Filtering greywater

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Brianellul
Brianellul Solar Expert Posts: 95 ✭✭
in Energy Use & Conservation #1
Hello

I'm thinking of collecting my washing machine waste water and use it for toilet flushing. My idea was to first filter the waste water using a sediment filter and then pass it through a carcoal filter before stroring it and eventually being used in the toilet flushing system. Do I need to filter/clean the water any further? and if yes what other stages would be needed?

Regards
Brian
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #2
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    Re: Filtering greywater

    A sand filter is probably your best bet. cheap and easy to make. If the water will be stored for any length of time you may want to get some chlorine tabs from a pool store to keep away the algee. The tabs have a longer shelf life than liquid bleach. I wouldn't waste the charcoal if it is not for drinking.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
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    Re: Filtering greywater
    Seven wrote: »
    A sand filter is probably your best bet. cheap and easy to make. If the water will be stored for any length of time you may want to get some chlorine tabs from a pool store to keep away the algee. The tabs have a longer shelf life than liquid bleach. I wouldn't waste the charcoal if it is not for drinking.

    Agree, but if you don't need the chlorine, don't use it, as it will also kill off the required/necessary bacteria that allows your septic disposal system do it's job of digesting the waste.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #4
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    Re: Filtering greywater

    You do not want to use the first drain of your washing machine for a gray water source... Too much soap/oils/particles in the water.

    Decades ago, I had seen that Kenmore (Sears--as I recall) had a washer that had a diverter valve on the output. It recycled soapy water for reuse and rinse water out another pipe. Perhaps a simple timer or manual valve on the washer to divert rinse water will make things easier.

    Using bath water/bathroom sink water is a better source.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #5
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    Re: Filtering greywater
    waynefromnscanada wrote: »
    Agree, but if you don't need the chlorine, don't use it, as it will also kill off the required/necessary bacteria that allows your septic disposal system do it's job of digesting the waste.

    Did not consider the fact that he may be on a septic system. Thanks.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #6
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    Re: Filtering greywater

    greywater needs to be used within the hour, or it should be sterilized. Otherwise, it's too full of tasty (to microbes) stuff, and it goes rancid really fast.

    You can build an "aquapond" with slowly moving water and water plants, which will filter it pretty well, and then store that water.

    Sand filters will clog within the day with graywater.

    OR, use the last rinse water, as the source for the WASH water for the next load. That's ok to store for 20 minutes. and won't leave "crud" in your toilet.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
    #7
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    Re: Filtering greywater

    YeaH, without bleaching the water the grey water used in the toilet developed black moulds and stinkys. Eventually got a looooow volume flusher and removed the tank/pump from the basement. But nice in theory.

    Ralph
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  • Brianellul
    Brianellul Solar Expert Posts: 95 ✭✭
    #8
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    Re: Filtering greywater
    Seven wrote: »
    Did not consider the fact that he may be on a septic system. Thanks.

    Should have mentioned that before.... but no I'm not on a septic tank
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  • Brianellul
    Brianellul Solar Expert Posts: 95 ✭✭
    #9
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    Re: Filtering greywater

    Thanks to all for your replies!

    I thought that this was a simple & inexpensive to achieve, however I must rethink it all now. I was planning to dump the water in a 500l tank, which is already being used, since I'm dumping the water of the ACs, RO and kids pool into it.
    My plan to filter the water before dumping in the tank was exactly to remove the soap and particles which are present in the machine waste. The filter must not get clogged every day or two, however it's not a problem if it will need cleaning every month or so... I'll just add this new task to my calendar.

    As suggested, I can place chlorine or bleach tabs in the tank to eliminate the possibility of development of moulds in the toilet... hehe if it happens or the water stinks, I'll have to revert back everything... my wife already hinted me to make sure that it will all work before doing it

    Thanks all for your help.
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  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    #10
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    Re: Filtering greywater

    I am wondering if a sand filter wouldn't work, possibly substituting the sand for a larger grain rock, say peagravel, would. Maybe something in between. It is the surface area that you want. You could always pour it through a sheet or pillow case first.
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