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UCLoo Festival 2013


Remembering the 2013 festival of technologies, ideas and debate about sanitation in London


Composting Toilets and the Coast Guard: an unlikely love story

By ucft590, on 10 September 2013

The hull of a steel deck barge is one of the last places I would like to be in the sweltering August heat in Virginia. Yet this is where I found myself during the summer of 2009 while I installed the below-deck components for the vessel’s two composting toilets. The barge was not yet in the water, perched on steel beams alongside the shipyard’s waterfront construction area, so I thankfully didn’t have to contend with the water’s movement. However, it wasn’t the most ideal of building situations. Getting to the underside of each toilet was an adventure in itself: I had to crawl into the hull through one of the top deck hatches then navigate through the maze of steel frames that formed the structure of the barge. Since there was a temperature difference between the interior of the hull and the warm, humid exterior air, beads of condensation continually formed within the hull. Working inside the cramped and dark compartments, illuminated only by my LED headlamp, I felt like I was spelunking in a futuristic cave.

The Learning Barge

The Learning Barge

As the Project Manager for a sustainable, floating classroom and field station called the Learning Barge, I found myself in some unusual and wholly unimagined situations during the design/build process from 2007 through the vessel’s first operation season in 2010. The Barge was conceived as a demonstration tool for non-profit The Elizabeth River Project, to educate students and adults about their local watershed along the Elizabeth River, one of the most polluted tributaries of the Chesapeake Bay. It showcased a wide range of recycled products (reclaimed road signs were used as cladding), sustainable strategies (a rainwater collection feeds a bio-filtration station), and renewable energy systems (wind turbines and photovoltaic panels provide power). Since we wanted to feature a number of green technologies, the integration of composting toilets was essential for the Barge’s “head” (the name for a toilet on a boat, traditionally named since they were located at the head of the vessel so that passing waves could clean the drainage pits). Although composting toilets are becoming more common for personal watercraft, they are rarely used on commercial or industrial vessels.

Marine toilets are inherently different from their land-based counterparts since they do not have the option of being connected to sewer systems. Therefore most marine sanitation systems are adapted versions of chemical toilets that rely on either a bag system or a ‘pump-out’ for the removal of waste. Neither of these systems are ideal: they utilize toxic chemicals and, until the imposed regulations of the Clean Vessel Act of 1992, it wasn’t uncommon for vessel operators to incorrectly dispose of their waste by simply dumping the chemically-treated contents directly into bodies of water. The toilets of the Learning Barge, two 12VDC Envirolet Waterless Remote Systems, consist of three main elements: a toilet, a composting unit, and a ventilation shaft. The small electrical fans within each of the composting units operate 24 hours a day and 7 days a week, allowing heated air to travel through all six sides of the waste, thereby facilitating rapid evaporation and accelerating the compost process. This is unlike many composting systems, that only have one aeration side (the top). During the regular operational season of the Barge (March –November) the toilets require daily attention: the manual aerator within the composting unit (similar to a rake) needs to be pumped and the blackwater tank needs to be monitored.

I installed two waterless, composting toilets

I installed two waterless, composting toilets

With drawings, product documentation, and a detailed operations manual in hand, complete with instructions for what toilet paper to use and procedures for both the start of the season and winterisation, we thought that Coast Guard approval of our composting toilets would be one of the easiest components of the certification process. Yet the uniformed officers were skeptical:

  • How could we ensure that the system would work?
  • What were we going to do with the waste?
  • Would it smell?

The last question was one of the oddest: toilets on ferryboats are rarely pleasant. Over the course of several site visits, we managed to convince the Coast Guard representatives that composting toilets weren’t such a crazy concept for a vessel. We were using a proven supplier, a sturdy unit, and we had outlined every step within the composting process, including specifications for compost disposal in accordance with the Virginia Department of Environmental Quality (a permit was needed for all compost produced outside of residential settings).  With questions answered, our vessel received certification in September 2009 and later that autumn, the members of the Coast Guard independently toured the vessel and its sustainable systems as part of a training exercise. Today, in the Code of Federal Regulations for vessels, there are a number of composting toilets approved as Marine Sanitation Devices (MSD).

*Please also donate to UCLoo Festival – just £5 or less will help – to make sure the conversation on ecological urban sanitation happens:  http://spacehive.com/ucloofestival2013 But hurry – we must reach our fundraising target by 17th October!

Click here to learn more about the composting toilets used on the Learning Barge:


Click here to explore the current environmental endeavors of the Learning Barge:


You can also learn more about the design/build process of the Learning Barge: