Concentration of CO2 in the Atmosphere

Composting Toilets Evolve

The Relationship Between Water Conservation and Watershed Health

The original portable porta-potty image from GET, Aug. 15, 2011. All images courtesy of Ben Goldberg.

Ben Goldberg

A previous G.E.T. article, published in issue 9, Aug. 15, 2011*, described portable composting privies as a greener option to porta-potties. Since that time, there have been a number of inquiries about how the privy functions, questions about urine diversion in general and the present state of composting toilets. This article is a response to those questions and also offers an update on some of the newer versions of composting toilets, and some rationale for the technology.

There is a variety of new composting toilets emerging for use as a result of consumer and ecological demands. The most recent innovation is urine diversion. To say it is recent or an innovation is slightly inaccurate, since that’s the practice of most of us mammals. But to adapt innovative toilet technology to that principle is becoming a trend. In fact, one of the global trend-setters, The Rich Earth Institute, is located right here in Vermont. Rich Earth has been developing protocols and equipment for collection, stabilization, and reuse of diverted urine as a locally sourced fertilizer since 2011 and is helping to establish forward-thinking design and permitting policy for the next generation of bathroom users. Rich Earth is influencing the way we will be going to the loo in the future to reflect a water-conscious global population, and the need to conserve a dwindling global supply of phosphorus.

On site at the Garlic and Arts Festival, Orange, Massachusetts

Keeping the nutrients in pee out of the waste stream, where they then become unchecked pollutants, also conserves the potable water that would otherwise flush them away. Nutrients escaping from septic systems and waste treatment facilities in the Long Island Sound watershed, for example, with communities along the Connecticut River having a few of the larger ones, are identified as a major contributor to the Long Island Sound oxygen-deprived dead zone.

To collect pee for reuse requires some user participation. In Brattleboro, VT, DIY contributors voluntarily fill handy containers which they transport to a local Rich Earth collection depot and vie for the largest amount contributed at the annual “Piss-Off” contest and celebration. Local contributors are the major source of supply for Rich Earth’s research and stabilized fertilizer. Rich Earth also collects pee at festivals and events in their Pee-Only porta-potties and four-place stand-up stations.

One can also find manufactured toilets designed specifically for urine diversion. The seat – or as I enjoy calling it, the user interface – is divided into two sections. The front portion is a human-anatomy-friendly funnel that connects to a collection vessel below via dedicated tubing. The, um, rear end is a larger hole that can either incorporate a chute as a pathway for the solids to enter a composting toilet by gravity, or a flushing bowl that connects to septic or sewer. Isolating the liquid for reuse accomplishes a number of goals, all of equal value. Roughly eighty percent of the nutrients that would otherwise become environmental contaminants, are captured, and become easily accessible for reuse. They remain uncontaminated by fecal pathogens. You save large volumes of potable flush water, thus reducing the burden on your septic system, ground water, or local sewage treatment plant, all while contributing to overall ecosystem health. Reusing the nutrients as locally sourced fertilizer contributes to local food security and reduces dependence on fossil fuels used to manufacture and transport commercially made products from agri-giant corporations.

Full Circle Throne

Vermont is also home to one of the newest composting toilet products on the market. Full Circle Composting Toilets from Putney, diverts urine for reuse, and collects solids for composting in interchangeable storage bins down cellar, below the finely crafted wooden throne outfitted with a Separett seat.

Combining urine diversion technologies with existing non-UD composting toilet systems allows for composting the solids and capturing the liquids for reuse. For example, a Separett or Full Circle commode with a Phoenix Composting toilet provides a very functional hybrid system.

Other products that are emerging onto the scene that use diversion design on location are the composting privies made in Sunderland, Mass by the Privy Counsellors. Made to order, they offer an aesthetically pleasing ecological alternative to the porta-potty, the structures are built to last using artisan-quality crafting – aka Perma-Potty. They can be trailered to a temporary or more permanent site and provide an alternative to sites with no basement or crawl space. They are currently in use in area community gardens, farm schools, farmer’s markets, and other outdoor public and private gathering places, and homesteads. They are consistent with the ecological agricultural theme of many of their sites.

The most recent ADA-compliant privy at a future farm school in eastern Massachusetts.

The privies use a Separett diverting seat and modified carboy urinals for liquids, and a batch collection bin for solids. Each batch gets transferred when full to a long-term vented sequestering bin for the duration of the composting process. When the sequestering bin fills, it is capped off and inoculated with composting organisms to facilitate the process. Another bin is started while the original one composts. A pail full of mature compost or healthy topsoil are good choices for starter organisms. Because the salty and acidic urine has been separated, composting worms can also be added to the sequestering bins to help facilitate the composting process. Urine can also be composted in dedicated sequestering bins as a treatment method if the high-nitrogen urine is mixed with carbon rich bedding such as pine shavings or crushed leaves in the appropriate proportions, and starter organisms are added.

The notion of composting toilets and now, urine diversion, is a stretch for some. For the many others with whom I’ve spoken about ecological sanitation and who do not already have buy-in, it instantly makes obvious sense. More and more people are becoming aware of the relationship between water conservation and watershed health, and the personal choices we make about how we manage our poo and pee. In the same way we are taking a good hard look at our food, transportation, consumer, and energy choices, we are being called upon to take the same look at our bathroom habits.

Ben Goldberg has been working with worm composting and composting toilets for over 30 years, because he recognizes the importance of healthy soil and clean water. He lives and works in the Pioneer Valley of western Massachusetts, in the Connecticut River Watershed.

Links and websites:

*Compost Toilets Go Portable –

The Rich Earth Institute –

Nutrient Networks –

Other manufactured UD products:


Ecoflush and Ecodry –

Separett Villa Series –

Full Circle –

Phoenix Composting Toilet Systems –

Perma-Potties –

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