Sustainable Stool Part 1

Written by Sarah Steely

Tuesday, January 22nd 2008

This is the first in a three part series about human manure and its potential use as a sustainable alternative to conventional sewage treatment.

Society frowns on the reuse of our excrement. It is viewed as waste and so we treat it as such: we dispose of it in landfills, in oceans or other bodies of water, or even in simple pits. But human manure is rich in nutrients, especially nitrogen and phosphorus, both of which are vital for plant growth. Human manure, or humanure as some people call it, is a great way to recycle nutrients we have consumed and put them back into the soil. It is a non-polluting way to dispose of our everyday organic waste that, if composted correctly, is free of human pathogens and other disease causing organisms. Like any compost, it makes a good fertilizer.

There are many benefits of compost. It enriches soil by adding organic material and nutrients vital to plant growth. It can increase water retention, introduce beneficial microorganisms and earthworms, reduces the amount of organic material in landfills, thereby reducing methane emissions, and save money by producing food (Jenkins 1999). Twenty-five percent of the planet’s surface is used to produce food, which is staggering when one remembers that conventional farming involves monocropping and the application of pesticides, herbicides, and chemical fertilizers. Pesticides and herbicides that are outlawed in developed nations still have a market in other countries. The insecticide monocrotophos, which is highly toxic to the neurological system and was banned in the US in 1988, is one of India’s top-selling pesticides (Worldwatch Institute 2004). Additionally, chemical fertilizer use is the primary non-point source of nitrogen and phosphorus pollution (Puckett 1995). It is evident that there are many advantages to using compost on crops—now what if that compost was derived from our own personal wastes?
sewage treatment plant

The application of raw sewage to crops is a no-no since many pathogens and parasitic worms can be transmitted through fecal matter and urine, but with proper thermophilic composting they are killed off and the excrement is converted to organic matter that works well in the garden. What better way to practice sustainability than to recycle our excrement via composting and apply it to the soil? It is an unbroken circle from crop, to harvest, to consumption, to toilet, to compost, to soil, to crop, to harvest...you get the point.

Conventional methods of sewage treatment in developed nations involve at least a primary treatment system, but usually a secondary and even a tertiary treatment as well. During the process, the sludge and water are separated. The water is treated and released into rivers, lakes, oceans, and other bodies of water where the treated water is diluted and carried away. This water usually contains higher than average levels of nitrates and chlorine, as well as any other chemicals and pharmaceuticals that resisted degradation during the treatment process.

There are limited options of disposal for sewage sludge. Raw sewage and sludge used to be dumped into the oceans, but that is now illegal. Today, most sludge is dehydrated and buried in a landfill. Some treatment facilities compost the sludge where it is then used in agriculture. Consider this: In 2000, approximately 1.1 billion people lacked access to safe drinking water while 2 out of every 5 people did not have adequate sanitation facilities, such as a sewer, septic tank, or pit latrine. (Worldwatch Institute 2004) That is quite a lot of raw sewage floating around, considering we have over 7 billion people on the planet.

In a world where natural resources are dwindling and where the “225 richest people in the world (about .000003% of the world’s population) have as much acquired wealth as the poorest half of the entire human race (Jenkins 1999)”, people are beginning to look to other alternatives. In 2002, the global sales of certified organic foods was an estimated $23 billion dollars while an estimated 23 million hectares are farmed yearly as certified organic (this is not even considering organic food that is not “certified”). With focus turning on organic agriculture and sustainable practices, it is a little perplexing why so many still reject the idea of human excrement composting.

Part of the problem is that we are raised and conditioned to think of our feces as waste and that no sane, hygienic person would have anything to do with it once it exits via the anal sphincter. If we could just get over that attitude as a society, ah, the possibilities…but back to reality. It is quite simple and cheap for families to construct a compost pile and toilet system. Maintenance of the compost pile is required and essential to ensure that it heats up and that pathogens are killed, so this is not a task for an unmotivated, apathetic individual. But the work is not that intensive (just repetitive) and the rewards for it pay back in excess. Composting of our excrement has great potential as a sustainable use of one of the most common human waste products.

Part 2

Works Consulted

Jenkins, Joseph. 1999. The Humanure Handbook; A Guide To Composting Human Manure. Chelsea Green Publishing, VT.

Puckett, Larry J. 1995. “Identifying the Major Sources of Nutrient Water Pollution.” Environmental Science and Technology. 29:9. 408A-414A.

Worldwatch Institute. 2004. State of the World 2004. W.W. Norton & Company, New York, NY.

Last update: April 28, 2008
08:08 am

Published in : Research, Eco Culture