Summary:

The paper analyzes the variability of sewage inflow to a treatment plant in Dębica. For this purpose, the following basic descriptive statistics of the sewage inflow to the treatment plant were determined: mean value (Qdm), median (Mo), minimum value (Qdmin), maximum value (Qdmax), standard deviation (), coefficient of variation (Vzm), range (Ro). Histogram of a number of sewage inflows to the treatment plant for the specified observation intervals was determined. Detailed diurnal raw sewage inflows to the treatment plant in Dębica were summarized for the period of 2009-2015 compared to the limit value specified by the water-legal permit and the to the mean value. Mean diurnal sewage flow values for individual months from the period of 2009-2015 were also summarized. Mean diurnal sewage flows in individual years of the studied period, as well as mean diurnal sewage flow values in each day of the week were compared. Moreover, runoff data were obtained from the Tarnów station (the nearest rainfall station to the studied facility) and on this basis mean values of diurnal precipitation for individual months in the period of 2009-2015 were determined. Subsequently, the days of the study period were divided into 7 major groups based on the amount of atmospheric precipitation. The effect of precipitation on the amount of sewage flowing into the studied facility was examined and it was found that the precipitation has a significant effect on the sewage inflow to the treatment plant in Dębica.