采用向污泥中外加酶强化污泥水解的处理方式,考察了单一酶和复合酶的加入对城市污水厂剩余污泥的破解及减量化的影响,并探讨了酶水解过程动力学.结果表明,外加酶可以促进污泥中悬浮固体的溶解和大分子有机物的降解.当酶最佳投加量(以TS中加入酶量计)为60 mg/g时,淀粉酶比蛋白酶的水解效果好,SCOD/TCOD由16.3%上升到22.3%,VSS去除率由39.8%提高到54.24%.同时,复合酶的水解效果较单一酶的效果好,当水解温度为50℃,蛋白酶和淀粉酶的比例为1∶3时,水解效果最佳,VSS去除率达68.43%,还原糖、NH+4-N浓度分别由37.29和47.60 mg/L增加至177.8和143.43 mg/L.酶水解过程的前4 h,蛋白酶和淀粉酶活力均呈上升趋势,符合一级反应动力学,水解4 h左右达最大值,分别为2.57 U/mL和4.64U/mL,之后酶活力逐渐下降.
The effects of external enzymes to enhance excess sludge hydrolysis were investigated.Protease and α-amylase were added singly and in combination,and it was found that external enzymes can enhance sludge hydrolysis.When treated with single enzyme,α-amylase had higher efficiency than protease,SCOD/TCOD rose from 16.3% to 22.3% and VSS reduction improved from 39.8% to 54.24 % at the optimal dosage of 60 mg/g(calculated by addition of enzyme in TS).Furthermore,mixture enzymes showed better hydrolysis efficiency than single enzyme.The highest VSS reduction was observed at an enzyme mixture ratio of 1∶3 with protease and amylase when the hydrolysis temperature was 50℃,and the VSS reduction achieved 68.43%.Correspondingly,the concentration of reducing sugar and NH4^+-N rose from 37.29,47.60 mg/L to 177.8,143.43mg/L,respectively.According to the kinetic and enzymatic analysis of hydrolysis process,sludge hydrolysis within prior 4 h was consistent with first-order reaction dynamic.During the hydrolysis,both protease and amylase activity rose gradually,the highest activity observed were 2.57 U/mL and 4.64 U/mL at 4h after hydrolysis.Thereafter,the enzyme activity decreased.