Hidrológiai Közlöny 1971 (51. évfolyam)

1. szám - Dr. Öllős Géza: A 2. Vízminőségi és Víztechnológiai Kongresszus összefoglalása

Soccial Conference Number, Öllős, G. Hidrológiai Közlöny 1971. 1. sz. 61 therefore very welcome and worthv of being remembered. Cooperation from them is expected in the future even more than in the past. 7. When reviewing the development of treatment technology, there seems to be increasing interest —as evidenced alsó during this Conference—in the more sopliisticated technologies. There appears to be no possibility, neither now, nor in the future, for the development of a generally applicable technology. The backbone of the technological process must be determined on the basis of the particular properties of the given raw water. This backbone may consist of — rapid filtration, or if a higher degree of treatment is desired, — slow filtration, — ozone treatment, — activated carbon treatment, etc., or a combination of the above methods. The most expedient technology is sometimes difficult to determine. The reason for this hes frequentlv in the fact—as regards both technology and economics—that the operations preceding any particular stage of treatment technology, which may be regarded as pretreatment, are of poor efficiency. No stage in the treatment technology must be expected to yield more than ensured by the pretreatment required for its functioning, or than it is capable of performing in view of its mechanical, chemical, or biological character. In this respect — micro filters, — slow filtration, — systems with filter materials offering high adsorption, effeets, — ozone treatment, and in generál the methods of treatment ensuring a higher degree of oxidation may be expected to be adopted more widely. While appreciating without reservation the increasing importance of slow filtration, it should be remembered alsó that it would be mistaken to advocate this method in every instance, since there is mostly an alternative method, or a combination of alternative processes capable of ensuring practically the same degree of treatment. Any decision must be based necessarily on the careful consideration of polluting components present in the particular raw water and on detailed economic estimates. The relatíve merits of using surface, or bankfiltration water and in generál subsurface waters, have been repeatedly mentioned during the Conference sessions. The conclusion adopted appears to be a clear one: in many countries areas exist, where rehance can and must be made on groundwater resources in the future. In such cases the use of groundwater should be promoted in the future if this is economically advantageous and if no pollution is likely to reach the subsurface supplies. In other instances, where groundwater resources are insufficient, or not of the desired quality, resulting in uneconomical use, the development should be directed obviously towards the exploitation of surface waters. Decisions should be based invariably on careful research and reliable data, with due consideration to local, or régiónál conditions. 8. The emphasis on the necessitv of pilot-plant experiments is noted with satisfaction. This is the way which when followed may lead to a philosophy shared by the researcher, designer and operator alike, to a mutual understanding and improved relations, since often otherwise controversial issues can be replaced by a more reliable design philosophy supported by actual data. Great care should be devoted, however, to the use of suitable instrumentation, observation techniques and the unbiased interpretation of observation data. 9. Model tests continue to play an important role. It is interesting to note in this respect that advances in instrument techniques make alsó the study of more involved phenomena and processes possible. The field of model tests is observed to expand. For example, in recent times model tests were used successfully for determining flow conditions in major reservoirs, e.g. those surrounded by ring dikes, contributing thus to the development of a unified dynamic system, coordinating the location and method of inflow and outflow, further the spatial flow pattern between these two points. As indicated by these examples model tests can and should be used more confidently. The more widespread application of model testing is hoped to improve alsó the hydraulically correct design and arrangement of major storage basins incorporated in the distribution system. This applies to the flow of water in the basin and to that of air above the watersurface alike. 10. It was alsó noted with satisfaction during the Conference sessions that the principle of operative measures was advocated repeatedly. Operating experience is now readily accessible, making the determination of adverse conditions and situations possible and indicating usually the potential remedies thereof. Moreover, the necessary research objectives can alsó more clearly defined. The premeditated control of self purification in rivers, lakes and reservoirs (by preliminary storage, aeration, etc.) may be offered as an example to the point. In fact, this may be lookecl upon as a special interpretation of water management in the interest of water supply. Remembering the large number of shallow storage reservoirs in Hungary, and looking at them as relatively economical sources of supply, the principle of operative control deserves special attention for many cases of their operation. A less conservative, more operative approach to reservoir planning and design is usually made a priori imperative by the needs of agriculture as an environmental factor. 11. Problems concerning the weight and reliability of a variety of observation data were alsó raised with added emphasis during the Conference. This is logical, as it is actually not the number of