Let’s recollect an all too familiar experience for most of us in the so called “developed” world.
You are sitting at your desk, browsing your computer. Suddently, that familiar feeling comes, distracting you from your work or your entertainment. You ignore it, at first, since there are more important things that require your attention. But the urge keeps on increasing, slowly, over time. Suddenly, it’s the only thing on your mind. You head to the bathroom and release a golden stream in your toilet. After you’re done cleaning, you press the magical button and you never have to think about it again.
Most people never bother to think about something as yucky as urine, since we have all been taught to just dispose of it in the appropriate places and ignore it. But the truth is that we are part of an ecosystem, and our outputs are part of an intricate web that connects trophic levels of organisms with soil, water and air resources. For this ecosystem, our urine is valuable and will be processed to feed other organisms in other levels, recycling the nutrients until they reach us again.
But in our cities, we have constructed a slightly different reality. Once we flush our urine down the toilet, we immediately dilute it with freshwater, a precious resource. Our urine will meet other wastewater streams which will contain feces and other fluids until it reaches a wastewater treatment plant. If your city has a combined sewer system (which means the stormwater runoff from rains is mixed with wastewater in the pipes), then your urine will be diluted even further.
Depending on the wastewater treatment plant capacity and technology, the sewage might just suffer a light treatment to meet municipal standards for discharge in a nearby stream, river, lake or ocean. Alternatively, the sewage might suffer further biological degradation and filtration to meet stricter standards. By-products of a wastewater treatment plant include sludge and treated water. The treated water is returned to the ecosystem, whereas sludge may be dried and used for compost and agricultural practices or digested and used for energy production.
Sounds like a good deal overall, right?
Nonetheless, most of us who study wastewater engineering know how expensive and energy intensive these processes can be. On top of that, many of these wastewater treatment plants provide a single point of failure network, making them particularly vulnerable to a sudden power failure, machine malfunction or overwhelming influent. The reason why conventional wastewater treatment is so expensive and energy intensive is due to the fact that some of the main processes’ goal is to separate solids and nutrients from the water, something that could have been easily prevented in the start of our urine journey!
This is why dry/composting toilets or separating toilets have been the topic of research over recent years, since they can supply a solution to the dillution issue, and they keep urine and feces separated for their potential different uses. On the other hand, they are limited in the user benefit they provide, since composting for example takes a considerable amount of time and “only” produces soil as a by-product.
However, most people are not interested in taking care of their waste simply out of the goodness of their hearts or because of environmental awareness, especially considering how unpleasant the smell can be. Even composting might take at best 3 months until you have an useful by-product, and might require too much space to handle daily waste flows.
Anthroponics may be able to provide a more viable alternative since it is a decentralized system which provides the user with a direct benefit: a crop which the user can consume, sell as a fresh produce or process into a product and sell. Anthroponics can be a sustainable way to grow food and fish, without the use of fossil-fuel based industrial fertilizers, while at the same time treating wastewater.
As anthroponic systems are pioneered and explored, their limitations will become clear. But for now, they warrant enough curiosity so that we can think and imagine how we can incorporate them in our apartments and households so we can create more resilient and sustainable agricultural production systems and wastewater treatment systems.