Flushing Toilets

I work with water and these work very well and are used frequently in small scale off the grid areas, but are difficult to scale up due to the housing infrastructure we currently have and also simply a matter of space.

Sewage works do use anaerobic and aerobic decomposition, along with sediment collection (which later gets used for fertiliser). The treated effluent actually has very few harmful pathogens and these are easily diluted at the discharge points (most water treatment, including really nasty stuff like landfill leachate, is, at the end of the day, mostly dilution). This works great apart from as BeaE says, when surface water entering the same system, and this is becoming increasingly worse as both the sewage being delivered to sewage works (increases in housing in previously sparse areas), and the number of intense storms or heavy rainfall periods (climate change) increase. It is this that leads to most episodes of untreated effluent being discharged.

The problem with all of the ideas that AI has come up with is that it requires both completely separate waste systems for greywater and blackwater (talk to anyone who's had any pipework fixed in their house and imagine how putting that piping in would go) and either a location for executing this on or near the property (which both requires more space and is smellier than you think) or transport from many houses to a set location which would involve redoing all of the sewage lines, which is also way more than you think. Basically every road in the UK would need to be dug up. It's a massive challenge. This is absolutely not a country with infinite space.

In terms of adding it to new homes, you are counting on developers to pay for it. More difficult than you'd think. Then there is the question of who would manage the maintenance and disposal/use of the eventual waste products. Would it be taken on by the water companies and paid for by the house owners or a new type of company? What would happen if that company went under?

I think the biggest task right now is getting the sewerage separated from road drainage (and improving road drainage while we're at it, our drain system is not designed for these more intense rainstorm style weather patterns, climate change is very much a thing)

Eventually world wide we will need to look at reducing our water use (I mainly work with the sourcing of freshwater to drink, it's more of a problem than you'd think, even in this country, especially as we're getting more periods of drought, I refer you once again to climate change). A really good technique to build into new builds is the recycling of greywater to be used for things like flushing toilets. This reduces total waste water and preserves super high quality drinking water for the actual drinking bit. You may be able to drink from a toilet bowl, but you do not need to. 

Overall: 

Nice ideas, much harder to implement with limited space and an enormous undertaking for integration into existing infrastructure

It is absolutely essential to review how we're using freshwater and disposing of various different types of surface water

The current sewage treatment already does aerobic and anaerobic digestion very effectively, the issue is that they're largely at or over capacity so are struggling to process it all

Removal of surface runoff from this system will help with the point above and is probably the biggest priority and easiest to tackle currently. If done correctly, it will also help tackle flooding

All of these problems are being made worse by anthropogenic climate change. They will continue to be made worse by anthropogenic climate change. Limiting global warming worldwide will limit how much worse they will be made. 

You may have hit on a special interest. 

Warning: any questions may be answered in great detail, but will be greatly appreciated 

Gosh, that’s fantastic Fibonacci! Thank you very much for your detailed reply.

As you might have guessed, I’m out of my depth when it comes to water (no pun intended) - at least regarding water flushing.

Maybe some of my next questions are unfair to ask you as they don’t relate directly to the UK, but I would like to know the following:

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

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?

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?

I think more education is needed around the issue of people over using fresh water. Many people in this country quip “there’s no shortage of water this year”, when we get heavy rain over a few days. I think people don’t understand why taps shouldn’t be left running unnecessarily. We don’t have water charges in N. Ireland.

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

Fibonacci Squid said:

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. 

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.

ArchaeC said:

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. 

ArchaeC said:

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. 

ArchaeC said:

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 :) 

ArchaeC said:

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. 

ArchaeC said:

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. 

ArchaeC said:

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 :) 

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

Fibonacci Squid said:

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. 

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.