Abstract
For the purification of urban river water polluted with grey water, a new method applying various kinds of contact materials and aquatic plant as nutrient absorber was invented and its purification capabilities were experimentally made clear. Actual purification plant, whose working volume was 26.4m3, was consisted of contact oxidation tanks and aquatic plant cultivation tank. Oxidation tanks were composed of wavy contact material and porous concrete block. Water lettuce (Pistia stratiotes) was cultivated in an aquatic plant cultivation tank. This purification plant was continuously operated under TOC loading rate of 50-170g/m3/d. TOC was removed at the efficiencies of about 40% and SS and anionic surfactants were effectively removed. Cultivation of water lettuce was succeeded by using the effluent from contact oxidation tank. 30kg (wet weight) of water lettuce were harvested from aquatic plant cultivation tank whose cultivation area was only 2.16m2. Purification of polluted river water using contact materials and aquatic plant was experimentally proved to have a high application potential.
