Struvite precipitation was applied to the removal of NH4-N in semiconductor wastewater. Batch experiments were conducted to examine the effects of final pH, magnesium and orthophosphate dosages and the initial influent concentrations of NH4-N and F on the removals of NH4-N and PO4-P by forming struvite deposits. pH was an important parameter in the simultaneous removals of ammonium nitrogen and orthophosphate. In struvite precipitation, the amount of orthophosphate in the solution affected NH4-N removal much more than that of magnesium ions in some cases. It was revealed that the low and high initial concentrations of NH4-N and F inhibited NH4-N and PO4-P removal efficiencies in struvite precipitation, respectively. We also evaluated field-scale treatment plant incorporated by struvite precipitation process. On semiconductor wastewater with an NH4-N concentration of 155 mg/L, the results obtained showed that the incorporation of the struvite precipitation process brought about a high NH4-N removal efficiency of over 89% on average. (C) 2007 Elsevier B.V. All rights reserved.