A Hatchville couple wants the town to consider home-based wastewater treatment options before moving forward with a multi-million dollar, centralized sewage treatment system.
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
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.
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.
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.”
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.
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.
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
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.
Tags: Alchemy Farm, aquaculture, biogas digester, cape cod, composting toilets, Comprehensive Wastewater Management Plan, Earle Barnhart, Falmouth Climate Action Team, fertilizer, gray water, Hilde Maingay, packaging toilets, Ron Smolowitz, Ron Zweig, Sewering, shellfish, The Green Center, Todd Ecological Design, urine diverting toilets, Wastewater, water reuse
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