Translations:Wasseraufbereitung und Grauwassernutzung/886/en

In addition to the oxygen consumption for BOD degradation, the oxidation of nitrogen from ammonium NH4 to nitrate NO3 is to be considered. This increases the required amount of air depending on the nitrogen content in the reuse water (approx. 10 mg N/L with greywater). With greywater this leads to three times the amount of oxygen required, approx. 30 mg/L. Normally the water is not continuously distributed throughout the day in reuse systems Therefore it must be ensured that the packing bed receives sufficient time (> 2 h) after loading to reduce pollution. During this period, the clean water should not be drawn from discontinuous system, because otherwise it may lead to increased COD/BOD₅.