Vízügyi Közlemények, 1969 (51. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
(73) ute together about 2.2 tons/day to the polluting oil. The wastes of the capital, Budapest, carry about 27 tons of oil, i.e., ten times the foregoing figure, into the Danube. With the water leaving the country about 180 tons of oil are removed daily, i.e., a quantity comparable to the entering one. Observations along verticals have corroborated the assumption that high oil concentrations occur in the surface layers, while concentrations tend to decrease to a depth of 1 m and remain at a low, constant level at greater depths. This conclusion applies to all oil present in an emulsified form, whereas the total oil content depends on variations in the amount of suspended material. As demonstrated by the fluctuations in the oil concentration of samples taken from the same spot at different times, the polluting oil is discharged intermittently into the watercourse. These originate from the cleaning of tankers, flushing, or from other plants discharging into municipal sewers. During the observations in 1967 in a cross-section of the Danube downstream ol' Budapest the average ol' (Î0 samples was 3.4 mg/lit. The distribution ol oil content in the main current-line and along the banks is shown by the quality duration curve constructed on the basis of weekly observations in 1968. The higher degree ol pollution along the lefthand bank is clearly demonstrated by these curves. This could be traced back to a plant discharging oil-laden wastes and to the oil harbour. It can be demonstrated that samples representative lor the watercourse should preferably be taken from the main current line. Thermoanalytical —derivatograph — measurements have been used for identifying qualitatively the different oils. CONTEMPORARY TREATMENT OF INDUSTRIAL WASTES By E. Dobolyi, Gij. Mucsy, 1. Toókos ( Miss ) and L. Vermes (For the Hungarian text see pp. 378) During the past one-and-a-half decades industrial production grew by 20% per year, on the average, in Hungary. The volume of industrial wastes grew and will continue to grow parallel therewith. The problem ol' industrial wastes can be solved partly by measures within the plants, thus by using production technologies designed to reduce wastes, by rational water management, recirculation, efficient wastes treatment, etc. Under favourable geographical conditions I he wastes produced by several industrial operations may after suitable pretreatment — be treated together in a common treatment plant, which may be made especially economical by handling the domestic wastes from settlements at the same treatment plant. For the aforementioned reasons regional wastes treatment plants serving area units will in the future assume increased significance. For solving the problems of industrial wastes treatment it would he welcome, if individual branches of industry would, or commission an institute to develop the water householding and wastes treatment principles most suited for their particular needs, which principles and methods could then be adapted for solving the treatment problems of a particular plant. One of the prerequisites for good designing is the careful collection of basic criteria, accompanied by experimentation, since the wastes from particular plants may appreciably differ from data published in the literature. Some of the more important considerations are outlined subsequently, which should be observed when aiming at an efficient and economical design for treatment facilities in the food- and processing industry. The best conceivable way for the treatment and disposal of wastes in the food- and processing industry consists of agricultural utilization, which may involve considerable added benefits as well. An extensive review is presented of the problems associated with agricultural utilization, with special regard to the water-quality requirements to be met by industrial wastes for utilization in agriculture. 10 Vízügyi Közlemények
