Struvite crystallization in sludge dewatering supernatant using air stripping: results in the new-full scale plant at Treviso WWTP

摘要

The demonstrative plant for struvite crystallization can treat up to 1,5 m~3/h of supernatant flowrate. The crystallization of phosphorus salt on silica sand allows not only to have phosphorus removal but also the possibility to have P recovery using the products of crystallization as P-fertilizer. During five months of experimentation the plant confirmed the possibility to remove P without external reagent addition and to reach the operative pH with air stripping. Good P removal efficiency was showed (conversion 62%, crystallization 54%) coupled with a silica sand growth up to 122%.