Cloacina Development Blog » composters

The Emergency Sanitation Handbook

molly — Fri, 16 Dec 2011 22:52:05 +0000

Our students in the Sanitation, Hygiene, and Integrated Technology lab at PNCA have released the first draft of a hands on guide to managing your own sanitation after an emergency. It’s a fun, fresh, illustrated 16 pager that’s bound to save your ass in an emergency. We’ll be doing some final touches on it with the students in January. Until then, we’re just so proud of their work and commitment to providing concise educational materials on such a difficult topic.

Portable Composting Toilets for Multi Day Events

molly — Fri, 04 Nov 2011 23:37:23 +0000

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
-watertight
-provides adequate access for regular service and removal of humus

Compost-heated Greenhouse c.1750

Mathew — Wed, 06 Apr 2011 16:57:59 +0000

Ním Wunnan points us towards the Lost Gardens of Heligan, where they have restored to operation a “pineapple pit,” a compost-heated greenhouse in fashion in the mid-18th century for growing pineapples in Britain. It is, as far as is known, the world’s only operational pineapple pit.

Tuning the Aeration of our Pile

Mathew — Sat, 02 Apr 2011 00:41:03 +0000

We’ve built a compost pile that is designed to be minimally turned and composted in a vessel, so we’re using a blower to get air in, and we need to tune the aeration rate.

Our first problem running aeration tests is to measure the effective aeration of our system. As detailed below, the New Alchemy Composting Greenhouse -our inspiration- doesn’t appear to have done this calculation right. No wonder, when we couldn’t find an accurate low-speed air flow meter, let alone afford one. Even $500 units for HVAC testing weren’t accurate at really low speeds.

So we built our own meter- an inflatable tube that has 1 cu ft volume for every foot of length. It took about 20 minutes, and cost less than $0.20 because I build a lot of balloons and have lots of plastic. The circumference of the tube is 3.545 feet, if you’d like to make one. I like this solution a lot, although using it looks totally ridiculous:

Our Aeration Rate-

We have about 200kg of compost with a volume of almost 1 cu meter (0.94 cu m), and an effective aeration rate of 3cu ft per minute (85 liters). Our maximum aeration rate is therefore 0.43 l/kg/minute. Given our review of existing research, we ran our first test with the fan on continuously. The center of the pile got to above 170 degrees for 4+ days, but the edges barely heated up at all. Although this is fairly typical of a compost pile, we’re hoping to get a broader temperature increase.

Our Next Test

During our next test we’ll decrease the aeration rate to slow down biological activity in the middle, and hopefully allow more heat retention on the sides. This decision would seem to contradict the findings of Yamada, et al, so lets go look at the research!

Forced Aeration according to Yamada, et al (Waste Management):

Yamada, et al got the best results with 2 l/kg/min. We can’t even get that high, and will probably overheat the center of our pile if we increase aeration.

Forced Aeration according to New Alchemy:

Review of the numbers below, but there are issues with their calculation- the rate is somewhere between 0.02-0.62 l/kg/min. From their documentation:

A single 1/15-HP (50-watt) Dayton 2-speed blower rated at 310 cubic feet per minute (8.8 m3/min) at 0 inches static pressure pulls oxygen-rich air from the greenhouse atmosphere and blows it underneath and through the compost. We use the fan at its lower setting where it moves about 190 cubic feet per minute (5.7 m3/min), with power consumption of about 80 watts. This blower is timer-controlled to come on for 15 minutes every 6 hours, or a total of 1 hour every 24 hrs. The compost chamber therefore receives about 12,000 cubic feet (340 m3) of air per day under normal operating conditions.

Pg 9 “The Composting Greenhouse at New Alchemy Institute: A Report on Two Years of Operation and Monitoring” March 1984-January 1986. New Alchemy Institute Research Report No. 3, Bruce Fulford.

Given our blow tests we know that 0″ static pressure is completely unrealistic in a compost pile. At 0″ static pressure we should get 75 cu ft/ min. Under 1 yard of compost we’re getting 3 cu ft/min. New Alchemy’s bins were 25 cu yards, and if they had a mixed density like our compost (about 0.2kg/l), and therefore 3800kg of manure in their bins, given their average aeration rate of 83cu ft/ min (12,000/day) (2350 l/min) they had a rate of 0.62 l/kg/min, if we trust their numbers. If their blower performed like ours (and we have no reason to believe it did) they’d have gotten 7.2 cu ft/ minute, not 190 out of it, and their actual aeration rate could have been as low as 0.02-0.03 l/kg/min.

Diagram of Types of Composting Toilets

molly — Wed, 09 Mar 2011 23:34:12 +0000

Ah, at last I found the simplest illustration of types of composting toilets. It’s from a review of household dry sanitation practices around the globe put out by Toilettes du Monde in France. The full article hasn’t been translated into english yet, but the summary has.

Earle Barnhart & Hilde Maingay on Sanitation Alternatives

Mathew — Tue, 15 Feb 2011 01:14:41 +0000

We received a lovely e-mail from Earle & Hilde, who have been busy illustrating alternative urban sanitation systems that can solve Cape Cod, Massachusetts’ ongoing aquifer poisoning. Great flow diagrams for nitrogen within different systems, these would be a great complement to any presentation on contemporary sanitation practices and the future of sanitation.

Pail Collection and Composting in Skaneateles!

Mathew — Thu, 14 Oct 2010 20:12:11 +0000

This is the longest-running pail collection system I’ve seen in the Western World. Run from 1908-1998 around summer cottages in upstate New York, 5-gallon buckets were picked up from public outhouses and private summer cottages. Sewage was banned to protect the watershed. PDF article here.

Continuous interaction with cottage owners has been essential to the success of this project. Many cottage owners were apprehensive about abandoning a unique and functional waste disposal method that they had used since child- hood. Others voiced concerns about potential odors, mechanical failures, and operation and main- tenance responsibilities.

Also:

The city’s remaining pail service employee has been incorporated into the watershed inspection team, allowing for a more productive use of staff-hours.

What I find most interesting is that despite buying SunMar and other under-seat composters, the need for additional composting was recognized. They built 1-yard bins and empty their toilets into the bins! they could’ve just gone from pails to bins and skipped the expensive toilets.

Now you can Buy

Mathew — Fri, 01 Oct 2010 06:45:09 +0000

Our posters are now up on cloacina.org, along with a buy button.

Illustrating Waste Management Techniques & Options

molly — Tue, 03 Aug 2010 01:55:26 +0000

I’m working on completing a full illustration of Portland’s waste treatment plant and how it works for a series of posters I’m making about the past, present and the very hopeful future for waste management. If you’re interested in non-cartesian representations of physical processes drop me a line, I need all the advice I can get.

DEQ permits Dirthugger

Mathew — Thu, 22 Jul 2010 05:00:49 +0000

Dirthugger, a new Oregon composting company, just got their permit from the DEQ!. Congratulations!