Converting Black Tank into a Grey Tank Overflow?

[PhrankinPhoenix]

I was just wondering (if anyone would like to humor me)....
If I removed the toilet (in any Wanderlodge) and replaced it with a
"composting toilet" (like....https://www.youtube.com/watch?v=_E2xOoNov9s ),

could the abandoned Black Tank then be used as a Grey Tank (overflow)
for longer periods (of dry camping) before dumping?????

In theory it seems like it could be done....
BUT, Can it be done?

What is your experience?
Do you think this could be done?

[al perna]

you also have sink water that goes to the black tank , but otherwise , sure . I have a friend with a compose head , seems to work for him

PS,

the lady with the vanhool, wow !!

[mikebulriss]

Hi Frank,

Composting toilet would be cool. In answer to your question, as Al just said remember that the black water tank kinda-sorta is a grey tank already as the sinks usually drain into that tank to provide enough water to purge the solids. So unless you are taking huge showers, which will deplete your fresh water supply rapidly, you should be fine. As a reference, on my 91 WB40, the factory specs say fresh water is 137 gallons and the grey and black water tanks are both spec'ed at 100 gallons. So in the end result when dry camping, you'll probably run out of fresh water first before you fill either tank. So tying the tanks together seems somewhat superfluous.

FWIW.

[PhrankinPhoenix]

"As a reference, on my 91 WB40, the factory specs say fresh water is 137 gallons
and the grey and black water tanks are both spec'ed at 100 gallons.
So in the end result when dry camping, you'll probably run out of fresh water first
before you fill either tank.
So tying the tanks together seems somewhat superfluous."

Thank you Al & Mike.
Mike, I like your logic here...a point well taken...but (just for chuckles)
you are forgetting about ALL the BEER!

[PhrankinPhoenix]

For The Record....

I Just found this YouTube video on
one more way to solve this challenge of
combining the 2 Holding Tanks...
https://www.youtube.com/watch?v=T1dXcBchbuQ
From: Gone with the Wynns

Aren't the internet and the RV'ing Community WONDERFUL!

[mpierce]

"As a reference, on my 91 WB40, the factory specs say fresh water is 137 gallons
and the grey and black water tanks are both spec'ed at 100 gallons.
So in the end result when dry camping, you'll probably run out of fresh water first
before you fill either tank.
So tying the tanks together seems somewhat superfluous."

Unless you have a portable bladder, and go and get water, and bring it back to the fresh water tank, then it would help out.

[davidbrady]

As another point of reference, in the Prevost converter world both Parliament and Liberty Coach have only one holding tank, both grey and black flow to the one tank. They have a grey water bypass in case you're in an environmentally friendly area which permits dumping of grey water to ground. Folks love this setup. The advantage is clear: you can use your tank to near 100% of capacity before pulling up roots to find a dump station. Frankly, I think the dual holding tank notion is an anachronism carried over from the days when it was largely permitted to freely dump grey to ground. Thoughts?

[al perna]

we have been living full time for 3 plus years . we spend approximately 8 days dry camping 9 times a year . what I find is as long as both tanks can handle all water on board, there has never been a reason for us to need the excess area of the black tank for water . You see , if I can get fresh water, I can dump grey water . In the rare cases where we have needed to dump and add water , there is always a campground around
I will also add ,8 days without fresh water or dumping ability, is long enough for us . When we attend Q , there is nothing wrong with driving 1 mile for fresh water and dumping every 5 days or so ..

[timetravelers]

We already have a combined tank, I've used it several times. All you do is to open the air valve for both tanks, without having a drain hose hooked up. The tanks flow thru the common connection at the drain.

Don't you always run gray water thru the connection when dumping to clean out system and put a little gray water in the bottom of the black tank?