Summary:

The aim of the study was analysis of the reliability of the municipal sewage treatment plant Bioblok PS -50. The sewage treatment plant is in Gruszow in municipality Palecznica in the Malopolska province. Time of research was from 2008 to 2010 year. During this period, collected and analyzed the physico- chemical 18 samples of raw sewage and treated with an average frequency of once every two months in accordance with the reference methods. The evaluation of the effectiveness of contaminant removal in this treatment was determined using the Weibull reliability theory elements. The studies included pollution indicators specified in the authorization issued of law for this object: BOD5, COD and total suspension. Moreover determined regarding the reliability of wastewater nitrogen. On the basis of the assessment of the reliability of operation of the facility in relation to the indicators of the primary group: BOD5, COD and total suspension has been shown that the probability of exceeding the limit values can be from 3 to 8 days in the year. Number of days with possible exceeding of the limit values of indicators of pollution indicates that the test treatment meets the level of technological reliability. With respect to the reliability of the nitrogen compounds in the waste water treatment test states that the probability of exceeding the limit value is possible in 12 days of the time period of one year.