FRACTION OF PHOSPHORUS COMPOSITION IN SEWAGE SLUDGE AND ITS STATE CHANGE BY ACID TREATMENT

Abstract

 In order to recover the phosphorus from sewage sludge and to prevent from the trouble at incineration plants caused by phosphorus in sludge, fractionation analysis of phosphorus in sewage sludge of eleven municipal sewage treatment plants and acid treatments were performed. The results of fractionation analysis showed that phosphate fractions and particulate phosphate fraction in digested sludge ranged 73 to 89% and 24 to 62%, respectively. The results of acid treatments showed that particulate phosphate fraction could be dissolved to phosphate ion thoroughly at the pH condition of 2 with sulfuric acid, 5 with citric acid, or 4 with acetic acid. Judging from these results, dissolved fraction of phosphorus in digested sludge will be able to increase more than doubled using with acid treatment.