The Anaerobic Baffled Reactor (Abr): Performance and Microbial Population at Various Cod Loading Rates

Abstract

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.

Operational experience with a full‐scale anaerobic baffled reactor treating municipal wastewater

“…A similar phenomenon like the observed sludge lift due to the degassing of the sludge bed was not found in the reviewed literature. Mixing conditions in anaerobic systems mainly depend on the hydraulic conditions and the biogas generation (Barber & Stuckey, ; Chinwetkitvanich & Ruchiraset, ; Krishna et al., ; Langenhoff et al., ; Lettinga, Rebac, & Zeeman, ). Principally, both factors can influence the sludge transfer between the chambers in ABR.…”

Anaerobic Treatment of Domestic Wastewater

“…An ABR was developed in the 1970s by McCarty and co-workers. It is a compartmentalized reactor composed of a series of UASB reactors in which alternating hanging and standing baffles are placed to direct the liquid flow upward and downward from one section to the next (Chinwetkitvanich & Ruchiraset, 2017). High concentrations of biomass are retained in the upflow region of each compartment resulting in high performances, whereas overall sludge production is characteristically low (Bajpai, 2017;Gömec, 2010).…”

“…The two-phase mode can significantly increase acidogenic and methanogenic performance because the different bacterial groups can operate under optimized operational conditions. This is particularly important for methanogenic bacteria, which are not affected by the possible pH decrease derived from the accumulation of volatile acids produced in the acidogenic phase Chinwetkitvanich & Ruchiraset, 2017;Tomei et al, 1994). Furthermore, at low temperatures, the compartmentalization might improve the hydrolysis of less biodegradable substrates in the first zone of the reactor where the pH is low.…”