Summary:

The paper presents the results of the analyses of the distinctive household sewage inflows frequency to the type Eko-Clear/II sewage treatment plant located in Tęgoborza. The objective sewage treatment plant was designed to receive sew-age from 1630 ENI. The designed average daily sewage inflow Qd.av. equals 204 m3•d-1. The results were analyzed on the basis of the daily read of the inflowing sewage in the 5 years' period 2002-2006. Each year the range of the incoming sewage was described and the frequency of the maximum inflows, exceeding the treatment plant's admissible loads, was discussed. The sewage treatment plant during the research was hydraulically underloaded. In 2002 less than 32% Qd.av. flowed into the treatment plant, in 2003 this amount increased to about 42% Qd.av. In the next year - 2004 the highest inflow was found in the tested period, which was over 49% of the designed inflow of sewage. In next two years the amount of incoming sewage decreased in comparison with the previous years. In 2005 the in-flow balanced around 41%, whereas in 2006 less than 35% Qd.av flowed into the treatment plant. In 2002 the most frequent inflows ranged between 40 m3•d-1 and 60 m3•d-1 or 60 m3•d-1 and 80 m3•d-1. In the next year, 2003 the inflows balanced in the same ranges. The most frequent inflow ranges in 2004 were: 60 m3•d-1 -
80 m3•d-1 and 80 m3•d-1 - 100 m3•d-1. In 2005, similarly to the previous year, the majority of the average daily sewage inflows balanced in the same ranges. The most stable sewage inflow was found in 2006. Sewage inflow from 5 different classes was on the similar level of frequency. With exception for the year 2002, some inflows were a few times higher than the average inflow. These were inflows which exceeded 200 m3•d-1, and in 2006 even 300 m3•d-1. Such inflows occurred during huge precipitation. This indicated high amount of the accidental water flowing into the sewerage system.