Development of a Process for Recovering Phosphorus from Sewage Sludge

Abstract

A novel process for effectively recovering phosphorus from waste has been developed. By this process, magnesium ammonium phosphate (hereinafter referred to as MAP) is recovered from anaerobic digestive sludge in sewage. The MAP recovery process involves recovering inorganic fine particles, which include the MAP particles, from digestive sludge through a successive line of separating devices such as, a vibrating screen, a hydro-cyclone, and a revolving-cylindrical type thin flow separator or multi-gravity separator. Continuous tests for MAP recovery carried out to study the performance of this process indicate that it was possible to recover about 90% of MAP.