Biological purificn. of waste water, esp. domestic - using oxidn. stage then decantation and nitrification stage

摘要

The process comprises, opt. after a primary decantation, a first oxidn. phase in an aerated medium of a substantial part of the organic materials followed by an intermediate decantation and then a second nitrification phase of a substantial part of the nitrogeneous materials. The process is characterised by the fact that (i) the nitrification is carried out on at least one bacterial support, (ii) as a function of the max. BOD5 concn. B at the end of nitrification, the max. concn. A at the start of this stage is determined such that B is 0.35A+9 is satisfied, that for a value of A below 100 mg/l and a BOD5 charge at the nitrification stage of at most 6g/m2/day; (iii) the dimension of the bacterial support is determined from the BOD5 charge x and the nitrification charge y to satisfy the approx. relation y10=-0.25+0.5, x being from 1-4g/m2/day and the ambient temp. 10 degrees C; the correction for a temp. circled negative being y circled negative=0.212.1.0725 circled negative-1o.y1o. The process enables a greater efficiency at both stages and lower plant costs.