不同氮磷含量对蓝藻水华形成的影响及硅藻土复合PAC混凝除藻效果的研究

The Influence of Cyanobacteria Bloom about Different Content of Nitrogen and Phosphorus and the Research of Diatomite Composite PAC Coagulation Effect to Remove Algae

蓝藻水华现象在城市湖库中普遍存在,给人民群众带来极差的感官体验.实验通过采取沈阳市北陵公园北运河、荷花湖、大湖三个湖的水样作为对比,模拟蓝藻生长条件在实验室人工气候箱内培养蓝藻,主要探讨不同氮磷含量对蓝藻形成速度的影响,以及蓝藻水华爆发后,氮磷、COD、pH和浊度的变化;同时采用硅藻土复合聚合氯化铝进行混凝除藻实验,通过观察及测定上清液叶绿素含量和浊度,探讨不同投加方式(搅拌、加滤纸、加PET无纺布)对蓝藻去除效果的影响.结果表明:氮磷含量相对较高的北运河在15天后最先长出蓝藻,其次为荷花湖20天,大湖26天.蓝藻水华后,氮磷含量下降,COD、pH和浊度升高.当硅藻土投加量为40 mg/L,PAC为15 mg/L时,搅拌方式蓝藻絮凝效果最快,3小时开始絮凝沉降.加滤纸和PET无纺布18小时开始有明显絮凝沉降效果,且蓝藻附着在滤纸和PET无纺布下部.搅拌处理后的水体叶绿素含量和浊度降低程度略优于加滤纸和无纺布的处理方式.

Cyanobacteria bloom phenomenon is widespread in the lake city and bring to the people of poor sensory experience.Experiments by comparing the north river,lotus river and the big river in Beiling park,and simulating algae growing conditions in the laboratory of artificial climate box to cultivate algae to discuss the influence of different nitrogen and phosphorus content of blue-green algae forming speed mainly,and the change of nitrogen and phosphorus,COD,pH and turbidity after the outbreak of algae blooms.At the same time using diatomite composite PAC to remove algae.Discussing the removal effect on algae of different dosing methods(stirring,filter paper and non-woven fabric)through the observation and determination of chlorophyll content and turbidity of the supernatant fluid.The results show that the north river with relatively high nitrogen and phosphorus content firstly form the blue-green algae within 15 days,followed by the lotus river 20 days,the big river 26 days.After the outbreak of algae blooms,the content of nitrogen and phosphorus decrease,and the content of COD,pH and turbidity increase.When the amount of diatomite is 40 mg/L,PAC is 15 mg/L,the mixing way of remove cyanobacteria is the fastest,about 3 hours.And the filter paper and non-woven fabric is 18 hours,and cyanobacteria attach at the bottom of the filter paper and non-woven fabrics.the mixing way to decrease water chlorophyll content and turbidity was slightly better than with filter paper and non-woven fabrics.