(Part 1 is interesting, too!)

There’s no easy answer to Cape Cod’s sanitation conundrum. Some solutions are expensive and invasive while other — cheaper — options haven’t yet been perfected for community-sized applications.

Affordable, nutrient-recovering systems

Bryan Horsley, project assistant at the Massachusetts Alternative Septic System Test Center (MASSTC), has solutions that might be the most promising and least expensive options for Cape Cod. At MASSTC, he and the staff are looking into two types of toilets. The first type is urine-diverting, whereby urine is diverted and collected separately using specially designed toilet fixtures that are plumbed to a storage tank below, effectively capturing 80% of nitrogen at the source.

The second type is a composting toilet that accepts both urine and feces, along with wood shavings to absorb moisture. The toilet is waterless and relies on gravity and other processes that are similar to a garden composter. Nitrogen and phosphorus are conserved in the final product (compost!), which is removed through the chamber access door. Because urine and feces make up about 90% of the nutrients in residential wastewater, this system is extremely effective at keeping those nutrients on the earth, rather than in surface water.

Horsley and colleagues are hoping to clear the regulatory pathways so that urine can be collected on a large scale and turned into fertilizer. “When we first started talking about using urine diverting and composting toilets to capture nutrients, there was resistance,” admits Horsley. “There’s social stigma and a perception that the people asking us to do this are on the fringe — tree-hugging hippies. But now it seems like both the public and regulators have warmed up to the idea.”

Once urine is collected it can be processed in various ways to assure safety and to make the fertilizer products that farmers and landscapers need. Brightwater Tools, the for-profit spinoff of the Rich Earth Institute in Brattleboro, Vermont has produced a series of tools that are designed to make urine into fertilizer. Their pasteurizer rids the urine of pathogens; a struvite reactor can harvest the phosphorus as a solid; the freeze concentrator can pull out pure water to increase the nutrient concentration; and the carbon filter can remove any remaining unwanted contaminants like pharmaceutical residuals. Another Vermont-based company called Wasted* is marketing a urine-derived fertilizer product called WeeBloom, which has been registered by the Massachusetts Department of Agricultural Resources.

Horsley estimates that installation of urine-diverting toilet systems might cost $5,000 to $15,000 per home on Cape Cod. “There’s interest and a lot of data about how many nutrients can be removed at a low cost,” he says. MASSTC partnered for two months with the Green Center, Inc. and Wasted* on a pilot urine-collection project of 41 Cape Cod households; each produced an average of 29 gallons of urine over two months.

Now MASSTC and its partners¹ are preparing to install urine-diverting systems in 25 households to monitor for two years. They’ll monitor system performance, measure the amount of nitrogen and phosphorus removed, and evaluate whether these systems can help meet watershed water-quality goals.

What about that composting?

Yet another option is demonstrated by two vacuum-flush toilets at MASSTC’s new Clean Water Center. The toilets use 0.5 liters of water per flush, sucking paper, pee, and poo into a container of wood shavings where everything is aerated and composted at a high temperature. The resulting compost, once ready, is a rich soil amendment that can nourish the many flower beds around the site.

These toilets achieve on a micro scale what Compost for Good is developing on a larger scale. Based in Lake Placid, NY, the organization recently opened the Human Urine Research and Demonstration Facility. Co-founder John Culpepper has designed a rotating drum composter that’s 20 feet long and 4 feet wide. Culpepper mixes diverted urine and other nitrogenous feedstock like food scraps and brewery mash with carbon sources (think wood chips and densified wood pellets). As the tunnel rotates, it aerates the mixture and the microbes naturally raise the temperature. After maintaining the mixture above 131˚F for 15 days, voilà: compost.

So far, Compost for Good has turned about 2,000 gallons of urine into compost. The process denatures all pharmaceuticals that have been tested to date, yet retains nutrients and trillions of beneficial microbiota that benefit plants. Culpepper, who studied the effect of mycorrhizal fungi on plants at Cornell University, says, “I’m the only person I know of who’s doing this.” He wants others to use his recipes and designs, and hopes to collaborate with MASSTC to demonstrate the value of urine composting on Cape Cod. They’d use special toilets that would divert urine to collection tanks until it could be transferred to a composting facility with rotating drum composters.

We’re not there yet…

Two looming challenges that urine recycling projects face are geographically diverse sources and individual choice. Urine sources (us!) are so spread out that collection necessitates transport, and that won’t be solved until communities are designed to recycle what used to be called human waste. “We’re realizing that urine diversion and composting toilets can work,” says Horsley. “Clearly the industry needs to develop. There are not enough pump trucks, not enough urine-diverting toilets, but that’s what we’re trying to do, so we’re ready for large-scale adoption.”

As for individual choice, people can be educated about the need to recycle their pee, but not all will want to adopt urine-diverting toilets, even though they don’t differ much from water-flush toilets. “On Cape Cod, people will have to make major financial choices that might change this social stigma issue,” says Horsley. “They can invest $100,000 per household to sewer, $50,000 per household to use I/A septic, or $10,000 per household to use urine-diverting or composting systems. The latter two options are reliant on regulatory approvals, but we are making progress and I’m optimistic that these will be viable options in the near future.”

1. Many partners not fully described here are helping to solve Cape Cod’s conundrum and educating residents about the options: local municipalities (Town of Falmouth, County of Barnstable, other towns on Cape Cod, and the Islands), the Rich Earth Institute, Michigan State University, Point of Shift, Nutrient Networks, the Green Center (formerly known as the New Alchemy Institute), Deep Pond Preservation Project, Falmouth Water Stewards, Great Pond Foundation, Old Ladies Against Underwater Garbage, Save Mashpee-Wakeby Pond Alliance, Woods Hole Oceanographic Institute/Center for Oceans and Human Health, the National Institute for Environmental Health Sciences, and the National Science Foundation. ↩︎