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What is Decentralized Wastewater Treatment?

“Decentralized system” has become a commonly-used term to describe a wastewater treatment system that treats and disperses wastewater from individual homes or a cluster of homes at or near the source of the wastewater discharge. Decentralized systems include onsite and cluster treatment systems. Systems may serve a cluster of homes, a subdivision or small community as well as commercial and industrial complexes. If multiple sources are served by a cluster system, a collection system may be included to receive and convey the wastewater to a combined treatment and dispersal component. These systems take advantage of the vast capacity of soil to remove or transform pollutants that are in the effluent as it percolates through the soil thereby avoiding point discharges to surface waters and maintaining the quality and quantity of our groundwater.

By definition, onsite wastewater management systems are a ‘green technology’ because treated effluent recharges local aquifers. A new innovation in decentralized wastewater management is the reuse or recycling of treated effluent. With appropriate safeguards, local regulations or bylaws may allow the treated water to be used for irrigation, toilet and urinal flushing or make-up water for commercial boilers. These applications reduce the demand for potable water and aid in the protection and preservation of the available water sources.

As society demands more efficient use of financial resources and sustainable environmental wastewater management, the use of managed decentralized wastewater treatment systems is a key support structure for wastewater reuse. This requires a distributed management system supported by trained professional service and maintenance providers.

Benefits of Onsite and Decentralized Wastewater Treatment

  • Decentralized wastewater treatment systems are an effective solution to protecting water quality. They are a valuable component of watershed management plans and sustainable development programs.
  • Onsite and decentralized wastewater treatment systems can benefit both urban and rural areas by providing affordable solutions and reducing risk to the environment in unusual situations and difficult locations.
  • These systems can provide optimal water management to homes, businesses and industrial centers. Their recycling capability can support water resource management goals in many arid areas of the country.
  • Their use can support municipal wastewater treatment infrastructure by providing options for pretreatment and sewer mining and provide an alternative when centralized plants have reached or exceeded capacity.

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