Hidrológiai Közlöny 1971 (51. évfolyam)
1. szám - Dr. Szebellédy Lászlóné: A vízminőség szerepe és változásai csővezetékekben
54 Hidrológiai Közlöny 1971. 1. sz. Special Conference Number, Szebellédy, L. Problems awaiting to be solved are due to the combined effect and interaction of chemical composition, microorganisms and bacteria, which especially at water works drawing on surface water, is the consequence of new kinds of polluting substances, originating from new products of the chemical industry. This is evidenced by the papers submitted, and the relevant literature alike. In Switzerland phosphate added to drinking water was found to cause a considerable increase of the bacteria count and is thus detrimental to the quality of drinking water in the network. For this reason the use of phosphate was prohibited in 1966, by the Swiss Federal Public Health Authority. However, the phosphate content of surface waters displays an increasing trend, resulting partly from fertilizers used in the catchment areas, partly from the growing popularity of detergents. In view of the fact that phosphates are not removed by present treatment technologies, this may entail serious consequences to the biological life in the network and mav raise the bacteria count appreciably. Mention must be made finally of a field largely neglected in the papers submitted, namelv the external pollution of network water. Quality may be affected for instance by aromatic hydrocarbons penetrating the wall of plastic pipe from the surrounding soil. Where plastic pipes are embedded in soil, contaminated with gasoline, gas or manurejuice, the possibility of taste complaints is not excluded. Defective seals in the network, may alsó cause pollution, through which bacteria or other harmfull substances may enter the water. Potential sources of pollution are alsó underground fire hydrants, but the entrance of polluting water or domestic refuse may have even graver consequences. Pollution may occur alsó where the pipe wall develops leaks due to corrosion. In such cases bacteria may enter not only as a result of depression, as frequently assumed, but alsó against the flow of water. The hazard of pollution exists not only in the distribution network and in the facilities of communal supply. In the Germán Federal Republic serious problems are due to facilities and equipment connected to the water mains in appartement-houses, schools, hospitals, shops and industrial plants. Drinking water may be polluted through these facilities and equipments by different substances. For instance the contents of washing machines, digesting tanks, disinfecting containers, gas- generators, chromium, gas, etc., may be drawn into the water mains. Similar cases often with fatal consequences have been reported repeatedly in the foreign literature. This danger is bound to become increasinglv severe with the increasing use of machines. It is believed that the problems related to the subject have been covered in the present report in the light of experience available both in Hungary and abroad. It would be mistaken, however, to assume that no new problems will arise—maybe in the near future already -since the growing menace to drinking water is closelv associated with the development of technology and the advances of civilization. Pariicipants of the Conference MÁi .Ma*
