AWWA QTC97133

Invertebrate organisms occasionally become a nuisance to drinking water customers and must be dealt with by water suppliers. Although there are no indications that the invertebrates found in distribution systems of treatment plants that use groundwater in the Netherlands pose a threat to public health, their presence in 1988 and 1989 generated negative publicity. In order to collect more data on invertebrates in this type of drinking water, a two year survey of 36 distribution systems was conducted. This paper summarizes the results of this survey and reports the results, to date, of continued research on the effects and costs of two invertebrate control strategies: the distribution of biologically-stable drinking water (decreased nutrients), and periodic cleaning to remove invertebrates.