Application Study On Sludge Lime Stabilization Technology In Municipal Wastewater Treatment Plant

With the improving of the city wastewater treatment rate in our country, theamount of sludge is increasing. The pollution of sludge has become one of the mostimportant problem of the society and environment. So, it is particularly important tostudy sludge treatment and disposal technology, which is adapt to the conditions ofour country, safe and reliable, economical and effective. As a new advancedtreatment technology, sludge lime stabilization technology is paid more attentionbecause of its easy operation, low operation cost and some effect of amountdecreasing, sterilization, and deodorization.In this paper, based on the Fangzhuang WWTP sludge lime stabilizationdemonstration project, the process is studied and improved by laboratory test andproduction test. The following items have been investigated: the economic andtechnological characteristics, conditions of application. The process improvingstrategy and the solutions of dispose and use are proposed. And a comprehensiveevaluation for sludge lime stabilization technology is made.The results of laboratory test indicated that the optimal control parameters are20%lime added and2minute of the mixing time. In the following pile process, thescattered way is better than the stack way for the moisture removing. The pH of thedrying lime sludge is unacted on the proportion of lime and mixing time.The results of production test indicated that, after lime stabilization treatmentand pile for a certain time, the water content, organic content and TN decrease mostly,coliform bacteria and other hygiene indicators are not detected, heavy metals areactivated. And the treatment costs is113yuan/t. In the improving process, we findthat the best parameters for process control are20%lime added and75%to82%water content of original sludge in. In the ways of subsequent dispose and use, thesludge can produce425#cement instead of limestone, cannot directly be used as aroad sub-base material, but can be used on under secondary road by mixing withother substances, cannot be landfilled after mixed with garbage or used as landfill cover.So the wastewater treatment plant sludge lime stabilization technology, as aneconomic effective sludge treatment technology, can achieve good reduction,stabilization, innocuition effects, and the cost is relatively low. The dried sludge hasgreat potential in use as construction material. However, by the limit of lime resourceand the difficulty of subsequent dispose and use, it only can be used as a transitionalor temporary method of sludge treatment and dispose. In the improving process, thetreatment effect, cost effectiveness and national standards should be comprehensivelyconsidered.