The anaerobic baffled reactor (ABR): Performance and microbial population at various COD loading rates

Abstract

© Int. J. of GEOMATE. Anaerobic Baffled Reactor (ABR) is one type of high-rate anaerobic reactor equipped with a series of baffles. This baffles plays an important role of biomass retaining, consequently, sludge retention time (SRT) could be operated separately from hydraulic retention time (HRT) without needs of filter or media packing. Three 10-liter laboratory scale ABRs with different compartment numbers (3, 6 and 8 compartments) were operated with constant HRT of 24 hrs. Synthetic carbohydrate-protein wastewater was fed to these reactors with COD loading rate of 4 g COD/l-d. The results evidently showed that the compartmentalized structure of ABR helped retard sludge washout rate. The more compartments, the lower of sludge washout rate was. The ratios of SRT/HRT were found as 35, 73 and 134 d/d in the reactors with three, six and eight compartments, respectively. In addition, COD removal efficiencies were observed with percentages of 74, 78 and 83, respectively. Moreover, studying of the microbial populations by FISH technique proved the existence of microbial phase (methanogens and acidogens) separation in ABR system with six and eight compartments, but not clearly distinguishable in three-compartment ABR.