硅藻土强化混凝去除铜绿微囊藻的影响因素研究

以原水中常见的铜绿微囊藻为研究对象,研究了联合硅藻土与聚合氯化铝(PAC)强化混凝去除铜绿微囊藻的效果.考察了PAC和硅藻土的投加量、溶液pH值、天然有机物腐植酸(HA)对藻和浊度去除的影响,并用zeta电位分析方法对混凝剂的静电中和能力进行表征.结果表明:硅藻土具有良好的助凝作用,投加其有助于改善絮体的沉降性能,提高铜绿微囊藻的混凝去除效果,PAC为6mg/L,pH值为7~8,硅藻土投加量为30mg/L时,叶绿素a(Chl-a)去除率可达96%,剩余浊度低于0.9NTU. HA存在会明显抑制铜绿微囊藻的混凝去除,当HA浓度大于1.0mg/L时, Chl-a去除率大幅度下降同时剩余浊度明显上升,硅藻土的投加可以在一定程度上缓解负面作用.

Influencing factors of Microcystis Aeruginosa removal by enhanced coagulation with diatomite

Microcystis aeruginosa was selected to explore the removal performance of coagulation by combining PAC with diatomite. The effects of PAC dosage, diatomite dosage, initial solution pH, concentration of humic acid on the removal of algae and turbidity were investigated. The zeta potential of the reaction system in coagulation processes was determined. Results showed that diatomite could effectively improve floc settle ability and algae removal. The Chl-a removal reached 96% and the residual turbidity was less than 0.9 NTU with 6mg/L PAC and 30mg/L diatomite when initial solution pH ranged from 7 ~ 8. The presence of humic acid in water obviously inhibited the coagulation removal of Microcystis aeruginosa. When the concentration of humic acid was higher than 1.0mg/L, the algae removal declined sharply and the residual turbidity increased; the addition of diatomite would mitigate the negative effect to some extent.