Effects of FeCl3 addition on the operation of a staged anaerobic fluidized membrane bioreactor (SAF-MBR)

2016 ◽  
Vol 74 (1) ◽  
pp. 130-137 ◽  
Author(s):  
Eunseok Lee ◽  
Perry L. McCarty ◽  
Jeonghwan Kim ◽  
Jaeho Bae

The effects on sulfur removal and membrane fouling resulting from FeCl3 addition to an anaerobic fluidized membrane bioreactor (AFMBR) in a staged AFMBR (SAF-MBR) was investigated. Total sulfur removal in the SAF-MBR was 42–59% without FeCl3 addition, but increased to 87–95% with FeCl3 addition. Sulfide removal in the AFMBR increased to 90% with addition of FeCl3 at a molar Fe3+/S ratio of 0.54 and to 95% when the ratio was increased to 0.95. Effluent sulfide concentration then decreased to 0.3–0.6 mg/L. Phosphate removals were only 19 and 37% with the above added FeCl3 ratios, indicating that iron removed sulfide more readily than phosphate. Neither chemical oxygen demand nor biochemical oxygen demand removal efficiencies were affected by the addition of FeCl3. When the AFMBR permeate became exposed to air, light brown particles were formed from effluent Fe2+ oxidation to Fe3+. FeCl3 addition, while beneficial for sulfide removal, did increase the membrane fouling rate due to the deposition of inorganic precipitates in the membrane pores.

2021 ◽  
Vol 9 (3) ◽  
pp. 611
Author(s):  
Zhendong Yang ◽  
Zhenghua Liu ◽  
Aleksandra Sklodowska ◽  
Marcin Musialowski ◽  
Tomasz Bajda ◽  
...  

Management of excessive aqueous sulfide is one of the most significant challenges of treating effluent after biological sulfate reduction for metal recovery from hydrometallurgical leachate. The main objective of this study was to characterize and verify the effectiveness of a sulfide-oxidizing bacterial (SOB) consortium isolated from post-mining wastes for sulfide removal from industrial leachate through elemental sulfur production. The isolated SOB has a complete sulfur-oxidizing metabolic system encoded by sox genes and is dominated by the Arcobacter genus. XRD analysis confirmed the presence of elemental sulfur in the collected sediment during cultivation of the SOB in synthetic medium under controlled physicochemical conditions. The growth yield after three days of cultivation reached ~2.34 gprotein/molsulfid, while approximately 84% of sulfide was transformed into elemental sulfur after 5 days of incubation. Verification of isolated SOB on the industrial effluent confirmed that it can be used for effective sulfide concentration reduction (~100% reduced from the initial 75.3 mg/L), but for complete leachate treatment (acceptable for discharged limits), bioaugmentation with other bacteria is required to ensure adequate reduction of chemical oxygen demand (COD).


RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31364-31372
Author(s):  
Mengjing Cao ◽  
Yongxiang Zhang ◽  
Yan Zhang

A novel and amplifying anaerobic electrochemical membrane bioreactor was constructed and operated for a long time (204 days) with synthetic glucose solution having an average chemical oxygen demand (COD) of 315 mg L−1, at different applied voltages and room temperatures.


2020 ◽  
Vol 81 (9) ◽  
pp. 1951-1960 ◽  
Author(s):  
C. S. Cabral ◽  
A. L. Sanson ◽  
R. J. C. F. Afonso ◽  
C. A. L. Chernicharo ◽  
J. C. Araújo

Abstract Two bioreactors were investigated as an alternative for the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, aiming at dissolved sulfide and methane removal. The bioreactors (R-control and R-air) were operated at different hydraulic retention times (HRT; 6 and 3 h) with or without aeration. Large sulfide and methane removal efficiencies were achieved by the microaerated reactor at HRT of 6 h. At this HRT, sulfide removal efficiencies were equal to 61% and 79%, and methane removal efficiencies were 31% and 55% for R-control and R-air, respectively. At an HRT of 3 h, sulfide removal efficiencies were 22% (R-control) and 33% (R-air) and methane removal did not occur. The complete oxidation of sulfide, with sulfate formation, prevailed in both phases and bioreactors. However, elemental sulfur formation was more predominant at an HRT of 6 h than at an HRT of 3 h. Taken together, the results show that post-treatment improved the anaerobic effluent quality in terms of chemical oxygen demand and solids removal. However, ammoniacal nitrogen was not removed due to either the low concentration of air provided or the absence of microorganisms involved in the nitrogen cycle.


2011 ◽  
Vol 64 (1) ◽  
pp. 214-219 ◽  
Author(s):  
Levent Gürel ◽  
Hanife Büyükgüngör

The use of a membrane bioreactor (MBR) for removal of organic substances and nutrients from slaughterhouse plant wastewater was investigated. The chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) concentrations of slaughterhouse wastewater were found to be approximately 571 mg O2/L, 102.5 mg/L, and 16.25 mg PO4-P/L, respectively. A submerged type membrane was used in the bioreactor. The removal efficiencies for COD, total organic carbon (TOC), TP and TN were found to be 97, 96, 65, 44% respectively. The COD value of wastewater was decreased to 16 mg/L (COD discharge standard for slaughterhouse plant wastewaters is 160 mg/L). TOC was decreased to 9 mg/L (TOC discharge standard for slaughterhouse plant wastewaters is 20 mg/L). Ammonium, and nitrate nitrogen concentrations of treated effluent were 0.100 mg NH4-N/L, and 80.521 mg NO3-N/L, respectively. Slaughterhouse wastewater was successfully treated with the MBR process.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
C–Y. Chang ◽  
Roger Ben Aim ◽  
S. Vigneswaran ◽  
J–S. Chang ◽  
S–L. Chen

A laboratory scale membrane bioreactor (MBR) fed on real septic tank effluent was studied at different levels of alkalinity (0, 250 and 500 mg NaHCO3/L addition) and sludge retention time (SRT, complete sludge retention, 10 and 20 days). A long–term operation of 267 days was divided into 5 stages to examine the SRT and alkalinity influences on parameters related to nitrification, chemical oxygen demand (COD) removal, extracellular polymeric substances (EPS) production and membrane cleaning. The results of the study showed that the removals of TCOD, SCOD and NH4+–N varied between 86–94%, 71–86%, and 70–94%, respectively. Appropriate alkalinity supplement and SRT control can enhance the COD removal and nitrification. Irreversible membrane fouling occurred fast and water cleaning for the improvement of filtration capacity was ineffective. The results also revealed that the rejection of EPS played a major role both in the enhancement of removal efficiency as well as the increase of filtration resistance during the operation.


Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yue Li ◽  
Qi Hu ◽  
Da-Wen Gao

An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) was investigated to treat synthetic high-strength benzothiazole wastewater (50 mg/L) at a hydraulic retention time (HRT) of 24, 18, and 12 h. The chemical oxygen demand (COD) removal efficiency (from 93.6% to 90.9%), the methane percentage (from 70.9% to 69.27%), and the methane yield (from 0.309 m3 CH4/kg·CODremoved to 0.316 m3 CH4/kg·CODremoved) were not affected by decreasing HRTs. However, it had an adverse effect on membrane fouling (decreasing service period from 5.3 d to 3.2 d) and benzothiazole removal efficiency (reducing it from 97.5% to 82.3%). Three sludge samples that were collected on day 185, day 240, and day 297 were analyzed using an Illumina® MiSeq platform. It is striking that the dominant genus of archaea was always Methanosaeta despite of HRTs. The proportions of Methanosaeta were 80.6% (HRT 24), 91.9% (HRT 18), and 91.2% (HRT 12). The dominant bacterial genera were Clostridium in proportions of 23.9% (HRT 24), 16.4% (HRT 18), and 15.3% (HRT 12), respectively.


2014 ◽  
Vol 70 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Dao Guan ◽  
W. C. Fung ◽  
Frankie Lau ◽  
Chao Deng ◽  
Anthony Leung ◽  
...  

Conventional membrane bioreactor (MBR) systems have increasingly been studied in recent decades. However, their applications have been limited due to their drawbacks such as low flux, membrane fouling, and high operating cost. In this study, a compact macro-filtration MBR (MfMBR) process was developed by using a large pore size membrane to mitigate the membrane fouling problem. A pilot trial of MfMBR process was set up and operated to treat 10 m3/day of saline wastewater within 4 h. The system was operated under an average permeate flux of 13.1 m3/(m2·day) for 74 days. The average total suspended solids, total chemical oxygen demand, biological oxygen demand, total Kjeldahl nitrogen, and total nitrogen removal efficiencies achieved were 94.3, 83.1, 98.0, 93.1, and 63.3%, respectively, during steady-state operation. The confocal laser scanning microscopy image indicated that the backwash could effectively remove the bio-cake and dead bacteria. Thus, the results showed that the MfMBR process, which is essentially a primary wastewater treatment process, had the potential to yield the same high quality effluent standards as the secondary treatment process; thereby suggesting that it could be used as an option when the economic budget and/or land space is limited.


2016 ◽  
Vol 7 (4) ◽  
pp. 488-501 ◽  
Author(s):  
Wensong Duan ◽  
Qigui Niu ◽  
Xiaoguang Xu ◽  
Wei Li ◽  
Dafang Fu

A submerged dynamic membrane bioreactor (sDMBR) was developed to test the influence of attapulgite (AT) addition on the treatment performances and the microbial community structure and function. The batch experimental results displayed the highest UV254 and dissolved organic carbon (DOC) removal efficiencies with 5% AT/mixed liquid suspended solids addition dosage. The continuous sDMBR results showed that the removal efficiencies of chemical oxygen demand, NH4+-N, total nitrogen and total phosphorus significantly increased in the AT added sDMBR. Excitation emission matrix analysis demonstrated that the protein-like peaks and fulvic acid-like peaks were significantly decreased in both in the mixed liquid and the effluent of the AT added reactor. The obligate anaerobes were observed in the sDMBR with AT addition, such as Bacteroidetes and Gamma proteobacterium in the dynamic membrane, which played an important role in the process of sludge granulation. Bacterial community richness significantly increased after AT addition with predominated phyla of Proteobacteria and Bacteroidetes. Similarly, species abundance significantly increased in the AT added sDMBR. Further investigations with cluster proved that AT was a favorite biological carrier for the microbial ecology, which enriched microbial abundance and community diversity of the sDMBR.


2016 ◽  
Vol 74 (9) ◽  
pp. 2202-2210
Author(s):  
Jia Liu ◽  
Wei Zuo ◽  
Yu Tian ◽  
Jun Zhang ◽  
Hui Li ◽  
...  

A membrane bioreactor (MBR) coupled with a worm reactor (SSBWR) was designed as SSBWR-MBR for sewage treatment and excess sludge reduction. However, total phosphorus (TP) release caused by worm predation in the SSBWR could increase the effluent TP concentration in the SSBWR-MBR. To decrease the amount of TP excreted, chemical treatment reactor was connected after the SSBWR-MBR to remove the excess phosphorus (P). The effects of chemical treatment at different time intervals on the performance of the SSBWR-MBR were assessed. The results showed that a maximum TP removal efficiency of 21.5 ± 1.0% was achieved in the SSBWR-MBR after chemical treatment. More importantly, a higher sulfate concentration induced by chemical treatment could promote TP release in the SSBWR, which provided further TP removal from the SSBWR-MBR. Additionally, chemical oxygen demand (COD) removal efficiency of the SSBWR-MBR was increased by 1.3% after effective chemical treatment. In the SSBWR-MBR, the chemical treatment had little effects on NH3-N removal and sludge production. Eventually, chemical treatment also alleviated the membrane fouling in the SSBWR-MBR. In this work, the improvement on TP, COD removal and membrane fouling alleviation was achieved in the SSBWR-MBR using additional chemical treatment.


2006 ◽  
Vol 53 (6) ◽  
pp. 7-13 ◽  
Author(s):  
H.Y. Ng ◽  
T.W. Tan ◽  
S.L. Ong ◽  
C.A. Toh ◽  
Z.P. Loo

In this study, four similar bench-scale submerged Anoxic/Oxic Membrane Bioreactors (MBR) were used simultaneously to investigate the effects of solids retention time (SRT) on organic and nitrogen removal in MBR for treating domestic wastewater. COD removal efficiencies in all reactors were consistently above 94% under steady state conditions. Complete conversion of NH4+-N to NO3--N was readily achieved over a feed NH4+-N concentration range of 30 to 50 mg/L. It was also observed that SRT did not significantly affect the nitrification in the MBR systems investigated. The average denitrification efficiencies for the 3, 5, 10 and 20 days SRT operations were 43.9, 32.6, 47.5 and 66.5%, respectively. In general, the average effluent nitrogen concentrations, which were mainly nitrate, were about 22.2, 27.6, 21.7 and 13.9 mg/L for the 3, 5, 10 and 20 days SRT systems, respectively. The rate of membrane fouling at 3 days SRT operation was more rapid than that observed at 5 days SRT. No fouling was noted in the 10 days and 20 days SRT systems during the entire period of study.


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