trashcanman
Mechanical
Has anyone here designed a grey water system? I speak of a type that uses the grey water for flushing toilets and urinals, no irrigation.
Please list do's and don'ts. Thanks.
Please list do's and don'ts. Thanks.
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Grey Wate System
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ChrisConley
Mechanical
The codes in Canada are just starting to include the possiblity of grey water reuse. CSA has a standard and CMHC is creating a guideline.
Having said that, everytime I get asked to design a grey water system it gets stopped at the 'how big a space do you need for a tank and treatment area?' the second big stop comes from 'how much do we save a year?'.
A systems with low flow toilets, ultra-low flow, or zero flow urninals and low flow faucets will reduce water usage significantly (52%) and don't have the maintenance issues that grey water has.
Having said that, everytime I get asked to design a grey water system it gets stopped at the 'how big a space do you need for a tank and treatment area?' the second big stop comes from 'how much do we save a year?'.
A systems with low flow toilets, ultra-low flow, or zero flow urninals and low flow faucets will reduce water usage significantly (52%) and don't have the maintenance issues that grey water has.
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trashcanman
Mechanical
Thanks Chris. A couple of questions,
You mentioned tank size. It is my understanding that grey water should not be stored for more than a day, else it turns septic. What size do you use? For the system I have in mind (serving 10 flush tank WC and 4 urinals), 100 gallons should be more than sufficient.
You also mentioned treatment. What treatment besides filtration are you speaking of? A lot of treatment sort of defeats the purpose of re-using the water, no? Thanks.
You mentioned tank size. It is my understanding that grey water should not be stored for more than a day, else it turns septic. What size do you use? For the system I have in mind (serving 10 flush tank WC and 4 urinals), 100 gallons should be more than sufficient.
You also mentioned treatment. What treatment besides filtration are you speaking of? A lot of treatment sort of defeats the purpose of re-using the water, no? Thanks.
ChrisConley
Mechanical
Beyond filtration the standards appear to be coming out requiring some chemical treatment (mainly disinfection), at least in Canada.
There may be also requirements for 'clarifiers'.
I'd crosspost over at
Asking what the recommended treatment for greywater for reuse is.
There may be also requirements for 'clarifiers'.
I'd crosspost over at
Asking what the recommended treatment for greywater for reuse is.
Beyond structural and joining requirements I think in general any potable and non-potable water sources and transmissions in close proximity require care on the part of a lot of parties (including designers, installers, later mechanics or whoever tapping etc.) Recent standards e.g. that you can read for yourself at (and for wastewater,just replace "water" in the URL) give quite a bit of guidance etc. with regard to many proximity and other issues. Notice that of all of the standards rigamerole having to do with with parallel or various "crossings" (consisting of intersecting pipelines or pipelines going across other sources of potential contamination or sensitive structures/environments/features etc.) is also immediately followed by passages in these standards about preventing "cross-connection" etc.
Maybe particularly if there is any chance that the potable water line in the area may have to be dug up and tapped for connection in the future it would be a good idea when the parllel installation or crossing is made to also to well-mark the lines (all kinds of pipe can of course now be durably marked for the services in such locations with very close parallel or even colored/labeled/marking tapes spirally wound around the pipes, special colored and/or labeled polyethylene wraps, or other means, and of course taps could even conceivably be installed to draw off and test samples of withdrawn water from any suspect pipe/line before someone drinks from a new service (as appears to be at least hinted in some crossing areas of standards). Where potable water and other pipes etc. must be installed in close proximity, there may also be some value to very strong/robust (impact/gouge/damage-resistant etc.) pipe materials in general, as "stuff happens" and maybe particularly in such congested areas.
Maybe particularly if there is any chance that the potable water line in the area may have to be dug up and tapped for connection in the future it would be a good idea when the parllel installation or crossing is made to also to well-mark the lines (all kinds of pipe can of course now be durably marked for the services in such locations with very close parallel or even colored/labeled/marking tapes spirally wound around the pipes, special colored and/or labeled polyethylene wraps, or other means, and of course taps could even conceivably be installed to draw off and test samples of withdrawn water from any suspect pipe/line before someone drinks from a new service (as appears to be at least hinted in some crossing areas of standards). Where potable water and other pipes etc. must be installed in close proximity, there may also be some value to very strong/robust (impact/gouge/damage-resistant etc.) pipe materials in general, as "stuff happens" and maybe particularly in such congested areas.
MikeHalloran
Mechanical
St. Petersburg, Florida has a citywide system for reclamation and re-use of gray water, already in place. Searching on that may eventually yield something you can use.
Mike Halloran
Pembroke Pines, FL, USA
Mike Halloran
Pembroke Pines, FL, USA
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