Nyna and I apologize for falling behind on our one blog post entry per week schedule. I have often found the need to make an entry twice as long as originally intended, in order to present all the ideas necessary to make the blog post complete and thorough. I have done my best to avoid giving only enough information 'to make you dangerous'. There may be no more important homestead task to have thorough and complete understanding of than Humanure Composting. The last 3 blog posts have been leading up to this one...Please review the following Blogs: Blog #6 : Sawdust Bucket Composting - Dec 2, 2015 , Blog #7 : Principles of Composting - Dec 9, 2015 and Blog #8 : Composting In Practice - Dec 23, 2015. If you have not read all these past entries, please give them a thorough read before moving forward. I will be assuming familiarity with the ideas presented there.
Humanure Composting follows all the general composting principles presented earlier (Principles of Composting, Wed. Dec. 9th). Humanure can be considered a Fire element in the alchemical framework. Our urine is a very strong Fire substance, in that it contains a very high percentage of nitrogen and other nutrients. Our feces are a weaker Fire substance, in that they contain some amount of organic matter, which relates to the amount of fiber in our diet. This organic matter acts as a Rock (Earth) substance, damping down the Fire brought on by the nutrients our bodies are eliminating. Further dampening is brought on by the sawdust that we use to cover our humanure deposits (Blog #6). Sawdust is a very strong Rock element, having a very high carbon to nitrogen ratio. The proportion of Fire (nitrogen) to Rock (carbon) in any particular bucket of humanure is directly related to the odor it emanates. The more sawdust used to cover urine and/or feces, the more nitrogen is absorbed by the carbon in the sawdust, and the less odor will emanate. Although we generally add one cupful of sawdust to each deposit (and 4 cupfuls at the base of each bucket), whether urine or feces, in practice, urine often requires twice as much sawdust to eliminate (or significantly reduce) its odor than feces do. There is not a strictly right or wrong approach to sawdust covering, you may use more or less than one cupful as your sense of smell requires. It is important, however, to be aware of how much sawdust (Rock) we are using, for the more sawdust used at this bucket stage, will generally transfer to less loose straw (or other carbonaceous material) being needed at the pile building stage.
As mentioned in earlier blog post, we generally follow the procedures set forth by Joseph Jenkins, in his book, The Humanure Handbook: A Guide To Composting Human Manure. As far as beginning a pile is concerned, Jenkins' method is similar to our procedure for regular composting ( Blog #8). However, due to high groundwater on our land, we take extra precautions to ensure that our humanure never comes in contact with our soil. The first precaution that we take is to build all our humanure piles up on pallets. Not only do pallets raise the piles up off the ground, but they create an Air space between the piles and the ground which further ensures that no pathogens will come in contact with our soil. The second precaution we take is to lay down a base of straw bales, on top of the pallets, for each pile. We put down 8 straw bales to form a 4 1/2' x 4 1/2' square with loose straw stuffed tightly into the spaces between bales. These bales ensure that no liquids will leach down onto our ground by absorbing them, and over time, becoming part of the finished compost.
Once the base of the humanure pile is set, we begin raising the walls, one tier at a time, again with straw bales to fully contain the materials we will place inside. Building straw bale walls on the edge of this 4 1/2' x 4 1/2' square, generally produces a 3' x 3' composting area inside (assuming standard straw bale size of 3' length x 1 1/2' width x 1' height). If we have any cardboard, paper, or fabrics to compost, they go down first, where they help with absorption and where they will break down best. Next, we empty the humanure buckets, poo and pee, both of which have been closed tightly with lids. If we have any wood ashes from our woodstove, we spread these over the humanure. Then we add all of the food scraps and other decomposing 'waste', that our kitchen has generated over this same period of time (and also kept stored in closed buckets). Usually, these food scraps generate a much stronger offensive odor than the humanure. Finally, we cover everything with a thick (3" - 6") layer of loose straw. Similarly to sawdust, the more loose straw that is applied, the less odor will emanate from the pile. In general, our humanure piles only release a mild, musky odor (that does not smell much like feces or urine) in the week following the building of compost, and only during the hottest months of Summer. If we did find this musky smell disagreeable, we would add more loose straw.
We then wash our humanure buckets with a mixture of soap, water, bacterial cleaner and 1 Tablespoon hydrogen peroxide. We clean these buckets as we would a flush toilet. The water used for washing gets poured over the compost pile and another thinner layer (2" - 3") of loose straw is spread over that. This now very thick layer (6" - 9") of loose straw covers our food scraps, wood ashes (if any) and humanure deposits, until the next months, when it becomes the base for the next tier of materials. We continue in this manner until we have reached a height of 3', forming a final cubic volume of 3' x 3' x 3', which is equal to 27 cubic feet or one cubic yard. A second very thick ( 6" - 9" ) layer of loose straw is spread on the very top of the pile when we have reached our final height and are ready to let the pile sit.
When we do smell that musky odor, or see steam rising up on a cold morning, we know that our compost pile is active, that the microbes are digesting all the materials we have given them to eat. This is what makes humanure composting such an effective method for eliminating waste. Within that first week of heating up, everything that we have put in is being transformed into something else by the beneficial microbial life in the pile. After a month of composting, it is already difficult to recognize the original materials put in. After one year, it has become something completely different.
Having read our past blog posts, you are familiar with my criticisms of municipal sewage systems. Up until now, I have avoided the topic of rural septic systems. Rural septic systems are not as wasteful as municipal systems, in that the water flushed and nutrients contained in the humanure are generally kept on site, and so, remain available for plant growth on that homestead. Yet, the primary goal of septic systems is similar to that of municipal systems: to move our crap out of our view, and out of our thinking. The septic tank and adjoining leachfield do not transform our humanure with anywhere close to the efficiency of composting. All septic systems, sooner or later, fail, and when they do fail, a costly service, that cannot be put off, is then required to get the septic functioning again.
In addition, to a much lower level of efficiency, rural septic systems are also much less effective at killing pathogens in our humanure than composting systems are. This is due not only to the heat generated by composting, but also due to soil not needing to be added to humanure piles. The pathogens commonly found in human feces have all evolved to propagate themselves when coming into contact with soil (most likely through centuries and millenia of us burying our feces in the ground). When liquid waste from humanure leaves the septic tank and enters the adjoining leachfield , it carries with it the pathogens (which have not been killed in the tank) and brings them in contact with soil, where they can multiply. This is not to say that septic systems are dangerous. A healthy leach field will eventually digest and eliminate these pathogens, too. This short diversion is to point out that rural septic systems function with nowhere near the efficiency or efficacy of composting toilet systems, and to shift over thinking about humanure in a more positive and productive direction.
Two factors will kill pathogens in a compost pile: heat and time. Although, we know our humanure piles heat up (just from placing a hand over the top), I do not poke a thermometer into their centers to be sure that they reach a certain temperature. Not taking temperature, I fall back on time: one year will generally kill all pathogens in humanure compost, regardless of temperature. So, we let all our piles sit for a minimum of one year.
In The Humanure Handbook, Joseph Jenkins describes the "humanure hacienda" that he has built for his compost piles. His 'hacienda' includes a sloping rood to shed rain and snow. Jenkins lives in Pennsylvania, a humid climate within the Eastern Woodlands Bioregion, where it is important, as in other rainy places, to keep excess moisture from leaching nutrients (and potential pathogens) out of the pile and into the ground underneath. Here in Taos, New Mexico, we are up on a high desert plateau, with an average yearly rainfall of 10" - 12" and a very high rate of evaporation. We have found that in this BioRegion, rain and snow are not enough to keep a compost pile continuously active, so we keep our piles open to the moisture that we do get from the Sky, and supplement this by pouring our kitchen wash water over the pile we are currently building.
All of the steps we take do make our humanure composting system both time and labor intensive. Yet, as a whole system, it is working very well for us. Any of you who embark on humanure composting will need to weigh all the factors present in your specific situation, both land factors and climate factors, and address them each appropriately. There is no one single method that will work best for everywhere.
There is one last precaution that we take here. There do exist some pathogens. generally living in tropical regions rather than temperate ones, as well as some within the bodies of seriously ill people, that are more difficult to kill. (For further information on these more resistant pathogens, please refer to Future Fertility, by John Beeby, a publication of Ecology Action, and available through Bountiful Gardens, a mail-order garden supply center in Willits, CA). In these circumstances, a second year of composting will then kill all pathogens, for certain. Since our standard goal has been to become an educational and demonstration center, and since we don't wish to do health and background checks on our visitors, we began, at the beginning, the practice of turning each humanure pile once, after one full year of sitting.
When turning one of our piles, we do not place pallets underneath the turned pile, but we do put down a full straw bale base, and build up straw bale walls as with the original pile. Turning a pile is a good opportunity to check on the composting process, to see how materials have been breaking down. (For details on turning compost, please refer to Blog #8.) When the pile is completely rebuilt, we pour 4 five-gallon buckets of water over it to reactivate and reheat, and further supplement with monthly waterings for the next full year. Finally, after two full years of sitting, we apply this finished compost to our extensive border planting of small trees and shrubs. It is truly hard to believe , by now, what this healthy soil-enriching substance was born from!
For those of you interested in beginning a humanure composting practice, I recommend taking the following steps:
- Become proficient at composting regular garden and yard materials by practicing with them for a minimum of 1 year.
- Read The Humanure Handbook: A guide to composting humanure , written by Joseph Jenkins, thoroughly.
- Find an experienced humanure composter in your BioRegion who is willing to demonstrate to you their techniques, explain their site adaptations, and allow you to participate in the building of a pile.
As always, we are happy and willing to answer all your questions regarding humanure composting and/or any other homesteading topics we have raised. If there is interest, composting is something that we can provide training in here at Living Earth Garden Project, along with these other homesteading skills we have been presenting. Please let us know what your interests are.
With best wishes for a restful Winter!
Gardener Machei
Taos, New Mexico
No comments:
Post a Comment