The aim of the study was to determine the extent to which heavy rainfall, that occurred in 2010, affected the infiltration into the selected sewage treatment plants in the Małopolskie voivodeship. The research was conducted in four separate sewer systems, located in poviats adjacent to the city of Kraków, dis-charging sewage to mechanical-biological treatment plants with a capacity below 1000 m3•d-1. The amount of sewage and extraneous water in the average wet year (2008) were used as control.As a result of heavy precipitation in 2010 the sewer system A received 18 539 m3 more extraneous water than in 2008 (increase by 343%), the sewer sys-tem B - 22 822 m3 (increase by 163%), the sewer system C - 109 715 m3 (increase by 248%) and the sewer system D - 30 796 m3 (increase by 303%). Heavy precipitation in 2010 caused the increase of infiltration and inflow by 264% on average in all studied sewer systems compared to the average wet year. As the result of precipitation, whose annual total in 2010 was higher by 65% than the normal value in 2008, there was an increase in the annual share of extraneous water from 5.3 to 19.7% depending on the ...
The research aimed to learn if and to what extent extraneous waters, occasionally flowing into sanitary sewer system during atmospheric precipitation, change proportions of selected pollution indices which are significant regarding biological sewage treatment. The following proportions between pollution indices should be maintained in the sewage subjected to biological treatment process: COD:BOD5 ≤ 1.8; BOD5:N ≥ 4.0, BOD5:P ≥ 25; COD:P ≥ 3.6. Investigations conducted in two sewer systems located in the Małopolskie voivodeship revealed that extraneous waters infiltrating the intercepting sewers during wet weather negatively affect all proportions between pollution indices. Increasing amount of extraneous waters in sewer systems caused the greatest changes of BOD5:N and BOD5:P proportions. On the basis of conducted research it was found that considerable quantities of nitrogen and phosphorus compounds are supplied to the sewer system with extraneous waters, which in biological denitrification and dephosphatation processes may lead to a deficit of organic compounds causing a necessity to provide an external source of carbon for the reactor chambers, such as methanol, ethanol, acetic acid, glucose or others. During the conducted investigations it was demonstrated that extraneous waters in interceptors cause not only sewage dilution, but also significantly change its chemical composition. ...
The objective of this research was to compare the amount of extraneous water flowing into selected gravitational separate sewer systems which discharge domestic sewage from the settlement of single-family houses in Poland and France during a year with a standard annual amount of precipitation. The study included a total of four sewer systems, including two operating in Poland and discharging the sewage from settlements near Krakow in the Malopolska Province and two systems operating in France and discharging the sewage from settlements of single-family houses near Lorient, Brittany, Morbihan Department. As part of the analysis, an average daily tributaries of extraneous water into sewers under the research, values of addition and share of this water were compared. Analysis of the research results demonstrated that the hydraulic load of sewer systems with extraneous water does not depend on the age of the sewer system, but mainly on the number of house drains, and to a lesser extent its length. It was also determined that the average daily amount of extraneous water flowing into sanitary sewer systems in wet weather is 0,107 m3·d-1 per 1 sewer connection. The study showed that tributaries of extraneous water into the separate sewer system ...
The aim of this study was to assess the reliability of two on-site sewage treatment facilities (BCT S-12 and TJ EP-4) serving two school buildings located in rural communes in Małopolska region. The reliability was determined using Weibull reliability method. The research was conducted for 24 months and it involved the collection and analysis of 48 samples of raw and treated sewage from each facility. The analyses included organic and biogenic pollution, i.e. BOD5, COD, and total nitrogen. Reliability assessment revealed the following effectiveness for BCT S-12 facility: 77% for BOD5, 96% for COD and 25% for total nitrogen. For TJ EP-4 facility, the effectiveness was 81%, 88% and 72% for BOD5, COD and total nitrogen, respectively. Both facilities used the activated sludge process and experienced periodic disturbances in the treatment flow that resulted in reduced sewage treatment efficiency. Considering the above, the processes of nitrification and denitrification in the biological reactor should be streamlined to provide more effective removal of organic and nitrogen-based compounds in the investigated facilities. ...
The two-stage technological system for the treatment of domestic sewage, characterized by an elevated concentration of ammonium nitrogen, consisted of a settling tank and a vertical flow multi-layer filter bed with a sponge-sand filling was analyzed. In the upper part of the filling in the form of spongy polyurethane foams there was the removal of hardly decomposable organic compounds and ammonium nitrogen without the need for additional aeration. In the lower layer of quartz sand, the removal of orthophosphates and pathogenic bacteria took place. After 400 days of operation, multi-layered filter beds achieved high average removal efficiency under variable hydraulic load conditions. The upper 30 cm layer of waste foams used, combined with the 60-cm bottom layer of sand, proved to be very effective in the removal of ammonium nitrogen and organic compounds. The degree of N-NH-4+, CODCr and BOD5 elimination was at 91.6, 77.4 and 91.7% respectively. The 30-cm upper layer of waste foams used combined with the 60-cm lower layer of sand allowed for removal of Escherichia coli in 98.9% on average, whereas coliform bacteria - in 95.0%. ...
