Organic carbon and nitrogen removal from waste water - by biological degradation, nitration and denitrifying in plant contg. immersed percolating filters

摘要

Organic C and N are removed from waste water by biological organic C decomposition and by NH3 oxidn. to gaseous N2, by passing, in radial or axial flow, through a biologically working multi-step waste water clarifier contg. immersed percolating filters. Novelty consists in reducing the growth area of the individual immersed percolating filter rollers exposed, to air-O2/time, from step to step, according to purification progress. This is achieved either by (a) reducing the growth area surfaces projecting out of water or (b) by lowering the speed of rotation of the immersed percolating filter rollers, or by combining (a) and (b) in required proportion. In the claimed waste water clarifier, the immersion depth of the immersed percolating filter rollers increases from step to step. The speed of rotation of the immersed percolating filter rollers falls in proportion to the falling growth area exposed to air-O2. A separate denitrifying step is not needed.