Characterization of suspended particles and deposits in drinking water reservoirs

Suspended particles transported by drinking water were examined to understand their role in deposit accumulation and colonization in pilot and full-scale reservoirs. No pesticides were detected in the deposits but several PAH were identified. Deposits accumulated at a rate of 8 μg/cm²/day (29 g/m²/year) over a five month period. Quartz, feldspar, and amorphous iron were characterized in reservoir sediments. Sedimentation of suspended particles, mainly those composed of organic (biological) matter, was incomplete, and was not a key factor governing bacterial accumulation in the deposits (10⁴ to 10⁵ CFU/ cm²). Thus, limiting bacterial nutrients - dissolved organic matter - in treated water should be the only way to control the extent of bacterial colonization of deposits.