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Inefficiency of conventional sewage system?

  • 19-10-2009 10:25am
    #1
    Registered Users Posts: 4,848 ✭✭✭ Cianos


    I am wondering about the efficiency of the conventional sewage system. Doesn't the usage of water as a means to transport waste seem very outdated in this day and age? A massive volume of water is used to carry a comparatively tiny amount of waste in ratio.

    Especially nowadays with water charges being proposed, could it be time to look at other solutions? Some kind of chemical based unit where the waste is stored temporarily and even collected in special containers once a week along with other household waste?

    Water based sewage management has been in use for millenniums and probably every new residential development has used it since, presumably simply because it's the standard.

    Thoughts?
    Tagged:


Comments

  • Registered Users Posts: 8,781 ✭✭✭ Carawaystick


    I've seen waterless urinals in Ikea in Down, They just about work, there's a bit of a hum in the gents
    I've used pit toilets in France and in Peru. In Peru, they were sited at altitude where it's much drier so the pit contents dehydrate and don't smell as much.

    Then you have chemical toilets. enough said.

    and lastly as a solution that works the vacuum toilets as seen on Ferries and planes. These need a power supply to generate the vacuum, which when at sea or in the air is a given. They would add an unnecessarily complicated layer to domestic and commercial wc's


  • Registered Users Posts: 5 ✭✭✭ PatrickBoylan


    You also have the incinerating toilet option. There are also waterless urinals with a liquid trap so there is no smell. I think there is also a deep freeze toilet option where your poo is frozen solid.


  • Registered Users Posts: 3,278 ✭✭✭ dubhthach


    In general though I would think part of the issue is that our Sewers are "combined sewers" as a result they carry both sewage and surface runoff. This massively increases the volume of liquid that needs to be treated.


  • Closed Accounts Posts: 7,230 ✭✭✭ Solair


    dubhthach wrote: »
    In general though I would think part of the issue is that our Sewers are "combined sewers" as a result they carry both sewage and surface runoff. This massively increases the volume of liquid that needs to be treated.

    A lot of our sewers are actually not combined. There are separate surface water and waste water in most major urban areas in Ireland where sewers were re-laid. I know in Cork City even a lot of the older areas have separate foul and surface water drains going back to the 1920s and before.

    The problem is that where they are combined, they can be overwhelmed with the Irish weather and result in serious pollution of rivers.


  • Registered Users Posts: 5,278 ✭✭✭ dowlingm


    one thing that would help is better use of grey water - bath/shower/washing machine runoff - to flush toilets and so on.


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  • Closed Accounts Posts: 7,230 ✭✭✭ Solair


    dowlingm wrote: »
    one thing that would help is better use of grey water - bath/shower/washing machine runoff - to flush toilets and so on.

    There's absolutely no reason in Ireland why we couldn't use rain water to flush toilets. A lot of modern commercial and public buildings use 'grey water' systems that collect roof water to use for those kinds of purposes.

    There's absolutely no reason, in a country that rains as much as Ireland, to use drinking water to flush the loo!

    Washing machine and shower run-off is fine, but the only problem is that it can create a lot of foam in the toilet as it contains detergents (laundry products, shower gel etc) and fabric softener etc. It can also contain a lot of lint (fluff) from clothes, debris like buttons, coins, body hair and other gunk that can clog flush-mechanisms on toilets.

    You would either need to radically redesign the toilet flush mechanism to handle that kind of stuff, or else filter the water to remove at least any solids.


  • Closed Accounts Posts: 6,084 ✭✭✭ oppenheimer1


    Solair wrote: »
    There's absolutely no reason in Ireland why we couldn't use rain water to flush toilets. A lot of modern commercial and public buildings use 'grey water' systems that collect roof water to use for those kinds of purposes.

    There's absolutely no reason, in a country that rains as much as Ireland, to use drinking water to flush the loo!

    Washing machine and shower run-off is fine, but the only problem is that it can create a lot of foam in the toilet as it contains detergents (laundry products, shower gel etc) and fabric softener etc. It can also contain a lot of lint (fluff) from clothes, debris like buttons, coins, body hair and other gunk that can clog flush-mechanisms on toilets.

    You would either need to radically redesign the toilet flush mechanism to handle that kind of stuff, or else filter the water to remove at least any solids.

    At the moment we use drinking water in toilets because it is cheaper than rainwater harvesting.


  • Registered Users Posts: 514 ✭✭✭ con1982


    Toilets create a relatively small percentage of domestic waste water (foul water). Most foul water comes from showers, wash hand basins and sinks; which require the use of water. So, i think the conventional sewage system is still fit for purpose.

    I agree with a poster above that rain water should be used for flushing toilets. I would like to see all new build homes required to be constructed with grey water toilets. Ideally gravity fed rain water as opposed to collecting below ground and pumping up to holding tanks.

    We also need nationwide water meters.


  • Closed Accounts Posts: 7,230 ✭✭✭ Solair


    At the moment we use drinking water in toilets because it is cheaper than rainwater harvesting.

    At present for non-metered domestic premises maybe, but a lot of commercial premises have to pay per cubic metre.

    For example, Cork City Council charges €2.35 per cubic metre for water to commercial users.

    http://www.corkcity.ie/services/finance/collectionrevenue/


  • Closed Accounts Posts: 6,084 ✭✭✭ oppenheimer1


    Solair wrote: »
    At present for non-metered domestic premises maybe, but a lot of commercial premises have to pay per cubic metre.

    For example, Cork City Council charges €2.35 per cubic metre for water to commercial users.

    http://www.corkcity.ie/services/finance/collectionrevenue/

    When the cost of the infrastructure: tanks, pumps, filters, treatments and maintenance is taken into account, rainwater harvesting is still more expensive than metered water at present.

    I know someone who did a Cost/benefit analysis on it.


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  • Registered Users Posts: 7,661 ✭✭✭ Markcheese


    Just about to hook a rain water tank to everything but my kitchen tap... 1000 litre ibc tank 60 euro... Couple of valves, ball valve..filter( old tights) and a pump 60/70 from lidl or about 200 for a good one ... But I live in a very hard water area... So don't have to run and buy a filter...

    Slava ukraini 🇺🇦



  • Closed Accounts Posts: 6,084 ✭✭✭ oppenheimer1


    Markcheese wrote: »
    Just about to hook a rain water tank to everything but my kitchen tap... 1000 litre ibc tank 60 euro... Couple of valves, ball valve..filter( old tights) and a pump 60/70 from lidl or about 200 for a good one ... But I live in a very hard water area... So don't have to run and buy a filter...

    You'll need better filters than an old pair of tights if you want to use that water. That water will foul in the tank, and if it is going to be used for washing it needs both particulate and UV treatment. Water hardness in your area is irrelevant when it comes to rainwater collection, as rainwater is naturally free from carbonates.

    Even if it was just being used for toilets, I would give it that treatment too.


  • Registered Users Posts: 4,848 ✭✭✭ Cianos


    Bill Gates put the question out there for a competition.


  • Registered Users Posts: 7,661 ✭✭✭ Markcheese


    Markcheese wrote: »
    Just about to hook a rain water tank to everything but my kitchen tap... 1000 litre ibc tank 60 euro... Couple of valves, ball valve..filter( old tights) and a pump 60/70 from lidl or about 200 for a good one ... But I live in a very hard water area... So don't have to run and buy a filter...

    You'll need better filters than an old pair of tights if you want to use that water. That water will foul in the tank, and if it is going to be used for washing it needs both particulate and UV treatment. Water hardness in your area is irrelevant when it comes to rainwater collection, as rainwater is naturally free from carbonates.

    Even if it was just being used for toilets, I would give it that treatment too.


    Ah balls .. That plan scuppered... Why would the water foul ,..currently have a couple of large ( open) storage tanks in my attic... They dont foul ..and in Australia and Nz they use rain water tanks (with minimum filtration) in a lot of places

    Slava ukraini 🇺🇦



  • Closed Accounts Posts: 6,084 ✭✭✭ oppenheimer1


    Markcheese wrote: »
    Ah balls .. That plan scuppered... Why would the water foul ,..currently have a couple of large ( open) storage tanks in my attic... They dont foul ..and in Australia and Nz they use rain water tanks (with minimum filtration) in a lot of places

    Bird droppings and other organics that get washed into the system are what fouls the water. Toilets require minimum treatment, while higher levels are required for washing. Large volumes of standing water will stagnate.

    As I said earlier, rainwater harvesting isn't as straight-forward as it seems. Its why it compares poorly in economic terms with mains supply.


  • Closed Accounts Posts: 7,230 ✭✭✭ Solair


    Considering the amount of rain we get in Ireland, it seems madness not to use it for something!


  • Registered Users Posts: 7,661 ✭✭✭ Markcheese


    Now I'm extra confused... People use grey water to flush the loo.. Why would you want to treat rainwater to flush the loo..am planning on using a diverted so first couple of mins of rain won't go into tank...not going to be standing water as it'll be used daily out of tank..

    Slava ukraini 🇺🇦



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