While we have to take the issue of nitrogen (and other nutrient) pollution seriously, we also need to examine the unintended consequences of sewering the entire coast. What impact will pumping and discharging millions of gallons of water have on the aquifer, not to mention, on CO2 levels in the atmosphere? What are some ways we as residents can reduce our nitrogen output on an individual scale?

Last week, I went to an interesting talk by USGS hydrologist Denis LeBlanc, who described the role of the Sagamore Lens in supplying the Upper Cape’s fresh water.

I’d been skeptical that pumping wastewater all over town to a centralized location for treatment, and possibly discharging it through an outfall pipe off of Nobska Point, would not impact our groundwater levels. But according to Mr. LeBlanc, even at a rate of 3-5 million gallons a day, that kind of discharge is peanuts, compared to the volume of the resource.

Whether or not an outfall pipe is a good idea is still up for debate. Experts, including Mark Rasmussen of the Coalition for Buzzards Bay, say that the strong currents at Nobska would create enough “flushing” to dilute the wastewater (treated to tertiary standards) so that it would not impact marine life or public health. But still– in a world where water is considered to be “blue gold,” is it responsible to discharge it into the ocean? Even if we can’t drink it, couldn’t we reuse it?

Eco-logical design

At a conference at WBNERR last spring, environmental designers presented some very intriguing ideas on how to turn wastewater into a resource.

These weren’t pie-in-the-sky dreamers, or con artists trying to sell you back your own pee as drinking water. These were businessmen who had built their reputation on some common-sense notions: why should you flush your toilet or water your lawn with drinking water? Why should we still be using the 2,000 year-old Roman aquaduct system to sewer our communities?

To the speakers, the saying, “the solution to pollution is dilution” is simply not the case. Instead, they suggested a closed-loop system, in which gray water is continually re-used within a building, with minimal loss.

Patrick Lucey, president of Aqua-Tex, a water management consultancy firm in British Columbia, showed slides of a LEED-certified complex he designed on a working waterfront section of Victoria.

The system is designed to reuse the gray water from sinks and showers and collect rainwater from the roof. The “wastewater” is then treated in a centralized sewage treatment that one might mistake for a luscious garden.

Wastewater from toilets is treated to a standard that could be safely used for doing laundry or watering non-edible plants, Mr. Lucey said.

The system could go several steps further by including a bio-refinery to utilize solid waste and garbage as bio-fuels for heating; co-generation technology to create electricity; and removing nitrogen and phosphorus from effluent for use as fertilizer.

Engineered ecology

Closer to home, projects at the Wrentham Mall and Gilette Stadium in Foxboro (home of the Patriots) have achieved 75-95 % water reuse by employing ecological design principles. If every large public building could do that, we’d go a long way in reducing the 1,200 gallons that Americans consume on average per day (through showers, toilets, laundry, dishwashers, and food production).

Even closer to home, a Woods Hole-based firm, Todd Ecological Design, has set the standard for using nature’s principles to deal with wastewater. In municipalities, golf courses, factories, and campuses worldwide, the EcoMachines designed by Dr. John Todd, one the founders of New Alchemy Institute, use micr0-bacteria, plants, and invertebrates to effectively digest the harmful components of wastewater. Designs often include tropical greenhouse gardens that help make this process possible, even in cold climates.

However, as Falmouth’s wastewater superintendent pointed out after meeting with Jon Todd (Dr. Todd’s son), the EcoMachine cannot get the nitrogen content low enough to meet the limits set by DEP.  In order to prevent further estuarine degradation, some parts of Falmouth need to reduce nitrogen to 3 milligrams per liter– the equivalent of 1.5 drops in a bathtub– which will likely require the services of a modern wastewater treatment plant.

You are what you eat

But there are still possibilities for concerned residents to reduce their nitrogen output. Eating less meat is one idea proposed by Dr. Eric Davidson of the Woods Hole Research Center. While this might be a startling idea to some, consider the fact that the amino acids in animal protein are made up of nitrogen, and to a large extent, are passed out of the body.

If we’re eating meat three times a day, we have a bigger nitrogen footprint. For those who don’t want to be vegetarian, thinking about portion sizes, or whether they’re eating beef, or less nitrogen-demanding pork, chicken, or fish, makes a difference.

-Eric Davidson, sr. scientist, Woods Hole Research Center

Another reason to cut down meat consumption takes a global view: in places like Brazil, rainforest is being cleared at alarming rates in order to create cattle pasture. Cutting forests reduces the earth’s ability to process CO2, and also releases extra greenhouse gases (like NO2) into the atmosphere. So, if not just for the local environment, eating meat (or chosing not to) from these places can make a big difference in terms of climate change.

What else can you do?

Finally, debate over sewering sometimes leaves out small, yet significant components of our community’s total nitrogen output: stormwater and fertilizers. If we could eliminate chemical-based fertilizers from our lawns and gardens, Falmouth could reduce nitrogen in estuaries by at least 10 %. (For info on how to reduce your lawn’s N-footprint, see the Falmouth Friendly Lawns brochure.)

And if the town could install more catch basins to deal with stormwater, less nitrogen (and other pollutants) would flow directly from the roads to sensitive ecosystems. One fun fact to remember as you’re driving in a rainstorm: that first flush of rainwater from the road brings NOx emissions from your tailpipe directly to the nearest water source.

So, a few nuances to consider as we head down the road to figuring out how to create a wastewater design to meet demands of the next century. And we didn’t even get into I/A systems, such as Nitrex or RUCK.

Special thanks to David Dow for putting his two cents in on these issues. As always, we welcome comments, questions, and perspectives.