The NCHC process is suitable for all waste waters with high nitrogen concentrations and low BSB5 content such as e.g.: landfill leachates, highly polluted component currents from sewage plants or process water from the treatment of biological waste. This innovative NCHC process is based on the biological conversion of ammonium and nitrite into atmospheric nitrogen, a process that only takes place in the absence of oxygen. This so-called anaerobic ammonium oxidation takes place in solid-phase activated carbon inoculated with correspondingly specialised strains of bacteria. Partial oxidation of ammonium in the course of shortened nitrification is required (nitritation) in an upstream step since the waste water to be treated usually contains no or only very little nitrite. The use of the NCHC process thus permits extensive elimination of ammonium nitrogen with complete omission of the denitrification required in conventional process concepts. This means external carbon sources can be dispensed with to a great extent and, as a direct consequence, there is a clear reduction in excess sludge production. Combined with the lower energy requirement (decreased oxygenation capacity), this then results in a great decrease in operating costs for the plant operator.
