The goal of the presented research works is to prove the following thesis: Does the process of contaminants reduction and effiuent application for arable land fertilization justify the treatment method of waste water from a yeast production facility in soil and plant environment. In order to achieve the above mentioned goal, basically the dynamics of physical and chemical properties change observed for waters, soils and plants irrigated with wastewater from yeast factory has been studied for many years. Part I presented the problems characteristics of production as well as water and wastewater management in the yeast factory, principles and technological effectiveness of the treatment of process wastewater from yeast production in soil - plant environment and impact of irrigation with wastewater on water purity. The research proved that very high biological treatment indices are achieved on the Silesian Yeast Factory fields where process wastewater is utilized i.e. concentration reduction for: BOD5 - 99.3% and COD - 99.7%, - for eutrophic compounds: N,0,.1 - 98.83%, P - 96.25% and K - 99.18%. The obtained percentage of concentration reduction is higher than the standards assumed in the water supply and wastewater discharge consent issued to the factory. The drainage water from the fields irrigated with yeast effluent is of I, II and III class of purity.

The goal of the presented research works was to prove the following thesis: Does the process of contaminants reduction and effluent application for arable land fertilization justify the treatment method of waste water from yeast production facility in soil and plant environment? In order to achieve the above mentioned goal, basically the dynamics of physical and chemical properties change observed for waters, soils and plants irrigated with wastewater from yeast factory has been studied for many years. Part II presents the problems connected with the impact of irrigation with wastewater from yeast factory on soil physical and chemical properties and on the quantity and quality of arable plants yield. Soils irrigated with process effluent from yeast factory show overfertilization with potassium. Also reduction of the organic carbon ratio to nitrogen is observed due to redundancy of potassium and deficit of organic carbon. Activities aimed at preventing reduction of organic substance consist in: straw, beet leaves and other solid organic waste ploughing. In industrial - grain crops rotation applied in the fields used for agricultural utilization of wastewater carried out in the research years of 1993-1997, an increase of yields (average for grain - by 13% and for root beet by 0.5-10.7%) was recorded. It was higher than in the case of yields produced on yeast production facility fields not irrigated with effluent and yields obtained by individual farmers from fields intensively treated only with mineral fertilizers. In comparison to the literature data the impact of irrigation with yeast effluent, the grain yields of winter wheat, spring barley and winter rape show slightly increased percentage contents of proteins, nitrogen, and potassium, whereas the contents of calcium and magnesium were smaller.