Struvite precipitation for ammonia nitrogen removal in 7- aminocephalosporanic acid wastewater

Abstract

7-Aminocephalosporanic acid wastewater usually contains high concentrations of ammonium (NH 4+-N), which is known to inhibit nitrification during biological treatment processes. Chemical precipitation is a useful technology to remove ammonium from wastewater. In this paper, the removal of ammonium from 7-aminocephalosporanic acid wastewater was studied. The optimum pH, molar ratio, and various chemical compositions of magnesium ammonium phosphate (MAP) precipitation were investigated. The results indicated that ammonium in 7-aminocephalosporanic acid wastewater could be removed at an optimum pH of 9. The Mg 2+:NH 4+-N:PO 43--P molar ratio was readily controlled at a ratio of 1:1:1.1 to both effectively remove ammonium and avoid creating a higher concentration of PO 43--P in the effluent. MgCl 2·6H 2O + 85% H 3PO 4 was the most efficient combination for NH 4+-N removal. Furthermore, the lowest concentration of the residual PO 43--P was obtained with the same combination. Struvite precipitation could be considered an effective technology for the NH 4+-N removal from the 7-aminocephalosporanic acid wastewater.