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EVALUATION OF FULL-SCALE TERTIARY WASTEWATER FILTERS
Citation:
FitzPatrick, J. AND C. Swanson. EVALUATION OF FULL-SCALE TERTIARY WASTEWATER FILTERS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-80/005.
Description:
Conventional methods for treatment of municipal wastewaters frequently produced effluents that will not meet local discharge requirements. Granular media filters are being installed to provide teritary treatment for increased removals of suspended solids and BOD. This report provides performance data for full-scale tertiary filters from eight treatment plants and discusses effects of various design and operating practices. Semi-empirical mathematical models in the report relate filter clarification efficiency to characteristics of secondary effluent particulate matter and to filter operating parameters. The models developed in this study may be applied with some caution to predict filter suspended solids removal or clarification efficiency without pilot-scale tests. An important design consideration for small scale tertiary wastewater filters was found to be the ability to handle shock loads caused by secondary process upsets. This consideration generally favors those designs with slow rate of headloss development. Clarification efficiency is only weakly dependent on filter media depth and media grain size. Better correlations of filter clarification efficiency have been obtained for grab compared to composite sample data. Composite process variables generally fit a log normal distribution best and normal distribution second best.