Desinfektionsverfahren in der Schwimmbeckenwasseraufbereitung unter besonderer Berücksichtigung des Elektrochemischen-Aktivierungs-Verfahrens zwecks Verbesserung der Beckenwasserqualität

Abstract

The principal aim of the study was the detailed survey of swimming pool water disinfection by application of the ECA-technologis (electrochemical-activation), a significant water quality improvement seen from chemical point of view was expected. Instead of delivering gaseous chlorine into swimming pools, here the disinfectant was produced by electrolysis of a dilute NaCl-solution in situ. The "hygienic parameters" represented the crucial control parameters of the investigation. During the experimental run of ECA process extremely small microbial colony numbers (1-40 per mL) were observed after several days. Escherichia coli, coliforme bacteria and Pseudomonas aeruginosa could not determined in all tests. The other central parameters for the efficiency of the disinfecting process, the redox-voltage, could not be maintained (710 - 757 mV) during the entire experimental process with the ECA above the threshold of 770 mV (pH 7,4-7,6) required by the regulations DIN 19643. The "hygienic auxiliary parameters" in DIN 19643 could be maintained by the use of conventional chlorine, because other disinfectants in DIN 19643 were not allowed. An intended significant reduction of the "Bound C-chlorine" values, that give an indication of the total chloramines - as the typical disinfection by products - content could not be achieved. This observation is supported by the observation of other disinfection by-products (DPB) carried out in parallel. The observed concentrations of trihalomethanes were below the threshold value of 20 µg/L. Presently the investigation carried out here with ECA as compared with conventional chlorine-disinfection under identical well defined conditions, resulted in no significant reduction of the trihalomethanes. A subsequent UV-light irridation of swimming pool water gave a significant reduction of "Bound Chlorine" (chloroamines) of about 24 %, where only 65 % of pool water passed the UV reactor chamber.