As a high-quality neutralizing chemical, calcium hydroxide can play a very significant anti-virus filtration function, used in many cities in China, has been widely used in the sludge treatment process, reducing the impact of sludge pollution on the environment. In Hangzhou, the amount of sewage produced every day is 300,000 tons, the sewage in the treatment process, will produce about 200 tons of sludge, at present, the sewage has been properly treated, but the sludge has a high content of organic matter, easy to rot and stink, but also contains parasitic eggs, pathogenic microorganisms and other pathogenic substances, as well as copper, zinc, chromium and other heavy metals, chloride ions and other toxic and harmful substances that are difficult to degrade. If not properly handled, easy to cause secondary pollution. Therefore, calcium hydroxide is an important part of water treatment, and the disposal of sludge has become a subject of wide attention. Calcium hydroxide in order to solve this problem, "simply put, calcium hydroxide use our device, sludge into the carbon out, carbon then into the dry incineration, heat reuse, slag out, at present, calcium hydroxide for sludge treatment invented a lot of methods, but these methods have large investment, slow effect, there are secondary pollution problems in the process," Calcium hydroxide has achieved clean production of sludge treatment and has reached the leading level at home and abroad in similar technical fields. According to reports, at present, the sewage treatment capacity of Hangzhou has reached 280,000 tons per day, the actual amount of sewage generated every day is 160,000 tons, the amount of sludge is 100 tons, with the development of the economy, the amount of sewage is also increasing, and the sludge disposal capacity needs to be further strengthened. At present, the sludge production capacity of Hangzhou is about 107 tons/day, and the first-phase calcium hydroxide project can basically meet the water treatment sludge disposal of urban sewage plants in the district, and the disposal of sludge is no longer landfill treatment. The second phase of the sludge treatment project has been included in the planning, calcium hydroxide is expected to start at the end of this year, the design processing capacity of 130 tons/day, after the completion of the second phase, Hangzhou's sludge disposal capacity will reach 230 tons/day in addition, this technology greatly reduces the treatment cost, at present, the cost of sludge treatment per ton is only about 100 yuan. These costs are closely related to residents' water bills, and the lower the cost of calcium hydroxide treatment, the cheaper the residents' water bills will be after the technology is widely used.