Transformation of Phosphorus Forms during Construction of Phosphate Reduction System

Phosphorus forms and phosphorus balance were studied during construction of a phosphate reduction system with high concentration domestic sewage.At loading rate of 1.0 kgCOD/(m3·d),DO of 6 mg/L,temperature of 30 ℃,no sludge discharge and continuous aeration,TP removal was 85%to 93% during operation period of 25 d,and polyphosphate and matrix-bound phosphine in sludge were0.274 mgP/gDS and 3.51×106ngP/kgWS,respectively.44.2 mg per day of external phosphorus was removed in the reactor,totaling 0.77 g of phosphorus,so a phosphate reduction system was successfully constructed.Organic phosphorus(Org-P) and inorganic phosphorus in sludge were 3.0 mgP/gDS and1.43 mgP/gDS,respectively,less than those in seed sludge.H2O-P,NaOH-P,BD-P,NaOH85-P were reduced by 84.1%,13.7%,6.24% and 27.3%,respectively.HCl-P was increased by 68.9%.The transformation of phosphorus forms in sludge was probably Org-P→H2O-P→NaOH-P→BD-P→NaOH85-P→ HCl-P.