The waste water from wet flue gas desulfurization（WFGD） system in coal-fuel power plants is enriched of chloride ion. A charged spray drying method was introduced in front of precipitator to deal with the waste water from WFGD system.The migration law and influence on flue gas contribution were investigated. The main harmful waste in the water was fixed to fly ash and then caught by precipitator. The injection of waste water can also enhance the agglomeration of fine fly ash which can improve the efficiency of traditional precipitator. As the waste water is chloride ion enriched

it can promote the oxidation of elemental mercury which can be easily removed by WFGD system. This research provides a new technology of waste water zero emission and simultaneous pollution removal.