Operational design and power economy of a rotating biological contactor

Abstract

A method to estimate power economy, defined as the amount of BOD removed per unit power consumption of the rotating biological contactor (RBC) was developed. The characteristic value of the power economy as a function of operating conditions was evaluated and discussed. While the power economy of RBC under practical operating conditions is much higher than that of the activated sludge process, the BOD removal rate of RBC per unit floor area is rather small, only about one-third of the latter in its practical use. This renders the RBC not well suited for use in large scale wastewater treatment, but rather only for small scale treatment where the floor area of the RBC is not an important factor to reckon with in the plant. Since the influent fluctuation of wastewater reduces considerable power economy, in order to keep its high value the use of a flow balancing tank with the RBC unit is recommended.