Treatment of clam processing wastewaters by means of upflow anaerobic sludge blanket technology

The ability of upflow anaerobic sludge blanket (UASB) technology to treat wastewaters from a mechanical shucking, clam processing facility was evaluated. Both batch and continuous flow studies were performed at approx. 32°C to evaluate the effects of varying organic loading rate (OLR), hydraulic residence time (HRT), NaCl level, and nutrient additions. Among the parameters measured were biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), various nutrients and gas production. The UASB system proved to be effective, accomplishing soluble BOD5, soluble COD, and TSS removals of 87, 83 and 83%, respectively, under the best conditions considered (average OLR = 13.8 g COD/l/d and average HRT = 3 h). The average conversion of wastewater organics to methane was in the area of 80‰. Sodium levels at and about 5250 mg/l significantly impacted on the performance of the UASB.