Study On Optimal Preparation Of Municipal Sludge Curing Agent And Engineering Improvement Schemein A Landfill Area In Southwest China

Municipal sludge is a kind of by-product of the municipal sewage treatment,containing a large number of organic matter,inorganic matter,bacteria,nutrients and heavy metals and other substances.Due to the limitation of infrastructure construction in that area,a large number of sewage treatment plants in the town have no capacity of sludge treatment.The municipal sewage sludge that cannot be treated in the sewage plant is concentrated in the landfill for treatment,which causes to the excessive load of the landfill and a series of production safety problems.Therefore,it is urgent and important to develop an efficient municipal sludge curing agent to reduce the curing time of sludge and enhance the mechanical properties of the solidified body,so as to reduce the landfill pressure and increase the safety of landfill.In that paper,the municipal sludge coming from a landfill site in southwest China was studied.Under the environment and climate of that area,cement,quicklime,fly ash and sodium persulfate were used as curing materials to prepare the curing agent.The dehydrated municipal sludge was cured and the curing effect of the curing agent was studied.That article first analysis of the sludge solidification technology at domestic and abroad research situation,for the sewage treatment plant of basic properties and characteristics of municipal sludge dewatering,dispensing curing effect good,can fast curing agent for curing of municipal sludge,and to study the effect of curing agent bedding-in sludge,including sludge solidification body unconfined compressive strength,moisture content and water immersion characteristics.Under laboratory conditions,the single-factor test shows that the gain effect of cement,quicklime and fly ash on the unconfined compressive strength of the solidified body ranges from 0～5.0%,0～5.0% and 0～4.0% respectively,and the curing age ranges from 0～7 days.Based on response surface optimization analysis,the best solution for curing factors was: 4.6% cement,4.6% quicklime,2.1% fly ash,and the curing age was4.73 days.The engineering characteristics of municipal sludge cured by the above curing scheme can meet the requirement of unconfined compressive strength greater than 80 k Pa in the specification;Through engineering application research,engineering improvement optimization scheme of curing agent and curing,adopted in cement :quicklime = 1:1,quality 30% curing agent amount of sludge,spreading out the sludge under the thickness of 18 cm,5 days to make a turn,10 days,natural drying solidification body moisture content to meet the urban sewage treatment plant sludge disposal-mixed with argillaceous of landfill is less than 60% of landfill in the index requirements.And the solidified body can keep good shape after being soaked by rain.Among the four curing agent materials,the cement,as an inorganic cementing agent,can form a hard block substance with water and other substances during the curing process,providing a certain compressive strength for the curing body.The Quicklime can be used as a quick solvent of cement in the curing reaction,and hydration reaction occurs with the sludge to produce cement.During the curing process,it can be used as a desiccant to absorb the water in the sludge and promote the formation.It can also be used as a bactericidal agent to inhibit the life activities of microorganisms in the sludge.As an inorganic additive,the fly ash can reduce the content of curing agent cement and quicklime,so as to reduce the cost of curing disposal,and make the sludge form a stronger skeleton in the curing process,which can effectively improve the solidification strength of sludge.The sodium persulfate can destroy the floc structure of sludge,change the physical and chemical characteristics of sludge,and realize water removal and mud-water separation.Through the research results of this paper,the solidification of municipal dewatered sludge in a landfill site in southwest China produced a good reaction result.The unconfined compressive strength and water content of municipal dehydrated sludge can meet the local landfill requirements,and the physical form of the solidified sludge is stable after soaking in water.