Immobilization of activated sludge by PVA–boric acid method

Abstract

A new method (polyvinyl alcohol–boric acid method) for an inexpensive and effective immobilization of activated sludge was developed. Using activated sludge immobilized by this PVA–boric acid method, synthetic waste-water was treated at a high loading rate of 0.5–2.35 kg TOC/m³ day. Total organic carbon and total nitrogen were removed at efficiencies of 93 and 30–40%, respectively. The kinetic constants Y and b for this immobilized activated-sludge process were determined to be 0.594g mixed liquor suspended solids (MLSS)/g TOC and 0.0219 day⁻¹, respectively. The cost calculation of chemicals required for the immobilization of activated sludge by this PVA–boric acid method was proved to be extremely inexpensive for the immobilization of activated sludge.