Would you believe me if I told you we are flushing our most valuable resources down the toilet?
It’s simple: we eat, therefore we poop. And though we think of and treat this excrement as waste, it is full of the same nutrients we pump into our diets. Poop has in it water, potassium, phosphorous and nitrogen. Also included are thousands of beneficial bacteria that live to eat and decompose our waste. When given the opportunity to decompose naturally, our poop turns into soil that is healthier than what you can buy at a local nursery.
It just so happens that water, potassium, phosphorous and nitrogen are essential nutrients needed to grow food. Farms use tons of energy-intensive synthetic fertilizers to feed their crops, when instead they could use soil created from nutrient-rich human waste, also known as “humanure”.
It’s not only essential nutrients we flush each time we go to the bathroom. Even the most efficient toilets flush 1.5 liters of potable tap water down the toilet. For those of us in Alameda County, that is 1.5 liters of pure snowmelt from the Hetch Hetchy Reservoir.
Yep. We poop in water we could drink!
So, where does this contaminated water go after we flush it down the toilet? Most toilets in developed areas are hooked up to sewage lines. To clean the water you pooped in, sewage treatment plants pump chlorine and other toxic chemicals into the wastewater. After multiple disinfection and de-chlorination steps (because chlorine is, believe it or not, poisonous for our environment), the water and contaminated sludge are pumped into rivers, deltas, lakes or ground water. In the bestcase scenarios, the treated wastewater and sludge are used in agriculture after further disinfection and after synthetic nutrients are added, where the toxic chemicals still manage to pollute the environment. At worst, sludge is dumped directly into our waterways. Now that’s a waste!
But it’s not only water and nutrients we are wasting. The U.S. spends $4 billion annually to produce the energy needed to power centralized sewage treatment plants. That’s three percent of our total energy budget.
Would you believe me if I told you we can safely and sanitarily capture nutrients in humanure without contaminating water or spending billions of dollars?
Composting toilets look like flush toilets, but instead of flushing excrement down pipes, a ventilated container collects it. Biodegradation set in motion by our thousands of natural body bacteria then generates enough heat to kill harmful pathogens and viruses as well as evaporate 70 to 90 percent of the original mass.
Worried about smell? Just add carbon-rich material (shredded paper or sawdust) after each use, and be sure that oxygen circulates through vents in the container. Amazingly, carbon and oxygen produce an odor-free composting toilet!
As it fills, the container must be emptied onto a compost pile where it decomposes for a few more months, after which it is ready to be incorporated onto gardens or farms.
In place of clean water, energy, and tax dollars, a small amount of labor on the side of the homeowner can make functioning composting toilets a safe, viable alternative to our current wasteful, toxic and expensive human waste management processes.
Benefits of composting toilets are being realized around the world. In lieu of a nonexistent sewage infrastructure, developing regions create composting toilets to save money and fertilize crops. But even more developed countries — Sweden, for example — have implemented composting toilets in homes for decades to reduce water use and rebuild soils. New Zealanders have constructed largescale composting toilets in commercial buildings that generate soil and nutrients to grow enough food for the people who work in those buildings.
State laws require habitable buildings to have flush toilets and say that human waste can’t be transported across property lines without a license. Waste management officials, city planners and public health authorities in the U.S. still have much to learn about the use of composting toilet systems in urban areas in order for us to take full advantage of our poop.
It’s time American cities work with state and federal public health officials to create more homeowner-friendly composting toilet regulations that encourage people to make better use of our poop and our water resources. Our soils, waterways, and budgets depend on it!
Gwendolyn von Klan studies geography and sustainable urban planning at UC Berkeley.