ABSTRACT
Process design criteria have been established through extensive pilot plant testing in the US since 1965, and from operating experience since 1969. Rotational velocity affects wastewater treatment in several ways: it provides contact between the biomass and the wastewater, it aerates the wastewater, and it provides energy to thoroughly mix the wastewater in each stage. Wastewater temperature affects rotating contactor performance just as it does all biological wastewater treatment processes. The optimum tank volume determined when treating domestic wastewater up to 300 mg/l BOD is 0.12 gal/ft2, which takes into account wastewater displaced by the media and attached biomass. Nitrogen control has become a wastewater treatment requirement in many parts of the US In many eastern and midwestern states, nitrogen control requirements consist of ammonia nitrogen removal to reduce its oxygen demand on receiving waters. Wastewater temperatures below 55°F will affect nitrification efficiency with the rotating biological contactor process just as it will with all types of biological treatment.
