Fenton氧化联合氧化钙调理对污泥脱水的机理研究

探讨了使用Fenton氧化联合氧化钙全过程(第一阶段:使用硫酸调节污泥p H值;第二阶段:投加Fe2+;第三阶段:投加H2O2;第四阶段:投加氧化钙)对污泥脱水效果及物理化学性质的影响.结果表明,酸化处理可以改变絮体的大小,降低Zeta电位,分散絮体,同时去除部分胞外聚合物(EPS),进而改善了污泥脱水性能.此外,在Fenton氧化的过程中,污泥颗粒、Zeta电位、EPS和比阻(SRF)均呈现逐渐减少的趋势,同时生成氢氧化铁胶体会覆盖在污泥颗粒表面,形成保护性的硬壳,进而使污泥的脱水性能大幅提高.当加入氧化钙时,形成稳定的刚性的结构使污泥颗粒重新聚合,促使生成多孔的脱水通道.中试结果阐明,Fenton氧化过程是实现污泥的深度脱水的关键,并表明各个阶段污泥脱水过程中产生的滤液水质状况.总的来说,本研究提供了在高压下实现污泥深度脱水的新思路,包括:絮体酸溶分散与重聚-保护性氧化-骨架构建.由此看来,Fenton氧化联合氧化钙是一种相对温和且有效的污泥调理方法.

A comprehensive mechanism for deeply dewatering sludge using Fenton's reagent with lime

This study explored the mechanism and processes involved in using Fenton''s reagent with lime, and the influence of using the combination treatment to deeply dewater sludge. The experiment illustrated that the acidification treatment changed flocs size, reduced negative Zeta potential, dispersed flocs, removed partial of extracellular polymeric substances (EPS), and improved sludge dewaterability. Besides, the flocs size, the negative Zeta potential, EPS and the specific resistance to filterability (SRF) gradually decreased across the process of the Fenton oxidation. Meanwhile, the surface of the sludge particles was covered by the ferric hydroxide and formed the protective hard shell. As a result, the sludge dewaterability was further improved. In the process of adding lime, the stable rigid structure was formed to flocculate the sludge particles, resulting in the formation of porous dewatering channels. The pilot-scale experiments indicated that Fenton oxidation processes were the key to accomplishing the deeply dewatering of the sludge. In conclusion, this study provided new insights about how to deeply dewater sludge under high pressure, including:acidification dispersion, protective oxidation, and skeleton construction. It thus appears that the Fenton''s reagent with lime served as a mild oxidation method to dewater sludge.