Impact of acclimation methods on microbial communities and performance of anaerobic fluidized bed membrane bioreactors (original) (raw)
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Integrated anaerobic fluidized-bed membrane bioreactor for domestic wastewater treatment
Chemical Engineering Journal, 2014
An integrated anaerobic fluidized-bed membrane bioreactor was developed. Methane productivity decreased while more VFAs accumulated with a shorter HRT. The membrane fouling was more serious at a shorter HRT than longer HRT. GAC addition reduced protein content in cake layer and helped membrane filtration. a b s t r a c t An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) system with granular activated carbon (GAC) as carrier was developed to treat domestic wastewater with energy recovery. We investigated a laboratory-scale IAFMBR with chemical oxygen demand (COD) of about 300 mg/L at different hydraulic retention time (HRT). The removal of COD of 75.8%, 73.6% and 54.1% was achieved at respective HRT of 8, 6 and 4 h, resulting in respective methane yield was 140, 180 and 190 L CH 4 (STP)/kgCOD removed and conversion of 45.2%, 53.1% and 43.8% of COD into methane in biogas. The transmembrane pressure of membrane increased more rapidly at a shorter HRT than a longer HRT, suggesting that membrane fouling rate was accelerated at short HRTs. The amount of GAC added into the inner tube of IAFMBR controlled essentially the membrane fouling process. Supplementation of GAC reduced protein content in layer cake and helped membrane filtration.
Journal of Applied Membrane Science & Technology, 2017
Practical use of an anaerobic granular activated carbon (GAC) fluidized bed bioreactor (FBBR) as pretreatment to microfiltration was experimentally verified. A nature starch based cationic flocculants (GF) was employed in this study for testifying its impact on the performance of GAC–FBBR. The GAC–FBBR with and without addition of GF was evaluated in terms of dissolved organic carbon (DOC) removal from biologically treated sewage effluent (BTSE). With only a daily addition of 200 mg GF to GAC– FBBR and a depth of GAC of 500 mm, the biomass of GAC increased from 1.5 g/L to 4.2 g/L within operation period of 30 days while the system resulted in 5% better DOC removal. The results indicate that the GAC–FBBR as pretreatment could effectively remove the dissolved organics and improve the critical flux. Compared with the critical flux of BTSE with submerged microfiltration (SMF) alone (20 L/m2.h), the pretreatment by GAC–FBBR successfully increased the critical flux to 30 L/m2.h. Moreover,...
Separation and Purification Technology, 2010
In this study, laboratory-scale anaerobic fluidized bed bioreactors (AFBBRs) using granular activated carbon as bedding material were employed for treating a primary treated sewage effluent (PTSE) with or without refractory organic pollutants (ROPs). A new starch based flocculant (NSBF) combining a nature starch based cationic flocculants and trace nutrients was prepared and applied in AFBBR. The impact of NSBF on the performance of AFBBR was mainly evaluated in terms of organic and nutrient removal and microbial activity. Membrane fouling based on critical flux was assessed when the bioreactor used as pretreatment for microfiltration. The results 2 indicated that the addition of NSBF in AFBBR (NSBF-AFFBR) not only attained improved organic (9-10%) and nutrient removal (10-20%), higher biomass growth (3.0 g biomass /L GAC) and net bed expansion (18 cm), but also doubled the critical flux (from 15 to 30 L/m 3 .h) in the microfiltration system. In addition, NSBF-AFBBR could retain 10% better DOC removal efficiency at different recirculation rates for treating PTSE with ROPs. When increasing organic loading rate from 21.6 to 43.2 kg COD/m 3 •day, NSBF-AFBBR achieved comparatively constant organic removal of 55% whereas the efficiency in AFBBR alone decreased dramatically from 47 to 34%. Thus, NSBF could act as a performance enhancer for AFBBR.
Bioresource Technology, 2014
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Anaerobic treatment utilizing the function of activated carbon
Water Science and Technology, 1997
Granular activated carbon (GAC) was used as supporting medium for bacteria in anaerobic process. The effectiveness of usina GAC was examined with laboratory•scale experiments. Synthetic wastewater containing phenol was converted to methane more successfully in fluidized bed using GAC. Fluctuation in influent concentration of phenol was intenlionally made to examine the dynamic response of the process. Temporary increase of influent phenol from 400 mg/l to 1000 mg/l. 2000 mg/l. and even to 4000 mg/l for 4 days did not affect the effluent phenol as much as methane production because adso'lltion and desorption capacity by GAC functioned as slllbilizer of the fluctuation. The adsorbed phenol was then gradually degraded into methane. Higher biomass concentration and lower adsorbed phenol were observed in the top part of the fluidized bed than in the bottom part.~1997 IAWQ.
Bioresource Technology, 2012
A specific integrated fluidized bed bioreactor (iFBBR) was optimized in terms of organic loading rate (OLR), hydraulic retention time (HRT) and frequency of new sustainable flocculant (NSBF) addition for primary treated sewage effluent (PTSE) treatment. It was observed that iFBBR achieved the best performance with the operating conditions of 4 times/day NSBF addition, HRT of 90 min and OLR of 8.64 kgCOD/day m 3. The removal efficiencies were found to be more than 93% of dissolved organic carbon (DOC), 61% of total nitrogen (T-N) and 60% of total phosphorus (T-P). iFBBR as pretreatment of submerged microfiltration (SMF) is successful in increasing the critical flux and reducing the membrane fouling. NSBF-iFBBR-SMF hybrid system led to very high organic removal efficiency with an average DOC removal of 97% from synthetic PTSE.
Journal of Environmental Sciences, 2019
The effects of powdered activated carbon (PAC) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor (DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAC-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane (DM) layer. Additionally, PAC addition did not exert very significant influence on the propagation of eukaryotes (protists and metazoans) and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAC improved the bacterial diversity in activated sludge, as PAC addition brought about additional microenvironment in the form of biological PAC (BPAC), which promoted the enrichment of Acinetobacter (13.9%), Comamonas (2.9%), Flavobacterium (0.31%) and Pseudomonas (0.62%), all contributing to sludge flocs formation and several (such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAC addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.