石膏制酸废水零排放处理工程设计实例

A project design example for zero discharge treatment of wastewater from acid production with gypsum

针对某脱硫石膏制酸项目产生的高盐分、高硬度、高碱度废水,为提高全厂废水回用率,拟采用预处理-两级反渗透-NF分盐-高压反渗透-蒸发结晶工艺进行处理,通过反渗透产水回用作循环水补水和浓水蒸发结晶实现零排放。工程运行结果表明:膜系统产水电导率小于800μS/cm,结晶分盐的硫酸钠、氯化钠纯度达到工业盐要求,可作为资源回收利用,工艺运行稳定,有一定的抗冲击负荷能力。

In order to improve the wastewater reuse rate of the whole plant,a combined process of pretreatment-two-stage reverse osmosis-NF salt separation-high pressure reverse osmosis-evaporative crystallization was adopted to treat the high salinity,high hardness and high alkalinity wastewater produced by desulfurization gypsum acidification project.By using reverse osmosis water as the makeup water for recycling and evaporation-crystallization of concentrated water,zero-discharge was realized.The project operation result showed that,the conductivity of the water produced by membrane system was less than 800μS/cm,and the purity of the crystalline sodium sulfate and sodium chloride met the requirement of industrial salt,which could be reclaimed as resource.The system ran stably and also had certain anti-shock loading capability.