Benefits of Decentralized Wastewater Treatment (WWETT Show 2023)

Centralized Wastewater Treatment Systems, often called "big pipe" systems, collect and treat wastewater from a large geographic area with diverse inputs and generally discharge treated wastewater to a surface water.  These are the systems that most people are familiar with when they think of wastewater treatment.  Centralized systems benefited from the passage of the Clean Water Act (CWA) in 1972 and the accompanying grant funding that built, repaired, and upgraded thousands of treatment systems around the United States in the 1970’s and 1980’s. Since then communities have grown, treatment standards have increased, and the CWA funds to repair, upgrade and/or expand those WWTPs have become increasingly limited.

“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.  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, decentralized onsite wastewater treatment 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 presentation will explore the pros and cons of centralized and decentralized systems and how they can be used to complement each other in an overall wastewater strategy.

Learning Objectives:

1.  Discuss the differences between the centralized and decentralized models

2.  Identify the benefits of decentralized systems

3.  Recognize the components of a decentralized system

4.  Identify areas/situations where a decentralized system can be used for reuse

Speaker:  Dennis Hallahan, Technical Director at Infiltrator Water Technologies