Anaerobic Baffled Reactor System Research Articles

Formation of anaerobic granular sludge (AnGS) to treat high-strength perchlorate wastewater via anaerobic baffled reactor (ABR) system: Electron transfer characteristic, bacterial community and positive feedback mechanism

Anaerobic granular sludge (AnGS) was cultured to treat high-strength perchlorate (reaching to 4800 mg/L) wastewater by an anaerobic baffled reactor (ABR) system with five equal-volume compartments (C1–C5 compartments). Inoculated sludge completely granulated on day 104 with granule size of 0.50–0.75 mm and perchlorate removal efficiency reaching to 97% (influent perchlorate of 2000–4800 mg/L). The Cyclic voltammetry (CV) capacitance increased from 487.5, 465.8 and 407.8 μF to 576.5, 552.4, 549.6 μF in C1, C3 and C5 compartments of ABR system, respectively, suggesting the electron transfer capacity was enhanced under high-strength perchlorate stress. Meanwhile, adenosine triphosphate (ATP) value and electron transport system activity (ETSA) increased to 25.05, 22.87, 20.43 and 6.22, 4.87, 3.95 of C1, C3 and C5 compartments, respectively. The results suggested that high-strength perchlorate stress improved the microbial metabolic activity, which promoted secretion of extracellular polymeric substances (EPS). The more EPS could facilitate the formation and stability of AnGS under high-strength perchlorate stress. In addition, more reasonable metabolic division of labor in functional bacterial (Thauera and Comamonas) was beneficial to AnGS formation, which achieved high-strength perchlorate efficient removal. Finally, a positive feedback mechanism between AnGS formation and high-strength perchlorate removal was established through EPS, microbial metabolic activity and electron transfer characteristic in ABR system. However, excessive perchlorate (5800 mg/L) would exceed the treatment capacity of AnGS, which resulted in the deterioration of removal performance. This work provided an effective information for AnGS application to treat high-strength perchlorate wastewater.

Evaluation of Regional Domestic Waste Water Treatment Plant Performance in Cimahi City

Domestic wastewater treatment plant performance (WWTP) currently refers to stringent wastewater quality standards (Minister of Environment and Forestry Regulation No. 68 of 2016) considering potential environmental degradation because of pollutants in the wastewater. This study evaluated the performance of the Regional Domestic WWTP in Cimahi City. Cimahi has 10 WWTPs which were operated by an Anaerobic Baffled Reactor system. Periodic monitoring only measured the wastewater characteristics after treatment with parameters: total suspended solids (TSS), ammonia, chemical oxygen demand(COD), biological oxygen demand(BOD), and oil and grease. Therefore, wastewater characteristics were measured before and after treatment at selected WWTP during peak and non-peak hours, with TSS, ammonia, and COD. Important hydraulic factors were also measured: flow velocity at peak and non-peak hours, hydraulic detention time, and sludge height. Effluent from all WWTPs did not meet the standard. However, WWTPs with detention time >2 days produced parameter concentrations closed to the maximum value. The selected WWTP has a 5.7days detention time with removal efficiency for COD 57.52%, and TSS 42.56%, during peak period and COD 60.19% and TSS 34.84% for a non-peak period, but ammonia concentration did not decrease. Overall, WWTP has not been able to meet quality standards and the quality.

The effect of step-feeding distribution ratio on high concentration perchlorate removal performance in ABR system with heterotrophic combined sulfur autotrophic process

In a lab-scale anaerobic baffled reactor (ABR) with eight compartments, the heterotrophic and sulfur autotrophic processes were combined to remove perchlorate. And then, the step-feeding distribution ratio of the heterotrophic perchlorate reduction unit (HPR unit) was optimized to achieve efficient removal of high concentration perchlorate. Under the optimized step-feeding distribution ratio, the perchlorate removal efficiency reached to 99.8% with the influent concentration of 1300 mg/L, indicating that the removal performance of step-feeding was better than that of normal-feeding. A mass balance results showed that the perchlorate removal capacity of the C1-C5 compartments were 11.8 ± 0.6, 13.2 ± 0.2, 11.7 ± 1.0, 8.8 ± 0.2 and 9.8 ± 1.0 g/d during the stage VIII, indicating that the step-feeding can effectively relieve pollutant loading of C1 compartment and improve the perchlorate removal capacity of the C2-C5 compartments. Moreover, the high-throughput sequencing analysis showed that bacterial community was significant difference between the HPR and sulfur autotrophic perchlorate removal (SAPR) units. Principal component analysis (PCA) showed that perchlorate removal was more positive correlation with the forward compartments than the posterior compartments of HPR unit. The study confirms that the optimized step-feeding ratio is beneficial to remove the high concentration perchlorate via combining heterotrophic and sulfur autotrophic processes.

Integrated ABR and UASB system for dairy wastewater treatment: Engineering design and practice

This work designed and assessed the engineering performance of dairy wastewater treatment by an integrated system consisting of an anaerobic baffled reactor (ABR) and an upflow anaerobic sludge blanket (UASB). With fats adsorbed and decomposed, proteins were first denatured coagulated into solids in the ABR treatment process, and this process created suitable conditions for sludge retention in the sludge bed of the UASB. As a result, the combined system achieved a substantial reduction in excess sludge from 3 to 5 t/d to 3 t/m, notable biogas generation, and 98% COD removal, while the other pollutants in the effluent met relevant standards. In addition, the system attained an excellent performance in terms of the energy consumption and water treatment agent amount. Two active plants achieved operation costs lower than 0.5 kW h/t, while stable operations under ambient temperature conditions lasted longer than three years. Engineering practices both technically and economically affirmed the potential of the proposed system for dairy wastewater treatment.

Anaerobic digestion of sludge filtrate using anaerobic baffled reactor assisted by symbionts of short chain fatty acid-oxidation syntrophs and exoelectrogens: Pilot-scale verification

The growing amount of sewage sludge from wastewater treatment plant is an emerging challenge in China. The efficient anaerobic digestion of sludge filtrate generated from hydrothermally pretreated sewage sludge can promote the disposal of sewage sludge. Herein, a pilot-scale anaerobic baffled reactor (ABR) assisted by symbionts of short chain fatty acid-oxidation syntrophs (SFAS) and exoelectrogens was developed to improve its stability and efficiency for filtrate treatment. The results demonstrated that the symbionts of exoelectrogens and SFAS, which were enriched by introduction of electrodes in the ABR system, promoted the degradation of butyric, propionic and acetic acids. Therefore, the COD removal efficiency increased from 74.1% to 86.6% and the methane content increased from 81.5% to 92.2% with methane production rising from 241 to 282 mL/g CODremoved. Furthermore, the economic evaluation indicated that the energy consumption of electrodes was 0.600 kWh/m3 of sludge filtrate, the net energy profited from increased methane was 2.344 kWh/m3 of sludge filtrate. These results confirmed that the ABR system assisted by symbionts of SFAS and exoelectrogens was feasible for treatment of sludge filtrate in terms of both technical and economic level through pilot-scale verification.

Anaerobic digestion of sludge filtrate assisted by symbionts of short chain fatty acid-oxidation syntrophs and exoelectrogens: Process performance, methane yield and microbial community

Sludge filtrate is a kind of special organic wastewater generated from hydrothermally pretreated sewage sludge. The efficient treatment of sludge filtrate can promote the development of sludge recycling technology. Herein, the anaerobic baffled reactor (ABR) assisted by symbionts of short chain fatty acid-oxidation syntrophs (SFAS) and exoelectrogens was applied to treat the sludge filtrate. The influence of fermentation temperature and promotion of methanogenesis via symbionts were focused. The results showed that the COD removal efficiency and methane yield of the ABR system assisted by symbionts at 35 °C (R3) were 11.7% and 11.0% higher than the one at 55 °C (R2), respectively. And the COD removal efficiency and methane yield of the R2 system were 9.1% and 12.9% higher than the traditional ABR system at 55 °C (R1), respectively. Large abundances of exoelectrogens such as Thermincola and Geobacter were found in the R2 and R3 systems, respectively. Moreover, ample Syntrophobacter, Syntrophomonas and Methanobacterium were detected in both R2 and R3 systems. The present research revealed the importance of SFAS, exoelectrogens and hydrogenotrophic methanogens for the improvement of methanogenesis. Besides, the mesophilic condition is conducive to enhancing the methanogenesis rate of sludge filtrate.

Process performance and microbial community functional structure in a thermophilic anaerobic baffled reactor coupled with biocatalysed electrolysis

ABSTRACTIn this study, the performances of a conventional anaerobic baffled reactor (ABR) and an ABR combined with microbial electrolysis cells (MECs) for enhancing degradation of volatile fatty acids (VFAs) were evaluated in 55°C. The ABR-MECs system achieved a total chemical oxygen demand (COD) removal rate of 97.2% and a methane yield of 236 ± 5 mL g−1 CODremoved at organic loading rate (OLR) of 6.9 kg COD m−3 d−1, which were higher than those of the ABR with 77.6% and 207 ± 5 mL g−1 CODremoved, respectively, at OLR of 5.1 kg COD m−3 d−1. The pyrosequencing analysis confirmed that the introduction of MECs into ABR was conducive to establishing stable functional communities of syntrophic fatty acids oxidizing bacteria (SFOB), exoelectrogens and hydrogenotrophic methanogens, such as Syntrophobacter (5.4%), Thermodesulfovibrio (2.0%), Methanobacterium (43.8%), Methanolinea (20.4%). The content of unclassified bacteria increased from 12.4% in the ABR system to 52.3% in the ABR-MECs system. In contrast, the proportion of aceticlastic methanogens decreased from 50.1% in the ABR to 24.5% in the ABR-MECs system. The improved performance of the thermophilic ABR-MECs system resulted from phase separation, wide ecological niche and intensification of methanogenesis process via functional microbes, which significantly enhanced the degradation of propionic acid and acetic acid.

Performance evaluation of anaerobic baffled reactor (ABR) for treating alkali-decrement wastewater of polyester fabrics at incremental organic loading rates.

In this study, an anaerobic baffled reactor (ABR) with four compartments was employed to treat alkali-decrement wastewater of polyester fabrics under different organic loading rates. The stable operation of this reactor was achieved in 70 days at a hydraulic retention time of 36 h and mesophilic temperature of 35 ± 1 °C. It is found that the chemical oxygen demand removal and decolorization of this system can be as high as 79.0% and 87.7%, respectively. The different acidogenesis and methanogenesis in four compartments was acclimated by the variation of pH, oxidation reduction potential values and operational conditions in the spatial distribution of the first to fourth compartments of the ABR system. In addition, the dehydrogenase activity (DHA) and coenzyme F420 concentrations along the four compartments ranged from 67.8 to 185.21 μgTF/(gVSS·h) (TF: triphenyl formazan; VSS: volatile suspended solids) and 0.123 to 0.411 μmol/g, respectively. These results indicated that the ABR could separate acidogenesis and methanogenesis in longitudinal distribution and treat well the alkali-decrement wastewater.

Pengembangan Proses pada Sistem Anaerobic Baffled Reactor untuk Memenuhi Bakumutu Air Limbah Domestik

The wastewater treatment infrastructure had provided by the government mainly through application of communal wastewater treatment plant (WWTP). The treatment process of communal WWTP applied generally anaerobic system, such as Anaerobic Baffled Reactor (ABR) technology, but most of treated water do not meet effluent standard. This paper aims to research the characteristics of the organic removal and treatment upgrading process in the communal ABR system, including process modification or combination with other system. Research carried out in several communal WWTP has applied since the year 2012-2013 in Cimahi City, West Java. Method of evaluation was conducted in the WWTP management through observation of serviced community, operation and maintenance, water quality test both physically and chemicaly. Method of qualitative descriptive for analysis factors affecting the process performance of ABR and potential process upgrading of ABR system according to characteristic of ABR system. The organic removal in ABR system is influenced by the management, existence of pra treatment unit, acclimatization process, water consumption and environment of serviced area. Upgrading process of ABR system can be performed by modification of baffle design, start-up process, maintenance biomass, hybrid system, recirculation systems and application of further treatment. The review these alternative of ABR upgrading process are important in the ABR planning standard to achieve treated water meet effluent standard.

Preliminary Investigation of an Anaerobic Membrane Separation Process for Treatment of Low-Strength Wastewaters

As a result of an evaluation of biomass reduction technologies, anaerobic treatment was found to have potential for the lowest level of biomass production in the treatment of municipal and industrial wastewaters. A limitation of anaerobic wastewater treatment processes for dilute wastewaters and at cold temperatures is the ability to maintain a significant level of methanogenic organisms in the reactor to sustain efficient treatment. A process consisting of an anaerobic baffled reactor followed by membrane separation was proposed for the treatment of low strength wastewaters at colder temperatures. A 4 gpm pilot plant facility was assembled and installed at the West Point wastewater treatment plant in Seattle, to test the feasibility of the anaerobic/membrane separation treatment system. During a 7 month period, 3 different attempts were made for system start up with the result of little methanogenic activity in the anaerobic baffled reactor system. The temperatures during the start up ranged from 10 to 15°C and may have been a significant factor in the inability to generate a significant methanogenic population within the time available. Another aspect of this continuing study to investigate biomass reduction was a cost analysis to evaluate the potential for an anaerobic/membrane process for biomass reduction. The cost analysis showed that the significant capital expenditure for adding a membrane reactor to retrofit an existing secondary treatment system resulted in a greater annual amortization costs than the significant operational cost savings realized by less sludge production, less aeration hp, and excess methane gas production. Because the membrane separation system represented about 90% of the retrofit costs, the cost analysis suggests that a less expensive method be pursued for liquid solids separation after anaerobic treatment of low strength wastewaters. This title belongs to WERF Research Report Series ISBN: 9781843397298 (eBook)

The Performance Characteristics of Anaerobic Baffled Reactor (ABR) Fermentation System

A anaerobic baffled reactor (ABR) with an effective volume of 28.7 L was adopted, and the hydrogen production efficiency was investigated with diluted molasses as the substrate. Using a mixture of aerobic and anaerobic activated sludge, the ABR was start-up with a hydraulic retention time (HRT) of 24 h and 35°C. When the influent chemical oxygen demand (COD) concentration was gradually increased from 500 mg/L to 6000 mg/L after a 63-day operation, the ABR kept a steady state. The increase of influent COD concentration, from 6000 mg/L to 8000 mg/L stage by stage, had the remarkable changes on the fermentative system. The ethanol-type fermentation was formed in the first three compartments, while butyric acid-type fermentation in the 4th compartment. In the steady stage at the influent COD of 8000 mg/L, the biogas (H2) yield was found 61.54 L/d (12.85 L/d) while specific H2 production rate of the activated sludge was 48 L/kgMLVSS∙d. Although the ABR system accumulated hydrogen-producing acetogen, due to the hydrogen-consuming bacteria (methanogen and homoacetogenic bacteria), the hydrogen production efficiency was badly inhibited.

Fermentative Hydrogen Production from Soybean Protein Processing Wastewater in an Anaerobic Baffled Reactor (ABR) Using Anaerobic Mixed Consortia

Fermentative H(2) production from soybean protein processing wastewater (SPPW) was investigated in a four-compartment anaerobic baffled reactor (ABR) using anaerobic mixed cultures under continuous flow condition in the present study. After being inoculated with aerobic activated sludge and operated at the inoculants of 5.98 gVSS L(-1), COD of 5000 mg L(-1), HRT of 16 h and temperature of (35 ± 1) °C for 22 days, the ABR achieved stable ethanol-type fermentation. The specific hydrogen production rate of anaerobic activated sludge was 165 LH(2)kg MLVSS(-1) day(-1), the substrate conversion rate was 600.83 LH(2)kg COD(-1)and the COD removal efficiency was 44.73% at the stable operation status. The ABR system exhibited a better stability and higher hydrogen yields than continuous stirring tank reactor under the same operational condition. The experimental data documented the feasibility of substrate degradation along with molecular H(2) generation utilizing SPPW as primary carbon source in the ABR system.

Hydrogen Production from diluted molasses by anaerobic hydrogen producing bacteria in an anaerobic baffled reactor (ABR)

Abstract Hydrogen production from diluted molasses by anaerobic fermentation bacteria was investigated in a three-compartment anaerobic baffled reactor (ABR) with an effective volume of 27.48 L. After being inoculated with aerobic activated sludge and operated at chemical oxygen demand (COD) of 5000 mg/L and temperature of 35 ∘ C for 26 days, the ABR achieved stable ethanol-type fermentation. The liquid fermentation products, including volatile fatty acids (VFAs) and ethanol, stabilized at 1254, 2053, and 2761 mg/L in the three compartments, respectively. Effluent pH, oxidation–reduction potential (ORP), and alkalinity ranged at 4.3–4.4, - 241 to - 249 mV , and 306 – 334 mg CaCO 3 / L , respectively. The hydrogen yield of the ABR was 32.51 L/d at the stable operation status, specific hydrogen production rate of anaerobic activated sludge was 0.13 L/g MLVSS d, and the substrate conversion rate was 0.13 L/g COD. Hydrogen yields, fermentation types, and acclimatization durations varied in each compartment, with the 1st compartment having lowest hydrogen yield but longest acclimatization duration and the 2nd and 3rd compartments having higher hydrogen yields but shorter acclimatization durations. The study found that the individual compartment configuration in the ABR system provided a favorable environment for different types of anaerobic bacteria. Compared with complete stirring tank reactor (CSTR), the ABR system had a better operation stability and microbial activity, which led to higher substrate conversion rate and hydrogen production ability.

Hydrogen production from diluted molasses by anaerobic hydrogen producing bacteria in an anaerobic baffled reactor (ABR)

Hydrogen production from diluted molasses by anaerobic fermentation bacteria was investigated in a three-compartment anaerobic baffled reactor (ABR) with an effective volume of 27.48 L. After being inoculated with aerobic activated sludge and operated at chemical oxygen demand (COD) of 5000 mg/L and temperature of 35 ∘ C for 26 days, the ABR achieved stable ethanol-type fermentation. The liquid fermentation products, including volatile fatty acids (VFAs) and ethanol, stabilized at 1254, 2053, and 2761 mg/L in the three compartments, respectively. Effluent pH, oxidation–reduction potential (ORP), and alkalinity ranged at 4.3–4.4, - 241 to - 249 mV , and 306 – 334 mg CaCO 3 / L , respectively. The hydrogen yield of the ABR was 32.51 L/d at the stable operation status, specific hydrogen production rate of anaerobic activated sludge was 0.13 L/g MLVSS d, and the substrate conversion rate was 0.13 L/g COD. Hydrogen yields, fermentation types, and acclimatization durations varied in each compartment, with the 1st compartment having lowest hydrogen yield but longest acclimatization duration and the 2nd and 3rd compartments having higher hydrogen yields but shorter acclimatization durations. The study found that the individual compartment configuration in the ABR system provided a favorable environment for different types of anaerobic bacteria. Compared with complete stirring tank reactor (CSTR), the ABR system had a better operation stability and microbial activity, which led to higher substrate conversion rate and hydrogen production ability.

Assessment of desulfurization of natural gas by chemoautotrophic bacteria in an anaerobic baffled reactor (ABR)

The purpose of this study is to evaluate an anaerobic system (ABR) cultured by chemoautotrophic bacteria for biodesulfurization of natural gas. In this study anaerobic baffled reactor with five compartments and active volume of 10 l was used. For increasing solid retention time, reactor was packed by pumice with 0.5–2 cm diameter which active volume decreased to 9 l. Inoculation was performed by activated sludge from municipal sewage treatment, which was kept in anaerobic condition for 1 year. The synthetic wastewater which contains S 2O 3 2− ion was used in start-up and S −2 for running of ABR. Performance of the reactor was evaluated at three equivalent hydraulic retention times (HRT) of 50, 28, and 9 h, with the equivalent loading rate of 0.11, 0.2, and 0.62 mmol S −2 l −1 h −1. Sulfide was converted to elemental sulfur and sulfate, so that more than 61% of the sulfur in the end products was elemental sulfur. Throughout the experiment, biodesulfurization of sulfur waste using ABR system, showed that the process is extremely efficient, and the maximum sulfide removal rate was about 3.03 mmol S −2 l −1 h −1.

An anaerobic baffled reactor for pentachlorophenol degradation

In this paper, the performance of a well designed anaerobic baffled reactor (ABR) under shock load was tested with pentachlorophenolic sodium (PCP‐Na). The reactor tested had a capacity of 16.2 L and consisted of 5 compartments. Normal operation conditions included a COD of 1150 mg/L and a PCP‐Na of 1.5 mg/L. The shock load was generated using a PCP‐Na influent at 17.5 mg/L. The experimental results demonstrated that the ABR system was able to cope with the toxic shock load tested. The determined acetate and methane production indicated that acidogens and methanogens in the first two compartments might be inactivated, but its impacts on the other compartments were relatively light and could quickly recover.