There are four general ways to deal with human excrement. The first is to dispose of it as a waste material. People do this by defecating in drinking water supplies, or in outhouses or latrines. Most of this waste ends up dumped, incinerated, buried in the ground, or discharged into waterways.
The second way to deal with human excrement is to apply it raw to agricultural land. This is popular in Asia where “night soil,” or raw human excrement, is applied to fields. Although this keeps the soil enriched, it also acts as a vector, or route of transmission, for disease organisms. In the words of Dr. J. W. Scharff, former chief health officer in Singapore, “Though the vegetables thrive, the practice of putting human [manure] directly on the soil is dangerous to health. The heavy toll of sickness and death from various enteric diseases in China is well-known.” It is interesting to note Dr. Scharff ’s suggested alternative to the use of raw night soil: “We have been inclined to regard the installation of a water-carried system as one of the final aims of civilization.” 1 The World Health Organization also discourages the use of night soil: “Night soil is sometimes used as a fertilizer, in which case it presents great hazards by promoting the transmission of food-borne enteric [intestinal] disease, and hookworm.” 2
This book, therefore, is not about recycling night soil by raw applications to land, which is a practice that should be discouraged when sanitary alternatives, such as composting, are available.
The third way to deal with human excrement is to slowly com- post it over an extended period of time. This is the way of most commer- cial composting toilets. Slow composting generally takes place at temperatures below that of the human body, which is 370C or 98.60F. This type of composting eliminates most disease organisms in a matter of months, and should eliminate all human pathogens eventually. Low temperature composting creates a useful soil additive that is at least safe for ornamental gardens, horticultural, or orchard use.
Thermophilic composting is the fourth way to deal with human excrement. This type of composting involves the cultivation of heat-loving, or thermophilic, microorganisms in the composting process. Thermophilic microorganisms, such as bacteria and fungi, can create an environment in the compost which destroys disease organisms that can exist in humanure, converting humanure into a friendly, pleasant-smelling humus safe for food gardens. Thermophilically composted humanure is entirely different from night soil.
Perhaps it is better stated by the experts in the field: “From a survey of the literature of night soil treatment, it can be clearly concluded that the only fail-safe night soil method which will assure effective and essentially total pathogen inactivation, including the most resistant helminths [intestinal worms] such as Ascaris [roundworm] eggs and all other bacterial and viral pathogens, is heat treatment to a temperature of 550 to 600C for several hours.” 3 These experts are specifically referring to the heat of the compost pile.
According to the dictionary, compost is “a mixture of decomposing vegetable refuse, manure, etc. for fertilizing and conditioning the soil.” The Practical Handbook of Compost Engineering defines composting with a mouthful: “The biological decomposition and stabilization of organic substrates, under conditions that allow development of thermophilic temperatures as a result of biologically produced heat, to produce a final product that is stable, free of pathogens and plant seeds, and can be beneficially applied to land.”
The On-Farm Composting Handbook says that compost is “a group of organic residues or a mixture of organic residues and soil that have been piled, moistened, and allowed to undergo aerobic biological decomposition.”
The Compost Council adds their two-cents worth in defining compost: “Compost is the stabilized and sanitized product of composting; compost is largely decomposed material and is in the process of humification (curing). Compost has little resemblance in physical form to the original material from which it is made.” That last sentence should be particularly reassuring to the humanure composter.
J. I. Rodale states it a bit more eloquently: “Compost is more than a fertilizer or a healing agent for the soil’s wounds. It is a symbol of continuing life . . . The compost heap is to the organic gardener what the typewriter is to the writer, what the shovel is to the laborer, and what the truck is to the truckdriver.” 4
In general, composting is a process managed by humans involving the cultivation of microorganisms that degrade and trans- form organic materials while in the presence of oxygen. When properly managed, the compost becomes so heavily populated with thermophilic microorganisms that it generates quite a bit of heat. Compost microorganisms can be so efficient at converting organic material into humus that the phenomenon is nothing short of miraculous.
In a sense, we have a universe above us and one below us. The one above us can be seen in the heavens at night, but the one below us is invisible without magnifying lenses. Our ancestors had little understanding of the vast, invisible world which surrounded them, a world of countless creatures so small as to be quite beyond the range of human sight. And yet, some of those microscopic creatures were already doing work for humanity in the production of foods such as beer, wine, cheese, or bread. Although yeasts have been used by people for centuries, bacteria have only become harnessed by western humanity in recent times. Composting is one means by which the power of microorganisms can be utilized for the betterment of humankind. Prior to the advancement of magnification, our ancestors didn’t understand the role of microorganisms in the decomposition of organic matter, nor the efficacy of microscopic life in converting humanure, food scraps and plant residues into soil.
The composting of organic materials requires armies of bacteria. This microscopic force works so vigorously that it heats the material to temperatures hotter than are normally found in nature. Other micro (invisible) and macro (visible) organisms such as fungi and insects help in the composting process, too. When the compost cools down, earthworms often move in and eat their fill of delicacies, their excreta becoming a further refinement of the compost.
SOLAR POWER IN A BANANA PEEL
Organic refuse contains stored solar energy. Every apple core or potato peel holds a tiny amount of heat and light, just like a piece of firewood. Perhaps S. Sides of the Mother Earth News states it more succinctly: “Plants convert solar energy into food for animals (ourselves included). Then the [refuse] from these animals along with dead plant and animal bodies, ‘lie down in the dung heap,’ are composted, and ‘rise again in the corn.’ This cycle of light is the central reason why composting is such an important link in organic food production. It returns solar energy to the soil. In this context such common compost ingredients as onion skins, hair trimmings, eggshells, vegetable parings, and even burnt toast are no longer seen as garbage, but as sunlight on the move from one form to another.” 5
The organic material used to make compost could be considered anything on the Earth’s surface that had been alive, or from a living thing, such as manure, plants, leaves, sawdust, peat, straw, grass clippings, food scraps and urine. A rule of thumb is that any- thing that will rot will compost, including such things as cotton clothing, wool rugs, rags, paper, animal carcasses, junk mail and card- board.
To compost means to convert organic material ultimately into soil or, more accurately, humus. Humus is a brown or black substance resulting from the decay of organic animal or vegetable refuse. It is a stable material that does not attract insects or nuisance animals. It can be handled and stored with no problem, and it is beneficial to the growth of plants. Humus holds moisture, and therefore increases the soil’s capacity to absorb and hold water. Compost is said to hold nine times its weight in water (900%), as compared to sand which only holds 2%, and clay 20%.6
Compost also adds slow-release nutrients essential for plant growth, creates air spaces in soil, helps balance the soil pH, darkens the soil (thereby helping it absorb heat), and supports microbial populations that add life to the soil. Nutrients such as nitrogen in compost are slowly released throughout the growing season, making them less susceptible to loss by leaching than the more soluble chemical fertilizers.7 Organic matter from compost enables the soil to immobilize and degrade pesticides, nitrates, phosphorous and other chemicals that can become pollutants. Compost binds pollutants in soil systems, reducing their leachability and absorption by plants.8
The building of topsoil by Mother Nature is a centuries long process. Adding compost to soil will help to quickly restore fertility that might otherwise take nature hundreds of years to replace. We humans deplete our soils in relatively short periods of time. By composting our organic refuse and returning it to the land, we can restore that fertility in relatively short periods of time.
Fertile soil yields better food, thereby promoting good health. The Hunzas of northern India have been studied to a great extent. Sir Albert Howard reported, “When the health and physique of the various northern Indian races were studied in detail, the best were those of the Hunzas, a hardy, agile, and vigorous people living in one of the high mountain valleys of the Gilgit Agency . . . There is little or no difference between the kinds of food eaten by these hillmen and by the rest of northern India. There is, however, a great difference in the way these foods are grown . . . [T]he very greatest care is taken to return to the soil all human, animal and vegetable [refuse] after being first composted together. Land is limited: upon the way it is looked after, life depends.” 9
GOMER THE PILE
There are several reasons for piling composting material. A pile keeps the material from drying out or cooling down premature- ly. A high level of moisture (50-60%) is necessary for the microorganisms to work happily.10 A pile prevents leaching and waterlogging, and holds heat. Vertical walls around a pile, especially if they’re made of wood or bales of straw, keep the wind off and will prevent one side of the pile (the windward side) from cooling down prematurely.
A neat, contained pile looks better. It looks like you know what you’re doing when making compost, instead of looking like a garbage dump. A constructed compost bin also helps to keep out nuisance animals such as dogs.
A pile makes it easier to layer or cover the compost. When a smelly deposit is added to the top of the pile, it’s essential to cover it with clean organic material to eliminate unpleasant odors and to help trap necessary oxygen in the pile. Therefore, if you’re going to make compost, don’t just fling it out in your yard in a heap. Construct a nice bin and do it right. That bin doesn’t have to cost money; it can be made from recycled wood or cement blocks. Wood may be preferable as it will insulate the pile and prevent heat loss and frost penetration. Avoid woods that have been soaked in toxic chemicals.
A backyard composting system doesn’t have to be complicated in any way. It doesn’t require electricity, technology, gimmicks or doodads. You don’t need shredders, choppers, grinders or any machines whatsoever.
FOUR NECESSITIES FOR GOOD COMPOST
Compost must be kept moist. A dry pile will not work — it will just sit there and look bored. It’s amazing how much moisture an active compost pile can absorb. When people who don’t have any experience with compost try to picture a humanure compost pile in someone’s backyard, they imagine a giant, fly-infested, smelly heap of excrement, draining all manner of noxious, stinky liquids out of the bottom of the compost pile. However, a compost pile is not a pile of garbage or waste. Thanks to the miracle of composting, the pile becomes a living, breathing, biological mass, an organic sponge that absorbs quite a bit of moisture. The pile is not likely to create a leaching problem unless subjected to sustained heavy rains — then it can simply be covered.
Why do compost piles require moisture? For one thing, com- post loses a lot of moisture into the air during the composting process, which commonly causes a compost pile to shrink 40-80%11. Even when wet materials are composted, a pile can undergo considerable drying.12 An initial moisture content of 65% can dwindle down to 20 to 30% in only a week, according to some researchers.13 It is more likely that one will have to add moisture to one’s compost than have to deal with excess moisture leaching from it.
The amount of moisture a compost pile receives or needs depends on the materials put into the pile as well as the location of the pile. In Pennsylvania, there are about 36 inches (one meter) of rainfall each year. Compost piles rarely need watering under these conditions. According to Sir Albert Howard, watering a compost pile in an area of England where the annual rainfall is 24 inches is also unnecessary. Nevertheless, the water required for compost-making may be around 200 to 300 gallons for each cubic yard of finished com- post.14 This moisture requirement will be met when human urine is used in humanure compost and the top of the pile is uncovered and receiving adequate rainfall. Additional water can come from moist organic materials such as food scraps. If adequate rainfall is not avail- able and the contents of the pile are not moist, watering will be necessary to produce a moisture content equivalent to a squeezed-out sponge. Graywater from household drains or collected rainwater would suffice for this purpose.
Compost requires the cultivation of aerobic, or oxygen loving, bacteria in order to ensure thermophilic decomposition. This is done by adding bulky materials to the compost pile in order to create tiny interstitial air spaces. Aerobic bacteria will suffer from a lack of oxygen if drowned in liquid.
Bacterial decomposition can also take place anaerobically, but this is a slower, cooler process which can, quite frankly, stink. Anaerobic odors can smell like rotten eggs (caused by hydrogen sulfide), sour milk (caused by butyric acids), vinegar (acetic acids), vomit (valeic acids), and putrification (alcohols and phenolic com- pounds).15 Obviously, we want to avoid such odors by maintaining an aerobic compost pile.
Good, healthy, aerobic compost need not offend one’s sense of smell. However, in order for this to be true, a simple rule must be fol- lowed: anything added to a compost pile that smells bad must be covered with a clean, organic, non-smelly material. If you’re using a compost toilet, then you must cover the deposits in your toilet after each use. You must likewise cover your compost pile each time you add material to it. Good compost toilet cover materials include sawdust, peat moss, leaves, rice hulls, coco coir and lots of other things. Good cover mate- rials for a compost pile include weeds, straw, hay, leaves and other bulky material which will help trap oxygen in the compost. Adequately covering compost with a clean organic material is the simple secret to odor prevention. It also keeps flies off the compost.
Dehydration will cause the compost microorganisms to stop working. So will freezing. Compost piles will not work if frozen.
However, the microorganisms can simply wait until the temperature rises enough for them to thaw out and then they’ll work feverishly. If you have room, you can continue to add material to a frozen compost pile. After a thaw, the pile should work up a steam as if nothing happened.
4) BALANCED DIET
A good blend of materials (a good carbon/nitrogen balance in compost lingo) is required for a nice, hot compost pile. Since most of the materials commonly added to a backyard compost pile are high in carbon, a source of nitrogen must be incorporated into the blend of ingredients. This isn’t as difficult as it may seem. You can carry bundles of weeds to your compost pile, add hay, straw, leaves and food scraps, but you may still be short on nitrogen. Of course the solution is simple — add manure. Where can you get manure? From an animal. Where can you find an animal? Look in a mirror.
Rodale states in The Complete Book of Composting that the average gardener may have difficulty in obtaining manure for the compost heap, but with “a little ingenuity and a thorough search,” it can be found. A gardener in the book testifies that when he gets “all steamed up to build myself a good compost pile, there has always been one big question that sits and thumbs its nose at me: Where am I going to find the manure? I am willing to bet, too, that the lack of manure is one of the reasons why your compost pile is not the thriving humus factory that it might be.”
Hmmm. Where can a large animal like a human being find manure? Gee, that’s a tough one. Let’s think real hard about that. Perhaps with a little “ingenuity and a thorough search” we can come up with a source. Where is that mirror, anyway? Might be a clue there.
More to come on carbon/nitrogen ratios, composting, and the world of humanure!
Written By: Joe Jenkins