Portable Composting Toilets for Multi Day Events

The Cloacina Project with design and implementation from PNCA’s graduate students in Collaborative Design created an open source hardware platform for toilets, urinals, hand sinks and privacy screens for portable low cost dry toilets. Recognizing that hardware is only half the problem the PNCA students addressed the user interface by creating a training protocol, help line using GroupMe and signage to assure the safe and hygienic conditions for the users.

The toilets: The toilets use one 55 gallon drum cut in to two pieces to act as the throne that shields the 15 gallon collection drum underneath the toilet seat and the cut off piece acts as a step up to the throne. Materials required include a 55 gallon plastic drum, a 15 gallon drum (fiber or plastic), nuts, bolts and metal brackets. The total cost were $43/toilet. This includes the price of buying hazardous material certified plastic liners because we chose fiber drums as our collection vessel. We paid $8 to 10 per 55 gallon drum. After a user uses the toilet they are encouraged to put a scoop or two of coffee hulls on top of their deposit. Our motto was ”if you can see it, we can smell it.”

The urinals: The urinal design was not as elegant as the toilet design though proved functional during the convergence. The urinal is a simple funnel mounted to a privacy screen made from a cut up 55 gallon drum and costs $47 per unit. For odor control their is a ping pong ball in the base of the funnel that allows urine to flow in but seals the pipe into the urine barrel when not in use (>see DIY urinal explanation).

The hand sink: The hand sink is a modification of a Finish design called the “andy handy” and cost less than $6 per unit.

The privacy screen was designed by Dave Laubenthal and Morgan O’hara and implemented with help from the across the Collaborative Design MFA program. Each structure was made from lashing bamboo with zipties. The structure included one stall for a urinal, two for Step Up toilets and one stall with a Sit Down toilet and a hand sink. A hand sink hung outside each station.

Basic Design Principles

Our goal was to design a private portable composting restroom that would:
collection method
-have no offensive odors
-commode can support users and provide solid connection to the floor
-connects commode directly to composting chamber
-prevents user contact with human wastes during normal operation and failure
-free of corrosive parts, rough or sharp edges, or other hazards which could cause injury to persons adjusting, servicing or using device.
-all access ports are sealed to prevent the infiltration of pests
-be acceptable to users

compost chamber
-prevents infiltration of rainwater and groundwater
-provides adequate access for regular service and removal of humus

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Emergency Sanitation Workshop This Saturday

We'll be doing a 45 minute workshop on Saturday June 2nd @ 2pm at King Elementary School as part of Resilience PDX.org
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