| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method which can reduce the amount of a flocculant, extend the lives of a filter layer and an activated carbon layer and clarify untreated water to get BOD of 1 mg/liter for the treated water in a clarification process by treating the untreated water with a biological membrane before the untreated water is intro duced into a water reception tank or a settling pond, in the clarification of the waste water of a river, a lake, or the like. SOLUTION: Adequate pieces of tubular water treatment tanks 1-6, which have many honeycomb-like and tubular structure inside and are respectively provided at their lower parts with air-spraying pores 1a-6a, are each independently arranged in parallel in the horizontal direction and their lower parts are formed to communicate with each other. Untreated water is treated by aeration by repeatedly circulating the untreated water in honeycomb-like wall (h) with air spraying while introducing the untreated water into the first water treatment tank 1 and by the biological membrane formed on and adhered to the honeycomb-like wall (h), and then, the water is sent to the second water treatment tank 2 and treated in the same manner as in the first water treatment tank 1. Such a treatment is successively repeated to the last water treatment tank in accordance with the natural clarification processes such that the river carries out.</p> |
