PURIFICATION OF WATER

PURPOSE:To efficiently purify the water of a pond, etc., polluted by living waste water, etc., without impairing scenes by supplying the polluted water added with flocculating agents into the underwater root parts of plants floated on the water and allowing the pollutants flocculated by these flocculating agents to settle below the plants. CONSTITUTION:The proper plants, for example, reeds 3, having a high nutrient absorbing power by gregariousness are floated on the water surface in the central part, etc., of the pond 2 and the water 1 is circulated and supplied by a submersible pump 5 and a water feed pipe 6 from below approximately the central parts of the roots 4 extending into the water of the reeds 3. The submersible pumps 5 are installed in pits 7 disposed at approximately symmetrical both shores and are so installed that the flocculating agents 8, such as Ca salt and Al salt, are added at proper ratios into the water 1 which is flowed from the pond 2 into the pit and is fed toward the roots 4 via the water feed pipes 6. Since the reeds are living gregariously on the water surface, the flocculated pollutants eventually move radially in the roots 4 and are settled by the contact settlement effect with the roots 4. The pollutants accumulate as flocculated and settled sludge 9 below the reeds 3.