WASTE WATER TREATMENT METHOD AND SEWAGE PURIFYING TANK BY BIOLOGICAL FILTERING METHOD

摘要

PURPOSE:To obtain highly treated water low in BOD and SS by the biological filtration of waste water. CONSTITUTION:In a waste water treatment method due to biological filtration wherein water 7 to be treated is passed througth a biological filter bed 2 composed of a granular carrier with specific gravity of about 1 or less to remove org. matter in the water 7 to be treated by aerobic biological decomposition and suspended particles are also removed by physical filtering action, a weighting body 5 is provided above the biological filter bed 2 composed of the granulare carrier and the biological filter bed 2 is pressed in a usual treatment process by the weighting body 5 to perform treatment. The pressing of the biological bed 2 by the weighting body 5 is released in a washing process to perform washing.