添加不同比例的石灰对污泥稳定化的模糊评价

在污泥处置策略中,污泥碱式干化被认同是一种安全可靠的处置方式。而我国由于大多采用较为原始的推送装置,不仅石灰消耗量大,而且污泥稳定化效果差,难以实现污泥性状的改善。利用自主研发的高效混合器,在脱水污泥中添加质量分数为5%、7%、10%、12%和15%的500目工业石灰后,分别测定添加后污泥的温度、pH、粪大肠菌值以及臭味强度的变化,并采用模糊数学法评价了添加不同比例的石灰对污泥的稳定化效果,结果表明:添加不同比例的工业用生石灰后,污泥的温度从原污泥的30℃分别升高到32.0、36.0、39.2、41.0和43.3℃;污泥中的pH从原污泥的6.5左右均升高到12以上;粪大肠菌值从原污泥的1.08×10-8 g/MPN均降为0.01 g/MPN以下;臭味强度从5级降为2级以下;污泥稳定化程度高,模糊综合评价结果都为一级。因此,添加5%的石灰即可实现污泥的稳定化。

Fuzzy mathematics-based sludge stability evaluation of adding different proportions of lime

Alkaline treatment,although being recognized as a safe and secure method,was restricted in China for lacking of efficient equipment which not only consumed large quantities of lime but also lowed sludge stabilization.After using independently developed efficient mixer,5%,7%,10%,12% and 15% of industrial lime was added into dewatered sludge,changes of temperature,pH,fecal coliform and odor intensity were assayed,sludge stability was evaluated by using fuzzy mathematics.The results show that adding different proportions of industrial lime,sludge temperature increased from the original 30℃ to 32.0,36.0,39.2,41.0 and 43.3℃;pH also increased from the original 6.5 to 12;fecal coliform reduced from the original 1.08 × 10-8 g/MPN to 0.01 g/MPN;odor intensity dropped from five to two;fuzzy comprehensive evaluation achieved a high degree of sludge stability.Therefore,sludge stabilization can be realized by the addition only of 5% of lime.