Effluent water treatment to remove nitrogenous and organic materials - by passing successively through denitrification and nitrification zones

摘要

Removal of organic substances and nitrogen cpds. from effluent waters with the aid of microorganisms is described. The water is passed continuously and successively through a denitrification zone and a hitrification zone and part of the liquor emerging from the nitrification zone is returned to the denitrification zone, whilst the remainder is withdrawn. Part of the effluent water to be treated is passed directly to the nitrification zone. The ratio of the feed of effluent water to the denitrification zone to the feed of effluent water to the nitrification zone and the amt. of liquor from the nitrification zone which is fed back to the denitrification zone, are pref. adjusted such that nitrate is present in the liquor emerging from the denitrification zone. Process is esp. useful for treating effluent water with a relatively low content on nitrogen cpds., e.g. domestic effluents. The process ensures improved oxidn. of the organic cpds. present, which reduces the amt. of undesired anaerobic bacteria formed in the active sludge. This improves the sludge quality w.r.t. settling properties, so that faster settling is achieved and smaller settling tanks can be used.