Study Of Optimized Distribution Of Sludge Curing Agent And Solidification Effect Of Sludge

The intensity of dewatered is low and its moisture content is high, dewateredsludge contains a lot of heavy metals and organic matter. It not only will cause seriousenvironmental and ecological problems, but also the strength of the dewatered sludgecan′t reach the strength standard of the landfill directly(50kPa). Sludge solidificationtechnology is often used as a pretreatment of the sludge landfill. Because after dealingwith the solidified sludge, the unconfined compressive strength of the sludgesolidification body will increase, the moisture content and the leaching liquid of thesludge solidification body will decrease, the handling and transport of the sludgesolidification body is easier than the original sludge.In this paper, we study the dewatering sewage from the sewage treatment plant ofthe Yixing city ofJiangsu province. On the cement base,we choice respectively to add asingle skeleton materials (slag, fly ash, bentonite) and two kinds of skeleton material(slag+fly ash, bentonite+slag, fly ash+bentonite) to solidified sludge. Theinfluencing factors are the additive amount of cement and skeleton material content,andthe curing age. The unconfined compressive strength and the moisture content of thesolidified body as the evaluation index. On the basis of the influencing factors and theevaluation index to select the best formula of each case. Then because of the need toquickly reach the requirement of the compressive strength in the practical engineering,so this article choice to add different inorganic salt to improve the best formula of eachcase.The results show that,with the increasing of curing ages, the unconfinedcompressive strength of sludge is increasing and the moisture content is reducing. Onthe cement base to add a single skeleton material, bentonite for the compressive strengthincreasing is the most pronounced. when adding the cement10g and the bentonite20g,the maximum compressive strength of the solidification body can reach1033.77kPaduring the curing ages is21d, fly ash for the moisture content reducing is the mostpronounced. when adding the cement7g and the fly ash20g, the minimum moisturecontent of the solidification body as low as1.52%during the curing ages is21d. On thecement base to add two kinds of skeleton material, bentonite+slag for the compressivestrength increasing is the most pronounced. when adding the cement7g and the slag15g,the bentonite20g,the maximum compressive strength of the solidification body canreach1650.13kPa during the curing ages is21d, slag+fly ash for the moisture contentreducing is the most pronounced. when adding the cement10g and the slag15g, and thefly ash20g, the minimum moisture content of the solidification body as low as3.26%during the curing ages is21d.The results of adding inorganic salt to modify show that, adding inorganic salt can increase the compressive strength, reduce the moisture content and the leaching rate ofthe heavy metal quickly. On cement base base,when adding slag alone with3g MgSO4is optimal, the compressive strength can increase from0.18kPa to126.74kPa quicklyduring the curing ages is7d, when adding fly ash alone with1g CaCl2is optimal, thecompressive strength can increase from0.17kPa to72.12kPa quickly during the curingages is7d, when adding bentonite alone with1g CaCl2is optimal, the compressivestrength can increase from289.57kPa to311.65kPa during the curing ages is7d, whenadding slag+fly ash with3g MgSO4is optimal, the compressive strength can increasefrom162.96kPa to230.73kPa during the curing ages is7d, when adding bentonite+slag with1g Al2(SO4)3is optimal, the compressive strength can increase from543.03kPa to1164.50kPa quickly during the curing ages is7d, when adding slag+flyash with3g MgSO4is optimal, the compressive strength can increase from162.96kPa to230.73kPa during the curing ages is7d, when adding fly ash+bentonite with1gMgSO4is optimal, the compressive strength can increase from369.59kPa to1591.46kPa quickly during the curing ages is7d.