ANAEROBIC BAFFLE REACTOR (ABR) PROCESS FOR TREATING A SLAUGHTERHOUSE WASTE-WATER

Experiments on ABR were conducted to investigate its efficiency on organic carbon removal. Laboratory scale ABR units were used to treat the dissolved air flotation pre-treated slaughterhouse wastewater with COD concentration range from 480 to 730 mg L-1. The steady-state performance was evaluated under organic loading rates (OLR) from 0.67 to 4.73 g COD L-1 d-1 and hydraulic retention time (HRT) of 2.5 to 26 hr. The ABR was started up at an OLR of 0.67 g COD L-1 d-1 HRT of 26 hr and at ambient temperature (30 to 35-degrees-C in day time and 25 to 30-degrees-C in night time). A treatment efficiency up to 90% on a total COD basis was achieved within 8 days of operation. Once started, the system could satisfactorily handle OLR up to 4.73 g COD L-1 d-1 at HRT of 2.5 hr. Treatment efficiency up to 75% was reached on a total COD basis and to 84% on a filtered COD basis. A conversion of COD removed into methane of 78% was obtained. Gas production was about 0.10 to 0.22 L g-1 applied COD. Biogas produced contained 20 to 27% nitrogen, 69 to 73% methane and 2 to 4% carbon dioxide. The experimental work has shown that ABR is efficient for the treatment of slaughterhouse wastewater and compares favourably with other novel anaerobic systems.