Rotating Biological Contact (RBC) treatment systems were developed concurrently with new plastic trickling filter media in the 1960s. An RBC system consists of a series of polystyrene or polyvinyl chloride discs that are partially submerged in wastewater and rotated on a horizontal shaft. As with all fixed film system, RBC units are loaded based upon kg substrate per square meter of surface area.
Early RBC systems had problems with structural failure (mainly shafts). However most of these problems have been addressed and modern RBC systems do not have these problems. Most installations have multiple RBCs in stages that treat soluble BOD before going to separate nutrient removal sections.
Often we see RBCs used in conjunction with a conventional suspended growth system. The RBC can serve as a roughing filter to reduce soluble BOD prior to the suspended growth system. Most commonly, we have an RBC after the suspended growth system to remove ammonia via biological ammonia oxidation (nitrification) where a fixed film system has greater stability than a suspended biological process.
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
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