High rate thermophilic anaerobic wastewater treatment in compartmentalized upflow reactors

1994 ◽  
Vol 30 (12) ◽  
pp. 251-261 ◽  
Author(s):  
J. B. van Lier ◽  
F. Boersma ◽  
M. M. W. H. Debets ◽  
G. Lettinga
Keyword(s):  
Wastewater Treatment ◽  
Volatile Fatty Acids ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
High Rate ◽  
Organic Loading Rate ◽  
Reactor Performance ◽  
Operation Performance ◽  
Granulation Process ◽  
Typical Sequence

Thermophilic anaerobic treatment of acidified and partially acidified wastewater was studied using Upflow Staged Sludge Bed (USSB) reactors. Reactors were composed of various compartments of which each was equipped with a gas-solid separator. This novel approach for thermophilic wastewater treatment led to a reduction or even elimination of major biological and physical limitations of conventional high rate thermophilic conversion processes. The main achievements of the plugflow reactor were i) very low concentrations of volatile fatty acids (VFA) in the effluent, ii) a high degree of sludge retention, and iii) stable reactor performance. The start-up of the reactors was done with either ‘crushed’ mesophilic granular sludge (MGS) or the digested organic fraction of municipal solid waste (OFMSW) as inoculum. A mixture of VFA and a mixture of sucrose-VFA were used as feed. A good operation performance was achieved within 1 month, and the granulation process of the thermophilic biomass was clearly visible after 1-1.5 months of operation. Within 2-3 months, the organic loading rate could be increased up to 100 kg sucrose-VFA-COD m−3 day−1 with a COD removal efficiency exceeding 90% at a HRT of 2-2.5 h. No significant wash-out of the thermophilic biomass was observed despite the extreme biogas load of 40-50 m3 m−3 reactor day. A certain percentage of sucrose was essential for the thermophilic granulation process; in the reactors treating solely the VFA mixture almost no granules were formed. Nevertheless, also in the latter reactors a satisfactory biomass hold up was observed despite the disperse nature of the sludge. The advantage of using compartmentalized reactors was clearly demonstrated under extreme loading conditions. A typical sequence in the degradation of the partially acidified substrate was found. In the first compartment sucrose was converted, followed by the conversion of butyrate and acetate in the next compartments. Propionate was the most difficult intermediate to degrade, but in the last compartments even this fatty acid was degraded almost completely.

scholarly journals Psychrophilic anaerobic treatment of low strength wastewaters

1999 ◽  
Vol 39 (5) ◽  
pp. 203-210 ◽  
Author(s):  
Salih Rebac ◽  
Jules B. van Lier ◽  
Piet Lens ◽  
Alfons J. M. Stams ◽  
Freddy Dekkers ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Substrate Conversion ◽  
Low Strength

Psychrophilic (2 to 20°C) anaerobic treatment of low strength synthetic and malting wastewater was investigated using a single and two module expanded granular sludge bed (EGSB) reactor system. The chemical oxygen demand (COD) removal efficiencies found in the experiments exceeded 90 % in the single module reactor at an organic loading rate up to 12 g COD dm−3 day−1 and a HRT of 1.6 h at 10-12°C ambient temperature using influent concentrations ranging from 500 to 800 mg COD dm−3. When a two module EGSB system was used at the temperature range 10-15°C, soluble COD removal and volatile fatty acids removal of 67-78% and 90-96% were achieved, respectively, and an OLR between 2.8-12.3 kg COD m−3 day−1 and a HRT of 3.5 h. The second module serves mainly as a scavenger of non-degraded volatile fatty acids (VFA) from the first module. The optimal temperatures for substrate conversion of reactor sludge, after it has been exposed to long term psychrophilic conditions, were similar to those of the original mesophilic inoculum. The specific activities of the sludge in the reactor increased in time by a factor 3, indicating enrichment of methanogens and acetogens even at low temperatures. By adapting the process design to the expected prevailing conditions inside the reactor, the loading potentials and overall stability of the anaerobic high-rate process may be distinctly improved under psychrophilic conditions. The results obtained clearly reveal the big potentials of anaerobic wastewater treatment under low ambient (10-12°C) temperature conditions for low strength wastewaters, very likely including domestic sewage.

Anaerobic baffled reactor treatment of biodiesel-processing wastewater with high strength of methanol and glycerol: reactor performance and biogas production

2011 ◽  
Vol 65 (5) ◽  
Author(s):  
Darin Phukingngam ◽  
Orathai Chavalparit ◽  
Dararat Somchai ◽  
Maneerat Ongwandee
Keyword(s):  
Chemical Oxygen Demand ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Electron Microscopic ◽  
Anaerobic Baffled Reactor

AbstractBiodiesel-processing factories employing the alkali-catalyzed transesterification process generate a large amount of wastewater containing high amount of methanol, glycerol, and oil. As such, wastewater has high potential to produce biogas using anaerobic treatment. The aim of this research was to investigate the performance of an anaerobic baffled reactor for organic removal and biogas production from biodiesel wastewater. The effect of different organic loading rates, varying from 0.5 kg m−3 d−1 to 3.0 kg m−3 d−1 of chemical oxygen demand, was determined using three 22 L reactors, each comprising five separate compartments. Wastewater was pretreated with chemical coagulants to partially remove oil prior to experimentation. Results show that the anaerobic baffled reactor operated at 1.5 kg m−3 d−1 of chemical oxygen demand and ten days of hydraulic retention time provided the best removal efficiencies of 99 % of chemical oxygen demand, 100 % of methanol, and 100 % of glycerol. Increasing the organic loading rate over 1.5 kg m−3 d−1 of chemical oxygen demand led to excessive accumulation of volatile fatty acids thereby making the pH drop to a value unfavorable for methanogenesis. The biogas production rate was 12 L d−1 and the methane composition accounted for 64–74 %. Phase-separated characteristics revealed that the highest chemical oxygen demand removal percentage was achieved in the first compartment and the removal efficiency gradually decreased longitudinally. A scanning electron microscopic study indicated that the most predominant group of microorganisms residing on the external surface of the granular sludge was Methanosarcina.

An Attempt to Develop Aerobic Granular Sludge in Continuous Airlift Reactors

2021 ◽  
Vol 1025 ◽  
pp. 265-272
Author(s):  
Muhammad Syafiq Mohd Shafei ◽  
Zulkifly Jemaat
Keyword(s):  
Wastewater Treatment ◽  
Operation Mode ◽  
Treatment Plant ◽  
Granular Sludge ◽  
Cod Removal ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Aerobic Granules ◽  
Reactor Performance ◽  
Airlift Reactors

Recent advancement on biological wastewater treatment is via granular sludge technology. It is widely known that, aerobic granular sludge has been developed in a batch operation since its discovery. Yet, most of the wastewater treatment plant (WWTP) is operated in continuous mode. Now, the real challenge is how to adopt the granular technology while maintaining present operation mode of WWTP. Thus, this study attempts to evaluate the feasibility of developing aerobic granular sludge in continuous airlift reactors feed with two different substrates, namely glucose and acetate. Two identical airlift reactors (6 L) were employed and operated at room temperature (30°C). Prior to the substrate feeding, both reactors were inoculated with seed sludge obtained from a palm oil mill anaerobic pond. One of the reactors was fed with 2000 mg COD L-1 of glucose (ALR1) and the other reactor with 2000 mg COD L-1 of acetate (ALR2). The hydraulic retention time (HRT) and organic loading rate (OLR) for both reactors were maintained at 4 days and between 0.2 to 0.5 kg m-3day-1 respectively. Dissolved oxygen was maintained between 5.0 and 6.0 mg O2L-1 and supplied by air compressor. The reactor performance was monitored based on COD removal. Aerobic granules developed throughout the study period was evaluated based on granules size and morphology, sludge volumetric index (SVI30) and SVI5/SVI30 ratio analysis. Results showed that ALR1 demonstrated the formation of filamentous-type aerobic granules with most of the SVI30 average at 100 to 190 mL g-1. Ratio SVI5/SVI30 analysis was evaluated at 0.2 and 0.5. The largest granules size obtained during the experiment was about 600 μm on day-136 and average granules size obtained at 200 to 400 μm. ALR1 able to achieve 95% COD removal. For ALR2, round shaped aerobic granules were developed with average SVI30 from 100 to 1000 mLg-1. SVI5/SVI30 analysis indicated an average ratio between 0.7 and 0.9. The average granules size was between 30 to 50 μm and the largest was 78 μm on day-60. 90% of COD removal efficiency was obtained in ALR2. In conclusion, ALR fed with acetate had indicated better aerobic granules characteristics as compared to glucose fed reactor. Furthermore, the study demonstrated that to develop aerobic granules in continuous reactors is feasible.

Ultrafiltration membrane separation for anaerobic wastewater treatment

1994 ◽  
Vol 30 (12) ◽  
pp. 321-327 ◽  
Author(s):  
Ahmadun Fakhru'l-Razi
Keyword(s):  
Wastewater Treatment ◽  
Membrane Separation ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Water And Wastewater Treatment ◽  
Active Biomass ◽  
Biomass Loss ◽  
Scientists And Engineers ◽  
Uf Membranes

Membrane technology has attracted a lot of attention from scientists and engineers in recent years as a new separation process. Various membrane technologies such as reverse osmosis (RO), ultrafiltration (UF) and microfiltration (MF) have been successfully used for a variety of water and wastewater treatment applications. In this study UF membranes of 10 000 nominal molecular weight limit were used in conjunction with an anaerobic reactor to treat wastewater from a brewery. The UF membranes serve to retain active biomass in the reactor, which is essential for a good reactor performance and for the production of a clear final effluent. The reactor was operated over a range of hydraulic retention times and organic loading rates (OLR) in order to evaluate its treatment efficiency. Six steady states were attained over a range of mixed liquor suspended solids (31 000-38 000 mg 1−1). The maximum organic loading rate applied was 19.7 kg COD m−3 d−1 resulting in a methane yield of 0.27 1 CH4 g−1 COD. The percentages of COD removal achieved were above 96%. The results indicated that the UF membranes were capable of efficient biomass-effluent separation thus preventing any biomass loss from the reactor and have potential for treating industrial wastewaters.

scholarly journals Continuous Volatile Fatty Acid Production From Acid Brewery Spent Grain Leachate in Expanded Granular Sludge Bed Reactors

2021 ◽  
Vol 5 ◽  
Author(s):  
Juan Castilla-Archilla ◽  
Jonas Heiberger ◽  
Simon Mills ◽  
Julia Hilbig ◽  
Gavin Collins ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Total Concentration ◽  
Granular Sludge ◽  
Organic Loading Rate ◽  
Hydrogen Yield ◽  
Fatty Acid Production ◽  
Spent Grain ◽  
Total Carbohydrates ◽  
Ph Shock ◽  
Hydrolysis Of

The production of volatile fatty acids (VFAs) in expanded granular sludge bed (EGSB) reactors using leachate from thermal diluted acid hydrolysis of brewery spent grain was evaluated. Partial inhibition of the anaerobic digestion process to induce VFA accumulation was achieved by applying a high organic loading rate [from 15.3 to 46.0 gCOD/(L·day)], and using a feed with an inlet concentration of 15 g/L total carbohydrates. Two EGSB reactors were operated under identical conditions, both inoculated with the same granular sludge. However, granular sludge in one reactor (R1) was subsequently disaggregated to flocculent sludge by a pH shock, whereas granules remained intact in the other reactor (R2). The hydraulic retention time (HRT) of both reactors was decreased from 36 to 24, 18 and 12 h. The main fermented compounds were acetic acid, butyric acid, propionic acid and ethanol. Despite fluctuations between these products, their total concentration was quite stable throughout the trial at about 134.2 (±27.8) and 141.1 (±21.7) mmol/L, respectively, for R1 and R2. Methane was detected at the beginning of the trial, and following some periods of instability in the granular sludge reactor (R2). The hydrogen yield increased as the HRT decreased. The highest VFA production was achieved in the granular sludge reactor at a 24 h HRT, corresponding to 120.4 (±15.0) mmol/L of VFAs. This corresponded to an acidification level of 83.4 (±5.9) g COD of VFA per 100 gram of soluble COD.

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.

scholarly journals Anaerobic treatment of domestic sewage at low temperature

2001 ◽  
Vol 44 (4) ◽  
pp. 33-40 ◽  
Author(s):  
T. Elmitwalli ◽  
Gr. Zeeman ◽  
G. Lettinga
Keyword(s):  
Low Temperature ◽  
Granular Sludge ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
The Novel ◽  
Reactor Performance ◽  
Batch Tests ◽  
Pre Treatment ◽  
Attached Form

The results of research concerning the feasibility of anaerobic treatment of domestic sewage at low temperature are summarized in this article. The batch tests demonstrated a high biodegradability of domestic sewage at 20°C (74%). Both batch and continuous experiments for the treatment of domestic sewage showed that the removal of SS prior to anaerobic treatment of domestic sewage not only provides a stable reactor performance but also improves the removal of both colloidal (CODcol) and dissolved COD (CODdis). The results of the pre-treatment of domestic sewage in an anaerobic filter (AF) and an anaerobic hybrid (AH) reactor showed that the AF reactor is an efficient process for the removal of suspended COD (CODss), viz. 82%, at an HRT of 4 h and 13°C. The novel AF reactor consists of vertical sheets of reticulated polyurethane foam with knobs, where the biomass was only in attached form. For the treatment of pre-settled sewage at 13°C, the AH reactor, with granular sludge, showed a higher total COD (CODt) removal than the UASB reactor as a result of higher CODcol removal. Therefore, the performance of a two-step system, AF+AH (with granular sludge) reactor, was investigated with different HRTs at 13°C. For optimization of CODss and CODdis an HRT of 4+4 h is needed, while for optimization of CODcol removal an HRT of 4+8 h is required. A CODt removal of 71% was achieved with 60% conversion to methane from the removed CODt when the AF+AH system was operated at an HRT of 4+8 h at 13°C.

Influence of Hydraulic Retention Time on Start-Up and Process Stability of Polyurethane Carrier Reactions

1992 ◽  
Vol 25 (1) ◽  
pp. 99-106 ◽  
Author(s):  
M. S. T. Rubindamayugi ◽  
H. J. M. Op Den Camp ◽  
H. J. Lubberding ◽  
H. J. Gijzen ◽  
G. D. Vogels
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Organic Loading Rate ◽  
Process Stability ◽  
Reactor Performance ◽  
Steady State Condition ◽  
Start Up ◽  
Reactor Operating ◽  
Startup Period

Influence of hydraulic retention time (HRT) on start-up of Polyurethane Carrier Reactors treating Volatile Fatty Acids (VFA) based wastewater, at constant organic loading rate (OLR) was investigated. OLR was increased stepwise after start-up to evaluate the influence of HRT on process stability. Four parallel experiements were conducted at HRTs of 48, 24, 18 and 12 hours. Results indicate an influence of HRT on duration of start-up period, and process stability after start-up. The reactor operating at HRT of 24 hours required only a relatively stort start-up period and showed higher process stability under steady-state condition. Analysis of individual VFA degradation indicated that butyrate and propionate consuming acetogenic bacteria increased in sigmoid fashion during start-up. Changes in acetate degradation do not show the true increase of acetoclastic population. Instead they reflect concomitant activity of VFA catabolizing acetogens and aceloclastic methanogens . Immobilized biomass increased exponentially during the first three weeks of start-up. The differences in start-up periods between reactors was probably due to differences in quality and activity of biomass immobilized at different HRTs. The HRT of 24 hours was most optimal to obtain stable reactor performance within a short startup period.

Hybrid reactor performance in pentachlorophenol (pcp) removal by anaerobic granules

2001 ◽  
Vol 44 (4) ◽  
pp. 137-144 ◽  
Author(s):  
M. De Almeida Prado Montenegro ◽  
E. De Mattos Moraes ◽  
H. Moreira Soares ◽  
R. Filomena Vazoller
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Culture Media ◽  
Biogas Production ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Concentration Addition ◽  
Hybrid Reactor ◽  
Reactor Performance

The present research aimed at evaluating pentachlorophenol (PCP) degradation in a hybrid reactor supplied with a mixture of fatty acids (propionic, butyric, acetic and lactic) and methanol. The performance of the reactor is remarkably stable and efficient during PCP additions at range of 2.0 to 21.0 mg/L. The reduction of chemical oxygen demand (COD) was around 97% and methane was found to be 86% in the biogas production. The efficiency of volatile fatty acids breakdown was 93%, 64% and 74% respectively for butyric, propionic and acetic. PCP total removal of more than 99% was reached by granular sludge activities formed during 21 months of reactor operation. Methanogenic microorganisms predominance was noticed with 105 to 106 cells/mL during enumeration on methanol or lactate added to sulfate culture media. The removal rate was 1.07 mg PCP · g−1 VS · d−1 during the highest PCP concentration addition.

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