抄録
Lake Izunuma is a famous place for the coming of migrating flying swans. But, the leftovers of foods which were fed to the waterbirds and their droppings are one of the causes of water pollution.
In order to prevent water pollution of Lake Izunuma, a feeding place system was constructed near the lake. It was reported in the previous report that a build-up of pollutants of 12kg T-N, 1.5kg T-P and 120kg COD were found in the feeding pond which is one of the components of the feeding place system. This means that the pollutants going to Lake Izunuma were reduced.
After this, the polluted water in the feeding pond was introduced into a plant field (constructed wetland) and purification by the plant, Zizania latifolia, which is a food for the swans, was attempted.
The purification rates of 2.6 g/m2/day COD, 2.1 mg/m2/day T-N and 0.11 mg/m2/day T-P were obtained.
