Design Considerations

The Sanctuary is an ecological education and spiritual life center that welcomes the public in small groups. The capacity of the facility is currently set by zoning regulations:

•Maximum: average of 20 visitors per day

oOnce per month: 30 people per day

oThree times per year: gatherings of maximum of 100 people.

The capacity and sizing analysis for the composting toilet considers the zoning constraints as the upper limit of bathroom need and use at The Sanctuary. The analysis includes the following additional factors:

•Estimate of bathroom use based on a Visitor Use Profile developed with regard to the zoning constraints.

•Total availability of bathroom resources including the composting facility, temporary Porta-Pottis installed for larger events, the existing two bathrooms in the main residence on the property.

•Estimates for volume of liquid and solid matter introduced into the composting toilet including the cover materials used to eliminate odors.

Composting is microhusbandry; specifically, the use of microorganisms along with soil, moisture and oxygen, to biologically decompose organic residues, including humanure, into soil, specifically, humus. Humus is a stable material which is critical to soil fertility and to soil’s ability to retain moisture. It also releases nutrients essential for plant growth, helps to balance soil pH, and supports microbial populations that add life to the soil. The composting process requires moisture, oxygen, temperature (and time), and a good nitrogen/carbon (C/N) ratio (approximately 30/1).

                                       

                                          This diagram illustrates the composting toilet design and layout.

Key design elements include:

(1) Curing compartment has an inclined floor (“clivus” is Latin for downward sloping surface) which allows the humanure and other organic residues to pile up while draining liquid towards the front or toes of the structure.

(2) Manually-operated misting system to add moisture to the top of the pile.

(3) Access hatches on the top and front of the curing chamber to allow for easy access in raking and removing the humus pile.

(4) Mechanically-drafted air shaft for the curing chamber to allow for adequate ventilation.

Estimated usage

The capacity analysis relies on a Visitor Profile and maximum

usage provided by the zoning constraints:

•Visitor Profile:

oWeekdays: 5 people per day maximum

oWeekends: 10 people per day

•Zoning Maximums:

oMonthly (1x per month): 30 people

oAnnually (3x maximum): 100 people

Based on the Visitor Profile and the Zoning Maximums,

the total Person Visits per year is calculated to be 2,850.

Project Specifications

Composting containment structure for the composter: 4’ by 4’

by 4’ shoe-shaped rectangle made of cinder block, with

inclined floor, vent, misting system, access doors for raking

and removing humanure, and a liquid collection device via drain at the lower end.

Design specifications are derived from the industry standard Clivus Multrum toilet. Abby Rockefeller, co-founder of that company and a world-expert on composting toilets and sustainable water treatment, has advised on the critical design constraints. The design and size of the composter is essentially the same as the Clivus Multrum toilets used in Gillette Castle State Park.

The composter itself, or curing chamber, is enclosed in a 14’ by 15’ deck with a small building structure encasing the toilet in an “eco-temple,” with ramp, door and wheelchair-accessible interior space.

Sizing & Capacity

•Curing compartment is 60 cubic feet - to allow for approximately three years of capacity and complete digestion of the organic residues prior to needing to be removed.

•Note: no heat sources are needed provided enough time is allowed for digestion;

Use and Maintenance

A Clivus-style composter requires little routine maintenance, but does require a general mindfulness about the conditions of the organic matter in the curing chamber. The Executive Directors of the Sanctuary will be responsible for monitoring the composter and for periodic maintenance. Basic maintenance items include the following:

(1)Odor control - After each use of the toilet, the humanure must be immediately covered with a clean organic material to eliminate unpleasant smells and to trap necessary oxygen in the pile. The covering material can be sawmill sawdust (vs. lumber yard sawdust which is kiln-dried and therefore biologically inhert), peat moss or leaves. A small container and instructional directions for use will be provided for visitors and monitored by the Executive Directors.

(2)Removal of humus – The size of the curing chamber will allow the composting pile to fully decompose before any humus needs to be removed. Based on estimated daily use, it should take a minimum of 5 years, and upwards of 10 years, before any humus needs to be removed from the composter. When removed, this stabilized organic matter will be used to fertilize non-edible plants and trees at the Sanctuary.

(3)Removal of liquids – The drain at the foot of the chamber will collect liquid run-off and carry via a hose to a five gallon bottle for eventual use as high-quality liquid fertilizer on non-edible plants and trees at the Sanctuary. Given high rates of evaporation, this process should take between 5 and 15 years to fill the bottle.

(4)Sanitary facilities – Antibacterial handwipes and paper towels will be provided for visitors to the eco-temple. Supplying these, as well as routine cleaning of the eco-temple enclosure will be the responsibility of the Executive Directors.

Notes on the Ecology of Composting Toilets

Many sanitation experts believe that standard toilets are poorly

designed technologies. In their seminal book Natural Capitalism:

Creating the Next Industrial Revolution, Paul Hawken and engineers

Amory and L. Hunter Lovins discuss the engineering virtues of the

standard American toilet: “In an effort to make them ‘invisible’ a

toilet mixes pathogen-bearing feces with relatively clean urine.

Then it dilutes that slurry with about 100 times its volume in pure

drinking water, and further mixes the mess with industrial toxins in

the sewer system, thus turning ‘an excellent fertilizer and soil

conditioner into a serious, far-reaching, and dispersed disposal problem. Supplying the clean water, treating the sewage, and providing all the delivery and collection in between requires systems whose cost strains the resources even of wealthy countries, let alone the 2 billion people who lack basic sanitation.”

Composting toilets, now being used in parks all over Connecticut, offer restroom service without the need for expensive wastewater treatment. They are safe, less odorous (really no smell whatsoever) than conventional toilets, and an invaluable educational tool for helping people to appreciate, like in olden times, the agricultural value of human waste. Embodying the ecological principle that waste=food, they are the most advanced technological expression of sustainability, and cheaper than conventional toilets. The only barriers to this ultra-rational technology are modernist cultural prejudices about human ‘waste’.

The Sanctuary currently pays about $100 each month to service a “porta-potty”, whose waste is collected and processed at a central sewer treatment plant. The process – centralized sewage treatment - is costly, energy intensive, not as effective as nature’s own way of breaking down harmful pathogens, chemicals and heavy metals through microbial digestion, and produces a toxic waste (sewage sludge) for which there is currently no environmentally safe way to dispose of. This is what you call a high entropy technology, since a lot of energy – both the energy used in the treatment, and the organic energy contained in the human “waste” - are lost in the treatment process. In contrast, a composting toilet helps nature’s own digestive processes to breathe more deeply, closing a nutrient cycle and returning human excreta back to condition the soil. After we complete this project, the Sanctuary will save a cost, reduce its harmful eco-footprint, and replace an ugly industrial artifact with a beautiful shrine which will harmonize deeply with its locale, and ornament the meadow stand of trees like a some strange flower.

Built and designed of mostly local materials, labor, ideas and inspiration, the process of the construction itself will serve as a healthy learning ecology. A learning ecology is a project or situation in which individuals work towards understanding an aspect of their natural, social or economic environment which reveals something fundamental about their collective fate, their values, their identities. When one experiences a larger self, a community-sized self, an invisible bond is uncovered, through which information from a deeper pool of life activity can be transmitted to the individual. This information is a source of energy which empowers the individual to the level of spontaneous, patient, loving commitment to the long-term health of the community. This is where the Sanctuary sees the connection between ecology and spirituality. In this way, our project will illustrate the most progressive vision of sustainability. Sustainability can be mathematically defined as a property of a system: a system is sustainable if its activity is beneficial to the sub-systems contained within it and the macro-systems within which it is contained.

For information about the design, specifications or engineering calculations, call Michael G. Harris, PE at 860-873-8989. To see the project, please contact Justin or Jen at the Sanctuary at (860) 319-1134.