Summary:

The article contains analysis and evaluation of the impact of clean sewage on sewage treatment plant in Myślenice, in the period 2008 - 201,1 on the physico-chemical composition and water quality of the receiver - river Raba. The analysis conducted based on collected and statistical research: amount and composition of clean sewage and composition of the water receiver in cross-section: Stróże (above of inflow clean sewage) and Osieczany (below of inflow clean sewage). The following pollution index were tested: total suspended solids, BOD5, CODCr, total nitrogen and total phosphorus. Based on obtained results its concluded that in period 2008 - 2011 sewage treatment plant was working properly, what explain quality of clean sewage. What reflected in directly protection of receiver water against pollution. Moreover, based on the results of U Mann Whitney test, concluded that in the both cross-section, composition of the water of Raba river was similar, what explain the results of this test, which didn't show statistically significant differences between average values of concentrations analyzed indicators of pollutions. Based on obtained results its concluded that sewage treatment plant in Myślenice doesn't negatively impact on quality of the water receiver -Raba river.