| 摘要 |
<p>The invention relates to a method for purifying nitrogen-containing waste water streams which arise, for example, in the food industry, the chemical industry etc. This purification method is characterized in that cycles are carried out which comprise the following steps: (a)supplying a first waste water influent to a reactor charged with nitrifying or denitrifying bacteria, respectively; (b) nitrifying by means of aerating the reactor contents; (c) supplying a second waste water influent to the reactor, so that reactor contents having a COD/NO3-N ratio >/= 4 are obtained; (d) carrying out a denitrification of the reactor contents; (e) nitrifying once more by means of aerating the reactor contents; (f) allowing the reactor contents to settle; and (g) draining part of the reactor contents as effluent. The method according to the invention is preferably carried out in the case of an industrial plant which involves a number of waste water streams of different compositions, one of the waste water streams having a high COD load and advantageously also a low Nkj-N level. The reduction in the nitrogen level of the untreated waste water stream(s) before purification can reach values of more than 95% in the process. <IMAGE></p> |
