Current and progressive methods and techniques for drinking water treatment
Seminar
Seminar took place in Bešeňová, close to Liptovský Mikuláš, on November 20, 2007.
The program of the seminar was composed to reflect the needs and requirements of owners and operators of waterworks companies. It was composed to deal with the new information about the quality of ground and surface water from which ”the drinking water for the human needs” is prepared in accordance with the legislation. (Slovak government regulation no. 354/2006 Coll.)
Apart from lectures oriented to classical water tretament also other topics were presented. They were exactly prepared and completed with graphic information. They were addressed to new technologies, e.g. flotation by means of dissolved air which has been used in water treatment in Mostište na Morave in Czech republic since 2005. Thanks to this technology it is possible to remove toxic nostoc from the water which especially in the summer as the result of permanent enrichment of surface waters by nutrients (particularly phosphorus and nitrogen) cover the surface of waterworks reservoirs also in Slovakia. Also principles of membraned processes (low-pressure, high-pressure, nano – filtration and reverse osmosis were presented. They aroused the need to remove unwanted substances and microorganisms from the water (decomposition of nostoc, anaerobical decomposition of organic substances which influence ogranoleptical characteristics of the water, dissolving substances … ). Their implementation into waterworks technologies was enabled because of new materials (cellulose acetate, polyamides, ceramic alloys) which have become cheap because of their industrial production.
Lecture – water regulation in mountain environment “in situ” directed our attention to unused possibilities of this sophisticated and easy, as for the technological equipment, method. It can be used e.g. in water source (2 500 l/sec.) in Rusovce which is located near to Bratislava. This technology is frequently used in glacial moraines in Sweeden.
Advantages and disadvanates of the use of chlorine dioxide which do not hydrolyze and it stays in gaseous state were explained in lecture about health security of water during its transportation.
Lecture about dedicated to the UV radiation and ozone use which is frequently use in the process of modification, e.g. as oxidation agent and both technologies are used for health security of the water as the replacement of chlorine and its derivatives. These derivatives are together with some groups of organic substances suitable catalytic partner for the formation of harmful hologens and oxidative compounds (ethane derivative, methane, acetic acid ….) which are strictly not allowed in drinking water.
The importance of long-term monitoring was emphasized. It means that the quality of “raw water” has to be known. It defines the technology for regulation which presents in each waterworks company original process which also applies for health security of drinking water.
The problems of “hungry waters” – which consist of insufficient amount of calcium (<30 mg/l) and magnesium (<10 – 30 mg/l) were explained in the lecture which dealt with technological methods of recarbonization of drinking water. It also empahized the unwanted influences of undermineralized water – which has the bad influnce on consumers’ health. Statistics show that there is an increase of cardiovascular diseases in the areas where the ground and surface waters are not enough enriched by minerals because of the influence of undissolved crystalline and soil overlay. It happens mostly in the north and middle part of Slovakia.
One of the important topics was the regulation by means of active coal. This method is used to influence receptive features (smell, taste) of the water. Active coal filtration belongs to the final methonds of water regulation and is very often combined with sand filling filtration.
Three lectures from microbiological field were intentionally inserted into the program of the seminar in order to inform about infections of waterworks systems by pathogenic microorganisms.
First lecture dealt with cryptosporidium parvum a giardia lamblia that are resistant against commonly used disinfectant agent (UV radioation, granular coal filtration) and which thanks to favourable conditions causeed breakdown of water supply in waterworks systems (1993 Milwauakee v USA, 1998 Sydney). Contaminated water can cause disease of digestive system that can be lethal for older and ill people or for children.
Topic of the second lecture was problems of disposal of toxic products of cyanobacterium (microcystine). It occurs mainly in summer. It is located in colonies mainly on the lakes surface and creates so called nostoc flowers. It is big problem not only of drinking water but also of water used for recretation. The amount of 1 µg of microcystine can endanger the people’s health and in such case the way of supplying of drinking water has to be secured from different sources of water. Microcystines cause allergies, weakness or liver diseases. Importance of this topic is strengthen by the occurence of nostoc flower also in slovak reservoirs.
Last lecture dealt with inactivation of different groups of microorganisms. During the germicide of drinking water by using of disinfectant agents we assumed the existence of pathological micro and macro-organisms.
One of the lectures dealt with the quality changes of drinking water during its treatment and transportation from its source to the customers and impacts which influence quality of drinking water. This lecture was a summary of many topics read at this conference. Lecture points out what causes the problems. We should be aware of these problems because drinking water is qualitatively unstable liquid and very sensitive as for the chemical, biological and microbilological point of view. In the process of citizenship supply of drinking water it requires professional management and operation. Periodical cleaning of whole system should be inseparable part of that process because drinking water is our most frequent “food”.
Seminar was attended by more than 50 represenatives of waterworks companies and representatives of Ministry of environment of Slovak republic. The main goal of this seminar was to provide the information about modern technologies and problems which influence the quality of surface water. As well as to inform the waterworks companies’ management about scientific and professional workplaces and about experts who can help with the solution of the problems of the health security of the drinking water during its transportation and distribution to the customers.
Pavol Helia
Specialist Assistance for Slovak Regional Water Companies
Activities carried out as part of the project
Activities under preparation