富营养湖泊滇池水华蓝藻的机械清除

MECHANICAL REMOVAL OF HEAVY CYANOBACTERIAL BLOOM IN THE HYPER-EUTROPHIC LAKE DIANCHI

富营养湖泊暴发蓝藻水华时可集聚浓度达n× 10 8— 9cell/L ,利用重力振动、旋振和离心等方法收集富藻水 ,逐次浓缩、脱水后得藻泥 ;根据需要可对藻泥进行干燥 ,得到干藻粉。 2 0 0 1年 4月至 2 0 0 2年 11月在云南滇池以上述方式清除蓝藻水华 35 1d ,共处理富藻水 4 2 6 4 8m3 ,折合清除水华蓝藻干重为 4 6 0 .83t。按所清除的蓝藻干粉的总氮、总磷、总钾、粗有机质及重金属的平均含量计算 ,相当于从试验区水体中去除了氮 (N) 37.33t、磷 (P) 2 .71t、钾 (K)2 .4 9t及粗有机质 2 0 0 .32t;重金属铅 (Pb) 2 .2 89kg、砷 (As) 2 .2 3kg、汞 (Hg) 2 .3kg、镉 (Cd) 0 .5 1kg。表明在富营养湖泊中水华蓝藻大量暴发时 ,采用机械除藻 ,对控制蓝藻水华污染 ,有效降低内源氮。

In eutrophic lakes dense concentration of the outbreak of cyanobacterial bloom could reach up to 10 8-9 cells/l in the water. By using several techniques as gravitational shaking, rotating shaking and centrifuging, the surface water was cleaned out in turn of condensing, dehydrating to harvest the algal mud; and then drying to powder or not according to the further requirement for processing. During April 2001 to November 2002 the technology was applied in lake Dianchi for 351 days. The total amount of treating surface water in lake Dianchi was 42648m 3,amounted to 460.83tons in dry weight of algal powder. In accordance with the composition determination of total nitrogen, total phosphors, total potassium, crude organic matters and heavy metals in algal powder, the removed algal biomass corresponded to taking out of 37.33t(N), 2.71t(P), 2.49t(K), and 200.32t(crude organic matters), as well as the heavy metals of 2.289kg(Pb), 2.23kg(As), 2.3kg(Hg), 0.51kg(Cd) respectively from the lake. The results indicated that the mechanical removing is a feasible and helpful way in the hyper-eutrophic water bodies to control the out-breaking of cyanobacterial bloom and to reduce the inner nutrient load.