Abstract
In Japan, Kasumigaura Lake, Biawako Lake and many other closed water bodies are very serious in water quality. We attribute the water pollution to that the suspended solids flow into closed water body from surrounding environment. Floatation and supply of oxygen by micro-bubble, mild flow up of water by screw pump and biological filtration/oxidation were applied. These technologies were combined in developing a novel system for the purification of lake water. HRT was 10 minute, and 40 ton/d of lake water was treated. Thirsty percent of suspended solids (SS), equivalent to 3.53 mg-SS/L-lake water, was removed. COD decreased from 4.5 mg/L to 2.5 mg/L. The transparency was improved 36%. This system is in self-completion.
