壳聚糖絮凝剂在活性污泥调理中的应用

研究了自制的壳聚糖絮凝剂在活性污泥调理中的应用,通过污泥比阻、上清液剩余浊度、泥饼含水率及沉降性能等的测定,重点分析了活性污泥脱水的pH范围、絮凝剂投量和壳聚糖分子量及其脱乙酰度对调理效果的影响,并与絮凝剂聚丙烯酰胺(PAM)和聚合氯化铝(PAC)作了比较,在此基础上还进行了双絮凝剂两段法处理污泥的初步探索。研究发现,壳聚糖作为活性污泥调理剂,投量(干污泥质量百分比)在0.8％～1.2％,pH值在5～8时即有较好的调理效果,与PAM效果基本相当,接近于8％～16％的PAC;壳聚糖相对分子量在30×10~4左右,脱乙酰度在70％左右时有较好的调理效果;双絮凝剂两段法处理污泥,在同等用量时效果好于单絮凝剂一段法。

Application of Chitosan Flocculants to Conditioning Activated Sludge

The study is focused on conditioning activated sludge by self made chitosan flocculant. Effects of pH, chitosan characteristics such as molecular weight, degree of deacetylation and dosage have been studied. Dewaterability was evaluated by specific resistance to filtration(SRF), residual turbidity of supernatant, moisture content of cake and settling behaviours. Sludge dewatering behaviours conditioned with CTS, PAM and PAC flocculants were compared. Dual flocculants were also used in sludge conditioning of two stages. It was found that the sludge conditioned with CTS has better dewaterability than that with PAC. The similar result was obtained when PAM was employed. The optinum conditions were: polymer dosage 0.8-1.2g per 100g dry cake, pH5 - 8, molecular weight 300,000 and dgree of deacetylation 70%. Dual flocculant was found to be more effective than simgle flocculant in sludge conditioning.