Although slow sand filters are effective in treating high-quality raw water, there are several limitations.
|Title||Evaluating modifications to slow sand filters|
|Publication Type||Journal Article|
|Year of Publication||1991|
|Authors||Collins, MR, Eighmy, TT, Malley, JP|
|Pagination||p. 62-70: 7 fig., 5 tab., photogr.|
|Keywords||activated carbon treatment, algae, design, efficiency, maintenance, ozonation, pilot plants, pretreatment, roughing filtration, slow sand filtration, trihalomethanes, turbidity removal|
Although slow sand filters are effective in treating high-quality raw water, there are several limitations. These include significant reductions in filter run lengths if raw water turbidity and algal content exceed relatively low levels, poor organic precursor removals, and relatively long filter cleaning downtimes and ripening periods. This article presents the following cost-effective modifications to enhance the performance of slow sand filters: roughing filters, filter mats, preozonation, surface amendment (i.e. anionic resins or granulated active carbon), and harrowing techniques that minimize filter downtimes. Although most of these modifications are based on pilot-scale evaluations, pilot results have been routinely and successfully extrapolated to full-scale operations.