AWWA JAW34922

The size of the filters used in a water treatment pilot study has a big impact on the cost of the pilot facility itself. It has been shown that errors can be avoided by maintaining an adequate ratio between filter column diameter and media diameter (D/d). The purpose of this study was to investigate the effect of this same scaleup parameter on the filtration process itself. Five pilot-filter columns were operated in parallel with a full-scale filter. In these tests, (D/d) ranged from 26:1 for the smallest column to 6,000:1 for the full-scale filter. No significant differences were observed in the mean rate of head loss buildup, the effluent turbidity, or the effluent particle count for any of the filters, although the variance in the estimate of rate of head buildup was much greater for the smallest filter. A D/d ratio of 50 or greater is recommended for most pilot-filter operations. Includes 24 references, tables, figures.