Combination of upflow anaerobic sludge blanket (UASB) reactor and partial nitritation/anammox moving bed biofilm reactor (MBBR) for municipal wastewater treatment.

PubMed

Malovanyy, Andriy; Yang, Jingjing; Trela, Jozef; Plaza, Elzbieta

2015-03-01

In this study the combination of an upflow anaerobic sludge blanket (UASB) reactor and a deammonification moving bed biofilm reactor (MBBR) for mainstream wastewater treatment was tested. The competition between aerobic ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) was studied during a 5months period of transition from reject water to mainstream wastewater followed by a 16months period of mainstream wastewater treatment. The decrease of influent ammonium concentration led to a wash-out of suspended biomass which had a major contribution to nitrite production. Influence of a dissolved oxygen concentration and a transient anoxia mechanism of NOB suppression were studied. It was shown that anoxic phase duration has no effect on NOB metabolism recovery and oxygen diffusion rather than affinities of AOB and NOB to oxygen determine the rate of nitrogen conversion in a biofilm system. Anammox activity remained on the level comparable to reject water treatment systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of Copper Contaminated Municipal Wastewater by Using UASB Reactor and Sand-Chemically Carbonized Rubber Wood Sawdust Column

PubMed Central

Biswas, Swarup; Mishra, Umesh

2016-01-01

The performance of a laboratory scale upflow anaerobic sludge blanket (UASB) reactor and its posttreatment unit of sand-chemically carbonized rubber wood sawdust (CCRWSD) column system for the treatment of a metal contaminated municipal wastewater was investigated. Copper ion contaminated municipal wastewater was introduced to a laboratory scale UASB reactor and the effluent from UASB reactor was then followed by treatment with sand-CCRWSD column system. The laboratory scale UASB reactor and column system were observed for a period of 121 days. After the posttreatment column the average removal of monitoring parameters such as copper ion concentration (91.37%), biochemical oxygen demand (BODT) (93.98%), chemical oxygen demand (COD) (95.59%), total suspended solid (TSS) (95.98%), ammonia (80.68%), nitrite (79.71%), nitrate (71.16%), phosphorous (44.77%), total coliform (TC) (99.9%), and fecal coliform (FC) (99.9%) was measured. The characterization of the chemically carbonized rubber wood sawdust was done by scanning electron microscope (SEM), X-ray fluorescence spectrum (XRF), and Fourier transforms infrared spectroscopy (FTIR). Overall the system was found to be an efficient and economical process for the treatment of copper contaminated municipal wastewater. PMID:26904681

Treatment of Copper Contaminated Municipal Wastewater by Using UASB Reactor and Sand-Chemically Carbonized Rubber Wood Sawdust Column.

PubMed

Biswas, Swarup; Mishra, Umesh

2016-01-01

The performance of a laboratory scale upflow anaerobic sludge blanket (UASB) reactor and its posttreatment unit of sand-chemically carbonized rubber wood sawdust (CCRWSD) column system for the treatment of a metal contaminated municipal wastewater was investigated. Copper ion contaminated municipal wastewater was introduced to a laboratory scale UASB reactor and the effluent from UASB reactor was then followed by treatment with sand-CCRWSD column system. The laboratory scale UASB reactor and column system were observed for a period of 121 days. After the posttreatment column the average removal of monitoring parameters such as copper ion concentration (91.37%), biochemical oxygen demand (BODT) (93.98%), chemical oxygen demand (COD) (95.59%), total suspended solid (TSS) (95.98%), ammonia (80.68%), nitrite (79.71%), nitrate (71.16%), phosphorous (44.77%), total coliform (TC) (99.9%), and fecal coliform (FC) (99.9%) was measured. The characterization of the chemically carbonized rubber wood sawdust was done by scanning electron microscope (SEM), X-ray fluorescence spectrum (XRF), and Fourier transforms infrared spectroscopy (FTIR). Overall the system was found to be an efficient and economical process for the treatment of copper contaminated municipal wastewater.

Organic loading rate effect on the acidogenesis of cheese whey: a comparison between UASB and SBR reactors.

PubMed

Calero, R; Iglesias-Iglesias, R; Kennes, C; Veiga, M C

2017-09-16

Volatile fatty acids (VFA) production and degree of acidification (DA) were investigated in the anaerobic treatment of cheese whey by comparison of two processes: a continuous process using a laboratory upflow anaerobic sludge blanket (UASB) reactor and a discontinuous process using a sequencing batch reactor (SBR). The main purpose of this work was to study the organic loading rate (OLR) effect on the yield of VFA in two kinds of reactors. The predominant products in the acidogenic process in both reactors were: acetate, propionate, butyrate and valerate. The maximum DA obtained was 98% in an SBR at OLR of 2.7 g COD L -1 d -1 , and 97% in the UASB at OLR at 15.1 g COD L -1 d -1 . The results revealed that the UASB reactor was more efficient at a medium OLR with a higher VFA yield, while with the SBR reactor, the maximum acidification was obtained at a lower OLR with changes in the VFA profile at different OLRs applied.

Improving hydrolysis of food waste in a leach bed reactor

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

Browne, James D.; Allen, Eoin; Murphy, Jerry D., E-mail: jerry.murphy@ucc.ie

2013-11-15

Highlights: • This paper assesses leaching of food waste in a two phase digestion system. • Leaching is assessed with and without an upflow anaerobic sludge blanket (UASB). • Without the UASB, low pH reduces hydrolysis, while increased flows increase leaching. • Inclusion of the UASB increases pH to optimal levels and greatly improves leaching. • The optimal conditions are suggested as low flow with connection to the UASB. - Abstract: This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a lowmore » and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB.« less

Comparative performance evaluation of full-scale anaerobic and aerobic wastewater treatment processes in Brazil.

PubMed

von Sperling, M; Oliveira, S C

2009-01-01

This article evaluates and compares the actual behavior of 166 full-scale anaerobic and aerobic wastewater treatment plants in operation in Brazil, providing information on the performance of the processes in terms of the quality of the generated effluent and the removal efficiency achieved. The observed results of effluent concentrations and removal efficiencies of the constituents BOD, COD, TSS (total suspended solids), TN (total nitrogen), TP (total phosphorus) and FC (faecal or thermotolerant coliforms) have been compared with the typical expected performance reported in the literature. The treatment technologies selected for study were: (a) predominantly anaerobic: (i) septic tank + anaerobic filter (ST + AF), (ii) UASB reactor without post-treatment (UASB) and (iii) UASB reactor followed by several post-treatment processes (UASB + POST); (b) predominantly aerobic: (iv) facultative pond (FP), (v) anaerobic pond followed by facultative pond (AP + FP) and (vi) activated sludge (AS). The results, confirmed by statistical tests, showed that, in general, the best performance was achieved by AS, but closely followed by UASB reactor, when operating with any kind of post-treatment. The effluent quality of the anaerobic processes ST + AF and UASB reactor without post-treatment was very similar to the one presented by facultative pond, a simpler aerobic process, regarding organic matter.

Enhanced biodegradation of hexachlorocyclohexane in upflow anaerobic sludge blanket reactor using methanol as an electron donor.

PubMed

Bhatt, Praveena; Kumar, M Suresh; Mudliar, Sandeep; Chakrabarti, Tapan

2008-05-01

Anaerobic dechlorination of technical grade hexachlorocyclohexane (THCH) was studied in a continuous upflow anaerobic sludge blanket (UASB) reactor with methanol as a supplementary substrate and electron donor. A reactor without methanol served as the experimental control. The inlet feed concentration of THCH in both the experimental and the control UASB reactor was 100 mg l(-1). After 60 days of continuous operation, the removal of THCH was >99% in the methanol-supplemented reactor as compared to 20-35% in the control reactor. THCH was completely dechlorinated in the methanol fed reactor at 48 h HRT after 2 months of continuous operation. This period was also accompanied by increase in biomass in the reactor, which was not observed in the experimental control. Batch studies using other supplementary substrates as well as electron donors namely acetate, butyrate, formate and ethanol showed lower % dechlorination (<85%) and dechlorination rates (<3 mg g(-1)d(-1)) as compared to methanol (98%, 5 mg g(-1)d(-1)). The optimum concentration of methanol required, for stable dechlorination of THCH (100 mg l(-1)) in the UASB reactor, was found to be 500 mg l(-1). Results indicate that addition of methanol as electron donor enhances dechlorination of THCH at high inlet concentration, and is also required for stable UASB reactor performance.

Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors.

PubMed

Aangelidaki, I; Ahrin, B K; Deng, H; Schmidt, J E

2002-01-01

Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process. Furthermore, it was found that methane productions rates during digestion of either swine manure alone or OME alone were much lower than the rates achieved when OME and manure were digested together. Admixing OME with manure at a concentration of 5 to 10% OME resulted in the highest methane production rates. Using upflow anaerobic sludge blanket (UASB) reactors, it was shown that codigestion of OME with swine manure (up to 50% OME) was successful with a COD reduction up to 75%. The process was adapted for degradation of OME with stepwise increase of the OME load to the UASB reactor. The results showed that the high content of ammonia in swine manure, together with content of other nutrients, make it possible to degrade OME without addition of external alkalinity and without addition of external nitrogen source. Anaerobic treatment of OME in UASB reactors resulted in reduction of simple phenolic compounds such as mequinol, phenyl ethyl alcohol and ethyl methyl phenol. After anaerobic treatment the concentration of these compounds was reduced between 75 and 100%. However, the concentration of some degradation products such as methyl phenol and ethyl phenol were detected in significantly higher concentrations after treatment, indicating that the process has to be further optimised to achieve satisfactory removal of all xenobiotic compounds.

Demonstration of a full-scale plant using an UASB followed by a ceramic MBR for the reclamation of industrial wastewater.

PubMed

Niwa, Terutake; Hatamoto, Masashi; Yamashita, Takuya; Noguchi, Hiroshi; Takase, Osamu; Kekre, Kiran A; Ang, Wui Seng; Tao, Guihe; Seah, Harry; Yamaguchi, Takashi

2016-10-01

This study comprehensively evaluated the performance of a full-scale plant (4550m(3)d(-1)) using a UASB reactor followed by a ceramic MBR for the reclamation and reuse of mixed industrial wastewater containing many inorganics, chemical, oil and greases. This plant was demonstrated as the first full-scale system to reclaim the mixed industrial wastewater in the world. During 395days of operation, influent chemical oxygen demand (COD) fluctuated widely, but this system achieved COD removal rate of 91% and the ceramic MBR have operated flux of 21-25LMH stably. This means that this system adsorbed the feed water fluctuation and properly treated the water. Energy consumption of this plant was achieved 0.76kWhmm(-3) and this value is same range of domestic sewage MBR system. The combination of an UASB reactor and ceramic MBR is the most economical and feasible solution for water reclamation of mixed industrial wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage.

PubMed

Aida, Azrina A; Hatamoto, Masashi; Yamamoto, Masamitsu; Ono, Shinya; Nakamura, Akinobu; Takahashi, Masanobu; Yamaguchi, Takashi

2014-11-01

A novel wastewater treatment system consisting of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with sulfur-redox reaction was developed for treatment of municipal sewage under low-temperature conditions. In the UASB reactor, a novel phenomenon of anaerobic sulfur oxidation occurred in the absence of oxygen, nitrite and nitrate as electron acceptors. The microorganisms involved in anaerobic sulfur oxidation have not been elucidated. Therefore, in this study, we studied the microbial communities existing in the UASB reactor that probably enhanced anaerobic sulfur oxidation. Sludge samples collected from the UASB reactor before and after sulfur oxidation were used for cloning and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes of the bacterial and archaeal domains. The microbial community structures of bacteria and archaea indicated that the genus Smithella and uncultured bacteria within the phylum Caldiserica were the dominant bacteria groups. Methanosaeta spp. was the dominant group of the domain archaea. The T-RFLP analysis, which was consistent with the cloning results, also yielded characteristic fingerprints for bacterial communities, whereas the archaeal community structure yielded stable microbial community. From these results, it can be presumed that these major bacteria groups, genus Smithella and uncultured bacteria within the phylum Caldiserica, probably play an important role in sulfur oxidation in UASB reactors. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effect of pentachlorophenol and chemical oxygen demand mass concentrations in influent on operational behaviors of upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Shen, Dong-Sheng; He, Ruo; Liu, Xin-Wen; Long, Yan

2006-08-25

Upflow anaerobic sludge blanket (UASB) reactor that was seeded with anaerobic sludge acclimated to chlorophenols was used to investigate the feasibility of anaerobic biotreatment of synthetic wastewater containing pentachlorophenol (PCP) with additional sucrose as carbon source. Two sets of UASB reactors were operated at one time. But the seeded sludge for the two reactors was different and Reactor I was seeded with the sludge that was acclimated to PCP completely for half a year, and Reactor II was seeded with the mixed sludge that was acclimated for half a year to PCP, 4-CP, 3-CP or 2-CP, respectively. The degradation of PCP and the operation fee treating the wastewater are affected by the concentration of MEDS (microorganism easily degradable substrate). So the confirmation of the suitable ratio of [COD] and [PCP] was the key factor of treating the wastewater containing PCP economically and efficiently. During the experiment, the synthetic wastewater with 180.0 mg L(-1) PCP and 1250-10000 mg L(-1) COD could be treated steadily in the experimental Reactor I. The removal efficiency of PCP was more than 99.5% and the removal efficiency of COD was up to 90%. [PCP] (concentration of PCP) in effluent was less than 0.5 mg L(-1). [PCP] in influent could affect proper [COD] (concentration of COD) range in influent that was required for maintenance of steady running of the experimental reactor with a hydraulic retention time (HRT) from 20 to 22 h. [PCP] in influent would directly affect the necessary [COD] in influent when the UASB reactor ran normally and treated the wastewater containing PCP. When [PCP] was 100.4, 151.6 and 180.8 mg L(-1) in influent, respectively, [COD] in influent had to be controlled about 1250-7500, 2500-5000 and 5000 mg L(-1) to maintain the UASB reactor steady running normally and contemporarily ensure that [COD] and [PCP] in effluent were less than 300 and 0.5 mg L(-1), respectively. With the increase of [PCP] in influent, the range of variation of [COD] in influent endured by the UASB reactor was decreasing. The ratios of [COD] and [PCP] in influent could affect removal efficiency of PCP and COD, the concentration of total volatile fatty acids (VFA) in effluent, biogas quantity and methane content in biogas. [PCP] in influent was linearly or semi-logarithmically correlated to [COD] in effluent when [COD] in influent was 5750+/-250 mg L(-1), and so was the relationship between [COD] in influent and [PCP] in effluent when [PCP] in influent was 100.4 or 151.6 mg L(-1), less than the maximum permissible [PCP]. The sources of seeded sludge, the way of sludge acclimation and the characteristics of anaerobic sludge could all affect the UASB reactor capacity treating PCP. When [PCP] were less than 180.8 mg L(-1) for Reactor I and 151.6 mg L(-1) for Reactor II, the variation of [PCP] in influent had little effect on the UASB reactor volume gas production rate and substrate gas production rate. And [VFA] and pH value in effluent were affected a little. Volume biogas production rate and substrate biogas production rate of the UASB reactor were only affected by [COD] and loading rate in influent. But when [PCP] was more than 151.6 mg L(-1) for Reactor II, the biogas production fell quickly and was over 3 days later. [VFA] in effluent from Reactor II increased up to 2198.1 mg L(-1) quickly and the pH value fell to less than 7. Reactor II could not run normally. The component of VFA accumulated quickly was mainly acetate (above 50%). With [PCP] increased from 7.9 to 180.8 mg L(-1) gradually in influent, the methane content in biogas from Reactor II decreased from 70% to 60%, but the reactor could still run normally. Then as for Reactor II, the content of methane have fallen from 75% to 45% or so quickly. And Reactor II could not run steadily. So the conclusion could be drown that too high [PCP] in influent for UASB reactor mainly inhibited the activity of methane-producing bacteria cultures utilizing the acetate.

Recovery of elemental sulphur from anaerobic effluents through the biological oxidation of sulphides.

PubMed

de Sousa, José Tavares; Lima, Jéssyca de Freitas; da Silva, Valquíria Cordeiro; Leite, Valderi Duarte; Lopes, Wilton Silva

2017-03-01

The aim of the present study was to evaluate the biological oxidation of sulphide in two different UASB reactors by assessing the occurrence of oxidized forms of sulphur in the effluents and the amount of S 0 that could be recovered in the process. The bioreactors employed were an anaerobic hybrid (AH) reactor employing porous polyurethane foam as support media and a micro-aerated UASB reactor equipped with an aeration device above the digestion zone. The AH reactor produced a final effluent containing low concentrations of S 2- (3.87% of total sulphur load). It was achieved due to a complete oxidation of 56.1% of total sulphur. The partial biological oxidation that occurred in the AH reactor allowed the recovery of 30% of the sulphur load as S 0 . The effluent from the micro-aerated UASB reactor contained 5% of the sulphur load in the form of S 2- , while 20.9% was present as dissolved SO 4 2- and 46% was precipitated as S 0 . It is concluded that the AH reactor or micro-aeration carried out above the digestion zone of the UASB reactor favoured the biological oxidation of S 2- and the release of odourless effluents. Both technologies represent feasible and low-cost alternatives for the anaerobic treatment of domestic sewage.

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.

PubMed

Gangagni Rao, A; Sasi Kanth Reddy, T; Surya Prakash, S; Vanajakshi, J; Joseph, Johny; Jetty, Annapurna; Rajashekhara Reddy, A; Sarma, P N

2008-12-01

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper.

Biodegradation of tech-hexachlorocyclohexane in a upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Bhat, Praveena; Kumar, M Suresh; Mudliar, Sandeep N; Chakrabarti, T

2006-04-01

Biodegradability of technical grade hexachlorocyclohexane (tech-HCH) was studied in an upflow anaerobic sludge blanket reactor (UASB) under continuous mode of operation in concentration range of 100-200 mg/l and constant HRT of 48 h. At steady state operation more than 85% removal of tech-HCH (upto 175 mg/l concentration) and complete disappearance of beta-HCH was observed. Kinetic constants in terms of maximum specific tech-HCH utilization rate (k) and half saturation velocity constant (K(L)) were found to be 11.88 mg/g/day and 8.11 mg/g/day, respectively. The tech-HCH degrading seed preparation, UASB reactor startup and degradation in continuous mode of operation of the reactor is presented in this paper.

Sewage treatment in integrated system of UASB reactor and duckweed pond and reuse for aquaculture.

PubMed

Mohapatra, D P; Ghangrekar, M M; Mitra, A; Brar, S K

2012-06-01

The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and a duckweed pond containing Lemna gibba was investigated for suitability for treating effluent for use in aquaculture. While treating low-strength sewage having a chemical oxygen demand (COD) of typically less than 200 mg/L, with an increase in hydraulic retention time (HRT) from 10.04 to 33.49 h, COD removal efficiency of the UASB reactor decreased owing to a decrease in organic loading rate (OLR) causing poor mixing in the reactor. However, even at the lower OLR (0.475 kg COD/(m3 x d)), the UASB reactor gave a removal efficiency of 68% for COD and 74% for biochemical oxygen demand (BOD). The maximum COD, BOD, ammonia-nitrogen and phosphate removal efficiencies of the duckweed pond were 40.77%, 38.01%, 61.87% and 88.57%, respectively. Decreasing the OLR by increasing the HRT resulted in an increase in efficiency of the duckweed pond for removal of ammonia-nitrogen and phosphate. The OLR of 0.005 kg COD/(m2 x d) and HRT of 108 h in the duckweed pond satisfied aquaculture quality requirements. A specific growth rate of 0.23% was observed for tilapia fish fed with duckweed harvested from the duckweed pond. The economic analysis proved that it was beneficial to use the integrated system of a UASB reactor and a duckweed pond for treatment of sewage.

A case study of coupling upflow anaerobic sludge blanket (UASB) and ANITA™ Mox process to treat high-strength landfill leachate.

PubMed

Lu, Ting; George, Biju; Zhao, Hong; Liu, Wenjun

2016-01-01

A pilot study was conducted to study the treatability of high-strength landfill leachate by a combined process including upflow anaerobic sludge blanket (UASB), carbon removal (C-stage) moving bed biofilm reactor (MBBR) and ANITA™ Mox process. The major innovation on this pilot study is the patent-pending process invented by Veolia that integrates the above three unit processes with an effluent recycle stream, which not only maintains the low hydraulic retention time to enhance the treatment performance but also reduces inhibiting effect from chemicals present in the high-strength leachate. This pilot study has demonstrated that the combined process was capable of treating high-strength leachate with efficient chemical oxygen demand (COD) and nitrogen removals. The COD removal efficiency by the UASB was 93% (from 45,000 to 3,000 mg/L) at a loading rate of 10 kg/(m(3)·d). The C-stage MBBR removed an additional 500 to 1,000 mg/L of COD at a surface removal rate (SRR) of 5 g/(m(2)·d) and precipitated 400 mg/L of calcium. The total inorganic nitrogen removal efficiency by the ANITA Mox reactor was about 70% at SRR of 1.0 g/(m(2)·d).

Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage

PubMed Central

Aida, Azrina A.; Kuroda, Kyohei; Yamamoto, Masamitsu; Nakamura, Akinobu; Hatamoto, Masashi; Yamaguchi, Takashi

2015-01-01

We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors. PMID:25817585

Recovery and biological oxidation of dissolved methane in effluent from UASB treatment of municipal sewage using a two-stage closed downflow hanging sponge system.

PubMed

Matsuura, Norihisa; Hatamoto, Masashi; Sumino, Haruhiko; Syutsubo, Kazuaki; Yamaguchi, Takashi; Ohashi, Akiyoshi

2015-03-15

A two-stage closed downflow hanging sponge (DHS) reactor was used as a post-treatment to prevent methane being emitted from upflow anaerobic sludge blanket (UASB) effluents containing unrecovered dissolved methane. The performance of the closed DHS reactor was evaluated using real municipal sewage at ambient temperatures (10-28 °C) for one year. The first stage of the closed DHS reactor was intended to recover dissolved methane from the UASB effluent and produce a burnable gas with a methane concentration greater than 30%, and its recovery efficiency was 57-88%, although the amount of dissolved methane in the UASB effluent fluctuated in the range of 46-68 % of methane production greatly depending on the temperature. The residual methane was oxidized and the remaining organic carbon was removed in the second closed DHS reactor, and this reactor performed very well, removing more than 99% of the dissolved methane during the experimental period. The rate at which air was supplied to the DHS reactor was found to be one of the most important operating parameters. Microbial community analysis revealed that seasonal changes in the methane-oxidizing bacteria were key to preventing methane emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhancement of a UASB-septic tank performance for decentralised treatment of strong domestic sewage.

PubMed

Mahmoud, Nidal; van Lier, Jules B

2011-01-01

The possibility of enhancing the process performance of the UASB-septic tank for treating strong sewage in Palestine by means of inoculating the reactor with well adapted anaerobic sludge and/or adding a packing media to the upper part of the reactor, creating an anaerobic hybrid (AH)-septic tank, was investigated. To achieve these objectives, two community onsite UASB-septic tank and AH-septic tank were operated in parallel at 2 days HRT for around 8 months overlapping the cold and hot periods of the year in Palestine. The achieved removal efficiencies of CODtot in the UASB-septic tank and AH-septic tank during the first months of operation, coinciding with the cold period and the subsequent hot period, were respectively 50 (+/- 15)% and 48 (+/- 15)% and 66 (+/- 8)% and 55 (+/- 8)%. This shows that the UASB-septic tank performed significantly better (p < 0.05) than the AH-septic tank after rather long periods of operation. The difference in the CODtot removal efficiency was mainly due to the better CODss removal efficiencies in the UASB-septic tank. The removal efficiencies over the last 50 days of operation for CODtot, CODsus, CODcol and CODdis were 70, 72, 77 and 55% and 53, 54, 78 and 45% for the UASB-septic tank and AH-septic tank, respectively. Comparing the here achieved COD removal efficiencies with previously reported efficiencies of UASB-septic tanks operated in Palestine shows that the reactor performance in terms of COD removal and conversion, during the first 8 months of operation, has improved substantially by being started with well adapted anaerobic sludge, simulating and predicting long-term performance. Adding packing media did not lead to an improvement.

Oily wastewater treatment using a novel hybrid PBR-UASB system.

PubMed

Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2007-04-01

In this study, anaerobic treatability of oily wastewater was investigated in a hybrid reactor system consisting of a packed bed reactor (PBR) followed by an upflow anaerobic sludge blanket (UASB) reactor at 35 degrees C. The system was operated using real pet food wastewater at different hydraulic retention times and loading rates for 165 d. The PBR was packed with sol-gel/alginate beads containing immobilized enzyme which hydrolyzed the oil and grease (O&G) into free long chain fatty acids, that were biodegraded by the UASB. The hybrid system was operated up to an oil loading rate of 4.9 kg O&Gm(-3)d(-1) (to the PBR) without any operational problems for a period of 100 d, with COD and O&G removal efficiencies above 90% and no sludge flotation was observed in the UASB. Beads supplement to the PBR was less than 2 g d(-1) and the relative activity was about 70%. Further increment in O&G loading to 18.7 kg O&Gm(-3)d(-1) caused destabilization of the system with 0.35% (v float/v feed) sludge float removed from the UASB.

A dual purpose packed-bed reactor for biogas scrubbing and methane-dependent water quality improvement applying to a wastewater treatment system consisting of UASB reactor and trickling filter.

PubMed

Tanaka, Yasuo

2002-08-01

A wastewater treatment system employing a UASB reactor in temperate regions requires biogas as a heat source for the UASB reactor during low temperature seasons. In this case, removal of H2S in the biogas by means of a scrubber before burning is necessary in order to prevent the boilers from corroding. Heating of the UASB reactor is, however, unnecessary in a warm season, and the scrubber and biogas become useless. Methane-dependent water quality improvement using the scrubber and biogas would be one way to use them efficiently during the warm season. The possible dual-purpose use of a packed-bed reactor was examined, with one of its uses being the scrubbing of biogas during the cold season and the other being the methane-dependent improvement of effluent water quality during the warm season. A bench scale packed-bed filled with plastic latticed-ring media was installed in a livestock wastewater treatment plant consisting of a UASB reactor and a trickling filter for post-treatment. The packed-bed was operated with biogas flowing at a superficial velocity of 0.14-0.39 m h(-1) and the hydraulic loading of trickling filter effluent sprayed onto the media 9.4-26.1 m3 m2 day(-1). H2S in the biogas from the UASB reactor was reduced from 1,200-2,500 ppm to less than 2 ppm by the reactor. Methane-dependent water quality improvement was examined using a laboratory scale reactor to which methane and/or air was supplied from the bottom, while plant effluent was spread from the top of the reactor. When the mixture gas of methane and air (volume ratio 1:3) was added to the reactor, biofilm grew on the surface of the media. Accompanying this growth, ammonium and phosphate in the spread water decreased, probably due to assimilation by the methane-oxidizing bacteria. Though assimilation activity dropped after the accumulation of biomass, it could be reactivated by washing out the excess biomass. Periodical backwash at a rate of more than once a week seemed to efficiently maintain the removal activity. The dark brown color of the wastewater could be also reduced in concert with methane oxidation. It seemed that methane-oxidizing bacteria degraded color-causing compounds. These results suggest that the packed-bed reactor is useful for both H2S purification of biogas and methane-dependent effluent water quality improvement.

Fate of personal care and household products in source separated sanitation.

PubMed

Butkovskyi, A; Rijnaarts, H H M; Zeeman, G; Hernandez Leal, L

2016-12-15

Removal of twelve micropollutants, namely biocides, fragrances, ultraviolet (UV)-filters and preservatives in source separated grey and black water treatment systems was studied. All compounds were present in influent grey water in μg/l range. Seven compounds were found in influent black water. Their removal in an aerobic activated sludge system treating grey water ranged from 59% for avobenzone to >99% for hexylcinnamaldehyde. High concentrations of hydrophobic micropollutants in sludge of aerobic activated sludge system indicated the importance of sorption for their removal. Six micropollutants were found in sludge of an Up-flow anaerobic sludge blanket (UASB) reactor treating black water, with four of them being present at significantly higher concentrations after addition of grey water sludge to the reactor. Hence, addition of grey water sludge to the UASB reactor is likely to increase micropollutant content in UASB sludge. This approach should not be followed when excess UASB sludge is designed to be reused as soil amendment. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparison of the technological effectiveness of dairy wastewater treatment in anaerobic UASB reactor and anaerobic reactor with an innovative design.

PubMed

Jedrzejewska-Cicinska, M; Kozak, K; Krzemieniewski, M

2007-10-01

The present research was an investigation of the influence of an innovative design of reactor filled with polyethylene (PE) granulate on model dairy wastewater treatment efficiency under anaerobic conditions compared to that obtained in a typical UASB reactor. The experiment was conducted at laboratory scale. An innovative reactor was designed with the reaction chamber inclined 30 degrees in relation to the ground with upward waste flow and was filled with PE granular material. Raw model dairy wastewater was fed to two anaerobic reactors of different design at the organic loading rate of 4 kg COD m(-3)d(-1). Throughout the experiment, a higher removal efficiency of organic compounds was observed in the reactor with an innovative design and it was higher by 7.1% on average than in the UASB reactor. The total suspended solids was lower in the wastewater treated in the anaerobic reactor with the innovative design. Applying a PE granulated filling in the chamber of the innovative reactor contributed to an even distribution of sludge biomass in the reactor, reducing washout of anaerobic sludge biomass from the reaction chamber and giving a higher organic compounds removal efficiency.

The close relation between Lactococcus and Methanosaeta is a keystone for stable methane production from molasses wastewater in a UASB reactor.

PubMed

Kim, Tae Gwan; Yun, Jeonghee; Cho, Kyung-Suk

2015-10-01

The up-flow anaerobic sludge blanket (UASB) reactor is a promising method for the treatment of high-strength industrial wastewaters due to advantage of its high treatment capacity and settleable suspended biomass retention. Molasses wastewater as a sugar-rich waste is one of the most valuable raw material for bioenergy production due to its high organic strength and bioavailability. Interpretation for complex interactions of microbial community structures and operational parameters can help to establish stable biogas production. RNA-based approach for biogas production systems is recommended for analysis of functionally active community members which are significantly underestimated. In this study, methane production and active microbial community were characterized in an UASB reactor using molasses wastewater as feedstock. The UASB reactor achieved a stable process performance at an organic loading rate of 1.7~13.8-g chemical oxygen demand (COD,·L(-1) day(-1); 87-95 % COD removal efficiencies), and the maximum methane production rate was 4.01 L-CH4·at 13.8 g-COD L(-1) day(-1). Lactococcus and Methanosaeta were comprised up to 84 and 80 % of the active bacterial and archaeal communities, respectively. Network analysis of reactor performance and microbial community revealed that Lactococcus and Methanosaeta were network hub nodes and positively correlated each other. In addition, they were positively correlated with methane production and organic loading rate, and they shared the other microbial hub nodes as neighbors. The results indicate that the close association between Lactococcus and Methanosaeta is responsible for the stable production of methane in the UASB reactor using molasses wastewater.

Steady performance of a zero valent iron packed anaerobic reactor for azo dye wastewater treatment under variable influent quality.

PubMed

Zhang, Yaobin; Liu, Yiwen; Jing, Yanwen; Zhao, Zhiqiang; Quan, Xie

2012-01-01

Zero valent iron (ZVI) is expected to help create an enhanced anaerobic environment that might improve the performance of anaerobic treatment. Based on this idea, a novel ZVI packed upflow anaerobic sludge blanket (ZVI-UASB) reactor was developed to treat azo dye wastewater with variable influent quality. The results showed that the reactor was less influenced by increases of Reactive Brilliant Red X-3B concentration from 50 to 1000 mg/L and chemical oxygen demand (COD) from 1000 to 7000 mg/L in the feed than a reference UASB reactor without the ZVI. The ZVI decreased oxidation-reduction potential in the reactor by about 80 mV. Iron ion dissolution from the ZVI could buffer acidity in the reactor, the amount of which was related to the COD concentration. Fluorescence in situ hybridization test showed the abundance of methanogens in the sludge of the ZVI-UASB reactor was significantly greater than that of the reference one. Denaturing gradient gel electrophoresis showed that the ZVI increased the diversity of microbial strains responsible for high efficiency.

Corn industrial wastewater (nejayote): a promising substrate in Mexico for methane production in a coupled system (APCR-UASB).

PubMed

España-Gamboa, Elda; Domínguez-Maldonado, Jorge Arturo; Tapia-Tussell, Raul; Chale-Canul, Jose Silvano; Alzate-Gaviria, Liliana

2018-01-01

In Mexico, the corn tortilla is a food of great economic importance. Corn tortilla production generates about 1500-2000 m 3 of wastewater per 600 tons of processed corn. Although this wastewater (also known as nejayote) has a high organic matter content, few studies in Mexico have analyzed its treatment. This study presents fresh data on the potential methane production capacity of nejayote in a two-phase anaerobic digestion system using an Anaerobic-Packed Column Reactor (APCR) to optimize the acidogenic phase and an up-flow anaerobic sludge blanket (UASB) reactor to enhance the methanogenic process. Results indicate that day 8 was ideal to couple the APCR to the UASB reactor. This allowed for a 19-day treatment that yielded 96% COD removal and generated a biogas containing 84% methane. The methane yield was 282 L kg -1 of COD removed . Thus, two-phase anaerobic digestion is an efficient process to treat nejayote; furthermore, this study demonstrated the possibility of using an industrial application by coupling the APCR to the UASB reactor system, in order to assess its feasibility for biomethane generation as a sustainable bioenergy source.

Modified kinetic-hydraulic UASB reactor model for treatment of wastewater containing biodegradable organic substrates.

PubMed

El-Seddik, Mostafa M; Galal, Mona M; Radwan, A G; Abdel-Halim, Hisham S

2016-01-01

This paper addresses a modified kinetic-hydraulic model for up-flow anaerobic sludge blanket (UASB) reactor aimed to treat wastewater of biodegradable organic substrates as acetic acid based on Van der Meer model incorporated with biological granules inclusion. This dynamic model illustrates the biomass kinetic reaction rate for both direct and indirect growth of microorganisms coupled with the amount of biogas produced by methanogenic bacteria in bed and blanket zones of reactor. Moreover, the pH value required for substrate degradation at the peak specific growth rate of bacteria is discussed for Andrews' kinetics. The sensitivity analyses of biomass concentration with respect to fraction of volume of reactor occupied by granules and up-flow velocity are also demonstrated. Furthermore, the modified mass balance equations of reactor are applied during steady state using Newton Raphson technique to obtain a suitable degree of freedom for the modified model matching with the measured results of UASB Sanhour wastewater treatment plant in Fayoum, Egypt.

Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors.

PubMed

Rico, Carlos; Montes, Jesús A; Rico, José Luis

2017-08-01

Three different types of anaerobic sludge (granular, thickened digestate and anaerobic sewage) were evaluated as seed inoculum sources for the high rate anaerobic digestion of pig slurry in UASB reactors. Granular sludge performance was optimal, allowing a high efficiency process yielding a volumetric methane production rate of 4.1LCH 4 L -1 d -1 at 1.5days HRT (0.248LCH 4 g -1 COD) at an organic loading rate of 16.4gCODL -1 d -1 . The thickened digestate sludge experimented flotation problems, thus resulting inappropriate for the UASB process. The anaerobic sewage sludge reactor experimented biomass wash-out, but allowed high process efficiency operation at 3days HRT, yielding a volumetric methane production rate of 1.7LCH 4 L -1 d -1 (0.236LCH 4 g -1 COD) at an organic loading rate of 7.2gCODL -1 d -1 . To guarantee the success of the UASB process, the settleable solids of the slurry must be previously removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Organics, sulfates and ammonia removal from acrylic fiber manufacturing wastewater using a combined Fenton-UASB (2 phase)-SBR system.

PubMed

Li, Jin; Luan, Zhaokun; Yu, Lian; Ji, Zhongguang

2011-11-01

A combined Fenton-UASB (2 phase)-SBR system was employed to treat acrylic fiber manufacturing wastewater. The Chemical Oxygen Demand (COD) removal and effluent Biochemical Oxygen Demand (BOD) to COD were 65.5% and 0.529%, respectively, with the optimal Fenton conditions: ferrous was 300 mg/L; hydrogen peroxide was 500 mg/L; pH was 3.0; reaction time was 2.0 h. In two-phase UASB reactor, mesophilic operation (35±0.5 °C) was performed with hydraulic retention time (HRT) varied between 28 and 40 h. The results showed that with the HRT not less than 38 h, COD and sulfate removal were 65% and 75%, respectively. The greatest sizes of granule formed in the sulfate-reducing and methane-producing phases were 5 and 2 mm, respectively. Sulfate-reducing bacteria (SRB) accounted for 35% in the sulfate-reducing phase while methane-producing archaea (MPA) accounted for 72% in the methane-producing phase. During the SBR process, shortcut nitrification was achieved by temperature control of 30 °C. Copyright © 2011 Elsevier Ltd. All rights reserved.

Organic loading rate and food-to-microorganism ratio shape prokaryotic diversity in a demo-scale up-flow anaerobic sludge blanket reactor treating domestic wastewater.

PubMed

Cardinali-Rezende, Juliana; Araújo, Juliana C; Almeida, Paulo G S; Chernicharo, Carlos A L; Sanz, José L; Chartone-Souza, Edmar; Nascimento, Andréa M A

2013-12-01

We investigated the microbial community in an up-flow anaerobic sludge blanket (UASB) reactor treating domestic wastewater (DW) during two different periods of organic loading rate (OLR) and food-to-microorganism (F/M) ratio. 16S rDNA clone libraries were generated, and quantitative real-time PCR (qPCR) analyses were performed. Fluctuations in the OLR and F/M ratio affected the abundance and the composition of the UASB prokaryotic community, mainly at the species level, as well as the performance of the UASB reactor. The qPCR analysis suggested that there was a decrease in the bacterial cell number during the rainy season, when the OLR and F/M ratio were lower. However, the bacterial diversity was higher during this time, suggesting that the community degraded more diversified substrates. The diversity and the abundance of the archaeal community were higher when the F/M ratio was lower. Shifts in the methanogenic community composition might have influenced the route of methane production, with methane produced by acetotrophic methanogens (dry season), and by hydrogenotrophic, methylotrophic and acetotrophic methanogens (rainy season). This study revealed higher levels of bacterial diversity, metabolic specialization and chemical oxygen demand removal efficiency of the DW UASB reactor during the rainy season.

Characteristics of sludge developed under different loading conditions during UASB reactor start-up and granulation.

PubMed

Ghangrekar, M M; Asolekar, S R; Joshi, S G

2005-03-01

Sludge characteristics available inside the reactor are of vital importance to maximize advantages of UASB reactor. The organic loading rate and sludge loading rate applied during start-up are among the important parameters to govern the sludge characteristics. Effects of these loading rates on the characteristics of the sludge developed are evaluated in six laboratory scale UASB reactors. The sludge characteristics considered are VSS/SS ratio of the sludge, sludge volume index, specific gravity, settling velocity and metal contents of the sludge developed under different loading rates. The experimental results indicate that, for developing good characteristics sludge, during primary start-up from flocculent inoculum sludge, organic loading rate and sludge loading rate should be in the range of 2.0-4.5 kg COD/m3 d and 0.1-0.25 kg COD/kg VSS d, respectively (chemical oxygen demand, COD). Proper sludge granulation and higher COD removal efficiency will be achieved by these loading rates.

Anaerobic treatment for C and S removal in "zero-discharge" paper mills: effects of process design on S removal efficiencies.

PubMed

van Lier, J B; Lens, P N; Pol, L W

2001-01-01

Stringent environmental laws in Europe and Northern America lead to the development towards closure of the process water streams in pulp and paper mills. Application of a "zero-discharge" process is already a feasible option for the board and packaging paper industry, provided in-line treatment is applied. Concomitant energy conservation inside the mill results in process water temperatures of 50-60 degrees C. Thermophilic anaerobic treatment complemented with appropriate post-treatment is considered as the most cost-effective solution to meet re-use criteria of the process water and to keep its temperature. In the proposed closed-cycle, the anaerobic treatment step removes the largest fraction of the biodegradable COD and eliminates "S" as H2S from the process stream, without the use of additional chemicals. The anaerobic step is regarded as the only possible location to bleed "S" from the process water cycle. In laboratory experiments, the effect of upward liquid velocity (Vupw) and the specific gas loading rate (Vgas) on the S removal capacity of thermophilic anaerobic bio-reactors was investigated. Acidifying, sulphate reducing sludge bed reactors were fed with partly acidified synthetic paper mill wastewater and were operated at 55 degrees C and pH 6. The reactors were operated at organic loading rates up to 50 g COD.l-1.day-1 at COD/SO4(2-) ratios of 10. The effect of Vupw was researched by comparing the performance of a UASB reactor operated at 1.0 m.h-1 and an EGSB reactor, operated at 6.8 m.h-1. The Vupw had a strong effect on the fermentation patterns. In the UASB reactor, acidification yielded H2, acetate and propionate, leading to an accumulation of reducing equivalents. These were partly disposed of by the production of n-butyrate and n-valerate from propionate. In the EGSB reactor net acetate consumption was observed as well as high volumetric gas (CO2 and CH4) production rates. The higher gas production rates in the EGSB reactor resulted in higher S-stripping efficiencies. The effect of Vgas was further researched by comparing 2 UASB reactors which were sparged with N2 gas at a specific gas loading rate of 30 m3.m-2.day-1. In contrast to the regular UASB reactors, the gas-supplied UASB showed a more stable performance when the organic loading rates were increased. Also, the H2S stripping efficiency was 3-4 times higher in the gas-supplied UASB, reaching values of 67%. Higher values were not obtained owing to the relatively poor sulphate reduction efficiencies.

Continuous reduction of tellurite to recoverable tellurium nanoparticles using an upflow anaerobic sludge bed (UASB) reactor.

PubMed

Ramos-Ruiz, Adriana; Sesma-Martin, Juan; Sierra-Alvarez, Reyes; Field, Jim A

2017-01-01

According to the U.S. Department of Energy and the European Union, tellurium is a critical element needed for energy and defense technology. Thus methods are needed to recover tellurium from waste streams. The objectives of this study was to determine the feasibility of utilizing upflow anaerobic sludge bed (UASB) reactors to convert toxic tellurite (Te IV ) oxyanions to non-toxic insoluble elemental tellurium (Te 0 ) nanoparticles (NP) that are amendable to separation from aqueous effluents. The reactors were supplied with ethanol as the electron donating substrate to promote the biological reduction of Te IV . One reactor was additionally amended with the redox mediating flavonoid compound, riboflavin (RF), with the goal of enhancing the bioreduction of Te IV . Its performance was compared to a control reactor lacking RF. The continuous formation of Te 0 NPs using the UASB reactors was found to be feasible and remarkably improved by the addition of RF. The presence of this flavonoid was previously shown to enhance the conversion rate of Te IV by approximately 11-fold. In this study, we demonstrated that this was associated with the added benefit of reducing the toxic impact of Te IV towards the methanogenic consortium in the UASB and thus enabled a 4.7-fold higher conversion rate of the chemical oxygen demand. Taken as a whole, this work demonstrates the potential of a methanogenic granular sludge to be applied as a bioreactor technology producing recoverable Te 0 NPs in a continuous fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of low strength industrial cluster wastewater by anaerobic hybrid reactor.

PubMed

Kumar, Amit; Yadav, Asheesh Kumar; Sreekrishnan, T R; Satya, Santosh; Kaushik, C P

2008-05-01

The study was aimed at treating the complex, combined wastewater generated in Mangolpuri industrial cluster. It was considered as a low strength wastewater with respect to its organic content. Anaerobic treatment of this wastewater was studied using an anaerobic hybrid reactor (AHR) which combined the best features of both the upflow anaerobic sludge blanket (UASB) reactor and anaerobic fluidized bed rector (AFBR). The performance of the reactor under different organic and hydraulic loading rates were studied. The COD removal reached 94% at an organic loading rate (OLR) of 2.08 kg COD m(-3)d(-1) at an hydraulic retention time (HRT) of 6.0 h. The granules developed were characterized in terms of their diameter and terminal settling velocity.

Pretreatment of vinasse from the sugar refinery industry under non-sterile conditions by Trametes versicolor in a fluidized bed bioreactor and its effect when coupled to an UASB reactor.

PubMed

España-Gamboa, Elda; Vicent, Teresa; Font, Xavier; Dominguez-Maldonado, Jorge; Canto-Canché, Blondy; Alzate-Gaviria, Liliana

2017-01-01

During hydrous ethanol production from the sugar refinery industry in Mexico, vinasse is generated. Phenolic compounds and melanoidins contribute to its color and make degradation of the vinasse a difficult task. Although anaerobic digestion (AD) is feasible for vinasse treatment, the presence of recalcitrant compounds can be toxic or inhibitory for anaerobic microorganism. Therefore, this study presents new data on the coupled of the FBR (Fluidized Bed Bioreactor) to the UASB (Upflow Anaerobic Sludge Blanket) reactor under non-sterile conditions by T. versicolor . Nevertheless, for an industrial application, it is necessary to evaluate the performance in this kind of proposal system. Therefore, this study used a FBR for the removal of phenolic compounds (67%) and COD (38%) at non-sterile conditions. Continuous operation of the FBR was successfully for 26 days according to the literature. When the FBR was coupled to the UASB reactor, we obtained a better quality of effluent, furthermore methane content and yield were 74% and 0.18 m 3 CH 4 / kg COD removal respectively. This study demonstrated the possibility of using for an industrial application the coupled of the FBR to the UASB reactor under non-sterile conditions. Continuous operation of the FBR was carried out successfully for 26 days, which is the highest value found in the literature.

Biological alkylation and colloid formation of selenium in methanogenic UASB reactors.

PubMed

Lenz, Markus; Smit, Martijn; Binder, Patrick; van Aelst, Adriaan C; Lens, Piet N L

2008-01-01

Bioalkylation and colloid formation of selenium during selenate removal in upflow anaerobic sludge bed (UASB) bioreactors was investigated. The mesophilic (30 degrees C) UASB reactor (pH = 7.0) was operated for 175 d with lactate as electron donor at an organic loading rate of 2 g COD L(-1) d(-1) and a selenium loading rate of 3.16 mg Se L(-1) d(-1). Combining sequential filtration with ion chromatographic analysis for selenium oxyanions and solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) for alkylated selenium compounds allowed to entirely close the selenium mass balance in the liquid phase for most of the UASB operational runtime. Although selenate was removed to more than 98.6% from the liquid phase, a less efficient removal of dissolved selenium was observed due to the presence of dissolved alkylated selenium species (dimethylselenide and dimethyldiselenide) and colloidal selenium particles in the effluent. The alkylated and the colloidal fractions contributed up to 15 and 31%, respectively, to the dissolved selenium concentration. The size fractions of the colloidal dispersion were: 4 to 0.45 mum: up to 21%, 0.45 to 0.2 mum: up to 11%, and particles smaller than 0.2 mum: up to 8%. Particles of 4 to 0.45 mum were formed in the external settler, but did not settle. SEM-EDX analysis showed that microorganisms form these selenium containing colloidal particles extracellularly on their surface. Lowering the temperature by 10 degrees C for 6 h resulted in drastically reduced selenate removal efficiencies (after a delay of 1.5 d), accompanied by the temporary formation of an unknown, soluble, organic selenium species. This study shows that a careful process control is a prerequisite for selenium treatment in UASB bioreactors, as disturbances in the operational conditions induce elevated selenium effluent concentrations by alkylation and colloid formation.

Recovery strategies for tackling the impact of phenolic compounds in a UASB reactor treating coal gasification wastewater.

PubMed

Wang, Wei; Han, Hongjun

2012-01-01

The impact of phenolic compounds (around 3.2 g/L) resulted in a completely failed performance in a mesophilic UASB reactor treating coal gasification wastewater. The recovery strategies, including extension of HRT, dilution, oxygen-limited aeration, and addition of powdered activated carbon were evaluated in batch tests, in order to obtain the most appropriate way for the quick recovery of the failed reactor performance. Results indicated that addition of powdered activated carbon and oxygen-limited aeration were the best recovery strategies in the batch tests. In the UASB reactor, addition of powdered activated carbon of 1 g/L shortened the recovery time from 25 to 9 days and oxygen-limited aeration of 0-0.5 mgO2/L reduced the recovery time to 17 days. Reduction of bioavailable concentration of phenolic compounds and recovery of sludge activity were the decisive factors for the recovery strategies to tackle the impact of phenolic compounds in anaerobic treatment of coal gasification wastewater. Copyright © 2011 Elsevier Ltd. All rights reserved.

Occurrence of pharmaceuticals and endocrine disruptors in raw sewage and their behavior in UASB reactors operated at different hydraulic retention times.

PubMed

Queiroz, F B; Brandt, E M F; Aquino, S F; Chernicharo, C A L; Afonso, R J C F

2012-01-01

This work investigated the occurrence of pharmaceuticals and endocrine disrupting compounds (EDCs) in raw sewage (from Belo Horizonte city, Minas Gerais state, Brazil) and assessed their behavior in demo-scale upflow anaerobic sludge blanket reactors (UASB reactors) operated at different hydraulic retention times (HRT). The dissolved concentration of the studied micropollutants in the raw and treated sewage was obtained using solid phase extraction (SPE) followed by analysis in a liquid chromatography system coupled to a hybrid high resolution mass spectrometer consisting of an ion-trap and time of flight (LC-MS-IT-TOF). The natural (estradiol) and synthetic (ethinylestradiol) estrogens were hardly detected; when present, however, their concentrations were lower than the method quantification limits. The concentrations of bisphenol A and miconazole in raw sewage were similar to that reported in the literature (around 200 ng L⁻¹ and hardly detected, respectively). The antibiotics sulfamethoxazole (median 13.0 ng L⁻¹) and trimethoprim (median 61.5 ng L⁻¹), and the other pharmaceutical compounds (diclofenac and bezafibrate, with median 99.9 and 94.4 ng L⁻¹, respectively) were found in lower concentrations when compared with reports in the literature, which might indicate a lower consumption of such drugs in Brazil. The UASB reactors were inefficient in the removal of bisphenol A, and led to an increased concentration of nonylphenol in the effluent. The anaerobic reactors were also inefficient in the removal of diclofenac, and led to a partial removal of bezafibrate; whereas, for sulfamethoxazole there seemed to be a direct relationship between the HRT and removal efficiencies. For trimethoprim the sludge retention time (SRT) seemed to play an important role, although it was only partially removed in the UASB reactors.

Grey water characteristics and treatment options for rural areas in Jordan.

PubMed

Halalsheh, M; Dalahmeh, S; Sayed, M; Suleiman, W; Shareef, M; Mansour, M; Safi, M

2008-09-01

Low water consumption in rural areas in Jordan had resulted in the production of concentrated grey water. Average COD, BOD and TSS values were 2568mg/l, 1056mg/l and 845mg/l, respectively. The average grey water generation was measured to be 14L/c.d. Three different treatment options were selected based on certain criterions, and discussed in this article. The examined treatment systems are septic tank followed by intermittent sand filter; septic tank followed by wetlands; and UASB-hybrid reactor. Advantages and disadvantages of each system are presented. It was concluded that UASB-hybrid reactor would be the most suitable treatment option in terms of compactness and simplicity in operation. The volume of UASB-hybrid reactor was calculated to be 0.268m(3) with a surface area of 0.138m(2) for each house having 10 inhabitants on average. Produced effluent is expected to meet Jordanian standards set for reclaimed water reuse in irrigating fruit trees.

Effect of limited aeration on the anaerobic treatment of evaporator condensate from a sulfite pulp mill.

PubMed

Zhou, Weili; Imai, Tsuyoshi; Ukita, Masao; Li, Fusheng; Yuasa, Akira

2007-01-01

Serious inhibition was found in the regular up-flow anaerobic sludge blanket (UASB) reactor in treating the evaporator condensate from a sulfite pulp mill, which contained high strength sulfur compounds. After applying the direct limited aeration in the UASB, the inhibition was alleviated gradually and the activity of the microorganisms was recovered. The COD removal rate increased from 40% to 80% at the organic loading rate of 8kgCODm(-3)d(-1) and a hydraulic retention time of 12h. Limited aeration caused no oxygen inhibition to the anaerobic microorganisms but instigated sulfide oxidization and H(2)S removal, which was beneficial to the methanogens. The experiment confirmed the feasibility of applying limited aeration in the anaerobic reactor to alleviate the sulfide inhibition. It also proved that the anaerobic system was actually aerotolerant. SEM observation showed that the predominant microorganisms partly changed from rod-shaped methanogens to cocci after the UASB reactor was aerated.

A fast linear predictive adaptive model of packed bed coupled with UASB reactor treating onion waste to produce biofuel.

PubMed

Milquez-Sanabria, Harvey; Blanco-Cocom, Luis; Alzate-Gaviria, Liliana

2016-10-03

Agro-industrial wastes are an energy source for different industries. However, its application has not reached small industries. Previous and current research activities performed on the acidogenic phase of two-phase anaerobic digestion processes deal particularly with process optimization of the acid-phase reactors operating with a wide variety of substrates, both soluble and complex in nature. Mathematical models for anaerobic digestion have been developed to understand and improve the efficient operation of the process. At present, lineal models with the advantages of requiring less data, predicting future behavior and updating when a new set of data becomes available have been developed. The aim of this research was to contribute to the reduction of organic solid waste, generate biogas and develop a simple but accurate mathematical model to predict the behavior of the UASB reactor. The system was maintained separate for 14 days during which hydrolytic and acetogenic bacteria broke down onion waste, produced and accumulated volatile fatty acids. On this day, two reactors were coupled and the system continued for 16 days more. The biogas and methane yields and volatile solid reduction were 0.6 ± 0.05 m 3 (kg VS removed ) -1 , 0.43 ± 0.06 m 3 (kg VS removed ) -1 and 83.5 ± 9.8 %, respectively. The model application showed a good prediction of all process parameters defined; maximum error between experimental and predicted value was 1.84 % for alkalinity profile. A linear predictive adaptive model for anaerobic digestion of onion waste in a two-stage process was determined under batch-fed condition. Organic load rate (OLR) was maintained constant for the entire operation, modifying effluent hydrolysis reactor feed to UASB reactor. This condition avoids intoxication of UASB reactor and also limits external buffer addition.

Effects of Predation by Protists on Prokaryotic Community Function, Structure, and Diversity in Anaerobic Granular Sludge.

PubMed

Hirakata, Yuga; Oshiki, Mamoru; Kuroda, Kyohei; Hatamoto, Masashi; Kubota, Kengo; Yamaguchi, Takashi; Harada, Hideki; Araki, Nobuo

2016-09-29

Predation by protists is top-down pressure that regulates prokaryotic abundance, community function, structure, and diversity in natural and artificial ecosystems. Although the effects of predation by protists have been studied in aerobic ecosystems, they are poorly understood in anoxic environments. We herein studied the influence of predation by Metopus and Caenomorpha ciliates-ciliates frequently found in anoxic ecosystems-on prokaryotic community function, structure, and diversity. Metopus and Caenomorpha ciliates were cocultivated with prokaryotic assemblages (i.e., anaerobic granular sludge) in an up-flow anaerobic sludge blanket (UASB) reactor for 171 d. Predation by these ciliates increased the methanogenic activities of granular sludge, which constituted 155% of those found in a UASB reactor without the ciliates (i.e., control reactor). Sequencing of 16S rRNA gene amplicons using Illumina MiSeq revealed that the prokaryotic community in the UASB reactor with the ciliates was more diverse than that in the control reactor; 2,885-3,190 and 2,387-2,426 operational taxonomic units (>97% sequence similarities), respectively. The effects of predation by protists in anaerobic engineered systems have mostly been overlooked, and our results show that the influence of predation by protists needs to be examined and considered in the future for a better understanding of prokaryotic community structure and function.

Removal of Total Coliforms, Thermotolerant Coliforms, and Helminth Eggs in Swine Production Wastewater Treated in Anaerobic and Aerobic Reactors

PubMed Central

Zacarias Sylvestre, Silvia Helena; Lux Hoppe, Estevam Guilherme; de Oliveira, Roberto Alves

2014-01-01

The present work evaluated the performance of two treatment systems in reducing indicators of biological contamination in swine production wastewater. System I consisted of two upflow anaerobic sludge blanket (UASB) reactors, with 510 and 209 L in volume, being serially arranged. System II consisted of a UASB reactor, anaerobic filter, trickling filter, and decanter, being also organized in series, with volumes of 300, 190, 250, and 150 L, respectively. Hydraulic retention times (HRT) applied in the first UASB reactors were 40, 30, 20, and 11 h in systems I and II. The average removal efficiencies of total and thermotolerant coliforms in system I were 92.92% to 99.50% and 94.29% to 99.56%, respectively, and increased in system II to 99.45% to 99.91% and 99.52% to 99.93%, respectively. Average removal rates of helminth eggs in system I were 96.44% to 99.11%, reaching 100% as in system II. In reactor sludge, the counts of total and thermotolerant coliforms ranged between 105 and 109 MPN (100 mL)−1, while helminth eggs ranged from 0.86 to 9.27 eggs g−1 TS. PMID:24812560

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

PubMed

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

2013-10-01

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

Removal of slowly biodegradable COD in combined thermophilic UASB and MBBR systems.

PubMed

Ji, M; Yu, J; Chen, H; Yue, P L

2001-09-01

Starch, cellulose and polyvinyl alcohol (PVA) are common substrates of the slowly biodegradable COD (SBCOD) in industrial wastewaters. Removal of the individual and mixed SbCOD substrates was investigated in a combined system of thermophilic upflow anaerobic sludge blanket (TUASB) reactor (55 degrees C) and aerobic moving bed biofilm reactor (MBBR). The removal mechanisms of the three SBCOD substrates were quite different. Starch-COD was almost equally utilized and removed in the two reactors. Cellulose-COD was completely (97-98%) removed from water in the TUASB reactor by microbial entrapment and sedimentation of the cellulose fibers. PVA alone was hardly biodegraded and removed by the combined reactors. However, PVA-COD could be removed to some extent in a binary solution of starch (77%) plus PVA (23%). The PVA macromolecules in the binary solution actually affected the microbial activity in the TUASB reactor resulting accumulation of volatile fatty acids, which shifted the overall COD removal from the TUASB to the MBBR reactor where SBCOD including PVA-COD was removed. Since the three SBCOD substrates were removed by different mechanisms, the combined reactors showed a better and more stable performance than individual reactors.

Microbial monitoring of ammonia removal in a UASB reactor treating pre-digested chicken manure with anaerobic granular inoculum.

PubMed

Yangin-Gomec, Cigdem; Pekyavas, Goksen; Sapmaz, Tugba; Aydin, Sevcan; Ince, Bahar; Akyol, Çağrı; Ince, Orhan

2017-10-01

Performance and microbial community dynamics in an upflow anaerobic sludge bed (UASB) reactor coupled with anaerobic ammonium oxidizing (Anammox) treating diluted chicken manure digestate (Total ammonia nitrogen; TAN=123±10mg/L) were investigated for a 120-d operating period in the presence of anaerobic granular inoculum. Maximum TAN removal efficiency reached to above 80% with as low as 20mg/L TAN concentrations in the effluent. Moreover, total COD (tCOD) with 807±215mg/L in the influent was removed by 60-80%. High-throughput sequencing revealed that Proteobacteria, Actinobacteria, and Firmicutes were dominant phyla followed by Euryarchaeota and Bacteroidetes. The relative abundance of Planctomycetes significantly increased from 4% to 8-9% during the late days of the operation with decreased tCOD concentration, which indicated a more optimum condition to favor ammonia removal through anammox route. There was also significant association between the hzsA gene and ammonia removal in the UASB reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of an up-flow anaerobic sludge bed (UASB) reactor containing diatomite and maifanite for the improved treatment of petroleum wastewater.

PubMed

Chen, Chunmao; Liang, Jiahao; Yoza, Brandon A; Li, Qing X; Zhan, Yali; Wang, Qinghong

2017-11-01

Novel diatomite (R1) and maifanite (R2) were utilized as support materials in an up-flow anaerobic sludge bed (UASB) reactor for the treatment of recalcitrant petroleum wastewater. At high organic loadings (11kg-COD/m 3 ·d), these materials were efficient at reducing COD (92.7% and 93.0%) in comparison with controls (R0) (88.4%). Higher percentages of large granular sludge (0.6mm or larger) were observed for R1 (30.3%) and R2 (24.6%) compared with controls (22.6%). The larger portion of granular sludge provided a favorable habitat that resulted in greater microorganism diversity. Increased filamentous bacterial communities are believed to have promoted granular sludge formation promoting a conductive environment for stimulation methanogenic Archaea. These communities had enhanced pH tolerance and produced more methane. This study illustrates a new potential use of diatomite and maifanite as support materials in UASB reactors for increased efficiency when treating refractory wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anaerobic degradation of coconut husk leachate using UASB-reactor.

PubMed

Neena, C; Ambily, P S; Jisha, M S

2007-07-01

Reffing of coconut husk, the majorprocess in quality coir fibre extraction, causes serious pollution with brackish water lagoons of Kerala. An attempt is made to treat the coconut husk leachate by using a laboratory scale UASB-reactor The experiment was conducted with loading of leachate from 1 kg of fresh coconut husk. The anaerobic treatment was done continuously The parameters like VFA, pH, COD and polyphenols were analysed regularly during the evaluation of the reactor performance. The polyphenol, VFA and COD were diminished gradually with time. The pH of the reactor during the study was found to be in the range of 6-8. The biogas production was increased with loading and about 82% of the total COD/kg husk could be converted to biogas. The maximum polyphenol loading in the reactor was reached to about 298.51 mg/l of husk.

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

PubMed Central

Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

2005-01-01

This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. PMID:16122390

Kinetic of carbonaceous substrate in an upflow anaerobic sludge sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP).

PubMed

Sponza, Delia Teresa; Uluköy, Ayşen

2008-01-01

The performance of an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP) was evaluated at different hydraulic retention times (HRTs) using synthetic wastewater in order to obtain the growth substrate (glucose-COD) and 2,4 DCP removal kinetics. Treatment efficiencies of the UASB reactor were investigated at different hydraulic retention times (2-20 h) corresponding to a food to mass (F/M) ratio of 1.2-1.92 g-COD g(-1) VSS day(-1). A total of 65-83% COD removal efficiencies were obtained at HRTs of 2-20 h. In all, 83% and 99% 2,4 DCP removals were achieved at the same HRTs in the UASB reactor. Conventional Monod, Grau Second-order and Modified Stover-Kincannon models were applied to determine the substrate removal kinetics of the UASB reactor. The experimental data obtained from the kinetic models showed that the Monod kinetic model is more appropriate for correlating the substrate removals compared to the other models for the UASB reactor. The maximum specific substrate utilization rate (k) (mg-COD mg(-1) SS day(-1)), half-velocity concentration (K(s)) (mg COD l(-1)), growth yield coefficient (Y) (mg mg(-1)) and bacterial decay coefficient (b) (day(-1)) were 0.954 mg-COD mg(-1) SS day(-1), 560.29 mg-COD l(-1), 0.78 mg-SS g(-1)-COD, 0.093 day(-1) in the Conventional Monod kinetic model. The second-order kinetic coefficient (k(2)) was calculated as 0.26 day(-1) in the Grau reaction kinetic model. The maximum COD removal rate constant (U(max)) and saturation value (K(B)) were calculated as 7.502 mg CODl(-1)day(-1) and 34.56 mg l(-1)day(-1) in the Modified Stover-Kincannon Model. The (k)(mg-2,4 DCP mg(-1) SS day(-1)), (K(s)) (mg 2,4 DCPl(-1)), (Y) (mg SS mg(-1) 2,4 DCP) and (k(d)) (day(-1)) were 0.0041 mg-2,4 DCP mg(-1) SS day(-1), 2.06 mg-COD l(-1), 0.0017 mg-SS mg(-1) 2,4 DCP and 3.1 x 10(-5) day(-1) in the Conventional Monod kinetic model for 2,4 DCP degradation. The second-order kinetic coefficient (k(2)) was calculated as 0.30 day(-1) in the Grau reaction kinetic model. The maximum 2,4 DCP removal rate constant (U(max)) and saturation value (K(B)) were calculated as 0.01 mg COD l(-1) day(-1) and 9.8 x 10(-3) mg l(-1) day(-1) in the Modified Stover-Kincannon model.

Comparison of simple, small, full-scale sewage treatment systems in Brazil: UASB-maturation ponds-coarse filter; UASB-horizontal subsurface-flow wetland; vertical-flow wetland (first stage of French system).

PubMed

von Sperling, M

2015-01-01

This paper presents a comparison between three simple sewage treatment lines involving natural processes: (a) upflow anaerobic sludge blanket (UASB) reactor-three maturation ponds in series-coarse rock filter; (b) UASB reactor-horizontal subsurface-flow constructed wetland; and (c) vertical-flow constructed wetlands treating raw sewage (first stage of the French system). The evaluation was based on several years of practical experience with three small full-scale plants receiving the same influent wastewater (population equivalents of 220, 60 and 100 inhabitants) in the city of Belo Horizonte, Brazil. The comparison included interpretation of concentrations and removal efficiencies based on monitoring data (organic matter, solids, nitrogen, phosphorus, coliforms and helminth eggs), together with an evaluation of practical aspects, such as land and volume requirements, sludge production and handling, plant management, clogging and others. Based on an integrated evaluation of all aspects involved, it is worth emphasizing that each system has its own specificities, and no generalization can be made on the best option. The overall conclusion is that the three lines are suitable for sewage treatment in small communities in warm-climate regions.

Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

PubMed Central

Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

2017-01-01

This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community. PMID:28300176

Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

NASA Astrophysics Data System (ADS)

Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

2017-03-01

This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community.

Methane and hydrogen sulfide emissions in UASB reactors treating domestic wastewater.

PubMed

Souza, C L; Chernicharo, C A L; Melo, G C B

2012-01-01

The release of CH(4) and H(2)S in UASB reactors was evaluated with the aim to quantify the emissions from the liquid surfaces (three-phase separator and settler compartment) and also from the reactor's discharge hydraulic structures. The studies were carried out in two pilot- (360 L) and one demo-scale (14 m(3)) UASB reactors treating domestic wastewater. As expected, the release rates were much higher across the gas/liquid interfaces of the three-phase separators (5.4-9.7 kg CH(4) m(-2) d(-1) and 23.0-35.8 g S m(-2) d(-1)) as compared with the quiescent settler surfaces (11.0-17.8 g CH(4) m(-2) d(-1) and 0.21 to 0.37 g S m(-2) d(-1)). The decrease of dissolved methane and dissolved hydrogen sulfide was very large in the discharging hydraulic structures very close to the reactor (>60 and >80%, respectively), largely due to the loss to the atmosphere, indicating that the concentration of these compounds will probably fall to values close to zero in the near downstream structures. The emission factors due to the release of dissolved methane in the discharge structure amounted to around 0.040 g CH(4) g COD(infl)(-1) and 0.060 g CH(4) g COD(rem)(-1), representing around 60% of the methane collected in the three-phase separator.

Long-term competition between sulfate reducing and methanogenic bacteria in UASB reactors treating volatile fatty acids.

PubMed

Omil, F; Lens, P; Visser, A; Hulshoff Pol, L W; Lettinga, G

1998-03-20

The competition between acetate utilizing methane-producing bacteria (MB) and sulfate-reducing bacteria (SRB) was studied in mesophilic (30 degrees C) upflow anaerobic sludge bed (UASB) reactors (upward velocity 1 m h-1; pH 8) treating volatile fatty acids and sulfate. The UASB reactors treated a VFA mixture (with an acetate:propionate:butyrate ratio of 5:3:2 on COD basis) or acetate as the sole substrate at different COD:sulfate ratios. The outcome of the competition was evaluated in terms of conversion rates and specific methanogenic and sulfidogenic activities. The COD:sulfate ratio was a key factor in the partitioning of acetate utilization between MB and SRB. In excess of sulfate (COD:sulfate ratio lower than 0.67), SRB became predominant over MB after prolonged reactor operation: 250 and 400 days were required to increase the amount of acetate used by SRB from 50 to 90% in the reactor treating, respectively, the VFA mixture or acetate as the sole substrate. The competition for acetate was further studied by dynamic simulations using a mathematical model based on the Monod kinetic parameters of acetate utilizing SRB and MB. The simulations confirmed the long term nature of the competition between these acetotrophs. A high reactor pH (+/-8), a short solid retention time (<150 days), and the presence of a substantial SRB population in the inoculum may considerably reduce the time required for acetate-utilising SRB to outcompete MB. Copyright 1998 John Wiley & Sons, Inc.

Artificial intelligence based model for optimization of COD removal efficiency of an up-flow anaerobic sludge blanket reactor in the saline wastewater treatment.

PubMed

Picos-Benítez, Alain R; López-Hincapié, Juan D; Chávez-Ramírez, Abraham U; Rodríguez-García, Adrián

2017-03-01

The complex non-linear behavior presented in the biological treatment of wastewater requires an accurate model to predict the system performance. This study evaluates the effectiveness of an artificial intelligence (AI) model, based on the combination of artificial neural networks (ANNs) and genetic algorithms (GAs), to find the optimum performance of an up-flow anaerobic sludge blanket reactor (UASB) for saline wastewater treatment. Chemical oxygen demand (COD) removal was predicted using conductivity, organic loading rate (OLR) and temperature as input variables. The ANN model was built from experimental data and performance was assessed through the maximum mean absolute percentage error (= 9.226%) computed from the measured and model predicted values of the COD. Accordingly, the ANN model was used as a fitness function in a GA to find the best operational condition. In the worst case scenario (low energy requirements, high OLR usage and high salinity) this model guaranteed COD removal efficiency values above 70%. This result is consistent and was validated experimentally, confirming that this ANN-GA model can be used as a tool to achieve the best performance of a UASB reactor with the minimum requirement of energy for saline wastewater treatment.

Gills Onions Advanced Energy Recovery System: Turning a Waste Liability into a Renewable Resource

DTIC Science & Technology

2011-01-13

i U fl A bi 2 rea u ce s ng an p ow naero c Sludge Blanket (UASB) Reactor 3 Recover Biogas from UASB Remove Sulfur and Moisture for Cattle... biogas per cell ● 15 psi ● Requires highly purified water (RO) Energy NG RO W ta er ● Methane and steam converted into hydrogen-rich gas

Immobilization patterns and dynamics of acetate-utilizing methanogens immobilized in sterile granular sludge in upflow anaerobic sludge blanket reactors.

PubMed

Schmidt, J E; Ahring, B K

1999-03-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and mumax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor.

Effect of non-feeding period length on the intermittent operation of UASB reactors treating dairy effluents.

PubMed

Coelho, N M; Rodrigues, A A; Arroja, L M; Capela, I F

2007-02-01

Recent environmental concerns have prompted a re-evaluation of conventional management strategies and refueled the search of innovative waste management practices. In this sense, the anaerobic digestion of both fat and the remaining complex organic matter present in dairy wastewaters is attractive, although the continuous operation of high rate anaerobic processes treating this type of wastewaters causes the failure of the process. This work accesses the influence of non-feeding period length on the intermittent operation of mesophilic UASB reactors treating dairy wastewater, in order to allow the biological degradation to catch up with adsorption phenomenon. During the experiments, two UASB reactors were subject to three organic loading rates, ranging from 6 to 12 g(COD) x L(-1) x d(-1), with the same daily load applied to both reactors, each one with a different non-feeding period. Both reactors showed good COD removal efficiencies (87-92%). A material balance for COD in the reactors during the feeding and non-feeding periods showed the importance of the feedless period, which allowed the biomass to degrade substrate that was accumulated during the feeding period. The reactor with the longest non-feeding period had a better performance, which resulted in a higher methane production and adsorption capacity for the same organic load applied with a consequent less accumulation of substrate into the biomass. In addition, both reactors had a stable operation for the organic load of 12 g(COD) x L(-1) x d(-1), which is higher than the maximum applicable load reported in literature for continuous systems (3-6 g(COD) x L(-1) x d(-1)). (c) 2006 Wiley Periodicals, Inc.

Immobilization Patterns and Dynamics of Acetate-Utilizing Methanogens Immobilized in Sterile Granular Sludge in Upflow Anaerobic Sludge Blanket Reactors

PubMed Central

Schmidt, Jens Ejbye; Ahring, Birgitte Kjær

1999-01-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and μmax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor. PMID:10049862

Studies on the toxic effects of pentachlorophenol on the biological activity of anaerobic granular sludge.

PubMed

Liu, Xin-Wen; He, Ruo; Shen, Dong-Sheng

2008-09-01

In order to explore the pathway of the anaerobic biotreatment of the wastewater containing pentachlorophenol (PCP) and ensure the normal operation of Upflow Anaerobic Sludge Blanket (UASB) reactor, the anaerobic sludge under different acclimation conditions were selected to seed and start up UASB reactors. Anaerobic toxicity assays were employed to study the biological activity, the tolerance and the capacity to degrade PCP of different anaerobic granular sludge from UASB reactors. Results showed that the anaerobic granular sludge acclimated to chlorophenols (CPs) could degrade PCP more quickly (up to 9.50mg-PCP g(-1)TVS d(-1)). And the anaerobic granular sludge without acclimation to CPs had only a little activity of degrading PCP (less than 0.07 mg-PCP g(-1)TVS d(-1)). Different PCP concentrations (2, 4, 6, 8 mg L(-1)) had different inhibition effects on glucose utilization, volatile fatted acidity (VFA)-degrading and methanogens activity of PCP degradation anaerobic granular sludge, and the biological activity declined with the increase in PCP concentration. The methanogens activity suffered inhibition from PCP more easily. The different acclimation patterns of seeded sludge had distinctly different effects on biological activity of the degradation of PCP of anaerobic granular sludge from UASB reactors. The biological activity of the anaerobic granular sludge acclimated to PCP only was also inhibited. This inhibition was weak compared to that of anaerobic granular sludge acclimated to CPs, further, the activity could recover more quickly in this case. In the same reactor, the anaerobic granular sludge from the mid and base layers showed higher tolerance to PCP than that from super layer or if the sludge is unacclimated to CPs, and the corresponding recovery time of the biological activity in the mid and base layers were short. Acetate-utilizing methanogens and syntrophic propinate degraders were sensitive to PCP, compared to syntrophic butyrate degraders.

Mesophilic biomethanation and treatment of poultry waste-water using pilot scale UASB reactor.

PubMed

Atuanya, Ernest I; Aigbirior, Moses

2002-07-01

The feasibility of applying the up-flow anaerobic sludge blanket (UASB) treatment for poultry waste (faeces) water was examined. A continuous-flow UASB pilot scale reactor of 3.50 L capacity using mixed culture was operated for 95 days to assess the treatability of poultry waste-water and its methane production. The maximum chemical oxygen demand (COD) removed was found to be 78% when organic loading rate (OLR) was 2.9 kg COD m(-3) day(-1) at hydraulic retention times (HRT) of 13.2 hr. The average biogas recovery was 0.26 m3 CH4 kg COD with an average methane content of 57% at mean temperature of 30 degrees C. Data indicate more rapid methanogenesis with higher loading rates and shorter hydraulic retention times. At feed concentration of 4.8 kg COD m(-3) day(-1), anaerobic digestion was severely retarded at all hydraulic retention time tested. This complication in the reactor operations may be linked to build-up of colloidal solids often associated with poultry waste water and ammonia toxicity. Isolates from granular sludge and effluent were found to be facultative anaerobes most of which were Pseudomonas genera.

Influence of a three-phase separator configuration on the performance of an upflow anaerobic sludge bed reactor treating wastewater from a fruit-canning factory.

PubMed

Wongnoi, Rachbordin; Songkasiri, Warinthorn; Phalakornkule, Chantaraporn

2007-02-01

The objective of this study was to investigate the influence of a three-phase separator configuration on the performance of an upflow anaerobic sludge bed (USAB) treating wastewater from a fruit canning factory. The performances of two 30-L UASB reactors--one with a modified three-phase separator giving a spiral flow pattern and the other with a conventional configuration-were investigated in parallel. Wastewater, with a chemical oxygen demand (COD) concentration between 2000 and 7000 mg/L, was obtained from a fruit-canning factory. Based on the effluent data of the first 100 operation days, the UASB with the three-phase separator giving spiral flow patterns yielded up to 25% lower biomass washout. It also showed better efficiencies in treating wastewater--up to 60% lower effluent COD, up to 20% higher COD percent removal, and up to 29% higher biogas production. This work presents evidence of an improvement on the conventional physical design of a UASB.

Anaerobic on-site treatment of black water and dairy parlour wastewater in UASB-septic tanks at low temperatures.

PubMed

Luostarinen, Sari A; Rintala, Jukka A

2005-01-01

Anaerobic on-site treatment of synthetic black water (BW) and dairy parlour wastewater (DPWW) was studied in two-phased upflow anaerobic sludge blanket (UASB)-septic tanks at low temperatures (10-20 degrees C). At all temperatures, total chemical oxygen demand (COD(t)) removal was above 90% with BW and above 80% with DPWW and removal of total suspended solids (TSS) above 90% with both wastewaters. Moreover, dissolved COD (COD(dis)) removal was approx. 70% with both wastewaters indicating good biological activity of the sludges. With BW, a single-phased reactor was found sufficient for good COD removals, while with DPWW, a two-phased process was required. Temperature optimum of reactor sludges was still 35 degrees C after long (398d) operation. Most of the nutrients from BW were removed with TSS, while with DPWW nutrient removal was low. In conclusion, UASB-septic tank was found feasible for (pre)treatment of BW and DPWW at low temperatures.

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors.

PubMed

Tham, P T Pham thi; Kennedy, K J Kevin J

2004-05-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000-12,000mg/L COD), 12-56h HRT, and 18-36gVSS/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal efficiency, biomass-specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time, and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass-specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass-specific acetoclastic activity was improved two-fold from 0.23gCOD/gVSS/d for inoculum to a maximum of 0.55gCOD/gVSS/d during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. The predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate is increased. ADF toxicity effects were evident for 1.6% ADF at medium organic loadings (SOLR above 0.5gCOD/gVSS/d). In contrast, good reactor stability and excellent COD removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73gCOD/gVSS/d).

Response of Syntrophic Propionate Degradation to pH Decrease and Microbial Community Shifts in an UASB Reactor.

PubMed

Zhang, Liguo; Ban, Qiaoying; Li, Jianzheng; Jha, Ajay Kumar

2016-08-28

The effect of pH on propionate degradation in an upflow anaerobic sludge blanket (UASB) reactor containing propionate as a sole carbon source was studied. Under influent propionate of 2,000 mg/l and 35ºC, propionate removal at pH 7.5-6.8 was above 93.6%. Propionate conversion was significantly inhibited with stepwise pH decrease from pH 6.8 to 6.5, 6.0, 5.5, 5.0, 4.5, and then to 4.0. After long-term operation, the propionate removal at pH 6.5-4.5 maintained an efficiency of 88.5%-70.1%, whereas propionate was hardly decomposed at pH 4.0. Microbial composition analysis showed that propionate-oxidizing bacteria from the genera Pelotomaculum and Smithella likely existed in this system. They were significantly reduced at pH ≤5.5. The methanogens in this UASB reactor belonged to four genera: Methanobacterium, Methanospirillum, Methanofollis, and Methanosaeta. Most detectable hydrogenotrophic methanogens were able to grow at low pH conditions (pH 6.0-4.0), but the acetotrophic methanogens were reduced as pH decreased. These results indicated that propionate-oxidizing bacteria and acetotrophic methanogens were more sensitive to low pH (5.5-4.0) than hydrogenotrophic methanogens.

Wastewater infrastructure for small cities in an urbanizing world: integrating protection of human health and the environment with resource recovery and food security.

PubMed

Verbyla, Matthew E; Oakley, Stewart M; Mihelcic, James R

2013-04-16

The majority of population growth in developing countries will occur in small cities closely linked to agricultural zones, with poor access to water and sanitation. Wastewater management priorities in these regions will be different from those in larger cities and developed countries. Two wastewater treatment systems in Bolivia, one with an upflow anaerobic sludge blanket (UASB) reactor and polishing ponds, the other with three stabilization ponds, are assessed to determine their resource recovery potential. The UASB reactor produces biogas with 500-650 MJ per day. In six months, both systems discharge wastewater with the same mass of nutrients as fertilizers used to produce crops containing 10-75 days' worth of the recommended food energy intake for each person using the system. Both systems also discharge detectable levels of helminth eggs, Giardia cysts, and Cryptosporidium oocysts, but the UASB reactor system discharges higher concentrations, implying limited reuse potential. From a regional management standpoint, small cities should not expend resources to treat wastewater to levels suitable for discharge into surface waters. Rather, they should focus on removing pathogens to reclaim water and nutrients. Biogas recovery may be a priority that should be subservient to water and nutrient recovery in these settings.

A case study of enteric virus removal and insights into the associated risk of water reuse for two wastewater treatment pond systems in Bolivia.

PubMed

Symonds, E M; Verbyla, M E; Lukasik, J O; Kafle, R C; Breitbart, M; Mihelcic, J R

2014-11-15

Wastewater treatment ponds (WTP) are one of the most widespread treatment technologies in the world; however, the mechanisms and extent of enteric virus removal in these systems are poorly understood. Two WTP systems in Bolivia, with similar overall hydraulic retention times but different first stages of treatment, were analyzed for enteric virus removal. One system consisted of a facultative pond followed by two maturation ponds (three-pond system) and the other consisted of an upflow anaerobic sludge blanket (UASB) reactor followed by two maturation (polishing) ponds (UASB-pond system). Quantitative polymerase chain reaction with reverse transcription (RT-qPCR) was used to measure concentrations of norovirus, rotavirus, and pepper mild mottle virus, while cell culture methods were used to measure concentrations of culturable enteroviruses (EV). Limited virus removal was observed with RT-qPCR in either system; however, the three-pond system removed culturable EV with greater efficiency than the UASB-pond system. The majority of viruses were not associated with particles and only a small proportion was associated with particles larger than 180 μm; thus, it is unlikely that sedimentation is a major mechanism of virus removal. High concentrations of viruses were associated with particles between 0.45 and 180 μm in the UASB reactor effluent, but not in the facultative pond effluent. The association of viruses with this size class of particles may explain why only minimal virus removal was observed in the UASB-pond system. Quantitative microbial risk assessment of the treated effluent for reuse for restricted irrigation indicated that the three-pond system effluent requires an additional 1- to 2-log10 reduction of viruses to achieve the WHO health target of <10(-4) disability-adjusted life years (DALYs) lost per person per year; however, the UASB-pond system effluent may require an additional 2.5- to 4.5-log10 reduction of viruses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved methane production from sugarcane vinasse with filter cake in thermophilic UASB reactors, with predominance of Methanothermobacter and Methanosarcina archaea and Thermotogae bacteria.

PubMed

Barros, Valciney Gomes de; Duda, Rose Maria; Vantini, Juliana da Silva; Omori, Wellington Pine; Ferro, Maria Inês Tiraboschi; Oliveira, Roberto Alves de

2017-11-01

Biogas production from sugarcane vinasse has enormous economic, energy, and environmental management potential. However, methane production stability and biodigested vinasse quality remain key issues, requiring better nutrient and alkalinity availability, operational strategies, and knowledge of reactor microbiota. This study demonstrates increased methane production from vinasse through the use of sugarcane filter cake and improved effluent recirculation, with elevated organic loading rates (OLR) and good reactor stability. We used UASB reactors in a two-stage configuration, with OLRs up to 45gCODL -1 d -1 , and obtained methane production as high as 3LL -1 d -1 . Quantitative PCR indicated balanced amounts of bacteria and archaea in the sludge (10 9 -10 10 copiesg -1 VS), and of the predominant archaea orders, Methanobacteriales and Methanosarcinales (10 6 -10 8 copiesg -1 VS). 16S rDNA sequencing also indicated the thermophilic Thermotogae as the most abundant class of bacteria in the sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of biogas sparging on the performance of bio-hydrogen reactor over a long-term operation.

PubMed

Nualsri, Chatchawin; Kongjan, Prawit; Reungsang, Alissara; Imai, Tsuyoshi

2017-01-01

This study aimed to enhance hydrogen production from sugarcane syrup by biogas sparging. Two-stage continuous stirred tank reactor (CSTR) and upflow anaerobic sludge blanket (UASB) reactor were used to produce hydrogen and methane, respectively. Biogas produced from the UASB was used to sparge into the CSTR. Results indicated that sparging with biogas increased the hydrogen production rate (HPR) by 35% (from 17.1 to 23.1 L/L.d) resulted from a reduction in the hydrogen partial pressure. A fluctuation of HPR was observed during a long term monitoring because CO2 in the sparging gas and carbon source in the feedstock were consumed by Enterobacter sp. to produce succinic acid without hydrogen production. Mixed gas released from the CSTR after the sparging can be considered as bio-hythane (H2+CH4). In addition, a continuous sparging biogas into CSTR release a partial pressure in the headspace of the methane reactor. In consequent, the methane production rate is increased.

Effect of biogas sparging on the performance of bio-hydrogen reactor over a long-term operation

PubMed Central

Nualsri, Chatchawin; Kongjan, Prawit; Imai, Tsuyoshi

2017-01-01

This study aimed to enhance hydrogen production from sugarcane syrup by biogas sparging. Two-stage continuous stirred tank reactor (CSTR) and upflow anaerobic sludge blanket (UASB) reactor were used to produce hydrogen and methane, respectively. Biogas produced from the UASB was used to sparge into the CSTR. Results indicated that sparging with biogas increased the hydrogen production rate (HPR) by 35% (from 17.1 to 23.1 L/L.d) resulted from a reduction in the hydrogen partial pressure. A fluctuation of HPR was observed during a long term monitoring because CO2 in the sparging gas and carbon source in the feedstock were consumed by Enterobacter sp. to produce succinic acid without hydrogen production. Mixed gas released from the CSTR after the sparging can be considered as bio-hythane (H2+CH4). In addition, a continuous sparging biogas into CSTR release a partial pressure in the headspace of the methane reactor. In consequent, the methane production rate is increased. PMID:28207755

Antibiotic Fermentation Broth Treatment by a pilot upflow anaerobic sludge bed reactor and kinetic modeling.

PubMed

Coskun, T; Kabuk, H A; Varinca, K B; Debik, E; Durak, I; Kavurt, C

2012-10-01

In this study, an upflow anaerobic sludge blanket (UASB) mesophilic reactor was used to remove antibiotic fermentation broth wastewater. The hydraulic retention time was held constant at 13.3 days. The volumetric organic loading value increased from 0.33 to 7.43 kg(COD)m(-3)d(-1) using antibiotic fermentation broth wastewater gradually diluted with various ratios of domestic wastewater. A COD removal efficiency of 95.7% was obtained with a maximum yield of 3,700 L d(-1) methane gas production. The results of the study were interpreted using the modified Stover-Kincannon, first-order, substrate mass balance and Van der Meer and Heertjes kinetic models. The obtained kinetic coefficients showed that antibiotic fermentation broth wastewater can be successfully treated using a UASB reactor while taking COD removal and methane production into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

A two-stage aerobic/anaerobic denitrifying horizontal bioreactor designed for treating ammonium and H(2)S simultaneously.

PubMed

Chinalia, F A; Garbossa, L H P; Rodriguez, J A; Lapa, K R; Foresti, E

2012-11-01

A two-stage bioreactor was operated for a period of 140 days in order to develop a post-treatment process based on anaerobic bioxidation of sulfite. This process was designed for simultaneously treating the effluent and biogas of a full-scale UASB reactor, containing significant concentrations of NH(4) and H(2)S, respectively. The system comprised of two horizontal-flow bed-packed reactors operated with different oxygen concentrations. Ammonium present in the effluent was transformed into nitrates in the first aerobic stage. The second anaerobic stage combined the treatment of nitrates in the liquor with the hydrogen sulfide present in the UASB-reactor biogas. Nitrates were consumed with a significant production of sulfate, resulting in a nitrate removal rate of 0.43 kgNm(3)day(-1) and ≥92 % efficiency. Such a removal rate is comparable to those achieved by heterotrophic denitrifying systems. Polymeric forms of sulfur were not detected (elementary sulfur); sulfate was the main product of the sulfide-based denitrifying process. S-sulfate was produced at a rate of about 0.35 kgm(3)day(-1). Sulfur inputs as S-H(2)S were estimated at about 0.75 kgm(3)day(-1) and Chemical Oxygen Demand (COD) removal rates did not vary significantly during the process. DGGE profiling and 16S rRNA identified Halothiobacillus-like species as the key microorganism supporting this process; such a strain has not yet been previously associated with such bioengineered systems.

[Treatment of ANAMMOX technique on treating high concentration poultry wastewater].

PubMed

Zhu, Jie; Huang, Tao; Fan, Xing-Jian; Zhang, Cheng-Fu

2009-05-15

Taking the effluent of the UASB-shortcut nitrification technique of typical high concentration poultry wastewater as the object, it is discussed that the ANAMMOX is applicable as a treatment of denitrification. Firstly, it successfully starts ANAMMOX reactor by the denitrifying activated sludge, on this basis, finding the optimal ammonia loading is about 0.2 kg/(m3 x d) and the HRT of system is 2 d. Moreover, after studyingon the operating conditions, the optimum is that pH is about 7.50; temperature is 30 degrees C without adding organic carbon. Under optimum conditions, the removal efficiencies of ammonia and nitrite nitrogen could be above 85% and 95%, the system is running well and has reproducibility. Finally, it reaches that the reaction rates of ammonia and nitrite nitrogen are 0.0126 d(-1) and 0.0131 d(-1) through dynamic analysis. So it can make the theory basis for spreading and application of after/continuous process, neural network simulation and "UASB + SBR shortcut nitrification + ANAMMOX + land treating system" newly combined process.

Microbial community dynamics and biogas production from manure fractions in sludge bed anaerobic digestion.

PubMed

Nordgård, A S R; Bergland, W H; Bakke, R; Vadstein, O; Østgaard, K; Bakke, I

2015-12-01

To elucidate how granular sludge inoculum and particle-rich organic loading affect the structure of the microbial communities and process performance in upflow anaerobic sludge bed (UASB) reactors. We investigated four reactors run on dairy manure filtrate and four on pig manure supernatant for three months achieving similar methane yields. The reactors fed with less particle rich pig manure stabilized faster and had highest capacity. Microbial community dynamics analysed by a PCR/denaturing gradient gel electrophoresis approach showed that influent was a major determinant for the composition of the reactor communities. Comparisons of pre- and non-adapted inoculum in the reactors run on pig manure supernatant showed that the community structure of the nonadapted inoculum adapted in approximately two months. Microbiota variance partitioning analysis revealed that running time, organic loading rate and inoculum together explained 26 and 31% of the variance in bacterial and archaeal communities respectively. The microbial communities of UASBs adapted to the reactor conditions in treatment of particle rich manure fractions, obtaining high capacity, especially on pig manure supernatant. These findings provide relevant insight into the microbial community dynamics in startup and operation of sludge bed reactors for methane production from slurry fractions, a major potential source of biogas. © 2015 The Society for Applied Microbiology.

Novel online monitoring and alert system for anaerobic digestion reactors.

PubMed

Dong, Fang; Zhao, Quan-Bao; Li, Wen-Wei; Sheng, Guo-Ping; Zhao, Jin-Bao; Tang, Yong; Yu, Han-Qing; Kubota, Kengo; Li, Yu-You; Harada, Hideki

2011-10-15

Effective monitoring and diagnosis of anaerobic digestion processes is a great challenge for anaerobic digestion reactors, which limits their stable operation. In this work, an online monitoring and alert system for upflow anaerobic sludge blanket (UASB) reactors is developed on the basis of a set of novel evaluating indexes. The two indexes, i.e., stability index S and auxiliary index a, which incorporate both gas- and liquid-phase parameters for UASB, enable a quantitative and comprehensive evaluation of reactor status. A series of shock tests is conducted to evaluate the response of the monitoring and alert system to organic overloading, hydraulic, temperature, and toxicant shocks. The results show that this system enables an accurate and rapid monitoring and diagnosis of the reactor status, and offers reliable early warnings on the potential risks. As the core of this system, the evaluating indexes are demonstrated to be of high accuracy and sensitivity in process evaluation and good adaptability to the artificial intelligence and automated control apparatus. This online monitoring and alert system presents a valuable effort to promote the automated monitoring and control of anaerobic digestion process, and holds a high promise for application.

UASB-septic tank as an alternative for decentralized wastewater treatment in Mexico.

PubMed

Santiago-Díaz, Ángel L; García-Albortante, Julisa; Salazar-Peláez, Mónica L

2018-02-05

The aim of this work was to evaluate the performance of a UASB-septic tank as a decentralized treatment of high-strength municipal wastewater under two different HRTs (48 and 72 h). Thus, a lab-scale (44.85 L) UASB-septic tank constituted by three compartments was operated under HRT 72 and 48 h. Removal efficiencies of total chemical oxygen demand (COD), biological oxygen demand (BOD 5 ) and suspended solids (SS) ranged from 60% to 80% for the first two parameters and from 70% to 90% for the last one. According to the statistical analysis, it was established that decreasing HRT from 72 to 48 h did not affect the performance of the UASB-septic tank; therefore, the latter HRT is recommended to be used for operation. In the first compartment, most of the organic matter removal was carried out, while the other two compartments served as polishing. Over the course of six months, the VS concentration and VS/TS ratio in sludge blanket decreased, indicating digestion and stabilization of the retained solids. Also, an increase of 4% in sludge volume was observed; thus, time for desludging would be approximately five years. Comparison of the UASB-septic tank and the UASB reactor showed that both systems had similar performance regarding effluent concentrations of organic matter and solids. Thus, under low volumetric organic load conditions (less than 20 mg COD/L h), the former is an attractive option for municipal wastewater treatment.

Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors

PubMed Central

Fermoso, Fernando G.; Collins, Gavin; Bartacek, Jan; O’Flaherty, Vincent

2008-01-01

The effect of nickel deprivation from the influent of a mesophilic (30°C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5–15 g COD l−1 day−1 for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (±0.167) g CH4-COD g VSS−1 day−1 compared to 2.027 (±0.111) g CH4-COD g VSS−1 day−1 in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 μM Ni (dosed as NiCl2) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation. PMID:18247139

[Air stripping-UASB process for the treatment of evaporator condensate from a Kraft pulp mill].

PubMed

Zhou, Wei-li; Qin, Xiao-peng; Yu, Jun; Imai, Tsuyoshi; Ukita, Masao

2006-04-01

Evaporator condensate from a kraft pulp mill is characterized by high temperature, high strength, poor nutrition, and some odor and inhibitive materials. In this study, air stripping-UASB process was developed to treat the wastewater from a kraft pulp mill. The lab scale study demonstrated that air stripping process removed 70%-80% of the volatile organic sulfur compounds. After that, the UASB reactor showed high efficiency, at the organic loading rate (COD) of 30 kg x (m3 x d)(-1), COD removal was retained about 95%. On the other hand, the inoculated granules were broken in the new surroundings and were replaced with the newly formed granules The scanning electronic microscope (SEM) observation showed wide difference of the predominant anaerobic microorganisms in the seed and newly formed granules.

A combined upflow anaerobic sludge bed and trickling biofilter process for the treatment of swine wastewater.

PubMed

Zhao, Bowei; Li, Jiangzheng; Buelna, Gerardo; Dubé, Rino; Le Bihan, Yann

2016-01-01

A combined upflow anaerobic sludge blanket (UASB)-trickling biofilter (TBF) process was constructed to treat swine wastewater, a typical high-strength organic wastewater with low carbon/nitrogen ratio and ammonia toxicity. The results showed that the UASB-TBF system can remarkably enhance the removal of pollutants in the swine wastewater. At an organic loading rate of 2.29 kg/m(3) d and hydraulic retention time of 48 h in the UASB, the chemical oxygen demand (COD), Suspended Solids and Total Kjeldahl Nitrogen removals of the combined process reached 83.6%, 84.1% and 41.2%, respectively. In the combined system the UASB served as a pretreatment process for COD removal while nitrification and denitrification occurred only in the TBF process. The TBF performed reasonably well at a surface hydraulic load as high as 0.12 m(3)/m(2) d. Since the ratio of influent COD to total mineral nitrogen was less than 3.23, it is reasonable to suggest that the wood chips in TBF can serve as a new carbon source for denitrification.

Simultaneous carbon and nitrogen removal from anaerobic effluent of the cassava ethanol industry.

PubMed

Yin, Zhixuan; Xie, Li; Zhou, Qi; Bi, Xuejun

2018-03-01

This study investigated the simultaneous carbon and nitrogen removal from anaerobic effluent of cassava stillage using a lab-scale integrated system consisting of an upflow anaerobic sludge blanket (UASB) reactor and an activated sludge (AS) process. Simultaneous denitrification and methanogenesis (SDM) was observed in the UASB with nitrate recirculation. Compared with the blank reactor without recirculation, the overall chemical oxygen demand (COD) removal efficiencies in the combined system with nitrate recirculation were similar (80-90%), while the TN removal efficiencies were significantly improved from 4.7% to 71.0%. Additionally, the anaerobic COD removal efficiencies increased from 21% to 40% as the recirculation ratio decreased from 3 to 1. Although the influent nitrate concentrations fluctuated (60-140 mg N/L), the nitrate removal efficiencies could be maintained at about 97% under different recirculation conditions. With the decreasing recirculation ratio from 3 to 1, the CH 4 content in biogas improved from 2% to 40% while the N 2 content reduced from 95.8% to 50.6%. The 16S rDNA sequencing results indicated that bacteria diversity in anaerobic SDM granular sludge was much higher than archaea. The effect of recirculation ratios on the bacterial and archaeal communities in SDM granular sludge could be further confirmed by the relative abundance of denitrifying bacteria. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Influence of sludge reflux ratios on biodegradation performance in a coupled landfill leachate treatment process based on UASB and submerged MBR.

PubMed

Wang, Bing; Li, Wei; Liu, Lei; Huang, Guo He

2016-07-28

This study was undertaken to investigate the effects of different sludge reflux ratios (SRRs) on the overall performance and the fouling behavior of the up-flow anaerobic sludge blanket (UASB) reactor-anoxic-membrane bioreactor (MBR). The leachate and synthetic municipal wastewater were mixed in order to improve the biodegradability of the old leachate. Results showed that excellent removal efficiencies for chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) were obtained by using the integrated UASB-anoxic-MBR process. The average COD removals were 91.01%, 93.90%, and 92.67% and that of NH3-N were 98.1%, 98.5%, and 98.9% when SRRs were 100%, 300%, and 500%, respectively. The study of the membrane fouling mechanism indicated that proteins, hydrocarbons and inorganic matter are the main elements of the cake layers.

Anaerobic degradation of aircraft deicing fluid (ADF) in upflow anaerobic sludge blanket (UASB) reactors and the fate of ADF additives

NASA Astrophysics Data System (ADS)

Pham, Thi Tham

2002-11-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time (HRT), and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass specific acetoclastic activity was improved by almost two-fold during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. Predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate (OLR) was increased. ADF toxicity effects were evident for 1.6% ADF at medium specific organic loadings (SOLR above 0.5 g COD/g VSS/d). In contrast, good reactor stability and excellent removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73 g COD/g VSS/d). Acclimation to ADF resulted in an initial reduction in the biomass settling velocity. The fate of ADF additives was also investigated. There was minimal sorption of benzotriazole (BT), 5-methyl-1 H-benzotriazole (MeBT), and 5,6-dimethyl-1 H-benzotriazole (DiMeBT) to anaerobic granules. A higher sorption capacity was measured for NP. Active transport may be one of the mechanisms for NP sorption. Ethylene glycol degradation experiments indicated that BT, MeBT, DiMeBT, and the nonionic surfactant Tergitol NP-4 had no significant effects on acidogenesis and methanogenesis at the concentration levels studied. A significant inhibition of acetoclastic activity was observed for NP at 100 mg/L, with acetic acid consumption rate at 38% of that for controls. No evidence for anaerobic degradation of benzotriazole and its derivatives was observed; however, both batch and continuous experiments suggested that anaerobic degradation of NP occurred. Kinetic analysis of operational data obtained for the anaerobic treatment of ADF in UASB reactors indicated that the substrate utilization rate was independent of the reactor biomass concentration. The maximum rate of substrate utilization and the half-velocity constants for ADF treatment were 28.4 g COD/L/d and 648 mg COD/L, respectively. For 1.2% ADF, the biomass yield and endogenous decay coefficients were 0.027 g VSS/g COD and 0.012 d-1 , respectively.

Continuous treatment of N-Methyl-p-nitro aniline (MNA) in an Upflow Anaerobic Sludge Blanket (UASB) bioreactor

PubMed Central

Olivares, Christopher I.; Wang, Junqin; Silva Luna, Carlos D.; Field, Jim A.; Abrell, Leif; Sierra-Alvarez, Reyes

2017-01-01

N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to, a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized, however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d-1). Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA. PMID:26454121

Kinetics of methane production and biodegradation of linear alkylbenzene sulfonate from laundry wastewater.

PubMed

Motteran, Fabrício; Braga, Juliana K; Silva, Edson L; Varesche, Maria Bernadete A

2016-12-05

This study evaluates the kinetics of methane production and degradation of standard linear alkylbenzene sulfonate (LAS) (50 ± 3.5 mg/L) and LAS from laundry wastewater (85 ± 2.1 mg/L) in anaerobic batch reactors at 30°C with different sources of inoculum. The inocula were obtained by auto-fermentation (AFM) and UASB reactors from wastewater treatment of poultry slaughterhouse (SGH), swine production (SWT) and wastewater treatment thermophilic of sugarcane industry (THR). The study was divided into three phases: synthetic substrate (Phase I), standard LAS (Phase II) and LAS from laundry wastewater (Phase III). For SGH, the highest values for cumulative methane productions (1,844.8 ± 149 µmol-Phase II), methane production rate (70.8 ± 88 µmol/h-Phase II and 4.01 ± 07 µmol/h-Phase III) were observed. The use of thermophilic biomass (THR) incubated at 30°C was not favorable for methane production and LAS biodegradation, but the highest kinetic coefficient degradation (k 1 app ) was obtained for LAS (0.33 ± 0.3 h) compared with mesophilic biomass (SGH and SWT) (0.13 ± 0.02 h). Therefore, both LAS sources influenced the kinetics of methane production and organic matter degradation. For SGH, inoculum obtained the highest LAS degradation. In the SGH inoculum sequenced by MiSeq-Illumina was identified genera (VadinCA02, Candidatus Cloacamonas, VadinHB04, PD-UASB-13) related to degrade toxic compounds. Therefore, it recommended the reactor mesophilic inoculum UASB (SGH) for the LAS degradation.

A fuzzy-logic-based model to predict biogas and methane production rates in a pilot-scale mesophilic UASB reactor treating molasses wastewater.

PubMed

Turkdogan-Aydinol, F Ilter; Yetilmezsoy, Kaan

2010-10-15

A MIMO (multiple inputs and multiple outputs) fuzzy-logic-based model was developed to predict biogas and methane production rates in a pilot-scale 90-L mesophilic up-flow anaerobic sludge blanket (UASB) reactor treating molasses wastewater. Five input variables such as volumetric organic loading rate (OLR), volumetric total chemical oxygen demand (TCOD) removal rate (R(V)), influent alkalinity, influent pH and effluent pH were fuzzified by the use of an artificial intelligence-based approach. Trapezoidal membership functions with eight levels were conducted for the fuzzy subsets, and a Mamdani-type fuzzy inference system was used to implement a total of 134 rules in the IF-THEN format. The product (prod) and the centre of gravity (COG, centroid) methods were employed as the inference operator and defuzzification methods, respectively. Fuzzy-logic predicted results were compared with the outputs of two exponential non-linear regression models derived in this study. The UASB reactor showed a remarkable performance on the treatment of molasses wastewater, with an average TCOD removal efficiency of 93 (+/-3)% and an average volumetric TCOD removal rate of 6.87 (+/-3.93) kg TCOD(removed)/m(3)-day, respectively. Findings of this study clearly indicated that, compared to non-linear regression models, the proposed MIMO fuzzy-logic-based model produced smaller deviations and exhibited a superior predictive performance on forecasting of both biogas and methane production rates with satisfactory determination coefficients over 0.98. 2010 Elsevier B.V. All rights reserved.

Biogas production from Jatropha curcas press-cake.

PubMed

Staubmann, R; Foidl, G; Foidl, N; Gübitz, G M; Lafferty, R M; Arbizu, V M; Steiner, W

1997-01-01

Seeds of the tropical plant Jatropha curcas (purge nut, physic nut) are used for the production of oil. Several methods for oil extraction have been developed. In all processes, about 50% of the weight of the seeds remain as a press cake containing mainly protein and carbohydrates. Investigations have shown that this residue contains toxic compounds and cannot be used as animal feed without further processing. Preliminary experiments have shown that the residue is a good substrate for biogas production. Biogas formation was studied using a semicontinous upflow anaerobic sludge blanket (UASB) reactor; a contact-process and an anaerobic filter each reactor having a total volume of 110 L. A maximum production rate of 3.5 m3 m"3 d"1 was obtained in the anaerobic filter with a loading rate of 13 kg COD m~3 d"1. However, the UASB reactor and the contact-process were not suitable for using this substrate. When using an anaerobic filter with Jatropha curcas seed cake as a substrate, 76% of the COD was degraded and 1 kg degraded COD yielded 355 L of biogas containing 70% methane.

Analysis of trichloroethylene removal and bacterial community function based on pH-adjusted in an upflow anaerobic sludge blanket reactor.

PubMed

Zhang, Ying; Hu, Miao; Li, Pengfei; Wang, Xin; Meng, Qingjuan

2015-11-01

The study reported the upflow anaerobic sludge blanket (UASB) reactor performance in treating wastewater containing trichloroethylene (TCE) and characterized variations of bacteria composition and structure by changing the pH from 6.0 to 8.0. A slightly acidic environment (pH < 7.0) had a greater impact on the TCE removal. Illumina pyrosequencing was applied to investigate the bacterial community changes in response to pH shifts. The results demonstrated that pH greatly influenced the dominance and presence of specific populations. The potential TCE degradation pathway in the UASB reactor was proposed. Importantly, the genus Dehalobacter which was capable of reductively dechlorinating TCE was detected, and it was not found at pH of 6.0, which presumably is the reason why the removal efficiency of TCE was the lowest (80.73 %). Through Pearson correlation analyses, the relative abundance of Dehalobacter positively correlated with TCE removal efficiency (R = 0.912). However, the relative abundance of Lactococcus negatively correlated with TCE removal efficiency according to the results from Pearson correlation analyses and redundancy analysis (RDA).

Continuous treatment of the insensitive munitions compound N-methyl-p-nitro aniline (MNA) in an upflow anaerobic sludge blanket (UASB) bioreactor.

PubMed

Olivares, Christopher I; Wang, Junqin; Luna, Carlos D Silva; Field, Jim A; Abrell, Leif; Sierra-Alvarez, Reyes

2016-02-01

N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized; however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d(-1). Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combining UASB technology and advanced oxidation processes (AOPs) to treat food processing wastewaters.

PubMed

Sigge, G O; Britz, J; Fourie, P C; Barnardt, C A; Strydom, R

2002-01-01

UASB treatment of fruit cannery and winery effluents was shown to be feasible. However, the treated effluents still have residual COD levels well above the legal limit of 75 mg.l(-1) for direct discharge to a water system and a form of post-treatment is necessary to reduce the COD further. Ozone and ozone/hydrogen peroxide were used in combination with a granular activated carbon contacting column to assess the effectiveness as a post-treatment option for the UASB treated fruit cannery and winery effluent. Colour reduction in the effluents ranged from 66 to 90% and COD reductions of 27-55% were achieved. The combination of ozone and hydrogen peroxide gave better results than ozonation alone. Significant progress was thus made in achieving the legal limit of 75 mg.l(-1).

Sulfide and ammonium oxidation, acetate mineralization by denitrification in a multipurpose UASB reactor.

PubMed

Beristain-Cardoso, Ricardo; Gómez, Jorge; Méndez-Pampín, Ramón

2011-02-01

The physiological and kinetic behavior of a denitrifying granular sludge exposed to different sulfide loading rates (55-295 mg/L d) were evaluated in a UASB reactor fed with acetate, ammonium and nitrate. At any sulfide loading rates, the consumption efficiencies of sulfide, acetate and ammonium were above 95%, while nitrate consumption efficiencies were around 62-72%. At the highest sulfide loading rate the ammonium was used as electron donor for N(2) production. The increase of sulfide loading rate also affected the fate of sulfide oxidation, since elemental sulfur was the main end product instead of sulfate. However, the lithotrophic denitrifying kinetic was not affected. FISH oligonucleotide probes for Thiobacillus denitrificans, Thiomiscropira denitrificans, genus Paracoccus and Pseudomonas spp. were used to follow the microbial ecology. The results of this work have shown that four pollutants could simultaneously be removed, namely, sulfide, ammonium, acetate and nitrate under well defined denitrifying conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Anaerobic treatment of municipal wastewater using the UASB-technology.

PubMed

Urban, I; Weichgrebe, D; Rosenwinkel, K-H

2007-01-01

The anaerobic treatment of municipal wastewater enables new applications for the reuse of wastewater. The effluent could be used for irrigation as the included nutrients are not affected by the treatment. Much more interesting now are renewable energies and the retrenchment of CO(2) emission. With the anaerobic treatment of municipal wastewater, not only can the CO(2) emission be reduced but "clean" energy supply can be gained by biogas. Most important for the sustainability of this process is the gathering of methane from the liquid effluent of the reactor, because the negative climate-relevant effect from the degassing methane is much higher than the positive effect from saving CO(2) emission. In this study, UASB reactors were used with a flocculent sludge blanket for the biodegradation of the carbon fraction in the wastewater with different temperatures and concentrations. It could be shown that the positive effect is much higher for municipal wastewater with high concentrations in hot climates.

Use of ozone and hydrogen peroxide in the post-treatment of UASB treated alkaline fruit cannery effluent.

PubMed

Sigge, G O; Britz, T J; Fouri, P C; Barnardt, C A; Strydom, R

2001-01-01

UASB treatment of cannery effluents was shown to be feasible. However, the treated effluent still does not allow direct discharge to a water system and a further form of post-treatment is necessary to reduce the COD to lower than the legal limit of 75 mg/l. The use of ozone, hydrogen peroxide and granular activated carbon were used singly or in combination to assess the effectiveness as post-treatment options for the UASB treated alkaline fruit cannery effluent. Colour reduction in the effluent ranged from 15% to 92% and COD reductions of 26-91% were achieved. Combinations of ozone and hydrogen peroxide gave better results than either oxidant singly. The best results were achieved by combining ozone, hydrogen peroxide and granular activated carbon, and COD levels were reduced to levels sufficiently below the 75 mg/l limit.

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

PubMed

Jordão, E P; Volschan, I

2004-01-01

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

Removal of High -Concentration and Refractory Organic Matter from Diosgenin Manufacture Wastewater : a case study of a demonstration project in Hubei Province, P R China

NASA Astrophysics Data System (ADS)

Bao, J.; Wang, L.

2009-12-01

Wastewater from diosgenin manufacture is dark brown (3,500 ~4,000 times of the chroma) and acidic(pH=0.8~1.5)with high concentration of organic matter(COD=25,000~38,000 mg/L)and poor biodegradability(BOD5/COD= 0.25~0.30). It is highly toxic to biota due to the water-soluble saponin, tannins and pectin. Therefore removal of the organic matter is of great importance before the discharge of the wastewater into the environment. Here we presented a set of data from a demonstration project in Hubei province, P R China with an improved technics. This technics, focusing on the treatment of diosgenin wastewater, included hydrolytic acidification, internal electrolysis, neutralization, aerating-improved Up-flow Anaerobic Sludge Bed (UASB) and bio-contact oxidation treatment in sequence to remove the organic matter. After 60 days of starting-up, the water quality from hydrolytic acidification reactor was greatly improved. The effluent became clear, indicating the obvious removal of suspended solids in the water; the ratio of BOD/COD increased to 0.44, suggesting an significant increase of biodegradability; the content of volatile fatty acid (VFA) increased from 22.6 mmol/L to 86.8 mmol/L and the volume loading of COD reached 9.48 kg COD/(m3d). Basically at this stage the removal efficiency of COD was stabilized at 25%. Further treatment was conducted on the effluent from hydrolytic acidification reactor through the Improved UASB Reactor after the internal electrolysis and neutralization. The Improved UASB Reactor can start up at room temperature with an influent of 1,500 mg/L COD and inflow rate of 50(m3/d). Then, temperature was increased gradually to 38 oC (± 2 oC) to optimize the growth of the mesophilic anaerobes in the reactor. The content of VFA of the effluent was controlled below 8 mmol/L to guarantee the pH in the range of 6.8~7.2. After 150 days of debugging, the COD of the influent to UASB increased to 9,600 mg/L, hydraulic retaining time (HRT) was around 70 hrs , the volume loading and the removal efficiency of COD reached 3.42 kg COD/(m3.d) and 75% respectively. Bio-contact oxidation process dealt with the effluent from the Improved UASB at room temperature. The HRT was 54 hrs and dissolved oxygen was controlled between 2 to 4 mg/L. Currently, the COD volume loading reached 1.05 kg COD/(m3.d) and the removal efficiency of COD was over 90%. The total removal efficiencies of COD and color were over 99% and 98% respectively in the overall process. The pH, color and COD content of the final effluent were 7, about 200 mg/L and 50 times of the chroma respectively. All these indexes met the criteria of “The National Discharge Standard of Industry Water Pollutants for Sapogenin”(GB 20425-2006). This work was supported by National Key Technologies R&D Program No. 2006BAB04A14-2), the Hubei Provincial Science and Technology Department (No. 2006AA305A05) and Wuhan Science and Technology Bureau (20066002101).

Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

PubMed

Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

2013-01-01

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

Impact of temperature on feed-flow characteristics and filtration performance of an upflow anaerobic sludge blanket coupled ultrafiltration membrane treating municipal wastewater.

PubMed

Ozgun, Hale; Tao, Yu; Ersahin, Mustafa Evren; Zhou, Zhongbo; Gimenez, Juan B; Spanjers, Henri; van Lier, Jules B

2015-10-15

The objective of this study was to assess the operational feasibility of an anaerobic membrane bioreactor (AnMBR), consisting of an upflow anaerobic sludge blanket (UASB) reactor coupled to an ultrafiltration membrane unit, at two operational temperatures (25°C and 15°C) for the treatment of municipal wastewater. The results showed that membrane fouling at 15°C was more severe than that at 25°C. Higher chemical oxygen demand (COD) and soluble microbial products (SMP) concentrations, lower mean particle diameter, and higher turbidity in the UASB effluent at lower temperature aggravated membrane fouling compared to the 25°C operation. However, the overall AnMBR treatment performance was not significantly affected by temperature, which was attributed to the physical membrane barrier. Cake resistance was found responsible for over 40% of the total fouling in both cases. However, an increase was observed in the contribution of pore blocking resistance at 15°C related to the larger amount of fine particles in the UASB effluent compared to 25°C. Based on the overall results, it is concluded that an AnMBR, consisting of a UASB coupled membrane unit, is not found technically feasible for the treatment of municipal wastewater at 15°C, considering the rapid deterioration of the filtration performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation and optimization of the novel UASB-MFC integrated system for sulfate removal and bioelectricity generation using the response surface methodology (RSM).

PubMed

Zhang, Baogang; Zhang, Jing; Yang, Qi; Feng, Chuanping; Zhu, Yuling; Ye, Zhengfang; Ni, Jinren

2012-11-01

COD/sulfate ratio and hydraulic residence time (HRT), both of which influence sulfate loadings jointly, are recognized as the most two important affecting factors for sulfate removal and bioelectricity generation in the novel up-flow anaerobic sludge blanket reactor-microbial fuel cell (UASB-MFC) integrated system. The response surface methodology (RSM) was employed for the optimization of this system and the optimum condition with COD/sulfate ratio of 2.3 and HRT of 54.3h was obtained with the target of maximizing the power output. In terms of maximizing the total sulfate removal efficiency, the obtained optimum condition was COD/sulfate ratio of 3.7 and HRT of 55.6h. Experimental results indicated the undistorted simulation and reliable optimized results. These demonstrated that RSM was effective to evaluate and optimize the UASB-MFC system for sulfate removal and energy recovery, providing a promising guide to further improvement of the system for potential applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation of soluble microbial products in a full-scale UASB reactor running at low organic loading rate.

PubMed

Zhou, Weili; Wu, Bingtao; She, Qianhong; Chi, Lina; Zhang, Zhenjia

2009-07-01

Investigation on a full-scale UASB treating industrial wastewater at a low organic loading rate (OLR) was conducted. Excellent treatment performance was achieved when treating the evaporator condensate of distillery wastewater at the OLR of less than 1 kg COD/m(3)d. Anaerobic effluent could be discharged without further treatment, which saved energy and running cost considerably. GC-MS analysis showed that the soluble microbial products (SMPs) were decreased to a low level at the low OLR. The main SMP in the anaerobic effluent were long chain carbohydrates and esters, accounting for 55-65% of the total organic matters. Anaerobic SMP was more complex than the aerobic ones. Soluble COD, protein and polysaccharide showed an obvious decrease at the sludge layer from 10 to 15m despite the low MLSS/MLVSS content. Methanogens were found to be predominant in this layer, which indicated that the methanogens might be the main consumers of the SMP in anaerobic reactors. Economic comparison confirmed that the anaerobic treatment at low OLR could be a good option.

INFLUENCE OF HYDRAULIC RETENTION TIME ON EXTENT OF PCE DECHLORINATION AND PRELIMINARY CHARACTERIZATION OF THE ENRICHMENT CULTURE. (R826694C703)

EPA Science Inventory

The extent of tetrachloroethene (PCE) dechlorination in two chemostats was evaluated as a function of hydraulic retention time (HRT). The inoculum of these chemostats was from an upflow anaerobic sludge blanket (UASB) reactor that rapidly converts PCE to vinyl chloride (VC) an...

Community onsite treatment of cold strong sewage in a UASB-septic tank.

PubMed

Al-Jamal, Wafa; Mahmoud, Nidal

2009-02-01

Two community onsite UASB-septic tanks namely R1 and R2 were operated under two different HRT (2 days for R1 and 4 days for R2) in parallel over a year and monitored over the cold half of the year. During the monitoring period, the sewage was characterised by a high COD(tot) of 905mg/l with a high fraction of COD(ss), viz. about 43.7%, and rather low temperature of 17.3 degrees C. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), COD(col), COD(dis), BOD(5) and TSS were "51%, 83%, 20%, 24%, 45% and 74%" and "54%, 87%, 10%, 28%, 49% and 78%", respectively. The difference in the removal efficiencies of those parameters in R1 and R2 is marginal and was only significant (p<0.05) for COD(sus). The sludge filling period of the reactors is expected to be 4-7 years. In view of that, the UASB-septic tank system is a robust and compact system as it can be adequately designed in Palestine at 2 days HRT.

Potential of resource recovery in UASB/trickling filter systems treating domestic sewage in developing countries.

PubMed

Bressani-Ribeiro, T; Brandt, E M F; Gutierrez, K G; Díaz, C A; Garcia, G B; Chernicharo, C A L

2017-04-01

This paper aims to present perspectives for energy (thermal and electric) and nutrient (N and S) recovery in domestic sewage treatment systems comprised of upflow anaerobic sludge blanket (UASB) reactors followed by sponge-bed trickling filters (SBTF) in developing countries. The resource recovery potential was characterized, taking into account 114 countries and a corresponding population of 968.9 million inhabitants living in the tropical world, which were grouped into three desired ranges in terms of cities' size. For each of these clusters, a technological arrangement flow-sheet was proposed, depending on their technical and economic viability from our best experience. Considering the population living in cities over 100, 000 inhabitants, the potential of energy and nutrient recovery via the sewage treatment scheme would be sufficient to generate electricity for approximately 3.2 million residents, as well as thermal energy for drying purposes that could result in a 24% volume reduction of sludge to be transported and disposed of in landfills. The results show that UASB/SBTF systems can play a very important role in the sanitation and environmental sector towards more sustainable sewage treatment plants.

High-rate two-phase process for the anaerobic degradation of cellulose, employing rumen microorganisms for an efficient acidogenesis

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

Gijzen, H.J.; Zwart, K.B.; Verhagen, F.J.M.

1988-04-05

A novel two-stage anaerobic process for the microbial conversion of cellulose into biogas has been developed. In the first phase, a mixed population of rumen bacteria and ciliates was used in the hydrolysis and fermentation of cellulose. The volatile fatty acids (VFA) produced in this acidogenic reactor were subsequently converted into biogas in a UASB-type methanogenic reactor. A stepwise increase of the loading rate from 11.9 to 25.8 g volatile solids/L reactor volume/day (g VS/L/day) did not affect the degradation efficiency in the acidogenic reactor, whereas the methanogenic reactor appeared to be overloaded at the highest loading rate. Cellulose digestionmore » was almost complete at all loading rates applied. The two-stage anaerobic process was also tested with a closed fluid circuit. In this instance total methane production was 0.438 L CH/sub 4//g VS added, which is equivalent to 98% of the theoretical value. The application of rumen microorganisms in combination with a high-rate methane reactor is proposed as a means of efficient anaerobic degradation of cellulosic residues to methane. Because this newly developed two-phase system is based on processes and microorganisms from the ruminant, it will be referred to as Rumen Derived Anaerobic Digestion (RUDAD)-process.« less

Effect of powdered activated carbon technology on short-cut nitrogen removal for coal gasification wastewater.

PubMed

Zhao, Qian; Han, Hongjun; Xu, Chunyan; Zhuang, Haifeng; Fang, Fang; Zhang, Linghan

2013-08-01

A combined process consisting of a powdered activated carbon technology (PACT) and short-cut biological nitrogen removal reactor (SBNR) was developed to enhance the removal efficiency of the total nitrogen (TN) from the effluent of an upflow anaerobic sludge bed (UASB) reactor, which was used to treat coal gasification wastewater (CGW). The SBNR performance was improved with the increasing of COD and TP removal efficiency via PACT. The average removal efficiencies of COD and TP in PACT were respectively 85.80% and 90.30%. Meanwhile, the NH3-N to NO2-N conversion rate was achieved 86.89% in SBNR and the total nitrogen (TN) removal efficiency was 75.54%. In contrast, the AOB in SBNR was significantly inhibited without PACT or with poor performance of PACT in advance, which rendered the removal of TN. Furthermore, PAC was demonstrated to remove some refractory compounds, which therefore improved the biodegradability of the coal gasification wastewater. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Sequential hydrogen and methane coproduction from sugary wastewater treatment by "CSTRHyd-UASBMet" system

NASA Astrophysics Data System (ADS)

Hao, Ping

2017-10-01

Potentiality of sequential hydrogen bioproduction from sugary wastewater treatment was investigated using continuous stirred tank reactor (CSTR) for various substrate COD concentrations and HRTs. At optimum substrate concentration of 6 g COD/L, hydrogen could be efficiently produced from CSTR with the highest production rate of 3.00 (±0.04) L/L reactor d at HRT of 6 h. The up flow anaerobic sludge bed (UASB) reactor was used for continuous methane bioproduction from the effluents of hydrogen bioproduction. At optimal HRT 12 h, methane could be produced with a production rate of 2.27 (±0.08) L/L reactor d and the COD removal efficiency reached up to the maximum 82.3%.

Fate of pharmaceuticals in full-scale source separated sanitation system.

PubMed

Butkovskyi, A; Hernandez Leal, L; Rijnaarts, H H M; Zeeman, G

2015-11-15

Removal of 14 pharmaceuticals and 3 of their transformation products was studied in a full-scale source separated sanitation system with separate collection and treatment of black water and grey water. Black water is treated in an up-flow anaerobic sludge blanket (UASB) reactor followed by oxygen-limited autotrophic nitrification-denitrification in a rotating biological contactor and struvite precipitation. Grey water is treated in an aerobic activated sludge process. Concentration of 10 pharmaceuticals and 2 transformation products in black water ranged between low μg/l to low mg/l. Additionally, 5 pharmaceuticals were also present in grey water in low μg/l range. Pharmaceutical influent loads were distributed over two streams, i.e. diclofenac was present for 70% in grey water, while the other compounds were predominantly associated to black water. Removal in the UASB reactor fed with black water exceeded 70% for 9 pharmaceuticals out of the 12 detected, with only two pharmaceuticals removed by sorption to sludge. Ibuprofen and the transformation product of naproxen, desmethylnaproxen, were removed in the rotating biological contactor. In contrast, only paracetamol removal exceeded 90% in the grey water treatment system while removal of other 7 pharmaceuticals was below 40% or even negative. The efficiency of pharmaceutical removal in the source separated sanitation system was compared with removal in the conventional sewage treatment plants. Furthermore, effluent concentrations of black water and grey water treatment systems were compared with predicted no-effect concentrations to assess toxicity of the effluent. Concentrations of diclofenac, ibuprofen and oxazepam in both effluents were higher than predicted no-effect concentrations, indicating the necessity of post-treatment. Ciprofloxacin, metoprolol and propranolol were found in UASB sludge in μg/g range, while pharmaceutical concentrations in struvite did not exceed the detection limits. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anaerobic treatment of coconut husk liquor for biogas production.

PubMed

Leitão, R C; Araújo, A M; Freitas-Neto, M A; Rosa, M F; Santaella, S T

2009-01-01

The market for coconut water causes environmental problems as it is one of the major agro-industrial solid wastes in some developing countries. With the aim of reusing the coconut husk, Embrapa developed a system for processing this raw material. During the dewatering stage Coconut Husk Liquor (CHL) is generated with chemical oxygen demand (COD) varying from 60 to 70 g/L due to high concentrations of sugars and tannins. The present study evaluated the feasibility of anaerobic treatment of CHL through Anaerobic Toxicity Assay and the operation of a lab-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. Results showed that CHL can be treated through a UASB reactor operating with an OLR that reaches up to 10 kg/m3.d and that is maintained stable during the whole operation. With this operational condition, the removal efficiency was higher than 80% for COD and approximately 78% for total tannins, and biogas production was 20 m3 of biogas or 130 KWh per m3 of CHL. Seventy-five percent of the biogas composition was methane and toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. Conversely, increasing the concentration of CHL leads to increased methanogenic activity.

Enhanced primary treatment of concentrated black water and kitchen residues within DESAR concept using two types of anaerobic digesters.

PubMed

Kujawa-Roeleveld, K; Elmitwalli, T; Zeeman, G

2006-01-01

Anaerobic digestion of concentrated domestic wastewater streams--black or brown water, and solid fraction of kitchen waste is considered as a core technology in a source separation based sanitation concept (DESAR--decentralised sanitation and reuse). A simple anaerobic digester can be implemented for an enhanced primary treatment or, in some situations, as a main treatment. Two reactor configurations were extensively studied; accumulation system (AC) and UASB septic tank at 15, 20 and 25 degrees C. Due to long retention times in an AC reactor, far stabilisation of treated medium can be accomplished with methanisation up to 60%. The AC systems are the most suitable to apply when the volume of waste to be treated is minimal and when a direct reuse of a treated medium in agriculture is possible. Digested effluent contains both liquid and solids. In a UASB septic tank, efficient separation of solids and liquid is accomplished. The total COD removal was above 80% at 25 degrees C. The effluent contains COD and nutrients, mainly in a soluble form. The frequency of excess sludge removal is low and sludge is well stabilised due to a long accumulation time.

Fluorescence-based monitoring of tracer and substrate distribution in an UASB reactor.

PubMed

Lou, S J; Tartakovsky, B; Zeng, Y; Wu, P; Guiot, S R

2006-11-01

In this work, rhodamine-related fluorescence was measured on-line at four reactor heights in order to study hydrodynamics within an upflow anaerobic sludge bed reactor. A linear dependence of the dispersion coefficient (D) on the upflow velocity was observed, while the influence of the organic loading rate (OLR) was insignificant. Furthermore, the Bodenstein number of the reactor loaded with granulated sludge was found to be position-dependent with the largest values measured at the bottom of the sludge bed. This trend was not observed in the reactor without sludge. Chemical oxygen demand (COD) and volatile fatty acid (VFA) concentrations were measured at the same reactor heights as in rhodamine tests using conventional off-line analytical methods and on-line multiwavelength fluorometry. Significant spatial COD and VFA gradients were observed at organic loading rates above 6g COD l(R)(-1)d(-1) and linear upflow velocities below 0.8m h(-1).

An Exploratory Study on the Pathways of Cr (VI) Reduction in Sulfate-reducing Up-flow Anaerobic Sludge Bed (UASB) Reactor

PubMed Central

Qian, Jin; Wei, Li; Liu, Rulong; Jiang, Feng; Hao, Xiaodi; Chen, Guang-Hao

2016-01-01

Electroplating wastewater contains both Cr (VI) and sulfate. So Cr (VI) removal under sulfate-rich condition is quite complicated. This study mainly investigates the pathways for Cr (VI) removal under biological sulfate-reducing condition in the up-flow anaerobic sludge bed (UASB) reactor. Two potential pathways are found for the removal of Cr (VI). The first one is the sulfidogenesis-induced Cr (VI) reduction pathway (for 90% Cr (VI) removal), in which Cr (VI) is reduced by sulfide generated from biological reduction of sulfate. The second one leads to direct reduction of Cr (VI) which is utilized by bacteria as the electron acceptor (for 10% Cr (VI) removal). Batch test results confirmed that sulfide was oxidized to elemental sulfur instead of sulfate during Cr (VI) reduction. The produced extracellular polymeric substances (EPS) provided protection to the microbes, resulting in effective removal of Cr (VI). Sulfate-reducing bacteria (SRB) genera accounted for 11.1% of the total bacterial community; thus they could be the major organisms mediating the sulfidogenesis-induced reduction of Cr (VI). In addition, chromate-utilizing genera (e.g. Microbacterium) were also detected, which were possibly responsible for the direct reduction of Cr (VI) using organics as the electron donor and Cr (VI) as the electron acceptor. PMID:27021522

Microalgal bacterial flocs treating paper mill effluent: A sunlight-based approach for removing carbon, nitrogen, phosphorus, and calcium.

PubMed

Van Den Hende, Sofie; Rodrigues, André; Hamaekers, Helen; Sonnenholzner, Stanislaus; Vervaeren, Han; Boon, Nico

2017-10-25

Treatment of upflow anaerobic sludge blanket (UASB) effluent from a paper mill in aerated activated sludge reactors involves high aeration costs. Moreover, this calcium-rich effluent leads to problematic scale formation. Therefore, a novel strategy for the aerobic treatment of paper mill UASB effluent in microalgal bacterial floc sequencing batch reactors (MaB-floc SBRs) is proposed, in which oxygen is provided via photosynthesis, and calcium is removed via bio-mineralization. Based on the results of batch experiments in the course of this study, a MaB-floc SBR was operated at an initial neutral pH. This SBR removed 58±21% organic carbon, 27±8% inorganic carbon, 77±5% nitrogen, 73±2% phosphorus, and 27±11% calcium. MaB-flocs contained 10±3% calcium, including biologically-influenced calcite crystals. The removal of calcium and inorganic carbon by MaB-flocs significantly decreased when inhibiting extracellular carbonic anhydrase (CA), an enzyme that catalyses the hydration and dehydration of CO 2 . This study demonstrates the potential of MaB-floc SBRs for the alternative treatment of calcium-rich paper mill effluent, and highlights the importance of extracellular CA in this treatment process. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

Santos, Priscila Ribeiro Dos; Daniel, Luiz Antonio

2017-05-01

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

Strategy to identify the causes and to solve a sludge granulation problem in methanogenic reactors: application to a full-scale plant treating cheese wastewater.

PubMed

Macarie, Hervé; Esquivel, Maricela; Laguna, Acela; Baron, Olivier; El Mamouni, Rachid; Guiot, Serge R; Monroy, Oscar

2017-08-26

Granulation of biomass is at the basis of the operation of the most successful anaerobic systems (UASB, EGSB and IC reactors) applied worldwide for wastewater treatment. Despite of decades of studies of the biomass granulation process, it is still not fully understood and controlled. "Degranulation/lack of granulation" is a problem that occurs sometimes in anaerobic systems resulting often in heavy loss of biomass and poor treatment efficiencies or even complete reactor failure. Such a problem occurred in Mexico in two full-scale UASB reactors treating cheese wastewater. A close follow-up of the plant was performed to try to identify the factors responsible for the phenomenon. Basically, the list of possible causes to a granulation problem that were investigated can be classified amongst nutritional, i.e. related to wastewater composition (e.g. deficiency or excess of macronutrients or micronutrients, too high COD proportion due to proteins or volatile fatty acids, high ammonium, sulphate or fat concentrations), operational (excessive loading rate, sub- or over-optimal water upflow velocity) and structural (poor hydraulic design of the plant). Despite of an intensive search, the causes of the granulation problems could not be identified. The present case remains however an example of the strategy that must be followed to identify these causes and could be used as a guide for plant operators or consultants who are confronted with a similar situation independently of the type of wastewater. According to a large literature based on successful experiments at lab scale, an attempt to artificially granulate the industrial reactor biomass through the dosage of a cationic polymer was also tested but equally failed. Instead of promoting granulation, the dosage caused a heavy sludge flotation. This shows that the scaling of such a procedure from lab to real scale cannot be advised right away unless its operability at such a scale can be demonstrated.

Polarized electrode enhances biological direct interspecies electron transfer for methane production in upflow anaerobic bioelectrochemical reactor.

PubMed

Feng, Qing; Song, Young-Chae; Yoo, Kyuseon; Kuppanan, Nanthakumar; Subudhi, Sanjukta; Lal, Banwari

2018-08-01

The influence of polarized electrodes on the methane production, which depends on the sludge concentration, was investigated in upflow anaerobic bioelectrochemical (UABE) reactor. When the polarized electrode was placed in the bottom zone with a high sludge concentration, the methane production was 5.34 L/L.d, which was 53% higher than upflow anaerobic sludge blanket (UASB) reactor. However, the methane production was reduced to 4.34 L/L.d by placing the electrode in the upper zone of the UABE reactor with lower sludge concentration. In the UABE reactor, the methane production was mainly improved by the enhanced biological direct interspecies electron transfer (bDIET) pathway, and the methane production via the electrode was a minor fraction of less than 4% of total methane production. The polarized electrodes that placed in the bottom zone with a high sludge concentration enhance the bDIET for methane production in the UABE reactor and greatly improve the methane production. Copyright © 2018. Published by Elsevier Ltd.

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

PubMed

Mungray, Arvind Kumar; Kumar, Pradeep

2008-05-01

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

Influence of nutrients on biomass evolution in an upflow anaerobic sludge blanket reactor degrading sulfate-laden organics.

PubMed

Patidar, S K; Tare, Vinod

2004-01-01

This paper describes the effect of the nutrients iron (Fe), nickel (Ni), zinc (Zn), cobalt (Co), and molybdenum (Mo) on biomass evolution in an upflow anaerobic sludge blanket (UASB) reactor metabolizing synthetic sulfate-laden organics at varying operating conditions during a period of 540 days. A bench-scale model of a UASB reactor was operated at a temperature of 35 degrees C for a chemical oxygen demand-to-sulfate (COD/SO4(2-)) ratio of 8.59 to 2.0, a sulfate loading rate of 0.54 to 1.88 kg SO4(2-)/m3 x d, and an organic loading rate of 1.9 to 5.75 kg COD/m3 x d. Biomass was characterized in terms of total methanogenic activity, acetate-utilizing methanogenic activity, total sulfidogenic activity, acetate-utilizing sulfidogenic activity, and scanning electron microscopy (SEM). Nickel and cobalt limitation appears to affect the activity of hydrogen-utilizing methane-producing bacteria (HMPB) significantly without having an appreciable effect on the activity of acetate-utilizing methane-producing bacteria (AMPB). Nickel and cobalt supplementation resulted in increased availability and, consequently, restoration of biomass activity and process performance. Iron limitation and sulfidogenic conditions resulted in the growth of low-density, hollow, fragile granules that washed out, causing process instability and performance deterioration. Iron and cobalt supplementation indicated significant stimulation of AMPB with slight inhibition of HMPB. Examination of biomass through SEM indicated a population shift with dominance of sarcina-type organisms and the formation of hollow granules. Granule disintegration was observed toward the end of the study.

A preliminary study on the occurrence and dissipation of estrogen in livestock wastewater.

PubMed

Tang, Xianjin; Naveedullah; Hashmi, Muhammad Zaffar; Zhang, Hu; Qian, Mingrong; Yu, Chunna; Shen, Chaofeng; Qin, Zhihui; Huang, Ronglang; Qiao, Jiani; Chen, Yingxu

2013-04-01

Livestock wastewater has high estrogen activity because animal excreta contain estrogen. In the past, when biological technologies were applied to treat livestock wastewater, the removal efficiency of estrogen pollutants was always ignored. Therefore, the efficiency of estrogen removal by anaerobic/aerobic (A/O) treatment and by up flow anaerobic sludge blanket and step-fed sequencing batch reactor (UASB-SFSBR) treatment was investigated in the present study. The results showed that the A/O treatment had no significant estrogenic removal ability, whereas the removal rates of estrogen after UASB-SFSBR treatment reached approximately 78 %, as measured by liquid chromatography and tandem mass spectrometry. The estrogen concentration decreased from 31.5 ng/L to an undetectable level according to the yeast estrogen screen analysis. We found differences between the estrogen removal rates measured by the chemical assay and those measured using the bioassay. More attention must be paid to the removal of estrogen pollutants in livestock wastewater to reduce the environmental risk.

Significance of dissolved methane in effluents of anaerobically treated low strength wastewater and potential for recovery as an energy product: A review.

PubMed

Crone, Brian C; Garland, Jay L; Sorial, George A; Vane, Leland M

2016-11-01

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10-30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11-100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Microporous membranes can recover up to 98.9% of dissolved methane in AnMBR effluents which have low COD and SS concentrations. Sequential Down-flow Hanging Sponge (DHS) reactors have been used to recover between 57 and 88% of dissolved methane from Upflow Anaerobic Sludge Blanket (UASB) reactor effluent at concentrations of greater than 30% and oxidize the rest for a 99% removal of total dissolved methane. They can also remove 90% of suspended solids and COD in UASB effluents and produce a high quality effluent. In situ degassing can increase process stability, COD removal, biomass retention, and headspace methane concentrations. A model for estimating energy consumption associated with membrane-based dissolved methane recovery predicts that recovered dissolved and headspace methane may provide all the energy required for operation of an anaerobic system treating DWW at psychrophilic temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Upflow anaerobic sludge blanket reactor--a review.

PubMed

Bal, A S; Dhagat, N N

2001-04-01

Biological treatment of wastewater basically reduces the pollutant concentration through microbial coagulation and removal of non-settleable organic colloidal solids. Organic matter is biologically stabilized so that no further oxygen demand is exerted by it. The biological treatment requires contact of the biomass with the substrate. Various advances and improvements in anaerobic reactors to achieve variations in contact time and method of contact have resulted in development of in suspended growth systems, attached growth or fixed film systems or combinations thereof. Although anaerobic systems for waste treatment have been used since late 19th century, they were considered to have limited treatment efficiencies and were too slow to serve the needs of a quickly expanding wastewater volume, especially in industrialized and densely populated areas. At present aerobic treatment is the most commonly used process to reduce the organic pollution level of both domestic and industrial wastewaters. Aerobic techniques, such as activated sludge process, trickling filters, oxidation ponds and aerated lagoons, with more or less intense mixing devices, have been successfully installed for domestic wastewater as well as industrial wastewater treatment. Anaerobic digestion systems have undergone modifications in the last two decades, mainly as a result of the energy crisis. Major developments have been made with regard to anaerobic metabolism, physiological interactions among different microbial species, effects of toxic compounds and biomass accumulation. Recent developments however, have demonstrated that anaerobic processes might be an economically attractive alternative for the treatment of different types of industrial wastewaters and in (semi-) tropical areas also for domestic wastewaters. The anaerobic degradation of complex, particulate organic matter has been described as a multistep process of series and parallel reactions. It involves the decomposition of organic and inorganic matter in the absence of molecular oxygen. Complex polymeric materials such as polysaccharides, proteins, and lipids (fat and grease) are first hydrolyzed to soluble products by extracellular enzymes, secreted by microorganisms, so as to facilitate their transport or diffusion across the cell membrane. These relatively simple, soluble compounds are fermented or anaerobically oxidized, further to short-chain fatty acids, alcohols, carbon dioxide, hydrogen, and ammonia. The short-chain fatty acids (other than acetate) are converted to acetate, hydrogen gas, and carbon dioxide. Methanogenesis finally occurs from the reduction of carbon dioxide and acetate by hydrogen. The initial stage of anaerobic degradation, i.e. acid fermentation is essentially a constant BOD stage because the organic molecules are only rearranged. The first stage does not stabilize the organics in the waste. However this step is essential for the initiation of second stage methane fermentation as it converts the organic material to a form, usable by the methane producing bacteria. The second reaction is initiated when anaerobic methane forming bacteria act upon the short chain organic acids produced in the 1st stage. Here these acids undergo methane fermentation with carbon dioxide acting as hydrogen acceptor and getting reduced to methane. The methane formed, being insoluble in water, escapes from the system and can be tapped and used as an energy source. The production and subsequent escape of methane causes the stabilization of the organic material. The methane-producing bacteria consist of several different groups. Each group has the ability to ferment only specific compounds. Therefore, the bacterial consortia in a methane producing system should include a number of different groups. When the rate of bacterial growth is considered, then the retention time of the solids becomes important parameter. The acid fermentation stage is faster as compared to the methane fermentation stage. This means that a sudden increase in the easily degradable organics will result in increased acid production with subsequent accumulation of acids. This inhibits the methanogenesis step. Acclimatization of the microorganisms to a substrate has been reported to take more than five weeks. Sufficiently acclimated bacteria have shown greater stability towards stress-inducing events such as hydraulic overloads, fluctuations in temperature, fluctuations in volatile acid and ammonia concentrations etc. Several environmental factors can affect anaerobic digestion, by altering the parameters such as specific growth rate, decay rate, gas production, substrate utilization, start-up and response to changes in input. It has long been recognized that an anaerobic process is in many ways ideal for wastewater treatment and has following merits: A high degree of waste stabilization A low production of excess A low nutrient requirements No oxygen requirement Production of methane gas Anaerobic microorganisms, especially methanogens have a slow growth rate. At lower HRTs, the possibility of washout of biomass is more prominent. This makes it difficult to maintain the effective number of useful microorganisms in the system. To maintain the population of anaerobes, large reactor volumes or higher HRTs are required. This may ultimately provide longer SRTs upto 20 days for high rate systems. Thus, provision of larger reactor volumes or higher HRTs ultimately lead to higher capital cost. Among notable disadvantages, it has low synthesis/reaction rate hence long start up periods and difficulty in recovery from upset conditions. Special attention is, therefore, warranted towards, controlling the factors that affect process adversely; important among them being environmental factors such as temperature, pH and concentration of toxic substances. The conventional anaerobic treatment process consists of a reactor containing waste and biological solids (bacteria) responsible for the digestion process. Concentrated waste (usually sewage sludge) can be added continuously or periodically (semi-batch operation), where it is mixed with the contents of the reactor. Theoretically, the conventional digester is operated as a once-through, completely mixed, reactor. In this particular mode of operation the hydraulic retention time (HRT) is equal to the solids retention time (SRT). Basically, the required process efficiency is related to the sludge retention time (SRT), and hence longer SRT provided, results in satisfactory population (by reproduction) for further waste stabilization. By reducing the hydraulic retention time (HRT) in the conventional mode reactor, the quantity of biological solids within the reactor is also decreased as the solids escape with the effluent. The limiting HRT is reached when the bacteria are removed from the reactor faster than they can grow. Methanogenic bacteria are slow growers and are considered the rate-limiting component in the anaerobic digestion process. The first anaerobic process developed, which separated the SRT from the HRT was the anaerobic contact process. In 1963, Young and McCarty (1968) began work, which eventually led to the development of the anaerobic upflow filter (AF) process. The anaerobic filter represented a significant advance in anaerobic waste treatment, since the filter can trap and maintain a high concentration of biological solids. By trapping these solids, long SRT's could be obtained at large waste flows, necessary to anaerobically treat low strength wastes at nominal temperatures economically. Another anaerobic process which relies on the development of biomass on the surfaces of a media is an expanded bed upflow reactor. The primary concept of the process consists of passing wastewater up through a bed of inert sand sized particles at sufficient velocities to fluidize and partially expand the sand bed. One of the more interesting new processes is the upflow anaerobic sludge blanket process (UASB), which was developed by Lettinga and his co-workers in Holland in the early 1970's. The key to the process was the discovery that anaerobic sludge inherently has superior flocculation and settling characteristics, provided the physical and chemical conditions for sludge flocculation are favorable. When these conditions are met, a high solids retention time (at high HRT loadings) can be achieved, with separation of the gas from the sludge solids. The UASB reactor is one of the reactor types with high loading capacity. It differs from other processes by the simplicity of its design. UASB process is a combination of physical & biological processes. The main feature of physical process is separation of solids and gases from the liquid and that of biological process is degradation of decomposable organic matter under anaerobic conditions. No separate settler with sludge return pump is required, as in the anaerobic contact process. There is no loss of reactor volume through filter or carrier material, as in the case with the anaerobic filter and fixed film reactor types, and there is no need for high rate effluent recirculation and concomitant pumping energy, as in the case with fluidized bed reactor. Anaerobic sludge inherently possesses good settling properties, provided the sludge is not exposed to heavy mechanical agitation. For this reason mechanical mixing is generally omitted in UASB-reactors. At high organic loading rates, the biogas production guarantees sufficient contact between substrate and biomass. Regarding the dynamic behaviour of the water phase UASB reactor approaches the completely mixed reactor. For achieving the required sufficient contact between sludge and wastewater, the UASB-system relies on the agitation brought about by the natural gas production and on an even feed inlet distribution at the bottom of the reactor. (ABSTRACT TRUNCATED)

[Effect of pilot UASB-SFSBR-MAP process for the large scale swine wastewater treatment].

PubMed

Wang, Liang; Chen, Chong-Jun; Chen, Ying-Xu; Wu, Wei-Xiang

2013-03-01

In this paper, a treatment process consisted of UASB, step-fed sequencing batch reactor (SFSBR) and magnesium ammonium phosphate precipitation reactor (MAP) was built to treat the large scale swine wastewater, which aimed at overcoming drawbacks of conventional anaerobic-aerobic treatment process and SBR treatment process, such as the low denitrification efficiency, high operating costs and high nutrient losses and so on. Based on the treatment process, a pilot engineering was constructed. It was concluded from the experiment results that the removal efficiency of COD, NH4(+) -N and TP reached 95.1%, 92.7% and 88.8%, the recovery rate of NH4(+) -N and TP by MAP process reached 23.9% and 83.8%, the effluent quality was superior to the discharge standard of pollutants for livestock and poultry breeding (GB 18596-2001), mass concentration of COD, TN, NH4(+) -N, TP and SS were not higher than 135, 116, 43, 7.3 and 50 mg x L(-1) respectively. The process developed was reliable, kept self-balance of carbon source and alkalinity, reached high nutrient recovery efficiency. And the operating cost was equal to that of the traditional anaerobic-aerobic treatment process. So the treatment process could provide a high value of application and dissemination and be fit for the treatment pf the large scale swine wastewater in China.

Stimulation of methanogenesis in anaerobic digesters treating leachate from a municipal solid waste incineration plant with carbon cloth.

PubMed

Lei, Yuqing; Sun, Dezhi; Dang, Yan; Chen, Huimin; Zhao, Zhiqiang; Zhang, Yaobin; Holmes, Dawn E

2016-12-01

Bio-methanogenic digestion of incineration leachate is hindered by high OLRs, which can lead to build-up of VFAs, drops in pH and ultimately in reactor souring. It was hypothesized that incorporation of carbon cloth into reactors treating leachate would promote DIET and enhance reactor performance. To examine this possibility, carbon cloth was added to laboratory-scale UASB reactors that were fed incineration leachate. As expected, the carbon-cloth amended reactor could operate stably with a 34.2% higher OLR than the control (49.4 vs 36.8kgCOD/(m 3 d)). Microbial community analysis showed that bacteria capable of extracellular electron transfer and methanogens known to participate in DIET were enriched on the carbon cloth surface, and conductivity of sludge from the carbon cloth amended reactor was almost twofold higher than sludge from the control (9.77 vs 5.47μS/cm), suggesting that microorganisms in the experimental reactor may have been expressing electrically conductive filaments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment and Energy Valorisation of an Agro-Industrial Effluent in Upflow Anaerobic Sludge Reactor (UASB)

NASA Astrophysics Data System (ADS)

Martins, Ramiro; Boaventura, Rui; Paulista, Larissa

2017-12-01

The accelerated growth of the population brings with it an increase in the generation of agro-industrial effluents. The inadequate discharge of these effluents significantly affects the quality of water resources. In this way, it becomes important to invest in treatment processes for agro-industrial effluents, particularly low-cost ones. In this context, the present study includes the design and construction of an UASB reactor and optimization of the anaerobic digestion treatment of the raw effluent from sweet chestnut production in the agro-industrial company Sortegel. The efficiency of the system was evaluated through the determination / monitoring of oxygen chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), biogas production rate and quality (% methane). The reactor was fed for 25 weeks and operated under mesophilic conditions (temperature 30-40 °C). Different values were tested for the hydraulic retention time (HRT) and volumetric flow rate (VF): 0.66 days (VF=1509 L.m-3.d-1); 1.33 days (VF=755 L.m-3.d-1); 2.41 d days (VF=415 L.m-3.d-1). The average COD removal efficiency reached values of 69%, 82% and 75%, respectively, and simultaneously the associated BOD5 removal efficiency was 84%, 91% and 70%. As regards TSS, removal values were 78%, 94% and 63%. In addition, high methane production rates were obtained, between 2500 and 4800 L CH4.kg-1 COD removed d-1. For all the hydraulic retention times tested, high concentrations of methane in the biogas were recorded: 66-75%, 70% and 75% for HRT of 0.66, 1.33 and 2.41 days, respectively.

Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste.

PubMed

Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

2014-02-01

Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodegradation of Methylene Blue Dye by Sequential Treatment Using Anaerobic Hybrid Reactor and Submerged Aerobic Fixed Film Bioreactor

NASA Astrophysics Data System (ADS)

Farooqi, Izharul H.; Basheer, Farrukh; Tiwari, Pradeepika

2017-12-01

Laboratory scale experiments were carried out to access the feasibility of sequential anaerobic/aerobic biological treatment for the biodegradation of Methylene Blue (MB) dye. Anaerobic studies were performed using anaerobic hybrid reactor (consisting of UASB and Anaerobic filter) whereas submerged aerobic fixed film reactor was used as aerobic reactor. Degradation of MB dye was attempted using neutralized acetic acid (1000 mg/L) as co-substrate. MB dye concentration was stepwise increased from 10 to 70 mg/L after reaching steady state in each dye concentration. Such a gradual increase in the dye concentration helps in the proper acclimatization of the sludge to dyes thereby avoiding the possible inhibitory effects to biological activities at high dye concentrations. The overall treatment efficiency of MB through sequential anaerobic-aerobic reactor operation was 90% at maximum attempted dye concentration of 70 mg/L. The effluent from anaerobic reactor was analysed for intermediate biodegradation products through HPLC. It was observed that catechol, quinone, amino pyrine, 1,4 diamino benzene were present. However they were absent in final effluent.

Upflow anaerobic sludge blanket and aerated constructed wetlands for swine wastewater treatment: a pilot study.

PubMed

Masi, F; Rizzo, A; Martinuzzi, N; Wallace, S D; Van Oirschot, D; Salazzari, P; Meers, E; Bresciani, R

2017-07-01

Swine wastewater management is often affected by two main issues: a too high volume for optimal reuse as a fertilizer and a too high strength for an economically sustainable treatment by classical solutions. Hence, an innovative scheme has been tested to treat swine wastewater, combining a low cost anaerobic reactor, upflow anaerobic sludge blanket (UASB), with intensified constructed wetlands (aerated CWs) in a pilot scale experimental study. The swine wastewater described in this paper is produced by a swine production facility situated in North Italy. The scheme of the pilot plant consisted of: (i) canvas-based thickener; (ii) UASB; (iii) two intensified aerated vertical subsurface flow CWs in series; (iv) a horizontal flow subsurface CW. The influent wastewater quality has been defined for total suspended solids (TSS 25,025 ± 9,323 mg/l), organic carbon (chemical oxygen demand (COD) 29,350 ± 16,983 mg/l), total reduced nitrogen and ammonium (total Kjeldahl nitrogen (TKN) 1,783 ± 498 mg/l and N-NH 4 + 735 ± 251 mg/l) and total phosphorus (1,285 ± 270 mg/l), with nitrates almost absent. The overall system has shown excellent performances in terms of TSS, COD, N-NH 4 + and TKN removal efficiencies (99.9%, 99.6%, 99.5%, and 99.0%, respectively). Denitrification (N-NO 3 - effluent concentration equal to 614 ± 268 mg/l) did not meet the Italian quality standards for discharging in water bodies, mainly because the organic carbon was almost completely removed in the intensified CW beds.

[Study on the start-up of anaerobic ammonium oxidation process in biological activated carbon reactor].

PubMed

Lai, Wei-Yi; Zhou, Wei-Li; He, Sheng-Bing

2013-08-01

In order to shorten the start-up time of anaerobic ammonium oxidation (ANAMMOX) reactor, biological activated cabon reactor was applied. Three lab scale UASB reactors were seeded with anaerobic sludge, fed with synthetic wastewater containing ammonia and nitrite, and supplemented with granular activated carbon on day 0, 33 and 56, respectively. The nitrogen removal performance of the first reactor, into which GAC was added on day 0, showed no significant improvement in 90 days. After being suspended for about one month, the secondary start-up of this reactor succeeded in another 33 days (totally 123 days). 49 d and 85 d were taken for the other two reactors started up by the addition of GAC on day 33 and 56, respectively. After the reactors were started up, the average removal rates of total nitrogen were 89.8%, 86.7% and 86.7%, respectively. The start-up process could be divided into four stages, namely, the bacterial autolysis phase, the lag phase, the improve phase and the stationary phase, and the best time for adding GAC carrier was right after the start of the lag phase.

Mass transfer dynamics of ammonia in high rate biomethanation of poultry litter leachate.

PubMed

Gangagni Rao, A; Gandu, Bharath; Swamy, Y V

2012-04-01

In the present study possibility of coupling biofilter to arrest ammonia (NH(3)) emission to the atmosphere from the integrated UASB and stripper (UASB+ST) system treating poultry litter leachate was studied. UASB+ST with biofilter (UASB+ST+BF) exhibited removal efficiency (RE) of NH(3) in the range of 98-99% (below 28 ppmV (parts per million by volume)) with low cost agricultural residue as a bedding material. Mass transfer dynamics of TAN in the system revealed that TAN loss to atmosphere was below 1% in UASB+ST+BF where as it was in the range of 70-90% in UASB+ST. Cost estimates revealed that financial implications due to the addition of biofilter were below 10% of total capital cost. TAN retained in the bedding material of biofilter could also be utilized as soil conditioner upon saturation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biohydrogen production and wastewater treatment from organic wastewater by anaerobic fermentation with UASB

NASA Astrophysics Data System (ADS)

Wang, Lu; Li, Yong-feng; Wang, Yi-xuan; Yang, Chuan-ping

2010-11-01

In order to discuss the ability of H2-production and wastewater treatment, an up-flow anaerobic sludge bed (UASB) using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the biomass of inoculants was 22.5 g SSṡL-1 and the influent concentration, hydraulic retention time (HRT) and initial pH were within the ranges of 4000˜6000 mg CODṡL-1, 8 h and 5-5.5, respectively, and the biohydrogen producing reactor could work effectively. The maximum hydrogen production rate is 5.98 Lṡd-1. Simultaneously, the concentration of ethanol and acetic acid is around 80% of the aqueous terminal production in the system, which presents the typical ethanol type fermentation. pH is at the range of 4˜4.5 during the whole performing process, however, the removal rate of COD is just about 20%. Therefore, it's still needs further research to successfully achieve the biohydrogen production and wastewater treatment, simultaneously.

Start-up of an UASB-septic tank for community on-site treatment of strong domestic sewage.

PubMed

Al-Shayah, Mohammad; Mahmoud, Nidal

2008-11-01

Two community on-site UASB-septic tanks were operated in parallel over a six months period under two different hydraulic retention times (HRT) of 2 days for R1 and 4 days for R2 at mean sewage temperature of 24 degrees C. The sewage was characterised by a high COD(tot) concentration of 1189 mg/L, with a large fraction of COD(sus), viz. 54%. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), BOD5 and TSS were "56%, 87%, 59% and 81%" and "58%, 90%, 60% and 82%" for both systems, respectively. R2 achieved a marginal but significant (p<0.05) better removal efficiencies of those parameters as compared to R1. The COD(col) and COD(dis) removals in R1 and R2 were respectively 31% and 20%, and 34% and 22%. The sludge accumulation was very low suggesting that the desludging frequency will be of several years. Accordingly, the reactor can be adequately designed at 2 days HRT.

The re-use of Waste-Activated Sludge as part of a "zero-sludge" strategy for wastewater treatments in the pulp and paper industry.

PubMed

Kaluža, Leon; Suštaršič, Matej; Rutar, Vera; Zupančič, Gregor D

2014-01-01

The possibility of introducing the thermo-alkali hydrolysis of Waste-Activated Sludge (WAS) was investigated, in order to enable the use of its solid residue as a raw material in cardboard production and the use of its liquid portion for anaerobic digestion in an UASB reactor. The evaluation of the hydrolysis at pH>12 and T=70°C showed that the microbe cells were disrupted with more than 90% efficiency in less than 2h. The solid portion was hygienised, therefore making it possible to integrate it into the cardboard production as a raw material for less demanding cardboards. Up to 6% addition of the liquid portion of hydrolysed WAS to wastewater decreased the specific biogas production in a pilot-scale UASB from 0.236 to 0.212 m(3)/kg(COD), while the efficiency of the COD removal decreased from 80.4% to 76.5%. These values still guarantee an adequate treatment of the wastewater and an increased biogas production by 16%. Copyright © 2013 Elsevier Ltd. All rights reserved.

Feedforward neural network model estimating pollutant removal process within mesophilic upflow anaerobic sludge blanket bioreactor treating industrial starch processing wastewater.

PubMed

Antwi, Philip; Li, Jianzheng; Meng, Jia; Deng, Kaiwen; Koblah Quashie, Frank; Li, Jiuling; Opoku Boadi, Portia

2018-06-01

In this a, three-layered feedforward-backpropagation artificial neural network (BPANN) model was developed and employed to evaluate COD removal an upflow anaerobic sludge blanket (UASB) reactor treating industrial starch processing wastewater. At the end of UASB operation, microbial community characterization revealed satisfactory composition of microbes whereas morphology depicted rod-shaped archaea. pH, COD, NH 4 + , VFA, OLR and biogas yield were selected by principal component analysis and used as input variables. Whilst tangent sigmoid function (tansig) and linear function (purelin) were assigned as activation functions at the hidden-layer and output-layer, respectively, optimum BPANN architecture was achieved with Levenberg-Marquardt algorithm (trainlm) after eleven training algorithms had been tested. Based on performance indicators such the mean squared errors, fractional variance, index of agreement and coefficient of determination (R 2 ), the BPANN model demonstrated significant performance with R 2 reaching 87%. The study revealed that, control and optimization of an anaerobic digestion process with BPANN model was feasible. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimation of biogas and methane yields in an UASB treating potato starch processing wastewater with backpropagation artificial neural network.

PubMed

Antwi, Philip; Li, Jianzheng; Boadi, Portia Opoku; Meng, Jia; Shi, En; Deng, Kaiwen; Bondinuba, Francis Kwesi

2017-03-01

Three-layered feedforward backpropagation (BP) artificial neural networks (ANN) and multiple nonlinear regression (MnLR) models were developed to estimate biogas and methane yield in an upflow anaerobic sludge blanket (UASB) reactor treating potato starch processing wastewater (PSPW). Anaerobic process parameters were optimized to identify their importance on methanation. pH, total chemical oxygen demand, ammonium, alkalinity, total Kjeldahl nitrogen, total phosphorus, volatile fatty acids and hydraulic retention time selected based on principal component analysis were used as input variables, whiles biogas and methane yield were employed as target variables. Quasi-Newton method and conjugate gradient backpropagation algorithms were best among eleven training algorithms. Coefficient of determination (R 2 ) of the BP-ANN reached 98.72% and 97.93% whiles MnLR model attained 93.9% and 91.08% for biogas and methane yield, respectively. Compared with the MnLR model, BP-ANN model demonstrated significant performance, suggesting possible control of the anaerobic digestion process with the BP-ANN model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of wastewater containing a large amount of suspended solids by a novel multi-staged UASB reactor.

PubMed

Uemura, S; Harada, H; Ohashi, A; Torimura, S

2005-12-01

Treatment of artificial wastewater containing a large amount of suspended solids comprised of soybean processing waste and pig fodder was studied using a novel multi-staged upflow anaerobic sludge blanket reactor. The reactor consisted of three compartments, each containing a gas solid separator. The wastewater had chemical oxygen demand of approximately 21600 mg l(-1), suspended solids of 12800 mg l(-1), and an ammonia concentration of 945 mg l(-1). A continuous experiment without effluent circulation showed that the multi-staged reactor was not that effective for the treatment of wastewater containing a large amount of suspended solids. However, operation of the reactor with circulation of effluent enabled the reactor to achieve organic removal of 85% and approximately 70% methane conversion at loading rates of between 4.0 to 5.4 kg-chemical oxygen demand per cubic meter per day, meaning that the reactor was more effective when effluent was circulated. Morphological investigation revealed that the crude fiber in the sludge was partially degraded and that it had many small depressions on its surface. Evolved biogas may have become caught in these depressions of the fibers and caused washout of the sludge.

Kinetics of anaerobic treatment of landfill leachates combined with urban wastewaters.

PubMed

Fueyo, Gema; Gutiérrez, Antonio; Berrueta, José

2003-04-01

The anaerobic degradation of landfill leachates mixed with domestic wastewater has been studied in a pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. A previous work in laboratory-scale had shown that a fraction (5%) of the refractory organic matter could be additionally degraded when these two substrates were treated in conjunction, but this synergistic effect in the Chemical Oxygen Demand (COD) removal was not reproduced. However, the mass loading rate for which the maximum degradation was obtained was higher for the mixtures (0.5 kg COD/kg SSV x d) than for the separated components (0.18 and 0.19), allowing an increase in the treatment capacity of the leachates. The methane productivity (304 L/kg COD) was close to the theoretical maximum and independent of the proportion of the mixture components. The experimental data were fitted to a modification of Haldane's kinetic model, in which the parameters depend on the hydraulic residence time and the biomass concentration.

Biofilm formation and granule properties in anaerobic digestion at high salinity.

PubMed

Gagliano, M C; Ismail, S B; Stams, A J M; Plugge, C M; Temmink, H; Van Lier, J B

2017-09-15

For the anaerobic biological treatment of saline wastewater, Anaerobic Digestion (AD) is currently a possibility, even though elevated salt concentrations can be a major obstacle. Anaerobic consortia and especially methanogenic archaea are very sensitive to fluctuations in salinity. When working with Upflow Sludge Blanket Reactor (UASB) technology, in which the microorganisms are aggregated and retained in the system as a granular biofilm, high sodium concentration negatively affects aggregation and consequently process performances. In this research, we analysed the structure of the biofilm and granules formed during the anaerobic treatment of high salinity (at 10 and 20 g/L of sodium) synthetic wastewater at lab scale. The acclimated inoculum was able to accomplish high rates of organics removal at all the salinity levels tested. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses identified the acetoclastic Methanosaeta harundinacea as the key player involved acetate degradation and microbial attachment/granulation. When additional calcium (1 g/L) was added to overcome the negative effect of sodium on microbial aggregation, during the biofilm formation process microbial attachment and acetate degradation decreased. The same result was observed on granules formation: while calcium had a positive effect on granules strength when added to UASB reactors, Methanosaeta filaments were not present and the degradation of the partially acidified substrate was negatively influenced. This research demonstrated the possibility to get granulation at high salinity, bringing to the forefront the importance of a selection towards Methanosaeta cells growing in filamentous form to obtain strong and healthy granules. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Clostridium thiosulfatireducens sp. nov., a proteolytic, thiosulfate- and sulfur-reducing bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Hernández-Eugenio, Guadalupe; Fardeau, Marie-Laure; Cayol, Jean-Luc; Patel, Bharat K C; Thomas, Pierre; Macarie, Hervé; Garcia, Jean-Louis; Ollivier, Bernard

2002-09-01

A strictly anaerobic, gram-positive, sporulating rod (0.5-0.6 x 2.0-4.0 microm), designated strain Lup 21T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating cheese-factory wastewater. Strain Lup 21T was motile by means of peritrichous flagella, had a G+C content of 31.4 mol% and grew optimally at 37 degrees C, pH 7.4, in the absence of NaCl. It is a heterotrophic micro-organism, utilizing proteinaceous compounds (gelatin, peptides, Casamino acids and various single amino acids) but unable to use any of the carbohydrates tested as a carbon and energy source. It reduced thiosulfate and elemental sulfur to sulfide in the presence of Casamino acids as carbon and energy sources. Acetate, butyrate, isobutyrate, isovalerate, CO2 and sulfide were end products from oxidation of gelatin and Casamino acids in the presence of thiosulfate as an electron acceptor. In the absence of thiosulfate, serine, lysine, methionine and histidine were fermented. On the basis of 16S rRNA similarity, strain Lup 21T was related to members of the low-G+C Clostridiales group, Clostridium subterminale DSM 6970T being the closest relative (with a sequence similarity of 99.4%). DNA-DNA hybridization was 56% with this species. On the basis of phenotypic, genotypic and phylogenetic characteristics, the isolate was designated as a novel species of the genus Clostridium, Clostridium thiosulfatireducens sp. nov. The type strain is strain Lup 21T (= DSM 13105T = CIP 106908T).

Optimization of food waste hydrolysis in leach bed coupled with methanogenic reactor: effect of pH and bulking agent.

PubMed

Xu, Su Yun; Lam, Hoi Pui; Karthikeyan, O Parthiba; Wong, Jonathan W C

2011-02-01

The effects of pH and bulking agents on hydrolysis/acidogenesis of food waste were studied using leach bed reactor (LBR) coupled with methanogenic up-flow anaerobic sludge blanket (UASB) reactor. The hydrolysis rate under regulated pH (6.0) was studied and compared with unregulated one during initial experiment. Then, the efficacies of five different bulking agents, i.e. plastic full particles, plastic hollow sphere, bottom ash, wood chip and saw dust were experimented under the regulated pH condition. Leachate recirculation with 50% water replacement was practiced throughout the experiment. Results proved that the daily leachate recirculation with pH control (6.0) accelerated the hydrolysis rate (59% higher volatile fatty acids) and methane production (up to 88%) compared to that of control without pH control. Furthermore, bottom ash improved the reactor alkalinity, which internally buffered the system that improved the methane production rate (0.182 l CH(4)/g VS(added)) than other bulking agents. Copyright © 2010 Elsevier Ltd. All rights reserved.

Long-term performance of high-rate anaerobic reactors for the treatment of oily wastewater.

PubMed

Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2006-10-15

Complex oily wastewater from a food industry was treated in three different UASB reactors at different operating conditions. Although all three systems achieved fat, oil, and grease (FOG) and COD removal efficiencies above 80% at an organic loading of 3 kg COD/m3 x d, system performance deteriorated sharply at higher loading rates, and the presence of high FOG caused a severe sludge flotation resulting in failure. Initially, FOG accumulated onto the biomass which led to sludge flotation and washout of biomass. The loss of sludge in the bed increased the FOG loading to the biomass and failure ensued. Contrary to previous findings, accumulation of FOG rather than influent FOG concentrations or volumetric FOG loading rate was the most importantfactor governing the high-rate anaerobic reactor performance. The critical accumulated FOG loading was identified as 1.04 +/- 0.13 g FOG/g VSS for all three reactors. Furthermore, FOG accumulation onto the biomass was identified mainly as palmitic acid (>60%) whereas the feed LCFA contained only 30% of palmitic acid and 50% of oleic acid.

Microbial granulation for lactic acid production.

PubMed

Kim, Dong-Hoon; Lee, Mo-Kwon; Hwang, Yuhoon; Im, Wan-Taek; Yun, Yeo-Myeong; Park, Chul; Kim, Mi-Sun

2016-01-01

This work investigated the formation of microbial granules to boost the productivity of lactic acid (LA). The flocculated form of LA-producing microbial consortium, dominated by Lactobacillus sp. (91.5% of total sequence), was initially obtained in a continuous stirred-tank reactor (CSTR), which was fed with 2% glucose and operated at a hydraulic retention time (HRT) of 12 h and pH 5.0 ± 0.1 under a thermophilic condition (50°C). The mixed liquor in the CSTR was then transferred to an up-flow anaerobic sludge blanket reactor (UASB). The fermentation performance and granulation process were monitored with a gradual decrease of HRT from 8.0 to 0.17 h, corresponding to an increase in the substrate loading from 60 to 2,880 g glucose L(-1) d(-1) . As the operation continued, the accumulation of biomass in the UASB was clearly observed, which changed from flocculent to granular form with decrease in HRT. Up to the HRT decrease to 0.5 h, the LA concentration was maintained at 19-20 g L(-1) with over 90% of substrate removal efficiency. However, further decrease of HRT resulted in a decrease of LA concentration with increase in residual glucose. Nevertheless, the volumetric LA productivity continuously increased, reaching 67 g L-fermenter (-1) h(-1) at HRT 0.17 h. The size of LA-producing granules and hydrophobicity gradually increased with decrease in HRT, reaching 6.0 mm and 60%, respectively. These biogranules were also found to have high settling velocities and low porosities, ranging 2.69-4.73 cm s(-1) and 0.39-0.92, respectively. © 2015 Wiley Periodicals, Inc.

Influence of preservation temperature on the characteristics of anaerobic ammonium oxidation (anammox) granular sludge.

PubMed

Xing, Bao-Shan; Guo, Qiong; Jiang, Xiao-Yan; Chen, Qian-Qian; Li, Peng; Ni, Wei-Min; Jin, Ren-Cun

2016-05-01

Preserving active anaerobic ammonium oxidation (anammox) biomass is a potential method for securing sufficient seeding biomass for the rapid start-up of full-scale anammox processes. In this study, anammox granules were cultured in an upflow anaerobic sludge blanket (UASB) reactor (R0), and then the enriched anammox granules were preserved at 35, 20, 4, and -30 °C. The subsequent reactivation characteristics of the granules were evaluated in four UASB reactors (denoted R1, R2, R3, and R4, respectively) to investigate the effect of preservation temperature on the characteristics of anammox granules and their reactivation performance. The results demonstrated that 4 °C was the optimal preservation temperature for maintaining the biomass, activity, settleability, and integrity of the anammox granules and their cellular structures. During the preservation period, a first-order exponential decay model may be used to simulate the decay of anammox biomass and activity. The protein-to-polysaccharide ratio in the extracellular polymeric substances and the heme c content could not effectively indicate the changes in settleability and activity of the anammox granules, respectively, and a loss of bioactivity was positively associated with the degree of anaerobic ammonium-oxidizing bacteria cell lysis. After 42 days of storage, the anammox granules preserved at 4 °C (R3) exhibited a better recovery performance than those preserved at 20 °C (R2), -30 °C (R4), and 35 °C (R1). The comprehensive comparison indicated that 4 °C is the optimal storage temperature for anammox granular sludge because it promotes improved maintenance and recovery performance properties.

Microbial dynamics in upflow anaerobic sludge blanket (UASB) bioreactor granules in response to short-term changes in substrate feed

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

Kovacik, William P.; Scholten, Johannes C.; Culley, David E.

2010-08-01

The complexity and diversity of the microbial communities in biogranules from an upflow anaerobic sludge blanket (UASB) bioreactor were determined in response to short-term changes in substrate feeds. The reactor was fed simulated brewery wastewater (SBWW) (70% ethanol, 15% acetate, 15% propionate) for 1.5 months (phase 1), acetate / sulfate for 2 months (phase 2), acetate-alone for 3 months (phase 3), and then a return to SBWW for 2 months (phase 4). Performance of the reactor remained relatively stable throughout the experiment as shown by COD removal and gas production. 16S rDNA, methanogen-associated mcrA and sulfate reducer-associated dsrAB genes weremore » PCR amplified, then cloned and sequenced. Sequence analysis of 16S clone libraries showed a relatively simple community composed mainly of the methanogenic Archaea (Methanobacterium and Methanosaeta), members of the Green Non-Sulfur (Chloroflexi) group of Bacteria, followed by fewer numbers of Syntrophobacter, Spirochaeta, Acidobacteria and Cytophaga-related Bacterial sequences. Methanogen-related mcrA clone libraries were dominated throughout by Methanobacter and Methanospirillum related sequences. Although not numerous enough to be detected in our 16S rDNA libraries, sulfate reducers were detected in dsrAB clone libraries, with sequences related to Desulfovibrio and Desulfomonile. Community diversity levels (Shannon-Weiner index) generally decreased for all libraries in response to a change from SBWW to acetate-alone feed. But there was a large transitory increase noted in 16S diversity at the two-month sampling on acetate-alone, entirely related to an increase in Bacterial diversity. Upon return to SBWW conditions in phase 4, all diversity measures returned to near phase 1 levels.« less

Performance and model of a full-scale up-flow anaerobic sludge blanket (UASB) to treat the pharmaceutical wastewater containing 6-APA and amoxicillin.

PubMed

Chen, Zhiqiang; Wang, Hongcheng; Chen, Zhaobo; Ren, Nanqi; Wang, Aijie; Shi, Yue; Li, Xiaoming

2011-01-30

A full-scale test was conducted with an up-flow anaerobic sludge blanket (UASB) pre-treating pharmaceutical wastewater containing 6-aminopenicillanic acid (6-APA) and amoxicillin. The aim of the study is to investigate the performance of UASB in the condition of a high chemical oxygen demand (COD) loading rate from 12.57 to 21.02 kgm(-3)d(-1) and a wide pH from 5.57 to 8.26, in order to provide a reference for treating the similar chemical synthetic pharmaceutical wastewater containing 6-APA and amoxicillin. The results demonstrated that the UASB average percentage reduction in COD, 6-APA and amoxicillin were 52.2%, 26.3% and 21.6%, respectively. In addition, three models, built on the back propagation neural network (BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the biodegradation of pharmaceutical wastewater containing 6-APA and amoxicillin. The average error of COD, 6-APA and amoxicillin were -0.63%, 2.19% and 5.40%, respectively. The results indicated that these models built on the BPNN theory were well-fitted to the detected data, and were able to simulate and predict the removal of COD, 6-APA and amoxicillin by UASB. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Recent insights into the cell immobilization technology applied for dark fermentative hydrogen production.

PubMed

Kumar, Gopalakrishnan; Mudhoo, Ackmez; Sivagurunathan, Periyasamy; Nagarajan, Dillirani; Ghimire, Anish; Lay, Chyi-How; Lin, Chiu-Yue; Lee, Duu-Jong; Chang, Jo-Shu

2016-11-01

The contribution and insights of the immobilization technology in the recent years with regards to the generation of (bio)hydrogen via dark fermentation have been reviewed. The types of immobilization practices, such as entrapment, encapsulation and adsorption, are discussed. Materials and carriers used for cell immobilization are also comprehensively surveyed. New development of nano-based immobilization and nano-materials has been highlighted pertaining to the specific subject of this review. The microorganisms and the type of carbon sources applied in the dark hydrogen fermentation are also discussed and summarized. In addition, the essential components of process operation and reactor configuration using immobilized microbial cultures in the design of varieties of bioreactors (such as fixed bed reactor, CSTR and UASB) are spotlighted. Finally, suggestions and future directions of this field are provided to assist the development of efficient, economical and sustainable hydrogen production technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems.

PubMed

Luostarinen, Sari; Sanders, Wendy; Kujawa-Roeleveld, Katarzyna; Zeeman, Grietje

2007-03-01

The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of COD(dis) was at first negative, but improved as the sludge adapted to low temperature. The UASB-septic tank alone did not comply with Finnish or Dutch treatment requirements and should therefore be considered mainly as a pre-treatment method. However, measuring the requirements as mgCOD l(-1) may not always be the best method, as the volume of the effluent discharged is also an important factor in the final amount of COD entering the receiving water bodies.

Microbial aggregates in anaerobic wastewater treatment.

PubMed

Kosaric, N; Blaszczyk, R

1990-01-01

The phenomenon aggregation of anaerobic bacteria gives an opportunity to speed up the digestion rate during methanogenesis. The aggregates are mainly composed of methanogenic bacteria which convert acetate and H2/CO2 into methane. Other bacteria are also included in the aggregates but their concentration is rather small. The aggregates may also be formed during acetogenesis or even hydrolysis but such aggregates are not stable and disrupt quickly when not fed. A two stage process seems to be suitable when high concentrated solid waste must be treated. Special conditions are necessary to promote aggregate formation from methanogenic bacteria but aggregates once formed are stable without feeding even for a few years. The structure, texture and activity of bacterial aggregates depend on several parameters: (1)--temperature and pH, (2)--wastewater composition and (3)--hydrodynamic conditions within the reactor. The common influence of all these parameters is still rather unknown but some recommendations may be given. Temperature and pH should be maintained in the range which is optimal for methanogenic bacteria e.g. a temperature between 32 and 50 degrees C and a value pH between 6.5 and 7.5. Wastewaters should contain soluble wastes and the specific loading rate should be around one kgCOD(kgVSS)-1 d-1. The concentration of the elements influences aggregate composition and probably structure and texture. At high calcium concentration a change in the colour of the granules has been observed. Research is necessary to investigate the influence of other elements and organic toxicants on maintenance of the aggregates. Hydrodynamic conditions seem to influence the stability of the granules over long time periods. At low liquid stream rates, aggregates may starve and lysis within the aggregates is possible which results in hollowing of aggregates and their floating. At high liquid stream rates the aggregates may be disrupted and washed out of the reactor as a flocculent sludge. Methanogenic bacterial aggregates have been successfully applied in many full scale installations, especially for sugar beet, potato, pulp and paper mill, and other soluble wastes. The UASB reactors used for these treatments are simple in construction and handling which result in rather low total costs. A further and wider application of UASB reactors and methanogenic aggregates for various industrial wastewaters is expected.

Anaerobic/aerobic treatment of greywater via UASB and MBR for unrestricted reuse.

PubMed

Abdel-Shafy, Hussein I; Al-Sulaiman, Ahmed Makki; Mansour, Mona S M

2015-01-01

The aim of the present study was to investigate the efficiency of integrated up-flow anaerobic sludge blanket (UASB) as anaerobic system followed by membrane bioreactor (MBR) as aerobic system for the treatment of greywater for unrestricted reuse. Pilot-scale UASB and MBR units were installed and operated in the NRC, Egypt. Real raw greywater was subjected to UASB and the effluent was further treated with microfiltration MBR. The necessary trans-membrane pressure difference is applied by the water head above the membrane (gravity flow) without any energy input. The average characteristics of the raw greywater were 95, 392, 298, 10.45, 0.4, 118.5 and 28 mg/L for total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphates, nitrates, oil and grease, and total Kjeldahl nitrogen (TKN), respectively. The pH was 6.71. The UASB treatment efficiency reached 19.3, 57.8, 67.5 and 83.7% for TSS, COD, BOD5 and oil and grease, respectively. When the UASB effluent was further treated with MBR, the overall removal rate achieved 97.7, 97.8, 97.4 and 95.8% for the same parameters successively. The characteristics of the final effluent reached 2.5, 8.5, 6.1, 0.95, 4.6 and 2.3 mg/L for TSS, COD, BOD, phosphates, oil and grease and TKN, respectively. This final treated effluent could cope with the unrestricted water reuse of local Egyptian guidelines.

Effect of organic matter strength on anammox for modified greenhouse turtle breeding wastewater treatment.

PubMed

Chen, Chongjun; Huang, Xiaoxiao; Lei, Chenxiao; Zhang, Tian C; Wu, Weixiang

2013-11-01

Anaerobic ammonium-N removal from modified greenhouse turtle breeding wastewater with different chemical oxygen demand (COD) strengths (194.0-577.8 mg L(-1)) at relatively fixed C/N ratios (≈ 2) was investigated using a lab-scale up-flow anaerobic sludge blanket (UASB) anammox reactor. During the entire experiment, the total nitrogen (TN) removal efficiency was about 85% or higher, while the average COD removal efficiency was around 56.5 ± 7.9%. Based on the nitrogen and carbon balance, the nitrogen removal contribution was 79.6 ± 4.2% for anammox, 12.7 ± 3.0% for denitrification+denitritation and 7.7 ± 4.9% for other mechanisms. Denaturing gradient gel electrophoresis (DGGE) analyses revealed that Planctomycete, Proteobacteria and Chloroflexi bacteria were coexisted in the reactor. Anammox was always dominant when the reactor was fed with different COD concentrations, which indicated the stability of the anammox process with the coexistence of the denitrification process in treating greenhouse turtle breeding wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of carbon source and inoculum type on anaerobic biomass adhesion on polyurethane foam in reactors fed with acid mine drainage.

PubMed

Rodriguez, Renata P; Zaiat, Marcelo

2011-04-01

This paper analyzes the influence of carbon source and inoculum origin on the dynamics of biomass adhesion to an inert support in anaerobic reactors fed with acid mine drainage. Formic acid, lactic acid and ethanol were used as carbon sources. Two different inocula were evaluated: one taken from an UASB reactor and other from the sediment of a uranium mine. The values of average colonization rates and the maximum biomass concentration (C(max)) were inversely proportional to the number of carbon atoms in each substrate. The highest C(max) value (0.35 g TVS g(-1) foam) was observed with formic acid and anaerobic sludge as inoculum. Maximum colonization rates (v(max)) were strongly influenced by the type of inoculum when ethanol and lactic acid were used. For both carbon sources, the use of mine sediment as inoculum resulted in a v(max) of 0.013 g TVS g(-1) foam day(-1), whereas 0.024 g TVS g(-1) foam day(-1) was achieved with anaerobic sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

In-situ biogas upgrading in thermophilic granular UASB reactor: key factors affecting the hydrogen mass transfer rate.

PubMed

Bassani, Ilaria; Kougias, Panagiotis G; Angelidaki, Irini

2016-12-01

Biological biogas upgrading coupling CO 2 with external H 2 to form biomethane opens new avenues for sustainable biofuel production. For developing this technology, efficient H 2 to liquid transfer is fundamental. This study proposes an innovative setup for in-situ biogas upgrading converting the CO 2 in the biogas into CH 4 , via hydrogenotrophic methanogenesis. The setup consisted of a granular reactor connected to a separate chamber, where H 2 was injected. Different packing materials (rashig rings and alumina ceramic sponge) were tested to increase gas-liquid mass transfer. This aspect was optimized by liquid and gas recirculation and chamber configuration. It was shown that by distributing H 2 through a metallic diffuser followed by ceramic sponge in a separate chamber, having a volume of 25% of the reactor, and by applying a mild gas recirculation, CO 2 content in the biogas dropped from 42 to 10% and the final biogas was upgraded from 58 to 82% CH 4 content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combining sun-based technologies (microalgae and solar disinfection) for urban wastewater regeneration.

PubMed

Gutiérrez-Alfaro, Sergio; Rueda-Márquez, Juan J; Perales, José A; Manzano, Manuel A

2018-04-01

Solar disinfection (SODIS) of urban wastewater can be a suitable technology for improving the microbiological quality of reclaimed water as a complement to other extensive and environmentally friendly technologies such as microalgae biotreatment. The objective of this work is to evaluate the feasibility of incorporating the SODIS technology at the end of a pilot scale urban wastewater treatment plant (WWTP) where the processes are based on microalgae biotechnology and comprising three Upflow Anaerobic Sludge Blanket (UASB, 20m 3 each one) reactor, six High Rate Algal Ponds (HRAP, 32m 2 each one), and a Dissolved Air Flotation (DAF, 1m 3 ) unit. E. coli concentration was monitored at the effluent of the different units (UASB, HRAP, DAF) of the pilot WWTP. The efficiency of the SODIS process was studied for the inactivation of three of the commonly employed indicator microorganisms (Escherichia coli, Enterococcus spp. and Clostridium perfringens) using a compound parabolic collector (CPC) for five months under various conditions of irradiance and temperature. E. coli and Enterococcus spp. were more effectively disinfected by the SODIS unit (2.9 and 2.5 logarithms of reduction on average, respectively) than by the HRAP (2 and 1.1) or the DAF (0.9 and 0.1). On the contrary, the DAF technology achieved better reduction rates of C. perfringens (1.7) than the SODIS (0.9) and the HRAP (0.1). No regrowth of any microorganisms was detected during dark storage after the SODIS treatment. Incorporating a SODIS unit after the non-conventional WWTP processes substantially increases the possibilities for reuse of the treated water after receiving a cumulative UV radiation dose of 25W·h/m 2 (50min of normalized time of solar illumination). The surface requirement of the SODIS equipment would be 3.5 times smaller than the HRAP's surface. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

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

Xu, Suyun; Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region; Selvam, Ammaiyappan

Highlights: • Effect of micro-aeration on acidogenesis and hydrolysis of food waste was investigated. • Micro-aeration at 258 L-air/kg TS/d increased the VFAs production 3-fold. • High aeration leads to loss of substrate through microbial biomass and respiration. • Optimum aeration increased methane recovery while high aeration intensity reduced methane yield. - Abstract: Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization ofmore » food waste was evaluated at 35 °C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21–27% and 38–64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH{sub 4}/g VS{sub added} in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO{sub 2} respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.« less

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

PubMed

Buyukkamaci, Nurdan; Koken, Emre

2010-11-15

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

Enrichment of acetogenic bacteria in high rate anaerobic reactors under mesophilic and thermophilic conditions.

PubMed

Ryan, P; Forbes, C; McHugh, S; O'Reilly, C; Fleming, G T A; Colleran, E

2010-07-01

The objective of the current study was to expand the knowledge of the role of acetogenic Bacteria in high rate anaerobic digesters. To this end, acetogens were enriched by supplying a variety of acetogenic growth supportive substrates to two laboratory scale high rate upflow anaerobic sludge bed (UASB) reactors operated at 37 degrees C (R1) and 55 degrees C (R2). The reactors were initially fed a glucose/acetate influent. Having achieved high operational performance and granular sludge development and activity, both reactors were changed to homoacetogenic bacterial substrates on day 373 of the trial. The reactors were initially fed with sodium vanillate as a sole substrate. Although % COD removal indicated that the 55 degrees C reactor out performed the 37 degrees C reactor, effluent acetate levels from R2 were generally higher than from R1, reaching values as high as 5023 mg l(-1). Homoacetogenic activity in both reactors was confirmed on day 419 by specific acetogenic activity (SAA) measurement, with higher values obtained for R2 than R1. Sodium formate was introduced as sole substrate to both reactors on day 464. It was found that formate supported acetogenic activity at both temperatures. By the end of the trial, no specific methanogenic activity (SMA) was observed against acetate and propionate indicating that the methane produced was solely by hydrogenotrophic Archaea. Higher SMA and SAA values against H(2)/CO(2) suggested development of a formate utilising acetogenic population growing in syntrophy with hydrogenotrophic methanogens. Throughout the formate trial, the mesophilic reactor performed better overall than the thermophilic reactor. Copyright 2010 Elsevier Ltd. All rights reserved.

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

PubMed

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

2012-01-01

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

Application of molecular techniques to evaluate the methanogenic archaea and anaerobic bacteria in the presence of oxygen with different COD:sulfate ratios in a UASB reactor.

PubMed

Hirasawa, Julia Sumiko; Sarti, Arnaldo; Del Aguila, Nora Katia Saavedra; Varesche, Maria Bernadete A

2008-10-01

In this paper, the microbial characteristics of the granular sludge in the presence of oxygen (3.0+/-0.7 mg O2 l(-1)) were analyzed using molecular biology techniques. The granules were provided by an upflow anaerobic sludge blanket (UASB) operated over 469 days and fed with synthetic substrate. Ethanol and sulfate were added to obtain different COD/SO4(2-) ratios (3.0, 2.0, and 1.6). The results of fluorescent in situ hybridization (FISH) analyses showed that archaeal cells, detected by the ARC915 probe, accounted for 77%, 84%, and 75% in the COD/SO(4)(2-) ratios (3.0, 2.0, and 1.6, respectively). Methanosaeta sp. was the predominant acetoclastic archaea observed by optical microscopy and FISH analyses, and confirmed by sequencing of the excised bands of the DGGE gel with a similarity of 96%. The sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris (similarity of 99%) was verified by sequencing of the DGGE band. Others identified microorganism were similar to Shewanella sp. and Desulfitobacterium hafniense, with similarities of 95% and 99%, respectively. These results confirmed that the presence of oxygen did not severely affect the metabolism of microorganisms that are commonly considered strictly anaerobic. We obtained mean efficiencies of organic matter conversion and sulfate reducing higher than 74%.

Biological treatment of TMAH (tetra-methyl ammonium hydroxide) in a full-scale TFT-LCD wastewater treatment plant.

PubMed

Hu, Tai-Ho; Whang, Liang-Ming; Liu, Pao-Wen Grace; Hung, Yu-Ching; Chen, Hung-Wei; Lin, Li-Bin; Chen, Chia-Fu; Chen, Sheng-Kun; Hsu, Shu Fu; Shen, Wason; Fu, Ryan; Hsu, Romel

2012-06-01

This study evaluated biological treatment of TMAH in a full-scale methanogenic up-flow anaerobic sludge blanket (UASB) followed by an aerobic bioreactor. In general, the UASB was able to perform a satisfactory TMAH degradation efficiency, but the effluent COD of the aerobic bioreactor seemed to increase with an increased TMAH in the influent wastewater. The batch test results confirmed that the UASB sludge under methanogenic conditions would be favored over the aerobic ones for TMAH treatment due to its superb ability of handling high strength of TMAH-containing wastewaters. Based on batch experiments, inhibitory chemicals present in TFT-LCD wastewater like surfactants and sulfate should be avoided to secure a stable methanogenic TMAH degradation. Finally, molecular monitoring of Methanomethylovorans hollandica and Methanosarcina mazei in the full-scale plant, the dominant methanogens in the UASB responsible for TMAH degradation, may be beneficial for a stable TMAH treatment performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

PubMed

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

2016-01-01

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

Toluene inhibition on an anaerobic reactor sludge in terms of potential activity and composition of acetoclastic methanogens.

PubMed

Ince, Orhan; Kolukirik, Mustafa; Cetecioglu, Zeynep; Eyice, Ozge; Inceoglu, Ozgul; Ince, Bahar

2009-12-01

The aim of this study was to determine the effect of toluene on an anaerobic sludge taken from a full-scale upflow anaerobic sludge blanket (UASB) reactor in terms of potential activity and composition of acetoclastic methanogens. Specific methanogenic activity (SMA) test results showed that 5%, 9.5%, 14%, 24%, 29%, 38% and 62% inhibition occurred in the potential methane production (PMP) rate of the sludge at toluene concentrations of 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, 0.5 mM, 0.6 mM and 1 mM, respectively. Fluorescence in situ hybridization (FISH) results showed that relative abundance of archaeal cells was approx. 19% throughout the SMA tests. The anaerobic sludge was dominated by acetoclastic genus Methanosaeta which were slightly affected by increasing toluene concentrations do not have any effect on relative abundance of Methanosaeta spp., which was between 73% +/- 1.6 and 68% +/- 2.1 of the archaeal population.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

PubMed Central

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-01-01

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria. PMID:26555802

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor.

PubMed

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-10-15

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Compared microbiology of granular sludge under autotrophic, mixotrophic and heterotrophic denitrification conditions.

PubMed

Fernández, N; Sierra-Alvarez, R; Amils, R; Field, J A; Sanz, J L

2009-01-01

Water contamination by nitrate is a wideworld extended phenomena. Biological autotrophic denitrification has a real potential to face this problem and presents less drawbacks than the most extended heterotrophic denitrification. Three bench-scale UASB reactors were operated under autotrophic (R1, H2S as electron donor), mixotrophic (R2, H2S plus p-cresol as electron donors) and heterotrophic (R3, p-cresol as electron donor) conditions using nitrate as terminal electron acceptor. 16S rDNA genetic libraries were built up to compare their microbial biodiversity. Six different bacteria phyla and three archaeal classes were observed. Proteobacteria was the main phyla in all reactors standing out the presence of denitrifiers. Microorganisms similar to Thiobacillus denitrificans and Acidovorax sp. performed the autotrophic denitification. These OTUs were displaced by chemoheterotrophic denitrifiers, especially by Limnobacter-like and Ottowia-like OTUs. Other phyla were Bacteroidetes, Chloroflexi, Firmicutes and Actinobacteria that--as well as Archaea members--were implicated in the degradation of organic matter, as substrate added as coming from endogenous sludge decay under autotrophic conditions. Archaea diversity remained low in all the reactors being Methanosaeta concilii the most abundant one.

Biogas production from Jatropha curcas press-cake

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

Staubmann, R.; Guebitz, G.M.; Lafferty, R.M.

Seeds of the tropical plant Jatropha curcas (purge nut, physic nut) are used for the production of oil. Several methods for oil extraction have been developed. In all processes, about 50% of the weight of the seeds remain as a press cake containing mainly protein and carbohydrates. Investigations have shown that this residue contains toxic compounds and cannot be used as animal feed without further processing. Preliminary experiments have shown that the residue is a good substrate for biogas production. Biogas formation was studied using a semicontinous upflow anaerobic sludge blanket (UASB) reactor; a contact-process and an anaerobic filter eachmore » reactor having a total volume of 110 L. A maximum production rate of 3.5 m{sup 3} m{sup -3} d{sup -1} was obtained in the anaerobic filter with a loading rate of 13 kg COD m{sup -3} d{sup -1}. However, the UAS reactor and the contact-process were not suitable for using this substrate. When using an anaerobic filter with Jatropha curcas seed cake as a substrate, 76% of the COD was degraded and 1 kg degraded COD yielded 355 L of biogas containing 70% methane. 28 refs., 3 figs., 4 tabs.« less

Characterization and anaerobic treatment of the sanitary landfill leachate in Istanbul.

PubMed

Inanc, B; Calli, B; Saatci, A

2000-01-01

In this study, characterization and anaerobic treatability of leachate from Komurcuoda Sanitary Landfill located on the Asian part of Istanbul were investigated. Time based fluctuations in characteristics of leachate were monitored for an 8 month period. Samples were taken from a 200 m3 holding tank located at the lowest elevation of the landfill. COD concentrations have ranged between 18,800 and 47,800 mg/l while BOD5 between 6820 and 38,500 mg/L. COD and BOD5 values were higher in summer and lower in winter due to dilution by precipitation. On the other hand, it was quite interesting that such a dilution effect was not observed for ammonia. The highest ammonia concentration, 2690 mg/L was in November 1998. BOD5/COD ratio was larger than 0.7 for most samples indicating high biodegradability, and acidic phase of decomposition in the landfill. For anaerobic treatability, three different reactors, namely an upflow anaerobic sludge bed reactor, an anaerobic upflow filter and a hybrid bed reactor, were used. The anaerobic reactors were operated for more than 230 days and were continuing operation when this paper was prepared. Organic loading was increased gradually from 1.3 kg COD/m3.day to 8.2 kg COD/m3.day while hydraulic retention time was reduced from 2.4 days to 2.0 days. All the reactors showed similar performances against organic loadings with efficiencies between 80% and 90%. However the reactors have experienced high ammonia concentrations several times throughout the experimental period, and showed different inhibition levels. Anaerobic filter was the least affected reactor while UASB was the most. Hybrid bed reactor has exhibited a similar performance to anaerobic filter although not to the same degree.

Biomethanation under psychrophilic conditions.

PubMed

Dhaked, Ram Kumar; Singh, Padma; Singh, Lokendra

2010-12-01

The biomethanation of organic matter represents a long-standing, well-established technology. Although at mesophilic and thermophilic temperatures the process is well understood, current knowledge on psychrophilic biomethanation is somewhat scarce. Methanogenesis is particularly sensitive to temperature, which not only affects the activity and structure of the microbial community, but also results in a change in the degradation pathway of organic matter. There is evidence of psychrophilic methanogenesis in natural environments, and a number of methanogenic archaea have been isolated with optimum growth temperatures of 15-25 °C. At psychrophilic temperatures, large amounts of heat are needed to operate reactors, thus resulting in a marginal or negative overall energy yield. Biomethanation at ambient temperature can alleviate this requirement, but for stable biogas production, a microbial consortium adapted to low temperatures or a psychrophilic consortium is required. Single-step or two-step high rate anaerobic reactors [expanded granular sludge bed (EGSB) and up flow anaerobic sludge bed (UASB)] have been used for the treatment of low strength wastewater. Simplified versions of these reactors, such as anaerobic sequencing batch reactors (ASBR) and anaerobic migrating blanket reactor (AMBR) have also been developed with the aim of reducing volume and cost. This technology has been further simplified and extended for the disposal of night soil in high altitude, low temperature areas of the Himalayas, where the hilly terrain, non-availability of conventional energy, harsh climate and space constraints limit the application of complicated reactors. Biomethanation at psychrophilic temperatures and the contribution made to night-soil degradation in the Himalayas are reviewed in this article. Copyright © 2010 Elsevier Ltd. All rights reserved.

Bioelectrochemical enhancement of anaerobic methanogenesis for high organic load rate wastewater treatment in a up-flow anaerobic sludge blanket (UASB) reactor.

PubMed

Zhao, Zhiqiang; Zhang, Yaobin; Chen, Shuo; Quan, Xie; Yu, Qilin

2014-10-17

A coupling process of anaerobic methanogenesis and electromethanogenesis was proposed to treat high organic load rate (OLR) wastewater. During the start-up stage, acetate removal efficiency of the electric-biological reactor (R1) reached the maximization about 19 percentage points higher than that of the control anaerobic reactor without electrodes (R2), and CH4 production rate of R1 also increased about 24.9% at the same time, while additional electric input was 1/1.17 of the extra obtained energy from methane. Coulombic efficiency and current recorded showed that anodic oxidation contributed a dominant part in degrading acetate when the metabolism of methanogens was low during the start-up stage. Along with prolonging operating time, aceticlastic methanogenesis gradually replaced anodic oxidation to become the main pathway of degrading acetate. When the methanogens were inhibited under the acidic conditions, anodic oxidation began to become the main pathway of acetate decomposition again, which ensured the reactor to maintain a stable performance. FISH analysis confirmed that the electric field imposed could enrich the H2/H(+)-utilizing methanogens around the cathode to help for reducing the acidity. This study demonstrated that an anaerobic digester with a pair of electrodes inserted to form a coupling system could enhance methanogenesis and reduce adverse impacts.

Effect of influent COD/SO4(2-) ratios on UASB treatment of a synthetic sulfate-containing wastewater.

PubMed

Hu, Yong; Jing, Zhaoqian; Sudo, Yuta; Niu, Qigui; Du, Jingru; Wu, Jiang; Li, Yu-You

2015-07-01

The effect of the chemical oxygen demand/sulfate (COD/SO4(2-)) ratio on the anaerobic treatment of synthetic chemical wastewater containing acetate, ethanol, and sulfate, was investigated using a UASB reactor. The experimental results show that at a COD/SO4(2-) ratio of 20 and a COD loading rate of 25.2gCODL(-1)d(-1), a COD removal of as high as 87.8% was maintained. At a COD/SO4(2-) ratio of 0.5 (sulfate concentration 6000mgL(-1)), however, the COD removal was 79.2% and the methane yield was 0.20LCH4gCOD(-1). The conversion of influent COD to methane dropped from 80.5% to 54.4% as the COD/SO4(2-) ratio decreased from 20 to 0.5. At all the COD/SO4(2-) ratios applied, over 79.4% of the total electron flow was utilized by methane-producing archaea (MPA), indicating that methane fermentation was the predominant reaction. The majority of the methane was produced by acetoclastic MPA at high COD/SO4(2-) ratios and both acetoclastic and hydrogenthrophic MPA at low COD/SO4(2-) ratios. Only at low COD/SO4(2-) ratios were SRB species such as Desulfovibrio found to play a key role in ethanol degradation, whereas all the SRB species were found to be incomplete oxidizers at both high and low COD/SO4(2-) ratios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Behaviour of molecular weight distribution for the liquid fraction of pig slurry treated by anaerobic digestion.

PubMed

Rodríguez, D C; Belmonte, M; Peñuela, G; Campos, J L; Vidal, G

2011-01-01

Pig slurry was treated in an upflow anaerobic sludge blanket (UASB) reactor. To maintain a stable operation, the organic loading rate (OLR) applied to the system was increased stepwise by decreasing the dilution ratio of the pig slurry. Finally, during the last operational stage, no dilution was applied to the influent. The reactor maintained a soluble chemical oxygen demand (CODs) removal efficiency of 82% when OLRs lower than 1.73 g CODs l(-1) d(-1) were applied, although its efficiency fell to 55% when operated at 2.48 g CODs l(-1) d(-1). System performance was not affected by the presence of free ammonia (concentrations up to 375 mg NH3 l(-1)). The distribution of the different molecular weight fractions changed significantly during anaerobic digestion. Proteins contained in the fractions higher than 10,000 Daltons are less degraded than those belonging to the lower fractions. An important percentage of both COD and BOD5 in the effluent were observed in the lowest fraction, probably caused by the presence of volatile fatty acids (VFA).

Anaerobic digestion of alkaline bleaching wastewater from a kraft pulp and paper mill using UASB technique.

PubMed

Larsson, Madeleine; Truong, Xu-Bin; Björn, Annika; Ejlertsson, Jörgen; Bastviken, David; Svensson, Bo H; Karlsson, Anna

2015-01-01

Anaerobic digestion of alkaline kraft elemental chlorine-free bleaching wastewater in two mesophilic, lab-scale upflow anaerobic sludge bed reactors resulted in significantly higher biogas production (250±50 vs. 120±30 NmL g [Formula: see text]) and reduction of filtered total organic carbon (fTOC) (60±5 vs. 43±6%) for wastewater from processing of hardwood (HW) compared with softwood (SW). In all cases, the gas production was likely underestimated due to poor gas separation in the reactors. Despite changes in wastewater characteristics, a stable anaerobic process was maintained with hydraulic retention times (HRTs) between 7 and 14 h. Lowering the HRT (from 13.5 to 8.5 h) did not significantly affect the process, and the stable performance at 8.5 h leaves room for further decreases in HRT. The results show that this type of wastewater is suitable for a full-scale implementation, but the difference in methane potential between SW and HW is important to consider both regarding process dimensioning and biogas yield optimization.

Autoclaved sludge as the ideal seed to culture anammox bacteria: Reactor performance and microbial community diversity.

PubMed

Wang, Yu; Bu, Cui-Na; Kang, Qi; Ahmad, Hafiz Adeel; Zhang, Jian; Gao, Baoyu; Ni, Shou-Qing

2017-11-01

Reducing activity of commensal bacteria in inocula may enhance anammox bacteria proliferation and realization of anammox process. Fast start-up of anammox process in an UASB reactor was successfully achieved by using autoclaved sludge (anaerobic granular sludge pretreated by autoclaving) and 0.3% active anammox sludge as inoculum. Continuous experiments indicated that R2 (autoclaved sludge addition) could shorten the start-up period from 72days to 63days. The first 50days anammox population specific growth rates (μ) of R1 (the control) and R2 were determined to be 0.014d -1 and 0.045d -1 using q-PCR assays. Analysis of coefficient of variations of nitrogen removal performance during days 96-225 indicated that R2 was more stable than R1. The Illumina MiSeq sequencing showed that autoclaving could decrease microbial diversity of sludge and enhance the abundance of anammox bacteria. Furthermore, PICRUSt community functions forecast and c-di-GMP measure illuminated the result of higher stability in R2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coproduction of hydrogen and methane via anaerobic fermentation of cornstalk waste in continuous stirred tank reactor integrated with up-flow anaerobic sludge bed.

PubMed

Cheng, Xi-Yu; Li, Qian; Liu, Chun-Zhao

2012-06-01

A 10 L continuous stirred tank reactor (CSTR) system was developed for a two-stage hydrogen fermentation process with an integrated alkaline treatment. The maximum hydrogen production rate reached 218.5 mL/L h at a cornstalk concentration of 30 g/L, and the total hydrogen yield and volumetric hydrogen production rate reached 58.0 mL/g-cornstalk and 0.55-0.57 L/L d, respectively. A 10 L up-flow anaerobic sludge bed (UASB) was used for continuous methane fermentation of the effluents obtained from the two-stage hydrogen fermentation. At the optimal organic loading rate of 15.0 g-COD/Ld, the COD removal efficiency and volumetric biogas production rate reached 83.3% and 4.6L/Ld, respectively. Total methane yield reached 200.9 mL/g-cornstalk in anaerobic fermentation with the effluents and alkaline hydrolysate. As a result, the total energy recovery by coproduction of hydrogen and methane with anaerobic fermentation of cornstalk reached 67.1%. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Increasing Interest of ANAMMOX Research in China: Bacteria, Process Development, and Application

PubMed Central

Chai, Li-Yuan; Tang, Chong-Jian; Zheng, Ping; Min, Xiao-Bo; Yang, Zhi-Hui; Song, Yu-Xia

2013-01-01

Nitrogen pollution created severe environmental problems and increasingly has become an important issue in China. Since the first discovery of ANAMMOX in the early 1990s, this related technology has become a promising as well as sustainable bioprocess for treating strong nitrogenous wastewater. Many Chinese research groups have concentrated their efforts on the ANAMMOX research including bacteria, process development, and application during the past 20 years. A series of new and outstanding outcomes including the discovery of new ANAMMOX bacterial species (Brocadia sinica), sulfate-dependent ANAMMOX bacteria (Anammoxoglobus sulfate and Bacillus benzoevorans), and the highest nitrogen removal performance (74.3–76.7 kg-N/m3/d) in lab scale granule-based UASB reactors around the world were achieved. The characteristics, structure, packing pattern and floatation mechanism of the high-rate ANAMMOX granules in ANAMMOX reactors were also carefully illustrated by native researchers. Nowadays, some pilot and full-scale ANAMMOX reactors were constructed to treat different types of ammonium-rich wastewater including monosodium glutamate wastewater, pharmaceutical wastewater, and leachate. The prime objective of the present review is to elucidate the ongoing ANAMMOX research in China from lab scale to full scale applications, comparative analysis, and evaluation of significant findings and to set a design to usher ANAMMOX research in culmination. PMID:24381935

Biological sulfate removal from construction and demolition debris leachate: effect of bioreactor configuration.

PubMed

Kijjanapanich, Pimluck; Do, Anh Tien; Annachhatre, Ajit P; Esposito, Giovanni; Yeh, Daniel H; Lens, Piet N L

2014-03-30

Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75-85% was achieved at a hydraulic retention time (HRT) of 15.5h. A high calcium concentration up to 1,000 mg L(-1) did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Experience with the design and start up of two full-scale UASB plants in Brazil: enhancements and drawbacks.

PubMed

Chernicharo, C A L; Almeida, P G S; Lobato, L C S; Couto, T C; Borges, J M; Lacerda, Y S

2009-01-01

This paper discusses the main drawbacks and enhancements experienced with the design and start up of two full-scale UASB plants in Brazil. The topics addressed are related to blockage of inlet pipes, scum accumulation, seed sludge for the start-up, corrosion and gas leakage, odour generation and sludge management. The paper describes the main improvements achieved.

Combined anaerobic-aerobic treatment of landfill leachates under mesophilic, submesophilic and psychrophilic conditions.

PubMed

Kalyuzhnyi, S; Gladchenko, M; Epov, A

2003-01-01

As a first step of treatment of landfill leachates (total COD--1,430-3,810 mg/l, total nitrogen 90-162 mg/l), a performance of laboratory UASB reactors has been investigated under mesophilic (30 degrees C), sub-mesophilic (20 degrees C) and psychrophilic (10 degrees C) conditions. Under hydraulic retention times (HRT) of around 7 h, when the average organic loading rates (OLR) were around 5 g COD/l/day, the total COD removal accounted for 81% (on the average) with the effluent concentrations close to anaerobic biodegradability limit (0.25 g COD/l) for mesophilic and sub-mesophilic regimes. The psychrophilic treatment conducted under the average HRT of 8 h and the average OLR of 4.22 g COD/l/day showed a total COD removal of 47% producing the effluents (0.75 g COD/l) more suitable for subsequent biological nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulphides inside the sludge bed. The application of aerobic/anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.

Anaerobic bioprocessing of organic wastes.

PubMed

Verstraete, W; de Beer, D; Pena, M; Lettinga, G; Lens, P

1996-05-01

Anaerobic digestion of dissolved, suspended and solid organics has rapidly evolved in the last decades but nevertheless still faces several scientific unknowns. In this review, some fundamentals of bacterial conversions and adhesion are addressed initially. It is argued in the light of ΔG-values of reactions, and in view of the minimum energy quantum per mol, that anaerobic syntrophs must have special survival strategies in order to support their existence: redistributing the available energy between the partners, reduced end-product fermentation reactions and special cell-to-cell physiological interactions. In terms of kinetics, it appears that both reaction rates and residual substrate thresholds are strongly related to minimum ΔG-values. These new fundamental insights open perspectives for efficient design and operation of anaerobic bioprocesses. Subsequently, an overview is given of the current anaerobic biotechnology. For treating wastewaters, a novel and high performance new system has been introduced during the last decade; the upflow anaerobic sludge blanket system (UASB). This reactor concept requires anaerobic consortia to grow in a dense and eco-physiologically well-organized way. The microbial principles of such granular sludge growth are presented. Using a thermodynamic approach, the formation of different types of aggregates is explained. The application of this bioprocess in worldwide wastewater treatment is indicated. Due to the long retention times of the active biomass, the UASB is also suitable for the development of bacterial consortia capable of degrading xenobiotics. Operating granular sludge reactors at high upflow velocities (5-6 m/h) in expanded granular sludge bed (EGSB) systems enlarges the application field to very low strength wastewaters (chemical oxygen demand < 1 g/l) and psychrophilic temperatures (10°C). For the treatment of organic suspensions, there is currently a tendency to evolve from the conventional mesophilic continuously stirred tank system to the thermophilic configuration, as the latter permits higher conversion rates and easier sanitation. Integration of ultrafiltration in anaerobic slurry digestion facilitates operation at higher volumetric loading rates and at shorter residence times. With respect to organic solids, the recent trend in society towards source separated collection of biowaste has opened a broad range of new application areas for solid state anaerobic fermentation.

A feasibility study on biological nitrogen removal (BNR) via integrated thiosulfate-driven denitratation with anammox.

PubMed

Qian, Jin; Zhang, Mingkuan; Wu, Yaoguo; Niu, Juntao; Chang, Xing; Yao, Hairui; Hu, Sihai; Pei, Xiangjun

2018-06-12

To exploit the advantages of less electron donor consumptions in partial-denitrification (denitratation, NO 3 - → NO 2 - ) as well as less sludge production in autotrophic denitrification (AD) and anammox, a novel biological nitrogen removal (BNR) process through combined anammox and thiosulfate-driven denitratation was proposed here. In this study, the ratio of S 2 O 3 2- -S/NO 3 - -N and pH are confirmed to be two key factors affecting the thiosulfate-driven denitratation activity and nitrite accumulation. Simultaneous high denitratation activity and substantial nitrite accumulation were observed at initial S 2 O 3 2- -S/NO 3 - -N ratio of 1.5:1 and pH of 8.0. The optimal pH for the anammox reaction is determined to be 8.0. A sequential batch reactor (SBR) and an up-flow anaerobic sludge blanket (UASB) reactor were established to proceed the anammox and the high-rate thiosulfate-driven denitratation, respectively. Under the ambient temperature of 35 °C, the total nitrogen removal efficiency and capacity are 73% and 0.35 kg N/day/m 3 in the anammox-SBR. At HRT of 30 min, the NO 3 - removal efficiency could achieve above 90% with the nitrate-to-nitrite transformation ratio of 0.8, implying the great potential to apply the thiosulfate-driven denitratation & anammox system for BNR with minimal sludge production. Without the occurrence of denitritation (NO 2 - → N 2 O → N 2 ), theoretically no N 2 O could be emitted from this BNR system. This study could shed light on how to operate a high rate BNR system targeting to electron donor and energy savings as well as biowastes minimization and greenhouse gas reductions. Copyright © 2018. Published by Elsevier Ltd.

Continuous hydrogen and methane production from Agave tequilana bagasse hydrolysate by sequential process to maximize energy recovery efficiency.

PubMed

Montiel Corona, Virginia; Razo-Flores, Elías

2018-02-01

Continuous H 2 and CH 4 production in a two-stage process to increase energy recovery from agave bagasse enzymatic-hydrolysate was studied. In the first stage, the effect of organic loading rate (OLR) and stirring speed on volumetric hydrogen production rate (VHPR) was evaluated in a continuous stirred tank reactor (CSTR); by controlling the homoacetogenesis with the agitation speed and maintaining an OLR of 44 g COD/L-d, it was possible to reach a VHPR of 6 L H 2 /L-d, equivalent to 1.34 kJ/g bagasse. In the second stage, the effluent from CSTR was used as substrate to feed a UASB reactor for CH 4 production. Volumetric methane production rate (VMPR) of 6.4 L CH 4 /L-d was achieved with a high OLR (20 g COD/L-d) and short hydraulic retention time (HRT, 14 h), producing 225 mL CH 4 /g-bagasse equivalent to 7.88 kJ/g bagasse. The two-stage continuous process significantly increased energy conversion efficiency (56%) compared to one-stage hydrogen production (8.2%). Copyright © 2017 Elsevier Ltd. All rights reserved.

Conversion of (Meth)acrylic acids to methane granular sludge: Initiation by specific anerobic microflora

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

Shtarkman, N.B.; Obraztova, A.Y.; Laurinavichyus, K.S.

1995-03-01

The role of a specific anaerobic microflora in the initiation of degradation of (meth)acrylic acids to methane by granular sludge from a UASB reactor was investigated. Associations of anaerobic bacteria isolated from the anaerobic sludge, which was used for a long time for treatment of wastewater from (meth)acrylate production, were able to realize the initial stage of (meth)acrylic acid decomposition, i.e., a conversion of acrylic and methacrylic acids to propionic and isobutyric acids, respectively. When added to granules, these association played a role of an {open_quotes}initiator{close_quotes} of the degradation process, which was then continued by the granular sludge microflora utilizingmore » propionate and isobutyrate. Some characteristics of the granules adapted to propionate or isobutyrate are presented. The rates of propionate and isobutyrate consumption by adapted granules is, respectively, 21 and 53 times higher than the values obtained for nonadapted granules. A combined use of {open_quotes}initiating{close_quotes} bacteria and adapted granules provided degradation of (meth)acrylic acids with a maximum methane yield. The possibility is discussed of employing the granules, which are adapted to short-chain fatty acids, and the {open_quotes}initiating{close_quotes} bacteria, which accomplish the initial steps of the organic material decomposition to lower fatty acids, for the conversion of various chemical compounds to methane. 10 refs., 3 figs., 2 tabs.« less

Anaerobic treatment of antibiotic production wastewater pretreated with enhanced hydrolysis: Simultaneous reduction of COD and ARGs.

PubMed

Yi, Qizhen; Zhang, Yu; Gao, Yingxin; Tian, Zhe; Yang, Min

2017-03-01

The presence of high concentration antibiotics in wastewater can disturb the stability of biological wastewater treatment systems and promote generation of antibiotic resistance genes (ARGs) during the treatment. To solve this problem, a pilot system consisting of enhanced hydrolysis pretreatment and an up-flow anaerobic sludge bed (UASB) reactor in succession was constructed for treating oxytetracycline production wastewater, and the performance was evaluated in a pharmaceutical factory in comparison with a full-scale anaerobic system operated in parallel. After enhanced hydrolysis under conditions of pH 7 and 85 °C for 6 h, oxytetracycline production wastewater with an influent chemical oxygen demand (COD) of 11,086 ± 602 mg L -1 was directly introduced into the pilot UASB reactor. With the effective removal of oxytetracycline and its antibacterial potency (from 874 mg L -1 to less than 0.61 mg L -1 and from 900 mg L -1 to less than 0.84 mg L -1 , respectively) by the enhanced hydrolysis pretreatment, an average COD removal rate of 83.2%, 78.5% and 68.9% was achieved at an organic loading rate of 3.3, 4.8 and 5.9 kg COD m -3  d -1 , respectively. At the same time, the relative abundances of the total tetracycline (tet) genes and a mobile element (Class 1 integron (intI1)) in anaerobic sludge on day 96 were one order of magnitude lower than those in inoculated sludge on day 0 (P < 0.01). The reduction of ARGs was further demonstrated by metagenomic sequencing. By comparison, the full-scale anaerobic system treating oxytetracycline production wastewater with an influent COD of 3720 ± 128 mg L -1 after dilution exhibited a COD removal of 51 ± 4% at an organic loading rate (OLR) 1.2 ± 0.2 kg m -3  d -1 , and a total tet gene abundance in sludge was five times higher than the pilot-scale system (P < 0.01). The above result demonstrated that enhanced hydrolysis as a pretreatment method could enable efficient anaerobic treatment of oxytetracycline production wastewater containing high concentrations of oxytetracycline with significantly lower generation of ARGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

PubMed Central

Doloman, Anna; Soboh, Yousef; Walters, Andrew J.; Sims, Ronald C.

2017-01-01

Anaerobic digestion (AD) is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment. PMID:29259629

The effect of enzymatic pre-hydrolysis of dairy wastewater on the granular and immobilized microbial community in anaerobic bioreactors.

PubMed

Cammarota, Magali C; Rosa, Daniela R; Duarte, Iolanda C S; Saavedra, Nora K; Varesche, Maria B A; Zaiat, Marcelo; Freire, Denise M G

2013-01-01

The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-state fermentation was evaluated in two anaerobic bioreactors (up-flow anaerobic sludge blanket (UASB) and horizontal-flow anaerobic immobilized biomass (HAIB)) treating dairy wastewater with 1200 mg oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of the solid enzymatic preparation at 30 degrees C for 24 h. This resulted in a final concentration of free acids eight times higher than the initial value. The bioreactors operated at 30 degrees C with hydraulic retention times of 12 h (HAIB) and 20 h (UASB) for a period of 430 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. There was, however, an increase in the effluent oil and grease concentration (from values as low as 17 mg/L to values above 150 mg/L in the UASB bioreactor, and from 38-242 mg/L in the HAIB bioreactor), and oil and grease accumulation in the biomass throughout the operational period (the oil and grease content reached 1.7 times that found in the inoculum of the UASB bioreactor). The HAIB bioreactor gave better results because the support for biomass immobilization acted as a filter, retaining oil and grease at the entry of the bioreactor. The molecular analysis of the Bacteria and Archaea domains revealed significant differences in the microbial profiles in experiments conducted with and without the pre-hydrolysis step. The differences observed in the overall parameters could be related to the microbial diversity of the anaerobic sludge.

Evaluation and thermodynamic calculation of ureolytic magnesium ammonium phosphate precipitation from UASB effluent at pilot scale.

PubMed

Desmidt, E; Ghyselbrecht, K; Monballiu, A; Verstraete, W; Meesschaert, B D

2012-01-01

The removal of phosphate as magnesium ammonium phosphate (MAP, struvite) has gained a lot of attention. A novel approach using ureolytic MAP crystallization (pH increase by means of bacterial ureases) has been tested on the anaerobic effluent of a potato processing company in a pilot plant and compared with NuReSys(®) technology (pH increase by means of NaOH). The pilot plant showed a high phosphate removal efficiency of 83 ± 7%, resulting in a final effluent concentration of 13 ± 7 mg · L(-1) PO(4)-P. Calculating the evolution of the saturation index (SI) as a function of the remaining concentrations of Mg(2+), PO(4)-P and NH(4)(+) during precipitation in a batch reactor, resulted in a good estimation of the effluent PO(4)-P concentration of the pilot plant, operating under continuous mode. X-ray diffraction (XRD) analyses confirmed the presence of struvite in the small single crystals observed during experiments. The operational cost for the ureolytic MAP crystallization treating high phosphate concentrations (e.g. 100 mg · L(-1) PO(4)-P) was calculated as 3.9 € kg(-1) P(removed). This work shows that the ureolytic MAP crystallization, in combination with an autotrophic nitrogen removal process, is competitive with the NuReSys(®) technology in terms of operational cost and removal efficiency but further research is necessary to obtain larger crystals.

Effect of multiwalled carbon nanotubes on UASB microbial consortium.

PubMed

Yadav, Tushar; Mungray, Alka A; Mungray, Arvind K

2016-03-01

The continuous rise in production and applications of carbon nanotubes (CNTs) has grown a concern about their fate and toxicity in the environment. After use, these nanomaterials pass through sewage and accumulate in wastewater treatment plants. Since, such plants rely on biological degradation of wastes; their activity may decrease due to the presence of CNTs. This study investigated the effect of multiwalled carbon nanotubes (MWCNTs) on upflow anaerobic sludge blanket (UASB) microbial activity. The toxic effect on microbial viability, extracellular polymeric substances (EPS), volatile fatty acids (VFA), and biogas generation was determined. The reduction in a colony-forming unit (CFU) was 29 and 58 % in 1 and 100 mg/L test samples, respectively, as compared to control. The volatile fatty acids and biogas production was also found reduced. The scanning electron microscopy (SEM) and fluorescent microscopy images confirmed that the MWCNT mediated microbial cell damage. This damage caused the increase in EPS carbohydrate, protein, and DNA concentration. Fourier transform infrared (FTIR) spectroscopy results supported the alterations in sludge EPS due to MWCNT. Our observations offer a new insight to understand the nanotoxic effect of MWCNTs on UASB microflora in a complex environment system.

Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.

PubMed

Luostarinen, S; Rintala, J

2006-01-01

Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10-20 degrees C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 degrees C. Removal of total chemical oxygen demand (COD1) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperature decrease had little effect on COD removals, though the need for phase 2 increased with decreasing temperature, especially with BWKW. Post-treatment of BWKW in MBBR resulted in approx. 50% nitrogen removal, but suffered from lack of carbon for denitrification. With carbon addition, removal of ca. 83% was achieved.

Poultry slaughterhouse wastewater treatment plant for high quality effluent.

PubMed

Del Nery, V; Damianovic, M H Z; Moura, R B; Pozzi, E; Pires, E C; Foresti, E

2016-01-01

This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mg N-NH3 and phosphorus concentration of 1.34 ± 0.93 mg PO4(-3)/L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.

Post-treatment of UASB reactor effluent in waste stabilization ponds and in horizontal flow constructed wetlands: a comparative study in pilot scale in Southeast Brazil.

PubMed

Bastos, R K X; Calijuri, M L; Bevilacqua, P D; Rios, E N; Dias, E H O; Capelete, B C; Magalhães, T B

2010-01-01

The results of a 20-month period study in Brazil were analyzed to compare horizontal-flow constructed wetlands (CW) and waste stabilization pond (WSP) systems in terms of land area requirements and performance to produce effluent qualities for surface water discharge, and for wastewater use in agriculture and/or aquaculture. Nitrogen, E. coli and helminth eggs were more effectively removed in WSP than in CW. It is indicated that CW and WSP require similar land areas to achieve a bacteriological effluent quality suitable for unrestricted irrigation (10(3) E. coli per 100 mL), but CW would require 2.6 times more land area than ponds to achieve quite relaxed ammonia effluent discharge standards (20 mg NH(3) L(-1)), and, by far, more land than WSP to produce an effluent complying with the WHO helminth guideline for agricultural use (< or =1 egg per litre).

Co-digestion of ruminal content and blood from slaughterhouse industries: influence of solid concentration and ammonium generation.

PubMed

López, I; Passeggi, M; Borzacconi, L

2006-01-01

At the present time, organic solid wastes from industries and agricultural activities are considered to be promising substrates for biogas production via anaerobic digestion. Moreover solids stabilisation is required before reutilization or disposal. Slaughterhouses are among the most important industries in Uruguay and produce 150,000 tons of ruminal content (RC) and 30,000 tons of blood per year. In order to determine the influence of the solids and blood contents, the ammonia inhibition and the inoculum adaptation co-digestion batch tests were performed. A set of experiences with TS concentration of 2.5%, 5% and 7.5% and different ratios of RC/blood were carried out using an inoculum from an UASB reactor. In all experiences fast blood hydrolisation was observed. A higher methane production was detected in the experiences with higher TS content. However, the fraction of solids degradation was lower in these experiences. A plateau in the biogas production was found. The free ammonia level, which was above the reported inhibitory levels, could explain this behaviour. After the inhibition period the biogas production restarted probably due to the biomass acclimatisation to the ammonia. In order to determine the inoculum adaptation a new experiment was performed. The inoculum used was the sludge coming from the first set of experiences. Based upon batch tests a 3.5 m3 pilot reactor was designed and started up. Ammonia inhibition was avoided by the start-up strategy and in two weeks the biogas production was 3.5 m3/d. The VS stabilisation with a solid retention time of 20 days was of 43%. The pilot reactor working at steady state had a TS concentration of 3-4% with a ratio of RC/blood of 10:1 at the entrance.

Fate of oestrogens during anaerobic blackwater treatment with micro-aerobic post-treatment.

PubMed

de Mes, T Z D; Kujawa-Roeleveld, K; Zeeman, G; Lettinga, G

2007-01-01

The fate of oestrone (E1), 17beta-oestradiol (E2) and 17alpha-ethynyloestradiol (EE2) was investigated in a concentrated blackwater treatment system consisting of an UASB septic tank, with micro-aerobic post-treatment. In UASB septic tank effluent a (natural) total concentration of 4.02 microg/L E1 and 18.69 microg/L E2, comprising the sum of conjugated (>70% for E1 and >80% for E2) and unconjugated forms, was measured. During post-treatment the unconjugated oestrogens were removed to below 1 microg/L. A percentage of 77% of the measured unconjugated E1 and 82% of E2 was associated with particles >1.2 microm in the final effluent implying high sorption affinity of both compounds. When spiking the UASB septic tank effluent with E1, E2, EE2 and the sulphate conjugate of E2, removal in the micro-aerobic post-treatment was >99% for both E2 and EE2 and 83% for E1. The lower removal value for E1 was a result of (slow) deconjugation during the treatment, and in the final effluent still 40% of E1 and 99% of E2 was present in conjugated form. The latter was the result of incomplete deconjugation of the spiked E2(3S) in the post-treatment system.

Role of UASBs in River Water Quality Conservation in India

NASA Astrophysics Data System (ADS)

Gali, Veeresh; Thakur, Manisha; Gupta, Ashok Kumar; Ganguly, Rajiv

2018-03-01

Appropriate low-cost treatment technologies are a prerequisite for sound management of natural water resources against pollution in developing countries. Among the existing technologies available, UASB is found to be economically viable for India when considering all factors including operation and maintenance cost and treatment efficiency. However, this technology suffers setbacks in meeting the effluent guidelines prescribed by the government of India. Post treatment is supplemental to this process to meet the effluent standards in terms of removal of organic matter, suspended solids, pathogens and nutrients. Recent stringent effluent guidelines notified by the Ministry of Environment, Forests and Climate Change, Government of India has further reduced the limits of BOD by 3 times, COD and TSS by 5 times, NH4-N and total Nitrogen by 10 times as compared to the previous guidelines. Fecal Coliforms has been specified as <100MPN/100mL. In this paper, the present scenario of UASB based STPs and their role in river conservation is reviewed against the backdrop of stringent effluent guidelines. The minimum removal rates of BOD, COD and TSS in these plants are around 42 - 44% and the average removal rates are reported to be 66%, 61% and 65% respectively. The enhanced removal of BOD (97%), COD (98%) and TSS has been reported in STPs in conjunction with post treatment facilities such as facultative aerated lagoons, aeration tanks and polishing ponds.

A coupled system of half-nitritation and ANAMMOX for mature landfill leachate nitrogen removal.

PubMed

Li, Yun; Li, Jun; Zhao, Baihang; Wang, Xiujie; Zhang, Yanzhuo; Wei, Jia; Bian, Wei

2017-09-01

A coupled system of membrane bioreactor-nitritation (MBR-nitritation) and up-flow anaerobic sludge blanket-anaerobic ammonium oxidation (UASB-ANAMMOX) was employed to treat mature landfill leachate containing high ammonia nitrogen and low C/N. MBR-nitritation was successfully realized for undiluted mature landfill leachate with initial concentrations of 900-1500 mg/L [Formula: see text] and 2000-4000 mg/L chemical oxygen demand. The effluent [Formula: see text] concentration and the [Formula: see text] accumulation efficiency were 889 mg/L and 97% at 125 d, respectively. Half-nitritation was quickly realized by adjustment of hydraulic retention time and dissolved oxygen (DO), and a low DO control strategy could allow long-term stable operation. The UASB-ANAMMOX system showed high effective nitrogen removal at a low concentration of mature landfill leachate. The nitrogen removal efficiency was inhibited at excessive influent substrate concentration and the nitrogen removal efficiency of the system decreased as the concentration of mature landfill leachate increased. The MBR-nitritation and UASB-ANAMMOX processes were coupled for mature landfill leachate treatment and together resulted in high effective nitrogen removal. The effluent average total nitrogen concentration and removal efficiency values were 176 mg/L and 83%, respectively. However, the average nitrogen removal load decreased from 2.16 to 0.77 g/(L d) at higher concentrations of mature landfill leachate.

Assessment of bacterial and archaeal community structure in Swine wastewater treatment processes.

PubMed

Da Silva, Marcio Luis Busi; Cantão, Mauricio Egídio; Mezzari, Melissa Paola; Ma, Jie; Nossa, Carlos Wolfgang

2015-07-01

Microbial communities from two field-scale swine wastewater treatment plants (WWTPs) were assessed by pyrosequencing analyses of bacterial and archaeal 16S ribosomal DNA (rDNA) fragments. Effluent samples from secondary (anaerobic covered lagoons and upflow anaerobic sludge blanket [UASB]) and tertiary treatment systems (open-pond natural attenuation lagoon and air-sparged nitrification-denitrification tank followed by alkaline phosphorus precipitation process) were analyzed. A total of 56,807 and 48,859 high-quality reads were obtained from bacterial and archaeal libraries, respectively. Dominant bacterial communities were associated with the phylum Firmicutes, Bacteroidetes, Proteobacteria, or Actinobacteria. Bacteria and archaea diversity were highest in UASB effluent sample. Escherichia, Lactobacillus, Bacteroides, and/or Prevotella were used as indicators of putative pathogen reduction throughout the WWTPs. Satisfactory pathogen reduction was observed after the open-pond natural attenuation lagoon but not after the air-sparged nitrification/denitrification followed by alkaline phosphorus precipitation treatment processes. Among the archaeal communities, 80% of the reads was related to hydrogeno-trophic methanogens Methanospirillum. Enrichment of hydrogenotrophic methanogens detected in effluent samples from the anaerobic covered lagoons and UASB suggested that CO2 reduction with H2 was the dominant methanogenic pathway in these systems. Overall, the results served to improve our current understanding of major microbial communities' changes downgradient from the pen and throughout swine WWTP as a result of different treatment processes.

Selection criteria for wastewater treatment technologies to protect drinking water.

PubMed

von Sperling, M

2000-01-01

The protection of water bodies used as sources for drinking water is intimately linked to the adoption of adequate technologies for the treatment of the wastewater generated in the catchment area. The paper presents a general overview of the main technologies used for the treatment of domestic sewage, with a special emphasis on developing countries, and focussing on the main parameters of interest, such as BOD, coliforms and nutrients. A series of tables, figures and charts that can be used for the preliminary selection of treatment technologies is presented. The systems analysed are: stabilisation ponds, activated sludge, trickling filters, anaerobic systems and land disposal. Within each system, the main process variants are covered. Two summary tables are presented, one for quantitative analysis, including easily usable information based on per capita values (US$/cap, Watts/cap, m2 area/cap, m3 sludge/cap), and another for a qualitative comparison among the technologies, based on a one-to-five-star scoring system. The recent trend in tropical countries in the use of UASB (Upflow Anaerobic Sludge Blanket) reactors is also discussed.

Ectopic Bone Matrix Mineralization: Unveiling the Osteoinductive Nature of Crab Cuticle

NASA Astrophysics Data System (ADS)

Omokanwaye, Tiffany Suella

Engineered nanomaterials are increasingly used in a variety of industrial processes and consumer products. Numerous studies have reported toxicity of different NPs during the last years. Thus, there are growing concerns about the potential impacts to the health and environment of engineered nanoparticles (NPs). However, some methodological problems complicate the interpretation of nanotoxicity studies. On the one hand, some NPs have shown to interfere with classical toxicity assays based on colorimetric or fluorescent measurements. On the other hand, most NPs tend to aggregate in media used in toxicity tests, which complicates the interpretation of the toxicity results. The first objective of this dissertation was to evaluate a novel impedance-based and label-free real time cell analyzer (RTCA) as a high throughput method for screening the cytotoxicity of nanoparticles and to validate the RTCA results using a conventional cytotoxicity test (MTT). Several inorganic NPs were tested for potential cytotoxicity to human bronchial epithelial cells (16HBE14o-). In general, there was a good correlation in cytotoxicity measurements between the two methods. Moreover, none of the NPs tested showed interference with the impedance measurements performed by the RTCA system. The results demonstrate the potential and validity of the impedance-based RTCA technique to rapidly screen for NP toxicity. The second objective of this dissertation was to assess the toxicity of different inorganic NPs to the eukaryotic cell model Saccharomyces cerevisiae, and to test the influence of NP aggregation state in their toxicity. Nanotoxicity was assessed by monitoring oxygen consumption in batch cultures and by analysis of cell membrane integrity. Mn2O3 NPs showed the highest inhibition of O2 consumption and cell membrane damage, while the other NPs caused low or no toxicity to the yeast. Most NPs showed high tendency to aggregate in the assay medium, so a non-toxic dispersant was used to improve NP stability. In contrast to aggregated CeO2 NPs, dispersed CeO 2 NPs showed toxicity to the yeast. However, dispersant supplementation decreased the inhibition caused by Mn2O3 NPs at low concentrations, which could indicate that dispersant association with the particles may have an impact on the interaction between the NPs and the cells. The proven toxicity of some NPs raises concerns about their environmental fate. Municipal and industrial wastewaters are considered primary sources of NPs to the environment. However, information on the behavior and impact of NPs on wastewater treatment processes is very limited. A third objective of this dissertation was to evaluate the fate and long-term effect of ZnO and CuO NPs during wastewater treatment in high-rate anaerobic bioreactors. Laboratory-scale upflow anaerobic sludge blanket (UASB) reactors were fed with synthetic wastewater containing NPs for extended periods of time (> 90 d). Extensive removal (62-82%) of ZnO and CuO NPs was observed during wastewater treatment in the UASB reactors. Scanning electron microscopy and chemical analysis confirmed that NPs were associated with the anaerobic sludge. While short-term exposure to low levels of ZnO and CuO NPs only caused minor inhibition to methanogenesis, extended exposure to NPs accumulated in the sludge bed led to a gradual and partial inhibitory response in the reactors. The inhibitory effect was also evident in the decline in the acetoclastic methanogenic activity of the biomass.

[Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

PubMed

Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

2015-09-01

The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

Control of dissolved CH4 in a municipal UASB reactor effluent by means of a desorption - Biofiltration arrangement.

PubMed

Huete, A; de Los Cobos-Vasconcelos, D; Gómez-Borraz, T; Morgan-Sagastume, J M; Noyola, A

2018-06-15

The direct anaerobic treatment of municipal wastewater represents an adapted technology to the conditions of developing countries. In order to get an increased acceptance of this technology, a proper control of dissolved methane in the anaerobic effluents should be considered, as methane is a potent greenhouse gas. In this study, a pilot-scale system was operated for 168 days to recover dissolved methane from an effluent of an upflow anaerobic sludge blanket reactor and then oxidize it in a compost biofilter. The system operated at a constant air (0.9 m 3 /h ±0.09) and two air-to anaerobic effluent ratio (1:1 and 1:2). In both conditions (CH 4 concentration of 2.7 ± 0.87 and 4.3% ± 1.14, respectively) the desorption column recovered 99% of the dissolved CH 4 and approximately 30% ± 8.5 of H 2 S, whose desorption was limited due to the high pH (>8) of the effluent. The biofilter removed 70% ± 8 of the average CH 4 load (60 gCH 4 /m 3 h ± 13) and 100% of the H 2 S load at an empty bed retention time of 23 min. The average temperature inside the biofilter was 42 ± 9 °C due to the CH 4 oxidation reaction, indicating that temperature and moisture control is particularly important for CH 4 removal in compost biofilters. The system may achieve a 54% reduction of greenhouse gas emissions from dissolved CH 4 in this particular case. Copyright © 2017 Elsevier Ltd. All rights reserved.

10 CFR 51.107 - Public hearings in proceedings for issuance of combined licenses; limited work authorizations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the issuance of a combined license for a nuclear power reactor under part 52 of this chapter, the... or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) If a combined license... authorization should be issued as proposed by the Director of New Reactors or the Director of Nuclear Reactor...

10 CFR 51.107 - Public hearings in proceedings for issuance of combined licenses; limited work authorizations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the issuance of a combined license for a nuclear power reactor under part 52 of this chapter, the... or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) If a combined license... authorization should be issued as proposed by the Director of New Reactors or the Director of Nuclear Reactor...

10 CFR 51.107 - Public hearings in proceedings for issuance of combined licenses; limited work authorizations.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the issuance of a combined license for a nuclear power reactor under part 52 of this chapter, the... or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) If a combined license... authorization should be issued as proposed by the Director of New Reactors or the Director of Nuclear Reactor...

10 CFR 51.107 - Public hearings in proceedings for issuance of combined licenses; limited work authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the issuance of a combined license for a nuclear power reactor under part 52 of this chapter, the... or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) If a combined license... authorization should be issued as proposed by the Director of New Reactors or the Director of Nuclear Reactor...

10 CFR 51.107 - Public hearings in proceedings for issuance of combined licenses; limited work authorizations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the issuance of a combined license for a nuclear power reactor under part 52 of this chapter, the... or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) If a combined license... authorization should be issued as proposed by the Director of New Reactors or the Director of Nuclear Reactor...

Use of life cycle assessment to evaluate environmental impacts associated with the management of sludge and biogas.

PubMed

do Amaral, Karina Cubas; Aisse, Miguel Mansur; Possetti, Gustavo Rafael Collere; Prado, Marcelo Real

2018-05-01

Upflow anaerobic sludge blanket (UASB) reactors used in sewage treatment generate two by-products that can be reused: sludge and biogas. At the present time in Brazil, most of this resulting sludge is disposed of in sanitary landfills, while biogas is commonly burned off in low-efficiency flares. The aim of the present study was to use life cycle assessment to evaluate the environmental impacts from four different treatment and final destination scenarios for the main by-products of wastewater treatment plants. The baseline scenario, in which the sludge was sanitized using prolonged alkaline stabilization and, subsequently, directed toward agricultural applications and the biogas destroyed in open burners, had the most impact in the categories of global warming, terrestrial ecotoxicity, and human non-carcinogenic toxicity. The scenario in which heat resulting from biogas combustion is used to dry the sludge showed significant improvements over the baseline scenario in all the evaluated impact categories. The recovery of heat from biogas combustion decreased significantly the environmental impact associated with global warming. The combustion of dried sludge is another alternative to improve the sludge management. Despite the reduction of sludge volume to ash, there are environmental impacts inherent to ozone formation and terrestrial acidification.

Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

PubMed

Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

2012-01-01

Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

Diversity and degradation mechanism of an anaerobic bacterial community treating phenolic wastewater with sulfate as an electron acceptor.

PubMed

Guo, X J; Lu, Z Y; Wang, P; Li, H; Huang, Z Z; Lin, K F; Liu, Y D

2015-10-01

Petrochemical wastewater often contains high concentrations of phenol and sulfate that must be properly treated to meet discharge standards. This study acclimated anaerobic-activated sludge to treat saline phenolic wastewater with sulfate reduction and clarified the diversity and degradation mechanism of the microbial community. The active sludge in an upflow anaerobic sludge blanket (UASB) reactor could remove 90 % of phenol and maintain the effluent concentration of SO4 (2-) below 400 mg/L. Cloning and sequencing showed that Clostridium spp. and Desulfotomaculum spp. were major phenol-degrading bacteria. Phenol was probably degraded through the carboxylation pathway and sulfate reduction catalyzed by adenosine-5'-phosphosulfate (APS) reductase and dissimilatory sulfite reductase (DSR). A real-time polymerase chain reaction (RT-PCR) showed that as phenol concentration increased, the quantities of 16S rRNA gene, dsrB, and mcrA in the sludge all decreased. The relative abundance of dsrB dropped to 12.46 %, while that of mcrA increased to 56.18 %. The change in the electron flow ratio suggested that the chemical oxygen demand (COD) was removed mainly by sulfate-reducing bacteria under a phenol concentration of 420 mg/L, whereas it was removed mainly by methanogens above 630 mg/L.

Significance of dissolved methane in effluents of anaerobically ...

EPA Pesticide Factsheets

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

Performance of UASB septic tank for treatment of concentrated black water within DESAR concept.

PubMed

Kujawa-Roeleveld, K; Fernandes, T; Wiryawan, Y; Tawfik, A; Visser, M; Zeeman, G

2005-01-01

Separation of wastewater streams produced in households according to their origin, degree of pollution and affinity to a specific treatment constitutes a starting point in the DESAR concept (decentralised sanitation and reuse). Concentrated black water and kitchen waste carry the highest load of organic matter and nutrients from all waste(water)streams generated from different human activities. Anaerobic digestion of concentrated black water is a core technology in the DESAR concept. The applicability of the UASB septic tank for treatment of concentrated black water was investigated under two different temperatures, 15 and 25 degrees C. The removal of total COD was dependent on the operational temperature and attained 61 and 74% respectively. A high removal of the suspended COD of 88 and 94% respectively was measured. Effluent nutrients were mainly in the soluble form. Precipitation of phosphate was observed. Effective sludge/water separation, long HRT and higher operational temperature contributed to a reduction of E. coli. Based on standards there is little risk of contamination with heavy metals when treated effluent is to be applied in agriculture as fertiliser.

Evaluation of methanogenic treatment of TMAH (tetra-methyl ammonium hydroxide) in a full-scale TFT-LCD wastewater treatment process.

PubMed

Hu, T H; Whang, L M; Lei, C N; Chen, C F; Chiang, T Y; Lin, L B; Chen, H W; Liu, P W G; Cheng, S S

2010-01-01

This study evaluated TMAH biodegradation under methanogenic conditions. Under methanogenic conditions, a sludge from a full-scale UASB treating TFT-LCD wastewater was able to degrade 2,000 mg/L of TMAH within 10 h and attained a specific degradation rate of 19.2 mgTMAH/gVSS-h. Furthermore, several chemicals including some surfactants, DMSO, and sulfate were examined for their potential inhibitory effects on TMAH biodegradation under methanogenic conditions. The results indicated that surfactant S1 (up to 2%) and DMSO (up to 1,000 mg/L) presented negligible inhibitory effects on TMAH degradation, while surfactant S2 (0.2-1%) might inhibit methanogenic reaction without any TMAH degradation for 3-5 h. At sulfate concentrations higher than 300 mg/L, a complete inhibition of methanogenic reaction and TMAH biodegradation was observed. Results from cloning and sequencing of archaeal 16S rRNA gene fragments showed that Methanosarcina barkeri and Methanosarcina mazei were the dominant methanogens in the UASB treating TMAH-containing TFT-LCD wastewater.

Technical potential of microalgal bacterial floc raceway ponds treating food-industry effluents while producing microalgal bacterial biomass: An outdoor pilot-scale study.

PubMed

Van Den Hende, Sofie; Beelen, Veerle; Julien, Lucie; Lefoulon, Alexandra; Vanhoucke, Thomas; Coolsaet, Carlos; Sonnenholzner, Stanislaus; Vervaeren, Han; Rousseau, Diederik P L

2016-10-01

To replace costly mechanical aeration by photosynthetical aeration, upflow anaerobic sludge blanket (UASB) effluent of food-industry was treated in an outdoor MaB-floc raceway pond. Photosynthetic aeration was sufficient for nitrification, but the raceway effluent quality was below current discharge limits, despite the high hydraulic retention time (HRT) of 35days. Hereafter, conventional activated sludge (CAS) effluent of food-industry was treated in this pond to recover phosphorus. The two-day HRT results in a more realistic pond area, but the phosphorus removal efficiency was low (20%). High biomass productivities were obtained, i.e. 31.3 and 24.9ton total suspended solids hapond(-1)year(-1) for UASB and CAS effluent, respectively. Bioflocculation enabled successful harvesting of CAS effluent-fed MaB-flocs by settling and filtering at 150-250μm to 22.7% total solids. To conclude, MaB-floc raceway ponds cannot be recommended as the sole treatment for these food-industry effluents, but huge potential lies in added-value biomass production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Symbiotic relationship analysis of predominant bacteria in a lab-scale anammox UASB bioreactor.

PubMed

Wang, Yujia; Hu, Xiaomin; Jiang, Binhui; Song, Zhenhui; Ma, Yongguang

2016-04-01

In order to provide the comprehensive insight into the key microbial groups in anaerobic ammonium oxidation (anammox) process, high-throughput sequencing analysis has been used for the investigation of the bacterial communities of a lab-scale upflow anaerobic sludge bed (UASB) anammox bioreactor. Results revealed that 109 operational taxonomic units (OTUs; out of 14,820 reads) were identified and a domination of anammox bacteria of Candidatus Kuenenia stuttgartiensis (OTU474, 35.42 %), along with heterotrophs of Limnobacter sp. MED105 (OTU951, 14.98 %), Anerolinea thermophila UNI-1 (OTU465 and OTU833, 6.60 and 3.93 %), Azoarcus sp. B72 (OTU26, 9.47 %), and Ignavibacterium sp. JCM 16511 (OTU459, 8.33 %) were detected. Metabolic pathway analysis showed that Candidatus K. stuttgartiensis encountered gene defect in synthesizing a series of metabolic cofactors for growth, implying that K. stuttgartiensis is auxotrophic. Coincidentally, the other dominant species severally showed complete metabolic pathways with full set gene encoding to corresponding cofactors presented in the surrounding environment. Furthermore, it was likely that the survival of heterotrophs in the autotrophic system indicates the existence of a symbiotic and mutual relationship in anammox system.

Further contributions to the understanding of nitrogen removal in waste stabilization ponds.

PubMed

Bastos, R K X; Rios, E N; Sánchez, I A

2018-06-01

A set of experiments were conducted in Brazil in a pilot-scale waste stabilization pond (WSP) system (a four-maturation-pond series) treating an upflow anaerobic sludge blanket (UASB) reactor effluent. Over a year and a half the pond series was monitored under two flow rate conditions, hence also different hydraulic retention times and surface loading rates. On-site and laboratory trials were carried out to assess: (i) ammonia losses by volatilization using acrylic capture chambers placed at the surface of the ponds; (ii) organic nitrogen sedimentation rates using metal buckets placed at the bottom of the ponds for collecting settled particulate matter; (iii) nitrogen removal by algal uptake based on the nitrogen content of the suspended particulate matter in samples from the ponds' water column. In addition, nitrification and denitrification rates were measured in laboratory-based experiments using pond water and sediment samples. The pond system achieved high nitrogen removal (69% total nitrogen and 92% ammonia removal). The average total nitrogen removal rates varied from 10,098 to 3,849 g N/ha·d in the first and the last ponds, respectively, with the following fractions associated with the various removal pathways: (i) 23.5-45.6% sedimentation of organic nitrogen; (ii) 13.1-27.8% algal uptake; (iii) 1.2-3.1% ammonia volatilization; and (iv) 0.15-0.34% nitrification-denitrification.

Off-design performance of a chemical looping combustion (CLC) combined cycle: effects of ambient temperature

NASA Astrophysics Data System (ADS)

Chi, Jinling; Wang, Bo; Zhang, Shijie; Xiao, Yunhan

2010-02-01

The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion (CLC) combined cycle. A sensitivity analysis of the CLC reactor system was conducted, which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor. For the ambient temperature variation, three off-design control strategies have been assumed and compared: 1) without any Inlet Guide Vane (IGV) control, 2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature, aside from fuel flow rate adjusting. Results indicate that, compared with the conventional combined cycle, due to the requirement of pressure balance at outlet of the two CLC reactors, CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted. For the first control strategy, temperatures of the two CLC reactors both rise obviously as ambient temperature increases. IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point. Compare with the second strategy, the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.

78 FR 28896 - Design Limits and Loading Combinations for Metal Primary Reactor Containment System Components

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-16

... NUCLEAR REGULATORY COMMISSION [NRC-2013-0095] Design Limits and Loading Combinations for Metal... Regulatory Guide (RG) 1.57, ``Design Limits and Loading Combinations for Metal Primary Reactor Containment... the NRC staff considers acceptable for design limits and loading combinations for metal primary...

75 FR 36126 - Office of New Reactors; Proposed Revision to Standard Review Plan Section 13.6.1, Revision 1 on...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-24

... NUCLEAR REGULATORY COMMISSION [NRC-2010-0228] Office of New Reactors; Proposed Revision to Standard Review Plan Section 13.6.1, Revision 1 on Physical Security--Combined License and Operating...), Section 13.6.1 on ``Physical Security--Combined License and Operating Reactors,'' (Agencywide Documents...

The combined hybrid system: A symbiotic thermal reactor/fast reactor system for power generation and radioactive waste toxicity reduction

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

Hollaway, W.R.

1991-08-01

If there is to be a next generation of nuclear power in the United States, then the four fundamental obstacles confronting nuclear power technology must be overcome: safety, cost, waste management, and proliferation resistance. The Combined Hybrid System (CHS) is proposed as a possible solution to the problems preventing a vigorous resurgence of nuclear power. The CHS combines Thermal Reactors (for operability, safety, and cost) and Integral Fast Reactors (for waste treatment and actinide burning) in a symbiotic large scale system. The CHS addresses the safety and cost issues through the use of advanced reactor designs, the waste management issuemore » through the use of actinide burning, and the proliferation resistance issue through the use of an integral fuel cycle with co-located components. There are nine major components in the Combined Hybrid System linked by nineteen nuclear material mass flow streams. A computer code, CHASM, is used to analyze the mass flow rates CHS, and the reactor support ratio (the ratio of thermal/fast reactors), IFR of the system. The primary advantages of the CHS are its essentially actinide-free high-level radioactive waste, plus improved reactor safety, uranium utilization, and widening of the option base. The primary disadvantages of the CHS are the large capacity of IFRs required (approximately one MW{sub e} IFR capacity for every three MW{sub e} Thermal Reactor) and the novel radioactive waste streams produced by the CHS. The capability of the IFR to burn pure transuranic fuel, a primary assumption of this study, has yet to be proven. The Combined Hybrid System represents an attractive option for future nuclear power development; that disposal of the essentially actinide-free radioactive waste produced by the CHS provides an excellent alternative to the disposal of intact actinide-bearing Light Water Reactor spent fuel (reducing the toxicity based lifetime of the waste from roughly 360,000 years to about 510 years).« less

10 CFR 2.621 - Acceptance and docketing of application for early review of site suitability issues in a combined...

Code of Federal Regulations, 2014 CFR

2014-01-01

... Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, will inform the... Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, will accept for... New Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, that they...

10 CFR 2.621 - Acceptance and docketing of application for early review of site suitability issues in a combined...

Code of Federal Regulations, 2013 CFR

2013-01-01

... Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, will inform the... Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, will accept for... New Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, that they...

10 CFR Appendix N to Part 52 - Standardization of Nuclear Power Plant Designs: Combined Licenses To Construct and Operate...

Code of Federal Regulations, 2011 CFR

2011-01-01

... Licenses To Construct and Operate Nuclear Power Reactors of Identical Design at Multiple Sites N Appendix N... Designs: Combined Licenses To Construct and Operate Nuclear Power Reactors of Identical Design at Multiple... construct and operate nuclear power reactors of identical design (“common design”) to be located at multiple...

10 CFR 50.30 - Filing of application; oath or affirmation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Reactor Regulation, Director, Office of New Reactors, or Director, Office of Nuclear Material Safety and... Director, Office of New Reactors, or the Director, Office of Nuclear Reactor Regulation, or the Director..., operating license, early site permit, combined license, or manufacturing license for a nuclear power reactor...

10 CFR 50.30 - Filing of application; oath or affirmation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Reactor Regulation, Director, Office of New Reactors, or Director, Office of Nuclear Material Safety and... Director, Office of New Reactors, or the Director, Office of Nuclear Reactor Regulation, or the Director..., operating license, early site permit, combined license, or manufacturing license for a nuclear power reactor...

10 CFR 50.30 - Filing of application; oath or affirmation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Reactor Regulation, Director, Office of New Reactors, or Director, Office of Nuclear Material Safety and... Director, Office of New Reactors, or the Director, Office of Nuclear Reactor Regulation, or the Director..., operating license, early site permit, combined license, or manufacturing license for a nuclear power reactor...

10 CFR 50.30 - Filing of application; oath or affirmation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Reactor Regulation, Director, Office of New Reactors, or Director, Office of Nuclear Material Safety and... Director, Office of New Reactors, or the Director, Office of Nuclear Reactor Regulation, or the Director..., operating license, early site permit, combined license, or manufacturing license for a nuclear power reactor...

METHOD OF OPERATING NUCLEAR REACTORS

DOEpatents

Untermyer, S.

1958-10-14

A method is presented for obtaining enhanced utilization of natural uranium in heavy water moderated nuclear reactors by charging the reactor with an equal number of fuel elements formed of natural uranium and of fuel elements formed of uranium depleted in U/sup 235/ to the extent that the combination will just support a chain reaction. The reactor is operated until the rate of burnup of plutonium equals its rate of production, the fuel elements are processed to recover plutonium, the depleted uranium is discarded, and the remaining uranium is formed into fuel elements. These fuel elements are charged into a reactor along with an equal number of fuel elements formed of uranium depleted in U/sup 235/ to the extent that the combination will just support a chain reaction, and reuse of the uranium is continued as aforesaid until it wlll no longer support a chain reaction when combined with an equal quantity of natural uranium.

Fact-finding survey of actual garbage discharged from dormitory and its biological anaerobic-aerobic treatment.

PubMed

Imai, T; Ukita, M; Sekine, M; Fukagawa, M; Nakanishi, H

2000-01-01

The objective of this study is to find a possibility of complete treatment of garbage and resource recovery (production of methane from available utility of carbon resource in garbage) by biological treatment process. As the first step, a fact-finding survey of actual garbage discharged from the dormitory of the Ube National College of Technology (equivalent to 300 population) was carried out. Second, the combined biological anaerobic-aerobic treatment, i.e. combination of upflow anaerobic sludge blanket (UASB) process and aerobic membrane bioreactor (AMB) process, was applied to the garbage treatment. The applicability and efficiency of this system were investigated in this study. The survey results showed that the composition and quantity of garbage from a student dormitory changed slightly during a week due to the change of the menu, however, they remained almost unchanged during the entire experimental period. The experimental results showed high biodegradability of the garbage, and demonstrated its suitability for methane production. The soluble nitrogen removal was high: over 97%. No excess sludge was wasted from the system. A high treatment efficiency of simultaneous organic carbon and nitrogen was obtained. The possibility of complete treatment of garbage with this process has been positively demonstrated by this study.

10 CFR 100.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... COMMISSION (CONTINUED) REACTOR SITE CRITERIA § 100.3 Definitions. As used in this part: Combined license... power facilities. Exclusion area means that area surrounding the reactor, in which the reactor licensee.... Activities unrelated to operation of the reactor may be permitted in an exclusion area under appropriate...

10 CFR 100.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... COMMISSION (CONTINUED) REACTOR SITE CRITERIA § 100.3 Definitions. As used in this part: Combined license... power facilities. Exclusion area means that area surrounding the reactor, in which the reactor licensee.... Activities unrelated to operation of the reactor may be permitted in an exclusion area under appropriate...

Propellant actuated nuclear reactor steam depressurization valve

DOEpatents

Ehrke, Alan C.; Knepp, John B.; Skoda, George I.

1992-01-01

A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

Porous stabilized beds, methods of manufacture thereof and articles comprising the same

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

Klausner, James F.; Mei, Renwei; Momen, Ayyoub Mehdizadeh

Disclosed herein is a method comprising disposing a first particle in a reactor; the first particle being a magnetic particle or a particle that can be influenced by a magnetic field, an electric field or a combination of an electrical field and a magnetic field; fluidizing the first particle in the reactor; applying a uniform magnetic field, a uniform electrical field or a combination of a uniform magnetic field and a uniform electrical field to the reactor; elevating the temperature of the reactor; and fusing the first particles to form a monolithic solid.

10 CFR 2.621 - Acceptance and docketing of application for early review of site suitability issues in a combined...

Code of Federal Regulations, 2012 CFR

2012-01-01

... Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation, as...) The Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation... of Nuclear Reactor Regulation, as appropriate, that they are complete. (c) If part one of the...

Methanation assembly using multiple reactors

DOEpatents

Jahnke, Fred C.; Parab, Sanjay C.

2007-07-24

A methanation assembly for use with a water supply and a gas supply containing gas to be methanated in which a reactor assembly has a plurality of methanation reactors each for methanating gas input to the assembly and a gas delivery and cooling assembly adapted to deliver gas from the gas supply to each of said methanation reactors and to combine water from the water supply with the output of each methanation reactor being conveyed to a next methanation reactor and carry the mixture to such next methanation reactor.

Function of university reactors in operator licensing training for nuclear utilities

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

Wicks, F.

1985-11-01

The director of the Division of the US Nuclear Regulatory Commission in generic letter 84-10, dated April 26, 1984, spoke the requirement that applicants for senior reactor operator licenses for power reactors shall have performed then reactor startups. Simulator startups were not acknowledged. Startups performed on a university reactor are acceptable. The content and results of a five-day program combining instruction and experiments with the Rensselaer reactor are summarized.

Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow conditions

NASA Astrophysics Data System (ADS)

Ren, Lijiao; Ahn, Yongtae; Hou, Huijie; Zhang, Fang; Logan, Bruce E.

2014-07-01

Power production of four hydraulically connected microbial fuel cells (MFCs) was compared with the reactors operated using individual electrical circuits (individual), and when four anodes were wired together and connected to four cathodes all wired together (combined), in fed-batch or continuous flow conditions. Power production under these different conditions could not be made based on a single resistance, but instead required polarization tests to assess individual performance relative to the combined MFCs. Based on the power curves, power produced by the combined MFCs (2.12 ± 0.03 mW, 200 Ω) was the same as the summed power (2.13 mW, 50 Ω) produced by the four individual reactors in fed-batch mode. With continuous flow through the four MFCs, the maximum power (0.59 ± 0.01 mW) produced by the combined MFCs was slightly lower than the summed maximum power of the four individual reactors (0.68 ± 0.02 mW). There was a small parasitic current flow from adjacent anodes and cathodes, but overall performance was relatively unaffected. These findings demonstrate that optimal power production by reactors hydraulically and electrically connected can be predicted from performance by individual reactors.

75 FR 30451 - Duke Energy Carolinas, LLC; Duke Energy Carolinas, LLC; William States Lee III Combined License...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... Energy Carolinas, LLC; William States Lee III Combined License Application; Notice of Intent To Conduct a... environmental review of the William States Lee III Nuclear Station, Units 1 and 2 combined licenses application...-licensing/col/lee.html '' to `` http://www.nrc.gov/reactors/new-reactors/col/lee.html ''. Dated at Rockville...

Jet pump-drive system for heat removal

NASA Technical Reports Server (NTRS)

French, James R. (Inventor)

1987-01-01

The invention does away with the necessity of moving parts such as a check valve in a nuclear reactor cooling system. Instead, a jet pump, in combination with a TEMP, is employed to assure safe cooling of a nuclear reactor after shutdown. A main flow exists for a reactor coolant. A point of withdrawal is provided for a secondary flow. A TEMP, responsive to the heat from said coolant in the secondary flow path, automatically pumps said withdrawn coolant to a higher pressure and thus higher velocity compared to the main flow. The high velocity coolant is applied as a driver flow for the jet pump which has a main flow chamber located in the main flow circulation pump. Upon nuclear shutdown and loss of power for the main reactor pumping system, the TEMP/jet pump combination continues to boost the coolant flow in the direction it is already circulating. During the decay time for the nuclear reactor, the jet pump keeps running until the coolant temperature drops to a lower and safe temperature where the heat is no longer a problem. At this lower temperature, the TEMP/jet pump combination ceases its circulation boosting operation. When the nuclear reactor is restarted and the coolant again exceeds the lower temperature setting, the TEMP/jet pump automatically resumes operation. The TEMP/jet pump combination is thus automatic, self-regulating and provides an emergency pumping system free of moving parts.

Fast formation of aerobic granules by combining strong hydraulic selection pressure with overstressed organic loading rate.

PubMed

Liu, Yong-Qiang; Tay, Joo-Hwa

2015-09-01

The combined strong hydraulic selection pressure (HSP) with overstressed organic loading rate (OLR) as a fast granulation strategy was used to enhance aerobic granulation. To investigate the wide applicability of this strategy to different scenarios and its relevant mechanism, different settling times, different inoculums, different exchange ratios, different reactor configurations, and different shear force were used in this study. It was found that clear granules were formed within 24 h and steady state reached within three days when the fast granulation strategy was used in a lab-scale reactor seeded with well settled activated sludge (Reactor 2). However, granules appeared after 2-week operation and reached steady state after one month at the traditional step-wise decreased settling time from 20 to 2 min with OLR of 6 g COD/L·d (Reactor 1). With the fast granulation strategy, granules appeared within 24 h even with bulking sludge as seed to start up Reactor 3, but 6-day lag phase was observed compared with Reactor 2. Both Reactor 2 and Reactor 3 experienced sigmoidal growth curve in terms of biomass accumulation and granule size increase after granulation. In addition, the reproducible results in pilot-scale reactors (Reactor 5 and Reactor 6) with diameter of 20 cm and height/diameter ratio (H/D) of 4 further proved that reactor configuration and fluid flow pattern had no effect on the aerobic granulation when the fast granulation strategy was employed, but biomass accumulation experienced a short lag phase too in Reactor 5 and Reactor 6. Although overstressed OLR was favorable for fast granulation, it also led to the fluffy granules after around two-week operation. However, the stable 6-month operation of Reactor 3 demonstrated that the rapidly formed granules were able to maintain long-term stability by reducing OLR from 12 g COD/L·d to 6 g COD/L·d. A mechanism of fast granulation with the strategy of combined strong HSP and OLR was proposed to explain results and guide the operation with this fast strategy. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-rate treatment of molasses wastewater by combination of an acidification reactor and a USSB reactor.

PubMed

Onodera, Takashi; Sase, Shinya; Choeisai, Pairaya; Yoochatchaval, Wilasinee; Sumino, Haruhiko; Yamaguchi, Takashi; Ebie, Yoshitaka; Xu, Kaiqin; Tomioka, Noriko; Syutsubo, Kazuaki

2011-01-01

A combination of an acidification reactor and an up-flow staged sludge bed (USSB) reactor was applied for treatment of molasses wastewater containing a large amount of organic compounds and sulfate. The USSB reactor had three gas-solid separators (GSS) along the height of the reactor. The combined system was continuously operated at mesophilic temperature over 400 days. In the acidification reactor, acid formation and sulfate reduction were effectively carried out. The sugars contained in the influent wastewater were mostly acidified into acetate, propionate, and n-butyrate. In addition, 10-30% of influent sulfur was removed from the acidification reactor by means of sulfate reduction followed by stripping of hydrogen sulfide. The USSB achieved a high organic loading rate (OLR) of 30 kgCOD m(-3) day(-1) with 82% COD removal. Vigorous biogas production was observed at a rate of 15 Nm(3) biogas m(-3) reactor day(-1). The produced biogas, including hydrogen sulfide, was removed from the wastewater mostly via the GSS. The GSS provided a moderate superficial biogas flux and low sulfide concentration in the sludge bed, resulting in the prevention of sludge washout and sulfide inhibition of methanogens. By advantages of this feature, the USSB may have been responsible for achieving sufficient retention (approximately 60 gVSS L(-1)) of the granular sludge with high methanogenic activity (0.88 gCOD gVSS(-1) day(-1) for acetate and as high as 2.6 gCOD gVSS(-1) day(-1) for H(2)/CO(2)). Analysis of the microbial community revealed that sugar-degrading acid-forming bacteria proliferated in the sludge of the USSB as well as the acidification reactor at high OLR conditions.

Application of real-time PCR to determination of combined effect of antibiotics on Bacteria, Methanogenic Archaea, Archaea in anaerobic sequencing batch reactors.

PubMed

Aydin, Sevcan; Ince, Bahar; Ince, Orhan

2015-06-01

This study evaluated the long-term effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotic combinations on the microbial community and examined the ways in which these antimicrobials impact the performance of anaerobic reactors. Quantitative real-time PCR was used to determine the effect that different antibiotic combinations had on the total and active Bacteria, Archae and Methanogenic Archae. Three primer sets that targeted metabolic genes encoding formylterahydrofolate synthetase, methyl-coenzyme M reductase and acetyl-coA synthetase were also used to determine the inhibition level on the mRNA expression of the homoacetogens, methanogens and specifically acetoclastic methanogens, respectively. These microorganisms play a vital role in the anaerobic degradation of organic waste and targeting these gene expressions offers operators or someone at a treatment plant the potential to control and the improve the anaerobic system. The results of the investigation revealed that acetogens have a competitive advantage over Archaea in the presence of ETS and ST combinations. Although the efficiency with which methane production takes place and the quantification of microbial populations in both the ETS and ST reactors decreased as antibiotic concentrations increased, the ETS batch reactor performed better than the ST batch reactor. According to the expression of genes results, the syntrophic interaction of acetogens and methanogens is critical to the performance of the ETS and ST reactors. Failure to maintain the stability of these microorganisms resulted in a decrease in the performance and stability of the anaerobic reactors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combined cooling and purification system for nuclear reactor spent fuel pit, refueling cavity, and refueling water storage tank

DOEpatents

Corletti, Michael M.; Lau, Louis K.; Schulz, Terry L.

1993-01-01

The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps.

Microbial community analysis in a combined anaerobic and aerobic digestion system for treatment of cellulosic ethanol production wastewater.

PubMed

Shan, Lili; Yu, Yanling; Zhu, Zebing; Zhao, Wei; Wang, Haiman; Ambuchi, John J; Feng, Yujie

2015-11-01

This study investigated the microbial diversity established in a combined system composed of a continuous stirred tank reactor (CSTR), expanded granular sludge bed (EGSB) reactor, and sequencing batch reactor (SBR) for treatment of cellulosic ethanol production wastewater. Excellent wastewater treatment performance was obtained in the combined system, which showed a high chemical oxygen demand removal efficiency of 95.8% and completely eliminated most complex organics revealed by gas chromatography-mass spectrometry (GC-MS). Denaturing gradient gel electrophoresis (DGGE) analysis revealed differences in the microbial community structures of the three reactors. Further identification of the microbial populations suggested that the presence of Lactobacillus and Prevotella in CSTR played an active role in the production of volatile fatty acids (VFAs). The most diverse microorganisms with analogous distribution patterns of different layers were observed in the EGSB reactor, and bacteria affiliated with Firmicutes, Synergistetes, and Thermotogae were associated with production of acetate and carbon dioxide/hydrogen, while all acetoclastic methanogens identified belonged to Methanosaetaceae. Overall, microorganisms associated with the ability to degrade cellulose, hemicellulose, and other biomass-derived organic carbons were observed in the combined system. The results presented herein will facilitate the development of an improved cellulosic ethanol production wastewater treatment system.

Combined cooling and purification system for nuclear reactor spent fuel pit, refueling cavity, and refueling water storage tank

DOEpatents

Corletti, M.M.; Lau, L.K.; Schulz, T.L.

1993-12-14

The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps. 1 figures.

Treatment of screened dairy manure by upflow anaerobic fixed bed reactors packed with waste tyre rubber and a combination of waste tyre rubber and zeolite: effect of the hydraulic retention time.

PubMed

Umaña, Oscar; Nikolaeva, Svetlana; Sánchez, Enrique; Borja, Rafael; Raposo, Francisco

2008-10-01

Two laboratory-scale anaerobic fixed bed reactors were evaluated while treating dairy manure at upflow mode and semicontinuous feeding. One reactor was packed with a combination of waste tyre rubber and zeolite (R1) while the other had only waste tyre rubber as a microorganism immobilization support (R2). Effluent quality improved when the hydraulic retention time (HRT) increased from 1.0 to 5.5 days. Higher COD, BOD5, total and volatile solids removal efficiencies were always achieved in the reactor R1. No clogging was observed during the operation period. Methane yield was also a function of the HRT and of the type of support used, and was 12.5% and 40% higher in reactor R1 than in R2 for HRTs of 5.5 and 1.0 days, respectively. The results obtained demonstrated that this type of reactor is capable of operating with dairy manure at a HRT 5 times lower than that used in a conventional reactor.

Bioelectrochemical enhancement of methane production from highly concentrated food waste in a combined anaerobic digester and microbial electrolysis cell.

PubMed

Park, Jungyu; Lee, Beom; Tian, Donjie; Jun, Hangbae

2018-01-01

A microbial electrolysis cell (MEC) is a promising technology for enhancing biogas production from an anaerobic digestion (AD) reactor. In this study, the effects of the MEC on the rate of methane production from food waste were examined by comparing an AD reactor with an AD reactor combined with a MEC (AD+MEC). The use of the MEC accelerated methane production and stabilization via rapid organic oxidation and rapid methanogenesis. Over the total experimental period, the methane production rate and stabilization time of the AD+MEC reactor were approximately 1.7 and 4.0 times faster than those of the AD reactor. Interestingly however, at the final steady state, the methane yields of both the reactors were similar to the theoretical maximum methane yield. Based on these results, the MEC did not increase the methane yield over the theoretical value, but accelerated methane production and stabilization by bioelectrochemical reactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photocatalytic mineralization of commercial herbicides in a pilot-scale solar CPC reactor: photoreactor modeling and reaction kinetics constants independent of radiation field.

PubMed

Colina-Márquez, Jose; Machuca-Martínez, Fiderman; Li Puma, Gianluca

2009-12-01

The six-flux absorption-scattering model (SFM) of the radiation field in the photoreactor, combined with reaction kinetics and fluid-dynamic models, has proved to be suitable to describe the degradation of water pollutants in heterogeneous photocatalytic reactors, combining simplicity and accuracy. In this study, the above approach was extended to model the photocatalytic mineralization of a commercial herbicides mixture (2,4-D, diuron, and ametryne used in Colombian sugar cane crops) in a solar, pilot-scale, compound parabolic collector (CPC) photoreactor using a slurry suspension of TiO(2). The ray-tracing technique was used jointly with the SFM to determine the direction of both the direct and diffuse solar photon fluxes and the spatial profile of the local volumetric rate of photon absorption (LVRPA) in the CPC reactor. Herbicides mineralization kinetics with explicit photon absorption effects were utilized to remove the dependence of the observed rate constants from the reactor geometry and radiation field in the photoreactor. The results showed that the overall model fitted the experimental data of herbicides mineralization in the solar CPC reactor satisfactorily for both cloudy and sunny days. Using the above approach kinetic parameters independent of the radiation field in the reactor can be estimated directly from the results of experiments carried out in a solar CPC reactor. The SFM combined with reaction kinetics and fluid-dynamic models proved to be a simple, but reliable model, for solar photocatalytic applications.

Synthesis gas method and apparatus

DOEpatents

Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie; Kosowski, Lawrence W; Robinson, Charles

2015-11-06

A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

Synthesis gas method and apparatus

DOEpatents

Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

2013-01-08

A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

10 CFR 2.621 - Acceptance and docketing of application for early review of site suitability issues in a combined...

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATORY COMMISSION RULES OF PRACTICE FOR DOMESTIC LICENSING PROCEEDINGS AND ISSUANCE OF ORDERS Additional... Issuance of Limited Work Authorizations Early Partial Decisions on Site Suitability-Combined License Under... Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation, as...

10 CFR 2.629 - Finality of partial decision on site suitability issues in a combined license proceeding.

Code of Federal Regulations, 2012 CFR

2012-01-01

... complete and acceptable for docketing under § 2.101(a)(3), the Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, shall determine whether the... a combined license proceeding. 2.629 Section 2.629 Energy NUCLEAR REGULATORY COMMISSION RULES OF...

10 CFR 2.629 - Finality of partial decision on site suitability issues in a combined license proceeding.

Code of Federal Regulations, 2011 CFR

2011-01-01

... complete and acceptable for docketing under § 2.101(a)(3), the Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation, as appropriate, shall determine whether the... a combined license proceeding. 2.629 Section 2.629 Energy NUCLEAR REGULATORY COMMISSION RULES OF...

10 CFR 140.96 - Appendix F-Indemnity locations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... construction area of the nuclear power reactor, as determined by the Commission. Such area will not necessarily... or combined license under 10 CFR part 52 is issued for such additional nuclear power reactors. (2) In... an existing nuclear power reactor, the geographical boundaries of the indemnity location shall...

Remediation of 1,2,3-trichlorobenzene contaminated soil using a combined thermal desorption-molten salt oxidation reactor system.

PubMed

Li, Jin-hui; Sun, Xiao-fei; Yao, Zhi-tong; Zhao, Xiang-yang

2014-02-01

A combined thermal desorption (TD)-molten salt oxidation (MSO) reactor system was applied to remediate the 1,2,3-trichlorobenzene (1,2,3-TCB) contaminated soil. The TD reactor was used to enrich the contaminant from soil, and its dechlorination of the contaminant was achieved in the MSO reactor. The optimum operating conditions of TD, and the effects of MSO reactor temperatures, additive amounts of the TCB on destruction and removal efficiency (DRE) of TCB and chlorine retention efficiency (CRE) were investigated. The reaction mechanism and pathway were proposed as well. The combined system could remediate the contaminated soil at a large scale of concentration from 5 to 25gkg(-1), and the DRE and CRE reached more than 99% and 95%, respectively, at temperatures above 850°C. The reaction emissions included C6H6, CH4, CO and CO2, and chlorinated species were not detected. It was found that a little increase in the temperature can considerably reduce the emission of C6H6, CH4, and CO, while the CO2 level increased. Copyright © 2014. Published by Elsevier Ltd.

Nanoparticulate-catalyzed oxygen transfer processes

DOEpatents

Hunt, Andrew T [Atlanta, GA; Breitkopf, Richard C [Dunwoody, GA

2009-12-01

Nanoparticulates of oxygen transfer materials that are oxides of rare earth metals, combinations of rare earth metals, and combinations of transition metals and rare earth metals are used as catalysts in a variety of processes. Unexpectedly large thermal efficiencies are achieved relative to micron sized particulates. Processes that use these catalysts are exemplified in a multistage reactor. The exemplified reactor cracks C6 to C20 hydrocarbons, desulfurizes the hydrocarbon stream and reforms the hydrocarbons in the stream to produce hydrogen. In a first reactor stage the steam and hydrocarbon are passed through particulate mixed rare earth metal oxide to crack larger hydrocarbon molecules. In a second stage, the steam and hydrocarbon are passed through particulate material that desulfurizes the hydrocarbon. In a third stage, the hydrocarbon and steam are passed through a heated, mixed transition metal/rare earth metal oxide to reform the lower hydrocarbons and thereby produce hydrogen. Stages can be alone or combined. Parallel reactors can provide continuous reactant flow. Each of the processes can be carried out individually.

Nuclear reactor shield including magnesium oxide

DOEpatents

Rouse, Carl A.; Simnad, Massoud T.

1981-01-01

An improvement in nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux, the reactor shielding including means providing structural support, neutron moderator material, neutron absorber material and other components as described below, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron.

Characterizing fluid dynamics in a bubble column aimed for the determination of reactive mass transfer

NASA Astrophysics Data System (ADS)

Kováts, Péter; Thévenin, Dominique; Zähringer, Katharina

2018-02-01

Bubble column reactors are multiphase reactors that are used in many process engineering applications. In these reactors a gas phase comes into contact with a fluid phase to initiate or support reactions. The transport process from the gas to the liquid phase is often the limiting factor. Characterizing this process is therefore essential for the optimization of multiphase reactors. For a better understanding of the transfer mechanisms and subsequent chemical reactions, a laboratory-scale bubble column reactor was investigated. First, to characterize the flow field in the reactor, two different methods have been applied. The shadowgraphy technique is used for the characterisation of the bubbles (bubble diameter, velocity, shape or position) for various process conditions. This technique is based on particle recognition with backlight illumination, combined with particle tracking velocimetry (PTV). The bubble trajectories in the column can also be obtained in this manner. Secondly, the liquid phase flow has been analysed by particle image velocimetry (PIV). The combination of both methods, delivering relevant information concerning disperse (bubbles) and continuous (liquid) phases, leads to a complete fluid dynamical characterization of the reactor, which is the pre-condition for the analysis of mass transfer between both phases.

10 CFR 2.629 - Finality of partial decision on site suitability issues in a combined license proceeding.

Code of Federal Regulations, 2014 CFR

2014-01-01

...), the Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation... 10 Energy 1 2014-01-01 2014-01-01 false Finality of partial decision on site suitability issues in a combined license proceeding. 2.629 Section 2.629 Energy NUCLEAR REGULATORY COMMISSION AGENCY RULES...

10 CFR 2.629 - Finality of partial decision on site suitability issues in a combined license proceeding.

Code of Federal Regulations, 2013 CFR

2013-01-01

...), the Director of the Office of New Reactors or the Director of the Office of Nuclear Reactor Regulation... 10 Energy 1 2013-01-01 2013-01-01 false Finality of partial decision on site suitability issues in a combined license proceeding. 2.629 Section 2.629 Energy NUCLEAR REGULATORY COMMISSION AGENCY RULES...

The effectiveness of using the combined-cycle technology in a nuclear power plant unit equipped with an SVBR-100 reactor

NASA Astrophysics Data System (ADS)

Kasilov, V. F.; Dudolin, A. A.; Gospodchenkov, I. V.

2015-05-01

The design of a modular SVBR-100 reactor with a lead-bismuth alloy liquid-metal coolant is described. The basic thermal circuit of a power unit built around the SVBR-100 reactor is presented together with the results of its calculation. The gross electrical efficiency of the turbine unit driven by saturated steam at a pressure of 6.7 MPa is estimated at η{el/gr} = 35.5%. Ways for improving the efficiency of this power unit and increasing its power output by applying gas-turbine and combined-cycle technologies are considered. With implementing a combined-cycle power-generating system comprising two GE-6101FA gas-turbine units with a total capacity of 140 MW, it becomes possible to obtain the efficiency of the combined-cycle plant equipped with the SVBR-100 reactor η{el/gr} = 45.39% and its electrical power output equal to 328 MW. The heat-recovery boiler used as part of this power installation generates superheated steam with a temperature of 560°C, due to which there is no need to use a moisture separator/steam reheater in the turbine unit thermal circuit.

76 FR 77021 - Notice of Availability of Combined License Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-09

... searching on Docket ID NRC-2008-0170 (William States Lee III Nuclear Station Units 1 and 2), NRC-2008-0231...://www.nrc.gov/reactors/new-reactors/col.html . FOR FURTHER INFORMATION CONTACT: Donald Habib, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 415-1035...

76 FR 71608 - Notice of Availability of Combined License Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-18

... searching on Docket ID NRC-2008-0170 (William States Lee III Nuclear Station Units 1 and 2), NRC-2008-0231...://www.nrc.gov/reactors/new-reactors/col.html . FOR FURTHER INFORMATION CONTACT: Donald Habib, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 415-1035...

76 FR 75566 - Notice of Availability of Combined License Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-02

....regulations.gov by searching on Docket ID NRC-2008-0170 (William States Lee III Nuclear Station Units 1 and 2... available at http://www.nrc.gov/reactors/new-reactors/col.html . FOR FURTHER INFORMATION CONTACT: Donald Habib, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone...

76 FR 72725 - Notice of Availability of Combined License Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-25

... searching on Docket ID NRC-2008-0170 (William States Lee III Nuclear Station Units 1 and 2), NRC-2008-0231...://www.nrc.gov/reactors/new-reactors/col.html . FOR FURTHER INFORMATION CONTACT: Donald Habib, Office of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 415-1035...

First Report on Non-Thermal Plasma Reactor Scaling Criteria and Optimization Models

DTIC Science & Technology

1998-01-13

decomposition chemistry of nitric oxide and two representative VOCs, trichloroethylene and carbon tetrachloride, and the connection between the basic plasma ... chemistry , the target species properties, and the reactor operating parameters. System architecture, that is how NTP reactors can be combined or ganged to achieve higher capacity, will also be briefly discussed.

10 CFR 2.340 - Initial decision in certain contested proceedings; immediate effectiveness of initial decisions...

Code of Federal Regulations, 2010 CFR

2010-01-01

... those matters, the Commission, the Director, Office of Nuclear Reactor Regulation or Director, Office of... Nuclear Reactor Regulation, as appropriate, after making the requisite findings, will issue, deny or... acceptance criteria in nuclear power reactor combined licenses. In any initial decision under § 52.103(g) of...

10 CFR 2.340 - Initial decision in certain contested proceedings; immediate effectiveness of initial decisions...

Code of Federal Regulations, 2011 CFR

2011-01-01

... those matters, the Commission, the Director, Office of Nuclear Reactor Regulation or Director, Office of... Nuclear Reactor Regulation, as appropriate, after making the requisite findings, will issue, deny or... acceptance criteria in nuclear power reactor combined licenses. In any initial decision under § 52.103(g) of...

10 CFR 2.340 - Initial decision in certain contested proceedings; immediate effectiveness of initial decisions...

Code of Federal Regulations, 2012 CFR

2012-01-01

... those matters, the Commission, the Director, Office of Nuclear Reactor Regulation or Director, Office of... Nuclear Reactor Regulation, as appropriate, after making the requisite findings, will issue, deny or... acceptance criteria in nuclear power reactor combined licenses. In any initial decision under § 52.103(g) of...

Validation of large-scale, monochromatic UV disinfection systems for drinking water using dyed microspheres.

PubMed

Blatchley, E R; Shen, C; Scheible, O K; Robinson, J P; Ragheb, K; Bergstrom, D E; Rokjer, D

2008-02-01

Dyed microspheres have been developed as a new method for validation of ultraviolet (UV) reactor systems. When properly applied, dyed microspheres allow measurement of the UV dose distribution delivered by a photochemical reactor for a given operating condition. Prior to this research, dyed microspheres had only been applied to a bench-scale UV reactor. The goal of this research was to extend the application of dyed microspheres to large-scale reactors. Dyed microsphere tests were conducted on two prototype large-scale UV reactors at the UV Validation and Research Center of New York (UV Center) in Johnstown, NY. All microsphere tests were conducted under conditions that had been used previously in biodosimetry experiments involving two challenge bacteriophage: MS2 and Qbeta. Numerical simulations based on computational fluid dynamics and irradiance field modeling were also performed for the same set of operating conditions used in the microspheres assays. Microsphere tests on the first reactor illustrated difficulties in sample collection and discrimination of microspheres against ambient particles. Changes in sample collection and work-up were implemented in tests conducted on the second reactor that allowed for improvements in microsphere capture and discrimination against the background. Under these conditions, estimates of the UV dose distribution from the microspheres assay were consistent with numerical simulations and the results of biodosimetry, using both challenge organisms. The combined application of dyed microspheres, biodosimetry, and numerical simulation offers the potential to provide a more in-depth description of reactor performance than any of these methods individually, or in combination. This approach also has the potential to substantially reduce uncertainties in reactor validation, thereby leading to better understanding of reactor performance, improvements in reactor design, and decreases in reactor capital and operating costs.

Development of Inspection and Repair Technology for Heat Exchanger Tubes in Fast Breeder Reactors

DTIC Science & Technology

2009-06-01

Technology for Heat Exchanger Tubes in Fast Breeder Reactors Akihiko NISHIMURA *1 , Takahisa SHOBU, Kiyoshi OKA, Toshihiko YAMAGUCHI, Yukihiro SHIMADA...fast breeder reactors (FBRs). It comprises a laser processing head combined with an eddy current testing unit. Ultrashort laser pulse ablation is used...be applied in the main- tenance of large structures such as nuclear reactors and chemical factories [1]. Internal access to a blanket cooling pipe

Analysis of microbial community adaptation in mesophilic hydrogen fermentation from food waste by tagged 16S rRNA gene pyrosequencing.

PubMed

Laothanachareon, Thanaporn; Kanchanasuta, Suwimon; Mhuanthong, Wuttichai; Phalakornkule, Chantaraporn; Pisutpaisal, Nipon; Champreda, Verawat

2014-11-01

Dark fermentation is an attractive process for generation of biohydrogen, which involves complex microbial processes on decomposition of organic wastes and subsequent conversion of metabolic intermediates to hydrogen. The microbes present in an upflow anaerobic sludge blanket (UASB) reactor for waste water treatment were tested for application in batch dark fermentation of food waste at varying ratios of feedstock to heat-treated microbial inoculum (F/M) of 1-8 (g TVS/g TVS). Biohydrogen yields between 0.39 and 2.68 mol H2/mol hexose were obtained, indicating that the yields were highly dependent on the starting F/M ratio. The highest H2 purity of 66% was obtained from the first 8 h of fermentation at the F/M ratio of 2, whereas the highest H2 production was obtained after 35 h of fermentation at the F/M ratio of 5. Tagged 16S rRNA gene pyrosequencing showed that the seed culture comprised largely of uncultured bacteria with various Proteobacteria, Bacteroidetes, and Firmicutes, while the starting food waste contained mainly lactic acid bacteria. Enrichment of Firmicutes, particularly Clostridia and lactic acid bacteria occurred within 8 h of the dark fermentation and the H2 producing microcosm at 35 h was dominated >80% by Clostridium spp. The major H2 producer was identified as a Clostridial strain related to Clostridium frigidicarnis. This work demonstrated the adaption of the microbial community during the dark fermentation of complex food waste and revealed the major roles of Clostridia in both substrate degradation and biohydrogen production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic digestibility of marine microalgae Phaeodactylum tricornutum in a lab-scale anaerobic membrane bioreactor.

PubMed

Zamalloa, Carlos; De Vrieze, Jo; Boon, Nico; Verstraete, Willy

2012-01-01

The biomass of industrially grown Phaeodactylum tricornutum was subjected in a novel way to bio-methanation at 33°C, i.e., in an anaerobic membrane bioreactor (AnMBR) at a hydraulic retention time of 2.5 days, at solid retention times of 20 to 10 days and at loading rates in the range of 2.6-5.9 g biomass-COD L(-1) day(-1) with membrane fluxes ranging from 1 to 0.8 L m(-2) h(-1). The total COD recovered as biogas was in the order of 52%. The input suspension was converted to a clear effluent rich in total ammonium nitrogen (546 mg TAN L(-1)) and phosphate (141 mg PO(4)-P L(-1)) usable as liquid fertilizer. The microbial community richness, dynamics, and organization in the reactor were interpreted using the microbial resource management approach. The AnMBR communities were found to be moderate in species richness and low in dynamics and community organization relative to UASB and conventional CSTR sludges. Quantitative polymerase chain reaction analysis revealed that Methanosaeta sp. was the dominant acetoclastic methanogen species followed by Methanosarcina sp. This work demonstrated that the use of AnMBR for the digestion of algal biomass is possible. The fact that some 50% of the organic matter is not liquefied means that the algal particulates in the digestate constitute a considerable fraction which should be valorized properly, for instance as slow release organic fertilizer. Overall, 1 kg of algae dry matter (DM) could be valorized in the form of biogas ( euro 2.07), N and P in the effluent (euro 0.02) and N and P in the digestate (euro 0.04), thus totaling about euro 2.13 per kilogram algae DM.

ETR, TRA642. ON GROUND FLOOR. THE 60TON ETR REACTOR VESSEL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ETR, TRA-642. ON GROUND FLOOR. THE 60-TON ETR REACTOR VESSEL IS DROPPED INTO PLACE OVER PIT. KAISER USED TWO MULTI-BLOCK DRUM PULLEYS WITH A COMBINED CAPACITY OF 100 TONS AND A 100-TON DRUM HOIST. THE VESSEL WAS 35 1/2 FEET LONG. INL NEGATIVE NO. 56-4149. R.G. Larsen, Photographer, 12/18/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Bioregenerative technologies for waste processing and resource recovery in advanced space life support system

NASA Technical Reports Server (NTRS)

Chamberland, Dennis

1991-01-01

The Controlled Ecological Life Support System (CELSS) for producing oxygen, water, and food in space will require an interactive facility to process and return wastes as resources to the system. This paper examines the bioregenerative techologies for waste processing and resource recovery considered for a CELSS Resource Recovery system. The components of this system consist of a series of biological reactors to treat the liquid and solid material fractions, in which the aerobic and anaerobic reactors are combined in a block called the Combined Reactor Equipment (CORE) block. The CORE block accepts the human wastes, kitchen wastes, inedible refractory plant materials, grey waters from the CELLS system, and aquaculture solids and processes these materials in either aerobic or anaerobic reactors depending on the desired product and the rates required by the integrated system.

Biological nutrient removal by internal circulation upflow sludge blanket reactor after landfill leachate pretreatment.

PubMed

Abood, Alkhafaji R; Bao, Jianguo; Abudi, Zaidun N

2013-10-01

The removal of biological nutrient from mature landfill leachate with a high nitrogen load by an internal circulation upflow sludge blanket (ICUSB) reactor was studied. The reactor is a set of anaerobic-anoxic-aerobic (A2/O) bioreactors, developed on the basis of an expended granular sludge blanket (EGSB), granular sequencing batch reactor (GSBR) and intermittent cycle extended aeration system (ICEAS). Leachate was subjected to stripping by agitation process and poly ferric sulfate coagulation as a pretreatment process, in order to reduce both ammonia toxicity to microorganisms and the organic contents. The reactor was operated under three different operating systems, consisting of recycling sludge with air (A2/O), recycling sludge without air (low oxygen) and a combination of both (A2/O and low oxygen). The lowest effluent nutrient levels were realised by the combined system of A2/O and low oxygen, which resulted in effluent of chemical oxygen demand (COD), NH3-N and biological oxygen demand (BOD5) concentrations of 98.20, 13.50 and 22.50 mg/L. The optimal operating conditions for the efficient removal of biological nutrient using the ICUSB reactor were examined to evaluate the influence of the parameters on its performance. The results showed that average removal efficiencies of COD and NH3-N of 96.49% and 99.39%, respectively were achieved under the condition of a hydraulic retention time of 12 hr, including 4 hr of pumping air into the reactor, with dissolved oxygen at an rate of 4 mg/L and an upflow velocity 2 m/hr. These combined processes were successfully employed and effectively decreased pollutant loading.

Liquid phase methanol reactor staging process for the production of methanol

DOEpatents

Bonnell, Leo W.; Perka, Alan T.; Roberts, George W.

1988-01-01

The present invention is a process for the production of methanol from a syngas feed containing carbon monoxide, carbon dioxide and hydrogen. Basically, the process is the combination of two liquid phase methanol reactors into a staging process, such that each reactor is operated to favor a particular reaction mechanism. In the first reactor, the operation is controlled to favor the hydrogenation of carbon monoxide, and in the second reactor, the operation is controlled so as to favor the hydrogenation of carbon dioxide. This staging process results in substantial increases in methanol yield.

An evaluation of alloys and coatings for use in automobile thermal reactors

NASA Technical Reports Server (NTRS)

Blankenship, C. P.; Oldrieve, R. E.

1974-01-01

Several candidate alloys and coatings were evaluated for use in automobile thermal reactors. Full-size reactors of the candidate materials were analyzed in cyclic engine dynamometer tests with peak temperature of 1900 F (1040 C). Two developmental ferritic iron alloys GE1541 and NASA-18T - exhibited the best overall performance lasting at least 60% of the life of the test engine. Four of the alloys evaluated warrant consideration for reactor use. They include GE1541, Armco 18 SR, NASA-18T, and Inconel 601. None of the commercial coating substrate combinations evaluated warrant consideration for reactor use.-

Evaluation of alloys and coatings for use in automobile thermal reactors

NASA Technical Reports Server (NTRS)

Blankenship, C. P.; Oldrieve, R. E.

1974-01-01

Several candidate alloys and coatings were evaluated for use in automobile thermal reactors. Full-size reactors of the candidate materials were evaluated in cyclic engine dynamometer tests with a peak temperature of 1040 C (1900 F). Two developmental ferritic-iron alloys, GE-1541 and NASA-18T, exhibited the best overall performance by lasting at least 60 percent of the life of test engine. Four of the alloys evaluated warrant consideration for reactor use. They are GE-1541, Armco 18 SR, NASA-18T, and Inconel 601. None of the commercial coating substrate combinations evaluated warrant consideration for reactor use.

Jet pump-drive system for heat removal

NASA Technical Reports Server (NTRS)

French, J. R. (Inventor)

1985-01-01

A jet pump, in combination with a TEMP, is employed to assure safe cooling of a nuclear reactor after shutdown. A TEMP, responsive to the heat from the coolant in the secondary flow path, automatically pumps the withdrawn coolant to a higher pressure and thus higher velocity compared to the main flow. The high velocity coolant is applied as a driver flow for the jet pump which has a main flow chamber located in the main flow circulation pump. Upon nuclear shutdown and loss of power for the main reactor pumping system, the TEMP/jet pump combination continues to boost the coolant flow in the direction it is already circulating. During the decay time for the nuclear reactor, the jet pump keeps running until the coolant temperature drops to a lower and safe temperature. At this lower temperature, the TEMP/jet jump combination ceases its circulation boosting operation. The TEMP/jet pump combination is automatic, self-regulating and provides an emergency pumping system free of moving parts.

Dense, layered membranes for hydrogen separation

DOEpatents

Roark, Shane E.; MacKay, Richard; Mundschau, Michael V.

2006-02-21

This invention provides hydrogen-permeable membranes for separation of hydrogen from hydrogen-containing gases. The membranes are multi-layer having a central hydrogen-permeable layer with one or more catalyst layers, barrier layers, and/or protective layers. The invention also relates to membrane reactors employing the hydrogen-permeable membranes of the invention and to methods for separation of hydrogen from a hydrogen-containing gas using the membranes and reactors. The reactors of this invention can be combined with additional reactor systems for direct use of the separated hydrogen.

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Astrophysics Data System (ADS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-09-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Technical Reports Server (NTRS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-01-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Membrane contactor/separator for an advanced ozone membrane reactor for treatment of recalcitrant organic pollutants in water

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

Chan, Wai Kit, E-mail: kekyeung@ust.hk; Joueet, Justine; Heng, Samuel

An advanced ozone membrane reactor that synergistically combines membrane distributor for ozone gas, membrane contactor for pollutant adsorption and reaction, and membrane separator for clean water production is described. The membrane reactor represents an order of magnitude improvement over traditional semibatch reactor design and is capable of complete conversion of recalcitrant endocrine disrupting compounds (EDCs) in water at less than three minutes residence time. Coating the membrane contactor with alumina and hydrotalcite (Mg/Al=3) adsorbs and traps the organics in the reaction zone resulting in 30% increase of total organic carbon (TOC) removal. Large surface area coating that diffuses surface chargesmore » from adsorbed polar organic molecules is preferred as it reduces membrane polarization that is detrimental to separation. - Graphical abstract: Advanced ozone membrane reactor synergistically combines membrane distributor for ozone, membrane contactor for sorption and reaction and membrane separator for clean water production to achieve an order of magnitude enhancement in treatment performance compared to traditional ozone reactor. Highlights: Black-Right-Pointing-Pointer Novel reactor using membranes for ozone distributor, reaction contactor and water separator. Black-Right-Pointing-Pointer Designed to achieve an order of magnitude enhancement over traditional reactor. Black-Right-Pointing-Pointer Al{sub 2}O{sub 3} and hydrotalcite coatings capture and trap pollutants giving additional 30% TOC removal. Black-Right-Pointing-Pointer High surface area coating prevents polarization and improves membrane separation and life.« less

Application of a combined process of moving-bed biofilm reactor (MBBR) and chemical coagulation for dyeing wastewater treatment.

PubMed

Shin, D H; Shin, W S; Kim, Y H; Han, Myung Ho; Choi, S J

2006-01-01

A combined process consisted of a Moving-Bed Biofilm Reactor (MBBR) and chemical coagulation was investigated for textile wastewater treatment. The pilot scale MBBR system is composed of three MBBRs (anaerobic, aerobic-1 and aerobic-2 in series), each reactor was filled with 20% (v/v) of polyurethane-activated carbon (PU-AC) carrier for biological treatment followed by chemical coagulation with FeCl2. ln the MBBR process, 85% of COD and 70% of color (influent COD = 807.5 mg/L and color = 3,400 PtCo unit) were removed using relatively low MLSS concentration and short hydraulic retention time (HRT = 44 hr). The biologically treated dyeing wastewater was subjected to chemical coagulation. After coagulation with FeCl2, 95% of COD and 97% of color were removed overall. The combined process of MBBR and chemical coagulation has promising potential for dyeing wastewater treatment.

NUCLEAR REACTOR FUEL-BREEDER FUEL ELEMENT

DOEpatents

Currier, E.L. Jr.; Nicklas, J.H.

1962-08-14

A fuel-breeder fuel element was developed for a nuclear reactor wherein discrete particles of fissionable material are dispersed in a matrix of fertile breeder material. The fuel element combines the advantages of a dispersion type and a breeder-type. (AEC)

Potential use of sugar binding proteins in reactors for regeneration of CO2 fixation acceptor D-Ribulose-1,5-bisphosphate

PubMed Central

Mahato, Sourav; De, Debojyoti; Dutta, Debajyoti; Kundu, Moloy; Bhattacharya, Sumana; Schiavone, Marc T; Bhattacharya, Sanjoy K

2004-01-01

Sugar binding proteins and binders of intermediate sugar metabolites derived from microbes are increasingly being used as reagents in new and expanding areas of biotechnology. The fixation of carbon dioxide at emission source has recently emerged as a technology with potentially significant implications for environmental biotechnology. Carbon dioxide is fixed onto a five carbon sugar D-ribulose-1,5-bisphosphate. We present a review of enzymatic and non-enzymatic binding proteins, for 3-phosphoglycerate (3PGA), 3-phosphoglyceraldehyde (3PGAL), dihydroxyacetone phosphate (DHAP), xylulose-5-phosphate (X5P) and ribulose-1,5-bisphosphate (RuBP) which could be potentially used in reactors regenerating RuBP from 3PGA. A series of reactors combined in a linear fashion has been previously shown to convert 3-PGA, (the product of fixed CO2 on RuBP as starting material) into RuBP (Bhattacharya et al., 2004; Bhattacharya, 2001). This was the basis for designing reactors harboring enzyme complexes/mixtures instead of linear combination of single-enzyme reactors for conversion of 3PGA into RuBP. Specific sugars in such enzyme-complex harboring reactors requires removal at key steps and fed to different reactors necessitating reversible sugar binders. In this review we present an account of existing microbial sugar binding proteins and their potential utility in these operations. PMID:15175111

Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

NASA Technical Reports Server (NTRS)

Lowry, S.; Krishnan, A.; Clark, I.

1999-01-01

The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

Startup of reactors for anoxic ammonium oxidation: experiences from the first full-scale anammox reactor in Rotterdam.

PubMed

van der Star, Wouter R L; Abma, Wiebe R; Blommers, Dennis; Mulder, Jan-Willem; Tokutomi, Takaaki; Strous, Marc; Picioreanu, Cristian; van Loosdrecht, Mark C M

2007-10-01

The first full-scale anammox reactor in the world was started in Rotterdam (NL). The reactor was scaled-up directly from laboratory-scale to full-scale and treats up to 750 kg-N/d. In the initial phase of the startup, anammox conversions could not be identified by traditional methods, but quantitative PCR proved to be a reliable indicator for growth of the anammox population, indicating an anammox doubling time of 10-12 days. The experience gained during this first startup in combination with the availability of seed sludge from this reactor, will lead to a faster startup of anammox reactors in the future. The anammox reactor type employed in Rotterdam was compared to other reactor types for the anammox process. Reactors with a high specific surface area like the granular sludge reactor employed in Rotterdam provide the highest volumetric loading rates. Mass transfer of nitrite into the biofilm is limiting the conversion of those reactor types that have a lower specific surface area. Now the first full-scale commercial anammox reactor is in operation, a consistent and descriptive nomenclature is suggested for reactors in which the anammox process is employed.

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations.

PubMed

Toh, Ren Wei; Li, Jie Sheng; Wu, Jie

2018-01-04

A new reaction screening technology for organic synthesis was recently demonstrated by combining elements from both continuous micro-flow and conventional batch reactors, coined stop-flow micro-tubing (SFMT) reactors. In SFMT, chemical reactions that require high pressure can be screened in parallel through a safer and convenient way. Cross-contamination, which is a common problem in reaction screening for continuous flow reactors, is avoided in SFMT. Moreover, the commercially available light-permeable micro-tubing can be incorporated into SFMT, serving as an excellent choice for light-mediated reactions due to a more effective uniform light exposure, compared to batch reactors. Overall, the SFMT reactor system is similar to continuous flow reactors and more superior than batch reactors for reactions that incorporate gas reagents and/or require light-illumination, which enables a simple but highly efficient reaction screening system. Furthermore, any successfully developed reaction in the SFMT reactor system can be conveniently translated to continuous-flow synthesis for large scale production.

Bioaugmentation of activated sludge towards 3-chloroaniline removal with a mixed bacterial population carrying a degradative plasmid.

PubMed

Bathe, Stephan; Schwarzenbeck, Norbert; Hausner, Martina

2009-06-01

A bioaugmentation approach combining several strategies was applied to achieve degradation of 3-chloroaniline (3CA) in semicontinuous activated sludge reactors. In a first step, a 3CA-degrading Comamonas testosteroni strain carrying the degradative plasmid pNB2 was added to a biofilm reactor, and complete 3CA degradation together with spread of the plasmid within the indigenous biofilm population was achieved. A second set of reactors was then bioaugmented with either a suspension of biofilm cells removed from the carrier material or with biofilm-containing carrier material. 3CA degradation was established rapidly in all bioaugmented reactors, followed by a slow adaptation of the non-bioaugmented control reactors. In response to variations in 3CA concentration, all reactors exhibited temporary performance breakdowns. Whereas duplicates of the control reactors deviated in their behaviour, the bioaugmented reactors appeared more reproducible in their performance and population dynamics. Finally, the carrier-bioaugmented reactors showed an improved performance in the presence of high 3CA influent concentrations over the suspension-bioaugmented reactors. In contrast, degradation in one control reactor failed completely, but was rapidly established in the remaining control reactor.

A mini-cavity probe reactor.

NASA Technical Reports Server (NTRS)

Hyland, R. E.

1971-01-01

The mini-cavity reactor is a rocket engine concept which combines the high specific impulse from a central gaseous fueled cavity (0.6 m diam) and NERVA type fuel elements in a driver region that is external to a moderator-reflector zone to produce a compact light weight reactor. The overall dimension including a pressure vessel that is located outside of the spherical reactor is approximately 1.21 m in diameter. Specific impulses up to 2000 sec are obtainable for 220 to 890 N of thrust with pressures less than 1000 atm. Powerplant weights including a radiator for disposing of the power in the driver region are between 4600 and 32,000 kg - less than payloads of the shuttle. This reactor could also be used as a test reactor for gas-core, MHD, breeding and materials research.

Performance evaluation of vinasse treatment plant integrated with physico-chemical methods.

PubMed

Ojha, Sanjay Kumar; Mishra, Snehasish; Kumar, Satish; Mohanty, Shakti Shankar; Sarkar, Biplab; Singh, Monika; Chaudhury, Gautam Roy

2015-11-01

With an objective to assess environmental management criteria of a vinasse treatment plant (VTP) and to evaluate the critical environmental parameters, a study was undertaken in a multi-product (packaged apple juice, distillery, brewery, packaged drinking water) brewery-cum-distillery unit. The facility with a volumetric loading rate of 11-15 kg COD m(-3).day, 3.6-4.5 h hydraulic retention time and 20 g l(-1) VSS had a scientifically managed technically sound effluent treatment system. While the water quality parameters were found within the acceptable limits, there was 99.07% reduction in BOD, from 43140.0 to 398.0 mg l(-1) and 98.61% reduction in COD from 98003.0 to 1357.0 mg l(-1). There was appreciable improvement in mixed liquor suspended solids (MLSS), mixed liquorvolatile suspended solids (MLVSS) and sludge volume index (SVI). A striking feature was the integrated aerobic-anaerobic highly efficient Up-flow Anaerobic Sludge Blanket (UASB) treatment for biodegradation and energy production that reduced energy and space needs, producing utilisable end-products and net savings on the operational cost. The end-point waste management included terminal products such as fertile sludge, cattle feed supplement, recyclable water and biogas. Vast lagoons with combined aerobic-anaerobic approaches, biogasification unit, sludge recovery, remediated irrigable water were the notable attributes.

Annular core liquid-salt cooled reactor with multiple fuel and blanket zones

DOEpatents

Peterson, Per F.

2013-05-14

A liquid fluoride salt cooled, high temperature reactor having a reactor vessel with a pebble-bed reactor core. The reactor core comprises a pebble injection inlet located at a bottom end of the reactor core and a pebble defueling outlet located at a top end of the reactor core, an inner reflector, outer reflector, and an annular pebble-bed region disposed in between the inner reflector and outer reflector. The annular pebble-bed region comprises an annular channel configured for receiving pebble fuel at the pebble injection inlet, the pebble fuel comprising a combination of seed and blanket pebbles having a density lower than the coolant such that the pebbles have positive buoyancy and migrate upward in said annular pebble-bed region toward the defueling outlet. The annular pebble-bed region comprises alternating radial layers of seed pebbles and blanket pebbles.

Treatment of mature landfill leachate by internal micro-electrolysis integrated with coagulation: a comparative study on a novel sequencing batch reactor based on zero valent iron.

PubMed

Ying, Diwen; Peng, Juan; Xu, Xinyan; Li, Kan; Wang, Yalin; Jia, Jinping

2012-08-30

A comparative study of treating mature landfill leachate with various treatment processes was conducted to investigate whether the method of combined processes of internal micro-electrolysis (IME) without aeration and IME with full aeration in one reactor was an efficient treatment for mature landfill leachate. A specifically designed novel sequencing batch internal micro-electrolysis reactor (SIME) with the latest automation technology was employed in the experiment. Experimental data showed that combined processes obtained a high COD removal efficiency of 73.7 ± 1.3%, which was 15.2% and 24.8% higher than that of the IME with and without aeration, respectively. The SIME reactor also exhibited a COD removal efficiency of 86.1 ± 3.8% to mature landfill leachate in the continuous operation, which is much higher (p<0.05) than that of conventional treatments of electrolysis (22.8-47.0%), coagulation-sedimentation (18.5-22.2%), and the Fenton process (19.9-40.2%), respectively. The innovative concept behind this excellent performance is a combination effect of reductive and oxidative processes of the IME, and the integration electro-coagulation. Optimal operating parameters, including the initial pH, Fe/C mass ratio, air flow rate, and addition of H(2)O(2), were optimized. All results show that the SIME reactor is a promising and efficient technology in treating mature landfill leachate. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthoil hydrodynamics. Combined third and fourth quarterly report, December 1, 1975--May 31, 1976

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

Brenner, H.; Prieve, D.C.; Fitch, B.

1977-08-01

This report deals with two-phase flow (gas and liquid) in a packed bed in the synthoil process reactor and preheater; in particular, nonuniform radial distribution of the liquid phase is studied. In addition, temperature profiles and possible instability of control due to the exothermic reactions are studied with respect to the synthoil reactor. This factor may limit the reactor diameter to about six inches. (LTN)

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

Not Available

The SPS Concept Development and Evaluation Program includes a comparative assessment. An early first step in the assessment process is the selection and characterization of alternative technologies. This document describes the cost and performance (i.e., technical and environmental) characteristics of six central station energy alternatives: (1) conventional coal-fired powerplant; (2) conventional light water reactor (LWR); (3) combined cycle powerplant with low-Btu gasifiers; (4) liquid metal fast breeder reactor (LMFBR); (5) photovoltaic system without storage; and (6) fusion reactor.

Transient Effects in Turbulence Modelling.

DTIC Science & Technology

1979-12-01

plenum region of a liquid-metal- cooled fast breeder reactor (LMFBR). The efficient heat transfer characteristics of liquid metal coolant, combined...Transients in Generalized Liquid-Metal Fast Breeder Reactor Outlet Plenums," Nuclear Technology, Vol. 44, July 1979, p. 210. 135 15. Lorenz, J. J., "MIX... Sodium Coolant in the Outlet Plenum of a Fast Nuclear Reactor ," Int. J. Heat Mass Transfer, Vol. 21, 1978, pp. 1565-1579. 19. Chen, Y. B., Golay, M. W

10 CFR 52.75 - Filing of applications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... New Reactors or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) The application... 10 Energy 2 2014-01-01 2014-01-01 false Filing of applications. 52.75 Section 52.75 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined...

10 CFR 52.75 - Filing of applications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... New Reactors or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) The application... 10 Energy 2 2011-01-01 2011-01-01 false Filing of applications. 52.75 Section 52.75 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined...

10 CFR 52.75 - Filing of applications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... New Reactors or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) The application... 10 Energy 2 2012-01-01 2012-01-01 false Filing of applications. 52.75 Section 52.75 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined...

10 CFR 52.75 - Filing of applications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... New Reactors or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) The application... 10 Energy 2 2010-01-01 2010-01-01 false Filing of applications. 52.75 Section 52.75 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined...

10 CFR 52.75 - Filing of applications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... New Reactors or Director, Office of Nuclear Reactor Regulation, as appropriate. (b) The application... 10 Energy 2 2013-01-01 2013-01-01 false Filing of applications. 52.75 Section 52.75 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined...

Landfill Leachate Toxicity Removal in Combined Treatment with Municipal Wastewater

PubMed Central

Kalka, J.

2012-01-01

Combined treatment of landfill leachate and municipal wastewater was performed in order to investigate the changes of leachate toxicity during biological treatment. Three laboratory A2O lab-scale reactors were operating under the same parameters (Q-8.5–10 L/d; HRT-1.4–1.6 d; MLSS 1.6–2.5 g/L) except for the influent characteristic and load. The influent of reactor I consisted of municipal wastewater amended with leachate from postclosure landfill; influent of reactor II consisted of leachate collected from transient landfill and municipal wastewater; reactor III served as a control and its influent consisted of municipal wastewater only. Toxicity of raw and treated wastewater was determinted by four acute toxicity tests with Daphnia magna, Thamnocephalus platyurus, Vibrio fischeri, and Raphidocelis subcapitata. Landfill leachate increased initial toxicity of wastewater. During biological treatment, significant decline of acute toxicity was observed, but still mixture of leachate and wastewater was harmful to all tested organisms. PMID:22623882

High-solid mesophilic methane fermentation of food waste with an emphasis on Iron, Cobalt, and Nickel requirements.

PubMed

Qiang, Hong; Lang, Dong-Li; Li, Yu-You

2012-01-01

The effect of trace metals on the mesophilic methane fermentation of high-solid food waste was investigated using both batch and continuous experiments. The continuous experiment was conducted by using a CSTR-type reactor with three run. During the first run, the HRT of the reactor was stepwise decreased from 100 days to 30 days. From operation day 50, the reactor efficiency deteriorated due to the lack of trace metals. The batch experiment showed that iron, cobalt, and nickel combinations had a significant effect on food waste. According to the results of the batch experiment, a combination of iron, cobalt, and nickel was added into the CSTR reactor by two different methods at run II, and III. Based on experimental results and theoretical calculations, the most suitable values of Fe/COD, Co/COD, and Ni/COD in the substrate were identified as 200, 6.0, and 5.7 mg/kg COD, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Boyack, B.E.; Steiner, J.L.; Harmony, S.C.

The PIUS advanced reactor is a 640-MWe pressurized water reactor concept developed by Asea Brown Boveri. A unique feature of PIUS is the absence of mechanical control and shutdown rods. Reactivity is controlled by coolant boron concentration and the temperature of the moderator coolant. Los Alamos supported the US Nuclear Regulatory Commission`s preapplication review of the PIUS reactor. Baseline calculations of the PIUS design were performed for active and passive reactor scrams using TRAC-PF1/MOD2. Additional sensitivity studies examined flow blockage and boron dilution events to explore the robustness of the PIUS concept for low-probability combination events following active-system scrams.

Integrated hydrocarbon reforming system and controls

DOEpatents

Clawson, Lawrence G.; Dorson, Matthew H.; Mitchell, William L.; Nowicki, Brian J.; Thijssen, Johannes; Davis, Robert; Papile, Christopher; Rumsey, Jennifer W.; Longo, Nathan; Cross, III, James C.; Rizzo, Vincent; Kleeburg, Gunther; Rindone, Michael; Block, Stephen G.; Sun, Maria; Morriseau, Brian D.; Hagan, Mark R.; Bowers, Brian

2003-11-04

A hydrocarbon reformer system including a first reactor configured to generate hydrogen-rich reformate by carrying out at least one of a non-catalytic thermal partial oxidation, a catalytic partial oxidation, a steam reforming, and any combinations thereof, a second reactor in fluid communication with the first reactor to receive the hydrogen-rich reformate, and having a catalyst for promoting a water gas shift reaction in the hydrogen-rich reformate, and a heat exchanger having a first mass of two-phase water therein and configured to exchange heat between the two-phase water and the hydrogen-rich reformate in the second reactor, the heat exchanger being in fluid communication with the first reactor so as to supply steam to the first reactor as a reactant is disclosed. The disclosed reformer includes an auxiliary reactor configured to generate heated water/steam and being in fluid communication with the heat exchanger of the second reactor to supply the heated water/steam to the heat exchanger.

Liquid fuel molten salt reactors for thorium utilization

DOE PAGES

Gehin, Jess C.; Powers, Jeffrey J.

2016-04-08

Molten salt reactors (MSRs) represent a class of reactors that use liquid salt, usually fluoride- or chloride-based, as either a coolant with a solid fuel (such as fluoride salt-cooled high temperature reactors) or as a combined coolant and fuel with fuel dissolved in a carrier salt. For liquid-fuelled MSRs, the salt can be processed online or in a batch mode to allow for removal of fission products as well as introduction of fissile fuel and fertile materials during reactor operation. The MSR is most commonly associated with the 233U/thorium fuel cycle, as the nuclear properties of 233U combined with themore » online removal of parasitic absorbers allow for the ability to design a thermal-spectrum breeder reactor; however, MSR concepts have been developed using all neutron energy spectra (thermal, intermediate, fast, and mixed-spectrum zoned concepts) and with a variety of fuels including uranium, thorium, plutonium, and minor actinides. Early MSR work was supported by a significant research and development (R&D) program that resulted in two experimental systems operating at ORNL in the 1960s, the Aircraft Reactor Experiment and the Molten Salt Reactor Experiment. Subsequent design studies in the 1970s focusing on thermal-spectrum thorium-fueled systems established reference concepts for two major design variants: (1) a molten salt breeder reactor (MSBR), with multiple configurations that could breed additional fissile material or maintain self-sustaining operation; and (2) a denatured molten salt reactor (DMSR) with enhanced proliferation-resistance. T MSRs has been selected as one of six most promising Generation IV systems and development activities have been seen in fast-spectrum MSRs, waste-burning MSRs, MSRs fueled with low-enriched uranium (LEU), as well as more traditional thorium fuel cycle-based MSRs. This study provides an historical background of MSR R&D efforts, surveys and summarizes many of the recent development, and provides analysis comparing thorium-based MSRs.« less

10 CFR 52.171 - Finality of manufacturing licenses; information requests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... required for issuance of a construction permit, operating license, combined license, in any hearing under... manufactured reactor, the costs and benefits of severe accident mitigation design alternatives, and the bases for not incorporating severe accident mitigation design alternatives into the design of the reactor to...

Aerosol reactor production of uniform submicron powders

NASA Technical Reports Server (NTRS)

Flagan, Richard C. (Inventor); Wu, Jin J. (Inventor)

1991-01-01

A method of producing submicron nonagglomerated particles in a single stage reactor includes introducing a reactant or mixture of reactants at one end while varying the temperature along the reactor to initiate reactions at a low rate. As homogeneously small numbers of seed particles generated in the initial section of the reactor progress through the reactor, the reaction is gradually accelerated through programmed increases in temperature along the length of the reactor to promote particle growth by chemical vapor deposition while minimizing agglomerate formation by maintaining a sufficiently low number concentration of particles in the reactor such that coagulation is inhibited within the residence time of particles in the reactor. The maximum temperature and minimum residence time is defined by a combination of temperature and residence time that is necessary to bring the reaction to completion. In one embodiment, electronic grade silane and high purity nitrogen are introduced into the reactor and temperatures of approximately 770.degree. K. to 1550.degree. K. are employed. In another embodiment silane and ammonia are employed at temperatures from 750.degree. K. to 1800.degree. K.

Aerosol reactor production of uniform submicron powders

DOEpatents

Flagan, Richard C.; Wu, Jin J.

1991-02-19

A method of producing submicron nonagglomerated particles in a single stage reactor includes introducing a reactant or mixture of reactants at one end while varying the temperature along the reactor to initiate reactions at a low rate. As homogeneously small numbers of seed particles generated in the initial section of the reactor progress through the reactor, the reaction is gradually accelerated through programmed increases in temperature along the length of the reactor to promote particle growth by chemical vapor deposition while minimizing agglomerate formation by maintaining a sufficiently low number concentration of particles in the reactor such that coagulation is inhibited within the residence time of particles in the reactor. The maximum temperature and minimum residence time is defined by a combination of temperature and residence time that is necessary to bring the reaction to completion. In one embodiment, electronic grade silane and high purity nitrogen are introduced into the reactor and temperatures of approximately 770.degree. K. to 1550.degree. K. are employed. In another embodiment silane and ammonia are employed at temperatures from 750.degree. K. to 1800.degree. K.

Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

DOEpatents

Badger, Phillip C.; Dunn, Jr., Kenneth J.

2015-09-01

A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

Effects of chlortetracycline, Cu and their combination on the performance and microbial community dynamics in swine manure anaerobic digestion.

PubMed

Wang, Rui; Zhang, Junya; Liu, Jibao; Yu, Dawei; Zhong, Hui; Wang, Yawei; Chen, Meixue; Tong, Juan; Wei, Yuansong

2018-05-01

Swine manure was typical for the combined pollution of heavy metals and antibiotics. The effects of widely used veterinary antibiotic chlortetracycline (CTC), Cu and their combination on swine manure anaerobic digestion performance and microbial community have never been investigated. Thus, four 2L anaerobic digestion reactors were established including reactor A (control), B (CTC spiked by 0.5g/kg dry weight, dw), C (Cu spiked by 5g/kg dw) and D (combination of CTC, 0.5g/kg dw, and Cu, 5g/kg dw), and dynamics of bacterial and archaeal community structure was investigated using high throughput sequencing method. Results showed that addition of CTC and Cu separately could increase the total biogas production by 21.6% and 15.8%, respectively, while combination of CTC and Cu severely inhibited anaerobic digestion (by 30.3%). Furthermore, corresponding to different stages and reactors, four kinds of microbes including bacteria and archaea were described in detail, and the effects of CTC, Cu and their combination mainly occurred at hydrolysis and acidification phases. The addition of Cu alone changed the dynamics of archaeal community significantly. It was genus Methanomassiliicoccus that dominated at the active methane production for A, B and D, while it was genus Methanobrevibacter and Methanoculleus for C. Copyright © 2017. Published by Elsevier B.V.

TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

EPA Science Inventory

The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

CATALYTIC OXIDATION OF METHANE AT LOW SPACE VELOCITIES.

DTIC Science & Technology

methane in airstream through an inhouse designed and fabricated stainless steel reactor. The reactor contained either Hopcalite , 5% V2O5 - 5% MoO3 on...plotted for each catalyst flow rate combination and the effect of space velocity on conversion at constant temperature is shown for the Hopcalite and

Hybrid reactor based on combined cavitation and ozonation: from concept to practical reality.

PubMed

Gogate, P R; Mededovic-Thagard, S; McGuire, D; Chapas, G; Blackmon, J; Cathey, R

2014-03-01

The present work gives an in depth discussion related to the development of a hybrid advanced oxidation reactor, which can be effectively used for the treatment of various types of water. The reactor is based on the principle of intensifying degradation/disinfection using a combination of hydrodynamic cavitation, acoustic cavitation, ozone injection and electrochemical oxidation/precipitation. Theoretical studies have been presented to highlight the uniform distribution of the cavitational activity and enhanced generation of hydroxyl radicals in the cavitation zone, as well as higher turbulence in the main reactor zone. The combination of these different oxidation technologies have been shown to result in enhanced water treatment ability, which can be attributed to the enhanced generation of hydroxyl radicals, enhanced contact of ozone and contaminants, and the elimination of mass transfer resistances during electrochemical oxidation/precipitation. Compared to the use of individual approaches, the hybrid reactor is expected to intensify the treatment process by 5-20 times, depending on the application in question, which can be confirmed based on the literature illustrations. Also, the use of Ozonix® has been successfully proven while processing recycled fluids at commercial sites on over 750 oil and natural gas wells during hydraulic operations around the United States. The superiority of the hybrid process over conventional chemical treatments in terms of bacteria and scale reduction as well as increased water flowability and better chemical compatibility, which is a key requirement for oil and gas applications, has been established. Copyright © 2013 Elsevier B.V. All rights reserved.

Decolourization of Rhodamine B: A swirling jet-induced cavitation combined with NaOCl.

PubMed

Mancuso, Giuseppe; Langone, Michela; Laezza, Marco; Andreottola, Gianni

2016-09-01

A hydrodynamic cavitation reactor (Ecowirl) based on swirling jet-induced cavitation has been used in order to allow the degradation of a waste dye aqueous solution (Rhodamine B, RhB). Cavitation generated by Ecowirl reactor was directly compared with cavitation generated by using multiple hole orifice plates. The effects of operating conditions and parameters such as pressure, pH of dye solution, initial concentration of RhB and geometry of the cavitating devices on the degradation rate of RhB were discussed. In similar operative conditions, higher extents of degradation (ED) were obtained using Ecowirl reactor rather than orifice plate. An increase in the ED from 8.6% to 14.7% was observed moving from hole orifice plates to Ecowirl reactor. Intensification in ED of RhB by using hydrodynamic cavitation in presence of NaOCl as additive has been studied. It was found that the decolourization was most efficient for the combination of hydrodynamic cavitation and chemical oxidation as compared to chemical oxidation and hydrodynamic cavitation alone. The value of ED of 83.4% was reached in 37min using Ecowirl combined with NaOCl (4.0mgL(-1)) as compared to the 100min needed by only mixing NaOCl at the same concentration. At last, the energetic consumptions of the cavitation devices have been evaluated. Increasing the ED and reducing the treatment time, Ecowirl reactor resulted to be more energy efficient as compared to hole orifice plates, Venturi and other swirling jet-induced cavitation devices, as reported in literature. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of alternative electric generation technologies for the SPS comparative assessment. Volume 1: Summary of central station technologies

NASA Astrophysics Data System (ADS)

1980-08-01

The technologies selected for the detailed characterization were: solar technology; terrestrial photovoltaic (200 MWe); coal technologies; conventional high sulfur coal combustion with advanced fine gas desulfurization (1250 MWe), and open cycle gas turbine combined cycle plant with low Btu gasifier (1250 MWe); and nuclear technologies: conventional light water reactor (1250 MWe), liquid metal fast breeder reactor (1250 MWe), and magnetic fusion reactor (1320 MWe). A brief technical summary of each power plant design is given.

Planetary surface reactor shielding using indigenous materials

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

Houts, Michael G.; Poston, David I.; Trellue, Holly R.

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials.

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

Gehin, Jess C.; Powers, Jeffrey J.

Molten salt reactors (MSRs) represent a class of reactors that use liquid salt, usually fluoride- or chloride-based, as either a coolant with a solid fuel (such as fluoride salt-cooled high temperature reactors) or as a combined coolant and fuel with fuel dissolved in a carrier salt. For liquid-fuelled MSRs, the salt can be processed online or in a batch mode to allow for removal of fission products as well as introduction of fissile fuel and fertile materials during reactor operation. The MSR is most commonly associated with the 233U/thorium fuel cycle, as the nuclear properties of 233U combined with themore » online removal of parasitic absorbers allow for the ability to design a thermal-spectrum breeder reactor; however, MSR concepts have been developed using all neutron energy spectra (thermal, intermediate, fast, and mixed-spectrum zoned concepts) and with a variety of fuels including uranium, thorium, plutonium, and minor actinides. Early MSR work was supported by a significant research and development (R&D) program that resulted in two experimental systems operating at ORNL in the 1960s, the Aircraft Reactor Experiment and the Molten Salt Reactor Experiment. Subsequent design studies in the 1970s focusing on thermal-spectrum thorium-fueled systems established reference concepts for two major design variants: (1) a molten salt breeder reactor (MSBR), with multiple configurations that could breed additional fissile material or maintain self-sustaining operation; and (2) a denatured molten salt reactor (DMSR) with enhanced proliferation-resistance. T MSRs has been selected as one of six most promising Generation IV systems and development activities have been seen in fast-spectrum MSRs, waste-burning MSRs, MSRs fueled with low-enriched uranium (LEU), as well as more traditional thorium fuel cycle-based MSRs. This study provides an historical background of MSR R&D efforts, surveys and summarizes many of the recent development, and provides analysis comparing thorium-based MSRs.« less

Prospects for development of an innovative water-cooled nuclear reactor for supercritical parameters of coolant

NASA Astrophysics Data System (ADS)

Kalyakin, S. G.; Kirillov, P. L.; Baranaev, Yu. D.; Glebov, A. P.; Bogoslovskaya, G. P.; Nikitenko, M. P.; Makhin, V. M.; Churkin, A. N.

2014-08-01

The state of nuclear power engineering as of February 1, 2014 and the accomplished elaborations of a supercritical-pressure water-cooled reactor are briefly reviewed, and the prospects of this new project are discussed based on this review. The new project rests on the experience gained from the development and operation of stationary water-cooled reactor plants, including VVERs, PWRs, BWRs, and RBMKs (their combined service life totals more than 15 000 reactor-years), and long-term experience gained around the world with operation of thermal power plants the turbines of which are driven by steam with supercritical and ultrasupercritical parameters. The advantages of such reactor are pointed out together with the scientific-technical problems that need to be solved during further development of such installations. The knowledge gained for the last decade makes it possible to refine the concept and to commence the work on designing an experimental small-capacity reactor.

Membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

PubMed

Rivero, M J; Parsons, S A; Jeffrey, P; Pidou, M; Jefferson, B

2006-01-01

Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

An numerical analysis of high-temperature helium reactor power plant for co-production of hydrogen and electricity

NASA Astrophysics Data System (ADS)

Dudek, M.; Podsadna, J.; Jaszczur, M.

2016-09-01

In the present work, the feasibility of using a high temperature gas cooled nuclear reactor (HTR) for electricity generation and hydrogen production are analysed. The HTR is combined with a steam and a gas turbine, as well as with the system for heat delivery for medium temperature hydrogen production. Industrial-scale hydrogen production using copper-chlorine (Cu-Cl) thermochemical cycle is considered and compared with high temperature electrolysis. Presented cycle shows a very promising route for continuous, efficient, large-scale and environmentally benign hydrogen production without CO2 emissions. The results show that the integration of a high temperature helium reactor, with a combined cycle for electric power generation and hydrogen production, may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

Integrated production of fuel gas and oxygenated organic compounds from synthesis gas

DOEpatents

Moore, Robert B.; Hegarty, William P.; Studer, David W.; Tirados, Edward J.

1995-01-01

An oxygenated organic liquid product and a fuel gas are produced from a portion of synthesis gas comprising hydrogen, carbon monoxide, carbon dioxide, and sulfur-containing compounds in a integrated feed treatment and catalytic reaction system. To prevent catalyst poisoning, the sulfur-containing compounds in the reactor feed are absorbed in a liquid comprising the reactor product, and the resulting sulfur-containing liquid is regenerated by stripping with untreated synthesis gas from the reactor. Stripping offgas is combined with the remaining synthesis gas to provide a fuel gas product. A portion of the regenerated liquid is used as makeup to the absorber and the remainder is withdrawn as a liquid product. The method is particularly useful for integration with a combined cycle coal gasification system utilizing a gas turbine for electric power generation.

Antineutrino analysis for continuous monitoring of nuclear reactors: Sensitivity study

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

Stewart, Christopher; Erickson, Anna

This paper explores the various contributors to uncertainty on predictions of the antineutrino source term which is used for reactor antineutrino experiments and is proposed as a safeguard mechanism for future reactor installations. The errors introduced during simulation of the reactor burnup cycle from variation in nuclear reaction cross sections, operating power, and other factors are combined with those from experimental and predicted antineutrino yields, resulting from fissions, evaluated, and compared. The most significant contributor to uncertainty on the reactor antineutrino source term when the reactor was modeled in 3D fidelity with assembly-level heterogeneity was found to be the uncertaintymore » on the antineutrino yields. Using the reactor simulation uncertainty data, the dedicated observation of a rigorously modeled small, fast reactor by a few-ton near-field detector was estimated to offer reduction of uncertainty on antineutrino yields in the 3.0–6.5 MeV range to a few percent for the primary power-producing fuel isotopes, even with zero prior knowledge of the yields.« less

Long lifetime fast spectrum reactor for lunar surface power system

NASA Astrophysics Data System (ADS)

Kambe, Mitsuru

1993-01-01

In the framework of innovative reactor research activities, a conceptual design study of fast spectrum reactor and primary system for 800 kWe lunar surface power system to be combined with potassium Rankine cycle power conversion has been conducted to meet the power requirements of the lunar base activities in the next century. The reactor subsystem is characterized by RAPID (Refueling by All Pins Integrated Design) concept to enhance inherent safety and to enable quick and simplifed refueling in every 10 years. RAPID concept affords power plant design lifetime of up to 30 years. Integrity of the reactor structure and replacement of failed primary circuits are also discussed. Substantial reduction in per-kWh cost on considering launch, emplacement, and final disposition can be expected by a long system lifetime.

Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor.

PubMed

Ranieri, Giuseppe; Mazzei, Rosalinda; Wu, Zhentao; Li, Kang; Giorno, Lidietta

2016-03-14

Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%), which remains constant after 6 reaction cycles.

NUCLEAR REACTOR

DOEpatents

Starr, C.

1963-01-01

This patent relates to a combination useful in a nuclear reactor and is comprised of a casing, a mass of graphite irapregnated with U compounds in the casing, and at least one coolant tube extending through the casing. The coolant tube is spaced from the mass, and He is irtroduced irto the space between the mass and the coolant tube. (AEC)

10 CFR 52.91 - Authorization to conduct limited work authorization activities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... determination required by 10 CFR 50.10(e), and the Director of New Reactors or the Director of Nuclear Reactor... activities. 52.91 Section 52.91 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.91 Authorization to conduct limited work...

10 CFR 52.91 - Authorization to conduct limited work authorization activities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... determination required by 10 CFR 50.10(e), and the Director of New Reactors or the Director of Nuclear Reactor... activities. 52.91 Section 52.91 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.91 Authorization to conduct limited work...

10 CFR 52.91 - Authorization to conduct limited work authorization activities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... determination required by 10 CFR 50.10(e), and the Director of New Reactors or the Director of Nuclear Reactor... activities. 52.91 Section 52.91 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.91 Authorization to conduct limited work...

10 CFR 52.91 - Authorization to conduct limited work authorization activities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... determination required by 10 CFR 50.10(e), and the Director of New Reactors or the Director of Nuclear Reactor... activities. 52.91 Section 52.91 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.91 Authorization to conduct limited work...

10 CFR 52.91 - Authorization to conduct limited work authorization activities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... determination required by 10 CFR 50.10(e), and the Director of New Reactors or the Director of Nuclear Reactor... activities. 52.91 Section 52.91 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Combined Licenses § 52.91 Authorization to conduct limited work...

Cure kinetics, morphologies, and mechanical properties of thermoplastic/MWCNT modified multifunctional glassy epoxies prepared via continuous reaction methods

NASA Astrophysics Data System (ADS)

Cheng, Xiaole

The primary goal of this dissertation is to develop a novel continuous reactor method to prepare partially cured epoxy prepolymers for aerospace prepreg applications with the aim of replacing traditional batch reactors. Compared to batch reactors, the continuous reactor is capable of solubilizing and dispersing a broad range of additives including thermoplastic tougheners, stabilizers, nanoparticles and curatives and advancing epoxy molecular weights and viscosities while reducing energy consumption. In order to prove this concept, polyethersulfone (PES) modified 4, 4'-diaminodiphenylsulfone (44DDS)/tetraglycidyl-4, 4'-diaminodiphenylmethane (TGDDM) epoxy prepolymers were firstly prepared using both continuous reactor and batch reactor methods. Kinetic studies confirmed the chain extension reaction in the continuous reactor is similar to the batch reactor, and the molecular weights and viscosities of prepolymers were readily controlled through reaction kinetics. Atomic force microscopy (AFM) confirmed similar cured network morphologies for formulations prepared from batch and continuous reactors. Additionally tensile strength, tensile modulus and fracture toughness analyses concluded mechanical properties of cured epoxy matrices produced from both reactors were equivalent. Effects of multifunctional epoxy compositions on thermoplastics phase-separated morphologies were systematically studied using a combination of AFM with nanomechanical mapping, spectroscopic and calorimetric techniques to provide new insights to tailor cured reaction induced phase separation (CRIPS) in multifunctional epoxy blend networks. Furthermore, how resultant crosslinked glassy polymer network and phase-separated morphologies correlated with mechanical properties are discussed in detail. Multiwall carbon nanotube (MWCNT)/TGDDM epoxy prepolymers were further prepared by combining the successful strategies for advancing epoxy chemistries and dispersing nanotubes using the continuous reactor. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the MWCNT dispersion states and stabilization in epoxy prepolymer matrix after continuous process and during curing cycles. Additionally, electrical conductivities and mechanical properties of final cured MWCNT/TGDDM composites were measured and discussed in view of their corresponding MWCNT dispersion states. Ternary blends of MWCNT reinforced thermoplastic/epoxy prepolymers were prepared by the continuous reactor. Influence of MWCNT on the CRIPS mechanism and the cured morphologies were systematically investigated using SEM and rheological analysis. Incorporation of MWCNT in thermoplastic/epoxy matrices can lead to a morphological transformation from phase inverted, to co-continuous, and to droplet dispersed morphology. In additional, dynamic mechanical analysis revealed the heterogeneity of MWCNT dispersion in thermoplastic/thermosets systems.

Flow-through biological conversion of lignocellulosic biomass

DOEpatents

Herring, Christopher D.; Liu, Chaogang; Bardsley, John

2014-07-01

The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars, or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.

454 pyrosequencing analyses of bacterial and archaeal richness in 21 full-scale biogas digesters.

PubMed

Sundberg, Carina; Al-Soud, Waleed A; Larsson, Madeleine; Alm, Erik; Yekta, Sepehr S; Svensson, Bo H; Sørensen, Søren J; Karlsson, Anna

2013-09-01

The microbial community of 21 full-scale biogas reactors was examined using 454 pyrosequencing of 16S rRNA gene sequences. These reactors included seven (six mesophilic and one thermophilic) digesting sewage sludge (SS) and 14 (ten mesophilic and four thermophilic) codigesting (CD) various combinations of wastes from slaughterhouses, restaurants, households, etc. The pyrosequencing generated more than 160,000 sequences representing 11 phyla, 23 classes, and 95 genera of Bacteria and Archaea. The bacterial community was always both more abundant and more diverse than the archaeal community. At the phylum level, the foremost populations in the SS reactors included Actinobacteria, Proteobacteria, Chloroflexi, Spirochetes, and Euryarchaeota, while Firmicutes was the most prevalent in the CD reactors. The main bacterial class in all reactors was Clostridia. Acetoclastic methanogens were detected in the SS, but not in the CD reactors. Their absence suggests that methane formation from acetate takes place mainly via syntrophic acetate oxidation in the CD reactors. A principal component analysis of the communities at genus level revealed three clusters: SS reactors, mesophilic CD reactors (including one thermophilic CD and one SS), and thermophilic CD reactors. Thus, the microbial composition was mainly governed by the substrate differences and the process temperature. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Proceedings of the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-7. Volume 3, Sessions 12-16

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

Block, R.C.; Feiner, F.

This document, Volume 3, includes papers presented at the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-7) September 10--15, 1995 at Saratoga Springs, N.Y. The following subjects are discussed: Progress in analytical and experimental work on the fundamentals of nuclear thermal-hydraulics, the development of advanced mathematical and numerical methods, ad the application of advancements in the field in the development of novel reactor concepts. Also combined issues of thermal-hydraulics and reactor/power-plant safety, core neutronics and/or radiation. Selected abstracts have been indexed separately for inclusion in the Energy Science and Technology Database.

Treatment of raw and ozonated oil sands process-affected water under decoupled denitrifying anoxic and nitrifying aerobic conditions: a comparative study.

PubMed

Xue, Jinkai; Zhang, Yanyan; Liu, Yang; Gamal El-Din, Mohamed

2016-11-01

Batch experiments were performed to evaluate biodegradation of raw and ozonated oil sands process-affected water (OSPW) under denitrifying anoxic and nitrifying aerobic conditions for 33 days. The results showed both the anoxic and aerobic conditions are effective in degrading OSPW classical and oxidized naphthenic acids (NAs) with the aerobic conditions demonstrating higher removal efficiency. The reactors under nitrifying aerobic condition reduced the total classical NAs of raw OSPW by 69.1 %, with better efficiency for species of higher hydrophobicity. Compared with conventional aerobic reactor, nitrifying aerobic condition substantially shortened the NA degradation half-life to 16 days. The mild-dose ozonation remarkably accelerated the subsequent aerobic biodegradation of classical NAs within the first 14 days, especially for those with long carbon chains. Moreover, the ozone pretreatment enhanced the biological removal of OSPW classical NAs by leaving a considerably lower final residual concentration of 10.4 mg/L under anoxic conditions, and 5.7 mg/L under aerobic conditions. The combination of ozonation and nitrifying aerobic biodegradation removed total classical NAs by 76.5 % and total oxy-NAs (O3-O6) by 23.6 %. 454 Pyrosequencing revealed that microbial species capable of degrading recalcitrant hydrocarbons were dominant in all reactors. The most abundant genus in the raw and ozonated anoxic reactors was Thauera (~56 % in the raw OSPW anoxic reactor, and ~65 % in the ozonated OSPW anoxic reactor); whereas Rhodanobacter (~40 %) and Pseudomonas (~40 %) dominated the raw and ozonated aerobic reactors, respectively. Therefore, the combination of mild-dose ozone pretreatment and subsequent biological process could be a competent choice for OSPW treatment.

Compatibility tests of materials for a lithium-cooled space power reactor concept

NASA Technical Reports Server (NTRS)

Sinclair, J. H.

1973-01-01

Materials for a lithium-cooled space power reactor concept must be chemically compatible for up to 50,000 hr at high temperature. Capsule tests at 1040 C (1900 F) were made of material combinations of prime interest: T-111 in direct contact with uranium mononitride (UN), Un in vacuum separated from T-111 by tungsten wire, UN with various oxygen impurity levels enclosed in tungsten wire lithium-filled T-111 capsules, and TZM and lithium together in T-111 capsules. All combinations were compatible for over 2800 hr except for T-111 in direct contact with UN.

Expert system for identification of simultaneous and sequential reactor fuel failures with gas tagging

DOEpatents

Gross, Kenny C.

1994-01-01

Failure of a fuel element in a nuclear reactor core is determined by a gas tagging failure detection system and method. Failures are catalogued and characterized after the event so that samples of the reactor's cover gas are taken at regular intervals and analyzed by mass spectroscopy. Employing a first set of systematic heuristic rules which are applied in a transformed node space allows the number of node combinations which must be processed within a barycentric algorithm to be substantially reduced. A second set of heuristic rules treats the tag nodes of the most recent one or two leakers as "background" gases, further reducing the number of trial node combinations. Lastly, a "fuzzy" set theory formalism minimizes experimental uncertainties in the identification of the most likely volumes of tag gases. This approach allows for the identification of virtually any number of sequential leaks and up to five simultaneous gas leaks from fuel elements.

Combined on-board hydride slurry storage and reactor system and process for hydrogen-powered vehicles and devices

DOEpatents

Brooks, Kriston P; Holladay, Jamelyn D; Simmons, Kevin L; Herling, Darrell R

2014-11-18

An on-board hydride storage system and process are described. The system includes a slurry storage system that includes a slurry reactor and a variable concentration slurry. In one preferred configuration, the storage system stores a slurry containing a hydride storage material in a carrier fluid at a first concentration of hydride solids. The slurry reactor receives the slurry containing a second concentration of the hydride storage material and releases hydrogen as a fuel to hydrogen-power devices and vehicles.

Planetary surface reactor shielding using indigenous materials

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

Houts, Michael G.; Poston, David I.; Trellue, Holly R.

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials. {copyright} {ital 1999 American Institute of Physics.}

Combination pipe-rupture mitigator and in-vessel core catcher. [LMFBR

DOEpatents

Tilbrook, R.W.; Markowski, F.J.

1982-03-09

A device is described which mitigates against the effects of a failed coolant loop in a nuclear reactor by restricting the outflow of coolant from the reactor through the failed loop and by retaining any particulated debris from a molten core which may result from coolant loss or other cause. The device reduces the reverse pressure drop through the failed loop by limiting the access of coolant in the reactor to the inlet of the failed loop. The device also spreads any particulated core debris over a large area to promote cooling.

Combination pipe rupture mitigator and in-vessel core catcher

DOEpatents

Tilbrook, Roger W.; Markowski, Franz J.

1983-01-01

A device which mitigates against the effects of a failed coolant loop in a nuclear reactor by restricting the outflow of coolant from the reactor through the failed loop and by retaining any particulated debris from a molten core which may result from coolant loss or other cause. The device reduces the reverse pressure drop through the failed loop by limiting the access of coolant in the reactor to the inlet of the failed loop. The device also spreads any particulated core debris over a large area to promote cooling.

Cleanup Verification Package for the 118-F-1 Burial Ground

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

E. J. Farris and H. M. Sulloway

2008-01-10

This cleanup verification package documents completion of remedial action for the 118-F-1 Burial Ground on the Hanford Site. This burial ground is a combination of two locations formerly called Minor Construction Burial Ground No. 2 and Solid Waste Burial Ground No. 2. This waste site received radioactive equipment and other miscellaneous waste from 105-F Reactor operations, including dummy elements and irradiated process tubing; gun barrel tips, steel sleeves, and metal chips removed from the reactor; filter boxes containing reactor graphite chips; and miscellaneous construction solid waste.

Short- and long-term responses to molybdenum-99 shortages in nuclear medicine.

PubMed

Ballinger, J R

2010-11-01

Most nuclear medicine studies use (99)Tc(m), which is the decay product of (99)Mo. The world supply of (99)Mo comes from only five nuclear research reactors and availability has been much reduced in recent times owing to problems at the largest reactors. In the short-term there are limited actions that can be taken owing to capacity issues on alternative imaging modalities. In the long-term, stability of (99)Mo supply will rely on a combination of replacing conventional reactors and developing new technologies.

Short- and long-term responses to molybdenum-99 shortages in nuclear medicine

PubMed Central

Ballinger, J R

2010-01-01

Most nuclear medicine studies use 99Tcm, which is the decay product of 99Mo. The world supply of 99Mo comes from only five nuclear research reactors and availability has been much reduced in recent times owing to problems at the largest reactors. In the short-term there are limited actions that can be taken owing to capacity issues on alternative imaging modalities. In the long-term, stability of 99Mo supply will rely on a combination of replacing conventional reactors and developing new technologies. PMID:20965898

The CANDU Reactor System: An Appropriate Technology.

PubMed

Robertson, J A

1978-02-10

CANDU power reactors are characterized by the combination of heavy water as moderator and pressure tubes to contain the fuel and coolant. Their excellent neutron economy provides the simplicity and low costs of once-through natural-uranium fueling. Future benefits include the prospect of a near-breeder thorium fuel cycle to provide security of fuel supply without the need to develop a new reactor such as the fast breeder. These and other features make the CANDU system an appropriate technology for countries, like Canada, of intermediate economic and industrial capacity.

77 FR 39521 - Applications and Amendments to Facility Operating Licenses and Combined Licenses Involving...

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PROSPECT - A precision oscillation and spectrum experiment

NASA Astrophysics Data System (ADS)

Langford, T. J.; PROSPECT Collaboration

2015-08-01

Segmented antineutrino detectors placed near a compact research reactor provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. Close proximity to a reactor combined with minimal overburden yield a high background environment that must be managed through shielding and detector technology. PROSPECT is a new experimental effort to detect reactor antineutrinos from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, managed by UT Battelle for the U.S. Department of Energy. The detector will use novel lithium-loaded liquid scintillator capable of neutron/gamma pulse shape discrimination and neutron capture tagging. These enhancements improve the ability to identify neutrino inverse-beta decays (IBD) and reject background events in analysis. Results from these efforts will be covered along with their implications for an oscillation search and a precision spectrum measurement.

[Isolation and characterization of Thermopirellula anaerolimosa gen. nov., sp. nov., an obligate anaerobic hydrogen-producing bacterium of the phylum Planctomycetes].

PubMed

Liu, Dongying; Liu, Yi; Men, Xuehui; Guo, Qunqun; Guo, Rongbo; Qiu, Yanling

2012-08-04

To cultivate various yet-to-be cultured heterotrophs from anaerobic granule sludge, we used a selective culture medium with low concentrations of substrates supplemented a variety of antibiotics. An obligate anaerobic, thermophilic, hydrogen-producing bacterium, strain VM20-7(T), was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain VM20-7(T) are non-motile, spherical, pear or teardrop shaped, occurring singly(o)r as aggregates (0.7 - 2.0 microm x 0.7 - 2.0 microm). Spore formation was not observed. Growth temperature ranges from 35 - 50 degrees C (optimum 45 degrees C), pH ranges from 6.0 - 8.3 (optimum 7.0 - 7.5) , NaCl tolerant concentration ranges from 0% - 0.5% (w/v, optimum 0% ). Nitrate, sulfate, thiosulfate, sulfite, elemental sulfur and Fe (III)-NTA were not used as terminal electron acceptors. Strain VM20-7(T) utilizes a wide range of carbohydrates, including glucose, maltose, ribose, xylose, sucrose, galactose, mannose, raffinose, pectin, yeast extract and xylan. Acetate and H2 are the main end products of glucose fermentation. The G + C content of the genomic DNA was 60.9 mol%. 16S rRNA gene sequence analysis revealed that it is related to the Pirellula-Rhodopirellula-Blastopirellula (PRB) clade within the order Planctomycetales (82.7 - 84.3% similarity with 16S rRNA genes of other known related species). The first obligate anaerobic bacterium within the phylum Planctomycetes was isolated with low concentration of carbohydrates and antibiotics. On the basis of the physiological and phylogenetic data, the name Thermopirellula anaerolimosa gen. nov. , sp. nov. is proposed for strain VM20-7(T) (= CGMCC 1.5169(T) = JCM 17478(T) = DSM 24165(T)).

Impacts of a participatory approach to assess sustainable sewage treatment technologies for urban fringe of Surat city in India.

PubMed

Vashi, A N; Shah, N C

2008-01-01

This paper describes the assessment of the sustainability of a number of different sewage treatment technologies by means of a multi-criteria, participatory method for a scattered settlement of urban fringe of Surat. The special efforts have been made for the broad participation to achieve stronger democracy, better quality of the end product, and a more effective process. The mere participation of technocrats and bureaucrats certainly lead to the greater efficiency in working methods. However, the ultimate goal of sustainable developments of such technologies could not be reached in absence of democratic participation and social learning. Keeping this important aspect in view for assessment of sustainability, the detailed study was conducted in the presence of policy makers and stakeholders, academicians, technical experts, finance managers and NGO, to find out sustainability criteria and indicators for three different sewage treatment technologies: (A) Conventional Activated Sludge Process (B) Extended Aeration System, and (C) Upflow Anaerobic Sludge Blanket (UASB) Reactor followed by Aerated Lagoon and Polishing Pond. Technologies were compared according to four criteria subdivided into twenty operational indicators. Criteria and indicators were evaluated as in a weighted-scale matrix. In India, sustainability criteria used in this type of comparisons are often restricted to a limited set of environmental impacts and financial costs but in this study additional criteria were evaluated including economic, social, and technical aspects. Based on the values assigned by the panel, the Sustainability Index (SI) was calculated for each technology. According to the SI and a predefined scale, sustainability was medium for options A and B, whereas high for option C. The purpose of this study is to provide a basis for the selection of a particular technology based on a rational and democratic assessment of its contribution to sustainability in the local and global context. IWA Publishing 2008.

Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

NASA Astrophysics Data System (ADS)

Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

2015-12-01

A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

NASA Technical Reports Server (NTRS)

Moran, Robert P.

2013-01-01

A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

Enhanced anaerobic degradation of Fischer-Tropsch wastewater by integrated UASB system with Fe-C micro-electrolysis assisted.

PubMed

Wang, Dexin; Ma, Wencheng; Han, Hongjun; Li, Kun; Xu, Hao; Fang, Fang; Hou, Baolin; Jia, Shengyong

2016-12-01

Coupling of the Fe-C micro-electrolysis (IC-ME) into the up-flow anaerobic sludge blanket (UASB) was developed for enhanced Fischer-Tropsch wastewater treatment. The COD removal efficiency and methane production in R 3 with IC-ME assisted both reached up to 80.6 ± 1.7% and 1.38 ± 0.11 L/L·d that higher than those values in R 1 with GAC addition (63.0 ± 3.4% and 0.95 ± 0.09 L/L·d) and R 2 with ZVI addition (74.5 ± 2.8% and 1.21 ± 0.09 L/L·d) under the optimum HRT (5 d). The Fe corrosion as electron donor reduced the ORP values and stimulated the activities of hydrogenotrophic methanogens to lower H 2 partial pressure in R 2 and R 3 . Additionally, Fe 2+ as by-product of iron corrosion, its presence could effectively increase the percentage of protein content in tightly bound extracellular polymeric substances (TB-EPS) to promote better bioflocculation, increasing to 90.5 mg protein/g·VSS (R 2 ) and 106.3 mg protein/g·VSS (R 3 ) while this value in R1 was simply 56.6 mg protein/g·VSS. More importantly, compared with R 1 , the excess accumulation of propionic acid and butyric acid in system was avoided. The macroscopic galvanic cells around Fe-C micro-electrolysis carriers in R 3 , that larger than microscopic galvanic cells in R 2 , further accelerate to transfer the electrons from anodic Fe to cathodic carbon that enhance interspecies hydrogen transfer, making the decomposition of propionic acid and butyric acid more thermodynamically feasible, finally facilitate more methane production. Copyright © 2016 Elsevier Ltd. All rights reserved.

10 CFR 52.98 - Finality of combined licenses; information requests.

Code of Federal Regulations, 2011 CFR

2011-01-01

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10 CFR 52.98 - Finality of combined licenses; information requests.

Code of Federal Regulations, 2010 CFR

2010-01-01

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10 CFR 52.98 - Finality of combined licenses; information requests.

Code of Federal Regulations, 2012 CFR

2012-01-01

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10 CFR 52.98 - Finality of combined licenses; information requests.

Code of Federal Regulations, 2014 CFR

2014-01-01

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10 CFR 52.98 - Finality of combined licenses; information requests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... condition of the combined license, the design of the facility, the inspections, tests, analyses, and acceptance criteria contained in the license which are not derived from a referenced standard design... chapter, as applicable. (b) If the combined license does not reference a design certification or a reactor...

Proceedings of the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-7. Sessions 17-24

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

Block, R.C.; Feiner, F.

1995-09-01

Technical papers accepted for presentation at the Seventh International Topical Meeting on Nuclear Reactor Thermal-Hydraulics are included in the present Proceedings. Except for the invited papers in the plenary session, all other papers are contributed papers. The topics of the meeting encompass all major areas of nuclear thermal-hydraulics, including analytical and experimental works on the fundamental mechanisms of fluid flow and heat transfer, the development of advanced mathematical and numerical methods, and the application of advancements in the field in the development of novel reactor concepts. Because of the complex nature of nuclear reactors and power plants, several papers dealmore » with the combined issues of thermal-hydraulics and reactor/power-plant safety, core neutronics and/or radiation. The participation in the conference by the authors from several countries and four continents makes the Proceedings a comprehensive review of the recent progress in the field of nuclear reactor thermal-hydraulics worldwide. Individual papers have been cataloged separately.« less

System Analysis for Decay Heat Removal in Lead-Bismuth Cooled Natural Circulated Reactors

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

Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki

2002-07-01

Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heatmore » removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in a primary circulation path is temporary reduced. However, the natural circulation is recovered by the PRACS system and the out let temperature decreases successfully. (authors)« less

System Analysis for Decay Heat Removal in Lead-Bismuth-Cooled Natural-Circulation Reactors

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

Sakai, Takaaki; Enuma, Yasuhiro; Iwasaki, Takashi

2004-03-15

Decay heat removal analyses for lead-bismuth-cooled natural-circulation reactors are described in this paper. A combined multidimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural-circulation reactors. For the preliminary study, transient analysis has been performed for a 300-MW(thermal) lead-bismuth-cooled reactor designed by Argonne National Laboratory. In addition, decay heat removal characteristics of a 400-MW(electric) lead-bismuth-cooled natural-circulation reactor designed by the Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. The primary reactor auxiliary cooling system (PRACS) is prepared for the JNC concept to get sufficient heat removal capacity. During 2000 smore » after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 deg. C because the buoyancy force in a primary circulation path is temporarily reduced. However, the natural circulation is recovered by the PRACS system, and the outlet temperature decreases successfully.« less

Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

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

Jiao, Zhujie; Was, Gary; Bartels, David

2015-04-02

This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that themore » effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.« less

Integral Design Methodology of Photocatalytic Reactors for Air Pollution Remediation.

PubMed

Passalía, Claudio; Alfano, Orlando M; Brandi, Rodolfo J

2017-06-07

An integral reactor design methodology was developed to address the optimal design of photocatalytic wall reactors to be used in air pollution control. For a target pollutant to be eliminated from an air stream, the proposed methodology is initiated with a mechanistic derived reaction rate. The determination of intrinsic kinetic parameters is associated with the use of a simple geometry laboratory scale reactor, operation under kinetic control and a uniform incident radiation flux, which allows computing the local superficial rate of photon absorption. Thus, a simple model can describe the mass balance and a solution may be obtained. The kinetic parameters may be estimated by the combination of the mathematical model and the experimental results. The validated intrinsic kinetics obtained may be directly used in the scaling-up of any reactor configuration and size. The bench scale reactor may require the use of complex computational software to obtain the fields of velocity, radiation absorption and species concentration. The complete methodology was successfully applied to the elimination of airborne formaldehyde. The kinetic parameters were determined in a flat plate reactor, whilst a bench scale corrugated wall reactor was used to illustrate the scaling-up methodology. In addition, an optimal folding angle of the corrugated reactor was found using computational fluid dynamics tools.

Flow-through biological conversion of lignocellulosic biomass

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

Herring, Christopher D.; Liu, Chaogang; Bardsley, John

2014-07-01

The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars,more » or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.« less

Tracking variations in fluorescent-dissolved organic matter in an aerobic submerged membrane bioreactor using excitation-emission matrix spectra combined with parallel factor analysis.

PubMed

Hur, Jin; Shin, Jaewon; Kang, Minsun; Cho, Jinwoo

2014-08-01

In this study, the variations in the fluorescent components of dissolved organic matter (DOM) were tracked for an aerobic submerged membrane bioreactor (MBR) at three different operation stages (cake layer formation, condensation, and after cleaning). The fluorescent DOM was characterized using excitation-emission matrix (EEM) spectroscopy combined with parallel factor analysis (PARAFAC). Non-aromatic carbon structures appear to be actively involved in the membrane fouling for the cake layer formation stage as revealed by much higher UV-absorbing DOM per organic carbon found in the effluent versus those inside the reactor. Four fluorescent components were successfully identified from the reactor and the effluent DOMs by EEM-PARAFAC modeling. Among those in the reactor, microbial humic-like fluorescence was the most abundant component at the cake layer formation stage and tryptophan-like fluorescence at the condensation stage. In contrast to the reactor, relatively similar composition of the PARAFAC components was exhibited for the effluent at all three stages. Tryptophan-like fluorescence displayed the largest difference between the reactor and the effluent, suggesting that this component could be a good tracer for membrane fouling. It appears that the fluorescent DOM was involved in membrane fouling by cake layer formation rather than by internal pore adsorption because its difference between the reactor and the effluent was the highest among all the four components, even after the membrane cleaning. Our study provided an insight into the fate and the behavior fluorescent DOM components for an MBR system, which could be an indicator of the membrane fouling.

Characterization of Used Nuclear Fuel with Multivariate Analysis for Process Monitoring

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

Dayman, Kenneth J.; Coble, Jamie B.; Orton, Christopher R.

2014-01-01

The Multi-Isotope Process (MIP) Monitor combines gamma spectroscopy and multivariate analysis to detect anomalies in various process streams in a nuclear fuel reprocessing system. Measured spectra are compared to models of nominal behavior at each measurement location to detect unexpected changes in system behavior. In order to improve the accuracy and specificity of process monitoring, fuel characterization may be used to more accurately train subsequent models in a full analysis scheme. This paper presents initial development of a reactor-type classifier that is used to select a reactor-specific partial least squares model to predict fuel burnup. Nuclide activities for prototypic usedmore » fuel samples were generated in ORIGEN-ARP and used to investigate techniques to characterize used nuclear fuel in terms of reactor type (pressurized or boiling water reactor) and burnup. A variety of reactor type classification algorithms, including k-nearest neighbors, linear and quadratic discriminant analyses, and support vector machines, were evaluated to differentiate used fuel from pressurized and boiling water reactors. Then, reactor type-specific partial least squares models were developed to predict the burnup of the fuel. Using these reactor type-specific models instead of a model trained for all light water reactors improved the accuracy of burnup predictions. The developed classification and prediction models were combined and applied to a large dataset that included eight fuel assembly designs, two of which were not used in training the models, and spanned the range of the initial 235U enrichment, cooling time, and burnup values expected of future commercial used fuel for reprocessing. Error rates were consistent across the range of considered enrichment, cooling time, and burnup values. Average absolute relative errors in burnup predictions for validation data both within and outside the training space were 0.0574% and 0.0597%, respectively. The errors seen in this work are artificially low, because the models were trained, optimized, and tested on simulated, noise-free data. However, these results indicate that the developed models may generalize well to new data and that the proposed approach constitutes a viable first step in developing a fuel characterization algorithm based on gamma spectra.« less

Damper mechanism for nuclear reactor control elements

DOEpatents

Taft, William Elwood

1976-01-01

A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping.

Method of preparing gas tags for identification of single and multiple failures of nuclear reactor fuel assemblies

DOEpatents

McCormick, Norman J.

1976-01-01

For use in the identification of failed fuel assemblies in a nuclear reactor, the ratios of the tag gas isotopic concentrations are located on curved surfaces to enable the ratios corresponding to failure of a single fuel assembly to be distinguished from those formed from any combination of two or more failed assemblies.

Enhanced organics and nitrogen removal in batch-operated vertical flow constructed wetlands by combination of intermittent aeration and step feeding strategy.

PubMed

Fan, Jinlin; Liang, Shuang; Zhang, Bo; Zhang, Jian

2013-04-01

Oxygen and carbon source supply are usually insufficient in subsurface flow constructed wetlands. Simultaneous removal of organic pollutants and nitrogen in five batch-operated vertical flow constructed wetlands under different operating conditions was investigated. Alternate aerobic and anaerobic regions were created well with intermittent aeration. Four-month experiments showed that the wetland-applied intermittent aeration combined with step feeding strategy (reactor E) greatly improved the removal of organics, ammonium nitrogen (NH4-N), and total nitrogen (TN) simultaneously, which were 97, 96, and 82%, respectively. It was much better than non-aerated reactors A and B and outperformed intermittently aerated reactor D without step feeding. Continuous aeration (reactor C) significantly enhanced the organics removal and nitrification, but it limited the TN removal (29%) seriously as a result of low denitrification level, and the high operation cost remained a question. The effect of plants was confirmed in this study, and the monitoring data showed that the plants could grow normally. Intermittent aeration as well as step feeding had no obvious influence on the growth of wetland plants in this study.

Vital area identification for U.S. Nuclear Regulatory Commission nuclear power reactor licensees and new reactor applicants.

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

Whitehead, Donnie Wayne; Varnado, G. Bruce

2008-09-01

U.S. Nuclear Regulatory Commission nuclear power plant licensees and new reactor applicants are required to provide protection of their plants against radiological sabotage, including the placement of vital equipment in vital areas. This document describes a systematic process for the identification of the minimum set of areas that must be designated as vital areas in order to ensure that all radiological sabotage scenarios are prevented. Vital area identification involves the use of logic models to systematically identify all of the malicious acts or combinations of malicious acts that could lead to radiological sabotage. The models available in the plant probabilisticmore » risk assessment and other safety analyses provide a great deal of the information and basic model structure needed for the sabotage logic model. Once the sabotage logic model is developed, the events (or malicious acts) in the model are replaced with the areas in which the events can be accomplished. This sabotage area logic model is then analyzed to identify the target sets (combinations of areas the adversary must visit to cause radiological sabotage) and the candidate vital area sets (combinations of areas that must be protected against adversary access to prevent radiological sabotage). Any one of the candidate vital area sets can be selected for protection. Appropriate selection criteria will allow the licensee or new reactor applicant to minimize the impacts of vital area protection measures on plant safety, cost, operations, or other factors of concern.« less

Sodium Based Heat Pipe Modules for Space Reactor Concepts: Stainless Steel SAFE-100 Core

NASA Technical Reports Server (NTRS)

Martin, James J.; Reid, Robert S.

2004-01-01

A heat pipe cooled reactor is one of several candidate reactor cores being considered for advanced space power and propulsion systems to support future space exploration applications. Long life heat pipe modules, with designs verified through a combination of theoretical analysis and experimental lifetime evaluations, would be necessary to establish the viability of any of these candidates, including the heat pipe reactor option. A hardware-based program was initiated to establish the infrastructure necessary to build heat pipe modules. This effort, initiated by Los Alamos National Laboratory and referred to as the Safe Affordable Fission Engine (SAFE) project, set out to fabricate and perform non-nuclear testing on a modular heat pipe reactor prototype that can provide 100 kilowatt from the core to an energy conversion system at 700 C. Prototypic heat pipe hardware was designed, fabricated, filled, closed-out and acceptance tested.

Appendix to HDC 2118 design criteria 100-X reactor water plant, general description - section II

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

Not Available

1952-03-29

The factors responsible for the advances of 100-X compared with the older areas are: Simplification of the process, such as elimination of separate process water clearwells, by having the filtered water reservoirs perform that function. Combination of separate buildings into one building, such as combining filter pump house and process pump house. Use of electric standby. Use of higher capacity pumps and filter basins, and so fewer number of units. Centralization of control and operation. More compact arrangement of plant components. Use of waste heat for space heating, recovered from reactor effluent, backed up by steam plant.

Anaerobic treatment as a core technology for energy, nutrients and water recovery from source-separated domestic waste(water).

PubMed

Zeeman, Grietje; Kujawa, Katarzyna; de Mes, Titia; Hernandez, Lucia; de Graaff, Marthe; Abu-Ghunmi, Lina; Mels, Adriaan; Meulman, Brendo; Temmink, Hardy; Buisman, Cees; van Lier, Jules; Lettinga, Gatze

2008-01-01

Based on results of pilot scale research with source-separated black water (BW) and grey water (GW), a new sanitation concept is proposed. BW and GW are both treated in a UASB (-septic tank) for recovery of CH4 gas. Kitchen waste is added to the anaerobic BW treatment for doubling the biogas production. Post-treatment of the effluent is providing recovery of phosphorus and removal of remaining COD and nitrogen. The total energy saving of the new sanitation concept amounts to 200 MJ/year in comparison with conventional sanitation, moreover 0.14 kg P/p/year and 90 litres of potential reusable water are produced. (c) IWA Publishing 2008.

Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

DOEpatents

Crawford, Douglas C.; Porter, Douglas L.; Hayes, Steven L.; Hill, Robert N.

1999-01-01

A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both.

RER SPECTRA OBTAINED WITH A MULTICRYSTAL SPECTROMETER

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

Austin, W.E.; Champion, W.R.

1959-11-01

Relative gamma spectra were obtained twenty feet from the Hadiation Effects Reactor. The measurements were made using a multicry-stal spectrometer. This design incorporates pair and anticompton spectrometers in combination. Two reactor configurations were used; with shield tanks empty- and water filled. The spectra were obtained before the fuel elements were run at high power. Consequently very little of the fission product spectrum is tntermined. (J.R.D.)

Advanced development of immobilized enzyme reactors

NASA Technical Reports Server (NTRS)

Jolly, Clifford D.; Schussel, Leonard J.; Carter, Layne

1991-01-01

Fixed-bed reactors have been used at NASA-Marshall to purify wastewater generated by an end-use equipment facility, on the basis of a combination of multifiltration unibeds and enzyme unibeds. The enzyme beds were found to effectively remove such targeted organics as urea, alcohols, and aldehydes, down to levels lying below detection limits. The enzyme beds were also found to remove organic contaminants not specifically targeted.

Reversal of OFI and CHF in Research Reactors Operating at 1 to 50 Bar. Version 1.0

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

Kalimullah, M.; Olson, A. P.; Dionne, B.

2014-02-28

The conditions at which the critical heat flux (CHF) and the heat flux at the onset of Ledinegg flow instability (OFI) are equal, are determined for a coolant channel with uniform heat flux as a function of five independent parameters: the channel exit pressure (P), heated length (Lh) , heated diameter (Dh), inlet temperature (Tin), and mass flux (G). A diagram is made by plotting the mass flux and heat flux at the OFI-CHF intersection (reversal from CHF > OFI to CHF < OFI as G increases) as a function of P (1 to 50 bar), for 36 combinations ofmore » the remaining three parameters (Lh , Dh , Tin): Lh = 0.28, 0.61, 1.18 m; Dh = 3, 4, 6, 8 mm; Tin = 30, 50, 70 °C. The use of the diagram to scope whether a research reactor is OFI-limited (below the curve) or CHF-limited based on the five parameters of its coolant channel is described. Justification for application of the diagram to research reactors with axially non-uniform heat flux is provided. Due to its limitations (uncertainties not included), the diagram cannot replace the detailed thermal-hydraulic analysis required for a reactor safety analysis. In order to make the OFI-CHF intersection diagram, two world-class CHF prediction methods (the Hall-Mudawar correlation and the extended Groeneveld 2006 table) are compared for 216 combinations of the five independent parameters. The two widely used OFI correlations (the Saha- Zuber and the Whittle-Forgan with η = 32.5) are also compared for the same combinations of the five parameters. The extended Groeneveld table and the Whittle-Forgan OFI correlation are selected for use in making the diagram. Using the above five design parameters, a research reactor can be represented by a point on the reversal diagram, and the diagram can be used to scope, without a thermal-hydraulic calculation, whether the OFI will occur before the CHF, or the CHF will occur before the OFI when the reactor power is increased keeping the five parameters fixed.« less

Can high fields save the tokamak? The challenge of steady-state operation for low cost compact reactors

NASA Astrophysics Data System (ADS)

Freidberg, Jeffrey; Dogra, Akshunna; Redman, William; Cerfon, Antoine

2016-10-01

The development of high field, high temperature superconductors is thought to be a game changer for the development of fusion power based on the tokamak concept. We test the validity of this assertion for pilot plant scale reactors (Q 10) for two different but related missions: pulsed operation and steady-state operation. Specifically, we derive a set of analytic criteria that determines the basic design parameters of a given fusion reactor mission. As expected there are far more constraints than degrees of freedom in any given design application. However, by defining the mission of the reactor under consideration, we have been able to determine the subset of constraints that drive the design, and calculate the values for the key parameters characterizing the tokamak. Our conclusions are as follows: 1) for pulsed reactors, high field leads to more compact designs and thus cheaper reactors - high B is the way to go; 2) steady-state reactors with H-mode like transport are large, even with high fields. The steady-state constraint is hard to satisfy in compact designs - high B helps but is not enough; 3) I-mode like transport, when combined with high fields, yields relatively compact steady-state reactors - why is there not more research on this favorable transport regime?

Fuel development for gas-cooled fast reactors

NASA Astrophysics Data System (ADS)

Meyer, M. K.; Fielding, R.; Gan, J.

2007-09-01

The Generation IV Gas-cooled Fast Reactor (GFR) concept is proposed to combine the advantages of high-temperature gas-cooled reactors (such as efficient direct conversion with a gas turbine and the potential for application of high-temperature process heat), with the sustainability advantages that are possible with a fast-spectrum reactor. The latter include the ability to fission all transuranics and the potential for breeding. The GFR is part of a consistent set of gas-cooled reactors that includes a medium-term Pebble Bed Modular Reactor (PBMR)-like concept, or concepts based on the Gas Turbine Modular Helium Reactor (GT-MHR), and specialized concepts such as the Very High-Temperature Reactor (VHTR), as well as actinide burning concepts [A Technology Roadmap for Generation IV Nuclear Energy Systems, US DOE Nuclear Energy Research Advisory Committee and the Generation IV International Forum, December 2002]. To achieve the necessary high power density and the ability to retain fission gas at high temperature, the primary fuel concept proposed for testing in the United States is dispersion coated fuel particles in a ceramic matrix. Alternative fuel concepts considered in the US and internationally include coated particle beds, ceramic clad fuel pins, and novel ceramic 'honeycomb' structures. Both mixed carbide and mixed nitride-based solid solutions are considered as fuel phases.

An underground nuclear power station using self-regulating heat-pipe controlled reactors

DOEpatents

Hampel, V.E.

1988-05-17

A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working fluid in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast- acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor. 5 figs.

Underground nuclear power station using self-regulating heat-pipe controlled reactors

DOEpatents

Hampel, Viktor E.

1989-01-01

A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working flud in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast-acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor.

Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

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

Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J.; Börner, K.

2015-12-15

A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steelmore » samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.« less

Evolution of titanium residue on the walls of a plasma-etching reactor and its effect on the polysilicon etching rate

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

Hirota, Kosa, E-mail: hirota-kousa@sme.hitachi-hitec.com; Itabashi, Naoshi; Tanaka, Junichi

2014-11-01

The variation in polysilicon plasma etching rates caused by Ti residue on the reactor walls was investigated. The amount of Ti residue was measured using attenuated total reflection Fourier transform infrared spectroscopy with the HgCdTe (MCT) detector installed on the side of the reactor. As the amount of Ti residue increased, the number of fluorine radicals and the polysilicon etching rate increased. However, a maximum limit in the etching rate was observed. A mechanism of rate variation was proposed, whereby F radical consumption on the quartz reactor wall is suppressed by the Ti residue. The authors also investigated a plasma-cleaningmore » method for the removal of Ti residue without using a BCl{sub 3} gas, because the reaction products (e.g., boron oxide) on the reactor walls frequently cause contamination of the product wafers during etching. CH-assisted chlorine cleaning, which is a combination of CHF{sub 3} and Cl{sub 2} plasma treatment, was found to effectively remove Ti residue from the reactor walls. This result shows that CH radicals play an important role in deoxidizing and/or defluorinating Ti residue on the reactor walls.« less

Toward the lowest energy consumption and emission in biofuel production: combination of ideal reactors and robust hosts.

PubMed

Xu, Ke; Lv, Bo; Huo, Yi-Xin; Li, Chun

2018-04-01

Rising feedstock costs, low crude oil prices, and other macroeconomic factors have threatened biofuel fermentation industries. Energy-efficient reactors, which provide controllable and stable biological environment, are important for the large-scale production of renewable and sustainable biofuels, and their optimization focus on the reduction of energy consumption and waste gas emission. The bioreactors could either be aerobic or anaerobic, and photobioreactors were developed for the culture of algae or microalgae. Due to the cost of producing large-volume bioreactors, various modeling strategies were developed for bioreactor design. The achievement of ideal biofuel reactor relies on not only the breakthrough of reactor design, but also the creation of super microbial factories with highest productivity and metabolic pathway flux. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combustion engine system

NASA Technical Reports Server (NTRS)

Houseman, John (Inventor); Voecks, Gerald E. (Inventor)

1986-01-01

A flow through catalytic reactor which selectively catalytically decomposes methanol into a soot free hydrogen rich product gas utilizing engine exhaust at temperatures of 200 to 650 C to provide the heat for vaporizing and decomposing the methanol is described. The reactor is combined with either a spark ignited or compression ignited internal combustion engine or a gas turbine to provide a combustion engine system. The system may be fueled entirely by the hydrogen rich gas produced in the methanol decomposition reactor or the system may be operated on mixed fuels for transient power gain and for cold start of the engine system. The reactor includes a decomposition zone formed by a plurality of elongated cylinders which contain a body of vapor permeable, methanol decomposition catalyst preferably a shift catalyst such as copper-zinc.

3D magnetohydrodynamic modelling of a dc low-current plasma arc batch reactor at very high pressure in helium

NASA Astrophysics Data System (ADS)

Lebouvier, A.; Iwarere, S. A.; Ramjugernath, D.; Fulcheri, L.

2013-04-01

This paper deals with a three-dimensional (3D) time-dependent magnetohydrodynamic (MHD) model under peculiar conditions of very high pressures (from 2 MPa up to 10 MPa) and low currents (<1 A). Studies on plasma arc working under these unusual conditions remain almost unexplored because of the technical and technological challenges to develop a reactor able to sustain a plasma at very high pressures. The combined effect of plasma reactivity and high pressure would probably open the way towards new promising applications in various fields: chemistry, lightning, materials or nanomaterial synthesis. A MHD model helps one to understand the complex and coupled phenomena surrounding the plasma which cannot be understood by simply experimentation. The model also provides data which are difficult to directly determine experimentally. The model simulates an experimental-based batch reactor working with helium. The particular reactor in question was used to investigate the Fischer-Tropsch application, fluorocarbon production and CO2 retro-conversion. However, as a first approach in terms of MHD, the model considers the case for helium as a non-reactive working gas. After a detailed presentation of the model, a reference case has been fully analysed (P = 8 MPa, I = 0.35 A) in terms of physical properties. The results show a bending of the arc and displacement of the anodic arc root towards the top of the reactor, due to the combined effects of convection, gravity and electromagnetic forces. A parametric study on the pressure (2-10 MPa) and current (0.25-0.4 A) was then investigated. The operating pressure does not show an influence on the contraction of the arc but higher pressures involve a higher natural convection in the reactor, driven by the density gradients between the cold and hot gas.

Proposal for a novel type of small scale aneutronic fusion reactor

NASA Astrophysics Data System (ADS)

Gruenwald, J.

2017-02-01

The aim of this work is to propose a novel scheme for a small scale aneutronic fusion reactor. This new reactor type makes use of the advantages of combining laser driven plasma acceleration and electrostatic confinement fusion. An intense laser beam is used to create a lithium-proton plasma with high density, which is then collimated and focused into the centre of the fusion reaction chamber. The basic concept presented here is based on the 7Li-proton fusion reaction. However, the physical and technological fundamentals may generally as well be applied to 11B-proton fusion. The former fusion reaction path offers higher energy yields while the latter has larger fusion cross sections. Within this paper a technological realisation of such a fusion device, which allows a steady state operation with highly energetic, well collimated ion beam, is presented. It will be demonstrated that the energetic break even can be reached with this device by using a combination of already existing technologies.

Combined Ceria Reduction and Methane Reforming in a Solar-Driven Particle-Transport Reactor.

PubMed

Welte, Michael; Warren, Kent; Scheffe, Jonathan R; Steinfeld, Aldo

2017-09-20

We report on the experimental performance of a solar aerosol reactor for carrying out the combined thermochemical reduction of CeO 2 and reforming of CH 4 using concentrated radiation as the source of process heat. The 2 kW th solar reactor prototype utilizes a cavity receiver enclosing a vertical Al 2 O 3 tube which contains a downward gravity-driven particle flow of ceria particles, either co-current or counter-current to a CH 4 flow. Experimentation under a peak radiative flux of 2264 suns yielded methane conversions up to 89% at 1300 °C for residence times under 1 s. The maximum extent of ceria reduction, given by the nonstoichiometry δ (CeO 2-δ ), was 0.25. The solar-to-fuel energy conversion efficiency reached 12%. The syngas produced had a H 2 :CO molar ratio of 2, and its calorific value was solar-upgraded by 24% over that of the CH 4 reformed.

Combined Ceria Reduction and Methane Reforming in a Solar-Driven Particle-Transport Reactor

PubMed Central

2017-01-01

We report on the experimental performance of a solar aerosol reactor for carrying out the combined thermochemical reduction of CeO2 and reforming of CH4 using concentrated radiation as the source of process heat. The 2 kWth solar reactor prototype utilizes a cavity receiver enclosing a vertical Al2O3 tube which contains a downward gravity-driven particle flow of ceria particles, either co-current or counter-current to a CH4 flow. Experimentation under a peak radiative flux of 2264 suns yielded methane conversions up to 89% at 1300 °C for residence times under 1 s. The maximum extent of ceria reduction, given by the nonstoichiometry δ (CeO2−δ), was 0.25. The solar-to-fuel energy conversion efficiency reached 12%. The syngas produced had a H2:CO molar ratio of 2, and its calorific value was solar-upgraded by 24% over that of the CH4 reformed. PMID:28966440

Verification of combined thermal-hydraulic and heat conduction analysis code FLOWNET/TRUMP

NASA Astrophysics Data System (ADS)

Maruyama, Soh; Fujimoto, Nozomu; Kiso, Yoshihiro; Murakami, Tomoyuki; Sudo, Yukio

1988-09-01

This report presents the verification results of the combined thermal-hydraulic and heat conduction analysis code, FLOWNET/TRUMP which has been utilized for the core thermal hydraulic design, especially for the analysis of flow distribution among fuel block coolant channels, the determination of thermal boundary conditions for fuel block stress analysis and the estimation of fuel temperature in the case of fuel block coolant channel blockage accident in the design of the High Temperature Engineering Test Reactor(HTTR), which the Japan Atomic Energy Research Institute has been planning to construct in order to establish basic technologies for future advanced very high temperature gas-cooled reactors and to be served as an irradiation test reactor for promotion of innovative high temperature new frontier technologies. The verification of the code was done through the comparison between the analytical results and experimental results of the Helium Engineering Demonstration Loop Multi-channel Test Section(HENDEL T(sub 1-M)) with simulated fuel rods and fuel blocks.

Expert system for identification of simultaneous and sequential reactor fuel failures with gas tagging

DOEpatents

Gross, K.C.

1994-07-26

Failure of a fuel element in a nuclear reactor core is determined by a gas tagging failure detection system and method. Failures are catalogued and characterized after the event so that samples of the reactor's cover gas are taken at regular intervals and analyzed by mass spectroscopy. Employing a first set of systematic heuristic rules which are applied in a transformed node space allows the number of node combinations which must be processed within a barycentric algorithm to be substantially reduced. A second set of heuristic rules treats the tag nodes of the most recent one or two leakers as background'' gases, further reducing the number of trial node combinations. Lastly, a fuzzy'' set theory formalism minimizes experimental uncertainties in the identification of the most likely volumes of tag gases. This approach allows for the identification of virtually any number of sequential leaks and up to five simultaneous gas leaks from fuel elements. 14 figs.

H-Coal process and plant design

DOEpatents

Kydd, Paul H.; Chervenak, Michael C.; DeVaux, George R.

1983-01-01

A process for converting coal and other hydrocarbonaceous materials into useful and more valuable liquid products. The process comprises: feeding coal and/or other hydrocarbonaceous materials with a hydrogen-containing gas into an ebullated catalyst bed reactor; passing the reaction products from the reactor to a hot separator where the vaporous and distillate products are separated from the residuals; introducing the vaporous and distillate products from the separator directly into a hydrotreater where they are further hydrogenated; passing the residuals from the separator successively through flash vessels at reduced pressures where distillates are flashed off and combined with the vaporous and distillate products to be hydrogenated; transferring the unseparated residuals to a solids concentrating and removal means to remove a substantial portion of solids therefrom and recycling the remaining residual oil to the reactor; and passing the hydrogenated vaporous and distillate products to an atmospheric fractionator where the combined products are fractionated into separate valuable liquid products. The hydrogen-containing gas is generated from sources within the process.

Regime Shift and Microbial Dynamics in a Sequencing Batch Reactor for Nitrification and Anammox Treatment of Urine ▿†

PubMed Central

Bürgmann, Helmut; Jenni, Sarina; Vazquez, Francisco; Udert, Kai M.

2011-01-01

The microbial population and physicochemical process parameters of a sequencing batch reactor for nitrogen removal from urine were monitored over a 1.5-year period. Microbial community fingerprinting (automated ribosomal intergenic spacer analysis), 16S rRNA gene sequencing, and quantitative PCR on nitrogen cycle functional groups were used to characterize the microbial population. The reactor combined nitrification (ammonium oxidation)/anammox with organoheterotrophic denitrification. The nitrogen elimination rate initially increased by 400%, followed by an extended period of performance degradation. This phase was characterized by accumulation of nitrite and nitrous oxide, reduced anammox activity, and a different but stable microbial community. Outwashing of anammox bacteria or their inhibition by oxygen or nitrite was insufficient to explain reactor behavior. Multiple lines of evidence, e.g., regime-shift analysis of chemical and physical parameters and cluster and ordination analysis of the microbial community, indicated that the system had experienced a rapid transition to a new stable state that led to the observed inferior process rates. The events in the reactor can thus be interpreted to be an ecological regime shift. Constrained ordination indicated that the pH set point controlling cycle duration, temperature, airflow rate, and the release of nitric and nitrous oxides controlled the primarily heterotrophic microbial community. We show that by combining chemical and physical measurements, microbial community analysis and ecological theory allowed extraction of useful information about the causes and dynamics of the observed process instability. PMID:21724875

Optofluidic reactors for reverse combustion photocatalytic production of hydrocarbons (Conference Presentation)

NASA Astrophysics Data System (ADS)

Schein, Perry; Erickson, David

2017-03-01

In combustion, hydrocarbon fuels are burned with oxygen to release energy, carbon dioxide and water vapor. Here, we introduce a photocatalytic reactor for reversing this process, when carbon dioxide and water are combined and using optical and thermal energy from the sun hydrocarbons are produced and oxygen is released. This allows for the sustainable production of hydrocarbon products from non-fossil sources, allowing for the development of "green" hydrocarbon products. Our reactors take the form of modular cells of 10 x 10 x 10 cm scale where light is delivered to nanostructured catalysts through the evanescent field around dielectric slab waveguides. The light distribution is optimized through the use of engineered scattering sites to enhance field uniformity. This is combined with integrated fluidic architecture to deliver a stream rich in water and carbon dioxide (such as exhaust from a natural gas burning plant) to the nanostructured catalyst particles in a narrow channel. Exhaust streams rich in oxygen and hydrocarbon products are collected at the outlet of the reactor cell. The cell is heated using solar thermal energy and temperatures of up to 200°C are achieved, enhancing reaction efficiency. Hydrocarbon products produced include methanol as well as other potentially useful molecules for fuel production or precursors to the manufacture of plastics. These reactors can be coupled to solar collectors to take advantage of the sun as a free source of heat and light, and the modular nature of the cells enables scaling to larger deployments.

Worldwide advanced nuclear power reactors with passive and inherent safety: What, why, how, and who

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

Forsberg, C.W.; Reich, W.J.

1991-09-01

The political controversy over nuclear power, the accidents at Three Mile Island (TMI) and Chernobyl, international competition, concerns about the carbon dioxide greenhouse effect and technical breakthroughs have resulted in a segment of the nuclear industry examining power reactor concepts with PRIME safety characteristics. PRIME is an acronym for Passive safety, Resilience, Inherent safety, Malevolence resistance, and Extended time after initiation of an accident for external help. The basic ideal of PRIME is to develop power reactors in which operator error, internal sabotage, or external assault do not cause a significant release of radioactivity to the environment. Several PRIME reactormore » concepts are being considered. In each case, an existing, proven power reactor technology is combined with radical innovations in selected plant components and in the safety philosophy. The Process Inherent Ultimate Safety (PIUS) reactor is a modified pressurized-water reactor, the Modular High Temperature Gas-Cooled Reactor (MHTGR) is a modified gas-cooled reactor, and the Advanced CANDU Project is a modified heavy-water reactor. In addition to the reactor concepts, there is parallel work on super containments. The objective is the development of a passive box'' that can contain radioactivity in the event of any type of accident. This report briefly examines: why a segment of the nuclear power community is taking this new direction, how it differs from earlier directions, and what technical options are being considered. A more detailed description of which countries and reactor vendors have undertaken activities follows. 41 refs.« less

Mathematical Modeling Of A Nuclear/Thermionic Power Source

NASA Technical Reports Server (NTRS)

Vandersande, Jan W.; Ewell, Richard C.

1992-01-01

Report discusses mathematical modeling to predict performance and lifetime of spacecraft power source that is integrated combination of nuclear-fission reactor and thermionic converters. Details of nuclear reaction, thermal conditions in core, and thermionic performance combined with model of swelling of fuel.

Search for eV sterile neutrinos at a nuclear reactor — the Stereo project

NASA Astrophysics Data System (ADS)

Haser, J.; Stereo Collaboration

2016-05-01

The re-analyses of the reference spectra of reactor antineutrinos together with a revised neutrino interaction cross section enlarged the absolute normalization of the predicted neutrino flux. The tension between previous reactor measurements and the new prediction is significant at 2.7 σ and is known as “reactor antineutrino anomaly”. In combination with other anomalies encountered in neutrino oscillation measurements, this observation revived speculations about the existence of a sterile neutrino in the eV mass range. Mixing of this light sterile neutrino with the active flavours would lead to a modification of the detected antineutrino flux. An oscillation pattern in energy and space could be resolved by a detector at a distance of few meters from a reactor core: the neutrino detector of the Stereo project will be located at about 10 m distance from the ILL research reactor in Grenoble, France. Lengthwise separated in six target cells filled with 2 m3 Gd-loaded liquid scintillator in total, the experiment will search for a position-dependent distortion in the energy spectrum.

Rapid starting methanol reactor system

DOEpatents

Chludzinski, Paul J.; Dantowitz, Philip; McElroy, James F.

1984-01-01

The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.

Thermal-Hydraulic Design of a Fluoride High-Temperature Demonstration Reactor

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

Carbajo, Juan J; Qualls, A L

2016-01-01

INTRODUCTION The Fluoride High-Temperature Reactor (FHR) named the Demonstration Reactor (DR) is a novel reactor concept using molten salt coolant and TRIstructural ISOtropic (TRISO) fuel that is being developed at Oak Ridge National Laboratory (ORNL). The objective of the FHR DR is to advance the technology readiness level of FHRs. The FHR DR will demonstrate technologies needed to close remaining gaps to commercial viability. The FHR DR has a thermal power of 100 MWt, very similar to the SmAHTR, another FHR ORNL concept (Refs. 1 and 2) with a power of 125 MWt. The FHR DR is also a smallmore » version of the Advanced High Temperature Reactor (AHTR), with a power of 3400 MWt, cooled by a molten salt and also being developed at ORNL (Ref. 3). The FHR DR combines three existing technologies: (1) high-temperature, low-pressure molten salt coolant, (2) high-temperature coated-particle TRISO fuel, (3) and passive decay heat cooling systems by using Direct Reactor Auxiliary Cooling Systems (DRACS). This paper presents FHR DR thermal-hydraulic design calculations.« less

10 CFR 2.629 - Finality of partial decision on site suitability issues in a combined license proceeding.

Code of Federal Regulations, 2010 CFR

2010-01-01

... a combined license proceeding. 2.629 Section 2.629 Energy NUCLEAR REGULATORY COMMISSION RULES OF... Work Authorizations Early Partial Decisions on Site Suitability-Combined License Under 10 Cfr Part 52... complete and acceptable for docketing under § 2.101(a)(3), the Director of the Office of New Reactors or...

Development of a thermal scheme for a cogeneration combined-cycle unit with an SVBR-100 reactor

NASA Astrophysics Data System (ADS)

Kasilov, V. F.; Dudolin, A. A.; Krasheninnikov, S. M.

2017-02-01

At present, the prospects for development of district heating that can increase the effectiveness of nuclear power stations (NPS), cut down their payback period, and improve protection of the environment against harmful emissions are being examined in the nuclear power industry of Russia. It is noted that the efficiency of nuclear cogeneration power stations (NCPS) is drastically affected by the expenses for heat networks and heat losses during transportation of a heat carrier through them, since NPSs are usually located far away from urban area boundaries as required for radiation safety of the population. The prospects for using cogeneration power units with small or medium power reactors at NPSs, including combined-cycle units and their performance indices, are described. The developed thermal scheme of a cogeneration combined-cycle unit (CCU) with an SBVR-100 nuclear reactor (NCCU) is presented. This NCCU should use a GE 6FA gasturbine unit (GTU) and a steam-turbine unit (STU) with a two-stage district heating plant. Saturated steam from the nuclear reactor is superheated in a heat-recovery steam generator (HRSG) to 560-580°C so that a separator-superheater can be excluded from the thermal cycle of the turbine unit. In addition, supplemental fuel firing in HRSG is examined. NCCU effectiveness indices are given as a function of the ambient air temperature. Results of calculations of the thermal cycle performance under condensing operating conditions indicate that the gross electric efficiency η el NCCU gr of = 48% and N el NCCU gr = 345 MW can be achieved. This efficiency is at maximum for NCCU with an SVBR-100 reactor. The conclusion is made that the cost of NCCU installed kW should be estimated, and the issue associated with NCCUs siting with reference to urban area boundaries must be solved.

Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

DOEpatents

Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Hill, R.N.

1999-03-23

A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both. 7 figs.

Hydrogen Production by Sorption Enhanced Steam Reforming (SESR) of Biomass in a Fluidised-Bed Reactor Using Combined Multifunctional Particles

PubMed Central

Zheng, Liya; Zhang, Zili; Fennell, Paul S.

2018-01-01

The performance of combined CO2-sorbent/catalyst particles for sorption enhanced steam reforming (SESR), prepared via a simple mechanical mixing protocol, was studied using a spout-fluidised bed reactor capable of continuous solid fuel (biomass) feeding. The influence of particle size (300–500 and 710–1000 µm), CaO loading (60–100 wt %), Ni-loading (10–40 wt %) and presence of dicalcium silicate support (22.6 wt %) on SESR process performance were investigated. The combined particles were characterised by their density, porosity and CO2 carrying capacity with the analysis by thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH) and mercury intrusion porosimetry (MIP). All experiments were conducted with continuous oak biomass feeding at a rate of 0.9 g/min ± 10%, and the reactor was operated at 660 ± 5 °C, 1 atm and 20 ± 2 vol % steam which corresponds to a steam-to-carbon ratio of 1.2:1. Unsupported combined particles containing 21.0 wt % Ni and 79 wt % CaO were the best performing sorbent/catalyst particle screened in this study, when accounting for the cost of Ni and the improvement in H2 produced by high Ni content particles. SESR tests with these combined particles produced 61 mmol H2/gbiomass (122 g H2/kgbiomass) at a purity of 61 vol %. Significant coke formation within the feeding tube and on the surfaces of the particles was observed which was attributed to the low steam to carbon ratio utilised. PMID:29883427

DIFFUSE: a FORTRAN program for design computation of tritium transport through thermonuclear reactor components by combined ordinary and thermal diffusion when the principal resistance to diffusion is the bulk metal

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

Pendergrass, J.H.

1977-10-01

Based on the theory developed in an earlier report, a FORTRAN computer program, DIFFUSE, was written. It computes, for design purposes, rates of transport of hydrogen isotopes by temperature-dependent quasi-unidirectional, and quasi-static combined ordinary and thermal diffusion through thin, hot thermonuclear reactor components that can be represented by composites of plane, cylindrical-shell, and spherical-shell elements when the dominant resistance to transfer is that of the bulk metal. The program is described, directions for its use are given, and a listing of the program, together with sample problem results, is presented.

Integrated process of distillation with side reactors for synthesis of organic acid esters

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

Panchal, Chandrakant B; Prindle, John C; Kolah, Aspri

An integrated process and system for synthesis of organic-acid esters is provided. The method of synthesizing combines reaction and distillation where an organic acid and alcohol composition are passed through a distillation chamber having a plurality of zones. Side reactors are used for drawing off portions of the composition and then recycling them to the distillation column for further purification. Water is removed from a pre-reactor prior to insertion into the distillation column. An integrated heat integration system is contained within the distillation column for further purification and optimizing efficiency in the obtaining of the final product.

Core disruptive accident margin seal

DOEpatents

Golden, Martin P.

1979-01-01

Apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus.

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

Boyack, B.E.; Steiner, J.L.; Harmony, S.C.

The PIUS advanced reactor is a 640-MWe pressurized water reactor concept developed by Asea Brown Boveri. A unique feature of PIUS is the absence of mechanical control and shutdown rods. Reactivity is controlled by coolant boron concentration and the temperature of the moderator coolant. Los Alamos is supporting the US Nuclear Regulatory Commission`s preapplication review of the PIUS reactor. Baseline calculations of the PIUS design were performed for a loss of offsite power initiator using TRAC-PF1/MOD2. Additional sensitivity studies examined flow blockage and boron dilution events to explore the robustness of the PIUS concept for low-probability combination events following amore » loss of offsite power.« less

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

Steiner, J.L.; Harmony, S.C.; Stumpf, H.J.

The PIUS advanced reactor is a 640-MWe pressurized water reactor concept developed by Asea Brown Boveri. A unique feature of PIUS is the absence of mechanical control and shutdown rods. Reactivity is controlled by coolant boron concentration and the temperature of the moderator coolant. Los Alamos is supporting the US Nuclear Regulatory Commission`s preapplication review of the PIUS reactor. Baseline calculations of the PIUS Supplement design were performed for a large-break loss-of-coolant (LBLOCA) initiator using TRAC-PF1/MOD2. Additional sensitivity studies examined flow blockage and boron dilution events to explore the robustness of the PIUS concept for low-probability combination events following anmore » LBLOCA.« less

Two stage hydrolysis of corn stover at high solids content for mixing power saving and scale-up applications.

PubMed

Liu, Ke; Zhang, Jian; Bao, Jie

2015-11-01

A two stage hydrolysis of corn stover was designed to solve the difficulties between sufficient mixing at high solids content and high power input encountered in large scale bioreactors. The process starts with the quick liquefaction to convert solid cellulose to liquid slurry with strong mixing in small reactors, then followed the comprehensive hydrolysis to complete saccharification into fermentable sugars in large reactors without agitation apparatus. 60% of the mixing energy consumption was saved by removing the mixing apparatus in large scale vessels. Scale-up ratio was small for the first step hydrolysis reactors because of the reduced reactor volume. For large saccharification reactors in the second step, the scale-up was easy because of no mixing mechanism was involved. This two stage hydrolysis is applicable for either simple hydrolysis or combined fermentation processes. The method provided a practical process option for industrial scale biorefinery processing of lignocellulose biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

Method for continuously recovering metals using a dual zone chemical reactor

DOEpatents

Bronson, Mark C.

1995-01-01

A dual zone chemical reactor continuously processes metal-containing materials while regenerating and circulating a liquid carrier. The starting materials are fed into a first reaction zone of a vessel containing a molten salt carrier. The starting materials react to form a metal product and a by-product that dissolves in the molten salt that flows to a second reaction zone in the reaction vessel. The second reaction zone is partitioned from, but in fluid communication with, the first reaction zone. The liquid carrier continuously circulates along a pathway between the first reaction zone and the second reaction zone. A reactive gas is introduced into the second reaction zone to react with the reaction by-product to generate the molten salt. The metal product, the gaseous waste products, and the excess liquid carrier are removed without interrupting the operation of the reactor. The design of the dual zone reactor can be adapted to combine a plurality of liquid carrier regeneration zones in a multiple dual zone chemical reactor for production scale processing.

Treatment of smuggled cigarette tobacco by composting process in facultative reactors.

PubMed

Zittel, Rosimara; Pinto da Silva, Cleber; Domingues, Cinthia Eloise; de Oliveira Stremel, Tatiana Roselena; de Almeida, Thiago Eduardo; Vieira Damiani, Gislaine; Xavier de Campos, Sandro

2018-01-01

This paper presents a study on the degradation of smuggled cigarette tobacco combined with domestic organic waste and sawdust or wood chips, using facultative reactor. Four reactors with different amounts of residue were assembled. For the study of the quality of the compost obtained, physicochemical, phytotoxicity and microbiological analyses were carried out. The mixture with wood chips presented the best temperature conditions and pH variation optimizing the degradation. The final germination index (GI) values of all treatments were above the recommended GI value (50%) and the final C/N ratio between 8 and 13 indicated a mature compost. The concentration of metals under study was below the limit allowed for the commercialization. The composting carried out in all facultative reactors provided ideal conditions for the total sterilization of the final compost. Therefore, the treatment of smuggled cigarettes through facultative reactors was efficient to produce stable and mature compost. Copyright © 2017 Elsevier Ltd. All rights reserved.

Successive and large-scale synthesis of InP/ZnS quantum dots in a hybrid reactor and their application to white LEDs

NASA Astrophysics Data System (ADS)

Kim, Kyungnam; Jeong, Sohee; Woo, Ju Yeon; Han, Chang-Soo

2012-02-01

We report successive and large-scale synthesis of InP/ZnS core/shell nanocrystal quantum dots (QDs) using a customized hybrid flow reactor, which is based on serial combination of a batch-type mixer and a flow-type furnace. InP cores and InP/ZnS core/shell QDs were successively synthesized in the hybrid reactor in a simple one-step process. In this reactor, the flow rate of the solutions was typically 1 ml min-1, 100 times larger than that of conventional microfluidic reactors. In order to synthesize high-quality InP/ZnS QDs, we controlled both the flow rate and the crystal growth temperature. Finally, we obtained high-quality InP/ZnS QDs in colors from bluish green to red, and we demonstrated that these core/shell QDs could be incorporated into white-light-emitting diode (LED) devices to improve color rendering performance.

Successive and large-scale synthesis of InP/ZnS quantum dots in a hybrid reactor and their application to white LEDs.

PubMed

Kim, Kyungnam; Jeong, Sohee; Woo, Ju Yeon; Han, Chang-Soo

2012-02-17

We report successive and large-scale synthesis of InP/ZnS core/shell nanocrystal quantum dots (QDs) using a customized hybrid flow reactor, which is based on serial combination of a batch-type mixer and a flow-type furnace. InP cores and InP/ZnS core/shell QDs were successively synthesized in the hybrid reactor in a simple one-step process. In this reactor, the flow rate of the solutions was typically 1 ml min(-1), 100 times larger than that of conventional microfluidic reactors. In order to synthesize high-quality InP/ZnS QDs, we controlled both the flow rate and the crystal growth temperature. Finally, we obtained high-quality InP/ZnS QDs in colors from bluish green to red, and we demonstrated that these core/shell QDs could be incorporated into white-light-emitting diode (LED) devices to improve color rendering performance.

Comparison of heavy metal toxicity in continuous flow and batch reactors

NASA Astrophysics Data System (ADS)

Sengor, S. S.; Gikas, P.; Moberly, J. G.; Peyton, B. M.; Ginn, T. R.

2009-12-01

The presence of heavy metals may significantly affect microbial growth. In many cases, small amounts of particular heavy metals may stimulate microbial growth; however, larger quantities may result in microbial growth reduction. Environmental parameters, such as growth pattern may alter the critical heavy metal concentration, above which microbial growth stimulation turns to growth inhibition. Thus, it is important to quantify the effects of heavy metals on microbial activity for understanding natural or manmade biological reactors, either in situ or ex situ. Here we compare the toxicity of Zn and Cu on Arthrobacter sp., a heavy metal tolerant microorganism, under continuous flow versus batch reactor operations. Batch and continuous growth tests of Arthrobacter sp. were carried out at various individual and combined concentrations of Zn and Cu. Biomass concentration (OD) was measured for both the batch and continuous reactors, whereas ATP, oxygen uptake rates and substrate concentrations were additionally measured for the continuous system. Results indicated that Cu was more toxic than Zn under all conditions for both systems. In batch reactors, all tested Zn concentrations up to 150 uM showed a stimulatory effect on microbial growth. However, in the case of mixed Zn and Cu exposures, the presence of Zn either eliminated (at the 50 uM level both Zn and Cu) or reduced by ~25% (at the 100 and 150 uM levels both Zn and Cu) the Cu-induced inhibition. In the continuous system, only one test involved combined Cu (40uM) and Zn (125uM) and this test showed similar results to the 40uM Cu continuous test, i.e., no reduction in inhibition. The specific ATP concentration, i.e., ATP/OD, results for the continuous reactor showed an apparent recovery for both Cu-treated populations, although neither the OD nor glucose data showed any recovery. This may reflect that the individual microorganisms that survived after the addition of heavy metals, kept maintaining the usual ATP levels, as before metal addition. The last may imply a short of adaptation by some microorganisms to the presence of heavy metals. Overall, the batch reactor tests underestimated significantly the heavy metal inhibition, as compared to the continuous flow reactors. Therefore, the results of batch reactor tests should be used with some caution when heavy metal inhibition is to be interpreted for continuous flow natural environmental systems, such as rivers or wetlands.

Multiscale Simulations of ALD in Cross Flow Reactors

DOE PAGES

Yanguas-Gil, Angel; Libera, Joseph A.; Elam, Jeffrey W.

2014-08-13

In this study, we have developed a multiscale simulation code that allows us to study the impact of surface chemistry on the coating of large area substrates with high surface area/high aspect-ratio features. Our code, based on open-source libraries, takes advantage of the ALD surface chemistry to achieve an extremely efficient two-way coupling between reactor and feature length scales, and it can provide simulated quartz crystal microbalance and mass spectrometry data at any point of the reactor. By combining experimental surface characterization with simple analysis of growth profiles in a tubular cross flow reactor, we are able to extract amore » minimal set of reactions to effectively model the surface chemistry, including the presence of spurious CVD, to evaluate the impact of surface chemistry on the coating of large, high surface area substrates.« less

Strategies for the startup of methanogenic inverse fluidized-bed reactors using colonized particles.

PubMed

Alvarado-Lassman, A; Sandoval-Ramos, A; Flores-Altamirano, M G; Vallejo-Cantú, N A; Méndez-Contreras, J M

2010-05-01

One of the inconveniences in the startup of methanogenic inverse fluidized-bed reactors (IFBRs) is the long period required for biofilm formation and stabilization of the system. Previous researchers have preferred to start up in batch mode to shorten stabilization times. Much less work has been done with continuous-mode startup for the IFBR configuration of reactors. In this study, we prepared two IFBRs with similar characteristics to compare startup times for batch- and continuous-operation modes. The reactors were inoculated with a small quantity of colonized particles and run for a period of 3 months, to establish the optimal startup strategy using synthetic media as a substrate (glucose as a source of carbon). After the startup stage, the continuous- and batch-mode reactors removed more than 80% of the chemical oxygen demand (COD) in 51 and 60 days of operation, respectively; however, at the end of the experiments, the continuous-mode reactor had more biomass attached to the support media than the batch-mode reactor. Both reactors developed fully covered support media, but only the continuous-mode reactor had methane yields close to the theoretical value that is typical of stable reactors. Then, a combined startup strategy was proposed, with industrial wastewater as the substrate, using a sequence of batch cycles followed by continuous operation, which allows stable operation at an organic loading rate of 20 g COD/L x d in 15 days. Using a fraction of colonized support as an inoculum presents advantages, with respect to previously reported strategies.

Utilization of 134Cs/137Cs in the environment to identify the reactor units that caused atmospheric releases during the Fukushima Daiichi accident

NASA Astrophysics Data System (ADS)

Chino, Masamichi; Terada, Hiroaki; Nagai, Haruyasu; Katata, Genki; Mikami, Satoshi; Torii, Tatsuo; Saito, Kimiaki; Nishizawa, Yukiyasu

2016-08-01

The Fukushima Daiichi nuclear power reactor units that generated large amounts of airborne discharges during the period of March 12-21, 2011 were identified individually by analyzing the combination of measured 134Cs/137Cs depositions on ground surfaces and atmospheric transport and deposition simulations. Because the values of 134Cs/137Cs are different in reactor units owing to fuel burnup differences, the 134Cs/137Cs ratio measured in the environment was used to determine which reactor unit ultimately contaminated a specific area. Atmospheric dispersion model simulations were used for predicting specific areas contaminated by each dominant release. Finally, by comparing the results from both sources, the specific reactor units that yielded the most dominant atmospheric release quantities could be determined. The major source reactor units were Unit 1 in the afternoon of March 12, 2011, Unit 2 during the period from the late night of March 14 to the morning of March 15, 2011. These results corresponded to those assumed in our previous source term estimation studies. Furthermore, new findings suggested that the major source reactors from the evening of March 15, 2011 were Units 2 and 3 and that the dominant source reactor on March 20, 2011 temporally changed from Unit 3 to Unit 2.

Utilization of (134)Cs/(137)Cs in the environment to identify the reactor units that caused atmospheric releases during the Fukushima Daiichi accident.

PubMed

Chino, Masamichi; Terada, Hiroaki; Nagai, Haruyasu; Katata, Genki; Mikami, Satoshi; Torii, Tatsuo; Saito, Kimiaki; Nishizawa, Yukiyasu

2016-08-22

The Fukushima Daiichi nuclear power reactor units that generated large amounts of airborne discharges during the period of March 12-21, 2011 were identified individually by analyzing the combination of measured (134)Cs/(137)Cs depositions on ground surfaces and atmospheric transport and deposition simulations. Because the values of (134)Cs/(137)Cs are different in reactor units owing to fuel burnup differences, the (134)Cs/(137)Cs ratio measured in the environment was used to determine which reactor unit ultimately contaminated a specific area. Atmospheric dispersion model simulations were used for predicting specific areas contaminated by each dominant release. Finally, by comparing the results from both sources, the specific reactor units that yielded the most dominant atmospheric release quantities could be determined. The major source reactor units were Unit 1 in the afternoon of March 12, 2011, Unit 2 during the period from the late night of March 14 to the morning of March 15, 2011. These results corresponded to those assumed in our previous source term estimation studies. Furthermore, new findings suggested that the major source reactors from the evening of March 15, 2011 were Units 2 and 3 and that the dominant source reactor on March 20, 2011 temporally changed from Unit 3 to Unit 2.

Utilization of 134Cs/137Cs in the environment to identify the reactor units that caused atmospheric releases during the Fukushima Daiichi accident

PubMed Central

Chino, Masamichi; Terada, Hiroaki; Nagai, Haruyasu; Katata, Genki; Mikami, Satoshi; Torii, Tatsuo; Saito, Kimiaki; Nishizawa, Yukiyasu

2016-01-01

The Fukushima Daiichi nuclear power reactor units that generated large amounts of airborne discharges during the period of March 12–21, 2011 were identified individually by analyzing the combination of measured 134Cs/137Cs depositions on ground surfaces and atmospheric transport and deposition simulations. Because the values of 134Cs/137Cs are different in reactor units owing to fuel burnup differences, the 134Cs/137Cs ratio measured in the environment was used to determine which reactor unit ultimately contaminated a specific area. Atmospheric dispersion model simulations were used for predicting specific areas contaminated by each dominant release. Finally, by comparing the results from both sources, the specific reactor units that yielded the most dominant atmospheric release quantities could be determined. The major source reactor units were Unit 1 in the afternoon of March 12, 2011, Unit 2 during the period from the late night of March 14 to the morning of March 15, 2011. These results corresponded to those assumed in our previous source term estimation studies. Furthermore, new findings suggested that the major source reactors from the evening of March 15, 2011 were Units 2 and 3 and that the dominant source reactor on March 20, 2011 temporally changed from Unit 3 to Unit 2. PMID:27546490

Co-digestion performance of organic fraction of municipal solid waste with leachate: Preliminary studies.

PubMed

Guven, Huseyin; Akca, Mehmet Sadik; Iren, Erol; Keles, Fatih; Ozturk, Izzet; Altinbas, Mahmut

2018-01-01

The main aim of the study was to evaluate the co-digestion performance of OFMSW with different wastes. Leachate, reverse osmosis (RO) concentrate collected from a leachate treatment facility and dewatered sewage sludge taken from a wastewater treatment plant (WWTP) were used for co-digestion in this paper. An extra effort was made to observe the effect of leachate inclusion in the co-digestion. In the study, the mono-digestion of OFMSW, leachate, RO concentrate and sewage sludge as well as digestion of 7 different waste mixtures were carried out for this objective. The experiments were carried out for approximately 50days under mesophilic conditions. The highest methane yield was 785L CH 4 /kg VS added in the reactor, which had only OFMSW. While the methane yield derived from OFMSW was found higher than previous studies, methane yield of leachate was found to be 110L CH 4 /kg VS added , which was lower than findings in the literature. The mono-substrate of OFMSW was followed by the reactor of having waste mixture of leachate+sewage sludge+OFMSW+water (C7) with 391L CH 4 /kg VS added , which was the only combination included water. In order to understand the effect of leachate and water inclusions on co-digestion, two separate waste combinations; leachate+sewage sludge+OFMSW+water (C7) and leachate+sewage sludge+OFMSW (C1) were prepared that had different amounts of leachate but same amounts of other wastes. The methane yield of leachate+sewage sludge+OFMSW+water (C7) indicated that addition of some water instead of leachate could stimulate biogas production. Methane yield of this reactor was found to be 71% higher than the waste combination of leachate+sewage sludge+OFMSW (C1). It could be thought that the high amount of non-biodegradable matters in leachate could be responsible for lower methane yield in leachate+sewage sludge+OFMSW (C1) reactor. Methane yields of the reactors showed that co-digestion of OFMSW and leachate could be a solution not only for treatment of leachate and but also increasing the biogas potential of leachate. Leachate addition could also adjust optimum total solids (TS) content in anaerobic digestion. It was also understood that RO concentrate did not affect the methane yield in a negative way. The similar characterization of leachate and RO concentrate in this study could offer the utilization of RO concentrate instead of leachate. The findings showed that volatile solids (VS) removals were changed from 32% to 61% in the reactors. While the reactor of leachate+RO concentrate+OFMSW (C6) had the highest VS removal, the reactor of the sole substrate leachate had the lowest VS removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Comparison of Fission Power System Options for Lunar and Mars Surface Applications

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2006-01-01

This paper presents a comparison of reactor and power conversion design options for 50 kWe class lunar and Mars surface power applications with scaling from 25 to 200 kWe. Design concepts and integration approaches are provided for three reactor-converter combinations: gas-cooled Brayton, liquid-metal Stirling, and liquid-metal thermoelectric. The study examines the mass and performance of low temperature, stainless steel based reactors and higher temperature refractory reactors. The preferred system implementation approach uses crew-assisted assembly and in-situ radiation shielding via installation of the reactor in an excavated hole. As an alternative, self-deployable system concepts that use earth-delivered, on-board radiation shielding are evaluated. The analyses indicate that among the 50 kWe stainless steel reactor options, the liquid-metal Stirling system provides the lowest mass at about 5300 kg followed by the gas-cooled Brayton at 5700 kg and the liquid-metal thermoelectric at 8400 kg. The use of a higher temperature, refractory reactor favors the gas-cooled Brayton option with a system mass of about 4200 kg as compared to the Stirling and thermoelectric options at 4700 and 5600 kg, respectively. The self-deployed concepts with on-board shielding result in a factor of two system mass increase as compared to the in-situ shielded concepts.

Metabolic modeling of synthesis gas fermentation in bubble column reactors.

PubMed

Chen, Jin; Gomez, Jose A; Höffner, Kai; Barton, Paul I; Henson, Michael A

2015-01-01

A promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. While commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. We developed and evaluated a spatiotemporal metabolic model for bubble column reactors with the syngas fermenting bacterium Clostridium ljungdahlii as the microbial catalyst. Our modeling approach involved combining a genome-scale reconstruction of C. ljungdahlii metabolism with multiphase transport equations that govern convective and dispersive processes within the spatially varying column. The reactor model was spatially discretized to yield a large set of ordinary differential equations (ODEs) in time with embedded linear programs (LPs) and solved using the MATLAB based code DFBAlab. Simulations were performed to analyze the effects of important process and cellular parameters on key measures of reactor performance including ethanol titer, ethanol-to-acetate ratio, and CO and H2 conversions. Our computational study demonstrated that mathematical modeling provides a complementary tool to experimentation for understanding, predicting, and optimizing syngas fermentation reactors. These model predictions could guide future cellular and process engineering efforts aimed at alleviating bottlenecks to biochemical production in syngas bubble column reactors.

Study of parameters affecting the conversion in a plug flow reactor for reactions of the type 2A→B

NASA Astrophysics Data System (ADS)

Beltran-Prieto, Juan Carlos; Long, Nguyen Huynh Bach Son

2018-04-01

Modeling of chemical reactors is an important tool to quantify reagent conversion, product yield and selectivity towards a specific compound and to describe the behavior of the system. Proposal of differential equations describing the mass and energy balance are among the most important steps required during the modeling process as they play a special role in the design and operation of the reactor. Parameters governing transfer of heat and mass have a strong relevance in the rate of the reaction. Understanding this information is important for the selection of reactor and operating regime. In this paper we studied the irreversible gas-phase reaction 2A→B. We model the conversion that can be achieved as function of the reactor volume and feeding temperature. Additionally, we discuss the effect of activation energy and the heat of reaction on the conversion achieved in the tubular reactor. Furthermore, we considered that dimerization occurs instantaneously in the catalytic surface to develop equations for the determination of rate of reaction per unit area of three different catalytic surface shapes. This data can be combined with information about the global rate of conversion in the reactor to improve regent conversion and yield of product.

Anaerobic reactor/high rate pond combined technology for sewage treatment in the Mediterranean area.

PubMed

El Hafiane, F; El Hamouri, B

2005-01-01

Two high-rate, anaerobic/aerobic units were used to treat the sewage of the Institut Agronomique st Vétérinaire Hassan II (Morocco) campus in a 1,100 m2-plant designed for 1,500 e.p. and receiving 63 m3 per day. The anaerobic pre-treatment consisted of a two-step up-flow anaerobic reactor (TSUAR) comprising two reactors and one external settler all in series. The aerobic line, or post-treatment, consisted of a high-rate algal pond (HRAP) and one maturation pond in series. The system totalized a hydraulic retention time (HRT) of 9 days. A gravel filter (GF) was constructed behind the TSUAR to trap low-density particles. The TSUAR removed 80% of COD and 90% of SS within 48 h. Solids retention time in the reactors averaged 32 d with a specific sludge production of 0.28 g SS g(-1) COD removed. Almost 93% of the sludge evacuated from the settler was stabilized. Specific biogas production from both reactors was 0.25m3 kg(-1) COD removed. Used in this configuration, the HRAP lost its BOD removal activity and increased its nutrients and pathogens removal capabilities (tertiary treatment). Results showed that 85% of total nitrogen and 48% of total phosphorus were removed by the HRAP. Land area requirement of this combination was less than 1 m2 per capita and filtered final effluent was of excellent quality (COD, 82 mg/l; TKN, 8.3 mg/l; total P, 2.7 mg/l, faecal coliforms, 2.4 10(3)/100 ml and zero helminths eggs).

SP-100 reactor with Brayton conversion for lunar surface applications

NASA Technical Reports Server (NTRS)

Mason, Lee S.; Rodriguez, Carlos D.; Mckissock, Barbara I.; Hanlon, James C.; Mansfield, Brian C.

1992-01-01

Examined here is the potential for integrating Brayton-cycle power conversion with the SP-100 reactor for lunar surface power system applications. Two designs were characterized and modeled. The first design integrates a 100-kWe SP-100 Brayton power system with a lunar lander. This system is intended to meet early lunar mission power needs while minimizing on-site installation requirements. Man-rated radiation protection is provided by an integral multilayer, cylindrical lithium hydride/tungsten (LiH/W) shield encircling the reactor vessel. Design emphasis is on ease of deployment, safety, and reliability, while utilizing relatively near-term technology. The second design combines Brayton conversion with the SP-100 reactor in a erectable 550-kWe powerplant concept intended to satisfy later-phase lunar base power requirements. This system capitalizes on experience gained from operating the initial 100-kWe module and incorporates some technology improvements. For this system, the reactor is emplaced in a lunar regolith excavation to provide man-rated shielding, and the Brayton engines and radiators are mounted on the lunar surface and extend radially from the central reactor. Design emphasis is on performance, safety, long life, and operational flexibility.

X-ray digital industrial radiography (DIR) for local liquid velocity (VLL) measurement in trickle bed reactors (TBRs): Validation of the technique

NASA Astrophysics Data System (ADS)

Mohd Salleh, Khairul Anuar; Rahman, Mohd Fitri Abdul; Lee, Hyoung Koo; Al Dahhan, Muthanna H.

2014-06-01

Local liquid velocity measurements in Trickle Bed Reactors (TBRs) are one of the essential components in its hydrodynamic studies. These measurements are used to effectively determine a reactor's operating condition. This study was conducted to validate a newly developed technique that combines Digital Industrial Radiography (DIR) with Particle Tracking Velocimetry (PTV) to measure the Local Liquid Velocity (VLL) inside TBRs. Three millimeter-sized Expanded Polystyrene (EPS) beads were used as packing material. Three validation procedures were designed to test the newly developed technique. All procedures and statistical approaches provided strong evidence that the technique can be used to measure the VLL within TBRs.

Fast breeder reactor protection system

DOEpatents

van Erp, J.B.

1973-10-01

Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

Fluidized bed coal combustion reactor

NASA Technical Reports Server (NTRS)

Moynihan, P. I.; Young, D. L. (Inventor)

1981-01-01

A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

COMPOSITE NEUTRONIC REACTOR

DOEpatents

Menke, J.R.

1963-06-11

This patent relates to a reactor having a core which comprises an inner active region and an outer active region, each region separately having a k effective less than one and a k infinity greater than one. The inner and outer regions in combination have a k effective at least equal to one and each region contributes substantially to the k effective of the reactor core. The inner region has a low moderator to fuel ratio such that the majority of fissions occurring therein are induced by neutrons having energies greater than thermal. The outer region has a high moderator to fuel ratio such that the majority of fissions occurring therein are induced by thermal neutrons. (AEC)

Spherical torus fusion reactor

DOEpatents

Peng, Yueng-Kay M.

1989-04-04

A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

Spherical torus fusion reactor

DOEpatents

Peng, Yueng-Kay M.

1989-01-01

A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

X-ray digital industrial radiography (DIR) for local liquid velocity (V(LL)) measurement in trickle bed reactors (TBRs): validation of the technique.

PubMed

Mohd Salleh, Khairul Anuar; Rahman, Mohd Fitri Abdul; Lee, Hyoung Koo; Al Dahhan, Muthanna H

2014-06-01

Local liquid velocity measurements in Trickle Bed Reactors (TBRs) are one of the essential components in its hydrodynamic studies. These measurements are used to effectively determine a reactor's operating condition. This study was conducted to validate a newly developed technique that combines Digital Industrial Radiography (DIR) with Particle Tracking Velocimetry (PTV) to measure the Local Liquid Velocity (V(LL)) inside TBRs. Three millimeter-sized Expanded Polystyrene (EPS) beads were used as packing material. Three validation procedures were designed to test the newly developed technique. All procedures and statistical approaches provided strong evidence that the technique can be used to measure the V(LL) within TBRs.

Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor

DOEpatents

LeVert, Francis E.; Cox, Samson A.

1978-01-01

A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power level of the reactor.

PRELIMINARY HAZARDS SUMMARY REPORT FOR THE VALLECITOS SUPERHEAT REACTOR

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

Murray, J.L.

1961-02-01

BS>The Vallecitos Superheat Reactor (VSR) is a light-watermoderated, thermal-spectrum reactor, cooled by a combination of moderator boiling and forced convection cooling with saturated steam. The reactor core consists of 32 fuel hurdles containing 5300 lb of UO/sub 2/ enriched in U/sub 235/ to 3.6%. The fuel elements are arranged in individual process tubes that direct the cooling steam flow and separate the steam from the water moderator. The reactor vessel is designed for 1250 psig and operates at 960 to 1000 psig. With the reactor operating at 12.5 Mw(t), the maximum fuel cladding temperature is 1250 deg F and themore » cooling steam is superheated to an average temperature of about 810 deg F at 905 psig. Nu clear operation of the reactor is controlled by 12 control rods, actuated by drives mounted on the bottom of the reactor vessel. The water moderator recirculates inside the reactor vessel and through the core region by natural convection. Inherent safety features of the reactor include the negative core reactivity effects upon heating the UO/sub 2/ fuel (Doppler effect), upon increasing the temperature or void content of the moderator in the operating condition, and upon unflooding the fuel process tubes in the hot condition. Snfety features designed into the reactor and plant systems include a system of sensors and devices to detect petentially unsafe operating conditions and to initiate automatically the appropriate countermeasures, a set of fast and reliable control rods for scramming the reactor if a potentially unsafe condition occurs, a manually-actuated liquid neutron poison system, and an emergency cooling system to provide continued steam flow through the reactor core in the event the reactor becomes isolated from either its normal source of steam supply or discharge. The release of radioactivity to unrestricted areas is maintained within permissible limits by monitoring the radioactivity of wastes and controlling their release. The reactor and many of its auxiliaries are housed within a high-integrity essentially leak-tight containment vessel. (auth)« less

Repetition rates in heavy ion beam driven fusion reactors

NASA Astrophysics Data System (ADS)

Peterson, Robert R.

1986-01-01

The limits on the cavity gas density required for beam propagation and condensation times for material vaporized by target explosions can determine the maximum repetition rate of Heavy Ion Beam (HIB) driven fusion reactors. If the ions are ballistically focused onto the target, the cavity gas must have a density below roughly 10-4 torr (3×1012 cm-3) at the time of propagation; other propagation schemes may allow densities as high as 1 torr or more. In some reactor designs, several kilograms of material may be vaporized off of the target chamber walls by the target generated x-rays, raising the average density in the cavity to 100 tor or more. A one-dimensional combined radiation hydrodynamics and vaporization and condensation computer code has been used to simulate the behavior of the vaporized material in the target chambers of HIB fusion reactors.

National Environmental Policy Act Hazards Assessment for the TREAT Alternative

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

Boyd D. Christensen; Annette L. Schafer

2013-11-01

This document provides an assessment of hazards as required by the National Environmental Policy Act for the alternative of restarting the reactor at the Transient Reactor Test (TREAT) facility by the Resumption of Transient Testing Program. Potential hazards have been identified and screening level calculations have been conducted to provide estimates of unmitigated dose consequences that could be incurred through this alternative. Consequences considered include those related to use of the TREAT Reactor, experiment assembly handling, and combined events involving both the reactor and experiments. In addition, potential safety structures, systems, and components for processes associated with operating TREAT andmore » onsite handling of nuclear fuels and experiments are listed. If this alternative is selected, a safety basis will be prepared in accordance with 10 CFR 830, “Nuclear Safety Management,” Subpart B, “Safety Basis Requirements.”« less

National Environmental Policy Act Hazards Assessment for the TREAT Alternative

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

Christensen, Boyd D.; Schafer, Annette L.

2014-02-01

This document provides an assessment of hazards as required by the National Environmental Policy Act for the alternative of restarting the reactor at the Transient Reactor Test (TREAT) facility by the Resumption of Transient Testing Program. Potential hazards have been identified and screening level calculations have been conducted to provide estimates of unmitigated dose consequences that could be incurred through this alternative. Consequences considered include those related to use of the TREAT Reactor, experiment assembly handling, and combined events involving both the reactor and experiments. In addition, potential safety structures, systems, and components for processes associated with operating TREAT andmore » onsite handling of nuclear fuels and experiments are listed. If this alternative is selected, a safety basis will be prepared in accordance with 10 CFR 830, “Nuclear Safety Management,” Subpart B, “Safety Basis Requirements.”« less

IBD Selection for the 288kg Prototype SoLid Module

NASA Astrophysics Data System (ADS)

Saunders, D.; SoLid Collaboration

2017-09-01

The SoLid experiment aims to make a measurement of very short baseline neutrino oscillations using reactor antineutrinos. Key to its sensitivity are the experiment’s high spatial and energy resolution, combined with a very suitable reactor source and excellent background rejection. Placed on the surface at just 5 m from the reactor core, the cosmic flux and reactor output lead to a challenging environment. The fine segmentation of the detector, 5 cm cubes, allows the topology of events to be studied to previously unseen precision. This offers new and unexplored handles for tackling these backgrounds - a key requirement for SoLid physics aims. Using the most recent SoLid prototype (288 kg, 20% scale), we present the first selection to focus on IBD signals. This includes descriptions of SoLid signals and backgrounds, and demonstration that the segmentation can lead to gains in orders of magnitude in background rejection.

Method and apparatus for a catalytic firebox reactor

DOEpatents

Smith, Lance L.; Etemad, Shahrokh; Ulkarim, Hasan; Castaldi, Marco J.; Pfefferle, William C.

2001-01-01

A catalytic firebox reactor employing an exothermic catalytic reaction channel and multiple cooling conduits for creating a partially reacted fuel/oxidant mixture. An oxidation catalyst is deposited on the walls forming the boundary between the multiple cooling conduits and the exothermic catalytic reaction channel, on the side of the walls facing the exothermic catalytic reaction channel. This configuration allows the oxidation catalyst to be backside cooled by any fluid passing through the cooling conduits. The heat of reaction is added to both the fluid in the exothermic catalytic reaction channel and the fluid passing through the cooling conduits. After discharge of the fluids from the exothermic catalytic reaction channel, the fluids mix to create a single combined flow. A further innovation in the reactor incorporates geometric changes in the exothermic catalytic reaction channel to provide streamwise variation of the velocity of the fluids in the reactor.

Interaction between control and design of a SHARON reactor: economic considerations in a plant-wide (BSM2) context.

PubMed

Volcke, E I P; van Loosdrecht, M C M; Vanrolleghem, P A

2007-01-01

The combined SHARON-Anammox process is a promising technique for nitrogen removal from wastewater streams with high ammonium concentrations. It is typically applied to sludge digestion reject water, in order to relieve the activated sludge tanks, to which this stream is typically recycled. This contribution assesses the impact of the applied control strategy in the SHARON-reactor, both on the effluent quality of the subsequent Anammox reactor as well as on the plant-wide level by means of an operating cost index. Moreover, it is investigated to which extent the usefulness of a certain control strategy depends on the reactor design (volume). A simulation study is carried out using the plant-wide Benchmark Simulation Model no. 2 (BSM2), extended with the SHARON and Anammox processes. The results reveal a discrepancy between optimizing the reject water treatment performance and minimizing plant-wide operating costs.

Flow instability in particle-bed nuclear reactors

NASA Technical Reports Server (NTRS)

Kerrebrock, J. L.; Kalamas, J.

1993-01-01

A three-dimensional model of the stability of the particle-bed reactor is presented, in which the fluid has mobility in three dimensions. The model accurately represents the stability at low Re numbers as well as the effects of the cold and hot frits and of the heat conduction and radiation in the particle bed. The model can be easily extended to apply to the cylindrical geometry of particle-bed reactors. Exemplary calculations are carried out, showing that a particle bed without a cold frit would be subject to instability if operated at the high-temperature ratios used for nuclear rockets and at power densities below about 4 MW/l; since the desired power density for such a reactor is about 40 MW/l, the operation at design exit temperature but at reduced power could be hazardous. Calculations show however that it might be possible to remove the instability problem by appropriate combinations of cold and hot frits.

A feasibility assessment of installation, operation and disposal options for nuclear reactor power system concepts for a NASA growth space station

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.; Heller, Jack A.

1987-01-01

A preliminary feasibility assessment of the integration of reactor power system concepts with a projected growth space station architecture was conducted to address a variety of installation, operational disposition, and safety issues. A previous NASA sponsored study, which showed the advantages of space station - attached concepts, served as the basis for this study. A study methodology was defined and implemented to assess compatible combinations of reactor power installation concepts, disposal destinations, and propulsion methods. Three installation concepts that met a set of integration criteria were characterized from a configuration and operational viewpoint, with end-of-life disposal mass identified. Disposal destinations that met current aerospace nuclear safety criteria were identified and characterized from an operational and energy requirements viewpoint, with delta-V energy requirement as a key parameter. Chemical propulsion methods that met current and near-term application criteria were identified and payload mass and delta-V capabilities were characterized. These capabilities were matched against concept disposal mass and destination delta-V requirements to provide the feasibility of each combination.

Integrating anammox with the autotrophic denitrification process via electrochemistry technology.

PubMed

Qiao, Sen; Yin, Xin; Zhou, Jiti; Wei, Li'e; Zhong, Jiayou

2018-03-01

In this study, an autotrophic denitrification process was successfully coupled with anammox to remove the nitrate by-product via electrochemical technology. When the voltage applied to the combined electrode reactor was 1.5 V, the electrode reaction removed nitrate by using the autotrophic denitrification biomass without affecting the anammox biomass. The nitrogen removal efficiency of the combined electrode reactor reached 99.1% without detectable nitrate at an influent NO 2 - -N/NH 4 + -N ratio of 1.5. On day 223, using the model calculations based on reaction equations, 19.7% of total nitrogen was removed via the autotrophic denitrification process, while the majority of nitrogen removal (approximately 79.4%) was attributed to the anammox reaction. Small variations of the population numbers and community structure of artificial bacteria according to electron microscopy predicted that the anammox and autotrophic denitrifying biomasses could coexist in the electrode reactor. Then, 16S rRNA analysis determined that the anammox biomass group was always dominant in mixed flora during continuous cultivation. Copyright © 2017 Elsevier Ltd. All rights reserved.

A feasibility assessment of nuclear reactor power system concepts for the NASA Growth Space Station

NASA Technical Reports Server (NTRS)

Bloomfield, H. S.; Heller, J. A.

1986-01-01

A preliminary feasibility assessment of the integration of reactor power system concepts with a projected growth Space Station architecture was conducted to address a variety of installation, operational, disposition and safety issues. A previous NASA sponsored study, which showed the advantages of Space Station - attached concepts, served as the basis for this study. A study methodology was defined and implemented to assess compatible combinations of reactor power installation concepts, disposal destinations, and propulsion methods. Three installation concepts that met a set of integration criteria were characterized from a configuration and operational viewpoint, with end-of-life disposal mass identified. Disposal destinations that met current aerospace nuclear safety criteria were identified and characterized from an operational and energy requirements viewpoint, with delta-V energy requirement as a key parameter. Chemical propulsion methods that met current and near-term application criteria were identified and payload mass and delta-V capabilities were characterized. These capabilities were matched against concept disposal mass and destination delta-V requirements to provide a feasibility of each combination.

Enhanced anaerobic digestion performance via combined solids- and leachate-based hydrolysis reactor inoculation.

PubMed

Wilson, L Paige; Sharvelle, Sybil E; De Long, Susan K

2016-11-01

Suboptimal conditions in anaerobic digesters (e.g., presence of common inhibitors ammonia and salinity) limit waste hydrolysis and lead to unstable performance and process failures. Application of inhibitor-tolerant inocula improves hydrolysis, but approaches are needed to establish and maintain these desired waste-hydrolyzing bacteria in high-solids reactors. Herein, performance was compared for leach bed reactors (LBRs) seeded with unacclimated or acclimated inoculum (0-60% by mass) at start-up and over long-term operation. High quantities of inoculum (∼60%) increase waste hydrolysis and are beneficial at start-up or when inhibitors are increasing. After start-up (∼112days) with high inoculum quantities, leachate recirculation leads to accumulation of inhibitor-tolerant hydrolyzing bacteria in leachate. During long-term operation, low inoculum quantities (∼10%) effectively increase waste hydrolysis relative to without solids-derived inoculum. Molecular analyses indicated that combining digested solids with leachate-based inoculum doubles quantities of Bacteria contacting waste over a batch and supplies additional desirable phylotypes Bacteriodes and Clostridia. Copyright © 2016 Elsevier Ltd. All rights reserved.

Submersion criticality safety of tungsten-rhenium urania cermet fuel for space propulsion and power applications

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

A.E. Craft; R. C. O'Brien; S. D. Howe

Nuclear thermal rockets are the preferred propulsion technology for a manned mission to Mars, and tungsten–uranium oxide cermet fuels could provide significant performance and cost advantages for nuclear thermal rockets. A nuclear reactor intended for use in space must remain subcritical before and during launch, and must remain subcritical in launch abort scenarios where the reactor falls back to Earth and becomes submerged in terrestrial materials (including seawater, wet sand, or dry sand). Submersion increases reflection of neutrons and also thermalizes the neutron spectrum, which typically increases the reactivity of the core. This effect is typically very significant for compact,more » fast-spectrum reactors. This paper provides a submersion criticality safety analysis for a representative tungsten/uranium oxide fueled reactor with a range of fuel compositions. Each submersion case considers both the rhenium content in the matrix alloy and the uranium oxide volume fraction in the cermet. The inclusion of rhenium significantly improves the submersion criticality safety of the reactor. While increased uranium oxide content increases the reactivity of the core, it does not significantly affect the submersion behavior of the reactor. There is no significant difference in submersion behavior between reactors with rhenium distributed within the cermet matrix and reactors with a rhenium clad in the coolant channels. The combination of the flooding of the coolant channels in submersion scenarios and the presence of a significant amount of spectral shift absorbers (i.e. high rhenium concentration) further decreases reactivity for short reactor cores compared to longer cores.« less

Burning high-level TRU waste in fusion fission reactors

NASA Astrophysics Data System (ADS)

Shen, Yaosong

2016-09-01

Recently, the concept of actinide burning instead of a once-through fuel cycle for disposing spent nuclear fuel seems to get much more attention. A new method of burning high-level transuranic (TRU) waste combined with Thorium-Uranium (Th-U) fuel in the subcritical reactors driven by external fusion neutron sources is proposed in this paper. The thorium-based TRU fuel burns all of the long-lived actinides via a hard neutron spectrum while outputting power. A one-dimensional model of the reactor concept was built by means of the ONESN_BURN code with new data libraries. The numerical results included actinide radioactivity, biological hazard potential, and much higher burnup rate of high-level transuranic waste. The comparison of the fusion-fission reactor with the thermal reactor shows that the harder neutron spectrum is more efficient than the soft. The Th-U cycle produces less TRU, less radiotoxicity and fewer long-lived actinides. The Th-U cycle provides breeding of 233U with a long operation time (>20 years), hence significantly reducing the reactivity swing while improving safety and burnup.

Method for continuously recovering metals using a dual zone chemical reactor

DOEpatents

Bronson, M.C.

1995-02-14

A dual zone chemical reactor continuously processes metal-containing materials while regenerating and circulating a liquid carrier. The starting materials are fed into a first reaction zone of a vessel containing a molten salt carrier. The starting materials react to form a metal product and a by-product that dissolves in the molten salt that flows to a second reaction zone in the reaction vessel. The second reaction zone is partitioned from, but in fluid communication with, the first reaction zone. The liquid carrier continuously circulates along a pathway between the first reaction zone and the second reaction zone. A reactive gas is introduced into the second reaction zone to react with the reaction by-product to generate the molten salt. The metal product, the gaseous waste products, and the excess liquid carrier are removed without interrupting the operation of the reactor. The design of the dual zone reactor can be adapted to combine a plurality of liquid carrier regeneration zones in a multiple dual zone chemical reactor for production scale processing. 6 figs.

Texture and hydride orientation relationship of Zircaloy-4 fuel clad tube during its fabrication for pressurized heavy water reactors

NASA Astrophysics Data System (ADS)

Vaibhaw, Kumar; Rao, S. V. R.; Jha, S. K.; Saibaba, N.; Jayaraj, R. N.

2008-12-01

Zircaloy-4 material is used for cladding tube in pressurized heavy water reactors (PHWRs) of 220 MWe and 540 MWe capacity in India. These tubes are fabricated by using various combinations of thermo-mechanical processes to achieve desired mechanical and corrosion properties. Cladding tube develops crystallographic texture during its fabrication, which has significant influence on its in-reactor performance. Due to radiolytic decomposition of water Zircaloy-4 picks-up hydrogen. This hydrogen in excess of its maximum solubility in reactor operating condition (˜300 °C), precipitates as zirconium hydrides causing embrittlement of cladding tube. Hydride orientation in the radial direction of the tube limits the service life and lowers the fuel burn-up in reactor. The orientation of the hydride primarily depends on texture developed during fabrication. A correlation between hydride orientation ( F n) with the texture in the tube during its fabrication has been developed using a second order polynomial. The present work is aimed at quantification and correlation of texture evolved in Zircaloy-4 cladding tube using Kearn's f-parameter during its fabrication process.

KERENA safety concept in the context of the Fukushima accident

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

Zacharias, T.; Novotny, C.; Bielor, E.

Within the last three years AREVA NP and E.On KK finalized the basic design of KERENA which is a medium sized innovative boiling water reactor, based on the operational experience of German BWR nuclear power plants (NPPs). It is a generation III reactor design with a net electrical output of about 1250 MW. It combines active safety equipment of service-proven designs with new passive safety components, both safety classified. The passive systems utilize basic laws of physics, such as gravity and natural convection, enabling them to function without electric power. Even actuation of these systems is performed thanks to basicmore » physic laws. The degree of diversity in component and system design, achieved by combining active and passive equipment, results in a very low core damage frequency. The Fukushima accident enhanced the world wide discussion about the safety of operating nuclear power plants. World wide stress tests for operating nuclear power plants are being performed embracing both natural and man made hazards. Beside the assessment of existing power plants, also new designs are analyzed regarding the system response to beyond design base accidents. KERENA's optimal combination of diversified cooling systems (active and passive) allows passing efficiently such tests, with a high level of confidence. This paper describes the passive safety components and the KERENA reactor behavior after a Fukushima like accident. (authors)« less

Thermomechanics of candidate coatings for advanced gas reactor fuels

NASA Astrophysics Data System (ADS)

Nosek, A.; Conzen, J.; Doescher, H.; Martin, C.; Blanchard, J.

2007-09-01

Candidate fuel/coating combinations for an advanced, coated-fuel particle for a gas-cooled fast reactor (GFR) have been evaluated. These all-ceramic fuel forms consist of a fuel kernel made of UC or UN, surrounded with two shells (a buffer and a coating) made of TiC, SiC, ZrC, TiN, or ZrN. These carbides and nitrides are analyzed with finite element models to determine the stresses produced in the micro fuel particles from differential thermal expansion, fission gas release, swelling, and creep during particle fabrication and reactor operation. This study will help determine the feasibility of different fuel and coating combinations and identify the critical loads. The analysis shows that differential thermal expansion of the fuel and coating dictate the amount of stress for changing temperatures (such as during fabrication), and that the coating creep is able to mitigate an otherwise overwhelming amount of stress from fuel swelling. Because fracture is a likely mode of failure, a fracture mechanics study is also included to identify the relative likelihood of catastrophic fracture of the coating and resulting gas release. Overall, the analysis predicts that UN/ZrC is the best thermomechanical fuel/coating combination for mitigating the stress within the new fuel particle, but UN/TiN and UN/ZrN could also be strong candidates if their unknown creep rates are sufficiently large.

Nuclear reactor melt-retention structure to mitigate direct containment heating

DOEpatents

Tutu, Narinder K.; Ginsberg, Theodore; Klages, John R.

1991-01-01

A light water nuclear reactor melt-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten core material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the melt-retention chamber there is provided a passageway that includes molten core droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten core droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the melt-retention structure to direct the flow of molten core material and help retain it within the melt-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the melt-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten core droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.

Integrated Decision-Making Tool to Develop Spent Fuel Strategies for Research Reactors

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

Beatty, Randy L; Harrison, Thomas J

IAEA Member States operating or having previously operated a Research Reactor are responsible for the safe and sustainable management and disposal of associated radioactive waste, including research reactor spent nuclear fuel (RRSNF). This includes the safe disposal of RRSNF or the corresponding equivalent waste returned after spent fuel reprocessing. One key challenge to developing general recommendations lies in the diversity of spent fuel types, locations and national/regional circumstances rather than mass or volume alone. This is especially true given that RRSNF inventories are relatively small, and research reactors are rarely operated at a high power level or duration typical ofmore » commercial power plants. Presently, many countries lack an effective long-term policy for managing RRSNF. This paper presents results of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) #T33001 on Options and Technologies for Managing the Back End of the Research Reactor Nuclear Fuel Cycle which includes an Integrated Decision Making Tool called BRIDE (Back-end Research reactor Integrated Decision Evaluation). This is a multi-attribute decision-making tool that combines the Total Estimated Cost of each life-cycle scenario with Non-economic factors such as public acceptance, technical maturity etc and ranks optional back-end scenarios specific to member states situations in order to develop a specific member state strategic plan with a preferred or recommended option for managing spent fuel from Research Reactors.« less

Adsorption of Streptococcus faecalis on diatomite carriers for use in biotransformations.

PubMed

Anderson, W A; Bay, P; Legge, R L; Moo-Young, M

1990-01-01

Adsorption of cells on particulate carriers is potentially one of the most cost-effective immobilization techniques available. Diatomite carriers, such as Celite, have desirable physical properties, are inexpensive, and are suitable for both mycelial and bacterial systems. This work investigated the use of diatomite carriers as a biocatalyst support in a packed-bed reactor where L-tyrosine was enzymatically decarboxylated using adsorbed, non-growing cells of Streptococcus faecalis. Composition of microbial adsorption on different Celite types, with mean pore sizes ranging from 0.55 to 22 microns, showed there was no significant difference in biomass loading capacity under the conditions used. Using Celite 560, biomass loadings in a packed-bed reactor varied from 10 to 30 g dm-3 of reactor volume, which compares favourably with other adsorption methods. When used to decarboxylate L-tyrosine, the reactor was found to have a half-life of 15-20 h. A combination of enzyme activity loss and slow leakage of biomass from the packed-bed reactor was responsible for the decline in conversion. Treatment of the S. faecalis cells with glutaraldehyde significantly reduced the enzyme activity loss and extended the reactor half-life to 65 h, but had little effect on the rate of cell leakage from the reactor. Further work on reduction of cell leakage rate seems necessary for evaluation of the system's practicality.

Optimal Refueling Pattern Search for a CANDU Reactor Using a Genetic Algorithm

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

Quang Binh, DO; Gyuhong, ROH; Hangbok, CHOI

2006-07-01

This paper presents the results from the application of genetic algorithms to a refueling optimization of a Canada deuterium uranium (CANDU) reactor. This work aims at making a mathematical model of the refueling optimization problem including the objective function and constraints and developing a method based on genetic algorithms to solve the problem. The model of the optimization problem and the proposed method comply with the key features of the refueling strategy of the CANDU reactor which adopts an on-power refueling operation. In this study, a genetic algorithm combined with an elitism strategy was used to automatically search for themore » refueling patterns. The objective of the optimization was to maximize the discharge burn-up of the refueling bundles, minimize the maximum channel power, or minimize the maximum change in the zone controller unit (ZCU) water levels. A combination of these objectives was also investigated. The constraints include the discharge burn-up, maximum channel power, maximum bundle power, channel power peaking factor and the ZCU water level. A refueling pattern that represents the refueling rate and channels was coded by a one-dimensional binary chromosome, which is a string of binary numbers 0 and 1. A computer program was developed in FORTRAN 90 running on an HP 9000 workstation to conduct the search for the optimal refueling patterns for a CANDU reactor at the equilibrium state. The results showed that it was possible to apply genetic algorithms to automatically search for the refueling channels of the CANDU reactor. The optimal refueling patterns were compared with the solutions obtained from the AUTOREFUEL program and the results were consistent with each other. (authors)« less

CONTROL CONSOLE FOR MTR FISSION PRODUCT MONITOR, USED TO DETECT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CONTROL CONSOLE FOR MTR FISSION PRODUCT MONITOR, USED TO DETECT BREAKS IN CLADDING OF FUEL ELEMENTS. COUNT-RATE METER IN TOP PANEL INDICATES AMOUNT OF RADIOACTIVITY. LOWER PANELS SUPPLY POWER AND AMPLIFICATION OF SIGNALS GENERATED BY SCINTILLATION COUNTER/PHOTOMULTIPLIER TUBE COMBINATION IN RESPONSE TO RADIOACTIVITY IN A SAMPLE OF THE COOLING WATER. INL NEGATIVE NO. 56-771. Jack L. Anderson, Photographer, 3/15/1956. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

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

Mohanty, Subhasish; Majumdar, Saurindranath

Irradiation creep plays a major role in the structural integrity of the graphite components in high temperature gas cooled reactors. Finite element procedures combined with a suitable irradiation creep model can be used to simulate the time-integrated structural integrity of complex shapes, such as the reactor core graphite reflector and fuel bricks. In the present work a comparative study was undertaken to understand the effect of linear and nonlinear irradiation creep on results of finite element based stress analysis. Numerical results were generated through finite element simulations of a typical graphite reflector.

Accelerated Irradiations for High Dose Microstructures in Fast Reactor Alloys

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

Jiao, Zhijie

The objective of this project is to determine the extent to which high dose rate, self-ion irradiation can be used as an accelerated irradiation tool to understand microstructure evolution at high doses and temperatures relevant to advanced fast reactors. We will accomplish the goal by evaluating phase stability and swelling of F-M alloys relevant to SFR systems at very high dose by combining experiment and modeling in an effort to obtain a quantitative description of the processes at high and low damage rates.

Long-term effects of operating temperature and sulphate addition on the methanogenic community structure of anaerobic hybrid reactors.

PubMed

Pender, Seán; Toomey, Margaret; Carton, Micheál; Eardly, Dónal; Patching, John W; Colleran, Emer; O'Flaherty, Vincent

2004-02-01

The diversity, population dynamics, and activity profiles of methanogens in anaerobic granular sludges from two anaerobic hybrid reactors treating a molasses wastewater both mesophilically (37 degrees C) and thermophilically (55 degrees C) during a 1081 day trial were determined. The influent to one of the reactors was supplemented with sulphate, after an acclimation period of 112 days, to determine the effect of competition with sulphate-reducing bacteria on the methanogenic community structure. Sludge samples were removed from the reactors at intervals throughout the operational period and examined by amplified ribosomal DNA (rDNA) restriction analysis (ARDRA) and partial sequencing of 16S rRNA genes. In total, 18 operational taxonomic units (OTUs) were identified, 12 of which were sequenced. The methanogenic communities in both reactors changed during the operational period. The seed sludge and the reactor biomass sampled during mesophilic operation, both in the presence and absence of sulphate, was characterised by a predominance of Methanosaeta spp. Following temperature elevation, the dominant methanogenic sequences detected in the non-sulphate supplemented reactor were closely related to Methanocorpusculum parvum. By contrast, the dominant OTUs detected in the sulphate-supplemented reactor upon temperature increase were related to the hydrogen-utilising methanogen, Methanobacterium thermoautotrophicum. The observed methanogenic community structure in the reactors correlated with the operational performance of the reactors during the trial and with physiological measurements of the reactor biomass. Both reactors achieved chemical oxygen demand (COD) removal efficiencies of over 90% during mesophilic operation, with or without sulphate supplementation. During thermophilic operation, the presence of sulphate resulted in decreased reactor performance (effluent acetate concentrations of >3000 mg/l and biogas methane content of <25%). It was demonstrated that methanogenic conversion of acetate at 55 degrees C was extremely sensitive to inhibition by sulphide (50% inhibition at 8-17 mg/l unionised sulphide at pH 7.6-8.0), while the conversion of H(2)/CO(2) methanogenically was favoured. The combination of experiments carried out demonstrated the presence of specific methanogenic populations during periods of successful operational performance.

Microfluidic reactors for visible-light photocatalytic water purification assisted with thermolysis

PubMed Central

Wang, Ning; Tan, Furui; Wan, Li; Wu, Mengchun

2014-01-01

Photocatalytic water purification using visible light is under intense research in the hope to use sunlight efficiently, but the conventional bulk reactors are slow and complicated. This paper presents an integrated microfluidic planar reactor for visible-light photocatalysis with the merits of fine flow control, short reaction time, small sample volume, and long photocatalyst durability. One additional feature is that it enables one to use both the light and the heat energy of the light source simultaneously. The reactor consists of a BiVO4-coated glass as the substrate, a blank glass slide as the cover, and a UV-curable adhesive layer as the spacer and sealant. A blue light emitting diode panel (footprint 10 mm × 10 mm) is mounted on the microreactor to provide uniform irradiation over the whole reactor chamber, ensuring optimal utilization of the photons and easy adjustments of the light intensity and the reaction temperature. This microreactor may provide a versatile platform for studying the photocatalysis under combined conditions such as different temperatures, different light intensities, and different flow rates. Moreover, the microreactor demonstrates significant photodegradation with a reaction time of about 10 s, much shorter than typically a few hours using the bulk reactors, showing its potential as a rapid kit for characterization of photocatalyst performance. PMID:25584117

Reactor on-off antineutrino measurement with KamLAND

NASA Astrophysics Data System (ADS)

Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, H.; Koga, M.; Matsuda, R.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obata, A.; Oki, A.; Oki, Y.; Otani, M.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yamada, S.; Yamauchi, Y.; Yoshida, H.; Kozlov, A.; Yoshida, S.; Piepke, A.; Banks, T. I.; Fujikawa, B. K.; Han, K.; O'Donnell, T.; Berger, B. E.; Learned, J. G.; Matsuno, S.; Sakai, M.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

2013-08-01

The recent long-term shutdown of Japanese nuclear reactors has resulted in a significantly reduced reactor ν¯e flux at KamLAND. This running condition provides a unique opportunity to confirm and constrain backgrounds for the reactor ν¯e oscillation analysis. The data set also has improved sensitivity for other ν¯e signals, in particular ν¯e’s produced in β-decays from U238 and Th232 within the Earth’s interior, whose energy spectrum overlaps with that of reactor ν¯e’s. Including constraints on θ13 from accelerator and short-baseline reactor neutrino experiments, a combined three-flavor analysis of solar and KamLAND data gives fit values for the oscillation parameters of tan⁡2θ12=0.436-0.025+0.029, Δm212=7.53-0.18+0.18×10-5eV2, and sin⁡2θ13=0.023-0.002+0.002. Assuming a chondritic Th/U mass ratio, we obtain 116-27+28 ν¯e events from U238 and Th232, corresponding to a geo ν¯e flux of 3.4-0.8+0.8×106cm-2s-1 at the KamLAND location. We evaluate various bulk silicate Earth composition models using the observed geo ν¯e rate.

Thermally Simulated 32kW Direct-Drive Gas-Cooled Reactor: Design, Assembly, and Test

NASA Astrophysics Data System (ADS)

Godfroy, Thomas J.; Kapernick, Richard J.; Bragg-Sitton, Shannon M.

2004-02-01

One of the power systems under consideration for nuclear electric propulsion is a direct-drive gas-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the reactor to the Brayton system via a circulated closed loop gas. To allow early utilization, system designs must be relatively simple, easy to fabricate, and easy to test using non-nuclear heaters to closely mimic heat from fission. This combination of attributes will allow pre-prototypic systems to be designed, fabricated, and tested quickly and affordably. The ability to build and test units is key to the success of a nuclear program, especially if an early flight is desired. The ability to perform very realistic non-nuclear testing increases the success probability of the system. In addition, the technologies required by a concept will substantially impact the cost, time, and resources required to develop a successful space reactor power system. This paper describes design features, assembly, and test matrix for the testing of a thermally simulated 32kW direct-drive gas-cooled reactor in the Early Flight Fission - Test Facility (EFF-TF) at Marshall Space Flight Center. The reactor design and test matrix are provided by Los Alamos National Laboratories.

Pebble Bed Reactors Design Optimization Methods and their Application to the Pebble Bed Fluoride Salt Cooled High Temperature Reactor (PB-FHR)

NASA Astrophysics Data System (ADS)

Cisneros, Anselmo Tomas, Jr.

The Fluoride salt cooled High temperature Reactor (FHR) is a class of advanced nuclear reactors that combine the robust coated particle fuel form from high temperature gas cooled reactors, direct reactor auxillary cooling system (DRACS) passive decay removal of liquid metal fast reactors, and the transparent, high volumetric heat capacitance liquid fluoride salt working fluids---flibe (33%7Li2F-67%BeF)---from molten salt reactors. This combination of fuel and coolant enables FHRs to operate in a high-temperature low-pressure design space that has beneficial safety and economic implications. In 2012, UC Berkeley was charged with developing a pre-conceptual design of a commercial prototype FHR---the Pebble Bed- Fluoride Salt Cooled High Temperature Reactor (PB-FHR)---as part of the Nuclear Energy University Programs' (NEUP) integrated research project. The Mark 1 design of the PB-FHR (Mk1 PB-FHR) is 236 MWt flibe cooled pebble bed nuclear heat source that drives an open-air Brayton combine-cycle power conversion system. The PB-FHR's pebble bed consists of a 19.8% enriched uranium fuel core surrounded by an inert graphite pebble reflector that shields the outer solid graphite reflector, core barrel and reactor vessel. The fuel reaches an average burnup of 178000 MWt-d/MT. The Mk1 PB-FHR exhibits strong negative temperature reactivity feedback from the fuel, graphite moderator and the flibe coolant but a small positive temperature reactivity feedback of the inner reflector and from the outer graphite pebble reflector. A novel neutronics and depletion methodology---the multiple burnup state methodology was developed for an accurate and efficient search for the equilibrium composition of an arbitrary continuously refueled pebble bed reactor core. The Burnup Equilibrium Analysis Utility (BEAU) computer program was developed to implement this methodology. BEAU was successfully benchmarked against published results generated with existing equilibrium depletion codes VSOP and PEBBED for a high temperature gas cooled pebble bed reactor. Three parametric studies were performed for exploring the design space of the PB-FHR---to select a fuel design for the PB-FHR] to select a core configuration; and to optimize the PB-FHR design. These parametric studies investigated trends in the dependence of important reactor performance parameters such as burnup, temperature reactivity feedback, radiation damage, etc on the reactor design variables and attempted to understand the underlying reactor physics responsible for these trends. A pebble fuel parametric study determined that pebble fuel should be designed with a carbon to heavy metal ratio (C/HM) less than 400 to maintain negative coolant temperature reactivity coefficients. Seed and thorium blanket-, seed and inert pebble reflector- and seed only core configurations were investigated for annular FHR PBRs---the C/HM of the blanket pebbles and discharge burnup of the thorium blanket pebbles were additional design variable for core configurations with thorium blankets. Either a thorium blanket or graphite pebble reflector is required to shield the outer graphite reflector enough to extend its service lifetime to 60 EFPY. The fuel fabrication costs and long cycle lengths of the thorium blanket fuel limit the potential economic advantages of using a thorium blanket. Therefore, the seed and pebble reflector core configuration was adopted as the baseline core configuration. Multi-objective optimization with respect to economics was performed for the PB-FHR accounting for safety and other physical design constraints derived from the high-level safety regulatory criteria. These physical constraints were applied along in a design tool, Nuclear Application Value Estimator, that evaluated a simplified cash flow economics model based on estimates of reactor performance parameters calculated using correlations based on the results of parametric design studies for a specific PB-FHR design and a set of economic assumptions about the electricity market to evaluate the economic implications of design decisions. The optimal PB-FHR design---Mark 1 PB-FHR---is described along with a detailed summary of its performance characteristics including: the burnup, the burnup evolution, temperature reactivity coefficients, the power distribution, radiation damage distributions, control element worths, decay heat curves and tritium production rates. The Mk1 PB-FHR satisfies the PB-FHR safety criteria. The fuel, moderator (pebble core, pebble shell, graphite matrix, TRISO layers) and coolant have global negative temperature reactivity coefficients and the fuel temperatures are well within their limits.

Assessing the degree of plug flow in oxidation flow reactors (OFRs): a study on a potential aerosol mass (PAM) reactor

NASA Astrophysics Data System (ADS)

Mitroo, Dhruv; Sun, Yujian; Combest, Daniel P.; Kumar, Purushottam; Williams, Brent J.

2018-03-01

Oxidation flow reactors (OFRs) have been developed to achieve high degrees of oxidant exposures over relatively short space times (defined as the ratio of reactor volume to the volumetric flow rate). While, due to their increased use, attention has been paid to their ability to replicate realistic tropospheric reactions by modeling the chemistry inside the reactor, there is a desire to customize flow patterns. This work demonstrates the importance of decoupling tracer signal of the reactor from that of the tubing when experimentally obtaining these flow patterns. We modeled the residence time distributions (RTDs) inside the Washington University Potential Aerosol Mass (WU-PAM) reactor, an OFR, for a simple set of configurations by applying the tank-in-series (TIS) model, a one-parameter model, to a deconvolution algorithm. The value of the parameter, N, is close to unity for every case except one having the highest space time. Combined, the results suggest that volumetric flow rate affects mixing patterns more than use of our internals. We selected results from the simplest case, at 78 s space time with one inlet and one outlet, absent of baffles and spargers, and compared the experimental F curve to that of a computational fluid dynamics (CFD) simulation. The F curves, which represent the cumulative time spent in the reactor by flowing material, match reasonably well. We value that the use of a small aspect ratio reactor such as the WU-PAM reduces wall interactions; however sudden apertures introduce disturbances in the flow, and suggest applying the methodology of tracer testing described in this work to investigate RTDs in OFRs to observe the effect of modified inlets, outlets and use of internals prior to application (e.g., field deployment vs. laboratory study).

Treatment of fruit-juice industry wastewater in a two-stage anaerobic hybrid (AH) reactor system followed by a sequencing batch reactor (SBR).

PubMed

Tawfik, A; El-Kamah, H

2012-01-01

This study has been carried out to assess the performance of a combined system consisting of an anaerobic hybrid (AH) reactor followed by a sequencing batch reactor (SBR) for treatment of fruit-juice industry wastewater at a temperature of 26 degrees C. Three experimental runs were conducted in this investigation. In the first experiment, a single-stage AH reactor was operated at a hydraulic retention time (HRT) of 10.2 h and organic loading rate (OLR) of 11.8 kg COD m(-3) d(-1). The reactor achieved a removal efficiency of 42% for chemical oxygen demand (COD), 50.8% for biochemical oxygen demand (BOD5), 50.3% for volatile fatty acids (VFA) and 56.4% for total suspended solids (TSS). In the second experiment, two AH reactors connected in series achieved a higher removal efficiency for COD (67.4%), BOD5 (77%), and TSS (71.5%) at a total HRT of 20 h and an OLR of 5.9 kg COD m(-3) d(-1). For removal of the remaining portions of COD, BOD5 and TSS from the effluent of the two-stage AH system, a sequencing batch reactor (SBR) was investigated as a post-treatment unit. The reactor achieved a substantial reduction in total COD, resulting in an average effluent concentration of 50 mg L(-1) at an HRT of 11 h and OLR of 5.3 kg COD m(-3) d(-1). Almost complete removal of total BOD5 and oil and grease was achieved, i.e. 10 mg L(-1) and 1.2 mg L(-1), respectively, remained in the final effluent of the SBR.

Batch Tests To Determine Activity Distribution and Kinetic Parameters for Acetate Utilization in Expanded-Bed Anaerobic Reactors

PubMed Central

Fox, Peter; Suidan, Makram T.

1990-01-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (Ks) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for Ks. However, Ks was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of Ks on the effluent 3-ethylphenol concentration. A two-parameter search determined a Ks of 8.99 mg of acetate per liter and a Ki of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made. PMID:16348175

Batch tests to determine activity distribution and kinetic parameters for acetate utilization in expanded-bed anaerobic reactors.

PubMed

Fox, P; Suidan, M T

1990-04-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (K(s)) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for K(s). However, K(s) was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of K(s) on the effluent 3-ethylphenol concentration. A two-parameter search determined a K(s) of 8.99 mg of acetate per liter and a K(i) of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made.

Design test request No. 1263 K Reactor graphite key and VSR channel sleeve test

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

Kempf, F.J.

1964-12-10

The objectives of this test were: (1) Determine the coefficient of friction between two adjacent layers of K Reactor graphite at room temperature. (2) Determine the average load required to cause failure of an unirradiated K Reactor side reflector bar, when subjected to tensile loading applied through the reflector keys. (3) Determine the average load at failure and the average deflection at failure of a single VSR channel key when loaded in keyways with clearances equal to those used in original stack construction. (4) Determine the average load and deflection required to break the four K Reactor VSR keys whenmore » loaded simultaneously in both `3-layer` and `7-layer` mockups. Also determine the mode of key failure; i.e., shear, flexure or combined compression and bending. Following these key rupture tests, determine the strength and deflection characteristics of the proposed K Reactor VSR channel sleeve when loaded in a manner identical to that used to fracture the keys. (5) Determine the average load and deflection at failure of both the proposed K Reactor VSR channel sleeves and the proposed C Reactor sleeves when subjected to crushing loads. (6) Determine the extent of damage to the proposed K Reactor VSR channel sleeve when subjected to the following vertical rod loading conditions. (a) Full rod drop in a channel mockup which has been misaligned 2 1/2 inches. (b) Full rod drop in a channel which has been misaligned an amount equal to the maximum flexibility of a `universal` VSR.« less

Design and validation of an advanced entrained flow reactor system for studies of rapid solid biomass fuel particle conversion and ash formation reactions

NASA Astrophysics Data System (ADS)

Wagner, David R.; Holmgren, Per; Skoglund, Nils; Broström, Markus

2018-06-01

The design and validation of a newly commissioned entrained flow reactor is described in the present paper. The reactor was designed for advanced studies of fuel conversion and ash formation in powder flames, and the capabilities of the reactor were experimentally validated using two different solid biomass fuels. The drop tube geometry was equipped with a flat flame burner to heat and support the powder flame, optical access ports, a particle image velocimetry (PIV) system for in situ conversion monitoring, and probes for extraction of gases and particulate matter. A detailed description of the system is provided based on simulations and measurements, establishing the detailed temperature distribution and gas flow profiles. Mass balance closures of approximately 98% were achieved by combining gas analysis and particle extraction. Biomass fuel particles were successfully tracked using shadow imaging PIV, and the resulting data were used to determine the size, shape, velocity, and residence time of converting particles. Successful extractive sampling of coarse and fine particles during combustion while retaining their morphology was demonstrated, and it opens up for detailed time resolved studies of rapid ash transformation reactions; in the validation experiments, clear and systematic fractionation trends for K, Cl, S, and Si were observed for the two fuels tested. The combination of in situ access, accurate residence time estimations, and precise particle sampling for subsequent chemical analysis allows for a wide range of future studies, with implications and possibilities discussed in the paper.

Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

NASA Technical Reports Server (NTRS)

Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

2009-01-01

Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

Understanding the sorption and biotransformation of organic micropollutants in innovative biological wastewater treatment technologies.

PubMed

Alvarino, T; Suarez, S; Lema, J; Omil, F

2018-02-15

New technologies for wastewater treatment have been developed in the last years based on the combination of biological reactors operating under different redox conditions. Their efficiency in the removal of organic micropollutants (OMPs) has not been clearly assessed yet. This review paper is focussed on understanding the sorption and biotransformation of a selected group of 17 OMPs, including pharmaceuticals, hormones and personal care products, during biological wastewater treatment processes. Apart from considering the role of "classical" operational parameters, new factors such as biomass conformation and particle size, upward velocity applied or the addition of adsorbents have been considered. It has been found that the OMP removal by sorption not only depends on their physico-chemical characteristics and other parameters, such as the biomass conformation and particle size, or some operational conditions also relevant. Membrane biological reactors (MBR), have shown to enhance sorption and biotransformation of some OMPs. The same applies to technologies bases on direct addition of activated carbon in bioreactors. The OMP biotransformation degree and pathway is mainly driven by the redox potential and the primary substrate activity. The combination of different redox potentials in hybrid reactor systems can significantly enhance the overall OMP removal efficiency. Sorption and biotransformation can be synergistically promoted in biological reactors by the addition of activated carbon. The deeper knowledge of the main parameters influencing OMP removal provided by this review will allow optimizing the biological processes in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Bio-processing of copper from combined smelter dust and flotation concentrate: a comparative study on the stirred tank and airlift reactors.

PubMed

Vakylabad, Ali Behrad; Schaffie, Mahin; Ranjbar, Mohammad; Manafi, Zahra; Darezereshki, Esmaeel

2012-11-30

To scrutinize the influence of the design and type of the bioreactors on the bioleaching efficiency, the bioleaching were evaluated in a batch airlift and a batch stirred tank bioreactors with mixed mesophilic and mixed moderately thermophilic bacteria. According to the results, maximum copper recoveries were achieved using the cultures in the stirred tank bioreactors. It is worth noting that the main phase of the flotation concentrate was chalcopyrite (as a primary sulphide), but the smelter dust mainly contained secondary copper sulphides such as Cu(2)S, CuS, and Cu(5)FeS(4).Under optimum conditions, copper dissolution from the combined flotation concentrate and smelter dust (as an environmental hazard) reached 94.50% in the STR, and 88.02% in the airlift reactor with moderately thermophilic, after 23 days. Also, copper extractions calculated for the bioleaching using mesophilic bacteria were 48.73% and 37.19% in the STR (stirred tank reactor) and the airlift bioreactor, respectively. In addition, the SEM/EDS, XRD, chemical, and mineralogical analyses and studies confirmed the above results. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Taylor, Caitlin Anne; Bufford, Daniel Charles; Muntifering, Brittany Rana

Materials designed for nuclear reactors undergo microstructural changes resulting from a combination of several environmental factors, including neutron irradiation damage, gas accumulation and elevated temperatures. Typical ion beam irradiation experiments designed for simulating a neutron irradiation environment involve irradiating the sample with a single ion beam and subsequent characterization of the resulting microstructure, often by transmission electron microscopy (TEM). This method does not allow for examination of microstructural effects due to simultaneous gas accumulation and displacement cascade damage, which occurs in a reactor. Sandia’s in situ ion irradiation TEM (I 3TEM) offers the unique ability to observe microstructural changes duemore » to irradiation damage caused by concurrent multi-beam ion irradiation in real time. This allows for time-dependent microstructure analysis. A plethora of additional in situ stages can be coupled with these experiments, e.g., for more accurately simulating defect kinetics at elevated reactor temperatures. As a result, this work outlines experiments showing synergistic effects in Au using in situ ion irradiation with various combinations of helium, deuterium and Au ions, as well as some initial work on materials utilized in tritium-producing burnable absorber rods (TPBARs): zirconium alloys and LiAlO 2.« less

Multi-objective optimization of oxidative desulfurization in a sono-photochemical airlift reactor.

PubMed

Behin, Jamshid; Farhadian, Negin

2017-09-01

Response surface methodology (RSM) was employed to optimize ultrasound/ultraviolet-assisted oxidative desulfurization in an airlift reactor. Ultrasonic waves were incorporated in a novel-geometry reactor to investigate the synergistic effects of sono-chemistry and enhanced gas-liquid mass transfer. Non-hydrotreated kerosene containing sulfur and aromatic compounds was chosen as a case study. Experimental runs were conducted based on a face-centered central composite design and analyzed using RSM. The effects of two categorical factors, i.e., ultrasound and ultraviolet irradiation and two numerical factors, i.e., superficial gas velocity and oxidation time were investigated on two responses, i.e., desulfurization and de-aromatization yields. Two-factor interaction (2FI) polynomial model was developed for the responses and the desirability function associate with overlay graphs was applied to find optimum conditions. The results showed enhancement in desulfurization ability corresponds to more reduction in aromatic content of kerosene in each combination. Based on desirability approach and certain criteria considered for desulfurization/de-aromatization, the optimal desulfurization and de-aromatization yields of 91.7% and 48% were obtained in US/UV/O 3 /H 2 O 2 combination, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

A mechanism for proven technology foresight for emerging fast reactor designs and concepts

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

Anuar, Nuraslinda, E-mail: nuraslinda@uniten.edu.my; Muhamad Pauzi, Anas, E-mail: anas@uniten.edu.my

The assessment of emerging nuclear fast reactor designs and concepts viability requires a combination of foresight methods. A mechanism that allows for the comparison and quantification of the possibility of being a proven technology in the future, β for the existing fast reactor designs and concepts is proposed as one of the quantitative foresight method. The methodology starts with the identification at the national or regional level, of the factors that would affect β. The factors are then categorized into several groups; economic, social and technology elements. Each of the elements is proposed to be mathematically modelled before all ofmore » the elemental models can be combined. Once the overall β model is obtained, the β{sub min} is determined to benchmark the acceptance as a candidate design or concept. The β values for all the available designs and concepts are then determined and compared with the β{sub min}, resulting in a list of candidate designs that possess the β value that is larger than the β{sub min}. The proposed methodology can also be applied to purposes other than technological foresight.« less

In Situ TEM Multi-Beam Ion Irradiation as a Technique for Elucidating Synergistic Radiation Effects

PubMed Central

Taylor, Caitlin Anne; Bufford, Daniel Charles; Muntifering, Brittany Rana; Senor, David; Steckbeck, Mackenzie; Davis, Justin; Doyle, Barney; Buller, Daniel

2017-01-01

Materials designed for nuclear reactors undergo microstructural changes resulting from a combination of several environmental factors, including neutron irradiation damage, gas accumulation and elevated temperatures. Typical ion beam irradiation experiments designed for simulating a neutron irradiation environment involve irradiating the sample with a single ion beam and subsequent characterization of the resulting microstructure, often by transmission electron microscopy (TEM). This method does not allow for examination of microstructural effects due to simultaneous gas accumulation and displacement cascade damage, which occurs in a reactor. Sandia’s in situ ion irradiation TEM (I3TEM) offers the unique ability to observe microstructural changes due to irradiation damage caused by concurrent multi-beam ion irradiation in real time. This allows for time-dependent microstructure analysis. A plethora of additional in situ stages can be coupled with these experiments, e.g., for more accurately simulating defect kinetics at elevated reactor temperatures. This work outlines experiments showing synergistic effects in Au using in situ ion irradiation with various combinations of helium, deuterium and Au ions, as well as some initial work on materials utilized in tritium-producing burnable absorber rods (TPBARs): zirconium alloys and LiAlO2. PMID:28961199

Improved gas tagging and cover gas combination for nuclear reactor

DOEpatents

Gross, K.C.; Laug, M.T.

1983-09-26

The invention discloses the use of stable isotopes of neon and argon, sealed as tags in different cladding nuclear fuel elements to be used in a liquid metal fast breeder reactor. Cladding failure allows fission gases and these tag isotopes to escape and to combine with the cover gas. The isotopes are Ne/sup 20/, Ne/sup 21/ and Ne/sup 22/ and Ar/sup 36/, Ar/sup 38/ and Ar/sup 40/, and the cover gas is He. Serially connected cryogenically operated charcoal beds are used to clean the cover gas and to separate out the tags. The first or cover gas cleanup bed is held between 0 and -25/sup 0/C to remove the fission gases from the cover gas and tags, and the second or tag recovery system bed between -170 and -185/sup 0/C to isolate the tags from the cover gas. Spectrometric analysis is used to identify the specific tags that are recovered, and thus the specific leaking fuel element. By cataloging the fuel element tags to the location of the fuel elements in the reactor, the location of the leaking fuel element can then be determined.