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Rethinking big: A waterless sewage system in the urban areas

Image credit: https://www.pexels.com/photo/recycling-of-water-on-sewage-treatment-plant-4742023/

jnikola Nov 09, 2021
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We can see Elon Musk and Jeff Bezos investing a lot of money in clean energy, fast travels, space travels, free internet, ..., but what's with some of the fundamentally wrong ideas?
There is one thing I am really concerned about and that's the sewage system and how it works (at least in my city). As shown in the picture below, most often we can see the combined sewage system. It collects sewage from your apartment and mixes it with rain.
Figure 1. A combined sewers
I see two big problems:
  1. The crazy amounts of drinkable water used for washing away our feces
  2. All this feces ending up in the rivers and seas
I know there are expensive filters and norms to achieve when we talk about throwing away feces in the rivers, but it would all be unnecessaryif we had a different system. Besides, all the drinkable water washing away our feces could be used for drinking in the dry parts of the world.

  • Can you think of a waterless sewage system, its component, advancement of the existing solutions, etc., that could work?
  • How would you make the feces recyclable on a large scale?
  • Is there a way how we can live clean without the use of water like mentioned above?


Creative contributions

A toilet that turns feces into dry pellet

jnikola Nov 09, 2021
The idea is to create a toilet that automatically dries the feces and creates a dry pellet out of it. The pellet can be thrown away in special containers and picked up by the managing company. The company could, after the analysis and processing, sell dry pellets as a fertilizer for your agricultural field or shipped to the desert and mix them with sand to support the growth of vegetation.
The concept:
The toilet should somehow dry the pellet, isolate or remove the smell, store it in a container that can be sealed and thrown away.
The benefits:
  • handling feces as a type of waste
  • creating a new prosperous market
  • creating a space for start-up companies to find innovative solutions on how to manage the pellet
  • no in-wall or underground sewage pipelines needed while constructing a building or a city
  • no smell
  • less water usage
  • less water contamination
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Shireesh Apte
Shireesh Apte2 years ago
How about an alteration of intestinal microbiota content so as to increase digestibility of ingested food (decrease the fecal mass) ? Less feces translates to lesser volume of water used in flushing. More research is needed in humans in this regard.

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jnikola2 years ago
Shireesh Apte Okay, great find and a great idea. I am interested in hearing where this would lead us. Would you like to do some research on it and write an idea/challenge, or should I?
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Shireesh Apte
Shireesh Apte2 years ago
J. Nikola Feel free to continue along this train of thought.
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What about the urine and a variety of other stuff that ends up in the sewers?

Povilas S
Povilas S Nov 12, 2021
Are feces really the only/main problem? Even urine still needs to be flushed with water and what's way worse is that people throw a variety of stuff in their toilets from unused food to tampons, condoms, cigarettes, etc. They should be then somehow strictly discouraged from doing the latter.
Urine could be diluted with water and used in the garden as a sort of fertilizer, but you'd need a lot of water to dilute it to the right urea concentration that won't harm the plants and in general, it's controversial whether it's good or not to use it for this. Then there should be a separate system for urine collection developed as well as separate one for feces. Urine waste system would need to use water, either way, be it for flushing or diluting. There are waterless urinals, they are considered very eco-friendly for not using any water, but they use chemicals to block the smell of the collected urine and I'm not sure where all the urine is discarded afterwards, perhaps flushed down to the sewage.
All that said I think you touched an important problem here which definitely needs some innovations/alternative solutions.
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jnikola3 years ago
Fair questions. Urine should be dried up along with feces. I wouldn't flush it. Maybe a sort of a liquid chemical could be used to neutralize the smell and to help feces disintegrate. Then, during the drying process, the chemical could turn into a gel or a mass binding all together and helping the further processing.
Concerning tampons, condoms, cigarettes, etc., I think we have a big problem of people being lazy to throw it in the garbage. It can cause the obstruction of sewage pipes and nasty floods in the bathroom. If we switch to dry systems, the same kind of "malfunction" or "damage" should occur if someone throws tampons, condoms, or anything that reduced the effectiveness of the drying process. I think that's the only way how people learn - by paying for their errors and laziness.
Using the urine as a fertilizer could work, but as you mentioned, in a very diluted form and only with the plants that need acid soil to grow. But I assume the dried pellet (the product of the waterless toilet), could be used for the same purpose. Of course, it should be primarily tested for its safety of use in the garden and processed, as needed.
I will check the waterless urinals you mentioned, they could be an interesting source of new ideas!
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