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The effect of oxidation on filtered water turbidity and particle counts is being investigated as part of AWWA Research Foundation Project 2725 -- "The Use of Oxidants to Minimize the Passage of Pathogenic Particles Through Granular Media Filters - Mechanisms and Development of Design and Operating Criteria". The results indicate that filtered water particle counts can be lowered by as much as an order of magnitude compared to the "no oxidant" case when chlorine, ozone, or chlorine dioxide are used as pre- or intermediate oxidants. Potassium permanganate also reduced filtered water particle counts, but the effect was less dramatic (about a 50% reduction). Corresponding significant improvements in turbidity removal were not noted - filtered water turbidities were less than 0.1 ntu in all cases (that is, with and without oxidant addition). However, a slight improvement in filtered water turbidity was observed in most experiments when an oxidant was used. The observed beneficial results were not a function of oxidant dose at the dosages tested. Instead, the application of an oxidant was an all or none effect; improved water quality occurred when an oxidant was added regardless of dose. It is recommended that utilities always practice pre- or intermediate oxidation. Includes 9 references, figures.

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Edition: Vol. - No. Published: 11/01/2002 Number of Pages: 8File Size: 1 file , 420 KB