The study concerns the sewage system of Kranj, Šenčur and Naklo communities which gravitates to the central sewage treatment plant of Kranj, and is managed by the Slovene public company “Komunala Kranj d.o.o.”. Adapted technical solutions were set forth for the improvement of stormwater management (drainage, discharge and/or storage) from public roads and public surfaces (ex. parkings) taking into account the current state of the sewage networks and available facilities.
In a first phase, the design and operating conditions of the current sewage networks were assessed based on recorded cadastral data, our own scouring of the terrains and sewer smoke testing. We found that the current management of the stormwater from public roads and public surfaces is generally inadequate because often too polluted water is directly evacuated into the environment. In a second phase, updated various data sources on the size of communities, water consumption from all origins, drainage conditions of stormwater, the slope of the terrains, and road load by vehicles traffic, were collected and were the basis for this study.
For the Zlato Polje area of Kranj, we have shown that by inserting new sewage section heading to the local Sava river for the evacuation and purification of critical stormwater through a gravity oil separator, we can reduce both overall burdening of the sewage system and the impact on the environment by the stormwater.
Also, we have suggested for the large-sized communities the construction of new faecal wastewater sewage sections conveying directly to the waste treatment plant in order to bypass the current mixed system. Following the German standard ATV-A 128E, dimensioning of stormwater overflows and stormwater retention tanks were carried out including the design of the required various wastewater management elements.
Finally, the regulating equipment necessary for the proper wastewater management of the above mentioned localities, especially for the Kranj area, was recommended.