ASCENDING FLOW TYPE BIOLOGICAL NITRATING AND DENITRATING METHOD AND APPARATUS

摘要

PURPOSE:To perform nitration and denitration in a single tank and to reduce the washing frequency of a filter bed by a method wherein raw water is guided to a packed bed of a granular solid having a three-dimensional reticulated structure as an ascending stream to guide outflow water to the packed bed of the same type and oxygen-containing gas is supplied to obtain treated water and a part of the treated water is circulated to the packed bed. CONSTITUTION:In an ascending stream biological nitration and denitration method, raw water is guided to the packed bed A packed with a granular solid having a three-dimensional reticulated structure provided in a treatment tank 1 as an ascending stream from a raw water pipe 2 to mainly perform the removal of BOD and SS and biological dentration treatment. Subsequently, outflow water is guided to the packed bed B packed with the granular solid having the three-dimensional reticulated structure separately provided to the upper part of the treatment tank through the porous member C provided in the tank 1 through a porous member C. The removal of residual BOD and SS and biological nitration treatment are performed while oxygen-containing gas is supplied to an air diffusion pipe 8 to obtain treated water and at least a part of the treated water is circulated to the packed bed from the upper part of the tank 1 through a circulating water pump 3.