pH值及黏土密度对壳聚糖改性絮凝剂除藻效果的影响

Effect of pH and clay density on the algae-removing efficiency using chitosan-modified flocculant

研究了不同p H值的改性絮凝剂对不同p H值铜绿微囊藻的絮凝除藻效果.结果表明：不论是对于室内培养的铜绿微囊藻DS,还是对于野外发生的铜绿微囊藻水华,藻液絮凝后的终点p H值均为影响絮凝效果的关键因素,伴随藻液p H值的逐步升高,需要同步调低絮凝剂的p H值并使终点p H值为7.0~7.3才最有利于形成絮凝体;对于高浮力的野生蓝藻水华,需要提高絮凝剂中黏土的密度才能使絮凝体有效沉降.上述结果说明,在使用壳聚糖改性絮凝剂控制铜绿微囊藻水华时,应根据水体p H值及藻生物量而调整絮凝剂配方,且应优先选择在水体p H值和藻生物量较低时进行控藻.

The effects of the pH of chitosan-modified flocculant and the pH of Microcystis aeruginosa culture on the algae-removingl efficiency were studied in the present work. The results indicate that： 1）The final pH after flocculation was the key factor affecting the flocculation efficiency for both indoor cultured M. aeruginosa and field M. aeruginosa blooms, the final pH should be adjusted to 7.0-7.3 to obtain the best flocculantion effect; 2） clay density should be increased for the efficient sedimentation of high-buoyancy cyanobacterial blooms. These results suggest that the composition of chitosan-modified flocculant must be changed according to the pH of water-body and the algal biomass to obtain the best algae-removing efficiency, and the flocculation process should be carried out when the pH of water-body is low and the algal biomass is small.