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By David Venhuizen, P.E.
A few weeks back, a friend sent me an article detailing the severe problems the people in Phoenix are having with their sewer system. It is literally crumbling under their feet. There are many instances, it was reported, of long sections of pipe completely missing, with only the soil bridging to maintain a flow conduit, and sometimes that caves in, creating a "sewer sinkhole." The main culprit is hydrogen sulfide gas produced in the sewage, which oxidizes to form sulfuric acid, and that eats away the concrete sewer pipe. This, and other problems reported in the article, creates a pervasive stench in some areas of the city.
It's not that I don't like the people in Phoenix and so revel in their misfortune, but that article sorta tickled me. I sent a letter to the author, thanking him for telling his audience that "the emperor has no clothes." We are always being told that the conventional centralized sewage system is the "best" and most cost-efficient way to manage wastewater. The huge costs Phoenix is facing to replace a significant part of its far-flung collection system tell us that this is not the "slam dunk" that our mainstream wastewater management infrastructure thinks it is. Wanting to share my perverse glee at this news, I forwarded a link to the article to the EPA decentralized list, prefacing it with a tongue-in-cheek, "To paraphrase Apollo 13 commander Jim Lovell, 'Phoenix, we have a problem.' "
This is not an isolated case of large-scale centralized wastewater systems in crisis. A very active discussion occurred on two occasions on the decentralized list about severe wastewater management problems around Atlanta, sparked by articles in the Altanta Journal-Constitution . Here in Austin, we are in the midst of an extremely costly "Clean Water Initiative"—bureaucratic-speak for repairing and replacing sewers and lift stations, mandated by the EPA due to the pollution that was being caused by all the problems. We also once had a rousing discussion on the list about sewer overflows and bypasses—they routinely occur in many cities, poor Milwaukee just happened to be the city in the crosshairs that time. In fact, you could insert the name of just about any city—yes, Houston included—into that famous line of Lovell's and it would be true about their wastewater system in one way or another.
Wait a minute, you might be saying about now, what does all this have to do with Onsite Water Treatment ? Could be plenty. In my last column I set forth the proposition that "decentralized" is much broader, more all-encompassing than "onsite," that the "decentralized concept" is not just for villages and rural areas, that it can be the organizational basis for a wastewater system anywhere. Recognizing the fiscal time bomb represented by large-scale wastewater collection infrastructure, one response is to reorganize what would "normally" be centralized wastewater management systems to eliminate as much of that infrastructure as practical; that is, as decentralized concept wastewater systems.
Now the sewermaniacs are obviously not going to readily accept any such ideas, but on the expanding urban fringe where most new wastewater system development occurs, where there is not big money sunk in existing infrastructure that must be respected, a very reasonable and rational question is, why should we continually expand a system that's already blowing up on us? Why would we not instead organize more sustainable decentralized concept wastewater systems, treating and reusing the water as close to where it is generated as practical, thus eliminating a very costly infrastructure that does nothing but move pollution from place to place and that will one day represent a huge replacement cost? (And I can tell you firsthand that the costs are not limited to the sewer lines—the torn-up roads and resulting traffic delays are also very real costs.) A range of options can be considered as alternatives to just extending sewer lines ever further into the hinterlands: individual on-lot systems (perhaps under an organized management system) to cluster systems of varying scales, on up to limited versions of what may look like conventional centralized systems, as best suits the circumstances at hand.
Considering this possibility is not just some academic exercise. A major issue around Atlanta, for example, is how and where to develop new wastewater systems or to expand existing ones. Most everyone considering this matter is beholden to that Dichotomy View I wrote about last time; your choices are limited to "septic systems"—individual on-lot systems that are the sole responsibility of the property owner or user—and "wastewater systems," conventional centralized wastewater systems gathering flow from hither and yon to one large-scale treatment plant. This limited choice not only places "decentralized" in an unfavorable position—as a friend noted last week, the words "septic system" are usually preceded by "failing," his point being that this whole approach to wastewater management is seen by most as second-class and destined for ultimate failure —but it forecloses options for enhancing and expanding the "decentralized" field, and thus for enhancing and expanding the business opportunities available to those who are the audience of this magazine.
So you can see that the problems being experienced by conventional centralized wastewater systems are indeed a critical issue to the "onsite" field—the response to those problems chosen by society can create or shut down options for decentralized systems. Clearly, some education about the long-term viability of centralized vs. decentralized strategies is needed to inform those choices. At least one state "onsite" organization has explicitly recognized that the way "the sewer problem" is addressed has major fiscal implications for its members and has launched an educational effort. More such associations and other institutions affiliated with this field need to follow suit.
The content of those efforts, however, bears serious consideration.
The expanding urban fringe calls for a different message than
this field is used to delivering, rooted as it is in the traditionally
rural nature of individual on-lot systems. In this more "
intense" environment, the on-lot system must be recast
within the context of wastewater management systems, in two
very important ways. First, if on-lot systems—small-scale
cluster systems too, for that matter—are to be the permanent
wastewater management system for peri-urban communities, they
must be part of an area-wide wastewater management system
, not a bunch of independently run wastewater "disposal"
systems. Second, on-lot systems need to be integrated as just
one tool in the toolkit that includes the whole range of organizational
options, using the one that makes the most fiscal and practical
sense in each situation.
But oh that word "practical." The sewermaniacs would doubtless say such an integrated wastewater management system is not "practical" because management entities are not organized to run a variety of system types and scales, and besides, you couldn't afford to properly manage dispersed small-scale facilities anyway. Such problems are, of course, just the artifact of how things have historically been done.
Sure, it would be difficult to manage a decentralized concept
system that is made up of a mix of system types if you
don't organize your management system around that task .
You can manage anything—it's simply a matter of breaking
down the functions to be managed and then building up the
institutions to address those functions. Saying a decentralized
concept system cannot ever be managed because existing
institutions aren't set up to do that is a pretty ridiculous
argument. If society understands that a decentralized concept
approach to wastewater management will be to its fiscal advantage,
then society will organize management systems that
can deal with that.
As for the affordability of managing a decentralized concept system, that is largely a matter of using technologies well suited to dispersed deployment and able to operate consistently and reliably with a minimum of active oversight. That will require that this field critically re-examine its product line, but that's another subject for another time.
None of this will be easy, of course. Institutional inertia will retard such changes and vested interests in the status quo will fight them. But the problems with conventional centralized wastewater systems are manifest and are growing. Phoenix, Atlanta, Austin, Milwaukee, Houston . they all have a problem. Going decentralized does not solve it all, but it certainly can stem its growth and prevent the same problems in the areas we are developing now from being presented to the next generation. We need to transcend our "onsite" focus and communicate that to society.
DAVID VENHUIZEN, P.E., is based in Austin, TX. Comments,
suggestions, and your own anecdotes about this field can be
sent to him at waterguy@venhuizen-ww.com
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- September/October 2005
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