Flushing Toilets

The age old problem of what to do and where to put human excreta is alive and kicking. People have dealt with it various ways over the years.

The earliest known sewage systems dating to c. 2600BCE, are those of the Indus people in Mohenjo-daro and Harappa in modern day Pakistan. Waste from toilets in houses flowed into brick drains, street side channels and into soak pits.

The Minoans in Crete had sophisticated drainage systems from around c. 2500. The Palace of Knossos had flushing systems in which the toilet was linked to a hole outside the toilet door by an under floor terracotta pipe. When it rained, the water from the roof would flush the loo, while in dry weather, it is likely an attendant would pour water into the hole and flush the waste through a system of stone built drains and terracotta pipes to a soak pit deep underground. Other Minoan palaces had similar systems.

The Romans were famous for their toilets but for them places like the River Tiber were handy exit points for waste disposal.

Today, much human excreta is processed in sewage plants, then dumped in the sea. Excreta from humans and animals that is washed from land into our seas, rivers and lakes contributes to water pollution. 

What to do?

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AI has come up with the following:

Society could adopt several less polluting methods for handling human excreta:

  • Anaerobic digestion: Waste is processed in sealed digesters to produce biogas for energy and nutrient-rich slurry for fertiliser.
  • Urine diversion: Separating urine, which contains most nutrients, allows for nutrient recovery and reduces treatment loads.
  • Constructed wetlands: Natural reed bed systems filter and break down waste with minimal energy input.
  • Blackwater recycling: Closed-loop systems treat waste locally for reuse in irrigation or toilet flushing, avoiding discharge to the sea.
  • Composting toilets: Dry or waterless toilets convert waste into compost via controlled aerobic decomposition, producing soil amendments instead of effluent.

Each method focuses on resource recovery and minimises environmental contamination compared to conventional sewage plants and marine outfalls.

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Could any of these AI suggestions realistically be implemented in all new homes, and eventually in all homes? Is the government likely to be thinking big on sewage matters?

The idea of anaerobic digestion producing biogas for energy sounds good, but would biogas have a bigger negative impact on the atmosphere than other methods?

Anybody got ideas for a better system than we currently have?

  • Whats in the wizso though, how does it cope with toilet paper, does it smell artificial?

    I ask because a lot of products that say they sort out one environmental problem actually cause another

  • I'm loving these drainage discussions! Around where I work, the ground doesn't drain well, so we often have to store water in ponds and permeable paving etc and release it slowly to a watercourse or sewer. That way you're reducing flood risk downstream because the water isn't rushing away off-site. That's done using a vortex flow control which is a pretty cool type of manhole

  • Hope that's interesting :) 

    That is very interesting and more - it’s fascinating.

    Perhaps new homes should have built in roof gardens and water butts. 

    I’ve read some of your link to sustainable drainage systems and it looks like a very attractive proposition. It’s similar in many ways to the soak pit system the Minoans used except SuDS use more sophisticated sequences of techniques with control over the water flow. 

    The permeable paving blocks look good but I’m wondering if their unevenness would make it more difficult to weed between the blocks, because that could put off people?

    People use a metal hook type implement or a special brush to destroy and remove the weeds between paving blocks or they use weed killer. 

    Thank you so much for answering the questions and taking time to answer. I’m looking forward to reading your link material properly later and find archaeological surveys of Minoan palaces to compare and contrast. 

  • Joy Well where does it go? Any imaginative suggestions welcome. Joy

  • I agree that they should be brought back into public ownership. There have been too many payouts and rewards (for what!). People deserve better.

  • I have read a number of articles about how the national grid is making it really hard to generate energy and share surplus with the grid now - long delays in getting connected and various regulations on what you can have, who can install it etc. 

    I know some people here in N. Ireland generate energy for the grid but its not something that is heavily promoted here.

    We have a different all Ireland system here so our prices aren’t subject to the same fluctuations.

  • This discussion reminds me of an episode of the Big Bang theory. Where Raj asks about toilets in Atlantis, which is supposed to be under the sea, "How do they flush toilets in Atlantis, where does the poo go?".

  • Good idea but a bit expensve. I tend to use a spray intended to reduce smells of solid waste and flush every 2nd or 3rd liquid 'go' - 7 sprays in the pan and it floats on top of the water.

  • I think flusing with pure water is really wasteful.

    We've been giving these a try recently - prompted, in part, by repeated local water shortages - and I think we'll carry on using them.

    The idea, as they put it, is to "Drop a Wizso into the loo after a pee", and save water by going longer between flushes. Obviously, we can delay flushing anyway, but this makes it less unpleasant (for me, at least), from a sensory perspective:

    Wizso.com

  • I note that some states in the USA prohibit the collection of rainwater and will fine you for doing so: https://www.wikihow.com/Why-Is-Collecting-Rainwater-Illegal

    Given how the UK has copied so many American ways when it comes to generating money from environmental rules, I wonder if this is being considered here.

    I think it is ridiculous but this clearly is not enough to stop the jobsworths from creating these money making opportunities.

  • Do any European countries use the UK system of sharing drainage of fresh water and sewage?

    Great question. I didn't know so I went looking. 

    Most of Europe has Combined Sewer systems (CS) in some population centres largely constructed before the 21st centuary https://www.sciencedirect.com/science/article/pii/S2214581822000933 and I've found some other references  to some areas in the USA and Australia where Combined Sewer Overflows also occur, but it's much less common (partly because a lot of the infrastructure is considerably more recent). That's the combination of surface freshwater and sewage. There are some efforts to fix this with for example some german cities working on separating stormwater and sewage, like with the attempt in london. 

    In terms of separation of grey water and sewage there are a few case studies, but none in high density population centres as of yet that I know of. 

    Why do some areas in other European countries ask people to dispose of used toilet paper in bins rather than in the toilet bowl? Are there two separate systems in the one country?

    This is historic. A lot of old sewage pipes in places like Greece have very small diameters and toilet paper poses a blockage risk. It sometimes varies building to building. They still generally have combined sewage systems in the cities as a whole particularly in older city areas. 

    What is the most effective way of preventing water runoff from roads or would a combination of things be best? E.g, verge side planting?

    There are many many many many many options for this and many people who study it. Combinations depending on the setting works best. Options I personally really love: anything that increases flow to groundwater (actually there are settings where this would be bad or just not work, but mostly I love this)

    So sustainable drainage systems https://www.bgs.ac.uk/geology-projects/suds/ work through a number of factors:

    Collecting or preventing runoff hitting the street: collecting water from roof drainage for future use (see water butts for irrigation), green roofs (plants on top so they take up a lot of extra water)

    Collection areas such as ponds and wetlands (also good for wildlife, and if done correctly can also be used for plant based pollution removal (vehicles drop so much pollutants onto the road)

    Areas that increase infiltration (flow to groundwater) like soakaways. Some road material design can also do a lot here. Porous asphalt has a lot going for it https://www.sciencedirect.com/topics/engineering/porous-asphalt with its ability to let water soak straight through rather than having to drain or pool at all. Coarse gravel based road sides can also be really good. This can have aquifer pollutant implications so you want to be careful about a) what is travelling along the road and b) whether the aquifer will be able to handle those pollutants (rock type, conductivity and proximity to boreholes or springs are important here) 

    Basically, you want to reduce the amount of impervious or low permeability materials you're using in drainage. This has additional benefits in terms of overall flooding quite a lot of the time too. 

    Hope that's interesting :) 

  • Like so many things, the national grid is aging and in need of updating. Also successive governments have made promises to support green energy large and small, the public took up the idea of solar panels in great numbers, feeling they could do thier own small part in saving the planet, the government ended up paying "to much" in feed in tariff, so they cut them.

    Our utilities are a mess, they may not have been in the best state before privatisation, but I'm not sure anyone could say that privatisation has been great, we still have underinvestment, high prices and massive payouts to share holders and most of the owners of our utilities are foreign. I think bringing them back into public ownership should be a matter of national security.

  • Actually, now I’m starting to wonder if you envisaged toilets (as in the modern ceramic toilet bowl and cistern) being flushed by something bigger, like a giant toilet? Blush

  • I can be quite a simple being at times! 

  • Sweat smile The title was misleading.

    I was thinking of it more in the broader sense as toilets that flush, i.e., a hole/pit/piece of land in which people poo/pee or in which an attendant empties a pee/poo bucket, and water (including rain) disperses it into an area away from the original pee/poo spot.

    For me, the modern ceramic toilet bowl came second, although I do regularly use one. 

  • I thought this was actually going to be about flushing toilets! 

  • The utility sector current model of funding and pricing is not working very well. It’s part of the reason why our heating oil, petrol and diesel prices have increased faster and fluctuate more than they do in the US. 

  • Maybe greater financial benefits for people who produce their own energy and have less waste would incentivise people. 

    I have read a number of articles about how the national grid is making it really hard to generate energy and share surplus with the grid now - long delays in getting connected and various regulations on what you can have, who can install it etc. 

    I recall reading social media posts saying the the government have been dropping the price they pay as well or other irregularities but this is only social media so I don't know how reliable these reports are.

    Lastly, there is an abundance of generating capacity within the national grid but the government are paying companies NOT to generate electricity and thus lower the cost to consumers:

    https://www.bbc.com/news/articles/cdedjnw8e85o

    It isn't that the country needs the small producers, just that the big producers seem to be in cahoots with the government to get handouts and the consumers pay the cost.

    I doubt that the waste water system is any less corrupt unfortunately so the good ideas will probably be sidelined in order to keep paying the water companies at the taxpayers expense.

  • Maybe greater financial benefits for people who produce their own energy and have less waste would incentivise people. 

    i would like to know if urine could be utilised in a bathroom cleaner with green credentials.

  • I've heard how sewage works' waste is turned into slurry, given free to farmers, but this can lead to toxicity and micro-plastics being widely distributed, on the land and in rivers. Turning it in fertiliser seems a good solution - if these problems could be resolved, this could also be sold on to gardeners as commercial fertilisers are expensive, with the profit going back to the [hopefully] nationalized water companies

    It would be great if the issue of slurry toxicity could be resolved. It is such a great resource in some ways, but breathing the fumes is unpleasant and as you point out harmful. 

    I like the idea of microbes eating plastic. I have begun using garden lawn products with bacteria that eats grass thatch and goes on to enrich the soil. It’s not the same thing but it does help the surface water seep into the earth.

    NASA are looking into recycling astronauts' waste into food - but again, this might be repugnant for most. It perhaps could be turned into animal feed because they are not fussy eaters!

    Faeces washed down with a nice glass of white/yellow is not my idea of a good meal.Joy Seriously, anything that helps is needed.