Invertebraten im Trinkwasser

The drinking water quality has to be evaluated using chemical, physical toxicological and hygienic parameter, but increasing significance becomes the biological drinking water quality, because accumulation of particulate organic material within the drinking water tubes promote the development of small invertebrate as habitants of drinking water distribution systems. Since the end of the 90th an increasing development of water louse (Asellus aquaticus) occurred in drinking water distribution systems besides other microscopic small invertebrates, among else crustacean, worms and thecamoeba. Up to now, no standard methods as well as no simple and practicable sampling exist for the qualitative and quantitative determination of these animals in drinking water distribution systems. Within an interdisciplinary research project of the Berlin University of Technology, the Technical University of Dresden and the companies Aqualytis and Scheideler Verfahrenstechnik a sampling and analyzing system has been developed, which enable the gentle and quantitative separation of water louses, their feces and of other invertebrates using flushing of a water hydrant. Sampling, determination and evaluation of invertebrates in drinking water distribution systems has been develop and the occurrence of invertebrates was qualitative and quantitative analyzed using a multimetric evaluation index. It was demonstrated that feces of water louses are a good indicator for occurrence of water louses in a drinking water system. The investigations of different drinking water distribution system indicate that a high mass of deposited particles promotes a high population density of invertebrates. That’s why it is necessary to analyze the hydraulic conditions, the water distribution net structure and the sources of particulate material input and to calculate the expected accumulation of these particle using a dynamic water quality model for water distribution nets.