A ceramic micro-filtration cross-flow membrane coupled to an aerobic bioreactor has been successfully operated as alternatively the system aerator or as a filter of treated waste in the biological remediation of a food industry waste-stream. Membranes with nominal pore sizes ranging from 1.2 to 0.2 μm with the same air supply provide 20 to 70% higher aeration rates than a traditional ring-sparger. In addition, by acting as a physical barrier, the membrane allowed an indigenous waste-specific microflora to develop (109 cfu/ml) which under conditions of nitrogen deficiency, provided a high level of remediation coupled to very low sludge production. At 25°C (typical waste-stream temperature), with COD inputs of up to 9600 mg/l and BOD5 up to 5300 mg/l, reductions in excess of 95% in membrane permeate levels were obtained. Suspended solids in the permeate were also kept low at less than 25 mg/l.

This content is only available as a PDF.