Detection and description of particles in drinking water

Particulate materials are undesirable in drinking water for both aesthetic (brown or 'rusty' discolouration) and hygienic reasons. Although some of these particles are not harmful to human health, others are either pathogenic microorganisms or nutrient sources for them, thus causing recontamination of drinking water. Water supply utilities are thus tasked to minimising particle loads in drinking water by optimised operation of their treatment plants. Detection of particulate substances in water usually relies on turbidity measurements. More detailed conclusions can be obtained by using particle counters that detect solids from 1 to 120 mu m in size relative to the overall volume. Studies conducted by us at several waterworks provided statements to the efficiency of particle retention and show that particle counter for individual measuring points are well suited to point out deficits and/or potentials for optimisation of drinking water treatment processes. Furthermore, our studies aimed to develop a method that permits quantitative estimates of particle loads in drinking water based on turbidity, particle number and particle size involving the use of micro-filtration units to identify traces of solids in water, because it is currently not possible to detect total solids in a routine test.