污泥深度脱水絮凝剂的筛选以及采用无机微粒作为助凝剂对污泥脱水性能的优化

Screening of Flocculants Used in Sludge Deep Dewatering and Optimization of Sludge Conditioning System Applied with Microparticles as Flocculant Aid

该文以毛细吸水时间(CST)和泥饼干度为指标,比较了单一混凝剂、混凝剂-絮凝剂复合(两元系统)对污泥脱水性能的影响,探讨了四种无机微粒作为助凝剂组成三元药剂系统对污泥脱水的影响。结果表明:污泥CST随ePAM投加量的变化有不同的变化模式。支链型ePAM的最佳投加量范围较窄,投加量不足或过量时,CST急速上升。而污泥系统对过量投加的支链化的ePAM容忍度更高。膨润土、胶体硅和水滑石焙烧产物,这三种无机微粒与FeCl3和ePAM复合调理污泥时经优化可以使CST更低。优化后的两元和三元药剂系统均能使泥饼干度达到40%,达到了深度脱水的目的,符合国家相关标准。此外,胶体硅对污泥脱水性能的改善作用较为显著,投加量低,且调理后污泥絮体的抗剪切能力增强,压滤后形成的泥饼干度更高。

Capillary suction time （CST） value from CST testing and cake dryness from pressing testing were used to evaluate the dewatering performance of sludge after conditioning in the paper. Comparison was conducted among coagulant, two components （coagulant-flocculant） system and three components （coagulant-flocculant with the aid of inorganic microparticles）. Results show that the optimal dosage range for linear ePAM is narrow. CST increases sharply if the linear ePAM is underdosing or overdosing. However, it is more tolerant to the overdosing of branched ePAM. Lower CST values of the sludge can be achieved with the aid of bentonite, silica or calcined hydrotalcite （CHT）. Moisture content can reach 60% with the sludge conditioned with optimized FeCl3 ＋ ePAM conditioning system and FeCl3 ＋ microparticle ＋ ePAM system. Silica, out of all the tested micropartieles, is the most significant in enhancing the sludge dewatering performance. The sludge flocs with the aid of silica are more resistant to shear forces and the cake dryness achieved is higher.