increasing number and capacity of biogas plants also, adequate treatment technologies for whole digestate - the residue from anaerobic digestion - are gaining attention. In this study the state of the art of digestate processing is analysed, and currently used treatment schemes and the various technological processes involved are evaluated. The study combines data and experiences from existing large-scale digestate processing facilities in Austria, Germany, Switzerland and Italy, as well as know-how from technology providers and relevant research projects. However, the field of digestate processing is still quite new and little detailed information about the performance of different technologies at industrial scale is available. Digestate processing is gaining importance since digestate utilisation can become an important bottleneck when increasing biogas production. In addition, the production of renewable fertiliser from digestate is increasingly of interest to replace fossil fertilisers. This study is the first profound attempt to establish an assessment of the state-of-the-art technologies in use. PMID:23656941

Fuchs, W; Drosg, B

2013-01-01

217

Anaerobic digestion of chicken feather with swine manure or slaughterhouse sludge for biogas production  

Microsoft Academic Search

Biogas production from anaerobic digestion of chicken feathers with swine manure or slaughterhouse sludge was assessed in two separate experiments. Ground feathers without any pre-treatment were added to 42-L digesters inoculated with swine manure or slaughterhouse sludge, representing 37% and 23% of total solids, respectively and incubated at 25°C in batch mode. Compared to the control without feather addition, total

Yun Xia; Daniel I. Massé; Tim A. McAllister; Carole Beaulieu; Emilio Ungerfeld

218

Removal of helminth eggs and fecal coliforms by anaerobic thermophilic sludge digestion  

Microsoft Academic Search

Anaerobic digestion of two types of waste sludge was applied in order to assess the suitability of thermophilic conditions for the stabilization of organic matter and removal of fecal coliforms and helminth eggs. Feeding sludge was taken from an activated sludge municipal facility (BS) and from an enhanced primary treatment municipal plant (EPT). As an accompanying experiment, mesophilic digesters were

N. Cabirol; M. Rojas Oropeza; A. Noyola

219

ENERGY AND ECONOMIC ASSESSMENT OF ANAEROBIC DIGESTERS AND BIOFUELS FOR RURAL WASTE MANAGEMENT  

EPA Science Inventory

A technological and socioeconomic assessment of anaerobic digester feasibility for small to mid-size livestock operations was undertaken. Three full scale digesters and one pilot scale facility were under various degrees of monitoring and evaluation to assess design and operation...

220

Reactivation and growth of non-culturable indicator bacteria in anaerobically digested biosolids after centrifuge dewatering  

Microsoft Academic Search

Recent literature has reported that high concentrations of indicator bacteria such as fecal coliforms (FCs) were measured in anaerobically digested sludges immediately after dewatering even though low concentrations were measured prior to dewatering. This research hypothesized that the indicator bacteria can enter a non-culturable state during digestion, and are reactivated during centrifuge dewatering. Reactivation is defined as restoration of culturability.

Matthew J. Higgins; Yen-Chih Chen; Sudhir N. Murthy; Donald Hendrickson; Joseph Farrel; Perry Schafer

2007-01-01

221

Biosynthesis of plant hormones during anaerobic digestion of instant coffee waste  

Microsoft Academic Search

A large amount of solid waste remains after the production of instant coffee. This waste has to be moved to dumps, where it poses a threat of environmental pollution. Treatment of this waste by anaerobic methanogenic thermophilic digestion produced, besides biogas, a digested slurry which was used as a growth medium for horticulture, and proved to be a suitable and

D. Kostenberg; U. Marchaim; A. A. Watad; E. Epstein

1995-01-01

222

Thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste  

Microsoft Academic Search

The influence of different organic fraction of municipal solid wastes during anaerobic thermophilic (55°C) treatment of organic matter was studied in this work: food waste (FW), organic fraction of municipal solid waste (OFMSW) and shredded OFMSW (SH_OFMSW). All digester operated at dry conditions (20% total solids content) and were inoculated with 30% (in volume) of mesophilic digested sludge. Experimental results

T. Forster-Carneiro; M. Pérez; L. I. Romero

2008-01-01

223

Pilot plant study of the effects of quebracho and wattle on anaerobic digestion  

SciTech Connect

Quebracho and wattle tannin adversely affected the operational control required for the systems as well as CH4 production. The anaerobic organisms however degraded the tannins and the characteristic red color was effectively removed from the supernatant (liquid phase of digested sludge) during digestion.

Eye, J.D.; Ficker, C.F.

1982-01-01

224

Anaerobic digestion of low-level radioactive cellulosic and animal wastes  

Microsoft Academic Search

A preliminary process design and a cost estimate have been made for a volume reduction plant for low-level, solid radioactive wastes generated at ORNL. The process is based on extension of existing anaerobic digestion technology and on laboratory studies indicating the feasibiity of this technology for digestion of the organic portion of low-level, solid radioactive wastes. A gaseous effluent (COâ

T. L. Donaldson; G. W. Strandberg; B. D. Patton; F. E. Harrington

1983-01-01

225

COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC ANAEROBIC DIGESTION. PHASE 2. STEADY STATE STUDIES  

EPA Science Inventory

A study was conducted of the relative performance of anaerobic digestion systems under mesophilic and thermophilic conditions. Fifty liter laboratory scale digesters were fed primary sludge from the Allentown, PA Waste Water Treatment Plant. Long-term, steady-state performance da...

226

The effect of slurry storage and anaerobic digestion on survival of pathogenic bacteria.  

PubMed

The decline in viable numbers of Salmonella typhimurium, Yersinia enterocolitica and Listeria monocytogene in beef cattle slurry is temperature-dependent; they decline more rapidly at 17 degrees C than at 4 degrees C. Mesophilic anaerobic digestion caused an initial rapid decline in the viable numbers of Escherichia coli, Salm. typhimurium, Y. enterocolitica and L. monocytogenes. This was followed by a period in which the viable numbers were not reduced by 90%. The T90 values of E. coli, Salm. typhimurium and Y. enterocolitica ranged from 0.7 to 0.9 d during batch digestion and 1.1 to 2.5 d during semi-continuous digestion. Listeria monocytogenes had a significantly higher mean T90 value during semi-continuous digestion (35.7 d) than batch digestion (12.3 d). Anaerobic digestion had little effect in reducing the viable numbers of Campylobacter jejuni. PMID:8420921

Kearney, T E; Larkin, M J; Levett, P N

1993-01-01

227

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover.  

PubMed

Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5L/kg VS(feed), while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6L/kg VS(feed). The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3g CaCO(3)/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents. PMID:22958949

Xu, Fuqing; Shi, Jian; Lv, Wen; Yu, Zhongtang; Li, Yebo

2012-09-05

228

Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion.  

PubMed

In the present study we tested four macroalgae species--harvested in Denmark--for their suitability of bioconversion to methane. In batch experiments (53 degrees C) methane yields varied from 132 ml g volatile solids(-1) (VS) for Gracillaria vermiculophylla, 152 mi gVS(-1) for Ulva lactuca, 166 ml g VS(-1) for Chaetomorpha linum and 340 ml g VS(-1) for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5-2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during 'green tides' in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab-scale continuously stirred tank reactor. A 48% increase in methane production rate of the reactor was observed when the concentration of U. lactuca in the feedstock was 40% (VS basis). Increasing the concentration to 50% had no further effect on the methane production, which limits the application of this algae at Danish centralized biogas plant. PMID:22335117

Nielsen, H B; Heiske, S

2011-01-01

229

Evaluation of a microwave-heating anaerobic digester treating municipal secondary sludge.  

PubMed

This work experimentally determined the effect of microwave irradiation on the anaerobic digestion of municipal secondary sludge in semi-continuous mesophilic digesters at hydraulic retention times (HRT) of 15, 10 and 5 days when microwaves were used as a heating source. A microwave-heating anaerobic digester (MHAD) was compared with a water-heating reactor (control). Biogas production increased in both digesters as the HRT decreased except for the control with a HRT of 5 days. Improvement in removal efficiency of volatile solid and biogas production of the MHAD relative to the control increased as the HRT decreased. The results show that the MHAD was more effective than the control in increasing mesophilic anaerobic biodegradability and biogas production treating secondary sludge. PMID:23837339

Jang, Joo-Hyun; Ahn, Johng-Hwa

230

Distribution and abundance of Spirochaetes in full-scale anaerobic digesters.  

PubMed

To investigate the distribution and abundance of spirochaetal communities within anaerobic digesters, pyrosequencing of the 16S rRNA gene was conducted. Phylogenetic analysis identified a cluster which included the majority of core spirochaetal operational taxonomic units (OTUs) and environmental clones but no pure-culture strains. Distribution of the core OTUs demonstrated an importance of local factors in shaping the structure of Spirochaetes. Spirochaetal to bacterial 16S rRNA gene copy numbers varied from 1.3% to 30.0% depending on digester samples. Environmental variables were found to influence the relative abundance of Spirochaetes. In a batch anaerobic digestion experiment testing the response to different substrates, acetate most stimulated the activity of Spirochaetes, suggesting possible acetate oxidation by syntrophic acetate oxidation process. Taken together, the results obtained in this study provides an insight into the ecology of Spirochaetes in anaerobic digesters and a basis for future studies examining ecological function of these bacteria. PMID:23562175

Lee, Sang-Hoon; Park, Jeong-Hoon; Kang, Hyun-Jin; Lee, Young Haeng; Lee, Taek Jun; Park, Hee-Deung

2013-02-27

231

Assessment of the potential for biogas production from wheat straw leachate in upflow anaerobic sludge blanket digesters.  

PubMed

Wheat straw is a major potential source of waste biomass for renewable energy production, but its high salt content causes problems in combustion. The salts can be removed by washing, but this process also removes a proportion of the organic material which could potentially be recovered by anaerobic digestion of the washwater leachate. This approach would maximise the overall energy yield in an integrated process in which washwater could be recycled after further desalting. Leachate from cold water washing with a chemical oxygen demand (COD) of 1.2 g l?¹ was fed to mesophilic upflow anaerobic sludge blanket (UASB) digesters at a loading rate of 1 g COD l?¹ day?¹ to determine the energy yield and any detrimental effects of the leached salts on the process. The specific methane production was 0.29 l CH? g?¹ COD(added), corresponding to a COD removal rate of 84%. Light metal cations in the leachate, especially potassium, were found to accumulate in the digesters and appeared to have a synergistic effect up to a concentration of ?6.5 mg K g?¹ wet weight of the granular sludge, but further accumulation caused inhibition of methanogenesis. It was shown that gas production in the inhibited digesters could be restored within 12 days by switching the feed to a synthetic sewage, which washed the accumulated K out of the digesters. PMID:23109593

Idrus, S; Banks, C J; Heaven, S

2012-01-01

232

Start-up of full-scale anaerobic digesters treating municipal solid waste.  

PubMed

Raising organic loading rate, and the behavior of dissolved CODcr (D-CODcr), VFA and specific methanogen activity, were investigated through a laboratory experiment for the start-up of a sludge recycling center. Moreover, application for MPN-PCR methods using a gene as a direct technique to measure the quantity of methanogen was attempted. It was recognized that specific methanogen activity depends on the quantity of methanogen, and that gas production does not reflect the condition of methane fermentation. The methane fermentation condition was checked through the specific methanogen activity and analysis of D-CODcr. The target organic loading rate was reached in the short period of about 30 days, and rapid start-up was successfully attained for a full-scale anaerobic digester. PMID:14531451

Ohmura, T; Sakai, T; Shindo, Y; Nakamura, K; Ike, T; Katayama, Y

2003-01-01

233

Anaerobic digestion as a sustainable solution for biosolids management by the Montreal metropolitan community.  

PubMed

The Quebec Waste Management Policy (1998-2008) is requesting that the municipalities prepare a waste management plan, including a global objective of 60% of these wastes to be diverted from landfill sites by reduction, re-usage, recycling and valorization. Around 5.8 million tons of wastes were generated on the territory of the Montreal Metropolitan Community in 2001 for a population of about 3.5 millions citizens. In this paper, we present different management scenarios in which anaerobic digestion was used as a valorization step, focusing on the energetic value of the methane produced and the reduction in greenhouse gas (GHG) emissions. The four scenarios prepared cover the valorization of the organic fraction of municipal solid wastes, green wastes and excess sludge and showed potential methane generation of 17-140 Mm3 with a GHG reduction of 62,000-500,000 tons of CO2-equivalents. PMID:16180478

Frigon, J C; Guiot, S R

2005-01-01

234

Size distribution of airborne particulate matter emitted by the front-end processing of municipal solid waste feed material for large-scale anaerobic digesters  

Microsoft Academic Search

A 100-ton\\/day proof-of-concept facility has been constructed in Pompano Beach, Florida, to examine the feasibility of producing methane-rich gas from the anaerobic digestion of municipal solid waste. One of the possible environmental impacts is from the particulate matter emitted into the atmosphere by the secondary shredding and conveying of light fraction feed material to the digesters. It has been found

H. P. Gerrish; R. Narasimhan; E. L. Jr. Daly; S. Sengupta; N. L. Nemerow; K. V. Wong

1984-01-01

235

Size Distribution of Airborne Particuiate Matter Emitted by the Front-End Processing of Municipal Soiid Waste Feed Material for Large-Scale Anaerobic Digesters  

Microsoft Academic Search

A 100-ton\\/day proof-of-concept facility has been constructed in Pompano Beach, Florida, to examine the feasibility of producing methane-rich gas from the anaerobic digestion of municipal solid waste. One of the possible environmental impacts is from the particuiate matter emitted into the atmosphere by the secondary shredding and conveying of light fraction feed material to the digesters. It has been found

H. P. Gerrish; R. Narasimhan; E. L. Daly Jr; S. Sengupta; N. L. Nemerow; K. V. Wong

1984-01-01

236

Anaerobic digestion: principles and practices for biogas systems. World Bank technical paper  

SciTech Connect

The report is part of a joint global research, development, and demonstration effort of the United Nations Development Programme and the World Bank. It explores the history, technology, and applications of anaerobic digestion, the biological process by which organic materials are degraded in the absence of oxygen to produce a combustible gas, methane (CH/sub 4/), and carbon dioxide (CO/sub 2/). The process occurs naturally in wet, decaying organic matter (biomass) found in swamps, bottom muds of streams, and garbage dumps. Since about 1900, it has been used in engineered systems for treatment and stabilization of municipal or industrial sludges. Starting around 1920, systems have been operated so as to capture the biogas, identical to marsh gas which contains about 55-75 percent methane, as an energy source. In addition to producing a fuel substitute, benefits of digestion include reduction or elimination of pathogens in human and animal wastes and production of a stable, generally environmentally acceptable slurry or sludge that can be used as a fertilizer and soil conditioner.

Gunnerson, C.G.; Stuckey, D.C.

1986-01-01

237

MICROBIAL DESTRUCTIONS ACHIEVED BY FULL-SCALE ANAEROBIC DIGESTION  

EPA Science Inventory

As part of studies undertaken to investigate the pathogen reducing capabilities of conventional sludge stabilization procedures, microbial reductions produced by mesophilic and thermophilic digestion at the Los Angeles Hyperion Plant were examined. Samples from the digester feed ...

238

Anaerobic co-digestion of the marine microalga Nannochloropsis salina with energy crops.  

PubMed

Anaerobic co-digestion of corn silage with the marine microalga Nannochloropsis salina was investigated under batch and semi-continuous conditions. Under batch conditions process stability and biogas yields significantly increased by microalgae addition. During semi-continuous long-term experiments anaerobic digestion was stable in corn silage mono- and co-digestion with the algal biomass for more than 200days. At higher organic loading rates (4.7kg volatile solids m(-3)d(-1)) inhibition and finally process failure occurred in corn silage mono-digestion, whereas acid and methane formation remained balanced in co-digestion. The positive influences in co-digestion can be attributed to an adjusted carbon to nitrogen ratio, enhanced alkalinity, essential trace elements and a balanced nutrient composition. The results suggest that N. salina biomass is a suitable feedstock for anaerobic co-digestion of energy crops, especially for regions with manure scarcity. Enhanced process stability may result in higher organic loading rates or lower digester volumes. PMID:24071442

Schwede, Sebastian; Kowalczyk, Alexandra; Gerber, Mandy; Span, Roland

2013-09-06

239

Blending anaerobic co-digestates: synergism and economics.  

PubMed

Co-digestion is the process in which wastes from various sources are treated together. Therefore, more organic carbon is added to make efficient use of existing digesters. The objectives of this study were to compare potential co-digestates, determine synergistic and antagonistic co-digestion outcomes and estimate economic benefits for preliminary screening. Over 80 wastes were identified from 54 facilities within 160 km of an existing municipal digester. Synergistic, antagonistic and neutral co-digestion outcomes were observed for the various wastes. A simple economic comparison resulted in the greatest potential benefits for four co-digestates: yeast flavorings production waste, meat production dissolved air flotation float, acid whey from cheese production and thin stillage from corn ethanol production. Performance was investigated using bench-scale digesters receiving primary sludge with and without co-digestates. Methane production rates were 105 and 66% higher when co-digestates were present, but were anticipated to increase only 57 and 23% due to the additional chemical oxygen demand. Therefore, significant synergistic outcomes were observed during co-digestion. Co-digestion of the most promising wastes with primary sludge in full scale was estimated to generate enough electricity to power more than 2,500 houses. PMID:22049719

Navaneethan, N; Topczewski, P; Royer, S; Zitomer, D

2011-01-01

240

The Effect of Higher Sludge Recycling Rate on Anaerobic Treatment of Palm Oil Mill Effluent in a Semi-Commercial Closed Digester for Renewable Energy  

Microsoft Academic Search

Problem statement: A 500 m 3 semi-commercial closed anaerobic digester was constructed for Palm Oil Mill Effluent (POME) treatment and methane gas capture for renewable energy. During the start-up operation period, the Volatile Fatty A cids (VFA) accumulation could not be controlled and caused instability on the system. Approach: A settling tank was installed and sludge was recycl ed as

Alawi Sulaiman; Zainuri Busu; Meisam Tabatabaei; Shahrakbah Yacob; Suraini Abd-Aziz; Mohd Ali Hassan; Yoshihito Shirai

2009-01-01

241

Inhibition of the anaerobic digestion process by linear alkylbenzene sulfonates  

Microsoft Academic Search

Linear Alkylbenzene Sulfonates (LAS) are the most widely used synthetic anionicsurfactants. They are anthropogenic, toxic compounds and are found in the primarysludge generated in municipal wastewater treatment plants. Primary sludge is usuallystabilized anaerobically and therefore it is important to investigate the effect of thesexenobiotic compounds on an anaerobic environment. The inhibitory effect of LinearAlkylbenzene Sulfonates (LAS) on the acetogenic and

Hariklia N. Gavala; Birgitte K. Ahring

2002-01-01

242

Anaerobic digestion of chicken feather with swine manure or slaughterhouse sludge for biogas production.  

PubMed

Biogas production from anaerobic digestion of chicken feathers with swine manure or slaughterhouse sludge was assessed in two separate experiments. Ground feathers without any pre-treatment were added to 42-L digesters inoculated with swine manure or slaughterhouse sludge, representing 37% and 23% of total solids, respectively and incubated at 25°C in batch mode. Compared to the control without feather addition, total CH(4) production increased by 130% (P<0.001) and 110% (P=0.09) in the swine manure and the slaughterhouse sludge digesters, respectively. Mixed liquor NH(4)N concentration increased (P<0.001) from 4.8 and 3.1g/L at the beginning of the digestion to 6.9 and 3.5 g/L at the end of digestion in the swine manure and the slaughterhouse sludge digesters, respectively. The fraction of proteolytic microorganisms increased (P<0.001) during the digestion from 12.5% to 14.5% and 11.3% to 13.0% in the swine manure and the slaughterhouse sludge digesters with feather addition, respectively, but decreased in the controls. These results are reflective of feather digestion. Feather addition did not affect CH(4) yields of the swine manure digesters (P=0.082) and the slaughterhouse sludge digesters (P=0.21), indicating that feathers can be digested together with swine manure or slaughterhouse sludge without negatively affecting the digestion of swine manure and slaughterhouse sludge. PMID:22088961

Xia, Yun; Massé, Daniel I; McAllister, Tim A; Beaulieu, Carole; Ungerfeld, Emilio

2011-11-15

243

Monitoring bacterial community structure and variability in time scale in full-scale anaerobic digesters.  

PubMed

Using a high-throughput pyrosequencing technology, this study assessed bacterial community structure and time-scale variability in great detail in seven full-scale anaerobic digesters operated variously in terms of influent substrate, digestion temperature, and reactor configuration. Pyrosequencing generated a total of 83,774 sequence reads from 40 digester sludge samples collected monthly for six months. The highest number of sequence reads were detected within Proteobacteria (20.5%), followed by those within Bacteroidetes (19.7%), Firmicutes (17.8%), and Chloroflexi (4.8%). The relative composition of bacterial populations was varied within the digesters as well as between the digesters, and the bacterial community structures were mainly influenced by digestion temperature. Detailed bacterial community structures were assessed by analyzing the operational taxonomic units (OTUs) based on 97% sequence similarity, which resulted in a total of 9051 OTUs. Among these, a total of 31 core OTUs were analyzed and inferred phylogenetically, which enabled us to classify the sequences within an unclassified phylum. Unclassified sequences were mostly affiliated with the sequences within Spirochaetes and Firmicutes. Interestingly, numerically dominant novel phylotypes (18% of the total sequence reads) presumably involved in anaerobic digestion within Spirochaetes were identified. Temporal variability was further explored using a non-metric multidimensional scaling ordination which demonstrated that the variability of the bacterial community within the digesters was smaller than between digesters. Correlation analysis demonstrated that digester performance and operational conditions affected the pattern of bacterial community in the ordination. Additionally, a multi-response permutation procedure revealed that the bacterial communities within the digesters were more similar than those belonging to other digesters statistically, demonstrating a patchiness of the digesters in the distribution of bacterial populations. Overall, this study revealed the correlation of bacterial community structure and time-scale variability with digester performance and operating conditions. PMID:22426622

Lee, Sang-Hoon; Kang, Hyun-Jin; Lee, Young Haeng; Lee, Taek Jun; Han, Keumsuk; Choi, Youngjun; Park, Hee-Deung

2012-03-19

244

High-solids anaerobic digestion of mixed municipal and industrial waste  

SciTech Connect

Laboratory studies on dry anaerobic digestion of mixture of paper, kitchen food waste, and sewage sludge have demonstrated the optimum performance at total solids (TS) at the range of 30--35% TS. The thermophilic process (at 55 C) was found to be superior to a mesophilic (35 C) one, both in terms of volatile solid (VS) reduction and specific gas production, but was somewhat less stable at short mass retention times (MRT). The efficiency of total volatile solids destruction and the decrease in the oxygen demand were found to be proportional to the product of the mass retention time and temperature (d {center_dot} C). Pilot studies, conducted on a mixture of sewage sludge, mixed paper, food waste, and solids from a potato processing conducted on site in Portage la Prairie, Manitoba, Canada, have demonstrated the feasibility of running the process at loads exceeding 9 kg TS/m{sup 3} {center_dot} d and producing biogas at 140 m{sup 3} of wet solids fed to the composter. The residual oxygen demand per unit mass of the dry compost was 20 mg O{sub 2}/g {center_dot} h, which indicated a need for aerobic postcuring of the anaerobically produced compost.

Oleszkiewicz, J.A.; Poggi-Varaldo, H.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Civil Engineering

1997-11-01

245

Anaerobic Digestion for Simultaneous Sewage Sludge Treatment and CO Biomethanation: Process Performance and Microbial Ecology.  

PubMed

Syngas is produced by thermal gasification of both nonrenewable and renewable sources including biomass and coal, and it consists mainly of CO, CO2, and H2. In this paper we aim to bioconvert CO in the syngas to CH4. A novel technology for simultaneous sewage sludge treatment and CO biomethanation in an anaerobic reactor was presented. Batch experiments showed that CO was inhibitory to methanogens, but not to bacteria, at CO partial pressure between 0.25 and 1 atm under thermophilic conditions. During anaerobic digestion of sewage sludge supplemented with CO added through a hollow fiber membrane (HFM) module in continuous thermophilic reactors, CO did not inhibit the process even at a pressure as high as 1.58 atm inside the HFM, due to the low dissolved CO concentration in the liquid. Complete consumption of CO was achieved with CO gas retention time of 0.2 d. Results from high-throughput sequencing analysis showed clear differences of the microbial community structures between the samples from liquid and biofilm on the HFM in the reactor with CO addition. Species close to Methanosarcina barkeri and Methanothermobacter thermautotrophicus were the two main archaeal species involved in CO biomethanation. However, the two species were distributed differently in the liquid phase and in the biofilm. Although the carboxidotrophic activities test showed that CO was converted by both archaea and bacteria, the bacterial species responsible for CO conversion are unknown. PMID:23952148

Luo, Gang; Wang, Wen; Angelidaki, Irini

2013-09-04

246

Long-term anaerobic digestion of food waste stabilized by trace elements.  

PubMed

The purpose of this study was to examine if long-term anaerobic digestion of food waste in a semi-continuous single-stage reactor could be stabilized by supplementing trace elements. Contrary to the failure of anaerobic digestion of food waste alone, stable anaerobic digestion of food waste was achieved for 368 days by supplementing trace elements. Under the conditions of OLR (organic loading rates) of 2.19-6.64 g VS (volatile solid)/L day and 20-30 days of HRT (hydraulic retention time), a high methane yield (352-450 mL CH(4)/g VS(added)) was obtained, and no significant accumulation of volatile fatty acids was observed. The subsequent investigation on effects of individual trace elements (Co, Fe, Mo and Ni) showed that iron was essential for maintaining stable methane production. These results proved that the food waste used in this study was deficient in trace elements. PMID:22537972

Zhang, Lei; Jahng, Deokjin

2012-04-24

247

Effects of total ammonia nitrogen concentration on solid-state anaerobic digestion of corn stover.  

PubMed

The inhibitive effect of total ammonia nitrogen (TAN) (including NH3 and NH4(+)) on solid-state anaerobic digestion of corn stover was investigated in batch reactors at 37°C. The highest methane yield of 107.0L/kg VSfeed was obtained at a TAN concentration of 2.5g/kg (based on total weight). TAN concentrations greater than 2.5g/kg resulted in decreased methane yields, with a 50% reduction observed at a concentration of 6.0g/kg. Reduced reaction rates and microbial activities for hydrolysis of cellulose and methanogenesis from acetate were observed at TAN concentrations higher than 4.3g/kg. Strong ammonia stress was indicated at butyrate concentrations higher than 300mg/kg. Result showed that the effluent of liquid anaerobic digestion can provide enough nitrogen for solid-state anaerobic digestion of corn stover. PMID:23880129

Wang, Zhongjiang; Xu, Fuqing; Li, Yebo

2013-07-02

248

Biochemical methane potential and solid state anaerobic digestion of Korean food wastes  

Microsoft Academic Search

In order to develop an anaerobic digestion process for Korean food wastes containing 15–30% total solids (TS) the biochemical methane potentials (BMP) of their components and mixture (mixed food waste, MFW) were measured. The methane yields of cooked meat, cellulose (as control), boiled rice, fresh cabbage and MFW were 482, 356, 294, 277 and 472 ml CH4\\/gVS added and anaerobic

Ho Nam Chang; Soon Chul Park

1995-01-01

249

Modelling and Dynamic Compensator Control of the Anaerobic Digestion of Organic Wastes  

Microsoft Academic Search

The paper deals with the modelling and control of anaerobic fermentation processes (anaerobic digestion). Laboratory experiments have been carried out on an automated laboratory-scale biogas unit. For this process 2nd and 5th order non-linear models have been considered. A simple methodology for parameters estimation, based on non-linear optimisation method, has been developed. The control is reduced to the regulation of

I. Simeonov; S. Stoyanov

2003-01-01

250

Kinetic analysis of anaerobic digestion of cattail by rumen microbes in a modified UASB reactor  

Microsoft Academic Search

The kinetics of anaerobic digestion of cattail by rumen microbes in a modified upflow anaerobic sludge blanket (UASB) reactor was systematically analyzed in this study. The Monod and first-order equations were combined to develop kinetic models to describe the substrate degradation, microbial growth and product formation. At an influent cattail concentration (volatile solids) of 12.1g\\/L, hydraulic retention time of 0.75

Zhen-Hu Hu; Han-Qing Yu; Zheng-Bo Yue; Hideki Harada; Yu-You Li

2007-01-01

251

Impact of nano zero valent iron (NZVI) on methanogenic activity and population dynamics in anaerobic digestion.  

PubMed

Nano zero valent iron (NZVI), although being increasingly used for environmental remediation, has potential negative impact on methanogenesis in anaerobic digestion. In this study, NZVI (average size = 55 ± 11 nm) showed inhibition of methanogenesis due to its disruption of cell integrity. The inhibition was coincident with the fast hydrogen production and accumulation due to NZVI dissolution under anaerobic conditions. At the concentrations of 1 mM and above, NZVI reduced methane production by more than 20%. At the concentration of 30 mM, NZVI led to a significant increase in soluble COD (an indication of cell disruption) and volatile fatty acids in the mixed liquor along with an accumulation of H2, resulting in a reduction of methane production by 69% (±4% [standard deviation]). By adding a specific methanogenesis inhibitor-sodium 2-bromoethanesulfonate (BES) to the anaerobic sludge containing 30 mM NZVI, the amount of H2 produced was only 79% (±1%) of that with heat-killed sludge, indicating the occurrence of bacterially controlled hydrogen utilization processes. Quantitative PCR data was in accordance with the result of methanogenesis inhibition, as the level of methanogenic population (dominated by Methanosaeta) in the presence of 30 mM NZVI decreased significantly compared to that of the control. On the contrary, ZVI powder (average size <212 ?m) at the same concentration (30 mM) increased methane production presumably due to hydrogenotrophic methanogenesis of hydrogen gas that was slowly released from the NZVI powder. While it is a known fact that NZVI disrupts cell membranes, which inhibited methanogenesis described herein, the results suggest that the rapid hydrogen production due to NZVI dissolution also contribute to methanogenesis inhibition and lead to bacterially controlled hydrogenotrophic processes. PMID:24112628

Yang, Yu; Guo, Jialiang; Hu, Zhiqiang

2013-09-27

252

Biodegradability of degradable plastics exposed to anaerobic digested sludge and simulated landfill conditions  

Microsoft Academic Search

The biodegradabilities of various plastics by anaerobic digested sludge were measured and compared with the biodegradabilities\\u000a under simulated landfill conditions. Bacterial poly(3-hydroxy-butyrate-co-3-hydroxyvalerate) (PHB\\/HV; 92\\/8, w\\/w), a natural\\u000a aliphatic polyester, degraded nearly to completion within 20 days of cultivation by anaerobic digested sludge, while synthetic\\u000a aliphatic polyesters such as poly-lactic acid, poly(butylene succinate), and poly (butylene succinate-co-ethylene succinate)\\u000a did not degrade

Pyong Kyun Shin; Myung Hee Kim; Jong Min Kim

1997-01-01

253

Contribution of anaerobic digesters to emissions mitigation and electricity generation under U.S. climate policy.  

PubMed

Livestock husbandry in the U.S. significantly contributes to many environmental problems, including the release of methane, a potent greenhouse gas (GHG). Anaerobic digesters (ADs) break down organic wastes using bacteria that produce methane, which can be collected and combusted to generate electricity. ADs also reduce odors and pathogens that are common with manure storage and the digested manure can be used as a fertilizer. There are relatively few ADs in the U.S., mainly due to their high capital costs. We use the MIT Emissions Prediction and Policy Analysis (EPPA) model to test the effects of a representative U.S. climate stabilization policy on the adoption of ADs which sell electricity and generate methane mitigation credits. Under such policy, ADs become competitive at producing electricity in 2025, when they receive methane reduction credits and electricity from fossil fuels becomes more expensive. We find that ADs have the potential to generate 5.5% of U.S. electricity. PMID:21761880

Zaks, David P M; Winchester, Niven; Kucharik, Christopher J; Barford, Carol C; Paltsev, Sergey; Reilly, John M

2011-07-26

254

Microbial Ecology of Thermophilic Anaerobic Digestion: (Progress Report, Year 3).  

National Technical Information Service (NTIS)

The goal of this project is to gain a more complete understanding of the microorganisms converting a lignocellulose waste to methane in a thermophilic (58/degree/C) anaerobic bioreactor. We have directly examined microbial populations in the bioreactor an...

S. H. Zinder

1988-01-01

255

Microbial Ecology of Thermophilic Anaerobic Digestion: Progress Report, Year 4.  

National Technical Information Service (NTIS)

The goal of this project is to gain a more complete understanding of the microorganisms converting a lignocellulose waste to methane in a thermophilic (58/degree/C) anaerobic bioreactor. We have directly examined microbial populations in the bioreactor an...

S. H. Zinder

1988-01-01

256

Bioaugmenting anaerobic digestion of biosolids with selected strains of Bacillus , Pseudomonas , and Actinomycetes species for increased methanogenesis and odor control  

Microsoft Academic Search

The objective of this study was to evaluate the effects of bioaugmenting anaerobic biosolids digestion with a commercial product containing selected strains of bacteria from genera Bacillus, Pseudomonas, and Actinomycetes, along with ancillary organic compounds containing various micronutrients. Specifically, the effects of the bioaugment in terms of volatile solids destruction and generation and fate of odor-causing compounds during anaerobic digestion

Metin Duran; Nalan Tepe; Deniz Yurtsever; Vito L. Punzi; Charles Bruno; Raj J. Mehta

2006-01-01

257

Effect of ultrasound pretreatment in mesophilic and thermophilic anaerobic digestion with emphasis on naphthalene and pyrene removal  

Microsoft Academic Search

In many anaerobic digestion processes for the treatment of the sludge produced in wastewater treatment plants, the hydrolysis of the organic matter has been identified as the rate limiting step. This study is focused on the effect of ultrasonic pretreatment of raw sewage sludge before being fed to the mesophilic and the thermophilic anaerobic digestion. From particle size reduction, COD

T. Benabdallah El-Hadj; J. Dosta; R. Márquez-Serrano; J. Mata-Álvarez

2007-01-01

258

AN INNOVATIVE DESIGN FOR ANAEROBIC CO-DIGESTION OF ANIMAL WASTES FOR SUSTAINABLE DEVELOPMENT IN RURAL COMMUNITIES  

EPA Science Inventory

With the aim of the Phase I project to develop an innovative anaerobic co-digestion design for the treatment of dairy manure and poultry waste, our Phase I team has evaluated the technical and economic feasibility of the anaerobic co-digestion design concept with a thorough in...

259

Potential for energy generation from anaerobic digestion of food waste in Australia.  

PubMed

Published national and state reports have revealed that Australia deposits an average of 16 million Mg of solid waste into landfills yearly, of which approximately 12.6% is comprised of food. Being highly biodegradable and possessing high energy content, anaerobic digestion offers an attractive treatment option alternative to landfilling. The present study attempted to identify the theoretical maximum benefit of food waste digestion in Australia with regard to energy recovery and waste diversion from landfills. The study also assessed the scope for anaerobic process to utilize waste for energy projects through various case study scenarios. Results indicated anaerobic digestion of total food waste generated across multiple sites in Australia could generate 558 453 dam(3) of methane which translated to 20.3 PJ of heating potential or 1915 GWe in electricity generation annually. This would contribute to 3.5% of total current energy supply from renewable sources. Energy contribution from anaerobic digestion of food waste to the total energy requirement in Australia remains low, partially due to the high energy consumption of the country. However its appropriateness in low density regions, which are prevalent in Australia, may allow digesters to have a niche application in the country. PMID:23381970

Lou, Xian Fang; Nair, Jaya; Ho, Goen

2013-02-04

260

Phase distribution and removal of pharmaceuticals and personal care products during anaerobic sludge digestion.  

PubMed

The fate and removal of 48 pharmaceuticals and personal care products (PPCPs) during anaerobic digestion of sewage sludge were investigated in four full-scale sewage treatment plants (STPs). We measured concentrations in both the liquid and solid phases of the sludge to compare the distribution ratios (Kd) between phases before and after digestion. The results showed changes in Kd values of PPCPs with carboxyl or amino functional groups, probably due to a shift of dissociation equilibrium with the increase in pH. Sulfamethoxazole and trimethoprim were almost completely degraded (>90%); triclosan, triclocarban, and ofloxacin were moderately degraded (around 30-50%); but carbamazepine was not eliminated. To our knowledge, this is the first report that shows (i) the occurrence and removal of several tens of PPCPs by anaerobic sludge digestion in full-scale municipal STPs and (ii) the change of distribution between the liquid and solid phases during digestion. PMID:23774781

Narumiya, Masanori; Nakada, Norihide; Yamashita, Naoyuki; Tanaka, Hiroaki

2013-05-25

261

DEMONSTRATION OF THERMOPHILIC AEROBIC-ANAEROBIC DIGESTION AT HAGERSTOWN, MARYLAND  

EPA Science Inventory

This report describes the successful operation of a new and novel approach to digestion of sludge at the Hagerstown wastewater treatment plant. The process, known as dual digestion, involved the coupling of a full-scale experimental aerobic reactor to an existing full-scale anaer...

262

Modeling of two-phase anaerobic process treating traditional Chinese medicine wastewater with the IWA Anaerobic Digestion Model No. 1.  

PubMed

The aim of the study was to implement a mathematical model to simulate two-phase anaerobic digestion (TPAD) process which consisted of an anaerobic continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket (UASB) reactor in series treating traditional Chinese medicine (TCM) wastewater. A model was built on the basis of Anaerobic Digestion Model No. 1 (ADM1) while considering complete mixing model for the CSTR, and axial direction discrete model and mixed series connection model for the UASB. The mathematical model was implemented with the simulation software package MATLABTM/Simulinks. System performance, in terms of COD removal, volatile fatty acids (VFA) accumulation and pH fluctuation, was simulated and compared with the measured values. The simulation results indicated that the model built was able to well predict the COD removal rate (-4.8-5.0%) and pH variation (-2.9-1.4%) of the UASB reactor, while failed to simulate the CSTR performance. Comparing to the measured results, the simulated acetic acid concentration of the CSTR effluent was underpredicted with a deviation ratios of 13.8-23.2%, resulting in an underprediction of total VFA and COD concentrations despite good estimation of propionic acid, butyric acid and valeric acid. It is presumed that ethanol present in the raw wastewater was converted into acetic acid during the acidification process, which was not considered by the model. Additionally, due to the underprediction of acetic acid the pH of CSTR effluent was overestimated. PMID:19477121

Chen, Zhaobo; Hu, Dongxue; Zhang, Zhenpeng; Ren, Nanqi; Zhu, Haibo

2009-05-23

263

A comparison of analytical techniques for evaluating food waste degradation by anaerobic digestion  

Microsoft Academic Search

Organic matter contained in food waste was degraded by anaerobic digestion under mesophilic and thermophilic conditions at\\u000a two hydraulic retention times. Evolution of the digestion process was followed by thermogravimetry analysis, fluorescence\\u000a spectroscopy and 1H nuclear magnetic resonance. All analytical methods suggested that longer retention times might be required for food waste\\u000a stabilization under mesophilic conditions as compared to thermophilic

X. Gómez; M. J. Cuetos; B. Tartakovsky; M. F. Martínez-Núñez; A. Morán

2010-01-01

264

Biochar derived from anaerobically digested sugar beet tailings: Characterization and phosphate removal potential  

Microsoft Academic Search

Two biochars were produced from anaerobically digested and undigested sugar beet tailings through slow-pyrolysis at 600°C. The digested sugar beet tailing biochar (DSTC) and raw sugar beet tailing biochar (STC) yields were around 45.5% and 36.3% of initial dry weight, respectively. Compared to STC, DSTC had similar pH and surface functional groups, but higher surface area, and its surface was

Ying Yao; Bin Gao; Mandu Inyang; Andrew R. Zimmerman; Xinde Cao; Pratap Pullammanappallil; Liuyan Yang

2011-01-01

265

Bipolar effects of settling time on active biomass retention in anaerobic sequencing batch reactors digesting flushed dairy manure  

Microsoft Academic Search

Active biomass retention is a technical challenge in anaerobic digester treating dilute animal manure that contains solids particles. A strategy was tested using fibers in the dairy manure as biomass carriers by controlling settling time. Settling time ranging from 0.5 to 60min were applied to eight anaerobic sequencing batch reactors to investigate their effects on active biomass retention in anaerobic

Zhi-Wu Wang; Jingwei Ma; Shulin Chen

2011-01-01

266

Reduced Gas Pressure Operation of Sludge Digesters: Expanded Studies.  

National Technical Information Service (NTIS)

Previous investigations strongly suggested that the municipal anaerobic sludge digestion process could be enhanced by reactor operation with subatmospheric headspace pressures. Enhanced solids destruction and methane production along with increased proces...

A. A. Friedman

1993-01-01

267

Fate and toxicity of aircraft deicing fluid additives through anaerobic digestion.  

PubMed

Benzotriazole derivatives are widely used corrosion inhibitors and their fate during wastewater treatment processes is unknown. The purpose of this research was to study the toxic effects and fate of the two commercially significant benzotriazole isomers used in aircraft deicing fluids (4-, and 5-, methylbenzotriazole [MeBT]) during anaerobic digestion. Experiments were executed in microcosms using mesophilic anaerobic biomass co-digesting wastewater sludge and propylene glycol. Sorption of MeBT to digesting solids could be approximated with a Freundlich model, and no anaerobic breakdown of either MeBT isomer was detected. Digesters fed more than 300 mg/L MeBT responded with a significant decrease in methanogenic microbial activity and volatile solids production and a concomitant increase in accumulation of volatile fatty acids. Direct microscopic measurements using fluorescent phylogenetic probes applied to digesting biomass revealed that members of both Archaea and Bacteria domains were sensitive to MeBT. Granular activated carbon (GAC) (volatile solids: GAC = 10%) reduced the apparent toxic effects of MeBT; GAC addition nearly restored the baseline activity of digesters fed MeBT (500 to 1000 mg/L). PMID:11558306

Gruden, C L; Dow, S M; Hernandez, M T

268

Anaerobic co-digestion of dairy manure with mulched switchgrass for improvement of the methane yield.  

PubMed

The owners of farm-scale anaerobic digesters are relying on off-farm wastes or energy crops as a co-digestion feedstock with animal manure in order to increase their production of methane and thus revenues. Switchgrass represents an interesting feedstock for Canadian digesters owners as it is a high-yielding low-maintenance perennial crop, well adapted to northern climate. Methane potential assays in batch tests showed methane production of 19.4 ± 3.6, 28.3 ± 1.7, 37.3 ± 7.1 and 45.7 ± 0.8 L kg(-1), for raw manure, blended manure, manure and mulched switchgrass, manure and pretreated switchgrass, respectively. Two 6-L lab-scale anaerobic digesters were operated for 130 days in order to assess the benefit of co-digesting switchgrass with bovine manure (digester #2), at a 20% wet mass fraction, compared with a manure-only operation (digester #1) The digesters were operated at an hydraulic retention time of 37 ± 6 days and at loads of 2.4 ± 0.6 and 2.6 ± 0.6 kg total volatile solids (TVS) L(-1) day(-1) for digesters #1 (D1) and #2 (D2), respectively. The TVS degradation reached 25 and 39%, which resulted in a methane production of 1.18 ± 0.18 and 2.19 ± 0.31 L day(-1) for D1 and D2, respectively. The addition of 20% on a wet mass ratio of switchgrass to a manure digester increased its methane production by 86%. The co-digestion of switchgrass in a 500 m(3) manure digester could yield up to 10.2 GJ day(-1) of purified methane or 1.1 MWh day(-1) of electricity. PMID:21779889

Frigon, Jean-Claude; Roy, Caroline; Guiot, Serge R

2011-07-22

269

Detailed study of anaerobic digestion of Spirulina maxima algae biomass  

Microsoft Academic Search

Biomass of the blue-green alga Spirulina maxima was converted to methane using continuous stirred tank digesters with an energy conversion efficiency of 59%. Digesters were operated using once-a-day feeding with a retention time (theta) between 5 and 40 days, volatile solid concentrations (Sto) between 20 and 100 kg VS\\/cubic m, and temperatures between 15 and 52°C. The results indicated a

Réjean Samson; A. LeDuy

1986-01-01

270

Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.  

PubMed

The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%. PMID:17251012

Zupancic, Gregor D; Ros, Milenko

2007-01-23

271

ANAEROBIC DIGESTION OF MICROALGAE: MODELING AND IDENTIFICATION FOR OPTIMIZATION AND CONTROL  

Microsoft Academic Search

Owing to the rise in fossil fuel prices, overall energy security concerns, and the current push towards green engineering; renewable and green fuels have seen an increase in interest in recent years. Two notable technologies in this green movement are the production of biodiesel from microalgae and the production of biogas from anaerobic digestion of waste biomass. Production of biodiesel

Elliot T Cameron

2012-01-01

272

The mesophilic and thermophilic anaerobic digestion of coffee waste containing coffee grounds  

Microsoft Academic Search

The anaerobic digestion of waste water containing significant levels of coffee grounds was assessed in mesophilic and thermophilic batch studies and CSTRs fed daily. A 58% reduction in VS was seen in both batch studies. Proximate compositional analysis showed that the waste had a high lipid component (26–33%). Levels of lipid, hemicellulose, ?-cellulose and lignin were determined before and after

Richard M. Dinsdale; Freda R. Hawkes; Dennis L. Hawkes

1996-01-01

273

Simplified hydrolysis models for the optimal design of two-stage anaerobic digestion.  

PubMed

This note shows that Contois kinetics, when used to describe the hydrolysis of biodegradable solids, are preferable to the traditional first-order kinetics when considering the optimal design of a steady-state two-stage anaerobic digester system. PMID:11791857

Vavilin, V A; Rytov, S V; Lokshina, L Y; Rintala, J A; Lyberatos, G

2001-12-01

274

Effect of total solids on fecal coliform regrowth in anaerobically digested biosolids  

Microsoft Academic Search

Fecal coliform (FC) concentrations in anaerobically digested biosolids can increase during centrifugal dewatering and afterwards in storage of dewatered cake. The immediate increase after centrifugation (reactivation) has been demonstrated to be the revitalization of fecal coliforms that had become non-culturable. The increase during storage (regrowth) has been regarded as a subsequence of reactivated bacteria growing in a favorable environment. In

Yinan Qi; Steven K. Dentel; Diane S. Herson

2008-01-01

275

Treatment of anaerobic sludge digester effluents by the CANON process in an air pulsing SBR  

Microsoft Academic Search

The CANON (Completely Autotrophic Nitrogen removal Over Nitrite) process was successfully developed in an air pulsing reactor type SBR fed with the supernatant from an anaerobic sludge digester and operated at moderately low temperatures (18–24°C). The SBR was started up as a nitrifying reactor, lowering progressively the dissolved oxygen concentration until reaching partial nitrification. Afterwards, an inoculation with sludge containing

J. R. Vázquez-Padín; M. J. Pozo; M. Jarpa; M. Figueroa; A. Franco; A. Mosquera-Corral; J. L. Campos; R. Méndez

2009-01-01

276

Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants.  

PubMed

Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea. PMID:12043972

Gruden, Cyndee L; Hernandez, Mark

277

Toxicity of linear alkylbenzene sulfonate in anaerobic digestion: influence of exposure time  

Microsoft Academic Search

The inhibition of anaerobic digestion by the anionic surfactant linear alkylbenzene sulfonate was studied. The development of bacterial activity during several weeks was monitored by performing batch degradation tests with acetate and propionate. In the first phase the decay of activity without surfactant addition was studied. After the addition of the surfactant an immediate inhibition was detected. Subsequently, the degradation

M Mösche; U Meyer

2002-01-01

278

40 CFR Table Jj-6 to Subpart Jj of... - Collection Efficiencies of Anaerobic Digesters  

Code of Federal Regulations, 2011 CFR

...Collection Efficiencies of Anaerobic Digesters JJ Table JJ-6 to Subpart JJ of Part 98 Protection of Environment ...Manure Management Pt. 98, Subpt. JJ, Table JJ-6 Table JJ-6 to Subpart JJ of Part 98âCollection Efficiencies of...

2011-07-01

279

40 CFR Table Jj-6 to Subpart Jj of... - Collection Efficiencies of Anaerobic Digesters  

Code of Federal Regulations, 2013 CFR

...Collection Efficiencies of Anaerobic Digesters JJ Table JJ-6 to Subpart JJ of Part 98 Protection of Environment ...Manure Management Pt. 98, Subpt. JJ, Table JJ-6 Table JJ-6 to Subpart JJ of Part 98âCollection Efficiencies of...

2013-07-01

280

Anaerobically digested biosolids odor generation and pathogen indicator regrowth after dewatering  

Microsoft Academic Search

The objective of this research was to investigate whether a preferential stimulation of microorganisms in anaerobically digested biosolids can occur after dewatering and if it can lead to pathogen indicator regrowth and odor generation upon storage. Laboratory incubation simulating biosolids storage indicates that both odorant generation, based on total volatile organic sulfur compound concentrations (TVOSCs) and pathogen indicator regrowth, based

Yen-Chih Chen; Matthew J. Higgins; Steven M. Beightol; Sudhir N. Murthy; William E. Toffey

2011-01-01

281

Conditions Optimization of Anaerobic Digestion Reduction of Septic Tank Nightsoil Sludge Aggrandized by Effective Microorganisms  

Microsoft Academic Search

The effect of temperature, initial pH value and the adding concentration of Effective Microorganisms (EM) on the effect of anaerobic digestion reduction of septic tank nightsoil sludge was studied by means of improving L9 (4 3 ) orthogonal layout. The result shows that all the 3 factors, ie, the temperature, initial pH value and the adding concentration of EM, have

Zhen-Xia Song; Jian-ping Xu

2011-01-01

282

Ozone pre-treatment as improver of PAH removal during anaerobic digestion of urban sludge  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons are ubiquitous persistent pollutants. They may accumulate in sludge during wastewater treatment because of their low biodegradability and their hydrophobic characteristics. Combination of ozonation and anaerobic digestion may be efficient to remove PAHs naturally present in sludge. The objective of this study was to investigate the impact of ozone pre-treatment, with and without surfactant addition, on the

Arodi Bernal-Martinez; Hélène Carrère; Dominique Patureau; Jean-Philippe Delgenès

2007-01-01

283

Integrated treatment of olive oil mill effluents (OME): Study of ozonation coupled with anaerobic digestion  

Microsoft Academic Search

The possibility of coupling a chemical treatment (ozonation) with a biological treatment (anaerobic digestion), is investigated for olive oil mill effluents (OME). Preliminary tests showed that both total phenols and unsaturated lipids are reduced to about 50% in 3h of ozonation and that the total COD remains about unvaried. Nevertheless ozonated OME exhibit in general a longer lag phase and

R. Andreozzi; G. Longo; M. Majone; G. Modesti

1998-01-01

284

Anaerobic digestion of saline creeping wild ryegrass for biogas production and pretreatment of particleboard material  

Microsoft Academic Search

The objective of this research was to develop an integrated process to produce biogas and high-quality particleboard using saline creeping wild ryegrass (CWR), Leymus triticoides through anaerobic digestion (AD). Besides producing biogas, AD also serves as a pretreatment method to remove the wax layer of CWR for improving binding capability and then the residue is used to produce high-quality particleboard.

Yi Zheng; Zhongli Pan; Ruihong Zhang; Hamed M. El-Mashad; Jinming Pan; Bryan M. Jenkins

2009-01-01

285

Enzymatic treatment effects on dewaterability of anaerobically digested biosolids-I: performance evaluations  

Microsoft Academic Search

This paper reports on the ability of an enzymatic pre-treatment to significantly improve the conditioning of wastewater sludges (biosolids) significantly using by a polymeric flocculant. Experiments used anaerobically digested biosolids samples from two different municipal wastewater treatment facilities, and a formulation containing several different hydrolytic enzymes. Samples were incubated at 35°C for 16h then conditioned with the cationic polymer solution.

Azize Ayol

2005-01-01

286

“Weak” ultrasonic pre-treatment on anaerobic digestion of flocculated activated biosolids  

Microsoft Academic Search

This study examined how “weak” ultrasonic pre-treatment affects anaerobic digestion of waste biosolids, treated with a cationic polyelectrolyte flocculant. In relation to pre-treatment, the term “weak” used refers to the fact that the total ultrasonic energy input to biosolids is insufficient to fully disrupt its floc structure or the cell walls, as described in the literature. Methane production potential, floc

C. P Chu; D. J Lee; Bea-Ven Chang; C. S You; J. H Tay

2002-01-01

287

Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable  

Microsoft Academic Search

The potential of microalgae as a source of biofuels and as a technological solution for CO2 fixation is subject to intense academic and industrial research. In the perspective of setting up massive cultures, the management of large quantities of residual biomass and the high amounts of fertilizers must be considered. Anaerobic digestion is a key process that can solve this

Bruno Sialve; Nicolas Bernet; Olivier Bernard

2009-01-01

288

Anaerobic digestion potential for ecological and decentralised sanitation in urban areas.  

PubMed

The potential of anaerobic digestion in ecological and decentralised sanitation has been investigated in this research. Different anaerobic digestion systems were proposed for the treatment of sewage, grey water, black water and faeces. Moreover, mathematical models based on anaerobic digestion model no.1 (ADM1) were developed for determination of a suitable design for each system. For stable performance of an upflow anaerobic sludge blanket (UASB) reactor treating sewage, the model results indicated that optimisation of wastewater conversion to biogas (not COD removal) should be selected for determination of the hydraulic retention time (HRT) of the reactor. For the treatment of sewage or black water in a UASB septic-tank, the model results showed that the sludge removal period was the main parameter for determination of the HRT. At such HRT, both COD removal and wastewater conversion are also optimised. The model results demonstrated that for treatment of faeces in an accumulation (AC) system at temperature > or = 25 degrees C, the filling period of the system should be higher than 60 days. For maximisation of the net biogas production (i.e. reduction of biogas losses as dissolved in the effluent), the separation between grey water, urine and faeces and reduction of water consumption for faeces flushing are required. Furthermore, the faeces and kitchen organic wastes and grey water are digested in, respectively, an AC system and UASB reactor, while the urine is stored. PMID:16841726

Elmitwalli, Tarek; Feng, Yucheng; Behrendt, Joachim; Otterpohl, Ralf

2006-01-01

289

Improvement of anaerobic digester performance by wastewater recirculation through an aerated membrane.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Swine wastewater from an anaerobic digester was recirculated through a silicone hose located in an external aeration chamber to determine its effect on wastewater malodorants and biogas composition. The silicone hose acted as a semipermeable membrane for the passage of small molecules. In the first...

290

Anaerobic digestion of semi-solid organic waste: biogas production and its purification  

Microsoft Academic Search

The main objective of the present experimental investigation was to evaluate the effects of using different bacteria inoculums at identical technical settings on the anaerobic digestion process for the treatment of semi-solid organic waste available from the orthofruit market. As a possible means to improve the biogas production, as well as reduce their pollution potential, the idea of using recycled

G. Lastella; C. Testa; G. Cornacchia; M. Notornicola; F. Voltasio; Vinod Kumar Sharma

2002-01-01

291

Anaerobic co-digestion of livestock wastes with vegetable processing wastes: A statistical analysis  

Microsoft Academic Search

Anaerobic digestion of livestock wastes with carbon rich residues was studied. Swine manure and poultry litter were selected as livestock waste, and vegetable processing waste was selected as the rich carbon source. A Central Composite Design (CCD) and Response Surface Methodology (RSM) were employed in designing experiments and determine individual and interactive effects over methane production and removal of volatile

Beatriz Molinuevo-Salces; María Cruz García-González; Cristina González-Fernández; María José Cuetos; Antonio Morán; Xiomar Gómez

2010-01-01

292

Prospect of anaerobic co-digestion of dairy manure: a review  

Microsoft Academic Search

Dairy manure is an abundant waste in dairy farming and poses handling, storage and disposal challenges. With poor management, dairy manure produces odour, ammonia and releases greenhouse gases that contribute to global warming. Anaerobic digestion (AD) is a means to produce renewable energy and to reduce environmental impacts resulting from improper management of dairy manure. Dairy manure AD suffers from

Eric Atandi; Shafiqur Rahman

2012-01-01

293

Anaerobic digestion of microalgae residues resulting from the biodiesel production process  

Microsoft Academic Search

The recovery of methane from post transesterified microalgae residues has the potential to improve the renewability of the ‘microalgae biomass to biodiesel’ conversion process as well as reduce its cost and environmental impact. This paper deals with the anaerobic digestion of microalgae biomass residues (post transesterification) using semi-continuously fed reactors. The influence of substrate loading concentrations and hydraulic retention times

E. A. Ehimen; Z. F. Sun; C. G. Carrington; E. J. Birch; J. J. Eaton-Rye

2011-01-01

294

Industrial landfill leachate characterization and treatment utilizing anaerobic digestion with methane production  

Microsoft Academic Search

Anaerobic digestion of organic compounds found in an industrial landfill leachate originating from a Superfund site was assessed using mixed methanogenic cultures. Leachate was found to contain a dissolved organic content (DOC) of about 16,000 mg\\/liter, of which 40% was in the form of acetic, propionic and butyric acids. The overall reduction of DOC and the fates of individual volatile

Corbo

1985-01-01

295

ENZYME ADDITION TO THE ANAEROBIC DIGESTION OF MUNICIPAL WASTEWATER PRIMARY SLUDGE  

EPA Science Inventory

The study evaluates the effects of enzyme augmentation on municipal wastewater (MWW) sludge anaerobic digestion. The primary objective was to examine the impact of using enzymes to enhance the degradation of the cellulosic and the oil- and grease-rich sludge fractions. The additi...

296

Test/QA Plan For Verification Of Anaerobic Digester For Energy Production And Pollution Prevention  

EPA Science Inventory

The ETV-ESTE Program conducts third-party verification testing of commercially available technologies that improve the environmental conditions in the U.S. A stakeholder committee of buyers and users of such technologies guided the development of this test on anaerobic digesters...

297

Anaerobic digestion of winery wastewaters derived from different wine making processes  

Microsoft Academic Search

Anaerobic digestion of winery effluents derived from two different wine making processes was compared in a laboratory scale upflow filter. White winery effluents (WWE) were more easily degradable (average soluble COD removal=92%) than red winery effluents (RWE) (average soluble COD removal = 85%). Differences in the reactor microbial populations for the two effluents were also observed. Both aceticlastic and hydrogenotrophic

D. Daffonchio; M. Colombo; G. Origgi; C. Sorlini; V. Andreoni

1998-01-01

298

Anaerobic Digestion. Selected Instructional Activities and References. Instructional Resources Monograph Series.  

ERIC Educational Resources Information Center

|Focusing specifically on the wastewater treatment process of anaerobic digestion, this document identifies instructional and reference materials for use by professionals in the field in the development and implementation of new programs or in the updating of existing programs. It is designed to help trainers, plant operators, educators,…

Townsend, Robert D., Comp.

299

Anaerobic digestion of mechanically treated OFMSW: experimental data on biogas/methane production and residues characterization.  

PubMed

One of the more promising processes for the energetic transformation of waste is the anaerobic digestion of the Organic Fraction of Municipal Solid Waste (OFMSW). An experimental campaign was carried out on three different samples of OFMSW from Waste Separation (WS), one as received and two obtained after mechanical treatment (squeezing): OFMSW slurry (liquid fraction) and OFMSW Waste (residual solid fraction). Anaerobic Biogasification Potential (ABP) and anaerobic digestion tests (AD) were carried out, investigating the effects of inoculum and pH. The OFMSW Waste was also examined to evaluate the possibility to dispose of it in a landfill. Results showed that OFMSW slurry must be diluted and inoculated and that pH control in the start up phase is essential, in order to have significant biogas productions. OFMSW as received did not show a significant biogas production, while OFMSW Waste showed suitable characteristics for landfill disposal, except for Dissolved Organic Carbon. PMID:21763131

Fantozzi, Francesco; Buratti, Cinzia

2011-06-26

300

Effect of endogenous hydrolytic enzymes pretreatment on the anaerobic digestion of sludge.  

PubMed

In this study, the effects of endogenous amylase, endogenous protease and combined amylase/protease pretreatment of sludge were studied to enhance the efficiency of sludge anaerobic digestion. These enzymes were obtained from bacterial fermentation and bacteria were separated from the sludge. All treatments improved sludge solubilization and acidification but had little influence on the floc sizes. In terms of sludge solubilization and acidification amylase was better than protease or mixed enzyme. After 7h endogenous amylase treatment, the supernatant soluble chemical oxygen demand and volatile fatty acids concentration increased by 78.2% and 129.6%, respectively. But, in terms of anaerobic biodegradability, the best result was obtained with combined enzyme treatment, biogas production increased by 23.1% compared to the control after 11days of anaerobic digestion. Scanning electron micrographs observation and particle size analysis revealed that the most important mechanism for the enzyme treatment of sludge might be solubilization of extracellular polymeric substances. PMID:23948225

Yu, Shuyu; Zhang, Guangming; Li, Jianzheng; Zhao, Zhiwei; Kang, Xiaorong

2013-07-26

301

Anaerobic digestion of linear alkyl benzene sulfonates: biodegradation kinetics and metabolite analysis.  

PubMed

In the present work the effect of the alkyl chain length and the position of the sulfophenyl substituent of the linear alkylbenzene sulfonates (LAS) on their anaerobic biodegradability have been investigated. Degradation kinetics of the linear alkyl benzene sulfonates homologues, 2phiC10LAS, 2phiC12LAS and 2phiC14LAS, have been studied. It has been also investigated the effect of the isomer type on the degradation rate of the LAS molecule through the comparative study of the 2phiC10LAS and 5phiC10LAS isomers. Batch anaerobic biodegradation tests were performed using sludge from the anaerobic digester of a wastewater treatment plant as microorganisms source. Ultimate biodegradation was evaluated from the biogas production whereas primary biodegradation was determined by specific analysis of the surfactant. LAS homologues and isomers showed a negligible primary biodegradation under anaerobic conditions. Furthermore, analysis of sulfophenyl carboxilates (SPC) by LC-MS indicated a low and constant level of these LAS degradation metabolites over the test period. These data are consistent with a minimal transformation of the LAS parent molecule in the anaerobic digesters. On the other hand, the addition of the shortest alkyl chain length homologues, decyl and dodecylbenzene sulfonates, reduces the biogas production whereas the most hydrophobic homologue, the tetradecylbenzene sulfonate, enhances the biogas production. This LAS homologue seems to increase the availability of organic compounds sorbed on the anaerobic sludge promoting their biodegradation. PMID:16083770

García, M T; Campos, E; Ribosa, I; Latorre, A; Sánchez-Leal, J

2005-04-07

302

Mesophilic and thermophilic anaerobic digestion of municipal sludge and fat, oil, and grease.  

PubMed

The anaerobic biodegradability of municipal primary sludge, thickened waste activated sludge (TWAS), and fat, oil, and grease (FOG) was assessed using semi-continuous-feed, laboratory-scale anaerobic digesters and compared with the ultimate degradability obtained from 120-day batch digestion at 35 degrees C. In run 1, combined primary sludge and TWAS (40/60%, volatile solids [VS] basis) were fed to digesters operated at mesophilic (35 degrees C) and thermophilic (52 degrees C) temperatures at loading rates of 0.99 and 1.46 g-VS/L x d for primary sludge and TWAS, respectively, and a hydraulic retention time (HRT) of 12 days. The volatile solids destruction values were 25.3 and 30.7% (69 and 83% biodegradable volatile solids destruction) at 35 degrees C and 52 degrees C, respectively. The methane (CH4) yields were 159 and 197 mL at the standard temperature and pressure (STP) conditions of 0 degree C and 1 atm/g-VS added or 632 and 642 mL @ STP/g-VS destroyed at 35 degrees C and 52 degrees C, respectively. In run 2, a mix of primary sludge, TWAS, and FOG (21/31/48%, volatile solids basis) was fed to an acid digester operated at a 1-day HRT, at 35 degrees C, and a loading rate of 52.5 g-VS/L x d. The acid-reactor effluent was fed to two parallel methane-phase reactors operated at an HRT of 12 days and maintained at 35 degrees C and 52 degrees C, respectively. After an initial period of 20 days with near-zero gas production in the acid reactor, biogas production increased and stabilized to approximately 2 mL CH4 @ STP/g-VS added, corresponding to a volatile solids destruction of 0.4%. The acid-phase reactor achieved a 43% decrease in nonsaturated fat and a 16, 26, and 20% increase of soluble COD, volatile fatty acids, and ammonia, respectively. The methane-phase volatile solids destruction values in run 2 were 45 and 51% (85 and 97% biodegradable volatile solids destruction) at 35 degrees C and 52 degrees C, respectively. The methane yields for the methane-phase reactors were 473 and 551 mL @ STP/g-VS added, which is approximately 3 times larger compared with run 1, or 1040 and 1083 mL @ STP/g-VS destroyed, at 35 degrees C and 52 degrees C, respectively. The results indicate that, when co-digesting municipal sludge and FOG, a large FOG organic load fraction could have a profound effect on the methane gas yield. PMID:19472939

Kabouris, John C; Tezel, Ulas; Pavlostathis, Spyros G; Engelmann, Michael; Dulaney, James A; Todd, Allen C; Gillette, Robert A

2009-05-01

303

In situ identification of keratin-hydrolyzing organisms in swine manure inoculated anaerobic digesters.  

PubMed

Feathers, a poultry byproduct, are composed of > 90% keratin which is resistant to degradation during anaerobic digestion. In this study, four 42-L anaerobic digesters inoculated with adapted swine manure were used to investigate feather digestion. Ground feathers were added into two anaerobic digesters for biogas production, whereas another two without feathers were used as negative control. Feather degradation and enhanced methane production were recorded. Keratin-hydrolyzing organisms (KHOs) were visualized in the feather bag fluids after boron-dipyrromethene (BODIPY) fluorescence casein staining. Their abundances correlated (R(2)  = 0.96) to feather digestion rates. A 16S rRNA clone library was constructed for the bacterial populations attached to the feather particles. Ninety-three clones (> 1300 bp) were retrieved and 57 (61%) belonged to class Clostridia in the phylum Firmicutes, while 34 (37%) belonged to class Bacteroidia in the phylum Bacteroidetes. Four oligonucleotide FISH probes were designed for the major Clostridia clusters and used with other FISH probes to identify the KHOs. Probe FIMs1029 hybridized with most (> 80%) of the KHOs. Its targeted sequence perfectly matches that possessed by 10 Clostridia 16S rRNA gene clones belonging to a previously uncharacterized new genus closely related to Alkaliphilus in the subfamily Clostridiaceae 2 of family Clostridiaceae. PMID:22066513

Xia, Yun; Massé, Daniel I; McAllister, Tim A; Beaulieu, Carole; Talbot, Guylaine; Kong, Yunhong; Seviour, Robert

2011-09-15

304

Putting microbes to work in sequence: recent advances in temperature-phased anaerobic digestion processes.  

PubMed

Methane biogas production through anaerobic digestion (or biomethanation) is one of the few technologies that both produce bioenergy and protect the environment. When the focus of anaerobic digestion (AD) is shifted from primarily wastewater treatment to bioenergy production, efficiency and process stability become critical to the economic viability of AD technologies. Temperature-phased anaerobic digestion (TPAD) is a promising process that can significantly enhance both digestion efficiency and process robustness. A TPAD system separates the conventional AD process into two phases, so both phases can be optimized according to their individual functional needs. In the first, thermophilic phase, the often rate-limiting hydrolysis step of polymeric feedstock is accelerated by elevated temperatures, while in the second, mesophilic phase, the fastidious syntrophic acetogens and methanogens are provided with permissive conditions where inhibitions to key guilds (e.g., syntrophic acetogens and methanogens) are attenuated. Although large-scale TPAD systems have not been applied widely, researchers have demonstrated the potential superiority of TPAD systems over single-stage digesters and other AD processes with enhanced VS (volatile solids) and pathogen removal; increased methane yield, process stability, OLR (organic loading rate); shorter HRT (hydraulic retention time); decreased foaming and short-chain fatty acids in effluent. PMID:20709534

Lv, Wen; Schanbacher, Floyd L; Yu, Zhongtang

2010-07-29

305

Characterization and single-stage denitrification anaerobic digestion of spent stream from the hydrolysis-fermentation-combustion process  

NASA Astrophysics Data System (ADS)

The demand for ethanol as an oxygenate and octane booster in automobile fuel is growing. A number of processes are being investigated for conversion of biomass to ethanol. The Hydrolysis-Fermentation-Combustion (HFC) process for fuel ethanol production developed at the University of California Forest Products Laboratory, Richmond, California is at the stage of technology transfer following over two decades of research and development. This study addresses the technology to be used in treatment of spent streams to be discharged from this process. The treatment design combines a single stage denitrification and anaerobic digestion (SSDAD) for the biological treatment of a representative stream from this process. A typical spent stream contained a wide range of soluble organic materials including: unfermented sugars, components of the feedstocks solubilized in the hydrolysis, acid degradation products of carbohydrates, cleavage products of lignin, water-soluble extractives and phenolics, terpenes and other unfermented organic material, and nitrate ion from the nitric acid used as a catalyst in the hydrolysis reaction. Three sets of experiments were conducted in laboratory scale anaerobic digesters. Commonly available anaerobic sludge from local sewage treatment plants was used as a starter seed and was successfully acclimated to the high nitrate substrate leading to enrichment of denitrifiers. Necessary nutrients and trace elements were identified and supplied to satisfy the obligatory requirements of different groups of bacterial groups present. A major finding was the unique role of ammonium hydroxide in controlling pH leading to steady-state operation of the digester. At steady state operation the reduction in COD was 65%, the nitrate reduction was 88% and the nitrite reduction was 100%. Nitrate was reduced to safe nitrogen gas without buildup of any intermediate products. Organic material was converted to useful methane gas and carbon dioxide. The SSDAD system was shown to be effective in treating spent streams having high COD and nitrate concentrations.

Singh, Ramnik

306

Anaerobic thermophilic digestion of sewage sludge with a thickened sludge recycle.  

PubMed

The process of anaerobic thermophilic digestion of municipal wastewater sludge with a recycled part of thickened digested sludge, was studied in semi-continuous laboratory digesters. This modified recycling process resulted in increased solids retention time (SRT) with the same hydraulic retention time (HRT) as compared with traditional digestion without recycling. Increased SRT without increasing of HRT resulted in the enhancement of volatile substance reduction by up to 68% in the reactor with the recycling process compared with 34% in a control conventional reactor. Biogas production was intensified from 0.3 L/g of influent volatile solids (VS) in the control reactor up to 0.35 L/g VS. In addition, the recycling process improved the dewatering properties of digested sludge. PMID:22258668

Vanyushina, A Ya; Nikolaev, Yu A; Agarev, A M; Kevbrina, M V; Kozlov, M N

2012-01-01

307

Increasing microbial activity in thermophilic anaerobic digestion of physicochemical sludge.  

PubMed

Two thermophilic lab-scale reactors of 5 L were operated on a daily fed basis. Digester T1 received raw sludge (control) and digester T2 was fed with raw sludge plus metallic micronutrients and a bacilli additive. Raw sludge was obtained from a municipal chemically enhanced primary treatment plant. The effect of additives was clear on methane production, since on day 50, digester T2 produced 900 ml more methane than T1, an increase of 64%. On day 80, T2 reached twice the production of biogas of T1. Volatile solid removal (% VSR) in T2 increased to 29%; while T1 achieved only 15%. Acetic acid concentration in T2 diminished to 100 mg/L, which related to the higher biogas production. Based on the Mexican biosolids standard, the digested sludge reached Class A biosolids, in both digesters: fecal coliforms were reduced to less than 1000 MPN/gTS; Salmonella spp was totally eliminated and helminth egg counts were lower than one viable egg per gram of total solids. PMID:16939109

Tinajero, A; Noyola, A

2006-01-01

308

A comparative study of ultrasonic pretreatment and an internal recycle for the enhancement of mesophilic anaerobic digestion.  

PubMed

The objective of this study was to investigate the use of ultrasonic energy in an internal recycle and pretreatment mode of operation relative to a conventional mode of mesophilic anaerobic digestion. The primary focus was to determine if using ultrasonics in a pretreatment mode and in an internal recycle line produced changes in performance relative to each other and the control. Using a relatively low-energy sonication system, the data showed that the addition of ultrasonic energy, in either a recycle line or as a pretreatment technology, improved anaerobic digestion efficiency for waste-activated sludge. There was a 13 to 21% increase in biogas yield and an increase in total and volatile solids destruction of 3 to 10.3 additional percentage points, depending on the ultrasonic dose and location. Dewatering of the biosolids following ultrasonic treatment was poorer, as measured by an increase in the optimum polymer conditioning dose. The addition of ultrasonics to the digestion systems generated a more stable biosolids product, with a 2 to 58% reduction in organo-sulfur gas production from dewatered biosolids cakes. PMID:20099624

Muller, Christopher D; Abu-Orf, Mohammad; Blumenschein, Charles D; Novak, John T

2009-12-01

309

Benefits of supplementing an industrial waste anaerobic digester with energy crops for increased biogas production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer This study demonstrates the feasibility of co-digestion food industrial waste with energy crops. Black-Right-Pointing-Pointer Laboratory batch co-digestion led to improved methane yield and carbon to nitrogen ratio as compared to mono-digestion of industrial waste. Black-Right-Pointing-Pointer Co-digestion was also seen as a means of degrading energy crops with nutrients addition as crops are poor in nutrients. Black-Right-Pointing-Pointer Batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. Black-Right-Pointing-Pointer It was concluded that co-digestion led an over all economically viable process and ensured a constant supply of feedstock. - Abstract: Currently, there is increasing competition for waste as feedstock for the growing number of biogas plants. This has led to fluctuation in feedstock supply and biogas plants being operated below maximum capacity. The feasibility of supplementing a protein/lipid-rich industrial waste (pig manure, slaughterhouse waste, food processing and poultry waste) mesophilic anaerobic digester with carbohydrate-rich energy crops (hemp, maize and triticale) was therefore studied in laboratory scale batch and continuous stirred tank reactors (CSTR) with a view to scale-up to a commercial biogas process. Co-digesting industrial waste and crops led to significant improvement in methane yield per ton of feedstock and carbon-to-nitrogen ratio as compared to digestion of the industrial waste alone. Biogas production from crops in combination with industrial waste also avoids the need for micronutrients normally required in crop digestion. The batch co-digestion methane yields were used to predict co-digestion methane yield in full scale operation. This was done based on the ratio of methane yields observed for laboratory batch and CSTR experiments compared to full scale CSTR digestion of industrial waste. The economy of crop-based biogas production is limited under Swedish conditions; therefore, adding crops to existing industrial waste digestion could be a viable alternative to ensure a constant/reliable supply of feedstock to the anaerobic digester.

Nges, Ivo Achu, E-mail: Nges.Ivo_Achu@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden); Escobar, Federico; Fu Xinmei; Bjoernsson, Lovisa [Department of Biotechnology, Lund University, P.O. Box 124, SE 221 00 Lund (Sweden)

2012-01-15

310

Survival of Alternaria alternata during anaerobic digestion of biomass in stirred tank reactors.  

PubMed

The survival of Alternaria alternate during anaerobic digestion was investigated in context of a joint research project. The aim of this project was to estimate the phytosanitary risk of dissemination of pathogens by returning treated biomass as organic fertilizer to arable land. The studies were carried out in lab-scale stirred tank reactors under mesophilic conditions. After insertion of infected plant material into the reactors the influence on the viability of the fungal pathogen was studied concerning exposure time, pretreatment and storage of the digestates for four weeks or six months. The results clearly showed that anaerobic digestion leads to a complete inactivation of A. alternate already after an exposure time of six hours. PMID:23878963

Schleusner, Y; Bandte, M; Gossmann, M; Heiermann, M; Plöchl, M; Büttner, C

2012-01-01

311

Biodegradation of PAH and DEHP micro-pollutants in mesophilic and thermophilic anaerobic sewage sludge digestion.  

PubMed

Anaerobic digestion for the treatment of sludge in wastewater treatment plants has been reported to produce a low organic loaded effluent with an acceptable economic cost. But in the last years, new regulations and the increasing sludge production invite us to find an alternative and/or to improve the process efficiency. Moreover, the use of the effluent as fertilizer in agriculture imposes more restrictions on digestion process product and its micropollutant contents to protect the environment. In this study, a performance of the anaerobic digestion under mesophilic and thermophilic conditions at different hydraulic retention times (HRT) is assessed and the removal efficiencies of two important compounds or family compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Di-2-(Ethyl-Hexyl)-Phthalate, DEHP) are evaluated. A positive effect of thermophilic temperature was observed on both micropollutants' biodegradation. However, HRT effect also had an important role for DEHP and low molecular weighted PAH removal. PMID:16784194

Benabdallah El-Hadj, T; Dosta, J; Mata-Alvarez, J

2006-01-01

312

Model-based predictions of anaerobic digestion of agricultural substrates for biogas production.  

PubMed

A modified Anaerobic Digestion Model No. 1 (ADM1), calibrated on a laboratory digester with a feeding mix of 30% weight of cow manure and 70% weight of corn silage, was implemented, showing its performances of simulation as a decision-making and planning-supporting tool for the anaerobic digestion of agricultural substrates. The virtual fermenter obtained was used to conduct simulations with different feeding compositions and loading rates of cow manure, corn silage, grass silage and rape oil. All simulations were started at the same initial state which was represented by a steady state with an organic loading rate of 2.5 kg ODM/(mdigester3?d). The effects of the different feeding combinations on biogas composition and biogas yield were predicted reasonably, and partly verified with the available literature data. Results demonstrated that the simulations could be helpful for taking decisions on agricultural biogas plant operation or experimental set-ups, if used advisedly. PMID:21974886

Zhou, Haidong; Löffler, Daniel; Kranert, Martin

2011-09-08

313

Anaerobic treatment of lignocellulosic material to co-produce methane and digested fiber for ethanol biorefining.  

PubMed

Five different ratios of corn stover to swine manure were investigated to evaluate the performance of anaerobic digestion and the quality of anaerobically digested fiber (AD fiber) as a feedstock for bioethanol production. The stover-to-manure ratio of 40:60 generated 364L biogas and 797g AD fiber per kg of dry raw feedstock daily. The AD fibers after digestion were pretreated and hydrolyzed to release sugars for ethanol fermentation. The stover-to-manure ratio of 40:60 was able to produce 152g methane and 50g ethanol per kg of dry raw feedstock. The net energy generated from the ratio 40:60 was 5.5MJkg(-1) dry raw feed, which was an 18% increase on net energy output compared to the other ratios and proved to be most beneficial for a biorefinery. PMID:23313688

Maclellan, James; Chen, Rui; Kraemer, Robert; Zhong, Yuan; Liu, Yan; Liao, Wei

2012-12-13

314

Application of mechanical shear in an internal-recycle for the enhancement of mesophilic anaerobic digestion.  

PubMed

A combination of bench- and full-scale studies were conducted to determine the effectiveness of high-intensity mechanical shear in an internal recycle loop to enhance mesophilic anaerobic digestion and the implications of this process for routine operations of a digestion system. During short-term batch digestion (56 hours), a 46% increase in biogas production was observed. However, it was found that the degree of digestion enhancement was sludge-specific, with increases in volatile solids destruction ranging from 16.6 to 110%. A full-scale demonstration showed increased total and volatile solids destruction of 22 and 21% for the primary digester and 17.2 and 11% for the secondary digester, respectively. The data also suggest that increased protein degradation is one of the major mechanisms associated with the observed increases in volatile solids destruction. The full-scale demonstration also determined that shear enhanced digestion can be operated without process upset, based on volatile fatty acid profile and headspace biogas composition (methane and carbon dioxide). Dewatering properties, as measured by polymer demand, deteriorated in the primary digester, but there was improvement in the secondary digester. High-intensity shear does not appear to enhance pathogen reduction based on total and fecal coliform bacterial enumeration. PMID:17469661

Muller, Christopher D; Abu-Orf, Mohammad; Novak, John T

2007-03-01

315

TIME-SETTLEMENT BEHAVIOR OF PROCESSED REFUSE. PART III: ANAEROBIC DIGESTION OF MILLED REFUSE  

EPA Science Inventory

The objectives of this laboratory investigation were to gain an understanding of the decomposition of milled refuse under anaerobic conditions, the rates of decomposition, and the gas production and composition. The rates of decomposition of cellulose and cellulosic materials, ga...

316

Anaerobic Digestion of Red and Chum Salmon Wastes. Final Report.  

National Technical Information Service (NTIS)

This report is on the second and final phase of a project designed to investigate the feasibility of digesting fish wastes to reduce pollution and recover useable oils, solids, and liquids. The first part of the project was a literature search to determin...

G. L. Turner

1982-01-01

317

ANAEROBIC DIGESTION OF ANIMAL WASTE: EFFECT OF MODE OF MIXING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Laboratory-scale digesters were operated to study the effect of mixing (via biogas recirculation, impeller mixing, and slurry recirculation) on biogas production. Three sets of experiments were performed using cow manure slurry feed with either 50, 100, or 150 g/L total solids (TS) concentrations (r...

318

Forward osmosis for concentration of anaerobic digester centrate  

Microsoft Academic Search

The nutrient-rich liquid stream produced during the dewatering of digested biomass (i.e., the centrate) is commonly mixed with the influent raw wastewater at wastewater treatment facilities. This increases the nitrogen and phosphorus loading on biological processes, increases operating costs, and in some cases, results in increased nutrient concentrations in the final effluent. Forward osmosis (FO) is a membrane treatment process

Ryan W. Holloway; Amy E. Childress; Keith E. Dennett; Tzahi Y. Cath

2007-01-01

319

Variation of ADM1 by using temperature-phased anaerobic digestion (TPAD) operation.  

PubMed

The objective of the study was to examine the application of the Anaerobic Digestion Model No. 1 (ADM1) developed by the IWA task group for mathematical modelling of anaerobic process. Lab-scale temperature-phased anaerobic digestion (TPAD) process were operated continuously, and were fed with co-substrate composed of dog food and flour. The model platform implemented in the simulation was a derivative of the ADM1. Sensitivity analysis showed that k(m.process) (maximum specific uptake rate) and K(S.process) (half saturation value) had high sensitivities to model components. Important parameters including maximum uptake rate for propionate utilisers (k(m.pro)) and half saturation constant for acetate utilisers (K(S.ac)) in the thermophilic digester and maximum uptake rate for acetate utilisers (k(m.ac)) in the mesophilic digester were estimated using iterative methods, which optimized the parameters with experimental results. Simulation with estimated parameters showed good agreement with experimental results in the case of methane production, uptake of acetate, soluble chemical oxygen demand (SCOD) and total chemical oxygen demand (TCOD). Under these conditions, the model predicted reasonably well the dynamic behavior of the TPAD process for verifying the model. PMID:19217774

Lee, Myung-Yeol; Suh, Chang-Won; Ahn, Yong-Tae; Shin, Hang-Sik

2009-02-13

320

Microbial community structure and dynamics during anaerobic digestion of various agricultural waste materials.  

PubMed

The influence of the feedstock type on the microbial communities involved in anaerobic digestion was investigated in laboratory-scale biogas reactors fed with different agricultural waste materials. Community composition and dynamics over 2 months of reactors' operation were investigated by amplicon sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Major bacterial taxa belonged to the Clostridia and Bacteroidetes, whereas the archaeal community was dominated by methanogenic archaea of the orders Methanomicrobiales and Methanosarcinales. Correlation analysis revealed that the community composition was mainly influenced by the feedstock type with the exception of a temperature shift from 38 to 55 °C which caused the most pronounced community shifts. Bacterial communities involved in the anaerobic digestion of conventional substrates such as maize silage combined with cattle manure were relatively stable and similar to each other. In contrast, special waste materials such as chicken manure or Jatropha press cake were digested by very distinct and less diverse communities, indicating partial ammonia inhibition or the influence of other inhibiting factors. Anaerobic digestion of chicken manure relied on syntrophic acetate oxidation as the dominant acetate-consuming process due to the inhibition of aceticlastic methanogenesis. Jatropha as substrate led to the enrichment of fiber-degrading specialists belonging to the genera Actinomyces and Fibrobacter. PMID:23624683

Ziganshin, Ayrat M; Liebetrau, Jan; Pröter, Jürgen; Kleinsteuber, Sabine

2013-04-28

321

Hyperspectral imaging techniques applied to the monitoring of wine waste anaerobic digestion process  

NASA Astrophysics Data System (ADS)

An anaerobic digestion process, finalized to biogas production, is characterized by different steps involving the variation of some chemical and physical parameters related to the presence of specific biomasses as: pH, chemical oxygen demand (COD), volatile solids, nitrate (NO3-) and phosphate (PO3-). A correct process characterization requires a periodical sampling of the organic mixture in the reactor and a further analysis of the samples by traditional chemical-physical methods. Such an approach is discontinuous, time-consuming and expensive. A new analytical approach based on hyperspectral imaging in the NIR field (1000 to 1700 nm) is investigated and critically evaluated, with reference to the monitoring of wine waste anaerobic digestion process. The application of the proposed technique was addressed to identify and demonstrate the correlation existing, in terms of quality and reliability of the results, between "classical" chemical-physical parameters and spectral features of the digestate samples. Good results were obtained, ranging from a R2=0.68 and a RMSECV=12.83 mg/l for nitrate to a R2=0.90 and a RMSECV=5495.16 mg O2/l for COD. The proposed approach seems very useful in setting up innovative control strategies allowing for full, continuous control of the anaerobic digestion process.

Serranti, Silvia; Fabbri, Andrea; Bonifazi, Giuseppe

2012-11-01

322

Co-digestion of kitchen waste and fruit-vegetable waste by two-phase anaerobic digestion.  

PubMed

The high salinity and fat contents of kitchen waste (KW) inhibits the effect of two-phase anaerobic digestion system. This research introduces fruit-vegetable waste (FVW) to alleviate the inhibition effect caused by salinity and fat concentrations, and tries to achieve an optimal addition ratio of FVW, an optimal hydraulic remain time (HRT) of acidogenic-phase reactor and methanogenic-phase reactor. A two-phase anaerobic digestion (AD) system was developed to co-dispose KW and FVW. Four sets of experiments were run with different mass proportions between KW and FVW (25-75, 50-50, 75-25, and 100-0% m/m). Considering the biodegradation rate and the acidification degree, the system with 25% KW had the best performance during the acidogenic phase. When the system was run with 50% KW, it not only had the best stability performance but also had a bigger capacity to treat KW than the system with 25% KW. The system with 50% KW was the best ratio in this two-phase AD system. Co-digestion of KW and FVW by two-phase AD is feasible. The addition of FVW can reduce the inhibition effect caused by salinity and fat concentrations, reduce the HRT, and lead to a higher degree of acidification. PMID:23288673

Yang, Yu-Qiang; Shen, Dong-Sheng; Li, Na; Xu, Dong; Long, Yu-Yang; Lu, Xuan-Yu

2013-01-04

323

Two-stage anaerobic digestion enables heavy metal removal.  

PubMed

To fully exploit the environmental benefits of the biogas process, the digestate should be recycled as biofertiliser to agriculture. This practice can however be jeopardized by the presence of unwanted compounds such as heavy metals in the digestate. By using two-stage digestion, where the first stage includes hydrolysis/acidification and liquefaction of the substrate, heavy metals can be transferred to the leachate. From the leachate, metals can then be removed by adsorption. In this study, up to 70% of the Ni, 40% of the Zn and 25% of the Cd present in maize was removed when the leachate from hydrolysis was circulated over a macroporous polyacrylamide column for 6 days. For Cu and Pb, the mobilization in the hydrolytic stage was lower which resulted in a low removal. A more efficient two-stage process with improved substrate hydrolysis would give lower pH and/or longer periods with low pH in the hydrolytic stage. This is likely to increase metal mobilisation, and would open up for an excellent opportunity of heavy metal removal. PMID:18359995

Selling, Robert; Håkansson, Torbjörn; Björnsson, Lovisa

2008-01-01

324

Effect of total solids on fecal coliform regrowth in anaerobically digested biosolids.  

PubMed

Fecal coliform (FC) concentrations in anaerobically digested biosolids can increase during centrifugal dewatering and afterwards in storage of dewatered cake. The immediate increase after centrifugation (reactivation) has been demonstrated to be the revitalization of fecal coliforms that had become non-culturable. The increase during storage (regrowth) has been regarded as a subsequence of reactivated bacteria growing in a favorable environment. In this paper, however, regrowth is demonstrated without preceding reactivation, using intensive laboratory centrifugation to duplicate the levels of regrowth seen in full-scale centrifugation. Higher total solids (TS) levels of the dewatered biosolids lead to greater magnitudes of FC increase. The final TS level appears much more important than the level of shear imposed during centrifugation, based on comparison of different centrifugation/dilution procedures used to obtain similar TS levels. The greater TS levels also reduce methane production, suggesting that methanogens compete with, or inhibit, the fecal coliforms. The addition of bromoethanesulfonate as a methanogen-specific inhibitor decreased the production of methane gas, and also increased the number of fecal coliforms. PMID:18678389

Qi, Yinan; Dentel, Steven K; Herson, Diane S

2008-06-21

325

Sulfate Reduction Relative to Methane Production in High-Rate Anaerobic Digestion: Technical Aspects  

PubMed Central

The effect of different substrates and different levels of sulfate and sulfide on methane production relative to sulfate reduction in high-rate anaerobic digestion was evaluated. Reactors could be acclimated so that sulfate up to a concentration of 5 g of sulfate S per liter did not significantly affect methanogenesis. Higher levels gave inhibition because of salt toxicity. Sulfate reduction was optimal at a relatively low level of sulfate, i.e., 0.5 g of sulfate S per liter, but was also not significantly affected by higher levels. Both acetoclastic and hydrogenotrophic methane-producing bacteria adapted to much higher levels of free H2S than the values reported in the literature (50% inhibition occurred only at free H2S levels of more than 1,000 mg/liter). High levels of free H2S affected the sulfate-reducing bacteria only slightly. Formate and acetate supported the sulfate-reducing bacteria very poorly. In the high-rate reactors studied, intensive H2S formation occurred only when H2 gas or an H2 precursor such as ethanol was supplied.

Isa, Zaid; Grusenmeyer, Stephane; Verstraete, Willy

1986-01-01

326

Ammonia removal from anaerobic digestion effluent of livestock waste using green alga Scenedesmus sp.  

PubMed

The green alga Scenedesmus was investigated for its ability to remove nitrogen from anaerobic digestion effluent possessing high ammonium content and alkalinity in addition to its growth characteristics. Nitrate and ammonium were indistinguishable as a nitrogen source when the ammonium concentration was at normal cultivation levels. Ammonium up to 100ppm NH(4)-N did not inhibit cell growth, but did decrease final cell density by up to 70% at a concentration of 200-500ppm NH(4)-N. Inorganic carbon of alkalinity in the form of bicarbonate was consumed rapidly, in turn causing the attenuation of cell growth. Therefore, maintaining a certain level of inorganic carbon is necessary in order to prolong ammonia removal. A moderate degree of aeration was beneficial to ammonia removal, not only due to the stripping of ammonium to ammonia gas but also due to the stripping of oxygen, which is an inhibitor of regular photosynthesis. Magnesium is easily consumed compared to other metallic components and therefore requires periodic supplementation. Maintaining appropriate levels of alkalinity, Mg, aeration along with optimal an initial NH(4)(+)/cell ratio were all necessary for long-term semi-continuous ammonium removal and cell growth. PMID:20663665

Park, Jongmin; Jin, Hai-Feng; Lim, Byung-Ran; Park, Ki-Young; Lee, Kisay

2010-11-01

327

A comparison of analytical techniques for evaluating food waste degradation by anaerobic digestion.  

PubMed

Organic matter contained in food waste was degraded by anaerobic digestion under mesophilic and thermophilic conditions at two hydraulic retention times. Evolution of the digestion process was followed by thermogravimetry analysis, fluorescence spectroscopy and (1)H nuclear magnetic resonance. All analytical methods suggested that longer retention times might be required for food waste stabilization under mesophilic conditions as compared to thermophilic stabilization. All the analytical methods showed that the stabilization process consisted of two steps, where complex organic molecules were formed during initial stabilization and then digested providing sufficient hydraulic retention time. Longer hydraulic retention times were required for food waste stabilization under mesophilic conditions. Overall, thermal and (1)H NMR analyses of the digestate samples might be recommended if more detailed analysis is required, while fluorescence measurements can be used as a fast screening technique, which provides qualitative assessment of the stabilization process. PMID:19548007

Gómez, X; Cuetos, M J; Tartakovsky, B; Martínez-Núñez, M F; Morán, A

2009-06-23

328

Pilot-scale anaerobic digestion of screenings from wastewater treatment plants.  

PubMed

The anaerobic digestion of screenings from a municipal wastewater treatment plant was studied in a 90 L pilot-scale digester operated at 35 degrees C under semi-continuous conditions. In the first 4 weeks, a dry solids residence time of 28 days was applied, but the installation of inhibitory conditions was observed. Feeding was therefore suspended for 4 weeks to allow the digester to recover from inhibition, and then progressively increased up to a constant load of 6 kg of raw waste per week, corresponding to an average residence time of about 35 days of dry solids. At this stage, biogas production stabilized between 513 and 618 Nl/kg VS(added) per week, with methane contents around 61% v/v. The results of this work thereby supported the feasibility of (co-)digestion as a potential alternative treatment of screenings from municipal wastewater treatment plants. PMID:20655208

Le Hyaric, Ronan; Canler, Jean-Pierre; Barillon, Bruno; Naquin, Pascale; Gourdon, Rémy

2010-07-22

329

Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.  

PubMed

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. PMID:19959355

Dumas, C; Perez, S; Paul, E; Lefebvre, X

2009-12-02

330

Preliminary experimental results of Sewage Sludge (SS) Co-digestion with Palm Oil Mill Effluent (POME) for Enhanced Biogas Production in Laboratory Scale Anaerobic Digester  

NASA Astrophysics Data System (ADS)

An investigation on the feasibility of co-digesting Sewage Sludge with Palm Oil Mill Effluent for enhancing the biogas production and the corresponding effect of the co-digestion substrate ratio on the biogas production has been evaluated. Anaerobic co-digestion of POME with SS was performed at ratios of 100:0, 70:30, 60:40 and 0:100 to find the optimum blend required for enhanced waste digestion and biogas production. Single stage batch digestion was carried out for 12 days in a laboratory scale anaerobic digester. Co-digestion of sludge's at the 70:30 proportion resulted in optimal COD and C: N ratio which subsequently recorded the highest performance with regards to biogas production at 28.1 L's compared to the 1.98 L's of biogas produced from digestion of SS alone. From the results obtained, it is evident that co-digestion of POME and SS is an attractive option to be explored for enhancement of biogas production in anaerobic digesters.

Sivasankari, R.; Kumaran, P.; Normanbhay, Saifuddin; Halim Shamsuddin, Abd

2013-06-01

331

Determination of long chain fatty acids in anaerobic digesters using a rapid non-derivatisation GC-FID method.  

PubMed

A rapid non-derivatisation gas chromatographic (GC) method for quantification of palmitic, stearic and oleic acids was achieved using a flame ionisation detector and a highly polar capillary column at elevated temperature. These long chain fatty acids (LCFA) can accumulate in anaerobic digesters and a simple extraction method was also developed to permit a more rapid sample turn-around time, facilitating more frequent monitoring. The GC method was satisfactory in terms of peak separation, signal response, reproducibility and linearity range. The extraction method achieved recoveries of 103.8, 127.2 and 84.2% for palmitic, stearic and oleic acid respectively. The method was tested on digestate from mesophilic laboratory-scale digesters fed with source-segregated domestic food waste, and showed good repeatability between replicate samples. It was observed that the concentrations of stearic and palmitic acid in digesters routinely supplemented with trace elements were lower in proportion to the applied lipid loading than those without supplementation. PMID:22766861

Jiang, Ying; Zhang, Yue; Banks, Charles J

2012-01-01

332

A hybrid anaerobic membrane bioreactor coupled with online ultrasonic equipment for digestion of waste activated sludge.  

PubMed

Anaerobic membrane bioreactor and online ultrasonic equipment used to enhance membrane filtration were coupled to form a hybrid system (US-AnMBR) designed for long-term digestion of waste activated sludge. The US-AnMBR was operated under volatile solids loading rates of 1.1-3.7 gVS/L·d. After comprehensive studies on digestion performance and membrane fouling control in the US-AnMBR, the final loading rate was determined to be 2.7 gVS/L·d with 51.3% volatile solids destruction. In the US-AnMBR, the improved digestion was due to enhanced sludge disintegration, as indicated by soluble matter comparison in the supernatant and particle size distribution in the digested sludge. Maximum specific methanogenic activity revealed that ultrasound application had no negative effect on anaerobic microorganisms. Furthermore, implementing ultrasound effectively controlled membrane fouling and successfully facilitated membrane bioreactor operation. This lab-scale study demonstrates the potential feasibility and effectiveness of setting up a US-AnMBR system for sludge digestion. PMID:21421308

Xu, Meilan; Wen, Xianghua; Yu, Zhiyong; Li, Yushan; Huang, Xia

2011-02-13

333

Effects of thermal pretreatment on anaerobic digestion of Nannochloropsis salina biomass.  

PubMed

The marine microalga Nannochloropsis salina was investigated as feedstock for anaerobic digestion under batch and semi-continuous conditions for the first time. Biodegradability and methane yield were low under both digestion conditions. Thermal pretreatment prior to anaerobic digestion significantly increased the methane yield from 0.2 to 0.57 m(3) kg VS(-1) under batch conditions and from 0.13 to 0.27 m(3) kg VS(-1) in semi-continuous digestion. Still, the methane yield was limited with semi-continuous feeding due to volatile fatty acid (VFA) accumulation in the digester caused by high ammonium and salt concentrations in the feedstock. Despite VFA accumulation adaption of the microorganisms to the changing conditions and high buffer capacity resulted in steady methane production. A first energy balance considering the required heat for thermal pretreatment revealed significant benefit from the pretreatment. Conversely, the high energy demand for dewatering algal cultures is one major bottleneck for industrial-scale processing of microalgae. PMID:23831893

Schwede, Sebastian; Rehman, Zia-Ur; Gerber, Mandy; Theiss, Carsten; Span, Roland

2013-06-20

334

Detailed study of anaerobic digestion of Spirulina maxima algae biomass  

SciTech Connect

Biomass of the blue-green alga Spirulina maxima was converted to methane using continuous stirred tank digesters with an energy conversion efficiency of 59%. Digesters were operated using once-a-day feeding with a retention time (theta) between 5 and 40 days, volatile solid concentrations (Sto) between 20 and 100 kg VS/cubic m, and temperatures between 15 and 52/sup 0/C. The results indicated a maximum methane yield of 0.35 cubic m (STP)/kg VS added at theta = 30 days and Sto = 20 kg VS/cubic m. Under such conditions, the energy conversion of the algal biomass to methane was 59%. The maximum methane production rate of 0.80 cubic m (STP)/cubic m day was obtained with theta = 20 days and Sto = 100 kg VS/cubic m. The mesophilic condition at 35/sup 0/C produced the maximum methane yield and production rate. The process was stable and characterized by a high production of volatile acids (up to 23,200 mg/l), alkalinity (up to 20,000 mg/l), and ammonia (up to 7000 mg/l), and the high protein content of the biomass produced a well-buffered environment which reduced inhibitory effects. At higher loading rates, the inhibition of methanogenic bacteria was observed, but there was no clear-cut evidence that such a phenomenon was due to nonionized volatile acids or gaseous ammonia. The kinetic analysis using the model proposed by Chen and Hashimoto indicated that the minimum retention time was seven days. The optimum retention time increased gradually from 11 to 16 days with an increase in the initial volatile solid concentration. The kinetic constant K decreased with the improvement in the digester performance and increased in parallel with the ammonia concentration in the culture media. 32 references.

Samson, R.; LeDuy, A.

1986-07-01

335

REACTIVATION AND REGROWTH OF INDICATOR ORGANISMS ASSOCIATED WITH ANAEROBICALLY DIGESTED AND DEWATERED BIOSOLIDS: EPA’S PERSPECTIVE  

EPA Science Inventory

The Water Environment Research Foundation (WERF) recently published a report titled Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bacte...

336

Low vacuum thermochemical conversion of anaerobically digested swine solids.  

PubMed

This work provides data on the production of biochar from the pyrolysis of the solid phase of swine effluents following anaerobic biodigestion. The study involved the low vacuum thermochemical conversion by environmental scanning electron microscope (ESEM) in a thermoregulated hot-stage tungsten SEM. The feedstock was characterized by FTIR, ESEM and energy dispersive X-ray analysis (EDS). The charred feedstock at peak temperatures of 300°C, 400°C, 500°C, 600°C, 700°C, and 1000°C were assessed by SEM and EDS. For each pyrolysis experiment, the exhaust gases were monitored by photoacoustic spectroscopy. SEM/EDS indicated that for increasing peak temperature in low vacuum pyrolysis, the mass losses are greater and the proportion of mineral particles such as P, Ca and Mg in the biochar. Photoacoustic spectroscopy showed that low vacuum pyrolysis is responsible for emissions of toxic gases NH3 and SO2 and radiative trace gases, especially N2O above 600°C. PMID:23582405

Bergier, Ivan; Vinhal-Freitas, Isabel; Guiotoku, Marcela

2013-04-09

337

Two-stage anaerobic digestion of biodegradable municipal solid waste using a rotating drum mesh filter bioreactor and anaerobic filter.  

PubMed

A rotating drum mesh filter bioreactor (RDMFBR) with a 100 microm mesh coupled to an anaerobic filter was used for the anaerobic digestion of biodegradable municipal solid waste (BMW). Duplicate systems were operated for 72 days at an organic loading rate (OLR) of 7.5 g VS l(-1) d(-1). Early in the experiment most of the methane was produced in the 2nd stage. This situation gradually reversed as methanogenesis became established in the 1st stage digester, which eventually produced 86-87% of the total system methane. The total methane production was 0.2 l g(-1) VS(added) with 60-62% volatile solids destruction. No fouling was experienced during the experiment at a transmembrane flux rate of 3.5 l m(-2) h(-1). The system proved to be robust and stably adjusted to a shock loading increase to 15 g VS l(-1) d(-1), although this reduced the overall methane production to 0.15 l g(-1) VS(added). PMID:19406634

Walker, M; Banks, C J; Heaven, S

2009-04-29

338

Anaerobic digestion of tannery waste: Semi-continuous and anaerobic sequencing batch reactor processes  

Microsoft Academic Search

Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37°C or 55°C and an assay of this was shown to be an appropriate screening tool with which to estimate

Gregor D. Zupan?i?; A. Jemec

2010-01-01

339

Influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste*  

PubMed Central

A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 °C to 20 °C suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 °C) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation; (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.

Wu, Man-Chang; Sun, Ke-Wei; Zhang, Yong

2006-01-01

340

Anaerobic digestion of starch-polyvinyl alcohol biopolymer packaging: biodegradability and environmental impact assessment.  

PubMed

The digestibility of a starch-polyvinyl alcohol (PVOH) biopolymer insulated cardboard coolbox was investigated under a defined anaerobic digestion (AD) system with key parameters characterized. Laboratory results were combined with industrial operational data to develop a site-specific life cycle assessment (LCA) model. Inoculated with active bacterial trophic groups, the anaerobic biodegradability of three starch-PVOH biopolymers achieved 58-62%. The LCA modeling showed that the environmental burdens of the starch-PVOH biopolymer packaging under AD conditions on acidification, eutrophication, global warming and photochemical oxidation potential were dominated by atmospheric emissions released from substrate degradation and fuel combustion, whereas energy consumption and infrastructure requirements were the causes of abiotic depletion, ozone depletion and toxic impacts. Nevertheless, for this bio-packaging, AD of the starch-PVOH biopolymer combined with recycling of the cardboard emerged as the environmentally superior option and optimization of the energy utilization system could bring further environmental benefits to the AD process. PMID:22001054

Guo, M; Trzcinski, A P; Stuckey, D C; Murphy, R J

2011-09-22

341

Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Annual report  

SciTech Connect

Municipal solid wastes contain numerous substances of potential environmental concern. While some understanding of the composition of raw municipal waste and its leachate products is available, no information regarding characteristics of solid, liquid and gaseous outputs from anaerobic digestion exists. If centralized anaerobic digestion plants are to be environmentally viable, the characteristics and environmental effects of effluents from these plants must be acceptable. The environmental concerns are particularly acute where ground water supplies are precariously low and the water table is high, South Florida is such a location. A characterization and environmental study was initiated by the Resource Recovery Group on August 1978. The specific objectives are: (1) systematic characterization of solid, liquid and gaseous inputs and outputs; (2) investigations of leaching characteristic of output solid and liquid effluents, and the transport of pollutants to and through ground water systems; and (3) analysis of environmental and process parameters to obtain causal relationships.

Sengupta, S.; Gerrish, H.P.; Wong, K.F.; Nemerow, N.; Daly, E.L. Jr.; Farooq, S.; Chriswell, C.

1980-08-01

342

Kinetics of anaerobic digestion of soft drink wastewater in immobilized cell bioreactors.  

PubMed

A kinetic study of the anaerobic digestion of soft drink wastewater was undertaken, using bioreactors containing various suspended supports (bentonite, zeolite, sepiolite, saponite and polyurethane foam), on to which the microorganisms effecting the purification were immobilized. Assuming the overall anaerobic digestion process conforms to first-order kinetics, the specific rate constants, K0, derived from the reactors with saponite and sepiolite (magnesium silicates) were approximately twice those from bentonite and zeolite (aluminium silicates) and almost five times higher than in the control reactor (without support); the polyurethane support showed an intermediate behaviour. The methanogenic activity increased linearly with COD load, with saponite and sepiolite supports showing the highest values. The average yield coefficient of methane was 325 cm3 CH4 STP g-1 COD and the percentage elimination of COD was 77.8%; these values were not significantly altered by the type of support used. PMID:7764995

Borja, R; Banks, C J

1994-07-01

343

Dry anaerobic digestion of food waste under mesophilic conditions: performance and methanogenic community analysis.  

PubMed

The performance of dry anaerobic digestion (AD) of food waste was investigated under mesophilic conditions and the methanogenic community was investigated using 454 pyrosequencing. Stable dry AD was achieved by hydraulic retention time (HRT) control without the addition of alkali agents. The average CH4 production rate, CH4 content, and volatile solid reduction rate were 2.51±0.17m(3)/m(3)/d, 66±2.1%, and 65.8±1.22%, respectively, at an HRT of 40d. The methanogenic community of the seed sludge experienced a significant reduction in genus diversity from 18 to 4 and a dominant methanogenic shift from hydrogenotrophic to acetoclastic groups after the acclimation under dry condition. Almost all sequences of the dry anaerobic digester were closely related with those of Methanosarcina thermophila with similarity of 96.4-99.1%. The experimental results would serve as useful information to understand the dry AD system. PMID:23347929

Cho, Si-Kyung; Im, Wan-Taek; Kim, Dong-Hoon; Kim, Moon-Hwan; Shin, Hang-Sik; Oh, Sae-Eun

2012-12-29

344

NIR monitoring of ammonia in anaerobic digesters using a diffuse reflectance probe.  

PubMed

The feasibility of using a diffuse reflectance probe attached to a near infrared spectrometer to monitor the total ammonia nitrogen (TAN) content in an anaerobic digester run on cattle manure was investigated; as a previous study has indicated that this probe can be easily attached to an anaerobic digester. Multivariate modelling techniques such as partial least squares regression and interval partial least squares methods were used to build models. Various data pre-treatments were applied to improve the models. The TAN concentrations measured were in the range of 1.5 to 5.5 g/L. An R(2) of 0.91 with an RMSEP of 0.32 was obtained implying that the probe could be used for monitoring and screening purposes. PMID:22438767

Raju, Chitra S; Løkke, Mette Marie; Sutaryo, Sutaryo; Ward, Alastair J; Møller, Henrik B

2012-02-21

345

Enhancement of Taihu blue algae anaerobic digestion efficiency by natural storage.  

PubMed

Taihu blue algae after different storage time from 0 to 60d were anaerobic fermented to evaluate their digestibility and process stability. Results showed that anaerobic digestion (AD) of blue algae under 15d natural storage led to the highest CH4 production of 287.6mLg(-1) VS at inoculum substrate ratio 2.0, demonstrating 36.69% improvement comparing with that from fresh algae. Storage of blue algae led to cell death, microcystins (MCs) release and VS reduction by spontaneous fermentation. However, it also played an important role in removing algal cell wall barrier, pre-hydrolysis and pre-acidification, leading to the improvement in CH4 yield. Closer examination of volatile fatty acids (VFA) variation, VS removal rates and key enzymes change during AD proved short storage time (?15d) of blue algae had higher efficiencies in biodegradation and methanation. Furthermore, AD presented significant biodegradation potential for MCs released from Taihu blue algae. PMID:24128398

Miao, Hengfeng; Lu, Minfeng; Zhao, Mingxing; Huang, Zhenxing; Ren, Hongyan; Yan, Qun; Ruan, Wenquan

2013-09-27

346

A Two-Phased Anaerobic Digestion Process: Concept, Process Failure and Maximum System Loading Rate  

Microsoft Academic Search

This research demonstrated the feasibility of a two-phase anaerobic sludge digestion process. Process failure and maximum system loading capacity were also investigated. Three-dimensional plots of chemical oxygen demand (sol), volatile fatty acids (VFA), and mixed liquor volatile suspended soils (MLVSS) profiles of both reactors during maximization and recovery periods (after failure) were made to evaluate the system feasibility. Hydrolysis-acidification and

P. Fongastitkul; D. S. Mavinic; K. V. Lo

1994-01-01

347

Behavior of cellulose-degrading bacteria in thermophilic anaerobic digestion process.  

PubMed

Previously, we found that the newly isolated Clostridium sp. strain JC3 became the dominant cellulose-degrading bacterium in thermophilic methanogenic sludge. In the present study, the behavior of strain JC3 in the thermophilic anaerobic digestion process was investigated quantitatively by molecular biological techniques. A cellulose-degrading experiment was conducted at 55 degrees C with a 9.5 L of anaerobic baffled reactor having three compartments (Nos. 1, 2, 3). Over 80% of the COD input was converted into methane when 2.5 kgCOD m(-3) d(-1) was loaded for an HRT of 27 days. A FISH probe specific for strain JC3 was applied to sludge samples harvested from the baffled reactor. Consequently, the ratio of JC3 cells to DAPI-stained cells increased from below 0.5% (undetectable) to 9.4% (compartment 1), 13.1% (compartment 2) and 21.6% (compartment 3) at day 84 (2.5 kgCOD m(-3)d(-1)). The strain JC3 cell numbers determined by FISH correlated closely with the cellulose-degrading methanogenic activities of retained sludge. A specific primer set targeting the cellulase gene (cellobiohydrolaseA: cbhA) of strain JC3 was designed and applied to digested sludge for treating solid waste such as coffee grounds, wastepaper, garbage, cellulose and so on. The strain JC3 cell numbers determined by quantitative PCR correlated closely with the cellulose-sludge loading of the thermophilic digester. Strain JC3 is thus important in the anaerobic hydrolysis of cellulose in thermophilic anaerobic digestion processes. PMID:16180412

Syutsubo, K; Nagaya, Y; Sakai, S; Miya, A

2005-01-01

348

Influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste  

Microsoft Academic Search

A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic\\u000a digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55\\u000a °C to 20 °C suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g\\/(L·d) and 15\\u000a d respectively for MOSW

Man-chang Wu; Ke-wei Sun; Yong Zhang

2006-01-01

349

Applications of Anammox based processes to treat anaerobic digester supernatant at room temperature  

Microsoft Academic Search

The supernatant of an anaerobic digester was treated at 20°C in two systems. The first one is a two units configuration, conformed by two sequencing batch reactors (SBR), carrying out partial nitrification and Anammox processes, respectively. Partial nitrification was achieved by granular biomass with a mean diameter of 3mm, operating at a dissolved oxygen concentration of 2.7mg\\/L. The combined system

Jose Vázquez-Padín; Isaac Fernádez; Mónica Figueroa; Anuska Mosquera-Corral; Jose-Luis Campos; Ramón Méndez

2009-01-01

350

Advanced techniques for characterization of organic matter from anaerobically digested grapemarc distillery effluents and amended soils  

Microsoft Academic Search

The effects of grapemarc distillery effluents on the quality of soil organic matter is extremely important to ensure the environmentally-safe\\u000a and agronomically efficient use of these materials as organic amendment. In this work, the effects of the application of untreated\\u000a (UG) and anaerobically digested grapemarc distillery effluents, either added with (AGM) or without mycorrhiza (AG), on soil\\u000a humic acid (HA)

Gennaro Brunetti; Karam Farrag; Cesar Plaza; Nicola Senesi

351

Thermophilic, anaerobic co-digestion of microalgal biomass and cellulose for H2 production.  

PubMed

Microalgal biomass has been a focus in the sustainable energy field, especially biodiesel production. The purpose of this study was to assess the feasibility of treating microalgal biomass and cellulose by anaerobic digestion for H2 production. A microbial consortium, TC60, known to degrade cellulose and other plant polymers, was enriched on a mixture of cellulose and green microalgal biomass of Dunaliella tertiolecta, a marine species, or Chlorella vulgaris, a freshwater species. After five enrichment steps at 60°C, hydrogen yields increased at least 10% under all conditions. Anaerobic digestion of D. tertiolecta and cellulose by TC60 produced 7.7 mmol H2/g volatile solids (VS) which were higher than the levels (2.9-4.2 mmol/g VS) obtained with cellulose and C. vulgaris biomass. Both microalgal slurries contained satellite prokaryotes. The C. vulgaris slurry, without TC60 inoculation, generated H2 levels on par with that of TC60 on cellulose alone. The biomass-fed anaerobic digestion resulted in large shifts in short chain fatty acid concentrations and increased ammonium levels. Growth and H2 production increased when TC60 was grown on a combination of D. tertiolecta and cellulose due to nutrients released from algal cells via lysis. The results indicated that satellite heterotrophs from C. vulgaris produced H2 but the Chlorella biomass was not substantially degraded by TC60. To date, this is the first study to examine H2 production by anaerobic digestion of microalgal biomass. The results indicate that H2 production is feasible but higher yields could be achieved by optimization of the bioprocess conditions including biomass pretreatment. PMID:20878208

Carver, Sarah M; Hulatt, Chris J; Thomas, David N; Tuovinen, Olli H

2010-09-28

352

Anaerobic digestion for global warming control and energy generation—An overview  

Microsoft Academic Search

Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon dioxide – which has been known to be a ‘clean’ fuel since the late 19th century. But a great resurgence of interest in biogas capture – hence methane capture – has occurred in recent years due to the rapidly growing spectre of global warming. Anthropogenic causes

Tasneem Abbasi; S. M. Tauseef; S. A. Abbasi

2012-01-01

353

Thermophilic, anaerobic co-digestion of microalgal biomass and cellulose for H 2 production  

Microsoft Academic Search

Microalgal biomass has been a focus in the sustainable energy field, especially biodiesel production. The purpose of this\\u000a study was to assess the feasibility of treating microalgal biomass and cellulose by anaerobic digestion for H2 production. A microbial consortium, TC60, known to degrade cellulose and other plant polymers, was enriched on a mixture\\u000a of cellulose and green microalgal biomass of

Sarah M. CarverChris; Chris J. Hulatt; David N. Thomas; Olli H. Tuovinen

2011-01-01

354

Industrial applications of the IWA anaerobic digestion model No. 1 (ADM1)  

Microsoft Academic Search

In this paper, the IWA anaerobic digestion model No. 1 (ADM1) is applied to two case studies from contract work on industrial treatment plants. The first was the assessment of acid addition for pH decrease and avoidance of calcium carbonate (CaCO3) precipitation in a paper mill fed UASB. The simulation work found, with a high degree of confidence, that acid

D. J. Batstone; J. Keller

355

Increasing biogas production by thermal (70 °C) sludge pre-treatment prior to thermophilic anaerobic digestion  

Microsoft Academic Search

The objective of this work was to investigate the effect of a low temperature pre-treatment (70°C) on the efficiency of thermophilic anaerobic digestion of primary and secondary waste sludge. Firstly, effect of sludge pre-treatment time (9, 24, 48 and 72h) was evaluated by the increase in volatile dissolved solids (VDSs), volatile fatty acids (VFAs) and biogas production in thermophilic batch

Ivet Ferrer; Sergio Ponsá; Felícitas Vázquez

2008-01-01

356

Peroxidation enhances the biogas production in the anaerobic digestion of biosolids  

Microsoft Academic Search

During the anaerobic digestion of wastewater treatment sludge, commonly called biosolids, an energy rich biogas is formed which is now considered as renewable energy source and widely used for the production of heat and\\/or electricity. Pre-treatment methods, which achieve a transformation of refractory COD into readily available and soluble BOD, have the potential to enhance the biogas-production. This paper studies

Raf Dewil; Lise Appels; Jan Baeyens; Jan Degrève

2007-01-01

357

Escherichia coli inactivation kinetics in anaerobic digestion of dairy manure under moderate, mesophilic and thermophilic temperatures.  

PubMed

Batch anaerobic digestion experiments using dairy manure as feedstocks were performed at moderate (25°C), mesophilic (37°C), and thermophilic (52.5°C) temperatures to understand E. coli, an indicator organism for pathogens, inactivation in dairy manure. Incubation periods at 25, 37, and 52.5°C, were 61, 41, and 28 days respectively. Results were used to develop models for predicting E. coli inactivation and survival in anaerobic digestion. For modeling we used the decay of E. coli at each temperature to calculate the first-order inactivation rate coefficients, and these rates were used to formulate the time - temperature - E. coli survival relationships. We found the inactivation rate coefficient at 52.5°C was 17 and 15 times larger than the inactivation rate coefficients at 25 and 37°C, respectively. Decimal reduction times (D10; time to achieve one log removal) at 25, 37, and 52.5°C, were 9 -10, 7 - 8 days, and < 1 day, respectively. The Arrhenius correlation between inactivation rate coefficients and temperatures over the range 25 -52.5°C was developed to understand the impacts of temperature on E. coli inactivation rate. Using this correlation, the time - temperature - E. coli survival relationships were derived. Besides E. coli inactivation, impacts of temperature on biogas production, methane content, pH change, ORP, and solid reduction were also studied. At higher temperatures, biogas production and methane content was greater than that at low temperatures. While at thermophilic temperature pH was increased, at mesophilic and moderate temperatures pH were reduced over the incubation period. These results can be used to understand pathogen inactivation during anaerobic digestion of dairy manure, and impacts of temperatures on performance of anaerobic digesters treating dairy manure. PMID:21906374

Pandey, Pramod K; Soupir, Michelle L

2011-07-15

358

Post-treatment of effluents from anaerobic digesters by the Anammox process.  

PubMed

The application of the Anammox process was studied under two different approaches for the post-treatment of anaerobic digester supernatants: two independent units, the combined SHARON-Anammox system, performed in a chemostate and a SBR, respectively, and, a single unit system composed by an air pulsing SBR to carry out the CANON process. The technology based on the combination of the SHARON-Anammox process was used to treat the effluent of an anaerobic digester from a fish canning industry. The presence of organic matter in the influent caused fluctuations in the efficiency of the SHARON unit and an optimal nitrite to ammonium ratio was not achieved in this system to feed the Anammox reactor. Nevertheless an overall percentage of nitrogen removal of 40-80% was obtained when the Anammox reactor operated at nitrite limited conditions. In those periods when the effluent from the SHARON unit contained a NO2(-)-N/NH4(+)-N molar ratio higher than 1.3 the Anammox process lost its stability due to nitrite accumulation. The effluent from an anaerobic digester placed at a WWTP was treated by a CANON system operated at room temperature (20-24 degrees C). This system was developed from a nitrifying air pulsing reactor working at limiting dissolved oxygen conditions which was inoculated with Anammox biomass. A quick start-up of the system was observed and the reactor reached a nitrogen removal rate of 0.25 g N/(L d) 40 days after inoculation. The maximum nitrogen removal rate reached 0.5 g N/(L d). These results indicate the feasibility of the treatment of effluents from psychrophilic anaerobic digesters using the Anammox process. PMID:19717899

Vázquez-Padín, J R; Figueroa, M; Fernández, I; Mosquera-Corral, A; Campos, J L; Méndez, R

2009-01-01

359

Designs of anaerobic digesters for producing biogas from municipal solid-waste  

Microsoft Academic Search

The production of biogas is of growing interest as fossil-fuel reserves decline. However, there exists a dearth of literature on the design considerations that would lead to process optimization in the development of anaerobic digesters aimed at creating useful commodities from the ever-abundant municipal solid-waste. Consequently, this paper provides a synthesis of the key issues and analyses concerning the design

A. Hilkiah Igoni; M. J. Ayotamuno; C. L. Eze; S. O. T. Ogaji; S. D. Probert

2008-01-01

360

Inactivation of virus during anaerobic digestion of manure in laboratory scale biogas reactors  

Microsoft Academic Search

Reduction of porcine parvovirus, bovine enterovirus and faecal enterococci were measured in biogas reactors continuously run\\u000a on manure and manure supplemented with household waste at 35°C and 55°C and in batch test run at 70°C. The aim of the experiments\\u000a was to study the sanitation effect of anaerobic digestion and to evaluate the use of faecal enterococci as an indicator

Bente Lund; Vibeke Frøkjær Jensen; Per Have; Birgitte Ahring

1996-01-01

361

Simulation of Chemical Reaction Fronts in Anaerobic Digestion of Solid Waste  

Microsoft Academic Search

A case study for parallelisation of a code for a nonlinear system of evolution equations is presented. It describes the propagation\\u000a of reaction fronts in anaerobic waste digestion. These occur as a consequence of heterogeneous initial distributions of material\\u000a in a landfill site. These heterogeneities can accelerate or slow down the degradation process. The special structure of the\\u000a particular model

Hermann J. Eberl

2003-01-01

362

Correlation between Organic Matter Degradation and the Rheological Performance of Waste Sludge During Anaerobic Digestion  

NASA Astrophysics Data System (ADS)

Anaerobic digestion has demonstrated to be a good possibility to reduce the organic matter contents in waste activated sludge resulting in the effluents treatment. An anaerobic digestion was carried out in a 3.5 L reactor at 35 °C for a period of 20 days. An electronic thermostat controlled the temperature. The reactor was agitated at a rate of 200 rpm. The study of the rheological behavior of the waste activated sludge was done with an Anton Paar™ rheometer model MCR301 with a peltier plate for temperature control. Four-blade vane geometry was used with samples of 37 mL for determining rheological properties. Sampling (two samples) was taken every four days of anaerobic digestion through a peristaltic pump. The samples behavior was characterized by the Herschel-Bulkley model, with R2>0.99 for most cases. In all samples were found an apparent viscosity (?ap) and yield stress (?o) decrement when organic matter content diminishes. This demonstrates a relationship between rheological properties and organic matter concentration (% volatile solids). Also the flow activation energy (Ea) was calculated using the Ahrrenius correlation and samples of waste activated sludge before anaerobic digestion. In this case, samples were run in the rheometer at 200 rpm and a temperature range of 25 to 75 °C with an increment rate of 2 °C per minute. The yield stress observed was in a range of 0.93-0.18 Pa, the apparent viscosity was in a range of 0.0358-0.0010 Pa.s, the reduction of organic matter was in a range of 62.57-58.43% volatile solids and the average flow activation energy was 1.71 Cal.g-mol-1.

Morel, Evangelina S.; Hernández-Hernándes, José A.; Méndez-Contreras, Juan M.; Cantú-Lozano, Denis

2008-07-01

363

Identity and diversity of archaeal communities during anaerobic co-digestion of chicken feathers and other animal wastes.  

PubMed

Digestion of raw feathers in anaerobic digesters inoculated with adapted swine manure, slaughterhouse sludge or dairy manure was investigated using twelve 42-L anaerobic digesters at 25°C. After 120days 74%, 49% and 40% added feathers were converted to methane in swine manure, dairy manure and slaughterhouse sludge anaerobic digesters respectively. 16S rRNA gene clone library analyses identified twenty-one operational taxonomic units containing clone sequences from 5 genera, 5 families and 2 phyla of members of the Archaea from 158 sequenced clones. Fluorescence insitu hybridization revealed that methanogens from the Methanomicrobiales, Methanosarcinales and Methanobacteriales constituted a major fraction (>78%) of these Archaea. A high correlation was seen between the distribution of functional archaeal groups and the NH(3)-N levels of digester mixed liquors. The compositions of archaeal communities fed different substrates were statistically significantly different (P<0.05). PMID:22330600

Xia, Yun; Massé, Daniel I; McAllister, Tim A; Kong, Yunhong; Seviour, Robert; Beaulieu, Carole

2012-01-28

364

[Effect of temperature on methanogenic pathway during household waste anaerobic digestion by stable carbon isotopic signature of CH4].  

PubMed

The methanogenic pathway during anaerobic digestion of household waste was investigated by stable carbon isotopic signature analysis, and testified by the analysis of gas production, leachate characteristics and microbial fluorescence in situ hybridization (FISH) methods. Furthemore, the difference of methanogenic pathway between mesophilic and thermophilic anaerobic digestion was also discussed. Results showed that under mesophilic conditions, the isotopic stable carbon signature of CH4 (delta13 CH4) initially decreased to -69.5 per thousand, indicating that CH4 was produced from CO2 and H2 by hydrogenotrophic methanogens. When active CH4 production phase started, the delta13 CH4 values quickly increased to -23.8 per thousand, which indicated more and more CH4 were formed by aceticlastic methanogens, dominantly the family of Methanosarcinaceae, shown by the FISH results. The delta13 CH4 values decreased successively and ultimately remained at -55 per thousand, indicating that the fraction of aceticlastic methanogenesis finally decreased to a steady level comparative with CO2-derived methanogenesis at the steady slow methane production phase. Under thermophilic conditions, the delta13 CH4 values remained at a level about -70 per thousand, showing that methane were solely produced from CO2 reduction, and acetate syntrophic oxidation happened during the active methane production phase. PMID:19186836

Qu, Xian; He, Pin-Jing; Mazéas, Laurent; Bouchez, Théodore

2008-11-01

365

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Biochemical methane potential decreased by 83% during the two-stage operation. Black-Right-Pointing-Pointer Net energy produced was 84.3 MWh or 46 kWh per million metric tons (Mg). Black-Right-Pointing-Pointer The average removal efficiency of volatile organic compounds (VOCs) was 96-99%. Black-Right-Pointing-Pointer The average removal efficiency of non-methane organic compounds (NMOCs) was 68-99%. Black-Right-Pointing-Pointer The two-stage batch digester proved to be simple to operate and cost-effective. - Abstract: The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3 MWh, or 46 kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.

Yazdani, Ramin, E-mail: ryazdani@sbcglobal.net [Yolo County Planning and Public Works Department, Division of Integrated Waste Management, Woodland, CA 95776 (United States); Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States); Barlaz, Morton A., E-mail: barlaz@eos.ncsu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Augenstein, Don, E-mail: iemdon@aol.com [Institute for Environmental Management, Inc., Palo Alto, CA 94306 (United States); Kayhanian, Masoud, E-mail: mdkayhanian@ucdavis.edu [Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States); Tchobanoglous, George, E-mail: gtchobanoglous@ucdavis.edu [Civil and Environmental Engineering, University of California, One Shields Avenue, Ghausi Hall, Davis, CA 95616 (United States)

2012-05-15

366

Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge.  

PubMed

Microwave (MW) irradiation is one of the new and possible methods used for pretreating the sludge. Following its use in different fields, this MW irradiation method has proved to be more appropriate in the field of environmental research. In this paper, we focused on the effects of MW irradiation at different intensities on solubilization, biodegradation and anaerobic digestion of sludge from the dairy sludge. The changes in the soluble fractions of the organic matter, the biogas yield, the methane content in the biogas were used as control parameters for evaluating the efficiency of the MW pretreatment. Additionally, the energetic efficiency was also examined. In terms of an energetic aspect, the most economical pretreatment of sludge was at 70% intensity for 12 min irradiation time. At this, COD solubilization, SS reduction and biogas production were found to be 18.6%, 14% and 35% higher than the control, respectively. Not only the increase in biogas production was investigated, excluding protein and carbohydrate hydrolysis was also performed successfully by this microwave pretreatment even at low irradiation energy input. Also, experiments were carried out in semi continuous anaerobic digesters, with 3.5L working volume. Combining microwave pretreatment with anaerobic digestion led to 67%, 64% and 57% of SS reduction, VS reduction and biogas production higher than the control, respectively. PMID:23465308

Uma Rani, R; Adish Kumar, S; Kaliappan, S; Yeom, Icktae; Rajesh Banu, J

2013-03-07

367

Phylogenetic and functional diversity of propionate-oxidizing bacteria in an anaerobic digester sludge.  

PubMed

The phylogenetic and functional diversity of syntrophic propionate-oxidizing bacteria (POB) present in an anaerobic digester was investigated by microautoradiography combined with fluorescent in situ hybridization (MAR-FISH) that can directly link 16S rRNA phylogeny with in situ metabolic function. The syntrophic POB community in the anaerobic digester sludge consisted of at least four phylogenetic groups: Syntrophobacter, uncultured short rod Smithella (Smithella sp. SR), uncultured long rod Smithella (Smithella sp. LR), and an unidentified group. The activities of these POB groups were dependent on the propionate concentrations. The uncultured Smithella sp. SR accounted for 52-62% of the total active POB under all the propionate concentrations tested (0.5-15 mM). In contrast, uncultured Smithella sp. LR was active only at lower propionate concentrations and became a dominant active POB at 0.5 mM of propionate. Syntrophobacter accounted for 16-31% of the total active POB above 2.5 mM propionate, whereas the active Syntrophobacter population became low (ca. 6%) at 0.5 mM of propionate. The anaerobic digester was operated in a fill and draw mode, resulting in periodical changes in propionate concentration ranging from 0 to 10 mM. These phylogenetically and functionally diverse, to some extent functionally redundant, active POB communities were dynamically responding to the periodical changes in propionate concentration. PMID:17262205

Ariesyady, Herto Dwi; Ito, Tsukasa; Yoshiguchi, Kazumi; Okabe, Satoshi

2007-01-30

368

Evaluation of a Ca-modified porphyritic andesite for ammonium removal in the anaerobic digestion process.  

PubMed

In this study, a Ca-modified porphyritic andesite (wheat-rice-stone (WRS)) was developed for the anaerobic digestion of ammonium-rich wastes. The Ca-modified WRS was obtained with integrated Ca-salt treatment and calcination. Scanning electron microscope and Brunauer-Emmett-Teller surface area analyses were performed to characterize the Ca-modified WRS, and adsorption isotherms and kinetics were investigated to clarify the adsorption mechanism. The ammonium adsorption process was explained well with a pseudo-second-order kinetic model. The specific surface area of the Ca-modified WRS was determined to be 4.56 sq. m/g, and the maximum NH4(+)-N adsorption capacity was determined to be 45.45 mg/g. These values are improvements over those of natural WRS. The ammonium adsorption capacity remained constant at a pH range from 5.0 to 9.0, which indicates that Ca-modified WRS is a promising material for various applications. The methane-production and chemical oxygen demand-removal aspects of anaerobic digestion were much improved with the addition of Ca-modified WRS. Therefore, Ca-modified WRS could be developed into a viable ammonium adsorbent for the anaerobic digestion of ammonium-rich wastes. PMID:23837319

Wang, Qinghong; Yang, Yingnan; Li, Dawei; Zhang, Zhenya

369

Quantification of viable but nonculturable bacterial pathogens in anaerobic digested sludge.  

PubMed

Enteric bacterial pathogens in sewage sludge easily become viable but nonculturable (VBNC) during anaerobic digestion, which escape detection by standard culture methods and pose a potential health risk. In this study, a method that is combining the standard culture method with the reverse transcription quantitative PCR (RT-qPCR) assay was developed for the quantification of bacterial pathogens in the VBNC state. The cycle threshold (CT) values from RT-qPCR assays were linear to the bacterial number in the range from 10? to 10² most probable number (MPN) per reaction for Escherichia coli (R²=0.9964) and Salmonella typhimurium (R²=0.9938) and from 10? to 10? MPN per reaction for Shigella flexneri (R²=0.997), respectively. Mesophilic anaerobic digestion (MAD) caused the bacterial pathogens in sewage sludge entering into VBNC state with the incidence indexes of 0.01-1.12 for E. coli, 2.48-436.52 for S. typhimurium, and 4.17-6.61 for S. flexneri, respectively. Given different VBNC incidence indexes of bacterial pathogens in sewage sludge by MAD, the quantification results of VBNC pathogens using RT-qPCR could provide an improved evaluation of pathogen inactivation efficiency and biological safety in sludge anaerobic digestion. PMID:22996281

Jiang, Qian; Fu, Bo; Chen, Yan; Wang, Yan; Liu, He

2012-09-21

370

[Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography].  

PubMed

The analysis of seven aliphatic carboxylic acids (formic, acetic, propionic, iso-butyric, n-butyric, iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid, perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection. The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column (TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column (TSKgel Super IC-A/C). Good separation was performed on the TSKgel SCX in shorter retention times. For the TSKgel Super IC-A/C, peak shape of the acids was sharp and symmetrical in spite of longer retention times. In addition, the mutual separation of the acids was good except for iso- and n-butyric acids. The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series), lower concentrations of PFBA and sulfuric acid as eluents, non-suppressed conductivity detection and UV detection at 210 nm. This analysis was applied to anaerobic digestion process waters. The chromatograms with conductivity detection were relatively simpler compared with those of UV detection. The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices. PMID:22799193

Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

2012-04-01

371

Recent development of anaerobic digestion processes for energy recovery from wastes.  

PubMed

Anaerobic digestion leads to the overall gasification of organic wastewaters and wastes, and produces methane and carbon dioxide; this gasification contributes to reducing organic matter and recovering energy from organic carbons. Here, we propose three new processes and demonstrate the effectiveness of each process. By using complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment, the chemical oxygen demand (COD) in wastewater was decreased to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge, cow feces, chicken feces, and food waste without the dilution of the ammonia produced by water or carbon-rich wastes. The hydrogen-methane two-stage fermentation (Hy-Met process), in which the hydrogen produced in the first stage is used for a fuel cell system to generate electricity and the methane produced in the second stage is used to generate heat energy to heat the two reactors and satisfy heat requirements, is useful for the treatment of sugar-rich wastewaters, bread wastes, and biodiesel wastewaters. PMID:17368391

Nishio, Naomichi; Nakashimada, Yutaka

2007-02-01

372

Effect of mass transfer on concentration wave propagation during anaerobic digestion of solid waste.  

PubMed

A distributed model of anaerobic digestion of solid waste was developed to study effects of mass transfer on the rate of propagation of initiation methanogenic area. The diffusion and advection of volatile fatty acids (VFA) and methanogenic biomass were taken into account in the model of a one-dimensional (ID) reactor. It was considered that VFA inhibits both polymer hydrolysis and acetoclastic methanogenesis. This approach allows to view the bioreactor as an active medium that provokes concentration waves from some area of methanogenic initiation (local VFA depression) to the total reactor volume. The model shows that mass transfer-based acceleration of methane production in the reactor is possible when the intensity of VFA utilization in the methanogenic area is sufficient for a complete digestion of the incoming VFA. Otherwise, initiation methanogenic area will be suppressed by increasing concentration of VFA. The obtained results emphasize the importance of considering spatial heterogeneity of the reaction for the analysis of solid anaerobic digestion in bioreactors and landfills. The digestion of solid waste can be optimized by setting the low rate of mass transfer (mixing or leachate recirculation) during lag-phase of the reaction with subsequent increase in the mass transfer rate in parallel with the propagation of methanogenic population. In this case, the rate of concentration waves substantially increases. PMID:12108732

Vavilin, Vasily A; Shchelkanov, Micael Yu; Rytov, Sergey V

2002-05-01

373

Recurrence of fecal coliforms and Salmonella species in biosolids following thermophilic anaerobic digestion.  

PubMed

The U.S. Environmental Protection Agency (U.S. EPA) Part 503 Biosolids Rule requires the fecal coliform (indicator) or Salmonella species (pathogen) density requirements for Class A biosolids to be met at the last point of plant control (truck-loading facility and/or farm for land application). The three Southern Californian wastewater treatment plants in this study produced biosolids by thermophilic anaerobic digestion and all met the Class A limits for both fecal coliforms and Salmonella sp. in the digester outflow biosolids. At two plants, however, a recurrence of fecal coliforms was observed in postdigestion biosolids, which caused exceedance of the Class A limit for fecal coliforms at the truck-loading facility and farm for land application. Comparison of observations at the three plants and further laboratory tests indicated that the recurrence of fecal coliforms can possibly be related to the following combination of factors: (1) incomplete destruction of fecal coliforms during thermophilic anaerobic digestion, (2) contamination of Class A biosolids with fecal coliforms from external sources during postdigestion, (3) a large drop of the postdigestion biosolids temperature to below the maximum for fecal coliform growth, (4) an unknown effect of biosolids dewatering in centrifuges. At Hyperion Treatment Plant (City of Los Angeles, California), fecal coliform recurrence could be prevented by the following: (1) complete conversion to thermophilic operation to exclude contamination by mesophilically digested biosolids and (2) insulation and electrical heat-tracing of postdigestion train for maintaining a high biosolids temperature in postdigestion. PMID:17120460

Iranpour, Reza; Cox, Huub H J

2006-09-01

374

Kinetic study of anaerobic digestion of fruit-processing wastewater in immobilized-cell bioreactors.  

PubMed

The kinetics of the anaerobic digestion of a fruit-processing wastewater [chemical oxygen demand (COD) = 5.1 g/l] were investigated. Laboratory experiments were carried out in bioreactors containing supports of different chemical composition and features, namely bentonite and zeolite (aluminum silicates), sepiolite and saponite (magnesium silicates) and polyurethane foam, to which the microorganisms responsible for the process adhered. The influence of the support medium on the kinetics was compared with a control digester with suspended biomass. Assuming the overall anaerobic digestion process conforms to first-order kinetics, the specific rate constant, K0, was determined for each of the experimental reactors. The average values obtained were: 0.080 h-1 (bentonite); 0.103 h-1 (zeolite); 0.180 h-1 (sepiolite); 0.198 h-1 (saponite); 0.131 h-1 (polyurethane); and 0.037 h-1 (control). The results indicate that the support used to immobilize the micro-organisms had a marked influence on the digestion process; the results were significant at the 95% confidence level. Methanogenic activity increased linearly with COD, with the saponite and sepiolite supports showing the highest values. The yield coefficient of methane was 270 ml of methane (under standard temperature and pressure conditions)/g of COD. The average elimination of COD was 89.5%. PMID:7917066

Borja, R; Banks, C J

1994-08-01

375

Feasibility of anaerobic co-digestion of poultry blood with maize residues.  

PubMed

The potential of anaerobic digestion for the treatment of poultry blood was evaluated in batch assays at laboratory scale and in a mesophilic semi-continuously fed digester. The biodegradability test performed on poultry blood waste showed a strong inhibition. Maize residues were used as co-substrate to overcome inhibition thanks to nitrogen dilution. Under batch operation, increasing the maize concentration from 15% to 70% (volatile solids (VS) basis) provided an increase of biogas from 130±31 to 188±21LCH4/kgVS. In the semi-continuous mesophilic anaerobic digester, the biogas yield was 165±17LCH4/kgVS fed, as a result of strong volatile fatty acid (VFA) accumulation. Although physical modifications of maize particles were observed by Scanning Electron Microscopy (SEM), an incomplete degradation was confirmed from analysis of digestates. Furthermore, Fourier Transform Infrared (FTIR) spectroscopy analysis demonstrated that along with VFA build-up, an accumulation of non-degraded materials took place. PMID:23899572

Cuetos, M J; Gómez, X; Martínez, E J; Fierro, J; Otero, M

2013-07-12

376

Continuously-stirred anaerobic digester to convert organic wastes into biogas: system setup and basic operation.  

PubMed

Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general methodology for constructing, inoculating, operating, and monitoring a CSAD system for the purpose of testing the suitability of a given organic substrate for long-term anaerobic digestion. The construction section of this article will cover building the lab-scale reactor system. The inoculation section will explain how to create an anaerobic environment suitable for seeding with an active methanogenic inoculum. The operating section will cover operation, maintenance, and troubleshooting. The monitoring section will introduce testing protocols using standard analyses. The use of these measures is necessary for reliable experimental assessments of substrate suitability for AD. This protocol should provide greater protection against a common mistake made in AD studies, which is to conclude that reactor failure was caused by the substrate in use, when really it was improper user operation. PMID:22824993

Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

2012-07-13

377

Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake.  

PubMed

Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in <157-2491 ng/L and <157-749 ng/L, respectively. The three studied factors were found to be statistically significant (95% confidence level) in removal of one or more hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively. PMID:23866136

Hamid, Hanna; Eskicioglu, Cigdem

2013-06-05

378

Distributed model of solid waste anaerobic digestion: effects of leachate recirculation and pH adjustment.  

PubMed

A distributed model of solid waste digestion in a 1-D bioreactor with leachate recirculation and pH adjustment was developed to analyze the balance between the rates of polymer hydrolysis/acidogenesis and methanogenesis during the anaerobic digestion of municipal solid waste (MSW). The model was calibrated on previously published experimental data generated in 2-L reactors filled with shredded refuse and operated with leachate recirculation and neutralization. Based on model simulations, both waste degradation and methane production were stimulated when inhibition was prevented rapidly from the start, throughout the reactor volume, by leachate recirculation and neutralization. An optimal strategy to reduce the time needed for solid waste digestion is discussed. PMID:12432582

Vavilin, Vasily A; Rytov, Sergey V; Lokshina, Ljudmila Ya; Pavlostathis, Spyros G; Barlaz, Morton A

2003-01-01

379

High-solids anaerobic digestion: comparison of three pilot scales.  

PubMed

Two experiments were undertaken in three different experimental set-ups in order to compare them: an industrial 21-m3 pilot reactor, a new 40-l laboratory pilot reactor and bmp type plasma bottles. Three consecutive batch dry digestion tests of municipal solid waste were performed under mesophilic conditions with the same feedstock in all vessels. Biogas and methane production at the end of the tests were similar (around 200 m3 CH4STP/tVS) for both pilot reactors and were different from the bottle tests. The dynamics of methane production and VFA accumulation concurred. However, the maximal levels of VFA transitory accumulation varied between reactors and between runs in a same reactor. Ammonia levels were similar in both reactors. These results show that the new reactor accurately imitates the conditions found in the larger one. Adaptation of microorganisms to the waste and operating conditions was also pointed out along the consecutive batches. Thermophilic semi-continuous tests were performed in both reactors with similar conditions. The methane production efficiencies were similar. PMID:19029716

Guendouz, J; Buffière, P; Cacho, J; Carrère, M; Delgenes, J-P

2008-01-01

380

Biokinetic and molecular studies of methanogens in phased anaerobic digestion systems.  

PubMed

The influence of differing operational conditions of two-stage digesters on biokinetic characteristics and communities of methanogenic archaea was evaluated. Operating temperature of each phase influenced the archaeal communities significantly. Also, a strong correlation was observed between community composition and temperature and pH. The maximum specific substrate utilization rates (kmax) of acetoclastic methanogens in the mesophilic and thermophilic 1st phases were 11.4 and 22.0mgCODmgCOD(-1)d(-1), respectively, whereas significantly lower kmax values were estimated for the mesophilic and thermophilic 2nd-phase digesters which were 7.6 and 16.6mgCODmgCOD(-1)d(-1), respectively. It appeared that the biokinetic characteristics of the acetoclastic methanogen communities were reliant on digester loading rates. Also, higher temperature dependency coefficients (?) were observed for the long retention time digesters when compared to the values computed for the 1st-phase digesters. Accordingly, the implementation of two sets of biokinetic parameters for acetoclastic methanogen will improve modeling of phased anaerobic digesters. PMID:24125797

Zamanzadeh, Mirzaman; Parker, Wayne J; Verastegui, Yris; Neufeld, Josh D

2013-09-21

381

FULL-SCALE MESOPHILIC ANAEROBIC CO-DIGESTION OF MUNICIPAL SOLID WASTE AND SEWAGE SLUDGE: METHANE PRODUCTION CHARACTERISTICS  

Microsoft Academic Search

The methane production characteristics of a full scale anaerobic biogas digester processing the putrescible fraction of municipal solid waste (PFMSW) and sewage sludge (SS) were studied by using the operation data of the digester and laboratory experiments. The batch assays indicated methane yields of 300 l kg volatile solids (VS)?1for PFMSW and 220 l kg VS?1for SS. The full scale

Jukka A. Rintala; Kimmo T. Järvinen

1996-01-01

382

Digester gas utilization at West-Southwest Sewage Treatment Works. Final technical report  

SciTech Connect

The physical site and operation of the West Southwest Sewage Treatment Works of the Metropolitan Sanitary District of Greater Chicago are described. Over a billion gallons of sewage is handled each day. Influent is screened to remove large debris, flows through preliminary settling tanks to separate most suspended and floating scum solids, passes through aeration tanks which assist biological decomposition of remaining impurities, and is allowed to settle again before chlorination and/or discharge to the waterway. Sludges collected during the process are mixed with scum and ground screenings, concentrated by gravity or mechanical means, and, in the case pertinent to the subject project, are fed to digestion tanks where the action of anaerobic bacteria generates heat and combustible gas, primarily methane. Digested sludge can be further concentrated and disposed of by application on strip mined land. Gas generated during anaerobic digestion has averaged approximately 2.7 million standard cubic feet per day. Of this amount, 1.7 million SCF per day is used keeping the digesters heated to the proper temperature for the bacteria to thrive. The excess 1.0 million SCF per day is piped from the digesters and burned to supply power for low pressure steam generator.

Not Available

1980-01-01

383

Sulfate reduction, nutrient limitation, and reactor design considerations in anaerobic digesters  

SciTech Connect

Three areas of improvement in anaerobic digestion were investigated: inhibition of sulfate reduction, nutrient limitation, and reactor design. In the anaerobic treatment of wastewaters containing high concentrations of sulfate, hydrogen sulfide, an undesirable end product, is produced by sulfate reducing bacteria (SRB). Research was conducted to evaluate the feasibility of adding SRB-specific biochemical inhibitors to a waste stream as a method of preventing sulfate reduction in continuous anaerobic digesters. Two classes of inhibitory compounds were identified: (1) sulfate analogs and (2) transition metal divalent cations. Molybdate was found to have an immediate inhibitory effect on sulfate reduction, and a delayed effect on other trophic groups. Non-specific inhibition was not caused by a dynamic imbalance due to cessation of fatty acid degradation via sulfate reduction. Transition metals had no effect on sulfate reduction or overall digester performance in high sulfate digesters. The hypothesis that nutrient limitation could be synergistically coupled with the addition of SRB-specific inhibitors was investigated. Recovery of sulfate reduction was slower after molybdate removal from the feed when phosphate was limited as compared with when it was continually added, although this effect may have been an indirect result of non-specific inhibition. Periodic pulse nutrient addition was investigated as a method of (1) reducing cell growth, sludge production and related disposal costs and (2) reducing nutrient addition costs. Sustained waste treatment performance was demonstrated for iron, phosphorus, and nitrogen-free feeds. When withheld nutrients were added in pulses, effective operation could be maintained over long periods. Increasing pulse strength delayed the onset of adverse effects related to nutrient starvation.

Clancy, P.B.

1991-01-01

384

A comparative study of anaerobic digestion of acid cheese whey and dairy manure in a two-stage reactor  

Microsoft Academic Search

The performance of a two-stage, two-phase, unmixed anaerobic digester of 155 l working volume operating on acid cheese whey and dairy manure at various temperatures and hydraulic retention times was investigated. The effect of controlling the pH of the methanogonic stage of cheese whey digestion on the biogas production rate and pollution potential reduction was also investigated. The digester was

A. E. Ghaly

1996-01-01

385

Archaeal community composition affects the function of anaerobic co-digesters in response to organic overload  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Two types of methanogens are necessary to respond successfully to perturbation. Black-Right-Pointing-Pointer Diversity of methanogens correlates with the VFA concentration and methane yield. Black-Right-Pointing-Pointer Aggregates indicate tight spatial relationship between minerals and microorganisms. - Abstract: Microbial community diversity in two thermophilic laboratory-scale and three full-scale anaerobic co-digesters was analysed by genetic profiling based on PCR-amplified partial 16S rRNA genes. In parallel operated laboratory reactors a stepwise increase of the organic loading rate (OLR) resulted in a decrease of methane production and an accumulation of volatile fatty acids (VFAs). However, almost threefold different OLRs were necessary to inhibit the gas production in the reactors. During stable reactor performance, no significant differences in the bacterial community structures were detected, except for in the archaeal communities. Sequencing of archaeal PCR products revealed a dominance of the acetoclastic methanogen Methanosarcina thermophila, while hydrogenotrophic methanogens were of minor importance and differed additionally in their abundance between reactors. As a consequence of the perturbation, changes in bacterial and archaeal populations were observed. After organic overload, hydrogenotrophic methanogens (Methanospirillum hungatei and Methanoculleus receptaculi) became more dominant, especially in the reactor attributed by a higher OLR capacity. In addition, aggregates composed of mineral and organic layers formed during organic overload and indicated tight spatial relationships between minerals and microbial processes that may support de-acidification processes in over-acidified sludge. Comparative analyses of mesophilic stationary phase full-scale reactors additionally indicated a correlation between the diversity of methanogens and the VFA concentration combined with the methane yield. This study demonstrates that the coexistence of two types of methanogens, i.e. hydrogenotrophic and acetoclastic methanogens is necessary to respond successfully to perturbation and leads to stable process performance.

Lerm, S.; Kleyboecker, A. [International Centre for Geothermal Research (ICGR), GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Miethling-Graff, R. [International Centre for Geothermal Research (ICGR), GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Johann Heinrich von Thuenen Institut, Bundesforschungsinstitut fuer Laendliche Raeume, Wald und Fischerei Institut fuer Biodiversitaet, 38116 Braunschweig (Germany); Alawi, M.; Kasina, M.; Liebrich, M. [International Centre for Geothermal Research (ICGR), GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Wuerdemann, H., E-mail: wuerdemann@gfz-potsdam.de [International Centre for Geothermal Research (ICGR), GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany)

2012-03-15

386

Real time monitoring of a biogas digester with gas chromatography, near-infrared spectroscopy, and membrane-inlet mass spectrometry  

Microsoft Academic Search

Four methods of monitoring the anaerobic digestion process were studied at pilot scale. The methods employed were Micro Gas Chromatography (?-GC) and Membrane Inlet Mass Spectrometry (MIMS) for measurements in the gas phase, Near Infrared Spectroscopy (NIRS) and pH in the liquid phase. Micro Gas Chromatography accurately measured H2, CH4, H2S, N2 and O2 in the headspace whereas the MIMS

Alastair James Ward; Emiliano Bruni; Morten K. Lykkegaard; Anders Feilberg; Anders P. S. Adamsen; Anders P. Jensen; Allan K. Poulsen

2011-01-01

387

Comparison of different thickening methods for active biomass recycle for anaerobic digestion of wastewater sludge.  

PubMed

The effect of returning solids to the digester, after one of three thickening processes, on volatile solids reduction (VSR) and gas production was investigated. Three different thickening methods were compared: centrifugation, flotation and gravitational sedimentation. The amount and activity of retained biomass in thickened recycled sludge affected the efficiency of digestion. Semi-continuous laboratory digesters were used to study the influence of thickening processes on thermophilic sludge digestion efficiency. Centrifugation was the most effective method used and caused an increase of VSR from 43% (control) up to 70% and gas generation from 0.40 to 0.44 L g(-1) VS. Flotation and gravitational sedimentation ways of thickening appeared to be less effective if compared with centrifugation. These methods increased VSR only by up to 65 and 51%, respectively and showed no significant increase of gas production. The dewatering capacity of digested sludge, as measured by its specific resistance to filtration, was essentially better for the sludge digested in the reactors with centrifugated and settled recycle. The VS concentration of recycle (g L(-1)), as reflecting the amount of retained biomass, appeared to be one of the most important factors influencing the efficiency of sludge digestion in the recycling technology. PMID:22907466

Vanyushina, A Ya; Agarev, A M; Moyzhes, S I; Nikolaev, Yu A; Kevbrina, M V; Kozlov, M N

2012-01-01

388

Effect of aerobic pretreatment with Aspergillus terreus on the anaerobic digestion of olive-mill wastewater.  

PubMed

A kinetic study was carried out on the anaerobic digestion of olive-mill wastewater (OMW) and OMW that was previously fermented with Aspergillus terreus. The bioreactors used were batch fed and contained saponite as support for the mediating bacteria. The anaerobic digestion process followed first-order kinetics, from which the kinetic constant A was calculated using a non-linear regression. This kinetic parameter was influenced by the pretreatment carried out, and was 3.7 times higher for pretreated OMW than for untreated OMW. The anaerobic processing of pretreated OMW seemingly involved no inhibition phenomena as the biotoxicity and the total phenolic compound content (analysed by HPLC) were reduced by 71.2% and 77.9% respectively as a result of the pretreatment. Finally, the yield coefficient of methane production was 0.345 litres of methane (at standard temperature and pressure)/g of chemical oxygen demand, that is, 23% higher than that provided by untreated wastewater. PMID:7576261

Borja, R; Alba, J; Garrido, S E; Martínez, L; García, M P; Monteoliva, M; Ramos-Cormenzana, A

1995-10-01

389

Evaluation of single vs. staged mesophilic anaerobic digestion of kitchen waste with and without microwave pretreatment.  

PubMed

Effects of single and dual stage (acidogenic-methanogenic) mesophilic anaerobic digestion (AD) of kitchen waste (KW) was evaluated at hydraulic retention times (HRTs) of 20, 15, 12 and 9 d with and without thermal microwave (MW) pretreatment (145 °C). Anaerobic acidification in terms of acid accumulation was superior compared to microaerophilic acidification. Maximum anaerobic acidification of KW was determined to occur with an HRT of 2 d which was then selected for the acidification stage. The dual stage AD system fed with untreated KW produced the maximum biogas and volatile solids (VS) stabilization efficiencies at the shortest HRT of 9 d. Conversely, for free liquid resulting from MW pretreatment of KW the two stage reactor at 20 d HRT produced three fold more methane compared with the untreated free liquid control. However, MW pretreatment and AD of the free liquid fraction only, was not a sustainable treatment option. For KW, staging of the AD process had a greater positive impact on waste stabilization and methane yield compared to single stage reactors or MW pretreatment. KW can be characterized as being a readily biodegradable solid waste; concomitantly it is recommended that digester staging without MW pretreatment be employed to maximize methane yield and production. PMID:23648266

Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin

2013-05-04

390

Application of urea dosing for alkalinity supply during anaerobic digestion of vinasse.  

PubMed

Pushed by demand for renewable energy, the ethanol industry in Brazil is expanding. However, production of 1 m(3) of ethanol generates around 13 m(3) of liquid residues (vinasse), so this expansion results in an increasing need for a more adequate destination of these residues. Nowadays the vinasse is dispersed on the sugar cane fields in the practice of fertirrigation, but anaerobic digestion of this residue may be a better solution, additionally offering an alternative source of energy, able to complement hydroelectric power supply in the dry season. However, when trying to digest vinasse at reduced hydraulic retention times, complications arise from its strong tendency toward acidification, upsetting the fragile balance of transformations normally occurring under anaerobic conditions. For successful operation of an anaerobic treatment process with acceptable hydraulic residence times, increasing alkalinity levels inside the reactor is neces-sary. In the present work we show that pH regulation by means of urea dosing, in spite of the risk posed by ammonia toxicity towards methanogenic biomass, can be a viable alternative to avoid vinasse acidification. The ammonia formed in urea conversion remains in solution, rather than escaping to the biogas, and so its use as fertiliser can offset its cost of application in the process. PMID:23032778

Boncz, M A; Formagini, E L; Santos, L da S; Marques, R D; Paulo, P L

2012-01-01

391

Characterization of a Methanogenic Community within an Algal Fed Anaerobic Digester  

PubMed Central

The microbial diversity and metabolic potential of a methanogenic consortium residing in a 3785-liter anaerobic digester, fed with wastewater algae, was analyzed using 454 pyrosequencing technology. DNA was extracted from anaerobic sludge material and used in metagenomic analysis through PCR amplification of the methyl-coenzyme M reductase ? subunit (mcrA) gene using primer sets ML, MCR, and ME. The majority of annotated mcrA sequences were assigned taxonomically to the genera Methanosaeta in the order Methanosarcinales. Methanogens from the genus Methanosaeta are obligate acetotrophs, suggesting this genus plays a dominant role in methane production from the analyzed fermentation sample. Numerous analyzed sequences within the algae fed anaerobic digester were unclassified and could not be assigned taxonomically. Relative amplicon frequencies were determined for each primer set to determine the utility of each in pyrosequencing. Primer sets ML and MCR performed better quantitatively (representing the large majority of analyzed sequences) than primer set ME. However, each of these primer sets was shown to provide a quantitatively unique community structure, and thus they are of equal importance in mcrA metagenomic analysis.

Ellis, Joshua T.; Tramp, Cody; Sims, Ronald C.; Miller, Charles D.

2012-01-01

392

The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge.  

PubMed

The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods) used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV), rotavirus species A (RVA), norovirus genogroup II (NoV GII) and the hepatitis A virus (HAV) from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR) was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%), RVA, NoV GII (45%) and HAV (18%), indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management. PMID:23440119

Prado, Tatiana; Guilayn, Wilma de Carvalho Pereira Bonet; Gaspar, Ana Maria Coimbra; Miagostovich, Marize Pereira

2013-02-01

393

Modeling a solar-heated anaerobic digester for the developing world using system dynamics  

NASA Astrophysics Data System (ADS)

Much of the developing world lacks access to a dependable source of energy. Agricultural societies such as Mozambique and Papua New Guinea could sustain a reliable energy source through the microbacterial decomposition of animal and crop waste. Anaerobic digestion produces methane, which can be used directly for heating, cooking, and lighting. Adding a solar component to the digester provides a catalyst for bacteria activity, accelerating digestion and increasing biogas production. Using methane decreases the amount of energy expended by collecting and preparing firewood, eliminates hazardous health effects linked to inhalation of particles, and provides energy close to where it is needed. The purpose of this work is two fold: initial efforts focus on the development and validation of a computer-based system dynamics model that combines elements of the anaerobic digestion process in order to predict methane output; second, the model is flexed to explore how the addition of a solar component increases robustness of the design, examines predicted biogas generation as a function of varying input conditions, and determines how best to configure such systems for use in varying developing world environments. Therefore, the central components of the system: solar insolation, waste feedstock, bacteria population and consumption rates, and biogas production are related both conceptually and mathematically through a serious of equations, conversions, and a causal loop and feedback diagram. Given contextual constraints and initial assumptions for both locations, it was determined that solar insolation and subsequent digester temperature control, amount of waste, and extreme weather patterns had the most significant impact on the system as a whole. Model behavior was both reproducible and comparable to that demonstrated in existing experimental systems. This tool can thus be flexed to fit specific contexts within the developing world to improve the standard of living of many people, without significantly altering everyday activities.

Bentley, Johanna Lynn

394

Anaerobic digestion of municipal solid wastes containing variable proportions of waste types.  

PubMed

In many parts of the world there are significant seasonal variations in the production of the main organic wastes, food and green wastes. These waste types display significant differences in their biodegradation rates. This study investigated the options for ensuring process stability during the start up and operation of thermophilic high-solids anaerobic digestion of feedstock composed of varying proportions of food and green wastes. The results show that high seed sludge to feedstock ratio (or low waste loading rate) is necessary for ensuring process pH stability without chemical addition. It was also found that the proportion of green wastes in the feedstock can be used to regulate process pH, particularly when operating at high waste loading rates (or low seed sludge to feedstock ratios). The need for chemical pH correction during start-up and digestion operation decreased with increase in green wastes content of the feedstock. Food wastes were found to be more readily biodegradable leading to higher solids reduction while green wastes brought about pH stability and higher digestate solid content. Combining both waste types in various proportions brought about feedstock with varying buffering capacity and digestion performance. Thus, careful selection of feedstock composition can minimise the need for chemical pH regulation as well as reducing the cost for digestate dewatering for final disposal. PMID:17978442

Akunna, J C; Abdullahi, Y A; Stewart, N A

2007-01-01

395

Anaerobic digestion of maize in coupled leach-bed and anaerobic filter reactors.  

PubMed

The methane potential of a leach bed reactor (LBR) coupled to an anaerobic filter (AF) was assessed using energy maize (Zea mays) as substrate. Four LBRs were used operated as pairs, with and without leachate recirculation, over two feed cycles with retention times of 14 and 28 days. Performance was estimated from the total solids destruction in the LBR, and the volatile fatty acid (VFA) and soluble chemical oxygen demand (SCOD) in the leachate. Overall conversion of fresh substrate added to the combined system was good although the organic loading rate (OLR) was limited. The coupled LBR demonstrated improved hydrolysis performance promoted by good buffering, and the AF showed rapid conversion of leachate SCOD into methane with possible further hydrolysis and acidification. Theoretical estimation of the methane potential showed that between 20-40% of the methane was formed in the LBR and was not captured in this trial. PMID:18957766

Cysneiros, D; Banks, C J; Heaven, S

2008-01-01

396

Anaerobic Digestion of Renewable Biomass: Thermophilic Temperature Governs Methanogen Population Dynamics ? †  

PubMed Central

Beet silage and beet juice were digested continuously as representative energy crops in a thermophilic biogas fermentor for more than 7 years. Fluorescence microscopy of 15 samples covering a period of 650 days revealed that a decrease in temperature from 60°C to 55°C converted a morphologically uniform archaeal population (rods) into a population of methanogens exhibiting different cellular morphologies (rods and coccoid cells). A subsequent temperature increase back to 60°C reestablished the uniform morphology of methanogens observed in the previous 60°C period. In order to verify these observations, representative samples were investigated by amplified rRNA gene restriction analysis (ARDRA) and fluorescence in situ hybridization (FISH). Both methods confirmed the temperature-dependent population shift observed by fluorescence microscopy. Moreover, all samples investigated demonstrated that hydrogenotrophic Methanobacteriales dominated in the fermentor, as 29 of 34 identified operational taxonomic units (OTUs) were assigned to this order. This apparent discrimination of acetoclastic methanogens contradicts common models for anaerobic digestion processes, such as anaerobic digestion model 1 (ADM1), which describes the acetotrophic Euryarchaeota as predominant organisms.

Krakat, Niclas; Westphal, A.; Schmidt, S.; Scherer, P.

2010-01-01

397

Biochar Produced from Anaerobically Digested Fiber Reduces Phosphorus in Dairy Lagoons  

SciTech Connect

This study evaluated the use of biochar produced from anaerobic digester dairy fiber (ADF) to sequester phosphorus (P) from dairy lagoons. The ADF was collected from a plugged flow digester, air-dried to <8% water content, and pelletized. Biochar was produced by slow pyrolysis in a barrel retort. The potential of biochar to reduce P in the anaerobic digester effluent (ADE) was assessed in small-scale filter systems through which the effluent was circulated. Biochar sequestered an average of 381 mg L?1 P from the ADE, and 4 g L?1 ADF was captured as a coating on the biochar. There was an increase of total (1.9 g kg?1), Olsen (763 mg kg?1), and water-extractable P (914 mg kg?1) bound to the biochar after 15 d of filtration. This accounted for a recovery of 32% of the P in the ADE. The recovered P on the biochar was analyzed using 31P nuclear magnetic resonance for P speciation, which confirmed the recovery of inorganic orthophosphate after liquid extraction of the biochar and the presence of inextractable Ca-P in the solid state. The inorganic phosphate was sequestered on the biochar through physical and weak chemical bonding. Results indicate that biochar could be a beneficial component to P reduction in the dairy system.

Streubel, Jason D.; Collins, Harold P.; Tarara, Julie M.; Cochran, Rebecca L.

2012-07-01

398

Discovery and characterization of a new bacterial candidate division by an anaerobic sludge digester metagenomic approach  

PubMed Central

We have constructed a large fosmid library from a mesophilic anaerobic digester and explored its 16S rDNA diversity using a high-density filter DNA–DNA hybridization procedure. We identified a group of 16S rDNA sequences forming a new bacterial lineage named WWE3 (Waste Water of Evry 3). Only one sequence from the public databases shares a sequence identity above 80% with the WWE3 group which hence cannot be affiliated to any known or candidate prokaryotic division. Despite representing a non-negligible fraction (5% of the 16S rDNA sequences) of the bacterial population of this digester, the WWE3 bacteria could not have been retrieved using the conventional 16S rDNA amplification procedure due to their unusual 16S rDNA gene sequence. WWE3 bacteria were detected by polymerase chain reaction (PCR) in various environments (anaerobic digesters, swine lagoon slurries and freshwater biofilms) using newly designed specific PCR primer sets. Fluorescence in situ hybridization (FISH) analysis of sludge samples showed that WWE3 microorganisms are oval-shaped and located deep inside sludge flocs. Detailed phylogenetic analysis showed that WWE3 bacteria form a distinct monophyletic group deeply branching apart from all known bacterial divisions. A new bacterial candidate division status is proposed for this group.

Guermazi, Sonda; Daegelen, Patrick; Dauga, Catherine; Riviere, Delphine; Bouchez, Theodore; Godon, Jean Jacques; Gyapay, Gabor; Sghir, Abdelghani; Pelletier, Eric; Weissenbach, Jean; Le Paslier, Denis

2008-01-01

399

Anaerobic co-digestion of aircraft deicing fluid and municipal wastewater sludge.  

PubMed

At many airports, aircraft deicing fluid and precipitation mix, becoming aircraft deicing runoff having a 5-day biochemical oxygen demand (BOD5) of 10(2) to 10(6) mg/L. Publicly owned treatment works can be used for aerobic biological treatment; however, it may be more economical to use anaerobic digesters to codigest a mixture of aircraft deicing fluid and sludge. The objectives of this investigation were to determine benefits and appropriate propylene glycol aircraft deicing fluid loadings to anaerobic codigesters. Results demonstrate aircraft deicing fluid can be successfully codigested to produce methane; supernatant BOD5 and Kjeldahl nitrogen concentration were not higher in codigesters compared to a conventional digester. Aircraft deicing fluid loadings as high as 1.6 g chemical oxygen demand (COD)/L x d were sustainable in codigesters, whereas system fed only aircraft deicing fluid with nutrients and alkalinity achieved a loading of 0.65 g COD/L x d. The sludge used increased digester alkalinity and provided nitrogen, iron, nickel, cobalt, and biomass required for methanogenesis. The deicer provides organics for increased methane production. PMID:11833757

Zitomer, D; Ferguson, N; McGrady, K; Schilling, J

400

Multi stage high rate biomethanation of poultry litter with self mixed anaerobic digester.  

PubMed

A multi stage high rate biomethanation process with novel self mixed anaerobic digester (SMAD) was developed in the present study to reduce the hydraulic residence time (HRT), increase the volatile solids (VS) loading rate, improve the VS destruction efficiency and enhance the methane yield. Specific design features of SMAD were useful in mixing the digester contents without consuming power and de-alienated the problem of scum formation. In the first phase, poultry litter having 10% total solids (TS) was subjected to high rate biomethanation in multi stage configuration (SMAD-I and II in series with UASB reactor). It was observed that gross VS reduction of 58%, gross methane yield of 0.16 m3 kg(-1) (VS reduced) and VS loading rate of 3.5 kg VS m(-3) day(-1) at HRT of 13 days was obtained. In the second phase SMAD-II was bypassed from the process scheme keeping the other parameters same as in the first phase. The results obtained were not as encouraging as in the first phase. The study showed that multi stage configuration with SMAD design improved the anaerobic digestion process efficiency of poultry litter. PMID:20850298

Rao, A Gangagni; Prakash, S Surya; Joseph, Johny; Reddy, A Rajashekhara; Sarma, P N

2010-08-26

401

Energy recovery from the effluent of plants anaerobically digesting urban solid waste  

NASA Astrophysics Data System (ADS)

The parameters of concentration, time, temperature, and pH to find optimum conditions for enzymatically converting unreacted cellulose in the effluent of an anaerobic digester to glucose for ultimate conversion to methane, and then to project the economics to a 100 tons per day plant was studied. The amount of cellulose hydrolysis for enzyme concentrations from 5 to 1000 CIU/gram of substrate using either filter paper or anaerobically digested municipal solid waste (MSW) reacted over periods of time of from 0 to 72 hours is illustrated. The feasibility of recycling enzymes by ultrafilter capture was studied and it is shown that the recovered enzyme is not denatured by any of several possible enzyme loss mechanisms chemical, physical, or biological. Although rather stable enzyme substrate complexes seem to be formed, various techniques permit a 55% enzyme recovery. Posttreatment of digested MSW by cellulase enzymes produces nearly a threefold increase in biomethanation. The value of the additional methane produced in the process is not sufficient to support the cost of enzymes.

1983-03-01

402

Reducing the environmental impact of methane emissions from dairy farms by anaerobic digestion of cattle waste.  

PubMed

Four dairy cattle farms considered representative of Northern Spain milk production were studied. Cattle waste was characterised and energy consumption in the farms was inventoried. Methane emissions due to slurry/manure management and fuel consumption on the farms were calculated. The possibility of applying anaerobic digestion to the slurry to minimise emissions and of using the biogas produced to replace fossil fuels on the farm was considered. Methane emissions due to slurry management (storage and use as fertiliser) ranged from 34 to 66kg CH(4)cow(-1)year(-1) for dairy cows and from 13 to 25kg CH(4)cow(-1)year(-1) for suckler calves. Cattle on these farms are housed for most of the year, and the contribution from emissions from manure dropped in pastures is insignificant due to the very low methane conversion factors. If anaerobic digestion were implemented on the farms, the potential GHG emissions savings per livestock unit would range from 978 to 1776kg CO(2)eq year(-1), with the main savings due to avoided methane emissions during slurry management. The methane produced would be sufficient to supply digester heating needs (35-55% of the total methane produced) and on-farm fuel energy requirements. PMID:21504844

Marañón, E; Salter, A M; Castrillón, L; Heaven, S; Fernández-Nava, Y

2011-04-19

403

Anaerobic digestion of pressed off leachate from the organic fraction of municipal solid waste.  

PubMed

A highly polluted liquid ("press water") was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of "press water" as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 degrees C. A high methane productivity of 270 m(-3) CH(4)ton(-1) COD(added) or 490 m(-3) CH(4)ton(-1) VS(added) was achieved in the batch experiment. The semi-continuously run laboratory-scale reactor was initially operated at an organic loading rate of 10.7 kg COD m(-3)d(-1). The loading was increased to finally 27.7 kg COD m(-3)d(-1), corresponding to a reduction of the hydraulic retention time from initially 20 to finally 7.7 days. During the digestion, a stable elimination of organic material (measured as COD elimination) of approximately 60% was achieved. Linearly with the increment of the OLR, the volumetric methane production of the reactor increased from 2.6m(3)m(reactor)(-3)d(-1) to 7.1 m(3)m(reactor)(-3)d(-1). The results indicated that "press water" from the organic fraction of municipal solid waste was a suitable substrate for anaerobic digestion which gave a high biogas yield even at very high loading rates. PMID:19825510

Nayono, Satoto E; Winter, Josef; Gallert, Claudia

2009-10-13

404

Application of multi-wavelength fluorometry for on-line monitoring of an anaerobic digestion process.  

PubMed

This work examined the use of multi-wavelength fluorometry for on-line monitoring of an anaerobic digestion process. Experiments were carried out in a laboratory-scale anaerobic digestor fed with either synthetic or agricultural (cheese factory) wastewater. An in-line fiber optic probe installed in the external recirculation loop of the reactor was used to acquire fluorescence spectra with an interval of 5-10 min. The spectra were compared with analytical measurements taken at the same time to develop regression models, which were then used to predict concentrations of chemical oxygen demand, volatile fatty acids, and other key process parameters. A comparison of partial least squares (PLS), nonlinear principal components regression, and step-wise regression models on an independent set of data showed that the PLS model gave the best prediction accuracy. PMID:15276745

Morel, E; Santamaria, K; Perrier, M; Guiot, S R; Tartakovsky, B

405

Influence of bicarbonate buffer on the methanogenetic pathway during thermophilic anaerobic digestion.  

PubMed

To investigate the influence of bicarbonate on the metabolic pathway of methanogenesis, different concentrations of bicarbonate (0-0.2 mol/L) were applied during thermophilic anaerobic digestion of 2.5 and 5 g/L glucose. The stable carbon isotopic results demonstrated that, as the bicarbonate concentration increased, the proportion of total CH4 generated from hydrogenotrophic methanogenesis generally increased. Furthermore, methane production rates and acetate degradation rates were seriously reduced under high levels of bicarbonate (0.15 and 0.2 mol/L). Meanwhile, carbon isotope fractionation was more prominent in treatments with 5 g/L glucose than that of 2.5 g/L glucose. Increased concentrations of bicarbonate altered the dominant methanogens and bacteria and increased the microbial diversity. The inhibitory effects of high concentrations of bicarbonate suggested that bicarbonate should be used cautiously as a buffer salt in anaerobic processes, especially when methanogenetic pathways were studied. PMID:23587826

Lin, Yucheng; Lü, Fan; Shao, Liming; He, Pinjing

2013-03-21

406

Anaerobic digestion of cattail with rumen culture in the presence of heavy metals  

Microsoft Academic Search

The anaerobic digestion of cattail by rumen cultures in the presence of Cu(II), Cd(II) or Cr(VI) was investigated in this study. Three cases were respectively observed for the different metal dosages: promoted cattail degradation and methane production at a low heavy metal concentration, e.g., Cu(II) 2.4mg\\/l, Cd(II) 1.6mg\\/l, Cr(VI) 4.0mg\\/l; reduced cattail degradation efficiency and methane production at a middle

Zheng-Bo Yue; Han-Qing Yu; Zhi-Liang Wang

2007-01-01

407

Prediction of trace compounds in biogas from anaerobic digestion using the MATLAB Neural Network Toolbox  

Microsoft Academic Search

Abstract The outlook,to apply the highly energetic biogas,from,anaerobic,digestion into fuel cells will result in a significantly higher electrical efficiency and,can contribute,to an increase of renewable,energy,production. The practical bottleneck is the fuel cell poisoning,caused,by several gaseous,trace compounds,like hydrogen,sulfide and,ammonia.,Hence artificial neural networks,were developed,to predict these trace compounds.,The experiments,concluded,that ammonia,in biogas,can indeed,be present up to 93 ppm. Hydrogen,sulfide and ammonia,concentrations,in biogas were

David P. B. T. B. Strik; Alexander M. Domnanovich; Loredana Zani; Rudolf Braun; Peter Holubar

2005-01-01

408

Feasibility of anaerobic digested corn stover as biosorbent for heavy metal.  

PubMed

Anaerobic digested (AD) corn stover collected from a lab-scale reactor was used as bioadsorbent to remove the heavy metal in aqueous solution. Effects of contact time and initial heavy metal concentrations on the removal process of Cu(2+) and Cd(2+) were investigated. The maximum adsorption capacities of AD corn stover obtained from Langmuir isotherm models were 83.3 and 50.0mg/g for Cu(2+) and Cd(2+), respectively. Fourier transform infrared spectroscopy (FTIR) was also used to investigate the surface characteristic of raw and heavy metal loaded AD corn stover. PMID:23428799

Wang, Jin; Peng, Shu-chuan; Wan, Zheng-qiang; Yue, Zheng-bo; Wu, Jian; Chen, Tian-hu

2013-02-06

409

Anaerobic digestion of dairy manure influenced by the waste milk from milking operations.  

PubMed

It is not uncommon that a significant amount of milk from milking operations is discharged to manure digesters on dairy farms. To understand the effect of milk on the digester performance, experiments using batch digesters (500-mL flasks) were carried out in this study to co-digest milk and dairy manure at different milk levels for biogas production and pollutant reduction, and a total of 8 treatments were examined [i.e., control (without milk) and 1, 3, 5, 7, 9, 14, and 19% milk additions]. The temperature for all digesters was maintained at 37±0.5°C throughout the experimental period, which was 28 d. The results showed that co-digesting milk with dairy manure could increase biogas productivity, with the percent cumulative biogas volume increased by 5.6, 16.3, 26.5, 40.8, 50.2, 79.9, and 103.8%, as compared with the control, for milk addition of 1, 3, 5, 7, 9, 14, and 19% (vol/vol), respectively. However, the CH(4) content in the biogas decreased slightly as the milk content increased (from 66.5% for the control to 63.5% for 19% milk treatment), implying that the added milk could promote CO(2) production. To avoid that, the milk content in the manure should be controlled below 3%. A linear relationship for the total biogas volume produced with the milk content in the manure was revealed, with a correlation coefficient of 0.99. An improved removal efficiency of chemical oxygen demand was observed for milk-treated digesters. Good linear regressions between the total biogas production and the percent chemical oxygen demand decrease and the substrate carbon/nitrogen ratio were also obtained (correlation coefficients: 0.93 and 0.99, respectively). Besides, co-digestion of dairy manure and milk was found to improve substrate solids breakdown, but had little effect on percent volatile fatty acid decrease. In summary, the waste milk co-digested with dairy manure may not cause negative effects on anaerobic digester performance. PMID:21787914

Wu, X; Dong, C; Yao, W; Zhu, J

2011-08-01

410

Importance of heat transfer in an anaerobic digestion plant in a continental climate context.  

PubMed

Investigation on the sensivity to temperature variations has been achieved on a full-scale experimental dairy wastewater treatment plant including an unheated but insulated upflow anaerobic sludge blanket. A simple steady-state heat transfer model based on energy balance has been designed to forecast the biogas production depending on ambient air and dairy wastewater temperatures variations. Energy balance has been described for any part of the digestion plant. Calculated heat losses were in the same range than observed losses with an uncertainty of about 10%. From the equalization tank to the digester the average heat loss under cold period was close to 10°C due to convection and conduction. Mesophilic conditions are not respected for couples of ambient air and wastewater temperatures ranging respectively from 8-35 to 35-29°C. Technical solutions are suggested to increase the biogas production. PMID:22989635

Merlin, Gérard; Kohler, François; Bouvier, Maele; Lissolo, Thierry; Boileau, Hervé

2012-08-14

411

Case study: the characteristics of the biodegradable waste for the anaerobic digestion plant in Lisbon area.  

PubMed

Taking into account the physical-chemical characteristics of the SC-OFMSW processed at Valorsul's anaerobic digestion plant, the influence of seasonal effects was studied. The waste presents a good quality, with a putrescible content of around 90%. In terms of chemical characteristics, the waste composition is similar to the one referred in the literature. The results show that seasonal variations seem not to affect the SC-OFMSW characteristics. The waste is very soluble and for that reason the solids content in the digester is low (TS in the digestor is 2.8%). The production of biogas is higher than the one predicted in the design operational parameters. Consequently, smaller quantities of compost are produced. PMID:19001708

Vaz, F; Torres, A; Correia, C Neiva

2008-01-01

412

Improved utilization of fish waste by anaerobic digestion following omega-3 fatty acids extraction.  

PubMed

Fish waste is a potentially valuable resource from which high-value products can be obtained. Anaerobic digestion of the original fish waste and the fish sludge remaining after enzymatic pre-treatment to extract fish oil and fish protein hydrolysate was evaluated regarding the potential for methane production. The results showed high biodegradability of both fish sludge and fish waste, giving specific methane yields of 742 and 828 m(3)CH(4)/tons VS added, respectively. However, chemical analysis showed high concentrations of light metals which, together with high fat and protein contents, could be inhibitory to methanogenic bacteria. The feasibility of co-digesting the fish sludge with a carbohydrate-rich residue from crop production was thus investigated, and a full-scale process outlined for converting odorous fish waste to useful products. PMID:22784804

Nges, Ivo Achu; Mbatia, Betty; Björnsson, Lovisa

2012-07-10

413

Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion  

NASA Astrophysics Data System (ADS)

This article focuses on the effects of microwave thermal hydrolysis on sewage sludge anaerobic digestion. Volatile suspended solid (VSS) and COD solubilization of treated sludge were investigated. It was found that the microwave hydrolysis provided a rapid and efficient process to release organics from sludge. The increase of organic dissolution ratio was not obvious when holding time was over 5 min. The effect of the VSS solubilization was mainly dependent on temperature. The highest value of VSS dissolving ratio, 36.4%, was obtained at 170 °C for 30 min. COD dissolving ratio was about 25% at 170 °C. BMP test of excess sludge and mixture of primary and excess sludge proved the increase of methane production. Total biogas production of microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days digestion. For excess sludge, biogas production was 11.1% to 25.9% higher than untreated sludge.

Qiao, W.; Wang, W.; Xun, R.

2008-02-01

414

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions.  

PubMed

With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO(2) emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH(4) production yield (MPY) and VS reduction achieved in this condition were 5.0m(3)/m(3)/d, 0.25 m(3) CH(4)/g COD(added), and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m(3)/m(3)/d, MPY of 0.26 m(3) CH(4)/g COD(added), and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes. PMID:21684733

Kim, Dong-Hoon; Oh, Sae-Eun

415

Biogasification of green and food wastes using anaerobic-phased solids digester system.  

PubMed

The performance of a laboratory-scale anaerobic-phased solid (APS) digester system treating food and green wastes was evaluated at thermophilic condition. The APS system comprised of four hydrolysis digesters and one biogasification reactor. The hydrolysis reactors were operated batchwised at a 12-day retention time, while the biogasification reactor was continuously operated at different hydraulic retention times (HRT). The biogas and methane yields from green waste were determined to be 0.438 and 0.252 L/g volatile solid (VS), respectively, with VS removal of 78%. The biogas and methane yields from food waste were 0.596 and 0.379 L/g VS, respectively, with VS removal of 85%. Hydrogen was produced from hydrolysis reactors during the digestion of food waste. Its content was 30.1% and 8.5% of the biogas produced on the first and second day of digestion, respectively. Hydrogen yield from the whole system was determined to be 0.029 L/g VS representing about 4.9% of the total biogas production from the system. The ratio between the volumes of biogasification and hydrolysis reactors (BR/HR) was found to be a factor that affects the process performance and stability. PMID:21842163

Liu, Guangqing; Zhang, Ruihong; El-Mashad, Hamed M; Dong, Renjie; Liu, Xiaoying

2011-08-13

416

Anaerobic treatment of residual lemon pulp in digesters with semi-continuous feed.  

PubMed

Lemon growing areas in the north of Argentina have industries that produce concentrated juice, peel and essential oil and generate a significant amount of liquid and solid waste as lemon pulp. In Argentina, despite the potential applications that the pulp has as animal feed and human and industrial raw material, only 10% is used for these purposes and the rest is discarded into the environment causing many ecological and economic problems. There is little information in the literature on biotechnologies for the treatment of this industrial waste. This paper shows that lemon pulp is a suitable substrate to be treated by anaerobic digestion. We obtained 86 and 92% reduction of chemical oxygen demand in a digester with a semi-continuous feed and retention time of 10 and 20 days respectively and a productivity of 0.406 g CH(4)/g VS h. Comparative tests showed that pre-digesting the pulp improved the process of digestion and increased biogas generation by 20%. PMID:23202554

Navarro, A R; Lopez, Z; Salguero, J; Maldonado, M C

2013-01-01

417

Potential for methane production from anaerobic co-digestion of swine manure with winery wastewater.  

PubMed

This work examines the methane production potential for the anaerobic co-digestion of swine manure (SM) with winery wastewater (WW). Batch and semi-continuous experiments were carried out under mesophilic conditions. Batch experiments revealed that the highest specific methane yield was 348 mL CH(4)g(-1) COD added, obtained at 85.4% of WW and 0.7 g COD g(-1)VS. Specific methane yield from SM alone was 27 mL CH(4)g(-1) COD added d(-1). Furthermore, specific methane yields were 49, 87 and 107 mL CH(4)g(-1) COD added d(-1) for the reactors co-digesting mixtures with 10% WW, 25% WW and 40% WW, respectively. Co-digestion with 40% WW improved the removal efficiencies up to 52% (TCOD), 132% (SCOD) and 61% (VSS) compared to SM alone. These results suggest that methane can be produced very efficiently by the co-digestion of swine manure with winery wastewater. PMID:21232936

Riaño, B; Molinuevo, B; García-González, M C

2010-12-24

418

Optimization of biological hydrogen production for anaerobic co-digestion of food waste and wastewater biosolids.  

PubMed

Batch anaerobic co-digestion studies were conducted using 21 mixtures (M1-M21) of food waste (FW), primary sludge (PS), and waste activated sludge (WAS) at 37°C and an initial pH of 5.5±0.2. The results showed that co-digestion of FW and sludges had a positive impact on the hydrogen production. The maximum hydrogen yields by co-digestion of FW+PS, FW+WAS, and FW+PS+WAS were achieved at volumetric ratios of 75:25, 75:25, and 80:15:5, respectively, with corresponding optimal COD/N mass ratios of 26, 31 and 30, respectively. Furthermore, the synergistic effect of co-digestion was proven and quantified: the measured hydrogen productions were higher than the sums of the hydrogen productions calculated from each fraction, and the highest percentage increase above the calculated value of 101%, was achieved in the FW+PS+WAS mixture (80:15:5). PMID:23334031

Zhou, Peiqing; Elbeshbishy, Elsayed; Nakhla, George

2012-12-20

419

Anaerobic co-digestion of desugared molasses with cow manure; focusing on sodium and potassium inhibition.  

PubMed

Desugared molasses (DM), a syrup residue from beet-molasses, was investigated for biogas production in both batch and in continuously-stirred tank reactor (CSTR) experiments. DM contained 2-3 times higher concentration of ions than normal molasses, which could inhibit the biogas process. The effect of sodium and potassium concentration on biogas production from manure was also investigated. Fifty percent inhibition occurred at sodium and potassium concentration of 11 and 28 g/L, respectively. The reactor experiments were carried out to investigate the biogas production from DM under different dilutions with water and co-digestion with manure. Stable operation at maximum methane yield of 300 mL-CH4/gVS-added was obtained at a mixture of 5% DM in cow manure. The biogas process was inhibited at DM concentrations higher than 15%. Manure was a good base substrate for co-digestion, and a stable anaerobic digestion could be achieved by co-digesting DM with manure at the concentration below 15% DM. PMID:20951579

Fang, Cheng; Boe, Kanokwan; Angelidaki, Irini

2010-09-26

420

Performance of uasb reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste  

Microsoft Academic Search

This study was conducted to investigate the performance of the upflow anaerobic sludge blanket (UASB) reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. The chemical oxygen demand (COD) removal efficiency was consistently over 96% up to the loading rates of 15.8gCOD\\/ld. The methane production rate increased to 5.5l\\/ld. Of all the COD removed, 92%

H. S Shin; S. K Han; Y. C Song; C. Y Lee

2001-01-01

421

Profile of hydrolases and biogas production during two-stage mesophilic anaerobic digestion of solid potato waste  

Microsoft Academic Search

Two two-stage systems, one consisting of a solid-bed reactor for hydrolysis\\/acidification connected to an upflow anaerobic sludge blanket methanogenic reactor, and the other consisting of a solid-bed reactor connected to a methanogenic reactor packed with wheat straw biofilm carriers, were investigated with regard to hydrolytic enzymes and methane production during mesophilic anaerobic digestion of solid potato waste. Some of the

W. Parawira; M. Murto; J. S. Read; B. Mattiasson

2005-01-01

422

Production of methane from sugar beet silage without manure addition by a single-stage anaerobic digestion process  

Microsoft Academic Search

Single-stage continuous anaerobic conversion of sugar beet silage without manure to methane was investigated in this experimental work, using a laboratory-scale mesophilic anaerobic biogas digester. The sugar beet silage had an extreme low pH of 3.3. The reactor was operated in a hydraulic retention time (HRT) range of between 95 and 15 days, and an organic loading rate (OLR) range

B. Demirel; P. Scherer

2008-01-01

423

Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process.  

PubMed

Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association's Anaerobic Digestion Model N°1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced, providing a plausible explanation of experimental based hypothesis. PMID:23276428

Zonta, Z; Alves, M M; Flotats, X; Palatsi, J

2012-12-19

424

Anaerobic digestion of poplar processing residues for methane production after alkaline treatment.  

PubMed

Poplar processing residues were used for methane production by anaerobic digestion after alkaline treatment and methane production was measured. The highest methane production of 271.9 L/kg volatile solid (VS) was obtained at conditions of 35 g/L and 5.0% NaOH, which was 113.8% higher than non-alkaline treated samples, and 28.9% higher than that of corn straw, which is the conventional anaerobic digestion material in China. The maximal enhancement of 275.5% obtained at conditions of 50 g/L and 7.0% NaOH. Degradation of cellulose, hemicellulose and lignin after treatment increased by 4.0-9.0%, 3.3-6.2%, and 11.1-20.5%, respectively, with NaOH dose ranged from 3.0% to 7.0%. Scanning electron microscopy (SEM), FTIR spectra and Crystallinity measurements showed that the lignocellulosic structures were disrupted by NaOH. The results indicate poplar processing residues might be an efficient substrate for methane production after alkaline treatment. PMID:23524158

Yao, Yiqing; He, Mulan; Ren, Yubing; Ma, Liying; Luo, Yang; Sheng, Hongmei; Xiang, Yun; Zhang, Hua; Li, Qien; An, Lizhe

2013-01-03

425

Comparative performance of mesophilic and thermophilic anaerobic digestion for high-solid sewage sludge.  

PubMed

In local cities, many small sewage and waste treatment facilities are operated independently. To encourage processing by anaerobic digestion at a centralized sewage treatment plant (STP), high-solid sewage sludge is helpful because it reduces the energy and cost required for transporting the sludge from other STPs. Mesophilic and thermophilic anaerobic digestion of sewage sludge at total solids concentrations (TS) of 7.5% and 10% were evaluated using laboratory-scale continuous reactors. Under the mesophilic condition, sewage sludge of 10% TS was successfully treated. Under the thermophilic condition, sewage sludge of 7.5% TS was not successfully treated when the total ammonia concentration was over 2000mgN/L. Batch experiments showed that it takes a few weeks for the methane fermentation activity to recover after being inhibited. The effectiveness of adding easily biodegradable organic matter was confirmed. These results show that high-solid sewage sludge is suitable for small facilities by controlling the operating conditions. PMID:24096284

Hidaka, Taira; Wang, Feng; Togari, Taketo; Uchida, Tsutomu; Suzuki, Yutaka

2013-09-17

426

A critical review on inhibition of anaerobic digestion process by excess ammonia.  

PubMed

Ammonia plays a vital role in the performance and stability of anaerobic digestion (AD) of N-rich organic-feedstock. Several research works were carried-out to study the effect of ammonia on the efficiency of AD of agro-food, industrial and livestock wastes/wastewater. However, excess ammonia remains a critical hitch in AD process. The mechanism of ammonia-inhibition has also been studied and there is no simple strategy available to mitigate ammonia-toxicity, when it exceeds threshold inhibition-level. For successful operation of AD systems at higher ammonia-level, adequate choice of temperature, control of pH and C/N ratio, and utilization of acclimatized-microflora to higher ammonia concentrations may ensure a stable and undisturbed digestion. This review provides a critical summary of earlier and recent research conducted on ammonia-inhibition during the anaerobic degradation of organic substrates, especially, at high ammonia concentrations. This article emphasizes that more profound knowledge on parameters influencing ammonia-inhibition is needed to apply appropriate control strategies. PMID:23835276

Rajagopal, Rajinikanth; Massé, Daniel I; Singh, Gursharan

2013-06-17

427

Inhibitory effects of fruit flavors on methane production during anaerobic digestion.  

PubMed

In order to improve biogas production from fruit wastes, the inhibitory effects of fruit flavors on anaerobic digestion were investigated. Batch anaerobic digestion was performed for 30days using synthetic medium and thermophilic sludge. Three groups of flavor compounds i.e. aldehydes (hexanal, nonanal, and E-2-hexenal), terpenes (car-3-ene, ?-pinene, and myrcene), and alcohol (octanol) at concentration of 0.005%, 0.05%, and 0.5% were examined. All the flavor compounds showed inhibitory effect on methane production. The highest methane reduction was obtained at addition of 0.5% of flavor compounds. For terpenoids, the presence of 0.5% of car-3-ene, myrcene, and ?-pinene reduced 95%, 75%, and 77% of methane production, respectively. For aldehydes, addition of 0.5% concentration resulted in more than 99% methane reduction for hexanal and E-2-hexenal, and 84% methane reduction for nonanal. For alcohol, the presence of 0.5% octanol decreased 99% methane production. PMID:23422220

Wikandari, Rachma; Gudipudi, Sailaja; Pandiyan, Ishwarya; Millati, Ria; Taherzadeh, Mohammad J

2013-02-04

428

Comparison of solid-state to liquid anaerobic digestion of lignocellulosic feedstocks for biogas production.  

PubMed

Lignocellulosic biomass feedstocks (switchgrass, corn stover, wheat straw, yard waste, leaves, waste paper, maple, and pine) were evaluated for methane production under liquid anaerobic digestion (L-AD) and solid-state anaerobic digestion (SS-AD). No significant difference in methane yield between L-AD and SS-AD, except for waste paper and pine, were found. However, the volumetric productivity was 2- to 7-fold greater in the SS-AD system compared with the L-AD system, except for paper. Methane yields from corn stover, wheat straw, and switchgrass were 2-5 times higher than those from yard waste, maple, and pine biomass. Waste paper had a methane yield of only 15 L/kg VS caused by souring during SS-AD due to organic overloading. Pine also had very low biogas yield of 17 L/kg VS, indicating the need for pretreatment prior to SS-AD. The findings of this study can guide future studies to improve the efficiency and stability of SS-AD of lignocellulosic biomass. PMID:22995169

Brown, Dan; Shi, Jian; Li, Yebo

2012-08-22

429

Seasonal variation in chemical properties and degradability by anaerobic digestion of landfill leachate at Benowo in Surabaya, Indonesia.  

PubMed

Seasonal variations in the physical and chemical characteristics of leachate taken from Benowo landfill in Indonesia, including factors likely to inhibit anaerobic digestion, were investigated to determine the impacts on the stability of anaerobic treatment. To evaluate the biodegradability of the leachate, a continuous experiment was conducted by changing the organic loading rate (OLR). Chemical oxygen demand (COD) ranged between 2621 and 16,832 mg L(-1), and COD in the dry season was twice the level in the rainy season owing to reduced rainwater input and significant evaporation. COD, pH, and the concentrations of ammonium ion, and metals in the leachate were within acceptable ranges for decomposition by anaerobic digestion. However, the Na(+) and Cl(-) in the leachate are high enough to inhibit anaerobic digestion. From chemical investigation of leachate at six monitoring wells in Benowo, food waste accumulation and seawater intrusion might cause high salinity in the leachate. In the continuous experiment, COD removal efficiency was maintained at 40% regardless of OLR, suggesting that at least 40% of the leachate contained biodegradable substances. Based on these results, issues surrounding the biological treatment of saline and refractory substances in landfill leachate were discussed. It is suggested that high salinity and refractory substances in the leachate are common issues during the leachate treatment by anaerobic digestion as the implications for similar landfills in other countries around the world. PMID:22813759

Kawai, M; Purwanti, I F; Nagao, N; Slamet, A; Hermana, J; Toda, T

2012-07-17

430

Evaluation of biodegradability of phenol and bisphenol A during mesophilic and thermophilic municipal solid waste anaerobic digestion using 13C-labeled contaminants.  

PubMed

In this paper, the isotopic tracing using (13)C-labeled phenol and bisphenol A was used to study their biodegradation during anaerobic digestion of municipal solid waste. Microcosms were incubated anaerobically at 35 °C (mesophilic conditions) and 55 °C (thermophilic conditions) without steering. A continuous follow-up of the production of biogas (CH(4) and CO(2)), was carried out during 130 d until the establishment of stable methanogenesis. Then (13)C(12)-BPA, and (13)C(6)-phenol were injected in microcosms and the follow-up of their degradation was performed simultaneously by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) and gas chromatography mass spectrometry (GC-MS). Moreover, Carbon-13 Nuclear Magnetic Resonance ((13)C-NMR) Spectroscopy is used in the identification of metabolites. This study proves that the mineralization of phenol to CO(2) and CH(4) occurs during anaerobic digestion both in mesophilic and thermophilic conditions with similar kinetics. In mesophilic condition phenol degradation occurs through the benzoic acid pathway. In thermophilic condition it was not possible to identify the complete metabolic pathway as only acetate was identified as metabolite. Our results suggest that mineralization of phenol under thermophilic condition is instantaneous explaining why metabolites are not observed as they do not accumulate. No biodegradation of BPA was observed. PMID:22985591

Limam, Intissar; Mezni, Mohamed; Guenne, Angéline; Madigou, Céline; Driss, Mohamed Ridha; Bouchez, Théodore; Mazéas, Laurent

2012-09-15

431

Anaerobic digestion and co-digestion of slaughterhouse waste (SHW): influence of heat and pressure pre-treatment in biogas yield.  

PubMed

Mesophilic anaerobic digestion (34+/-1 degrees C) of pre-treated (for 20 min at 133 degrees C, >3 bar) slaughterhouse waste and its co-digestion with the organic fraction of municipal solid waste (OFMSW) have been assessed. Semi-continuously-fed digesters worked with a hydraulic retention time (HRT) of 36 d and organic loading rates (OLR) of 1.2 and 2.6 kg VS(feed)/m(3)d for digestion and co-digestion, respectively, with a previous acclimatization period in all cases. It was not possible to carry out an efficient treatment of hygienized waste, even less so when OFMSW was added as co-substrate. These digesters presented volatile fatty acids (VFA), long chain fatty acids (LCFA) and fats accumulation, leading to instability and inhibition of the degradation process. The aim of applying a heat and pressure pre-treatment to promote splitting of complex lipids and nitrogen-rich waste into simpler and more biodegradable constituents and to enhance biogas production was not successful. These results indicate that the temperature and the high pressure of the pre-treatment applied favoured the formation of compounds that are refractory to anaerobic digestion. The pre-treated slaughterhouse wastes and the final products of these systems were analyzed by FTIR and TGA. These tools verified the existence of complex nitrogen-containing polymers in the final effluents, confirming the formation of refractory compounds during pre-treatment. PMID:20176467

Cuetos, M J; Gómez, X; Otero, M; Morán, A

2010-02-21

432

Prediction of sulfide formation in sewer pressure mains based on the IWA Anaerobic Digestion Model No. 1 (ADM1).  

PubMed

In this paper a new approach is presented to predict sulfide formation in sewers based on the IWA Anaerobic Digestion Model No. 1 (ADM1). Compared with existing models the ADM1 has two crucial advantages. Firstly, it simulates anaerobic digestion processes, of which sulfide formation is the final step. Secondly, it uses a more detailed description of the waste water composition. In order to obtain reliable data for calculation an experimental set-up for measuring the Oxygen Uptake Rate (OUR) is used. An implementation of sulfide formation processes into the model matrix is proposed. PMID:16459772

Freudenthal, K; Koglatis, J; Otterpohl, R; Behrendt, J

2005-01-01

433

Influence of heavy metal supplementation on specific methanogenic activity and microbial communities detected in batch anaerobic digesters.  

PubMed

Natural and modified zeolites (0.5-1.0 mm) from the Tasajera deposit in Cuba were used to enhance the anaerobic digestion process of synthetic substrates. Natural zeolites were modified by ionic exchange and by adsorption with nickel, cobalt and magnesium. The experiments were carried out by using an inoculum from a full-scale anaerobic reactor treating winery wastewater. Modified natural zeolites not only enhanced the anaerobic digestion process, but also increased the specific methanogenic activity (SMA) of the sludges. The textural and chemical surface characteristics of the modified zeolites were related to the process performance, volatile fatty acid (VFA) production and microbial communities found in the digesters. For the selected dose of modified zeolites [0.05 g/g of volatile suspended solids (VSS)], the lowest concentration was found for cobalt followed by nickel and magnesium. Based on the analyses of anaerobic biofilms, the heavy metal incorporated into the zeolite was shown to have a great influence on the predominance of species. For example, the presence of nickel and cobalt favoured Methanosaeta, while at the same dose magnesic zeolite stimulated the presence of Methanosarcina and sulfate-reducing bacteria (SRB). In digesters with modified zeolites and metal supplementations the values of SMA were higher than those obtained in the control and natural zeolite digesters. PMID:20658410

Milan, Z; Montalvo, S; Ruiz-Tagle, N; Urrutia, H; Chamy, R; Sanchez, E; Borja, R

2010-09-01

434

Conductive heating and microwave hydrolysis under identical heating profiles for advanced anaerobic digestion of municipal sludge.  

PubMed

Microwave (2.45 GHz, 1200 W) and conventional heating (custom pressure vessel) pretreatments were applied to dewatered municipal waste sludge (18% total solids) using identical heating profiles that span a wide range of temperatures (80-160 °C). Fourteen lab-scale semi-continuous digesters were set up to optimize the energy (methane) output and sludge retention time (SRT) requirements of untreated (control) and thermally pretreated anaerobic digesters operated under mesophilic and thermophilic temperatures. Both pretreatment methods indicated that in the pretreatment range of 80-160 °C, temperature was a statistically significant factor (p-value < 0.05) for increasing solubilization of chemical oxygen demand and biopolymers (proteins, sugars, humic acids) of the waste sludge. However, the type of pretreatment method, i.e. microwave versus conventional heating, had no statistically significant effect (p-value >0.05) on sludge solubilization. With the exception of the control digesters at a 5-d SRT, all control and pretreated digesters achieved steady state at all three SRTs, corresponding to volumetric organic loading rates of 1.74-6.96 g chemical oxygen demand/L/d. At an SRT of 5 d, both mesophilic and thermophilic controls stopped producing biogas after 20 d of operation with total volatile fatty acids concentrations exceeding 1818 mg/L at pH <5.64 for mesophilic and 2853 mg/L at pH <7.02 for thermophilic controls, while the pretreated digesters continued producing biogas. Furthermore, relative (to control) organic removal efficiencies dramatically increased as SRT was shortened from 20 to 10 and then 5 d, indicating that the control digesters were challenged as the organic loading rate was increased. Energy analysis showed that, at an elevated temperature of 160 °C, the amount of methane recovered was not enough to compensate for the energy input. Among the digesters with positive net energy productions, control and pretreated digesters at 80 °C were more favorable at an SRT of 10 d. PMID:23866153

Mehdizadeh, Seyedeh Neda; Eskicioglu, Cigdem; Bobowski, Jake; Johnson, Thomas

2013-06-07

435

Effect of anaerobic fungi on in vitro feed digestion by mixed rumen microflora of buffalo.  

PubMed

Five strains of anaerobic fungi isolated from the faeces of wild (hog deer, Cervus porcinus; blackbuck, Antelope cervicapra; spotted deer, Axis axis; nilgai, Baselophus tragocamelus) and rumen liquor of domestic (sheep, Ovies aries) ruminants showing high fibrolytic enzyme producing ability were added to mixed rumen microflora of buffalo to study their effect on the digestibility of lignocellulosic feed (wheat straw and wheat bran in the ratio of 80:20), enzyme production and fermentation end products in in vitro conditions. Among the 5 isolates studied, FNG5 (isolated from nilgai) showed the highest stimulating effect on apparent digestibility (35.31 +/- 1.61% vs. 28.61 +/- 1.55%; P < 0.05), true digestibility (43.64 +/- 1.73% vs. 35.37 +/- 1.65%; P < 0.01), neutral detergent fiber digestibility (29.30 +/- 2.58% vs. 18.47 +/- 2.12; P < 0.01) of feed 24 h after inoculation compared to the control group. The production of carboxymethyl cellulase, xylanase, acetyl esterase and beta-glucosidase was significantly (P < 0.05) higher in the FNG5 inoculated incubation medium. There was no improvement in the digestibility and enzyme production on the addition of the other 4 isolates. Total volatile fatty acid levels as well as the concentration of acetate, propionate, isobutyrate and valerate were significantly higher in the FNG5 added group as compared to the control group. The fungal isolate FNG5 from nilgai, a wild ruminant, was found to be superior to the other isolates tested and appears to have a potential to be used as a feed additive for improving fiber degradation in domestic ruminants. PMID:15535463

Paul, Shyam Sunder; Kamra, Devki Nandan; Sastry, Vadali Rama Bhadra; Sahu, Narottam Prasad; Agarwal, Neeta

436

Anaerobic digestion of pressed off leachate from the organic fraction of municipal solid waste  

SciTech Connect

A highly polluted liquid ('press water') was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of 'press water' as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 {sup o}C. A high methane productivity of 270 m{sup -3} CH{sub 4} ton{sup -1} COD{sub added} or 490 m{sup -3} CH{sub 4} ton{sup -1} VS{sub added} was achieved in the batch experiment. The semi-continuously run laboratory-scale reactor was initially operated at an organic loading rate of 10.7 kg COD m{sup -3} d{sup -1}. The loading was increased to finally 27.7 kg COD m{sup -3} d{sup -1}, corresponding to a reduction of the hydraulic retention time from initially 20 to finally 7.7 days. During the digestion, a stable elimination of organic material (measured as COD elimination) of approximately 60% was achieved. Linearly with the increment of the OLR, the volumetric methane production of the reactor increased from 2.6 m{sup 3} m{sub reactor}{sup -3} d{sup -1} to 7.1 m{sup 3} m{sub reactor}{sup -3} d{sup -1}. The results indicated that 'press water' from the organic fraction of municipal solid waste was a suitable substrate for anaerobic digestion which gave a high biogas yield even at very high loading rates.

Nayono, Satoto E. [Department of Civil Engineering, Yogyakarta State University, Campus UNY Karangmalang Yogyakarta 55281 (Indonesia); Institute of Biology for Engineers and Biotechnology of Wastewater, University of Karlsruhe, Am Fasanengarten, 76131 Karlsruhe (Germany); Winter, Josef, E-mail: josef.winter@iba.uka.d [Institute of Biology for Engineers and Biotechnology of Wastewater, University of Karlsruhe, Am Fasanengarten, 76131 Karlsruhe (Germany); Gallert, Claudia [Institute of Biology for Engineers and Biotechnology of Wastewater, University of Karlsruhe, Am Fasanengarten, 76131 Karlsruhe (Germany)