MONITORING COMPOST TEMPERATURE
Figure 8.7 shows the rise in temperature of humanure compost piles (feces, urine, and food scraps) which had been frozen all winter. The compost consisted primarily of deposits from the sawdust toilet, which contained raw hardwood sawdust (just enough to cover the material in the toilet), humanure including urine, and toilet paper. In addition to this material, kitchen food scraps were added to the pile intermittently throughout the winter, and hay was used to cover the toilet deposits on the pile. Some weeds and leaves were added now and then.
The material was continuously collected over a period of about four months
from a family of four, and added to an existing compost pile. Nothing special
was done to the pile at any time. No unusual ingredients were added, no compost
starters, no water, no animal manures other than human (although a little chicken
manure was added to the pile charted on the right, which may explain the higher
composting temperatures). No turning was done whatsoever. The compost piles
were situated in a three-sided, open-topped wooden bin on bare soil, outdoors.
The only imported materials (not from the home) were sawdust, a locally abundant
resource, and hay from a neighboring farm (less than two bales were used during
the entire winter).
The above compost piles were situated outdoors, in wooden bins, on bare soil. The compost was unturned and no compost starters were used. Ingredients included humanure, urine, food scraps, hay, weeds, leaves, and some chicken manure (on right).The compost was frozen solid, but exhibited the above temperature climb after thawing. Fresh material was added to the compost pile regularly while these temperatures were being recorded on unmoved thermometers. The hot area of the compost pile remained in the upper section of the compost as the pile continued to be built during the following summer. In the fall, the compost cooled down, finally freezing and becoming dormant until the following spring. It is imperative that humanure compost rise above the temperature of the human body for an extended period of time. This is the "fever effect," which is necessary to destroy pathogens. A temperature exceeding 1200F for at least one day is preferred, although lower temperatures for longer periods can be effective (see Chapter 7). The heating of the compost should be followed by a lengthy curing period (at least a year).
"Thank you for a wonderful book on a subject where little information is available. We started using our ‘system' the day after receiving your book. It took about two hours to put together. I wish that more problems that at first seemed complicated and expensive could be solved as simply as this one has with your help." J.F. in NY
From a Christmas letter to friends and relatives:
"I am sorry to say that the solar toilet...never got off the ground. The plans from the book were sketchy and we weren't able to get it to work. It's sitting in the back of the property covered and waiting to be converted into a solar oven. But luckily we read another book [Humanure Handbook] which had an even better method suited for our household. With minimal fuss and expense we set up the system, and it's working great." J.S. in CA
Two thermometers were used to monitor the temperature of this compost, one having an 8" probe, the other having a 20" probe. The outside of the pile (8" depth) shown on Graph A was heated by thermophilic activity before the inside (20" depth). The outside thawed first, so it started to heat first. Soon thereafter, the inside thawed and also heated. By April 8th, the outer part of the pile had reached 50°C (122°F) and the temperature remained at that level or above until April 22nd (a two-week period). The inside of the pile reached 122°F on April 16th, over a week later than the outside, and remained there or above until April 23rd. The data suggest that the entire pile was at or above 122°F for a period of eight days before starting to cool. The pile shown in Graph B was above 122°C for 25 days.
According to Dr. T. Gibson, Head of the Department of Agricultural Biology at the Edinburgh and East of Scotland College of Agriculture, "All the evidence shows that a few hours at 120 degrees Fahrenheit would eliminate [pathogenic microorganisms] completely. There should be a wide margin of safety if that temperature were maintained for 24 hours." 2
The significance of the previous graphs is that they show that the humanure compost required no coaxing to heat up sufficiently to be rendered hygienically safe. It just did it on its own, having been provided the simple requirements a compost pile needs.
THE SAWDUST TOILET ON CAMPING TRIPS
Humanure composters have tricks up their sleeves. Ever go on a week-long camping trip or to a camping music festival and hate using those awful portable chemical toilets that stink? If you have a humanure compost bin at home, simply take two five gallon buckets with you on the trip. Fill one with a cover material, such as rotted sawdust, and put a lid on it. Set it inside the empty bucket and pack it along with your other camping gear. Voila! One portable composting toilet! When you set up your camp, string up a tarp for privacy and set the two containers in the private space. Use the empty container as a toilet, and use the cover material to keep it covered. Place a lid on it when not is use. No standing in line, no odors, no chemicals, no pollution. This toilet will last several days for two people. When you leave the camp, take the "soil nutrients" home with you and add them to your compost pile. You will probably be the only campers there who didn't leave anything behind, a little detail that you can be proud of. And the organic material you collected will add another tomato plant or blueberry bush to your garden. You can improve on this system by taking a toilet seat that clamps on a five gallon bucket, or even taking along a home-made toilet box with seat (as shown in Figures 8.3 and 8.4).
A SIMPLE URINAL
Want to collect urine only? Maybe you want a urinal in a private office, bedroom, or shop. Simply fill a five gallon bucket with rotted sawdust or other suitable material, and put a tight lid on it. A bucket full of sawdust will still have enough air space in it to hold about a week's worth of urine from one adult. Urinate into the bucket, and replace the lid when not in use. For a fancy urinal, place the sawdust bucket in a toilet cabinet such as illustrated in Figures 8.1, 8.2, 8.3, and 8.4. When the bucket is full, deposit it on your compost pile. The sawdust inhibits odors, and balances the nitrogen in the urine. It sure beats the frequent trips to a central toilet that coffee drinkers are inclined to make, and no "soil nutrients" are going to waste down a drain.
The thought of carrying buckets of humanure to a compost bin can deter even the most dedicated recycler. What if you could situate your toilet directly over your compost bins? Here's some reader feedback:
"I finally write back to you after 2 1/2 years of excitingly successful and inspiring use of humanure methods applied to a ‘direct shitter' compost. We indeed built a beautiful humanure receptacle 10 feet long, 4 feet high and 5 feet wide, divided into two chambers. One chamber was used (sawdust after every shit, frequent green grass and regular dry hay applications) from May 1996 until June 1997, then nailed shut. We moved to the second chamber until June 1998 - when with excitement mounting, we unscrewed the boards at the back of the "Temple of Turds" (our local appellation) and sniffed the aroma...of the most gorgeous, chocolate brownie, crumbly compost ever SEEN. Yes, I thrust my hands fully into the heavenly honey pot of sweet soil, which soon thereafter graced the foundations of our new raspberry bed. Needless to say, the resulting berries knew no equal. Humanure and the potential for large-scale . . . even a city size composting collection (apartment building toilets into a central collection dumpster), along with the crimes of the so-called "septic system," has become one of my most favored topics of conversation and promotion. Often through direct exposition at our farm. Many thanks for your noble work of art and contribution to this stinky species of ape." R.T. in CT
The Straw Bale House in Ship Harbor, Nova Scotia, Canada, built in 1993, employed an outhouse until 1998 when a composting toilet was built. The toilet allowed for the direct depositing of humanure into compost chambers underneath the house. Designer/builder Kim Thompson provides feedback:
"Having heard and experienced mixed success with commercial composting toilets, it was exciting to read the Humanure Handbook and have systems detailed which reinforced ideas that had only existed with me intuitively before. I did a lot of research on the subject, but as far as I could make out, the indoor system I wanted to try hadn't been done before. After several phone conversations with Joe Jenkins, his encouragement, and a sharing of plans, I went ahead with the project. Two concrete chambers, three feet high by five feet square, with four inch thick walls, were built on a six inch gravel base with a French drain, underneath the house. In the bathroom above, a wooden box was fitted with a standard toilet seat as well as a compartment for sawdust storage. All kitchen scraps, straw, and some garden compost were added regularly to the compost chambers, as well as the sawdust cover material. Red wriggler worms were added as well. Two and a half residents used the toilet, and the first chamber filled in six months.
Because there wasn't a good starter base of organic material, and because there was no drain (one was added later), the compost was, for many months, a sloppy, ineffectual mess. I now recommend layering the following materials in a composting chamber before it is used: one foot of straw, six inches of sawdust, a couple buckets of compost as a starter, one foot of leaf compost, and three inches of sawdust (or something like that depending on availability of local resources). Be sure to include a drainage system from the chambers to prevent a build-up of urine.
Make sure there are screens over the access doors to the chambers which can be easily removed, as easy access to the chambers makes it more likely that they will be maintained and monitored regularly. In a northern climate the chambers need to be constructed in such a way as to insure that they won't heave with the frost. It is important to insulate the chambers during the winter months to optimize conditions for thermophilic activity.
The learning curve on how to maintain and use the system efficiently has been steep. It is like learning how to make bread, easy when you know how. Smell has been the biggest problem so far. We have tried three different ways of venting and find that it still smells on occasion. Venting is currently done through a stove-pipe flue. I intend to install a small photovoltaic fan that will either draw air into the stove-pipe or directly outside through a vent. I injured myself over the winter and found that maintenance of the composting toilet system for a single person with a disability was difficult, especially hauling the bags of frozen sawdust cover material into the storage area. I had thought that establishing thermophilic activity in the second chamber over the winter months would be difficult, but a couple buckets of compost from the first chamber activated the new chamber almost immediately. The draft created by the toilet seat hole while in use, especially in the winter, has been variously described. A simple way of sealing the seat when not is use needs to be developed. We have been using a piece of polystyrene foam with a handle which sits in the box under the seat. It works, but isn't elegant.
I love the fact that I don't have to deal with a septic system and that the compost produced will help feed my family. The composting toilet complements well my work with low impact, natural building systems. Many people who contact Straw Bale Projects about construction are also interested in the compost toilet alternative."
For more information contact Kim Thompson, Straw Bale Projects, 13183 Hwy #7, Ship Harbor, NS Canada B0J 1Y0; EMail: email@example.com
Source: The Humanure Handbook. Jenkins Publishing,
PO Box 607, Grove City, PA 16127. To order, phone: 1-800-639-4099.