What about this gray water recovery system?

March 19, 2008 11:08 PM

I'm kicking off a major home renovation and looking for some green innovations I can incorporate without breaking the bank. This gray water recovery system looks promising.

The AQUS system sells for about $300.00 per toilet. Does anyone have experience with this system? Is it practical? Is it funky? I've read where the gray water can mess up the toilet hardware with time. You have to feed the reservoir tank bromine and chlorine tablets to kill bacteria in the sink waste water. Is it nasty? Is this more pain than it's worth? Any feedback is appreciated.

posted by wsg to home & garden (6 comments total)

It rings alarm bells for me.

Error: Storage of grey water
Error: Pump enthusiasm

and while it's nowhere near as expensive as the systems criticised here,

Error: Automated reuse systems for flushing low usage (e.g., residential) toilets

I would be very surprised indeed if the water savings would pay for the required disinfectant tablets (economically or energy-wise). Replacing those tablets would be a chore, and failing to do it would make your toilet cistern grow all kinds of interesting things. Also, I would be loath to set up a system that dumps chlorine and/or bromine into the drains every single time you flush.

Just run the sink water straight into a mulch basin around a fruit tree.
posted by flabdablet at 3:28 AM on March 20, 2008

In addition to what flabdablet says, any savings with this are going to be incredibly marginal. Unless you have very unusual bathroom habits, you just aren't putting all that much water down the bathroom sink (common use would be, per person, two tooth-brushings, five or so handwashings, face-shaving, and perhaps something else like rinsing your dentures or something -- none of which involve running the sink very long, especially if you are being a good water conserver who turns the water off while scrubbing your teeth). Moreover, all of that water is especially dirty greywater -- very dark grey greywater, one could say, with the toothpaste and shaving scum and soap and so on. (Your bathtub puts out much cleaner greywater, for comparison.)

So your sink will capture perhaps two or three gallons in a day, which is the same as one toilet flush (or half a toilet flush, if you have an older toilet); you could get the same savings with zero cost and trouble by once a day doing a "yellow is mellow" flush-avoidance, for example, or by having your lawn irrigated for a few less seconds, or shortening your shower by one minute. Even the maximum savings claimed on your first link, 7 gallons, can be achieved by shortening your shower by 2-3 minutes.

So yeah, run the sink water out to a water-loving tree (will banana trees grow where you are located in Florida?) or mulch-bed, and if you really want to use non-city water for the toilet, consider using captured rain water, because it is so much cleaner and more toilet-friendly.
posted by Forktine at 6:41 AM on March 20, 2008

Also, pets and small children will often drink out of toilet bowls -- I'd want to know what the potability of that semi-treated greywater would be like before allowing that to be available in my house.
posted by Forktine at 6:44 AM on March 20, 2008

I don't have anything to offer regarding the grey water system, however, if you are looking to do other green renovations, you should contact the Earthways Center. They have literally hundreds of sources for environmentally-friendly materials.
posted by Ostara at 7:34 AM on March 20, 2008

How about one of those toilets that lets you wash your hands with the refilling water?

Wikipedia picture, "Hack a toilet for free water" at Instructables

From what I've heard, these type of toilets are more common in Japan than the US.
posted by philomathoholic at 1:46 PM on March 20, 2008

You can also connect a garden hose to the water outlet of your washing machine, and run the other end of the hose out to your lawn. Gray water + phosphates = happy lawn! Just remember to move the hose every once in a while so different parts of the lawn get watered.
posted by dylan20 at 10:38 PM on March 20, 2008