Demonstration And Assessment Of “Conditioning-high Pressure Squeezing-lowtemperature Thermal Drying” Process In Sludge Treatment And Disposal Of Domestic Sewage In Guangzhou City

With the growth of population and economy,the quantity of sewage and sludge is increasing rapidly.Guangzhou municipal sewage plant excess sludge is much more than the capacity of sludge treatment facilities now.It urgently needs a set of technologies suitable for its own development to solve the sludge problem.This paper introduces the present situation of sludge disposal technology in Guangzhou city sewage treatment plant and analyzes the existing problems.A large sewage treatment plant demonstration project was selected as the research object.The technology of the "conditioning-high pressure squeezing-low temperature thermal drying " is studied,and the technical and economical characteristics of the process are evaluated on the basis of 90 days of operation data.This technology is suitable in Guangzhou.Conditioning process should reduce the adding reagent for the effect of sludge outlet;Squeezing process should select high pressure filter to further reduce the sludge moisture content to 55~65%;Thermal drying should choose low temperature drying process.The demonstration project had adopted “conditioning-high pressure squeezing-low temperature thermal drying "sludge treatment process.The conditioning process using chemical conditioning,accounted for 5.8% of dry sludge dosing.The thermal drying process chose low temperature hot air direct drying,using sealing,insulation design of main body,can effectively control the odor emissions and reduce operating costs.The power consumption of the sludge(with water content 80%)is 68.8 Kw?h /ton,the water consumption is 1.2m3/ton.The moisture content of sludge is 28.4~39.5% after processing,the weight reduced 67% than the original sludge(with water content of 80%),the drying sludge is not dampness and odourless,granular,can be incinerated in cement kiln.The demonstration project(scale of 100000 tons/day sewage plant)uses power as the energy source,the total load is 400 kw,covers an area of 1000 square meters,suitable for only the power supply,and limited land of sewage plant.