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-   -   Gray water to flush toilet ? (https://www.irv2.com/forums/f258/gray-water-to-flush-toilet-147581.html)

Bug512 01-07-2013 08:06 AM

Gray water to flush toilet ?
 
So I am looking into making a system (pump, valves and filter) to use our gray water to flush the toilet.

Anyone here know of anyone who made a system to do this?

pumper9x9 01-07-2013 08:32 AM

Interesting idea, but you may have to clean the toilet more often, it will smell like gray water, and you'll need to leave some amount of gray water in the tank or put some in it for it to work. If your intent is just to save room in your gray water tank so the black water tank is close to full when the gray water is you might try washing and rinsing dishes in a tub and then dump that down the toilet, collecting the shower water that you run to get the water hot in the same tub and use it to wash the dishes. Or install a system to transfer some gray water to the black tank. Unless you do a lot of boon docking this might not be worth the effort. Also if you do a lot of boon docking you might consider a sun shower and take your showers outside. You might also consider getting one of those portable dump tanks. The more complicated you make the systems the more stuff there is to screw up and break. There are probably a bunch of unintended consequences that will be discovered after you set the system up.
Good Luck

RickO 01-07-2013 08:47 AM

I've never heard of it being done but it sounds like a GREAT idea to me!

Good luck with it.

Rick

Ed-Sommers 01-07-2013 10:16 AM

That is not an unknown resource in the Boondocking world but I know of no "plans" for doing so but remember that a few discussions (I know not where), recommended the source of the gray water be up off the bottom, and if bleach is in the gray water, it is not appropriate for the black tank because it kills the bacterial action going on in there which is important for boondocking, and fulltime, but not a factor for weekender's.

Ed

JohnBoyToo 01-07-2013 10:26 AM

Novel idea,
would save fresh water for use elsewhere
but I wonder if there is a law against connecting black water to grey water?
(which (via piping) is connected to fresh water)

You'd have to have some valves and pumps for sure.... Have to think on this a while...

others have tried it:

Recycle Bathwater to Flush Toilet - YouTube

Bug512 01-07-2013 10:54 AM

Here is my reason. We boondock (at music festivals) or have limited hookups when we camp and conserve as mush freshwater as we can. It's painful to see nice clean freshwater being used to flush the toilet. This also give a little more room in the gray tank also.

So my idea is to draw gray water from the holding tank and use a demand water pump just like the freshwater tank uses. I think a filter before the pump would be a good idea to protect the pumps and valves on the toilet from particles that are suspended in the gray water.

I would bring the feed line into the toilet room and have a series of quick connects to "unplug" the freshwater from the toilet and then connect the gray water line. I would not rely on any three way valve as a means of isolating the gray water flush line to the fresh water system.

Or I could use a three way valve and put a check valve in the freshwater line. that would be to means of a stop.

So the process begins.

Thanks for everyones input.

Sky_Boss 01-07-2013 11:51 AM

I think it could be a good idea with a few assumptions.

1. We found that in our Winnebago with 51 gal black and 53 gal grey that we would have to dump the grey tank 2-3 times as often as the black. (We tested this out in our CG for future reference.)

2. If one chose to use CG toilet facilities to some extent then I would think one could make a significant increase of time between dump by channeling grey water to the black tank.

3. The big caution would be on having full fresh water and full waste tanks with the associated weight until dumping could be done. I once had full water and 1/2 black & grey tanks and exactly maxed out my rear axle on the gasser. :banghead:

These thoughts assume that the reason to conserve water is more based on camping without sewer hook ups or boondocking instead of hyper water conservation beliefs.

I don't know about any sidebar issues relating to the affects on grey water on black tank odors and such. That could cause other issues.

MRBB 01-07-2013 11:52 AM

If you have 2 grey tanks and use the shower tank this would work but you don't want to use the kitchen sink tank. The grease will stink more than the black tank and clog up the valves and leave a nasty ring in the toilet along with a very bad smell.

TdogKing 01-07-2013 02:10 PM

Sounds like a good idea to me . I don't think it would all that hard to do. Like you said the biggest problem is keeping gray water particles from plugging your pump. We don't and never have put grease down our kitchen sink . Even if you had to wipe down the toilet here and there its not the end of the world and paper towels are easy to dispose of. I would come up with a system that pulls grey water from a couple inches off the floor of the grey tank and most likely you might not have clogging problems. Keep us posted .

vsheetz 01-07-2013 03:14 PM

How about a rainwater collection system - use this to flush.

fastcat 01-07-2013 03:18 PM

My wife would not tolerate the smell and the extra cleaning. Maybe yours is more forgiving. :thumb:

Traps90 01-07-2013 04:34 PM

Quote:

Originally Posted by fastcat (Post 1423318)
My wife would not tolerate the smell and the extra cleaning. Maybe yours is more forgiving. :thumb:

My wife would kill me if I tried that:banghead:. She's good for 2 maybe 3 nites boondocking and then back to FHU's:D

TdogKing 01-07-2013 04:38 PM

Are you telling me your grey water smells worse than what you leave in the toilet ??? There is no smell of nothing once you push the pedal and flush...At least in my Motorhome anyway .

ChooChooMan7 01-07-2013 04:47 PM

I would think about an aquarium sand filter. Just my 2 cents.

I have seen setups like this on the net. It is a great idea.

Bug512 01-07-2013 05:35 PM

From some of the replies above.
Since we camp at festivals finding freshwater or a place to dump onsite is a little scarce sometimes. Almost the same goes for state parks where electric only sites are the norm out there.

I have found quick connect fittings (self sealing) in the McMasterCarr catalog, I am going to investigate some different pumps. Maybe I do not need a demand pump, maybe just a momentary switch in the bathroom closet?? One plan was to draw off on the 3" gray water dump valve with a cap that has the garden hose thread on it.

No interest in collecting rain water and I do not have two separate gray water tanks.

Again thanks for all the ideas and comments. If I do go through with this I will keep this thread posted.

bluepill 01-07-2013 05:44 PM

I have used the low-tech version of this a few times. I drain the gray water into a pail at the normal drain (being careful to open the valve only slightly), then carry the pail into the toilet and dump it. Ten trips give me about 30 gallons of transfer, and gives me something to do while DW "puts on her face" in the AM. :)

TQ60 01-07-2013 05:48 PM

using the cover makes for easy connection, you could get various filters to keep stuff from pump.

At toilet you need to get clever, some check valves for safety and a three way valve would allow switching sources, pump has built in pressure switch.

Can be set up all electric, interesting project

Barlow46 01-07-2013 05:51 PM

I would consider using a "raw water" wash down pump w/pressure shutoff sensor from the marine world and just run a line with a shutoff valve into an area beside or behind the toilet. Then hookup a typical hand held faucet "sprayer" to fill the toilet bowl before flushing. This would allow you to clean out the raw water wash down pump screen should grey water particles try to clog it. Sounds like a great idea to me and if you can keep it simple it could be sold as a kit. The boating world has some great fittings for what you want to do.

MRBB 01-08-2013 12:39 PM

Quote:

Originally Posted by TdogKing (Post 1423251)
We don't and never have put grease down our kitchen sink . .

Well, every time you "wash" your dishes you put grease down the drain... If you have ever smelled a grease trap they smell worse than any septic tank.

Bug512 01-08-2013 12:48 PM

We have and maintain our grease traps at our training facility, not fun or pleasant smelling.
The difference is grease traps separate the grease and the water. A gray water tank has both the water and grease combined with the grease being suspended in the water from surfactants that are in our soaps and detergents.

I doubt the water that I use in the toilet will have that much of a negative impact vs. all the other impurities going into the toilet.

So is anyone else looking to do this?

TdogKing 01-08-2013 12:56 PM

@ MRBB....we hardly cook anything in grease and if if makes its own such as Hamburger then the pan is wiped clean with a paper towel then washed . We don't put any grease down our drains. I've owned/ camped in RV's over 30+ years and never has grease smell been a issue and if it might be I empty the trash and all traces are gone. Understand everyone cooks and camps different but that's our way.

MRBB 01-09-2013 11:25 AM

Quote:

Originally Posted by TdogKing (Post 1424293)
@ MRBB....we hardly cook anything in grease and if if makes its own such as Hamburger then the pan is wiped clean with a paper towel then washed . We don't put any grease down our drains. I've owned/ camped in RV's over 30+ years and never has grease smell been a issue and if it might be I empty the trash and all traces are gone. Understand everyone cooks and camps different but that's our way.

It's a great idea and if you can get it to work for you then more power to you. I have 2 grey tanks so taking water from the shower and bath sink is fairly clean so it would work well for me. :thumb:


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