Green Pond, Bournes Pond, and Eel Pond in East Falmouth

A week after a day-long symposium on the potential for outfall pipes to handle the Cape’s wastewater problem, I’ve finally figured out what’s been bothering me.

It seems that wastewater managers and engineers, in their infinite wisdom, operate according to the “if it can be complicated, why make it simple?” ethic.

The speakers at the ocean outfall forum did not mince words: it would take no less than an amendment to three state acts protecting marine resources—not to mention, years of study and millions of dollars— for an outfall pipe to be constructed on these shores.

They were less candid about the probable impacts on the environment— and were subtle about the whole reason for entertaining the idea of an ocean outfall: it’s cheaper than the only other “approved” method of disposing of wastewater.

Having attended my fair share of conferences, symposia, summits, and forums on wastewater, it seems that there are two distinct schools of thought on the issue. Some play by the rules, insisting there is no way to serve an entire municipality with anything other than sewers and wastewater treatment plants. Others push for “alternatives” such as composting toilets and shellfish aquaculture— options that seem outside the box until you realize that’s the way humans have been disposing of their “waste” for millenia.

An important difference between these two schools of thought is the attention and resources given to the “big pipe” option, while grassroots groups are left to their own devices to promote eco-toilets or aquaculture. Kudos to the Falmouth wastewater committee (CWMP-RC for short!) for opening their minds and supporting a successful town meeting article to give sewering alternatives adequate study— while the taxpayer-funded report by the engineering firm Stearns & Wheler did not.

Known unknowns

An ocean outfall off of New Jersey (courtesy World News Network)

Popular in places where sanitation services are lacking, outfall pipes have fallen out of favor around the globe. Speaking on “possible environmental impacts,” Batelle scientist Carlton Hunt pointed out that the effects of putting semi-treated wastewater into our precious ocean are pretty much unknown.

Think about what products you use in the shower, the kitchen, the laundry room. Would you want to swim in it or eat it later on the half shell? What about road runoff that flows into storm drains?

Dr. Hunt also pointed out the anti-microbial nanotechnology that is appearing in everything from hand sanitizers to socks. David Dow, of the Cape & Islands Sierra Club chapter, pointed out that the byproducts of pharmaceuticals and personal care products are known to cause reproductive problems in fresh-water fish and amphibians. Studies have shown these contaminants of emerging concern in most of the country’s drinking water supply. What will they do in the ocean? We simply don’t know.

We also don’t really know what pumping precious drinking water into our toilets and sinks, and back across town for treatment will do to the water table— or to our municipal energy bills. We may not be water-poor on Cape Cod, but as the Dr. Hunt pointed out, we don’t know what to expect with climate change. Is it wise to build energy-intensive infrastructure in this age of sea level rise and uncertain weather patterns? How many more wind turbines will we need to handle the additional energy demand? (and how will nearby residents feel about that?!)

A truly holistic approach

Nate Weeks of Stearns & Wheler-GHD, with Dale Saad of the Barnstable DPW and Paul Niedzwiecki of the Cape Cod Commission.

There are essentially two reasons for considering an ocean outfall: the wastewater need not be treated to a point where it’s basically drinkable (through reverse osmosis)and town-owned land resources for groundwater discharge are dwindling.  Finding a suitable discharge site is complicated by the need to avoid putting nutrients back into the ground, which would require sewering the discharge area.

All these problems add up to one thing: groundwater discharge will be expensive.

One of the main messages from the panelists is that we need a “holistic approach” to solving our wastewater problem.

For hydrologists, that means recharging the treated wastewater into the groundwater or for irrigation. For Paul Niedzwiecki, director of the Cape Cod Commission, “holistic” means we need to collaborate as a region, rather than as individual towns. For Nate Weeks, of Stearns & Wheler-GHD, the term means we need to consider all the big-pipe options, no matter the regulatory obstacle course. For residents advocating for eco-toilets, aquaculture, and inlet widening, the answer lies in using our unused nutrients as compost and fish food, removing the “waste” from the wastewater equation.

It could be that being truly holistic means trying all these approaches, but in the end, decisions will have to be made. Why not make it simple, if we can avoid the complications?

Are we flushing money down the toilet?

As someone who goes to a fair share of wastewater-related meetings, I wasn’t expecting to be blown away at last weekend’s Eco-Toilet Summit.

On a conceptual level, I felt I already understood the basics of composting human waste— hey, I do it every day with food scraps.

Adding one step through my digestive system to my garden seemed to make sense… from a theoretical point of view.

But after hearing about the range of eco-toilet options available, and a variety of perspectives from regular residents, the theoretical became possible.

What stopped making sense is the way we use—and view—the bathroom.

Saturday’s Eco-Toilet Summit was a one-stop shop for those interested in reducing household water use and recovering nutrients from our excretia to make fertilizer to grow food.

A mid-size Phoenix composting toilet

Curious residents flocked to the shrines of ecological design—a large blue Phoenix composting toilet, the Ecovita’s familiar white bowl with a tiny hole for urine diversion, and the diminutive, portable Pacto toilet—and took advantage of the friendly sales representatives to ask questions:

How do they work? Does it smell? How much would it cost to install?

Sponsored by a coalition of grassroots environmental groups, the afternoon was dedicated to learning more about modern ecological approaches to dealing with an age-old problem: how and where to dispose of our waste?

That is the $600 million question, as Falmouth considers ways to clean up decades of nitrogen loading to sensitive coastal embayments, and one which the summit’s sponsors hope can be answered with alternatives to centralized sewering.

I know. Maybe not everyone’s cup of tea. But for anyone who poops and pees, it might be worth it to hold your nose and pay attention.

Eco-logical justice

The go-to solution for the past several decades has been centralized sewering, which collects sewage, storm water, and graywater (laundry, shower, and dish water) in a network of underground pipes for treatment and eventual release back into the groundwater.

I won’t get into all the pro’s and con’s of sewering here, suffice to say that there are two factions of environmentalists doing battle in town: biologists who favor sewers as a proven way to keep nutrients out of the groundwater; and ecologists who view the cycle of nutrients as a “closed-loop” system and favor composting to pump n’ treat.

It’s a fascinating chapter in environmental history, as we discover how we are all responsible for the decline of eel grass and shellfish in our beloved harbors.

The debate also takes on an environmental justice perspective, as one considers the economic cost-benefits of sewering vs. composting or diverting our waste.

Eco-toilet panelists Abe Noe (Phoenix), Carol Steinfeld (Ecovita), Hilde Maingay (the Green Center) and former state rep Matt Patrick

For eco-toilet advocates, the solution to nutrient management lies in closing the loop between waste and resources.

With urine-diverting and composting toilets, the waste products are collected and pumped out roughly every six months, depending on the size of the household. With a compacting toilet, waste is packaged neatly into a plastic or biodegradable bag, which can be collected for compost or thrown out weekly with the garbage, just like regular diapers.

Storage from six months (for urine) to two years (for solids) removes pathogens from the waste, a process that may also break down pharmaceuticals and contaminants of concern.

A composting toilet or urine-diverting system takes advantage of biological processes to break down the nutrients in urine and feces to create potent fertilizer and carbon-rich humus, said Don Mills, a sales manager for the Lawrence-based compost toilet vendor Clivus Multrum.

A conventional wastewater treatment system uses the same process, but combines household waste with stormwater, requiring enormous amounts of energy to pump and adding heavy metals and pollutants to the mix.

Earle Barnhart, whose Green Center organization was the primary sponsor of the summit, noted that treating human waste as a resource could lead to the development of new industries. Whether collected and processed on-site or elsewhere, the compost and fertilizer could be sold and used to grow organic produce, he said.

Dollars and sense

For former state representative Matt  Patrick, the eco-toilet alternative would save residents millions in betterments and taxes to finance the sewer system. Going the sewer route, he warned, could force middle- and low-income residents to leave town.

I don’t think any of us want to live in a community that’s all wealthy, where middle class and low-income families can’t afford to live. But that might be one of the outcomes if we press forward with a conventional sewer system.

-Matt Patrick

According to Mr. Patrick, installing two urine diverting toilets in every home in the south coast watershed would amount to just 10% of the cost of sewering those neighborhoods.

(2 UD toilets + 2 UD urinals @ $1,500-$3,000/home)                    x 8,000 homes = $12-24 million

+ $175/year pump-out  x 8,000 homes = $1.4 million

x 10 years= $14 million

Grand total cost for 10 years installation & maintenance:

$26-38 million.

Not only would about 80 percent of the nitrogen currently leaching from septics be stopped in its tracks, but local plumbers and waste service industries would be employed by this system, Mr. Patrick said.

The cost for each alternative system varies depending on household needs, but the vendors estimated about $1,000 for a micro-flush urine-diverting toilet; about $1,100 for a compacting toilet, plus $200 a year for disposable bags; and up to $6,000 for a large composting toilet, not including installation and maintenance.

A three- to 12-watt fan is required to remove odors from the composting system, but Mr. Patrick noted that the electricity cost for such a system is less than one energy-saving light bulb.

The Falmouth precedent

One of the recurring questions from the audience was whether this innovative method of handling waste had been done elsewhere.

Mr. Patrick said that UD toilets are popular in Sweden. Don Mills of Clivus Multrum pointed out that Europeans, Americans, and Asians only stopped using “night soil” as fertilizer in the last century.

I might add that Africans are also composting their waste, providing low-cost sanitation as well as bananas, a source of food and income.

Hilde Maingay, of The Green Center, makes the case for eco-toilets as a means of achieving social justice

Faced with an almost overwhelming dilemma, Falmouth has a unique opportunity to set a precedent among coastal communities. Yes, it is scary to be the guinea pig—but how appropriate, given our world-renowned science community and ecological pioneer residents.

Money is relative to social justice and long-term stability. [Eco-toilets] could add more stability to communities and make them more socially just.

-Hilde Maingay, the Green Center

The Eco-Toilet Summit organizers are not expecting anyone to just take their word for it, however.

They are hoping for a study of these alternative systems, including an energy-use cost-comparison with a conventional system and the regulatory mechanism by which residents could install (and maybe even get loans for) an eco-toilet system of their choice.

The cost-benefit

Mr. Patrick is in favor of urine-diverting toilets, which sequester the high nitrogen content in urine while using small amounts of water to flush feces into a septic system.

He’s a fan because of the relatively low cost and high nutrient recovery. Given that the system only needs to be pumped periodically, the maintenance requirements are also pretty low.

Composting toilets are already approved by the Department of Environmental Protection and are widely used in Massachusetts, but urine-diverting toilets have yet to go through the permitting process.

While the jury is still out as to whether composting waste will remove the pharmaceuticals and other harmful chemicals, eco-toilet proponents make a good point that it is better to remove those “contaminants of concern” from the waste stream altogether, rather than combine them for centralized treatment.

Currently, most wastewater treatment plants lack the technology to remove the aspirin, caffeine, hormones, and pesticides from effluent anyway.

Even with an eco-toilet, septic systems would still be required to handle the household laundry, bathing, and dishwater, also known as graywater. The pollutants associated with those systems would not be addressed by an alternative toilet system either.

I’ve written at length about UD toilets, composting and compacting systems elsewhere on Under the Lens, so please click here if you are interested in the details.

Footnote: it’s in the report

For further reading, it’s interesting to note that Stearns & Wheler, the engineering design firm that developed a draft of Falmouth’s comprehensive wastewater management system, devoted a few pages to “waterless toilets” and UD systems in its 454-page report.

a. Wastewater flows and loads are reduced if properly designed and installed.

b. Water consumption is significantly reduced.

c. Minimal environmental concerns occur when properly sited and designed.

d. Composting toilets require minimal energy use.

e. Size of standard septic system can be reduced to treat only gray wastewater.

f. Routine maintenance is minimal and requires no special training.

As for urine diverting toilets, Stearns & Wheler lists the advantages:

a. Water consumption is reduced.
b. Minimal environmental concerns occur when properly sited and designed.
c. The nutrients in the urine could be positively recirculated in the environment by use as fertilizers.
d. The technology could decrease the nutrient removal costs associated with wastewater (less the urine component) at the WWTF.

Urine source separation toilets have the following disadvantages, according to Stearns & Wheler.

a. Existing biological and chemical technologies at WWTFs are not sufficient to treat concentrated urine. Additional facilities would need to be designed and constructed.
b. Homeowner renovation costs would include new toilets, plumbing, and urine storage facilities. Urine separating toilets are likely to be costly and lack decorative design options which may decrease homeowner acceptance.
c. Increased homeowner disposal hauling costs associated with two separate collection systems.
d. Septage hauling trucks may need retrofitted equipment to properly handle concentrated urine.
e. Technology works correctly with proper use. Proper use is limited to sitting on the toilet, meaning behavior modification for males.
f. Technology works correctly with proper maintenance, which includes removing urine scale that can block pipes over time and using certain cleaning agents which would not contaminate the collection tank.
g. Human urine use as an agricultural fertilizer may not be socially acceptable.
h. Not well suited to high seasonal community and tourist population.

A typical urine-diverting toilet collects solid and liquid waste, which could be processed into fertilizer, removing nitrogen from the waste stream

Considering that we all flush at least three times a day, it’s surprising how little we know about where our waste goes. Into a white bowl and then down a pipe— never to be seen, smelled, or thought of again.

But as many Cape Codders are beginning to realize, that’s not really the case. The by-products of our waste are seeping out of underground septic systems and into the groundwater, flowing finally into coastal ponds. The nutrients are harmless by themselves, but in concentrated form, throw off the ecological balance of sensitive estuarine systems.

Though there are many nutrients and “contaminants of concern” to be worried about, nitrogen is known as the culprit for changing pristine harbors into algae-filled swamps, devoid of marine life. Or so we fear.

Last night, Falmouth selectmen approved a town-wide comprehensive wastewater management plan (CWMP), developed over the course of several months last year by a panel of community members. It calls for over $300 million to install a sewer system in the neighborhoods south of Route 28 from Little Pond to Seapit Peninsula. Millions more are expected to sewer the next phases north of Route 28.

The CWMP committee and selectmen also set aside funding for the study of alternatives to sewering, which could lower the overall cost of the plan.

Several of these options were covered in a forum held earlier this month at the Waquoit Bay National Estuarine Research Reserve (WBNERR), in which four experts in various areas of wastewater treatment delivered “The Scoop on the Poop” from the perspective of traditional sewer systems, alternative systems, shellfish aquaculture, and coastal engineering.

It’s not as complicated as it sounds. In fact, it should be taught in grade schools.

The big pipe method

Falmouth's wastewater treatment plant on Blacksmith Shop Road is one of just five such facilities on Cape Cod

Michael Giggey, the senior vice president of Wright-Pierce, an engineering and consulting firm, started off the evening with an overview of the municipal treatment options, from individual “on-site” systems to cluster and satellite systems to centralized wastewater treatment facilities.

As an advisor to the Town of Orleans on its comprehensive wastewater management plan and an islandwide wastewater plan on Martha’s Vineyard, Mr. Giggey noted that each watershed has different needs, which can be met through a combination of technologies.

The simplest option, he pointed out, is to simply eliminate the main controllable source of nitrogen pollution by removing enough septic tanks to meet the TMDL and connecting those homes to a sewer system, discharging the treated effluent outside the watershed.

However, across the Cape, that strategy has proven to not be so simple, and certainly is not cheap.

In Falmouth alone, the cost of sewering homes south of Route 28 from Little Pond to Seapit Peninsula is expected to cost $310 million for the first two phases, to be paid for by a combination of taxes and homeowner betterments. Across the Cape and Islands, these figures add up to billions.

In a report compiled last April by the Barnstable County Wastewater Cost Task Force, the study found the most important factor when choosing a wastewater treatment strategy is the amount of nitrogen that each system can remove per dollar spent. Centralized wastewater treatment facilities can reduce nitrogen down to 3 milligrams per liter, whereas effluent from on-site denitrifying systems ranges from 10 to 19 mg/L, Mr. Giggey said.

Though sewer mains and wastewater treatment facilities require a large amount of capital up front, the task force found that operation and maintenance costs for a centralized sewer system were far lower than on-site denitrifying systems, cluster, or satellite systems.

“It’s not just about cost, but cost-effectiveness,” said Mr. Giggey, who served on the task force. “It would seem the most cost-effective option is with the larger systems.”

David Dow, president of the Cape and Islands chapter of the Sierra Club, asked Mr. Giggey whether wastewater managers on Cape Cod have had any experience with removing “contaminants of concern” from effluent. These chemicals are the byproducts of pharmaceuticals, personal care products, and detergents that most wastewater systems do not treat, or even monitor.

“Unfortunately, there’s not a lot of local experience. We’re just now getting our arms around what nitrogen does. Contaminants of concern are not just one compound, it’s thousands,” Mr. Giggey said.

Innovative & Alternative systems

The British-designed "Loowatt" toilet was originally built with the waste disposal needs of developing countries in mind.

Also serving on the task force was panelist George Heufelder, director of the Barnstable County Department of Health and the Environment, who established the Massachusetts Alternative Septic System Test Center at the Massachusetts Military Reservation in 1999.

Mr. Heufelder noted that every wastewater treatment option works on basically the same principle: to “manipulate the nitrogen cycle inside a black box.” Though some methods are more efficient than others, the basic idea is to break down nitrates into nitrogen gas, a major component of the air we breathe.

In over a decade of testing, Mr. Heufelder found that innovative and alternative (I/A) systems “remove about 50 percent of the nitrogen 70 percent of the time.”

Emerging membrane technologies, such as the Nitrex, is capable of removing 90 percent of nitrogen from groundwater. The Nitrex, which Mr. Heufelder referred to as “a box of proprietary cellulose material, otherwise known as wood chips,” and other membrane systems are also becoming cheaper and easier to maintain.

A composting toilet: the only difference is the pipe

Another affordable and effective option for individual homeowners is the composting toilet, which Mr. Heufelder noted has an added benefit of separating toilet waste from graywater—the shower, sink, and dishwasher water that usually goes down the drain.

In an earlier comment from North Falmouth resident Alison Robb about the need to keep drinking water from becoming wastewater, Mr. Heufeulder agreed that the tradition of defecating into potable water “is lunacy, but we do it.”

However, he said it would probably require “mass hypnosis” to get every resident to install a composting toilet and never put kitchen scraps or chemicals down the drain. Even if Town Meeting members bought into composting toilets as a nitrogen management strategy, the Department of Environmental Protection would need a way to ensure its regulations were being met, he said.

“It’s trust and verify. Not everyone’s composting nicely in the back yard. There will be some nitrogen [in the system], and we need to know what it is,” said Mr. Heufelder.

The Eco-flush urine diverting toilet can remove 90% of the nitrogen from human waste, using 80% less water than a traditional toilet

Another innovative home nitrogen removal method on the market is the urine-diverting toilet, which was on display at WBNERR, thanks to Conrad Geyser, president of Cotuit Solar.

Though Mr. Heufelder admitted that he and other men might have a problem sitting down to use the toilet, he said one day the market for phosphorus and nitrogen would put a premium on mankind’s most abundant waste product.

Because urine contains up to 90 percent of the nitrogen and 50 percent of the phosphorus in domestic wastewater, separating and collecting it is also a simple way to prevent nutrients from reaching the groundwater.

“I envision a day when someone comes to your door to write you a check for good-quality urine,” Mr. Heufelder said, estimating that there is a total of 150 more years of phosphorus left in traditional mines.

Mr. Heufelder noted that membrane systems can be “a little power hungry,” using five to eight kilowatt hours per day in a typical home. However, the Nitrex makes use of a trickling system with lower energy use, he said.

There are other costs associated with on-site systems that should be factored into their overall costs, said Mr. Heufelder, estimating that one full-time employee would be required for every 1,500 on-site systems to ensure they meet environmental standards.

Furthermore, homeowners are required by regulations to have a maintenance contract for their on-site system, and any residual waste would have to be disposed or converted into fertilizer by a private company, he said.

“I cannot imagine DEP allowing composting or urine-diverting toilets unless the residuals leave the watershed completely,” he said.

The shellfish solution

The Sippewissett oyster, a product of local aquaculture efforts

While town officials and residents tend to focus on technical solutions for wastewater treatment, local scientists are turning to Mother Nature to help reduce the nitrogen load.

Diane Murphy, an aquaculture and fisheries specialist for the WHOI Sea Grant and Cape Cod Cooperative Extension, gave an overview of the potential for shellfish aquaculture to remove nitrogen from sensitive coastal embayments.

While shellfish are becoming more accepted as a method for meeting total maximum nitrogen loads (TMDLs), Ms. Murphy emphasized that aquaculture should not be considered the only solution for reducing nitrogen loads.

“Oysters can serve a crucial role in the uptake of nitrogen. Aquaculture should not be the sole source, but should be integrated into a nitrogen management plan,” she said.

Acting as grazers on the sea floor, oysters and other shellfish consume the phytoplankton that tend to grow in the presence of elevated nitrogen levels. The more food there is, the more the oysters grow.

Though there are conflicting reports on how much water oysters are capable of filtering each day, the accepted number is about 20 gallons per day, Ms. Murphy said. Studies have found that a market-size oyster can sequester an average of 0.52 grams of nitrogen and 0.16 grams of phosphorus over its lifetime.

When harvested, all that nitrogen is removed from the ecosystem “free of charge,” she said.

Based on a study of the 2006 oyster harvest in Wellfleet, Ms. Murphy said that 20,000 bushels of oysters can assimilate 282 kilograms of nitrogen. The oyster feces become buried in the sediment, stimulating denitrifying bacteria, a process that results in nitrogen gas being released to the atmosphere. In Wellfleet that year the total nitrogen removed was 2.3 tons.

Even though oysters are good to eat, Ms. Murphy does not advocate turning every coastal pond into an aquaculture site, noting the impact on recreational users’ access to and enjoyment of the water.

A large-scale oyster aquaculture project could clean up Falmouth's coastal ponds, create jobs and increase local food production

About 2.5 million oysters would be needed to filter all the water in Waquoit Bay, Ms. Murphy said, requiring about 10,000 square meters, or about 2.5 acres, for all of the gear.

According to an estimate by Woods Hole resident and aquaculture consultant Ron Zweig, many more oysters may be necessary to adequately filter the water, covering up to 30 acres of the 825-acre bay.

The ecosystem also has a certain “carrying capacity” for aquaculture production, and even oysters have their limits before disease, predation, and lack of food inhibit their growth, she said. Because each estuary is different, she recommended a feasibility study to determine how extensive an aquaculture operation the ecosystem is capable of supporting.

Mashpee Shellfish Constable Rick York. said that conditions in the estuary also determine the type of shellfish most suitable for aquaculture. In the low salinity of the Mashpee River, he had great success in growing half a million oysters without fear of predation or disease. Since 2005, the oysters have removed over a ton of nitrogen, he said, which increased the dissolved oxygen content to the point of being safe again for fish.

However, he said the Mashpee River is unique, and in other areas he would recommend seeding quahogs instead of oysters.

“I take issue with oysters having the most potential,” he said. “Quahogs don’t filter as much water, but they consume as much nutrient.”

Flushing the bays

Another strategy to decrease the impacts of nitrogen in sensitive embayments is to increase the amount of “flushing,” or exchange, between the ocean and the estuary.

Nitrogen concentration is higher at the head of coastal ponds, but becomes diluted in areas of greater flushing

The adage, “the solution to pollution is dilution” rings true in this case, said John Ramsey, a senior coastal engineer at Applied Coastal Research and Engineering, a Mashpee firm.

If the tidal conditions are right, nitrogen concentrations can be decreased to acceptable levels, even if the load remains high, he said. Since people tend to live near the water, the nitrogen load at the head of the bay tends to be higher than that near the tidewater.

Due to coastal geology, estuary inlets tend to become filled with sand, or even become blocked by the formation of barrier beaches, he said, showing slides of such events. Unless the inlets are dredged, flushing will decrease over time, Mr. Ramsey said.

Even if the inlets are maintained, all tides are not created equal. While Cape Cod Bay has a 13-foot tide, Vineyard Sound only has a 1.5-foot fluctuation, and Buzzards Bay tides are about 4.5 feet.

“The size of the pump matters,” Mr. Ramsey said. Some towns, he said, “are at a huge disadvantage for tidal flushing.”

Green Pond, Bournes Pond, and Eel Pond in East Falmouth

In Falmouth, Bournes Pond has been cited as one area that does get a generous amount of flushing activity. Mr. Ramsey said if the inlet could be widened from 50 to 100 feet, the coastal pond’s nitrogen concentration would be reduced from 0.6 milligrams per liter to 0.46 mg/L. That reduction would mean that half as many homes in the Bournes Pond watershed would have to be connected to a sewer, he said.

Although on paper widening the inlet seems like a win-win solution, wetland protection regulations place restrictions on projects of this kind because of the impacts on barrier beaches, which protect coastal zones from storms and flooding and provide habitat for endangered species, said Mr. Ramsey.

“Widening the Bournes Pond inlet will create a bigger footprint of impact on the barrier beach system. It’s something regulators will struggle with,” he said.

Given that its now easier to find oysters from Duxbury and mussels from Prince Edward Island than it is to get locally-sourced seafood, this locovore’s dilemma begs the question: which came first? The shellfish or the septic system? The problem or the solution?

Sometimes, when overhearing discussions among wastewater experts, the idea is floated that Cape Cod should try to get back to 1619– that is, before Pilgrims landed on these shores.

Though it took until roughly 1990 for humans to load the estuaries with enough nitrogen to kill small fish, the basis for the idea is that we should limit our inputs to the environment to basically zero, just as the native Wampanoag did.

Here's what eel grass should look like

In the past three decades, we have developed our communities to the point where the nitrogen leaching from household septic systems and fertilized lawns has caused our beloved estuaries to seriously decline.

Across the entire Cape, algal blooms clog and stink up the water, leading to unpleasant swimming and boating experiences– and signaling a major ecological disaster.

A lack of eel grass is often the first sign that nitrogen loading has tipped the scales towards an unhealthy estuary. As nitrogen seeps in with the groundwater, it causes algae to grow– and infamously, bloom, when summer temperatures heat up.

Not only is it yucky to look at, algae blocks the sunlight needed by eel grass, causing a rapid decline for this aquatic plant species– as well as the shellfish that grow on its blade and stems.

Dying eel grass: a familiar sight in Falmouth harbors

As the algae dies off, it sucks up the oxygen in the water. If the die-off is extensive, it can cause dissolved oxygen levels to get so low that fish die– or swim to less suffocating areas.

The less lucky marine creatures– snails, worms, and shellfish– are not mobile, and tend to die at much greater rates than fish.

So how do we get back to the way it was in 1619? The state, through the Massachusetts Estuary Project, has set daily maximum nitrogen loading (TMDL) targets that we’ll need to achieve to restore the estuaries, but does not offer any guidance on how to get there.

We need only take a lesson from nature to understand how the nitrogen cycle has balanced itself out over millennia.

A bi-valve solution

While towns on Cape Cod brace themselves for a lengthy, costly, and energy-intensive installation of a sewer system, some residents have taken a back-to-the-Earth approach.

Drawing on his 30 years as an aquaculture consultant with the World Bank, Woods Hole resident Ron Zweig thinks that the solution to the Cape’s water woes could be staring at us from our dinner plates.

Mr. Zweig’s experience with aquaculture in Southeast Asia and at the New Alchemy Institute in Hatchville corroborate the findings of numerous studies establishing the ability of shellfish to filter and remove nutrients (mainly nitrogen and phosphorus) from water and suspended sediments.

A Falmouth Shellfish Cooperative cage, used for growing oysters in deep water.

A 2006 study of aquaculture in Waquoit Bay by WHOI’s Marine Policy Center found that 500 oysters and quahogs removed 0.1 kilograms of nitrogen per liter from the water, and an additional 0.1 kg from the sediment underneath the growing tray per year.

According to Mr. Zweig, one oyster, on average, is capable of removing 0.65 milligrams of nitrogen per year during two years of growth.

If grown on an exponential scale, aquaculture could potentially meet TMDL targets, especially if the inlets to some coastal ponds are also widened.

In a spreadsheet analysis of four coastal ponds in Falmouth facing Vineyard Sound, Mr. Zweig recommends setting aside 8-9% of Bournes Pond, Great Pond, and Green Pond for aquaculture, and about 22% of the heavily polluted Little Pond, in order to meet the state-mandated TMDL’s.

Getting Aqua into the Culture

While these studies may be little more than numbers on paper, Mr. Zweig is working with members of the Falmouth Shellfish Cooperative, four companies that hold aquaculture permits in Buzzards Bay, to turn his hypotheses into action.

The Cooperative is currently working on a proposal to start up aquaculture plots in one or several of Falmouth’s coastal ponds. Not only would a more inland location make it easier for the farmers to get to their oyster cages, the development would also serve as an experiment on the potential for shellfish to remove nitrogen.

If successful, the Cooperative estimates that expanded aquaculture operations could create or maintain 165 permanent jobs in Falmouth, while restoring 3,700 acres of shellfish habitat.

An aquaculture site in Buzzards Bay operated by the Falmouth Shellfish Cooperative.

This summer, the Cooperative plans to market their first batch of the Sippewissett Oyster, sold straight from their retail location on Coonamessett Farm. With a fledgling mechanism already in place to put Falmouth’s seafood on the map, the oyster farmers say there is much more room to expand.

In Mashpee, Shellfish Warden Richard York hopes to build on the success of an aquaculture program he started in Mashpee River. The Mashpee Enterprise reports that Mr. York is writing a $75,000 grant to purchase, propagate, and plant 10 million quahog seeds in Waquoit Bay. Quahogs, he says, are ideal for aquaculture because of their resistance to predators.

Even if only half of the quahogs survive to maturity, the initiative will generate up to $750,000 in revenue, enough money for 15 shellfishermen to make a decent living, estimates Mr. York.

It may just turn out that doing the right thing for the environment is also good for the economy– and for our appetites.

The downside of aquaculture

However, the simple solution is not always the easiest. As Cape Codders know well, changes intended to solve environmental problems (think wind turbines) often come with a serious backlash from stakeholders.

The Marine Policy Center quantified the costs and benefits to aquaculture not only from the nitrogen removal angle, but also from the point of view of recreational users of Waquoit Bay.

Due to the potential “aesthetic costs” caused by exposed aquaculture gear at low tide, as well as decreased area for boating, the Marine Policy Center estimated that 1.5% of the head of Waquoit Bay could be used for aquaculture without negative consequences.

One additional issue that aquaculture does not address is the need for a wastewater solution that removes not only nitrogen, but a range of “contaminants of concern” from products consumed and eliminated by humans, now concentrated in your drinking water.

A typical composting toilet: the only difference is the pipe.

Even if shellfish were capable of filtering and sequestering aspirin, Viagra, and shampoo chemical residues from the water, would that solve the problem? (And would you want to eat them?) Or does it just point to a larger question: why are we contaminating fresh drinking water with our waste?

In my humble opinion, we need a variety of options to deal with our wastewater worries. If it is not conceivable to place aquaculture operations in coastal ponds on the scale necessary to remove the entire nitrogen load, it would be wise to eliminate the main cause of the contamination: septic tanks.

Even on a small scale, aquaculture can likely eliminate nitrogen released from non-point sources, namely fertilizer and road run-off. And by installing household composting toilets, we would eliminate at least half of the nitrogen load, while also pre-empting contamination by other, potentially very harmful, chemicals.

Earle Barnhart and Hilde Maingay, whose nonprofit organization, The Green Center, is the successor to the New Alchemy Institute, is concerned that the “big pipe” solutions being discussed by a town committee are inefficient and expensive ways to reduce nitrogen loading to Falmouth’s coastal ponds.

The husband and wife team have compiled nine options that residents can undertake to eliminate nutrients from wastewater. They suggest that a feasibility study be conducted to see how much nitrogen would be eliminated, and at what cost, under each scenario.
“With a great variety of options available right now, home-based systems can be designed to respond to the specific needs of each individual residence or area of concern, require very little design time or costs, can be installed immediately, and have a great degree of inherent flexibility,” wrote the couple in a five-page handout they e-mailed yesterday to Town Meeting members.

• Residents can reduce their nitrogen contribution by using low-nitrogen and phosphorus-free soaps, cleaners, and detergents.
• Eliminating the use of chemical fertilizers and garbage disposals would also reduce the amount of nitrogen in the waste stream.
• Noting that car exhaust and road runoff is a significant source of nitrogen deposition to estuaries, residents can reduce their mileage or switch to a hybrid vehicle.
• On a townwide level,  Falmouth could collect food waste separately from garbage to make compost, thereby using the nitrogen and other nutrients in food as fertilizer.

For those who think it is too hard to incorporate these tips into their lives, Hilde and Earle are living examples. They own a composting toilet, which they say is inexpensive and easy to maintain. As professional landscapers, they use compost and organic fertilizers, and at home they feed food scraps to their chickens and use plant-based cleaning products.

The Bigger Picture

A large-scale oyster aquaculture project could clean up Falmouth's coastal ponds, create jobs and increase local food production

Drawing from the expertise of farmer and aquaculture researcher Ronald J. Smolowitz and Woods Hole resident Ronald D. Zweig, an aquaculture specialist for the World Bank, Hilde and Earle recommend using oysters as  natural filters for nitrogen, and widening the inlets of coastal ponds to increase tidal exchange.

A centralized sewer system, while effective at removing nitrogen, comes with a high cost and long lead time to design, construct, and operate, the authors wrote. In terms of water and energy consumption, it is also inefficient.

Purifying water for drinking, then polluting it with human waste, and cleaning it again is inefficient. Transporting large volumes of water from a supply source to a pumping station, to homes, to a sewage treatment plant, and finally to a discharge area is inefficient.

A variety of sources contribute nitrogen to groundwater, but a majority leaches from underground septic tanks

If wastewater treatment was viewed as a “closed-loop” system, the nutrients it contains could be recovered, treated, and used as organic fertilizer, say Hilde and Earle.

Composting toilets

A composting toilet: the only difference is the pipe

The waterless composting toilet is one of the options Hilde and Earle propose for further study.

It looks like a regular toilet, without a pipe. A fan ensures that odors are released through a pipe in the roof, requiring as much energy as a 60-watt bulb.

“The lower the technology, the less likely it is to fail,” said Hilde.

“That’s right,” said Earle. “Gravity never breaks down.”

The holding tank of a Clivus composting toilet

Collection requires a basement storage tank for solid waste, which is typically removed four times a year.

Though current health codes require off-site disposal, the sterilized waste could be used as commercial fertilizer or at home for non-food crops.

Urine-diverting & packaging toilets

Another option is a urine-diverting toilet with an optional waterless urinal.

With this technology, naturally sterile urine is collected in a basement storage unit, where it can be collected for fertilizer, or be processed in a septic or sewer system.

Hilde and Earle also propose a few options for using waterless packaging toilets and urinals. These options would require a commercial contractor to collect waste “packets,” which can be sterilized and composted to create fertilizer.

The British-designed "Loowatt" toilet was originally built with the waste disposal needs of developing countries in mind.

Alternatively, the packets may be incinerated, either at home or off-site—not unlike throwing out diapers, Hilde noted.

The waste packets can be used in a bio-gas digester, which produces methane gas while killing off pathogens.

The result is a potent fertilizer suitable for edible crops.

Alternative Cost-Benefits

Based on each of these options, traditional toilets do not necessarily have to be replaced. With each of these options, a home would have to keep its septic tank in order to process the “gray water” from the kitchen and laundry.

They suggest studying the costs and benefits of maintaining the current septic treatment at most homes, with the addition of aquaculture and the widening of coastal inlets.

Jobs, food, and fertilizers could be created from this endeavor, whereby not only the oysters, but also the wastes and the macro-algae that grows around them could be harvested as fertilizer.

“Why don’t we try it  and see how much [nitrogen] is removed by reducing our inputs, then we can go to the next step?” asked Earle.

An Ecological Treatment System

This schematic by Ron Zweig proposes a centralized treatment system based on John Todd's ecological design principles

Another option is to install a centralized treatment plant with ecological principles in mind.

In this design, wastewater is treated with a biogas digester that releases methane, which can be used as energy to run the system– or cook food or heat a home.

The primary-treated water is then filtered through aquatic plants and wetlands, where the nitrates decompose and are consumed by beneficial bacteria. These aquatic plants may be composted, and the treated water can be reused to irrigate trees and non-edible plants.

Recognizing that not all residents would be comfortable installing an alternative toilet in their homes, Hilde noted that it will take serious study, modeling, and public outreach for people to understand that the systems are safe and just as effective as traditional toilets.

“We assume that we’re incapable of handling our own waste. That’s a really bad assumption,” she said.

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.