Erillisviemäreissä

Erillisviemäreissä is a Finnish term referring to a separate sewer system. This system divides wastewater and rainwater into two distinct networks. One network, the wastewater sewer, carries only domestic sewage and industrial wastewater from buildings to a treatment plant. The other network, the stormwater sewer, collects and transports rainwater, snowmelt, and other surface runoff.

The primary advantage of separate sewer systems is improved wastewater treatment efficiency. By keeping relatively clean stormwater out of the sewage treatment process, the volume of water that needs to be treated is significantly reduced. This can lead to lower operational costs for treatment plants and a reduced risk of overloading them during heavy rainfall events, which can cause untreated sewage to be discharged into the environment.

Separate sewer systems also help to prevent the contamination of clean stormwater. Stormwater collected in its own system can often be directed to natural water bodies or used for other purposes, such as irrigation or groundwater recharge, after minimal or no treatment, depending on local regulations and the level of potential pollutants.

The implementation of separate sewer systems is common in many urban areas and is often a component of modern wastewater management strategies. While they require more extensive infrastructure due to the need for two separate pipe networks, the long-term benefits in terms of environmental protection and treatment efficiency are significant. Maintaining these systems involves regular inspections and repairs of both the wastewater and stormwater pipes to ensure their proper functioning and to prevent leaks or blockages.