Performance and influencing factors of phosphorus removal in two BAFs with artificial crystal seed media

The phosphorus removal from low concentration phosphorus wastewater in two BAFs with different artificial crystal seed meida and the influence of HRT, Ca/P and pH on the treatment performance were investigated. The results showed that the artificial crystal media BAFs was more efficient than that of the current commercial filter media for phosphorus removal and recovery, and the suitable pH range of wastewater was also enlarged. When the initial phosphorus concentration was 10 mg/L, the optimum operational condition of steel slag base composite meida filter was HRT=30 min, n(Ca)/n(P)=1 and pH=8, as well as the optimum condition of water slag base composite media filter was HRT=60 min, n(Ca)/n(P)=2.5 and pH=8. XRD analysis showed that the reaction products of phosphorus removal by the two artificial crystal seed media filters were all hydroxy calcium phosphate, but its crystallinity was not high, which might due to the production of calcium carbonate in the reaction of phosphorus removal simultaneously.