Optimization Condition of Phosphorus Releasing from Pharmaceutical Waste Sludge

With the short supply of phosphorus (P) resources all over the world, more and more phosphorus –rich excess sludge produced. In this study, a pharmaceutical surplus activated sludge was treated by alkali and ultrasonic to promote the release of phosphorus. The optimization of phosphorus release from pharmaceutical surplus activated sludge by alkali and ultrasonic treatment was investigated. Response surface methodology (RSM) was adopted to optimize the conditions for phosphorus and organic matters’ release. A quadratic model was established to describe phosphorus and organic matter release. The variance was analyzed by Design Expert software and the optimum operation conditions were decided. The results indicated that the quadratic model could well fit the relationship between the release of PO4 3−-P and COD and the influence factors. The order of influence on the release of PO4 3−-P and COD was as follows: pH > TS > ultrasonic power > time. The maximum release of PO4 3−-P was 15.3%.