C+S August 2023 Vol. 9 Issue 8

Active Wastewater Treatment in Decentralized Applications

By Dennis F. Hallahan, P.E.

The Decentralized Active Wastewater Treatment Model Decentralized wastewater treatment involves the treatment of wastewater closer to the source, reducing the need for extensive and costly centralized sewer systems. This decentralized approach provides several advantages over traditional centralized systems. First, it offers

Decentralized systems have come of age , and they offer many benefits: • Serve over 25 percent of the US population and 30 percent of new construction • A good solution for water scarcity: extract, treat and recharge water locally, completing the water cycle in a small footprint • Can be passive resulting in minimal energy consumption and carbon footprint • Can remain operational during and after natural disasters such as floods or hurricanes The basic decentralized system consisting of a septic tank and a drainfield has performed extraordinarily well. However, in areas of environmental concern, such as estuaries, wetlands, proximity to lakes and other bodies of water, high water tables, or poor soils, decentralized systems historically struggled to provide a solution. Now, with advances in technology and design innovation, decentralized wastewater treatment systems can offer the same public health and environmental protection as centralized treatment systems. Treatment technologies that were once only available for large scale treatment systems are now available at the single-family size level. The benefits are now documented in US Environmental Protection Agency published fact sheets on decentralized systems. Further, decentralized systems, once known for only passive systems have expanded to include “Active” (Advanced) treatment options.

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AUGUST 2023

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