BIODEGRADATION OF PHENOLS AND CYANIDES USING MEMBRANES WITH IMMOBILIZED MICROORGANISMS

The immobilization of microorganisms on ultrafiltration membranes made from polyacrylonitrile modified chemically with hydrazine hydrate and glutaraldehyde and their application to the biodegradation of phenol and cyanide contained in industrial wastewaters was examined. Three ty pes of microorganism isolated from a mixed population of activated slu dge adapted to phenol and cyanide decomposition were immobilized. Simu lated phenol and phenol-cyanide wastewaters with a concentration of xe nobiotics equal to their concentration in coke sewage were subject to ultrafiltration. The membranes were operated at a pressure ranging fro m 0.5 x 10(5) to 2.5 x 10(5) Pa, at a constant temperature of 298 K an d a constant stirring rate in the bioreactor of 250 rpm. The results o btained were characteristic of each immobilized strain. The membrane w ith a mixture of microorganisms from the strains Agrobacterium radioba cter, Staphylococcus seiuri and Pseudomonas diminuta immobilized on it s surface appeared to be the most effective. The coefficients of pheno l and cyanide biodegradation were 36 and 20.3%, respectively. (C) 1998 Elsevier Science Ltd.