Zero Discharge of Desulfurization Wastewater Related information

Coal-fired power generation units produce a large amount of flue gas containing sulfur dioxide, which is typically treated using wet flue gas desulfurization (WFGD) methods. Wet FGD has high efficiency, fast reaction rates, and high utilization rates of desulfurization agents. Limestone is commonly used as a desulfurization agent in engineering applications. However, this method poses significant challenges in wastewater treatment, with complex qualities of the desulfurization wastewater.

The wastewater mainly contains suspended solids, sulfates, supersaturated sulfites, heavy metals, and other impurities, many of which are strictly controlled by national environmental protection regulations. It has become the most difficult wastewater to treat in coal-fired power plants and is key to achieving zero discharge of wastewater in these plants. Facing the continuous treatment of desulfurization wastewater, the costs are high and the difficulty is great.

Traditional desulfurization wastewater treatment technologies have issues such as complex operational processes and low efficiency, making the exploration of an effective and economical zero-discharge process for desulfurization wastewater an urgent need. Currently, there are several desulfurization wastewater zero-discharge projects in China that are either in operation or under implementation. There are many related technologies for zero-discharge of desulfurization wastewater.

These mainly include pretreatment (removal of heavy metals, hardness, etc.), membrane concentration and reduction, evaporative crystallization, flue gas evaporation, low-temperature flash evaporation, and concentration of thickened liquid through perforation. Under normal circumstances, the desulfurization wastewater zero-discharge treatment system is mainly divided into the following three processes: (1) Pretreatment, membrane concentration, and evaporative crystallization process; (2) Pretreatment, membrane concentration, and flue gas evaporation process; (3) Low-temperature flash evaporation and thickened liquid drying process.