Low-Temperature Anaerobic Treatment of Low-Strength Pentachlorophenol-Bearing Wastewater

2015 ◽  
pp. 55-78
Keyword(s):  
Low Temperature ◽  
Anaerobic Treatment ◽  
Low Strength

Low-temperature anaerobic treatment of low-strength pentachlorophenol-bearing wastewater

2013 ◽  
Vol 140 ◽  
pp. 349-356 ◽  
Author(s):  
J. Lopez ◽  
V.M. Monsalvo ◽  
D. Puyol ◽  
A.F. Mohedano ◽  
J.J. Rodriguez
Keyword(s):  
Low Temperature ◽  
Anaerobic Treatment ◽  
Low Strength

First Proof of Concept for Full-Scale, Direct, Low-Temperature Anaerobic Treatment of Municipal Wastewater

2021 ◽  
pp. 125786
Author(s):  
Anna Christine Trego ◽  
B. Conall Holohan ◽  
Ciara Keating ◽  
Alison Graham ◽  
Sandra O'Connor ◽  
...  
Keyword(s):  
Low Temperature ◽  
Municipal Wastewater ◽  
Anaerobic Treatment ◽  
Full Scale ◽  
Proof Of Concept

Low strength wastewater treatment using emerging anaerobic treatment processes

2019 ◽  
Author(s):  
◽  
Liyuan Hou
Keyword(s):  
Electron Transfer ◽  
Municipal Wastewater ◽  
Anaerobic Treatment ◽  
Methane Yield ◽  
Extracellular Electron Transfer ◽  
Anaerobic Sludge ◽  
Treatment Processes ◽  
Anodic Chamber ◽  
Specific Affinity ◽  
Low Strength

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Anaerobic treatment is a promising and energy saving process for low-strength wastewater treatment. Roles of half saturation constant (Ks) and maximum specific growth rate (umax) in anaerobic treatment systems, however, are often overlooked. This study proposed to apply specific affinity (defined as umax/ Ks) as the key performance indicator of anaerobic processes treating low-strength wastewater. Furthermore, this study provided a new insight into the relationship between specific affinity and population of methanogens in an anaerobic membrane bioreactor (AnMBR) treating low-strength wastewater. High abundance of Methanosaeta (85.8% of total archaea) was linked to the high specific affinity (1.6 x 10[superscript -3] L/mg COD/d) in acclimated anaerobic sludge, resulting in low effluent chemical oxygen demand (COD) concentrations. Short hydraulic retention times (HRTs) are preferred for AnMBRs to treat low strength wastewater at a high volumetric organic loading rate with lower capital costs. However, short HRTs become a potential bottleneck in anaerobic treatment processes because of possible interspecies mass transfer limitations and membrane fouling in AnMBRs. Till now, little is known about how short HRTs would affect effluent water quality that is linked to the specific affinity of anaerobic sludge and their microbial community structures in AnMBRs. In current study, the overall performance, specific affinity of anaerobic sludge, and dynamics of community structures of an AnMBR treating synthetic municipal wastewater at decreasing HRTs (i.e., 24 h, 12 h, and 6 h) was investigated. A decrease in HRT resulted in sludge with high specific affinity. Correspondingly, Methanosaeta became the dominant methanogens in the AnMBR. Both the effluent water quality and methane yield were enhanced. Municipal wastewater contains complex organic constituents while multi-step biochemical processes are involved in anaerobic treatment processes. Two identical AnMBR were operated under decreasing HRTs (24 h, 12 h, and 6 h, respectively) treating low strength wastewater containing different substrate (acetate or glucose, respectively). As a result, microbial communities in the two AnMBRs diverged. The effluent quality and methane yield were enhanced in the acetate fed AnMBR while methane yield decreased in the glucose fed AnMBR as HRT decreased. Correspondingly, the abundance of Methanosaetaceae in the acetate fed AnMBR increased, but it decreased in the AnMBR fed with glucose. Interestingly, hydrogenotrophic methanogens have a higher proportion in the glucose fed AnMBR than in the acetate fed AnMBR. Overall, a minimum HRT higher than 6 h may be required to treat wastewater containing complex organic matter to ensure a successful operation. To treat the sulfate-containing low-strength wastewater, we proposed a newly designed anaerobic microbial fuel cell (MFC) system that could be used to produce electricity and remove sulfate simultaneously. A maximum voltage output of 129 mV was observed under the following feed conditions: that the ratio of lactate: sulfate was 60:20 and 0:10 in the anodic chamber and cathodic chamber, respectively. The decrease in the organic substrate/sulfate ratio in anodic chamber had a great effect on the electricity production, which could be resulted from an increasing DvH attaching on the electrode at a higher sulfate concertation contributes more electrons transfer. However, there was no significant electricity production at the ratio of two presumably because sulfate in the anodic chamber obtained all electrons produced by lactate without transferring to cathodic chamber since the stoichiometric ratio of lactate and sulfate is two. To our knowledge, this was the first time to show the electricity generation by using Desulfovibrio vulgaris Hildenborough (DvH) in such a MFC configuration. Electron microscopic analysis indicated that nanoscale filaments could enhance the extracellular electron transfer of DvH. DvH biofilm, which is necessary for extracellular electron transfer, suggesting that DvH has multiple direct electron transfer mechanisms. This could further benefit the application of DvH to enhance the power output and treat the real sulfate-containing low-strength wastewater.

The Characteristic of the Soluble Microbial Products from an Anaerobic Reactor at Low Temperature

2012 ◽  
Vol 518-523 ◽  
pp. 1808-1812
Author(s):  
Lei Zhang ◽  
Wei Guang Li ◽  
Duo Ying Zhang ◽  
Ke Wang ◽  
Guang Zhi Wang
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Membrane Separation ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Soluble Microbial Products ◽  
Anaerobic Reactors ◽  
Anaerobic Biodegradability ◽  
Microbial Products ◽  
Aerobic Biodegradability

A large amount of soluble chemical oxygen demand (COD) exists in the effluent from anaerobic treatment of wastewater at methophilic temperature, which consists of considerable portion of soluble microbial products (SMP). As the anaerobic treatment of wastewater was significantly influenced by temperature, it is great of importance to investigate the SMP from anaerobic reactors operated at low temperature in order to improve the performance. In this study, two lab-scale UASB reactors were performed to treat synthetic glucose and acetate wastewater respectively at an initial concentration of 1000 mg-COD/L at 15 °C. The SMP was found in the effluent from the glucose-fed UASB, and it was 6% of the influent COD concentration. The SMP did not accumulate in the acetate-fed UASB. The average aerobic biodegradability of the SMP was 90% and it was further enhanced by membrane separation of X100 (membrane with 100 k da molecular weight cut-offs). The anaerobic biodegradability of the SMP was 60%, and it was 100% for the fraction in which the molecular weight (MW) was lower than 10 k da. The fraction of low MW (lower than 10 k da) mainly consisted of 31.7% long chain alkanes and 13.6% esters. The aerobic polishing step is an available polishing step for the anaerobic treatment of wastewater at low temperature.

Enhancement by Low Temperatures of the Anaerobic Induction of Cocklebur Seed Germination

1977 ◽  
Vol 4 (6) ◽  
pp. 849 ◽  
Author(s):  
Y Esashi ◽  
Y Ohhara
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Gibberellic Acid ◽  
Low Temperatures ◽  
Anaerobic Treatment ◽  
Maximal Response ◽  
Benzyl Adenine ◽  
Anaerobic Induction ◽  
Time Period ◽  
Proportional Increase

Non-dormant, upper cocklebur (Xanthium pensylvanicum Wallr.) seeds, incapable of germinating under ordinary conditions, can germinate when previously subjected to anaerobiosis; this has been termed the anaerobic induction of seed germination. Aerobic presoaking of the seeds was also required for successful anaerobic induction, and exerted two counter-acting effects on seed germination. When the time period of aerobic presoaking was sufficiently prolonged, the increasing duration of an anaerobic treatment resulted in proportional increase of germination potential but, when it was short, the effect of the anaerobiosis was saturated in a few days. Prolonging the aerobic presoaking period caused less response of the seed to the anaerobic induction, suggesting the development of some germination-inhibiting system during the aerobic presoaking period. This system could not develop in the absence of O2 or at low temperature. Thus, low temperature during prolonged presoaking produced a maximal response to anaerobic induction. Various germination stimulants, CO2, ethylene, gibberellic acid and benzyl adenine, did not significantly alter the effects of the presoaking.

Anaerobic treatment of landfill leachate by sulfate reduction

2000 ◽  
Vol 41 (3) ◽  
pp. 239-246 ◽  
Author(s):  
J.G. Henry ◽  
D. Prasad
Keyword(s):  
Landfill Leachate ◽  
High Surface ◽  
High Strength ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Sulphate Reduction ◽  
High Rate ◽  
Organic Loading Rate ◽  
Filter Performance ◽  
Low Strength

The present study was conducted to investigate the effectiveness of the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The effects of several COD/SO4 ratios (keeping COD constant) and loadings on anaerobic filter performance were studied and compared with the results from anaerobic filters which followed the methanogenic pathway. Results indicated that the treatability of leachate by sulphate reducing bacteria (SRB) was dependent upon the leachate strength. With high strength leachate (COD=15000 mg/L) from the Keele Valley Landfill, it was found that at lower COD/SO4 ratios (≤1.6) toxic conditions developed in the system that were more inhibitory to the SRB than to the methane producing bacteria (MPB). As the COD/SO4 ratio increased, methanogenesis predominated. No predominance of SRB occurred at any COD/SO4 ratio with high strength leachate. The highest COD removal achieved was about 70% of which 20% was accomplished by the SRB at a COD/SO4 ratio of 1.6 and an organic loading rate (OLR) of 4 kg COD/m3.d. With low strength leachate (COD=1500-3300 mg/L) from the Brock West Landfill, and a COD/SO4 ratio <1, SRB became predominant. In these anaerobic filters in which SRB were predominant, the SRB reduced the COD as well as the MPB could. Sulphide inhibition did not take place at any loading in units treating low strength leachate. Consequently, both SRB and MPB should function at COD/SO4 ratios between 1 and 3. About 60% COD removal was achieved at a loading of 2.8 kg COD/m3.d and a COD/SO4 ratio of 1.0. However at a loading of 6 kg COD/m3.d only 27% COD removal was achieved, all of it through the sulphate-reduction pathway. These OLR values are comparable to those applied in systems where methanogenesis was dominant. It was also observed that once the methanogens were established in the units, it was not possible to displace them completely. However, where methanogenesis had not been previously established, it was found that sulphate-reduction could be the sole pathway for COD removal. From this study, it can be concluded that there is no advantage to the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The other options for increasing the loadings, i.e. the use of high surface/volume filter media (to achieve higher biomass concentrations) or high rate systems are likely to be more successful.

Anaerobic treatment of low-strength synthetic TCF effluents and biomass adhesion in fixed-bed systems

2008 ◽  
Vol 31 (6) ◽  
pp. 535-540 ◽  
Author(s):  
Anuska Mosquera-Corral ◽  
Angela Belmar ◽  
Jacqueline Decap ◽  
Katherine Sossa ◽  
Homero Urrutia ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Low Strength
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