Hidrológiai Közlöny 1971 (51. évfolyam)

1. szám - Varró István: Felszíni vizek tisztításának korszerű módszerei és anyagai

38 Hidrológiai Közlöny 1971. 1. sz. Special Conference Number, Szebellédy, L. retained on the carbon filter without adsorbing them. Consequently, they can be removed by water flushing. Obviously, still further research is necessary in this particular field. Activated carbon in powder from has been mentionod by P. L. Oirardot, in his paper entitled Charbon actif in No. 1, 1970 of "Techniques et Sciences Municipales et Revue de PEau", the activated carbon being used alone or in combination with ozone at major water works. Granulated activated carbon is preferred in somé instances on the consideration that it provides added safety. In Hungary powdered activated carbon is preferred in a form added to raw water mainly for improving taste and odour. Once the economie and efficient recovery of activated carbon is solved, the use of activated carbon filters may be expected to become more popular. The chances seem to be greater for the development of an adsorbent made of a stable plastic that can be used in eubstitution for activated carbon and that will be easier to recover. Materials similar to ion-exchangers offer possibilities in this respect. Clarifiers are critical structures in the treatment of surface waters. No mention is made here of rapid coagulation and filters under pressure. A wide variety of clarifiers has been developed and applied in practice. Their detailed discussion would be impossible, but a summarized evaluation seems permissible. The prerequisite of their efficient operation is a sound hydraulic design. Problems of this nature are studied intensively in various countries. The hydraulic design in called upon to ensure conditions promoting the process of coagulation and flocculation. Special care should be devoted to the uniform distribution of water both at the inlet and at the withdrawal. Secondary currents due to thermal and other processes should be minimized. In Hungárián practice somé of the sludge is recirculated to the clarifier. An improved method consists in using micro-sandparticles for increasing the weight of floccules. The same principle is utilized in the so-called "Cyclofiok" method permitting the flow velocity to be increased several times. Another operation of fundamental importance in surface water treatment is filtration. Several solutions are available for circulating water through the filter. Of these the downward-flow filters have found most widespread application. Encouraged by favourable experiences abroad, filter materials of different granulometry, quality and specific gravity are increasingly used alsó in Hungary where the filter layer is covered by an additional coarse-grained layer of anthracite. Filters of similar design permitted the load on the filter and the velocity of filtration to be inereased. Anthracite used as filter material in water treatment has been mentioned in several papers. Favourable results have been reported by F. Brummel in "Vom Wasser'- 1968 and R. H. Palmer in No. 11, 1968 of "Water and Sewage Works". Noteworthy attempts have alsó been made towards increasing several times the present filtration velocities and at the same time to improve the efficiency of treatment. Reference is made in this context to the DEVIG-type radial filter developed in Hungary and manufactured by VÍZGÉP, which proved successful in the treatment of surface water. A few remarks should be attached on the disinfection of water as well. It has been demonstrated that ozone is of a disinfecting effect, but this is of limited duration and does not extend to the distribution network. Chlorination, which has been applied with good results so far is still the most frequently adopted solution. It has been demonstrated, on the other hand, that slight amountsof chlorine added after ozone treatment will ensure a degree of disinfection meeting all relevant specification. Mention must be made here of the latest achievement of research, attained by using oxidized acetic acid (CHjCOOOH). This is claimed to have a bactericidal effects on about 360 strains of bacteria at very low concentrations of around 0,02 mg/litre. This brief introduction could not be extended to every phase and detail of water treatment technology. The objective was rather to indicate in broad outlines the scope of research activities and necessity for further action in the field of surface water treatment. A review of the papers submitted will be under taken in the conventional sequence adopted in water treatment: 1. Endrey, Gy. (Hungary): New method for the removal of iron and/or manganese and operational experience gained therewith. 2. Nóvák, Z. (Czechoslovakia): Removal of iron and manganese from groundwater by ozone treatment. 3. Starke, W. (Germán Democratic Republic): Filtering surface water on micro-mesh screens. 4. Bulkai, K. — Kőrös, Z. (Hungary): The clarification of cold waters. 5. Nyilassy, M. (Hungary): Improvement of clarification with materials of inorganic origin. 6. Nagy, G. (Hungary): Contemporary pretreatment and chemical preparation facilities at plants treating surface water. 7. Ourev, A. G. (Czechoslovakia): The zeta potential and its adjustment. 8. Zacek, L. (Czechoslovakia): The kinetics of coagulation processes. 9. Tesarik, I. (Czechoslovakia): Flow in sludge-blanket clarifiers. 10. Ivicsics, L. : Determination of the hydraulically correct design for clarifier basins. 11. íves, K. I. (United Kingdom): The role of theory in the advancement of rapid filtration technology. 12. Pálhidy, A. (Hungary): Treatment of water from the Eastern Main Canal for domestic purposes. 13. Varró, I. (Hungary): Treatment of surface waters by periodic chemical feed. 14. Varró, I.—Hembach, K. (Hungary). Treatment technology for water utilized across a small reservoir. 15. Hembach, K. — Bayer, A. (Hungary): Problems of economics and site selection in planning waterworks supplied by surface water. 16. Werner, G. (Germán Federal Republic): Trends in the development of treatment technology using chemicals with special regard to surface waters. \l.Bozzay, J. (Mrs.) (Hungary): Studies on the sludge material in vertical-flow contact sludge filters, the influence of sludge quality and volume on the quality of treated water. 18. Podhorsky, I. (Czechoslovakia): Increasing the hardness of water. 19. Cagnaux, A. (Switzerland): The M. D. process in drinking water treatment. 20. Horváth, I. (Hungary): Problems concerning mass transfer phenomena and reaction kinetics in ozone mixing reactors. 21. Kolin, L. )Hungary): The use of ozone for water treatment in Hungary. 22. Berger, K. (Switzerland): On the prolification of bacteria in the distribution network. 23. Marschall, K. (Austria): The disinfection of water using ozone. 24. Vasváry, L. (Mrs.) (Hungary): Considerations on the clorination of waters containing ammónia. 25. Valló, S. (Hungary): The application of contemporary water treatment methods in watersupply. 26. Oehler, K. E. (Germán Federel Republic):'Trends in the development of water treatment technology. Owing to their great number, the papers submitted can be discussed in a very brief manner only. The removal oí iron and manganese A new method for the removal of iron and manganese and the practical experiences gained with this method are described in the paper by Gy.