BIOLOGICAL NUTRIENT REMOVAL IN THE PHOREDOX PROCESS.

In areas where eutrophication of receiving waters is causing concern it is important that one of the major sources of nutrients, namely municipal wastewater treatment works, should receive particular attention. The selection of a process capable of producing an acceptable effluent quality from such waters, while remaining economically competitive, is the uneasy task of the design engineer. The phoredox process is generally effluent without the use of chemicals, subject to the presence of sufficient biodegradable organics in the feed, and the provision of adequate anaerobic and primary anoxic retention time. The development and application of a five-stage activated sludge treatment sequence of nutrient control in the South African municipal sewage treatment field is discussed in this article.