page_title: Rotating biological contactor
section_title: History
hierarchical_section_title: Rotating biological contactor / History
caption_attribution_description: English: KLARGESTER's (Now Kee Process Ltd) First Domestic RBC (with the lid off) Fresh out of the Factory in 1955.
context_page_description: A rotating biological contactor or RBC is a biological fixed-film treatment process used in the treatment of wastewater following primary treatment. The primary treatment process involves removal of grit, sand and coarse suspended material through a screening process, followed by a process of settling of Suspended Solids. The RBC process allows the wastewater to come in contact with a biological film in order to remove pollutants in the wastewater before discharge of the treated wastewater to the environment, usually a body of water. A rotating biological contactor is a type of secondary treatment process. It consists of a series of closely spaced, parallel discs mounted on a rotating shaft which is supported just above the surface of the waste water. Microorganisms grow on the surface of the discs where biological degradation of the wastewater pollutants takes place.
context_section_description: The first RBC was installed in West Germany in 1959, later it was introduced in the United States and Canada. In the United States, rotating biological contactors are used for industries producing wastewaters high in biochemical oxygen demand (BOD) (e.g., petroleum industry and dairy industry). In the UK, the first GRP RBC's - manufactured by KEE Process Ltd. originally known as KLARGESTER - go back to 1955. 
  A properly designed RBC produced a very high quality final effluent. However both the organic and hydraulic loading had to be addressed in the design phase. 
  In the 1980s problems were encountered in the USA prompting the Environmental Agency to commission a number of reports.
  These reports identified a number of issues and criticized the RBC process. One author suggested that since manufacturers were aware of the problem, the problems would be resolved and suggested that design engineers should specify a long life.
  However, this was only possible when the manufacturers became aware of the design problems and the stress to ensure a long life and since failures still occurred it was unlikely any design stresses were known.
  Severn Trent Water Ltd, a large UK Water Company based in the Midlands, employed RBCs as the preferred process for their small works which amount to over 700 sites  Consequently, long life was essential to compliance.
  This issue was successfully addressed by Eric Findlay C Eng when he was employed by Severn Trent Water Ltd in the UK following a period of failure of a number of plants. As a result, the issue of short life failure became fully understood in the early 1990s when the correct process and hydraulic issues had been identified to produce a high quality nitrified effluent. 
  
  There are several other papers which address the whole issue of RBCs.
  Findlay also developed a system for repairing defective RBCs enabling shaft and frame life to be extended up to 30 years based on the Cranfield designed frame. Where additional capacity was required intermediate  frames are used maximising minimising the need for duplication
caption: KLARGESTER GRP RBC from 1955
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