Flushing loos using rainwater

Discussion in 'Eco Talk' started by Hemel, Dec 11, 2016.

  1. Joe95

    Joe95 Screwfix Select

    I haven't read any of the above so I apologize if what I say has already been said:oops:. What i will say can be adapted to your situation.

    I installed a system like this to collect the rainwater in a function hall. Rainwater is collected off a huge flat roof and it all flows into a tank in a back room. The tank is 150000 liters.
    There is an overflow on the tank using a soil pipe, as there is two incoming standard rainwater pipes. This means even if the tanks fill up there is no way of them overflowing.The rainwater pipes are filtered at the hoppers on the roof so any blockages do not fill the rainwater pipe. The filters are cleared by the window cleaner monthly.There is a UV light in the tank to kill any bacteria.

    The tank has a water pump on it to add pressure to the system. There is a three port valve wired to a relay which is connected to a water sensor in the bottom of the rainwater tank. The valve switches between mains incoming water and the tank in 22mm copper, when the rainwater tank empties. Both the incoming feeds from the rainwater tank and the mains supply have double check valves(non return valves) on them just before the three port valve. This is the automatic switching system that means the system will automatically change to mains feed if the tank is emptied. There is an override manual mains tee into the pipework after the three port valve(with a double check valve too) so the toilets can still be flushed if the pump or motorized valve was to fail.

    All the plumbing from this system is kept separate and runs to the toilets. The urinals and toilets are on electric sensing valves, which means no water is stored there, I.E no cisterns. This means all water is drawn straight from the back room tank. This saves space in the rooms so they were able to add more cubicles inside them.

    The local water board and council were heavily involved when checking that all the pipework was kept separate and labelled through the runs, so it could not be unintentionally connected to the incoming mains or where it could be used as portable water. There was additional scrutiny as the council would the away the bar license if there was tap at any point in the run, so lockable valves had to be used to drain the tank and pipework.

    It may seem a complicated and intelligent system, but was fairly straightforward to install and was much cheaper than it may sound.
    They estimate they save over £400 every year.
    It is still running problem free after three years so i must have done something right. :D
     
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  2. KIAB

    KIAB Super Member

    A very well planned system.[​IMG]

    They seldom go wrong.
     
    Joe95 likes this.
  3. nigel willson

    nigel willson Screwfix Select

    You may not be worried by bacteria and the like but other bodies will be , water authority for one if you contaminate the public water supply or could!!!!
     
    KIAB likes this.
  4. Joe95

    Joe95 Screwfix Select

    The pump and motorized valve would be the only things that are likely to go wrong.:)

    Eight weeks of work over Jan and Feb, there was a refurb going on as a new wooden dance floor, a rear extension for kegs and bar stock and a Biofuel boiler, which also saves massively on the alternative gas fired ones.
    I had to install the rainwater system and the bathrooms, so there was plenty of work!

    The change to a Biofuel heating system is still quite rare, and there is not too much information on the internet about it, and a specialist firm did the work. I am considering installing a Biofuel boiler in my own house when i do my extension.
    Shame it hasn't taken off really. Doesn't have the same regs scrutiny as gas would too, so a competent person could do the bulk of the work if not all.
     
    Last edited: Dec 11, 2016
    KIAB likes this.
  5. sospan

    sospan Screwfix Select

    I have about a 350,000 litre "tank", I created behind some retaining walls. It built out of SUDS crates wrapped in pond liners. It isn't connected up at the moment but intend to use it as an emergency supply and eventually for a swimming pool / pond system once I get round to it.

    Too much hassle to include rainwater / grey water into housing systems. I prefer to keep it as an emergency supply because it won't take much in this country to interrupt our reservoir system.
     
    Joe95 likes this.
  6. Joe95

    Joe95 Screwfix Select

    Oh, for the great British summer? :p:D
     
  7. sospan

    sospan Screwfix Select

    The heating system that I am putting is going to be a mix of solar, geo thermal from a bore hole, solid fuel and gas. There are a couple of huge heat stores being fitted to store the hot water for both central heating and taps.
     
    Joe95 likes this.
  8. sospan

    sospan Screwfix Select

    Live in Wales, we don't get summer :oops:. What I was going to do was make it sort of like a victorian dumbbell with two pool separated by a swimlane with a perspex cover like a large cloche. Either end have like a pool house where in the summer can take the sides off. Hopefully can get some solar gain - or at least friction heat from the wind :D
    upload_2016-12-11_19-31-32.png
     
    Joe95 likes this.
  9. Joe95

    Joe95 Screwfix Select

    This follows my 'idea' of how i was going to do it.
    I am thinking of a solid fuel/Biofuel boiler with a large heat store/buffer tank, which will manage hot water and heating. There is much more work required for both manual valves and motorized valves, as well as the fact i want to incorporate more zones. Currently upstairs and downstairs is zoned, but i would like to take the 2nd bathroom, loft showroom and downstairs toilet on another and the kitchen separate too, with UF heating. It is just me, the missues and our dog, so we do not need copious amounts of HW, but i have been told i will still save over a conventional system gas boiler.


    How are you going to integrate solar and geothermal into it?
     
  10. Hemel

    Hemel New Member

    Thanks Joe95 - I liked everything you said, (except the bit about the water board and council being involved) can you post details of the three port valves and the check valves please?

    On a related subject, I spent the first 30 years of my life living in a house where the water came from a stream off the hills, through a rusty piece of chicken wire (the filter) and into a galvanized tank in the back garden. We always figured that so long as the frogs that lived in the tank looked healthy then so would we be. On the down side, we did have to fish the occasional dead sheep out of the tank, but it did add to the flavour ;)
     
  11. KIAB

    KIAB Super Member

    Biofuel boilers are so underated, shame we don't make more use of them here.:(

    It's the same with geo thermal, we should make more use of it.
    Plus, your eliglble for Renewable Heat Incentive (RHI) scheme, not sure if it's still around, a bit rusty on it nowadays.
     
    Last edited: Dec 11, 2016
    Joe95 likes this.
  12. sospan

    sospan Screwfix Select

    I haven't got the plans to hand but it was using two heat stores which could combine to store the amount of hot water. If I recall each of the heat stores had multiple inputs each with their own coils. So there shouldn't be a need to have a complex switching mechanism, the only potential problem will be too much hot water which we will have to put into the bore hole and pull back when the other sources aren't at peak.

    I got a room which will take "submarine" type batteries to store surplus solar power. There will be a diesel back up generator to supply power should I run out of battery/solar and mains power fails. This I expect to be really fiddly to set up. The house wiring will also be quite interesting as it will be split between the standby circuits (heating, freezer, certain lights, alarms and internet) and normal use.
     
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  13. Hemel

    Hemel New Member

    Can I ask what the cost was? I'm interested in the pay-back period.
     
  14. Joe95

    Joe95 Screwfix Select

    I have been pondering the idea for years and years now, and may at some point implement a similar solution.

    May i suggest you look at this video:


    It is what gave me the idea in the first place after a was shown by a mate, very interesting method.
     
    KIAB likes this.
  15. Joe95

    Joe95 Screwfix Select

    I will draw out a plan of how it works and upload a picture.
    I was trying to find some pictures but i do not think i have them on my computer :(

    As long as the appropriate measures are taken out to prevent the contamination of mains water and the rainwater, you should be fine. For the sake of a few correctly placed valves like these:
    http://www.screwfix.com/p/double-check-valve-dzr-22mm/26003
    It is not worth the risk of having your incoming water removed, as the waterboard could cap off your supply.

    I will look for the invoices now, i cannot remember the exact price.
     
  16. sospan

    sospan Screwfix Select

    My need for a system like this is driven by a few things - our power supplies and water is very vulnerable to loss through nature, deliberate outages caused by vandalism/ terrorism and of course rising prices.

    Not really a survivalist but general population don't realise how vulnerable our infrastructure is. It would be so easy for someone to contaminate a reservoir or take out an electrical substation. Our supermarkets only have a few days supply of food in them and rely on items being delivered to them many times a day, so if we get a run of bad weather we could be in an interesting position in terms of basic necessities.

    So my plan is to have enough food, water and fuels to last a few weeks in comfort rather than struggle. When you work out the costs for having a mixed system on a large house (650 sqm) it isn't too bad. It also gives me a chance to recycle all the off cuts of timber, sawdust and packaging I go through.
     
    Joe95 likes this.
  17. Joe95

    Joe95 Screwfix Select

    Here is the simplified plan,
    IMG_7244.JPG

    The costs for this install:
    Tank: £1500
    UV filter: £400
    Motorised valve, pump & water sensor: £350
    Manual valves, check valves & all brass/compression fittings: £80
    Pipe, brackets, insulation & end feed accessories: £980
    Cable, enclosures, connectors & Misc. electrical: £75
    Labor for entire rainwater install and pipework to toilets was 16 days and at a cost of £2000
    (Labor for bathroom and rest of install was 20 days. The automated sensor flushes and all bathroom fixings were in excess of 10 thousand.)

    Many of the things about this install would be much, much cheaper doing it in a domestic environment with 2/3 toilets. For example;
    - The tank you already have
    - The UV filter would be much cheaper for a smaller tank, and could be one on a timer that is not rated for 24/7 operation, as the one in my installation was, it is also overrated for the tank size but this ensures bacteria growth does not occur.
    - The bulk of the work could be done yourself, if not all if you feel confident. You could do all the plumbing yourself and have a plumber/electrician come in and do the wiring side.
    - The pump could be a small shower pump, as these use a paddle switch, which turns the pump on only when this is required. Also remember that this may not be required, as it is only cisterns you are filling, which do not require immediate and high pressure water, so gravity could do this. The pump was required here as the pipes were in the ceiling, so the water had to go above the height of the tank.
    - The motorized valve and water sensor are completely optional, if you do not require this you could go for a manual option. It was required for this install as no-one would be regularly checking to see if the toilets flush. Bear in mind this automated system would be a minimum of £120, although it would save you visiting the loft every time the water runs out, and would only need visiting during a power cut, or a valve failure (both highly unlikely).

    I reckon for a domestic install of an automated rainwater system, with the parts you have & without labor costs, you could have it for around £250-£350.

    Regards,
    Joe :)
     
  18. Joe95

    Joe95 Screwfix Select

    There was a TV program on this a few years ago, they were showing how easy it was to break our infrastructure and the effect of it. It was quite scary to imagine.
    So, at least you will be ready for when it eventually happens, as I'm sure it will at some point, you will be ready. :cool:
    With everything connected to the internet now I'd imagine it could all be hacked into. :eek:
     
  19. Joe95

    Joe95 Screwfix Select

    With multiple inputs, i suppose there is the potential for multiple heat sources to be connected, so in theory you could have a gas boiler as a backup if you run out of combustible material.
    There is so much that could go into one of these systems that you could spend days planning:oops:

    I will have to contact a firm soon, as i should get some more information and possibly some plans drawn up. Its on the never-ending list:rolleyes:
     
  20. Joe95

    Joe95 Screwfix Select

    Exactly, the savings that can be made through these systems are huge, which does make me wonder why they are not more popular.
    Instead most are stuck with gas over-consuming, expensive and unreliable(for the most part) gas boilers.
     
    KIAB likes this.

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