壳聚糖联合聚合氯化铝强化混凝除藻的参数优化

为增强饮用原水中藻类的混凝去除效果，以铜绿微囊藻和水华鱼腥藻为对象，在单因素实验的基础上，采用响应曲面法考察了壳聚糖（CTS）投加量、聚合氯化铝（PAC）投加量、pH值及CTS和PAC的投加顺序对CTS联合PAC混凝除藻的影响.结果表明，混凝去除铜绿微囊藻（叶绿素a含量为45~55μg/L）的最佳条件为：CTS 0.40mg/L、PAC 1.19mg/L、原水pH值7.5、CTS和PAC混合均匀后投加，该条件下模型预测叶绿素a去除率为96.1%（实测值为95.7%）；混凝去除水华鱼腥藻（叶绿素a含量为80~90μg/L）的最佳条件为：CTS 0.25mg/L、PAC 2.00mg/L、原水pH值7.9、先投加CTS后投加PAC，该条件下模型预测叶绿素a去除率为97.9%（实测值为97.0%）.当原水pH值9.0时（模拟高藻原水的碱性环境），混凝去除铜绿微囊藻和水华鱼腥藻的最佳投药顺序均为CTS和PAC混合均匀后投加，实测叶绿素a去除率分别为94.9%和95.3%；混凝铜绿微囊藻的药剂方案为CTS 0.40mg/L、PAC 2.00mg/L，药剂成本为0.0215元/m³，混凝水华鱼腥藻的药剂方案为CTS 0.24mg/L、PAC 2.00mg/L，药剂成本为0.0149元/m³.

Parametric optimization of cyanobacteria coagulation by combining chitosan and polyaluminum chloride

The enhanced removal rate (RR) of Microcystis aeruginosa and Anabaena flos-aquae as a result of the combination of chitosan (CTS) and polyaluminum chloride (PAC) was observed. In order to reveal the effects of CTS, PAC, initial pH and dosing order on coagulation, single factor experiment and response surface methodology were used. In the condition of CTS 0.40mg/L, PAC 1.19mg/L, raw water pH 7.5and PAC/CTS (PAC and CTS premixed), M. aeruginosa(chlorophyll-a (chl-a) 45~55μg/L) could achieve a chl-a RR of 95.7% (close to the prediction of 96.1%). As for A. flos-aquae (chl-a 80~90μg/L), in the condition of CTS 0.25mg/L, PAC 2.00mg/L, raw water pH 7.9and CTS+PAC (CTS added first), could achieve a chl-a RR of 97.0% (close to the prediction of 97.9%). At pH 9.0(a simulation of alkaline algae-containing water), compared with the other two dosing orders, the type of PAC/CTS was the most effective in removing algae, leading to a chl-a RR of 94.9% for M. aeruginosa and 95.3% for A. flos-aquae. The cost of 0.40mg/L CTS and 2.00mg/L PAC for M. aeruginosa removal would be ¥0.0215/m³ and that of 0.24mg/L CTS and 2.00mg/L PAC for A. flos-aquae would be ¥0.0149/m³.