通过研究厌氧消化污泥(ADS)的絮凝调理过程,分析了阳离子聚丙烯酰胺(CPAM)投药量对ADS的脱水性能与絮体理化特性的影响.结果表明,絮凝调理极大地改善了ADS的脱水性能,毛细吸水时间(CST)从原始污泥的(193.6±0.00)s下降到了最佳投药量下的(5.75±0.21)s,离心上清液粘度从原始污泥的(1.47±0.00)mPa·s下降到最佳投药量下的(1.14±0.00)mPa·s.污泥离心上清液中胶体的Zeta电位与表面电荷密度在最佳投药量下均上升到零值附近.污泥絮体粒径大部分随着投药量的增加呈增大趋势,中位直径和体积平均粒径分别从原始污泥的0.13mm和0.25mm上升到了最佳投药量下的1.17mm和1.99mm,其一维分形维数(D1)与二维分形维数(D2)随着投药量的上升而上下波动,在最佳投药量时均达到最大值(D1=1.19,D2=1.41),表明污泥絮体表面更加粗糙,结构更加密实,相应的污泥絮体呈现出了较好的强度和耐剥离效果.此外,不同投药量下污泥内的束缚水主要在30~150℃范围内吸热汽化.
The effect of different doses of cationic polyacrylamide(CPAM) on anaerobic digested sludge(ADS) conditioning was studied.The results showed that flocculation conditioning could highly improve the dewaterability of the ADS.The capillary suction time(CST) values decreased from(193.6±0.00) s for original ADS to(5.75±0.21) s for conditioned ADS at the optimal dosage,and the corresponding supernatant viscosity after centrifugation also decreased from(1.47±0.00) mPa · s to(1.14±0.00) mPa · s.In addition,both the zeta potential and surface charge density for colloids in the centrifugal supernatant reached about zero value at the optimum polymer dosage.With the increase of polymer dosage,the ADS flocs became larger,and both their median diameter and volume average diameter were 1.17 mm and 1.99 mm at the optimal dosage.The corresponding average sizes for the original ADS biosolids were 0.13 mm and 0.25 mm,respectively.The one-dimensional fractal dimension(D1) and two-dimensional fractal dimension(D2) for ADS biosolids fluctuated as the polymer dose increased,but both of them arrived at maximum values,D1=1.19,D2=1.41,at the optimal polymer dosage which meant that the flocs formed at this dosage had the coarsest surface and most compact structure.In addition,the flocs with high strength and erosion-resistance were also observed in the optimum polymer dose range.And TG-DSC analysis for these biosolids indicated the bound water evaporated in the range of 30~150℃.