壳聚糖改性铝污泥对铜绿微囊藻的絮凝去除

采用给水厂副产物铝污泥代替黏土作为下沉载体，利用壳聚糖改性，将其用于铜绿微囊藻的絮凝去除.结果表明，壳聚糖与铝污泥以1：50的质量比复合改性后除藻效果明显提高：对于藻密度约为4.88×10⁶cells/mL的含藻水，当改性铝污泥最佳投加量为0.25g/L，30min后藻密度和浊度去除率分别达到100%和98.92%，形成的絮体完整紧实，分形维数值为1.719.通过Zeta电位、SEM等表征分析，此过程主要依靠壳聚糖、铝污泥及藻类之间的"电性中和"与"吸附架桥"等的作用，混凝絮凝过程快速高效且投加量小，最佳环境pH值介于7~9.5，外加NaCl、CaCl₂在离子强度较低情况下基本不影响絮凝沉淀过程.加之铝污泥对水体中的磷具有良好的吸附作用，因此壳聚糖改性铝污泥对淡水水体中铜绿微囊藻的去除及生长抑制具有良好的效果，实现了"以废治污".

Chitosan modified alum sludge for alga M. aeruginosa removal by flocculation

An alternative approach was developed in this study for algae (M. aeruginosa) removal by using chitosan-modified alum sludge, which is a by-product of water purification process in waterworks. The results showed that the chitosan and the alum sludge with a mass ratio of 1:50 had a good efficiency for algae flocculation. The optimal dosage of chitosan-modified alum sludge was 0.25g/L, while the resultant algal density (4.88×10⁶ cells/mL) and turbidity removal rates were 100% and 98.92%, respectively, after 30min sedimentation. The resultant flocs were complete and compact with a fractal dimension of 1.719. Through Zeta potential and SEM analysis, the algal removal process relies mainly on the dual-action of "electrical neutralization" and "adsorption bridging" between chitosan and the alum sludge, exhibiting convenient, fast and efficient feature, but requiring strict pH range of 7~9.5. The external NaCl or CaCl₂ did not affect the flocculation and sedimentation process when the ionic strength is low. Moreover, alum sludge exhibited good performance for phosphorus absorption, while the modified alum sludge had high ability for algae removal in freshwater and the potential for growth control. As a result, the developed technique achieved the goal of "waste used for pollution control".