阳澄湖水源水中藻类的去除研究

藻类是水源水的微污染物,其大量生长将给水厂制水和饮水安全带来诸多影响。试验对比了次氯酸钠氧化除藻,硫酸铝、聚合氯化铝(PAC)混凝沉淀除藻以及氧化和混凝联合除藻的效果,并对次氯酸钠、硫酸铝、聚合氯化铝的投加量以及处理时间进行了优化,确定了经济合理的除藻方案。结果表明,当次氯酸钠投加量为30 mg/L,接触氧化时间为20 min时,除藻率为95.4%;当硫酸铝投加量为140 mg/L时,除藻率为87.3%;当聚合氯化铝投加量为120 mg/L时,除藻率为87.1%;在25mg/L次氯酸钠+ 120mg/L硫酸铝条件下,除藻率为98.3%,沉后水浊度为0.411NTU;在25mg/L次氯酸钠+110mg/L聚合氯化铝条件下,除藻率为98.0%,沉后水浊度为0.379NTU。次氯酸钠的助凝作用大大强化了混凝沉淀效果,从而使沉后水浊度降低,既有效提高了除藻率,又减轻了水厂后续工艺的负荷。

Removal of Algae in Yangcheng Lake Source Water

Algae are micro-contaminants in water bodies, and the growth of algae has adverse impacts on the waterworks production and the drinking water safety. An algal removal study was carried out, by oxidation using sodium hypochlorite, by coagulation and sedimentation using aluminum sulfate and polyaluminium chloride, and by their combination. The dosage and timing of sodium hypochlorite, aluminum sulfate, and polyaluminum chloride were optimized to form an economic and reasonable algae removal plan. The results showed that when 30 mg/L sodium hypochlorite was added and the contact oxidation time was 20 min, the removal rate of algae was 95. 4%. When 140 mg/L aluminum sulfate was added , the algae removal rate was 87. 3%, and when the dosage of polyaluminium chloride was 120 mg/L, the algae removal rate was 87.1 %. When the dosage of sodium hypochlorite was 25 mg/L and the dosage of aluminum sulfate was 120 mg/L, 98. 3% of algae were removed and the sedimentation effluent turbidity was 0. 411 NTU. When the dosage of sodium hypochlorite and polyaluminum chloride were 25 mg/L and 110 mg/L respectively, the removal rate of algae was 98. 0% and the sedimentation effluent turbidity was 0. 379 NTU. The coagulation aid effect of sodium hypochlorite enhanced the effect of coagulation and sedimentation and reduced the turbidity of the sedimentation effluent, which effectively increased the algae removal rate and relieved the load of the subsequent processes in the waterworks.