WaReg protects homes from flooding in Sweden

The problem

As part of routine maintenance Backaryd Water Treatment Plant backwashes their filters on a regular basis. During this process, water is discharged into the town's sewer network at a rate of 16 l/s. The town's sewer network is capable of handling a flow of no more than 5 l/s, so when it receives 16 l/s during the backwash process it becomes problematic for the downstream residents. When backwashing occurs, homes in the downstream area suffer from sewer backflows into their basements through toilets, showers, and floor drains. There are a few different methods to solve this issue. One method is to increase the pipe size to accommodate the flow. This, however, is an expensive solution for a town of 400 people. The more effective and less resource-demanding solution is to control the flow, attenuate the excess, and only release what the downstream pipes are capable of handling.