宁夏某煤制甲醇生产废水处理工程实例

Case of a WWTP for Coal-to-Methanol Production in Ningxia

煤制甲醇废水具有氨氮高、总氮高、硬度高、悬浮物高、碳氮比低等特点,对其进行处理并实现中水回用的工程实例尚少。宁夏某煤制甲醇生产废水处理工程采用一级高效软化沉淀池QWSTN强化生物脱氮降碳反应器/二沉池/二级高效软化沉淀池/V型滤池处理工艺,总投资为6500万元。实际运行结果表明,该工艺对煤制甲醇生产废水具有显著的处理效果,系统出水水质可稳定满足设计要求。该系统平均处理水量为418 m^(3)/h,进水COD及氨氮平均值分别为798.03、111.06mg/L时,系统出水COD、氨氮平均值分别为22.52、0.41 mg/L;一级高效软化沉淀池进水总硬度(以CaCO_(3)计)平均值为1842.53 mg/L时,系统出水总硬度平均值为113.37 mg/L。该阶段系统的电费及药剂费折算运行成本为4.09元/m^(3)。

The wastewater from coal-to-methanol production has the characteristics of high ammonia nitrogen,high total nitrogen,high hardness,high suspended matter and low carbon to nitrogen ratio,which has few engineering cases for its treatment and water reuse.A coal-to-methanol production wastewater treatment plant(WWTP) in Ningxia adopts the treatment process of first-stage high-efficiency softening sedimentation tank,QWSTN enhanced biological nitrogen and carbon removal reactor,secondary sedimentation tank,second-stage high-efficiency softening sedimentation tank,and V-type filter tank.The total investment of the project is 65 million yuan.The operation results show that the process has a significant effect on the treatment of wastewater from coal-to-methanol production,and the effluent quality of the system can meet the design requirements stably.When the average treatment water quantity of the system is 418 m^(3)/h and the average influent COD and ammonia nitrogen are 798.03 mg/L and 111.06 mg/L respectively,the average effluent COD and ammonia nitrogen are 22.52 mg/L and 0.41mg/L respectively.When the average influent total hardness(CaCO_3) of the first-stage high-efficiency softening sedimentation tank is 1 842.53 mg/L,the average effluent total hardness of the system is 113.37mg/L.At this stage,the system's electricity and chemical operating cost is 4.09 yuan/m^(3).