Charakterystyka jakościowa ścieków powstających w browarach i słodowniach

Beer is the fifth most popular drink all over the world. Annual consumption reaches 23 L per capita. In Poland, the brewery industry has been the subject of intensive transformations in the last 20 years as a result of, most of all, an increase in beer consumption and brewery wastewater quantity increase are observed. Two main cycles may be distinguished in the beer production process: production of malt and production of beer. Wastewaters are generated at all production stages: soaking and transport of grain (malt house), spent grain anddraff (brewhouse), yeast washing and waste yeast pressing (fermentation house), and mainly from processes of production appliances, rooms and packages cleaning. Hence, the quantity of generated wastewaters is significantly affected by the washing technology of appliances and installations. The study presents the physicochemical characteristics of wastewaters originated from the brewery plant production departments. Wastewater samples were taken from two brewery plants (BP) 1 and 2. They produce lager type beer. The mean water consumption in the breweries in the study period reached 0.30 and 0.45 m3 hL-1 of produced beer respectively for BP1 and for BP2. Wastewaters originated from: brewhouse, the process of spinning (centrifuge), fermentation house (fermentation tanks, horizontal unitanksUT), storage facilities (with facilities for filtration, storage in the pressurized tanks BBT type) and racking house – BP1 and frommalt house, brewhouse, fermentation house and racking house at BP2. In addition, analyses were conducted on a mixture of wastewaters originating from the whole brewery plant that, apart from the above-mentioned production wastewaters, contained wastewaters from social facilities and administrative buildings.Physicochemical analysesincluded: pH, suspended solids, total nitrogen, total phosphorus, COD and BOD. Results of the study demonstrate a correlation between the site of wastewaters generation, specific character of a unitary technological process and the quality of wastewaters discharged to a sewage system, including their potential biodegradability. The highest average concentration of organic compounds (COD and BOD) (28161 mg O2 ∙ L-1 and 13595 mg O2 ∙ L-1) and total phosphorus (75,2 mg P ∙ L-1 )were observed in the effluents produced during the centrifuge process at the brew house. Wastewater from brewhouse located at BP1 characterized by the highest suspended solids concentration (924 mg d.m. L-1). The maximum values of total nitrogen (132,9 mg N ∙ L-1)were reported in the effluent from the fermentation process (BP2).Despite significant differences in the quality of wastewaters, they were characterized by the C:N:P ratio beneficial for the biological treatment, irrespective of the source of their origin.Ratios of BOD : (TKN + TP) (>25)in brewery wastewaters indicate the potential for highly-effective process of biological N and P removal. These ratios show that the processes of denitrification and biological phosphorus removal should not be limited by the availability of the organic substrate. Moreover, most examined brewery wastewater streams can be applied as external carbon source in biological processes removal of nitrogen and phosphorus from wastewater containing insufficient amounts of biodegradable organic matter.