Decentralized Sewer Really is a Sexy Idea Whose Time Has Come!
Carolyn Allen One of my top community concerns is water use. Hence, this blog. Irrigation is an irritant...but using drinking water (potable) for sewage transport just seems really old fashioned and wasteful to me. Yes, I'm concerned about maintenance of good controls...but with today's technology, and our growing shortage of fresh water supplies, it it beginning to get irksome that more isn't being said about "decentralized" wastewater systems.
I know, it's really not a sexy topic. But it is about one of the most precious and essential natural resources required by not only people, but every living species. So wastewater systems need to be part of your green vocabulary.
Current policy, rules and regulations in many states severely limit the potential
for using decentralized sewer to meet new and existing demands for sustainable
According to Craig Goodwin & Anish Jantrania, who wrote a paper entitled "Private Sewer Utilities - Filling the Void", its time to rethink pumping sewage miles and miles and miles.
Though decentralized sewer systems will not eliminate the need for central sewer or home onsite systems, it represents an important third choice that should be more readily available for managing the development of our communities.
Private sewer utilities once viewed as an impractical model for wastewater management are now very practical because of the technology available for managing wastewater onsite in small quantities. In 1997, U.S. EPA reported to the Congress that "Adequately managed decentralized wastewater systems are a cost-effective and long-term option for meeting public health and water quality goals, particularly in less densely populated areas." (Ref: EPA 832-R-97-001b).
Wastewater Treatment Starts with Land Use Planning
Land use planning, an important part of any social policy, is becoming challenging as society strives for balancing environmental issues with growth and economic issues. Adequate and reliable infrastructure for drinking water supply and wastewater management are a must for developing new land. The type of water and wastewater infrastructure used for land-use planning has a substantial impact on the community character.
What Is Decentralized Sewer?
Decentralized sewer systems typically have the following design elements:
1. Clustered wastewater collection, treatment and dispersal fields placed at one or more strategic locations in a development. Each cluster may support 20 residences or 500+ residences.
2. For smaller clusters, use of technology that is reasonably easy to manage and maintain.
3. For developments with 100 or more residences, treating to tertiary standards for wastewater reuse (landscape irrigation, toilet use, golf course or agricultural irrigation etc.) is now also both technically and economically feasible.
4. Though use of subsurface trenches may be possible, decentralized sewer systems often use drip or spray irrigation for dispersal of treated wastewater.
5. Operating permits and regular discharge monitoring reports provide accountability for performance. In sensitive areas, groundwater monitoring wells and regular sampling may also be required.
6. Responsible management entities (RMEs) provide the needed management infrastructure to insure performance over time. RMEs may be either publicly or privately owned and operate within a utility framework, but held accountable uniformly to applicable regulatory agencies for their performance. A utility structure, may it be public or private, best provides long-term sustainability.
Craig Goodwin is General Manager, NCS Wastewater Solutions, Puyallup, Washington
For more information regarding Decentralized Sewer Systems, www.ncswastewater.com
Anish Jantrania, PhD., P.E., is a Technical Services Engineer at the Virginia Department
of Health in the Onsite Sewage and Water Program in Richmond Virginia.
Edited by Carolyn Allen, Managing Editor of Solutions For Green