erillisviemäreiksi

Erillisviemärijärjestelmä, often referred to as separate sewers, is a wastewater management system where sewage and stormwater are collected and transported through distinct, independent pipe networks. This contrasts with combined sewer systems, which carry both types of wastewater in a single pipe.

In a separate sewer system, one set of pipes is dedicated to carrying domestic and industrial wastewater (sewage) to a treatment plant. Another separate set of pipes is designed to collect and convey rainwater runoff (stormwater) from streets, roofs, and other surfaces. Stormwater may be discharged directly into local water bodies or undergo some level of treatment depending on regulations and environmental concerns.

The primary advantage of separate sewers is improved wastewater treatment efficiency. By keeping stormwater out of the sewage system, the volume of water reaching treatment plants is significantly reduced. This prevents the overloading of treatment facilities during heavy rainfall, which can lead to untreated sewage being discharged into rivers and lakes in combined systems. Consequently, separate systems generally result in cleaner effluent discharged from treatment plants.

However, implementing and maintaining separate sewer systems can be more complex and costly. It requires the construction and upkeep of two separate underground networks, which can occupy more space and involve higher initial investment. Nevertheless, the long-term environmental benefits and improved water quality often outweigh these initial challenges. Many municipalities are transitioning from combined to separate systems or upgrading their existing separate systems to enhance their performance and reduce environmental impact.