The desulphurization wastewater treated by conventional chemical precipitation method was difficult to meet the requirement of reclaimed water used as process water for the FGD system. Advanced wastewater treatment process was urgently needed for the realization of zero liquid discharge of FGD wastewater. The nanofiltration membrane technology was used as advanced treatment for the FGD wastewater from coal-fired power plants in this paper. The effects of operating pressure

operating temperature

operating time

typical residual pretreatment reagent and concentration factor on the treatment effect were studied

and the crystalline precipitates were analyzed. The experimental results showed that

condition with operating pressure of 2.50 MPa and operating temperature of 25 ℃ was the appropriate operating condition. Under this condition

the residual concentration of TDS

chloride

fluoride

sulfate and calcium in the effluent were 2 720

719.9

1.97

213 and 24.8 mg/L

respectively

and the heavy metals were in trace amounts. The effluent quality met the requirement of reclaimed water used as process water for the FGD system

and it realized the goal of saving water and reducing wastewater emissions. In addition

the permeate flux and the rejection rate of dissolved salts reduced with the existence of residual Al3+ and PAM

and keeping a right concentration factor and removing the precipitated gypsum were the keys of controlling the fouling of membrane and reducing the clean frequency.