Identifiering av okända avloppsströmmar - en studie i Perstorp industripark

Sammanfattning: Many water managers manage to reduce the amount of Infiltration/Inflow (I/I) that is added to the sewer system. The reason for this is to reduce the number of basement flooding and overflows. This is not the case in Perstorp industrial park. The wastewater treatment plant in the industrial park has a permit on how much water the wastewater treatment plant is allowed to release into the recipient, the I/I takes part of this condition unnecessarily. The aim of the work has been to develop a methodology for how industrial parks will work with I/I and unknown wastewater streams. The result of the work has become a draft for a methodology for identifying unknown streams of waste water and I/I in a sewage system within an industrial park. The method is developed through a literature study and from experiences and trials in the industrial park in Perstorp. The main part of the methodology is about dividing the industrial park into smaller sub-areas. The division must be done strategically in order to then be able to prioritize between the different sub-areas and perform flow measurements at suitable locations. If there are already measurements in an area, these can be used to get an idea of how much impact a precipitation event has to the area. In order to be able to divide the area, information about the area and about the sewer system is needed. The report also suggests a couple of methods on how the flow measurements can be performed and how the flow measurements can be evaluated to get answers to what type of water that is measured. Measurements and analyzes are performed in the industrial park in Perstorp. With the help of the measurements made and the impact of precipitation, about a third of the unknown flow at Perstorp industrial park has been derived. Much work remains to be able to derive all unknown flow, but a plan for continued work with the areas that need to be measured has been developed.