Slaughterhouse wastewater treatment: evaluation of a new three-phase separation system in a UASB reactor

The anaerobic treatment of the wastewater from the meat processing industry was studied using a 7.2 1 UASB reactor. The reactor was equipped with an u nconventional configuration of the three-phase separation system. The efflu ent was characterized in terms of pH (6.3-6.6), chemical oxygen demand (COD ) (2000-6000 mg l(-1)), biochemical oxygen demand BOD5 (1300-2300 mg l(-1)) , fats (40-600 mg l(-1)) and total suspended solids (TSS) (850-6300 mg l(-1 )). The reactor operated continuously throughout 80 days with hydraulic ret ention time of 14, 18 and 22 h. The wastewater from Rezende Industrial was collected after it had gone through pretreatment (screening, flotation and equalization). COD, BOD and TSS reductions and the biogas production rate w ere the parameters considered in analyzing the efficiency of the process. T he average production of biogas was 111 day(-1) (STP) for the three experim ental runs. COD removal varied from 77% to 91% while BOD removal was 95%. T he removal of total suspended solids varied from 81% to 86%. This fact supp orts optimal efficiency of the proposed three-phase separation system as we ll as, the possibility of applying it to the treatment of industrial efflue nts. (C) 2001 Elsevier Science Ltd. All rights reserved.