In parts one and two, I explored the problems with our current toilets (and the systems that support them), and looked at off-grid toilet designs for better ideas. Ultimately, the composting toilet is the best available option because it’s the lowest impact in just about every way. That having been said, getting people to use them will be a challenge that we can’t just ignore.
A Dose of Realism About Better Alternatives
Composting our solid waste on a mass scale (especially in cities) would require several things that make it problematic for politicians and voters.
First off, people aren’t going to want to make a major change to what they’re doing. Toilets are very convenient, with nothing but a quick push of a handle to make one’s excrement someone else’s problem, and the government is definitely subsidizing the cost of every flush, so we aren’t paying the true costs. Composting toilets would usually require their users to take the waste out of their toilet once the bin gets full, and take it either to their own composter for a garden (if they happen to be suburbanites who like spending time on organic gardening) or take it to the curb and put it in a designated can that takes compostables. Some cities already have yard waste cans that would work great for this.
The latter option (having someone else compost it) is obviously going to be the most feasible (most people don’t or can’t garden, especially in apartments and other dense developments), but it would require new fleets of vehicles to haul the partially-composted waste away, a big open space to do the composting, and a supply chain from there to farmers.
Best Idea I Found: Keep Existing Sewers, But Don’t Build Any New Ones
It still seems unlikely that most established cities are going to make the switch to composting unless they’re short on water or enough people become aware of the big problems sewers cause. For that reason, we may be stuck with sewer systems in most of the developed world. Even in places where there are water shortages, people are just too attached to the crappy status quo to think it’s worth doing anything different, even if that means massive water projects would be needed.
Change should happen where it can, but there’s still hope for the future when it comes to alternatives to sewers. There’s a significant portion of the developing world that doesn’t have sewers yet. 80% of the current global sewer systems don’t treat the sewage at all, simply dumping it untreated back into the environment, but that means they have minimal sunk costs in water treatment, and could still potentially spend that money on alternatives like mass composting.
Well-meaning NGOs, banks, and governments spending money to assist the developing world need to look at ways to help the least developed countries avoid repeating our dumb mistakes. They’re in the enviable position of being able to completely skip the fossil fuel phase, and they might be able to skip sewers as well if officials in those places can learn that there are big downsides to sewers for their people and natural resources.
Improving Sewer Systems
Back to the developed world that’s addicted to sewers, it might be possible to at least improve sewer systems in places that refuse to quit using them.
The most important thing sewer plants can do is switch to renewable energy. Compared to other things like composting, treatment plants are wasteful, but it’s better to power these plants using renewable energy than it is to power them using fossil fuels. Wasted energy is better than wasted energy that pollutes.
Another thing some treatment plants are doing is using the stink to generate electricity. Gases, especially methane, can do great harm if released into the atmosphere. They’re a more potent climate change agent than carbon dioxide is. By capturing these gases, directing them down a pipe, and using them to turn a generator, some plants are powering all of their own operations and even providing power to nearby cities. This isn’t as good as renewable energy, but it’s better than just venting the gases of flaring them.
Composting is also possible at this stage, despite the wasted water and electricity that goes into these treatment processes. Burning sludge or throwing it in a landfill doesn’t return nutrients to soils, and we have to get those nutrients from somewhere else. Nitrates and other fertilizers use even more energy to produce, transport, and use, so avoiding that can definitely lower impacts.
There are also changes we can make at home to help improve these processes.
One popular one is to reduce or eliminate toilet paper usage. This usually requires the use of a bidet, which does use more water, but the water used in a bidet generally uses a lot less water than paper production does. On the other hand, paper production can get water from places where it’s plentiful and then deliver paper to places where water is scarce, so it might not be the best option if you live in the desert (where we really can’t keep using that water).
Low consumption toilets are also a good idea. If you pull less water into your home, less energy is used to move that water into your home. If you flush less water down your drain, less energy is needed to process that black water into something safer. Thus, water use is energy use, and contributes to your personal impacts just as much as any other energy use does.
Finally, we need to look at more creative uses for grey water in our homes. Grey water is the water that comes from your sinks, bathtubs, showers, dishwasher, and clothes washer. Because there’s generally no fecal matter in that water, it’s a lot safer to treat and even reuse as is, even on site. Many people divert their grey water to water gardens, keeping the contaminants from rainwater from getting into rivers and lakes. It’s also possible to use grey water again to flush your toilet, with the simplest setups consisting of a sink installed on top of the toilet.
Some Final Thoughts
As I mentioned earlier, making changes to our homes to reduce their energy consumption, or even to make them clean energy producers, is a great idea. Solar, batteries, EVs in the driveway, and better insulation all come together to make for the home of the future. But, if we miss the toilet while designing that better home, we’re missing out on huge opportunities to improve not only our homes, but our environment generally.
If you have the means and the time, it really makes sense to gain independence from a municipal sewer system. Composting toilets, a home composting operation for a home garden, grey water reuse (also in a garden, where possible), and similar measures can have a great impact when combined with water efficiency. Adding rainwater collection (where there’s sufficient rain) can then turn the whole household into an entity that’s actually energy independent and doesn’t pass off any of its waste to be dumped in the environment elsewhere.
Beyond the environmental, doing all of this to a home can help make it more resilient to future climate change impacts and help the family inside that means everything to us be safer in the event of disasters or shortages. Even if you’re not an environmentalist, that alone is a good reason to consider adding these better alternatives to your house.
Featured image: A municipal wastewater treatment plant. Image by Jennifer Sensiba.