Permaculture allows nature to do its thing. The gardens are lush and beautiful. While the birds chirp high in the trees, soft aromas mix in the air as a butterflies pollinate the flowers. Animals and plants coexist in natural harmony while humans organize and revel in their creation. It is a world rich with chemistry and beauty. This article hardly mentions any of that. This article focuses on the…well… less glorious aspects of nature; waste. Yes. Poop. Ever wonder why it burns so well? One word – methane. One of the most devastating greenhouse gases is methane. Natural gas is ninety-five per cent methane. Methane (CH4) reacts with atmospheric oxygen (O2) when burnt, resulting in carbon dioxide (CO2) and water vapor (H2O), which are far less harmful to the environment. This is why we should stop flushing a major energy source down the toilet and stop whining. Everyone poops, its time to get used to using it.
To begin, it is important to understand what methane is and where it comes from. The short answer is anaerobic bacteria, which by definition operates without the presence of oxygen. It is estimated that over fifty percent of the atmospheric methane is directly caused by human activity. This information begs the question – if humans activity creates so much methane, and natural gas is methane, then how can we not renew our supply of natural gas? Well, actually, we can. With poop.
Like I said, everybody poops. That’s a fact. Normally, that waste gets flushed into some distant sewage treatment facility to be sterilized and disposed of. Everyone also eats, and many cook by burning natural (methane) gas. All that waste, when exposed to anaerobic conditions, will be broken down by bacteria that release methane gas as a by-product. By now, there has been a lot of exposure of a food industry that forces animals to stand in their own waste throughout their entire lives. Disgusting, but besides the point. This waste produces methane, which is freely released into the atmosphere. Imagine for one moment that all of that excrement was thrown into an airtight hole in the ground with an expanding balloon to capture the gaseous by-products (methane). Stop imagining. The technology does exist. It’s called a biodigester. Using a biodigester, all organic waste becomes a valuable commodity in the form of natural gas. Of course, some sludgy goop is left over, but if allowed enough time, it will become and odorless mass that can be used as a plant fertilizer. Everything gets used. Natural gas is produced. Waste is disposed of. Though CO2 is still a greenhouse gas, it is much less so than methane and can be directly converted to oxygen by plants in the area. If the process sounds complicated, it’s not.
Biodigesters are so cheap and easy that they have been implemented in many developing and developed nations such as Vietnam, Kenya, China, India, Thailand, the Philippines, Nepal and Brazil, amongst others. Oftentimes these projects use cheap, airtight plastic and a simple two chamber system, though these often break down after about five years. With a little more resources, however, a more permanent structure can be built that will last much longer. Little maintenance is required and the system is odorless. Typically, biodigesters only produce up to four hours of natural gas per household per day, so the system is not perfect, but it is a step in the right direction. More complex, three chamber systems can be made and are far more efficient than the two chamber counterparts. One other disadvantage is that the anaerobic bacteria only functions above approximately sixty degrees fahrenheit and is most efficient at ninety five degrees (this is highly strain dependant, though generally higher temperatures are better). Despite the few drawbacks, however, biodigesters are natural, use no energy, produce clean gas, fertilizer, and can be integrates into an already existing gas and sewage system.
The processes that occur within the biodigester are the exact same as those that occur in the human digestive tract. Anaerobic decomposition occurs in four primary stages called hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Decomposition is done by acid forming bacteria known as acetogens, and by methane forming bacteria called methanogens. Hydrolysis breaks down large, complex carbohydrate, fat and protein molecules into sugar, fatty acids and amino acids respectively. During acidogenesis, these molecules are broken down once more into carbonic acids and alcohol as well as hydrogen (H2), carbon dioxide (CO2) and ammonia (NH3). In the next stage, molecules are reduced to acetic acids (C2H4O2), hydrogen, and carbon dioxide. In the final stage, methanogens complete the process to produce methane and carbon dioxide. Acetogens are generally more present in the beginning stages, whereas methanogens occur later, though they are both present at every stage. Everything besides carbon, oxygen, and hydrogen atoms are left in the residual sludge, including macro and micro nutrients. Biodigesters work best when separate chambers for each stage are used, but this is not necessary. This results in perfectly balanced, odorless fertilizer that must be removed periodically for optimal efficiency. Best of all, reactions cause such hot and acidic environments that pathogens like e. coli or cholera are destroyed.
Though technical, this process occurs naturally both inside living organisms and in their surrounding environment. A biodigester merely concentrates all the waste that needs to be broken down so that is usable to plants as quickly as possible while making natural gas available for human use. Biodigesters are highly relevant in permaculture because they close the loop between waste and nutrients, thus improving efficiency and reducing waste. The technology is far from perfect, with issues in cost, replacement parts availability, and social acceptance, but through further implementation these problems can be overcome. In a permaculture garden, any organic waste can be processed in the biodigester, including meat and dairy that is not suitable for compost. For information biodigesters, consult any of these three websites, though many more exist. Instead of reducing waste, let’s stop thinking about it as waste and start reusing everything. I mean everything. Even poop.