The article presents results of analysis and their discussion concerning operation of sewage from butchery of pigs pretreatment plant in Gruszów in Pałecznica commune. Additionally, construction of the mentioned pretreatment plant was discussed, for authors of its idea and project are Ph.D. eng. Marian Długosz and Ph.D. eng. Piotr Bugajski. The aim was to solve three problems: to regulate high disproportion of outflowing sewage, to reduce amount of pollutants contained in sewage and to prevent them from rotting. The research included regulation of sewage outflow put evenly in time, physicochemical analysis (BOD5 and COD) of sewage before and after pretreatment plant and measurements of oxygen amount in outflowing sewage. The first object on the technological way is well with the sieve for solid parts, in which pollutants bigger than 5,0 mm are stopped. Next, sewage flows into the settling tank, in which inflammable pollutants sediment to the bottom, and afterwards sewage flows to the aeration chamber. In this chamber, process of sewage aeration (oxygenation) occurs. Oxygenated sewage flow into the grease trap, and next into the well, in which sewage separation occurs. Part of them goes into the living sewerage system, and next to the Bioblok PS-50 sewage treatment plant, ...
