Removing Heavy Metals from Sludge

The heavy metals in sludge. especially flue gas desulphurization wastewater sludge. exceed the standard seriously. which belongs to hazardous solid waste. The annual production of sewage sludge in China has exceeded 50 million tons. It is calculated that only the annual production of flue gas desulphurization wastewater sludge in coal-fired power plants reaches 90 million tons. The heavy metals in sludge. if not disposed of properly. will cause very serious secondary pollution to the ecological environment. This paper introduces the present situation of sludge treatment at home and abroad and the determination and estimation methods of heavy metals in sludge. The advantages and disadvantages of chemical process. electrokinetic treatment. bioleaching process. thermal treatment and stabilization are summarized in detail from the aspects of principle. reaction device. research progress. and hot spot. Furthermore. the authors shed light on the existing problems and development prospects of each method. In the end. the paper puts forward the prospect of economical and efficient implementation device and technical scheme with strong application.