China Nonferrous Metallurgy

The impurity content of smelting raw material in a Pb-Zn smelter gradually increased, the former “lime-iron salt” process to treat heavy metal wastewater no longer meets the reuse requirements, especially with the thallium content going far beyond the limit. Therefore, the existing wastewater treatment process was upgraded and reconstructed, the process of heavy metal wastewater biologicals for advanced treatment and coordinated thallium removal were introduced into the plant. When using this process to treat Pb-Zn wastewater,the better process conditions are stabilizer 0.7mL/L and biologicals 0.7mL/L for the primary treatment system, and stabilizer 0.3mL/L and biologicals 0.3mL/L for the secondary treatment system; after treatment under these conditions, the content of heavy metals and thallium in the effluent is all stable and in compliance with the discharge standards. This process has been stably operated for two years, saving wastewater treatment cost by 5.2 million CNY each year, the goal of resource utilization and reduced discharge has been reached; it has also reduced the environmental risks and provided technical support for bio-environmental governance, and has larger application value.