White Paper: Enhancing The Performance Of Oxidation Ditches

By Larry Moore

Oxidation ditches are very popular wastewater treatment processes for small to medium sized municipalities that have to meet stringent water quality standards. Some oxidation ditches have old, poorly performing fixed brush aerators, which provide poor mixing and poor oxygen transfer. Most oxidation ditches are designed to achieve CBOD removal and nitrification. However, many NPDES permits may become more restrictive in the future with respect to the discharge of total nitrogen or total inorganic nitrogen. Therefore, modifying oxidation ditches to include an anoxic zone to achieve de-nitrification is an excellent way to meet the more stringent discharge standards. This paper discusses the specifics of enhancing nitrogen removal by establishing an anoxic zone.