Abstract: Sewage sludge modified by desulfurization ash and PAM was dewatered and its mechanism studied.The results show that dewatering performance for sludge can be greatly improved by adding desulfurization ash.When desulfurization ash of 3 g稬^-1 is mixed with sludge, the biggest volume of sludge sedimentation is 519.5 ml and the decrease of specific resistance(SRF)47.56%, indicating that desulfurization ash makes EPS breaking away and releasing bound water.Better dewatering performance can be obtained by treating sewage sludge with both desulfurization ash with polyacrylamide(PAM).By comparing particle size distribution and scanning electron micrographs(SEM)for original and modified sludge, it is found that the particle size of sludge flocs is obviously smaller for modified sludge than for original one, the frame structure of its small pore has been changed and solider and denser flocs with larger aperture do formed, which makes moisture in sludge removing more easily.PAM plays a role in bridging of particles by adsorption bridge effect and bigger flocs are formed rapidly from unstable sludge flocs, which is more easily for solid-liquid separation to improve sludge dewatering performance.

Key words: sludge, desulfurization ash, dewatering performance, EPS, flocculent structure

摘要： 利用脱硫灰调理生活污水剩余污泥并探讨了其作用机理,结果显示,脱硫灰可明显改善污泥脱水性能,单独用脱硫灰调理污泥,投加量为3 g·L^-1时,污泥沉降体积最大为519.5 ml,比阻有效降幅达47.56%;脱硫灰使污泥中胞外聚合物(EPS)脱离并释放出结合水,脱硫灰与聚丙烯酰胺(PAM)联用处理污泥可得到比单独投加PAM更好的脱水效果;通过对比脱硫灰处理前后污泥的粒径分布和扫描电镜照片(SEM)发现,经过脱硫灰处理后,污泥絮体粒径较原泥明显减小,污泥絮体细孔的骨架结构被改变,形成更结实致密而具有较大孔径的絮体,使污泥中的水分更容易脱除,PAM有较好的吸附桥连作用,使已脱稳的污泥絮体迅速形成更大的絮体,更易固液分离,从而提高污泥脱水性能。

关键词: 污泥, 脱硫灰, 脱水性能, 胞外聚合物, 絮体结构