Effects of Periodically Reversing the Direction of Flow through an RBC

Research was conducted on two parallel, two-stage rotating biological contactor (RBC) pilot plants. The direction of flow through one of the pilot plants was periodically reversed (the first and second stages were reversed). The other pilot plant was operated in the conventional one-way flow configuration. For some combinations of loading and reversal period, periodic flow reversal produces significantly lower and less variable effluent soluble COD concentrations than does conventional one-way flow. For others there is no significant effect. It was observed that periodic flow reversal reduced the amount of nitrification that would otherwise occur.