COUPLING OF WASTE-WATER TREATMENT WITH STORAGE POLYMER PRODUCTION

Storage polymers in bacterial cells can be extracted and used as biode gradable thermoplastics. However, widespread applications have been li mited by high production costs. Ln this study, activated sludge bacter ia in a conventional waste water treatment system were induced, by con trolling the carbon-nitrogen (C:N) ratio in the reactor liquor, to acc umulate storage polymers. Specific polymer yield increased to a maximu m of 0.374 g polymer/g cell when the C:N ratio was increased from from 24 to 144, whereas specific growth yield decreased with increasing C: N ratio. An optimum C:N ratio of 96 provided the highest overall polym er production yield of 0.093 g of polymer/g of carbonaceous substrate consumed, without significantly affecting the organic treatment effici ency in the waste water treatment system.