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Sneakinup · 11-04-2003, 11:48 AM

Slightly off the intended subject (within the originally posted thread), but... has anyone ever thought of using a 12v water pump between the gray or auxilliary blue tank to the toilet for flushing? I've been reading a lot about boondocking, and they tell you to save your gray water for flushing the toilet. I would think that a simple pump could be hooked up to do this all the time, therefore cutting down on the amount of water ending up in the gray tank, since gray water is in greater abundance. And in the long run, you save water, both from your fresh tanks and the world in general!

I would think the added battery use would be negligible, and second pump would only work for the toilet anyway.

I could be way off here. LOL

Just the ramblings of an AA (Airstream Addict). I need to get a life.

Italics added by InsideOut when thread split

InsideOut · 11-04-2003, 12:58 PM

I thought this discussion deserved it's own thread...

Quote:

... has anyone ever thought of using a 12v water pump between the gray or auxilliary blue tank to the toilet for flushing? ...I would think that a simple pump could be hooked up to do this all the time, therefore cutting down on the amount of water ending up in the gray tank, since gray water is in greater abundance.

Couple of issues come to mind, nothing insurmountable, but they would have to be considered...

1. I would imagine you would need some sort of strainer between the blue/grey tank and the pump to strain food particles so they don't clog the pump.

2. Most dishwashing detergents would negate the effects of the toilet chemicals trying to do their job.

3. What would you do when you did have full hook-ups? Same set-up? Would you by-pass the freshwater hook-up for the toilet or have an either/or type switch?

4. As long as the black tank has the capacity and you aren't tempted to use more water because it's recycled.

I like the idea...just wondering how to make it work...

Shari

wahoonc · 11-04-2003, 01:25 PM

I have seen houses set up this way, basically all they did was put a strainer in the system to clear out the big stuff. Gray water from showers and washing machines was used for toilets and watering the gardens. IIRC the sink water bypassed the inside system because of the food particles, but it came back in as part of the outside irrigation system. One of the systems was in use in the southwest and another in Vermont. Not sure what the Vermonters did in the winter with the outside water.

Sounds like it might just work, specially for those people that don't have grey water tanks

Aaron

87MH · 11-04-2003, 01:49 PM

Pass the sprayhead into the bath, or rig it up through the floor with a disconnect at the pump and the pump inlet to the blue tank.

A suction screen should keep the sprayhead internals fairly clean.

The pump could be the same size as the house pump, affording a spare (with a little cleaning and sanitizing) should the main house pump fail.

Quick disconnects for pump suction, discharge, and electric hookup would insure a minimum of hookup and disconnect time.

In addition, the pump hooked to the blue tank, and fitted with a non-potable discharge hose would allow discharge to a nearby shower/toilet facility. The black and gray water go to the same sewerage facility, so contents of the gray water should be a nonissue if discharged to a toilet. Might save a long drive or pull with the blue tank should true dump sites be few and far between.

Moonshot · 11-04-2003, 02:25 PM

Interesting idea, Sneakinup.

My former SOB had a recirculating toilet. I think some folks call this a macerator. The liquid that goes into the toilet is recirculated back when you flush.

Now, before you get totally grossed out it works rather well. If you use proper chemicals there's hardly no smell either.

Thetford makes this toilet. I think they are more widely used on boats and airplanes than RVs. Mine had a 6 gallon capacity and would fill up within 2 days use with a family of four.

Granted this is not a good option for most Airstreamers, but might work for popup campers and the like.

Scott

wahoonc · 11-04-2003, 02:53 PM

Quote:

Originally posted by 63wind
Interesting idea, Sneakinup.

My former SOB had a recirculating toilet. I think some folks call this a macerator. The liquid that goes into the toilet is recirculated back when you flush.

Scott

Scott,
The Trail Manors still use that toilet, which I guess counts as a popup, all be it an expensive one

I saw one in a mid 70's class C too.

Aaron

garry · 11-04-2003, 02:55 PM

What about the dish washing soap you use in the sink ? It would tend to "foam up" on transfer or if you were under way and it was sloshing around in the black tank !!

In addition when washing greasey stuff in the sink it would tend to leave a grease film in the black tank and toilet bowl.

While it sounds like a good idea I would only recycled the shower and bath sink as it would be less of a problem due to the above.

Garry

Sneakinup · 11-04-2003, 02:56 PM

So I am not crazy? Well... that is debatable.

I do like the idea of having an extra pump on board in case of a failure. They aren't that expensive, and you can get used ones for next to nothing.

The added thought of using the pump to empty the gray tank and flush through the black tank is also a good idea.

I thought perhaps the toilet would be disconnected from the main water line, with maybe a diverter valve if you wanted to use city water, but that wouldn't really be necessary. One additional benefit of this system would be that all (or some) of your gray water ends up in your black water tank, which for a trailer that was originally only designed for black water, would better balance the trailer in the event you had to move with a full load. Of course, that would all depend on a lot of things. Number of flushes, lengths of showers, dish washing, teeth brushing, etc., and gallons transferred.

Either way, it would reduce the amount of gray water to be disposed of, and save on using fresh water from your holding tanks.

Good point about the detergents counteracting the break up of "black matter." Although, the boondockers swear by using and collecting the gray. I don't have enough experience to say either way.

It certainly doesn't sound very complicated to implement. I'm sure we will get additional input from more experienced RV'ers and technical people!