Outside The Pipe: Onsite Treatment In Municipal Systems

No law says all municipal wastewater must be treated in a central plant and discharged to a stream. When might land-based treatment be practical?

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I used to edit Onsite Installer magazine, written for contractors who install onsite wastewater treatment systems (for simplicity’s sake, septic systems).

During those years I learned that the onsite and “big pipe” communities were to some extent sworn enemies. Onsite contractors and septic system owners felt threatened by ever-expanding sewer systems. Municipal treatment agencies looked down on septic systems as temporary, questionably effective and failure-prone.

However, I’ve learned from that experience and my tenure as TPO editor that both types of treatment have their place — each should welcome the other as part of a big-picture solution for managing wastewater. And that means onsite, soil-based treatment may in some cases have a role to play in serving municipalities.

Where can it work?

You might ask: how and where? Well, for one thing, in these times of (in my view, penny-wise-and-pound-foolish) austerity, municipal clean-water agencies struggle to maintain the pipes they have, let alone expand to serve new developments. What if, instead of building pipes out to a subdivision on the far fringe of town, a municipal agency contracted with an onsite specialist to build a system in which homes discharged to septic tanks, in turn discharging to low-pressure sewers, which ultimately emptied into a large drainfield?

Or, suppose a lagoon system, facing stricter limits on nutrients, can no longer meet permit limits for discharge to a stream. One solution might be to spend the money to build a mechanical treatment plant. Another might be to use soil-based treatment. A profile of the Fairfield Glade Community Club treatment system in this issue describes how this private entity’s large lagoon system discharges to spray irrigation and drip dispersal systems.

Does this mean a wastewater utility would lose control over areas served by soil-based treatment? Not at all. Those entities are just as capable of managing cluster or drip systems as they are of running central treatment plants.

Can small be better?

Still, for municipal agencies, soil-based solutions remain rare exceptions to the “big pipe” rule. Somewhere along the line, it became dogma that sewers versus septics was an either-or proposition, and from the municipal viewpoint, sewers were always better than any alternative. Maybe that was an artifact from years of bad experiences with open latrines and outhouses. Maybe it was from seeing the impacts of septic systems poorly maintained or built where they didn’t belong.

But now, the cost of the “big pipe” can be daunting in some settings. Meanwhile, scientists and regulatory officials have figured out which types of soils can support septic systems and which cannot. And inventors have figured out how to take the physical and biological processes that work in municipal treatment plants and translate them to small systems that can cost-effectively serve individual homes and small cluster communities.

One and the same? 

At conventions of onsite treatment specialists, I used to hear talks about watershed approaches to wastewater treatment, how sewers and septics were different parts of the same whole and how septics in the context of municipal service were perfectly appropriate environmentally and more attractive economically.

Now that I’m on the “big pipe” side, I don’t hear that anymore. Or at least I didn’t until I learned about the Fairfield Glade installation in Tennessee. (Granted, Fairfield Glade is a private development, but it is definitely municipal in scale.)

One positive sign: A few years ago the National Onsite Wastewater Recycling Association (NOWRA), trade association for onsite professionals, formed a relationship with the Water Environment Federation (WEF), based on a mutual understanding that decentralized wastewater treatment is an important part of the national treatment infrastructure. The two have worked together on various initiatives, and NOWRA is well represented on the WEF Small Communities Committee.

Eric Casey, NOWRA’s executive director, observes, “We need only look at the exponential growth in capital expenditures most utilities are facing to repair and maintain aging infrastructure to realize that their current business model is increasingly unworkable.

“More thought leaders from the centralized sewer community are recognizing that decentralized wastewater treatment has to become part of their business model, not just because it is less expensive, but also because it is a more sustainable and resilient technology. What’s more, distributed infrastructure can be done profitably.” 

What’s your view?

Here’s my chance to ask the “big pipe” community: Do you see a role for onsite, soil-based solutions in municipal collection and treatment schemes? I would be greatly interested in your perspectives. Send your thoughts in an email to editor@tpomag.com. I promise to respond, and we’ll publish a sampling of comments in a future issue.  



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