The impact of step-feed on COD and BOD5 removal in rotating biological contactors

Ayoub, G., Saikaly, P., El-Fadel, M. and Baydoun, E. (2004) The impact of step-feed on COD and BOD5 removal in rotating biological contactors. Environmental Engineering Science, 21, (5), 558-568. (doi:10.1089/ees.2004.21.558).


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A study was conducted to evaluate the effectiveness of step-feed in a rotating biological contactor (RBC) system consisting of two three-stage units (one control and one step-feed) treating synthetic wastewater. The performance of the system was evaluated in terms of organic rates, applied and removed. The impact on sCOD, sBOD5 removals, and stage-dissolved oxygen (DO) conditions over a range of hydraulic and organic loading rates (HLR = 0.032 to 0.125 m3/m2·day and OLR = 11.03 to 111.6 g sCOD/m2·day) was evaluated. The results indicate a linear relationship with excellent correlation between the organic loading and removal rates. Varying the HLR and the substrate concentration within the tested range had negligible effect on the removal efficiency of the process. Similarly, the overall removal efficiency with varying OLR showed very limited improvement except at the highest OLR tested (111.6 g sCOD/m2·day) where removal increased by 5.2 and 2.4% for COD and BOD5, respectively. Increasing the HLR and the OLR resulted in a decrease in DO in all the stages of the two units. However, DO values in the step-feed system were higher than those recorded for the control system. In addition, O2 limiting conditions (DO < 2 mg/L) and heavy bacterial mass growth and possible growth of Beggiatoa were detected in the first stage of the control at high loading rates

Item Type: Article
Digital Object Identifier (DOI): doi:10.1089/ees.2004.21.558
ISSNs: 1092-8758 (print)
Related URLs:
Subjects: Q Science > Q Science (General)
T Technology > TA Engineering (General). Civil engineering (General)
Divisions : University Structure - Pre August 2011 > School of Civil Engineering and the Environment
ePrint ID: 52889
Accepted Date and Publication Date:
1 September 2004Published
Date Deposited: 15 Jul 2008
Last Modified: 31 Mar 2016 12:31

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