Erillisviemäröintijärjestelmät

Erillisviemäröintijärjestelmät, or separate sewer systems, are wastewater management strategies that divide the flow of water into distinct networks. Typically, these systems consist of at least two separate pipe networks. One network is dedicated to collecting and transporting stormwater runoff from streets, roofs, and other impervious surfaces. The other network is designed to carry domestic and industrial wastewater, also known as sewage, from buildings to a treatment facility.

In contrast to combined sewer systems, which carry both stormwater and sewage in a single pipe, separate sewer systems offer several advantages. By isolating stormwater, the volume of water reaching wastewater treatment plants is significantly reduced, especially during rainfall events. This can lead to lower operational costs for treatment plants and prevent them from being overwhelmed, which could otherwise result in untreated sewage being discharged into waterways.

Furthermore, separate sewer systems help to minimize the risk of combined sewer overflows (CSOs), where excessive rainfall can cause the combined sewage and stormwater to exceed the capacity of the system and overflow directly into rivers, lakes, or oceans. The separation of flows also allows for more targeted treatment of pollutants, as stormwater may contain different contaminants than domestic sewage. While the initial construction cost of separate systems can be higher due to the need for multiple pipe networks, the long-term benefits in terms of environmental protection and operational efficiency are often considered substantial.