Airplanes use recirculating toilets. When you first get on a cleaned plane
the toilet water is deep blue. By the end of a cross-country trip with a
load of passengers the color changes - to a medium bluegreen color. They
use macerator pumps internally as part of the tank itself so they are able
to do this. You could do something very similar with your Airstream. All
it would take is a bit of planning. I would not want to use the gray
water - because - that gray water would be taking space inside the toilet
tank and that would severely cut down on your capacity.
You could capture the gray water and then pump it into the toilet which is
then dumped elsewhere, that would work if the black tank capacity had the
room to spare. I don't think it does unless you are camping as a single
person or a childless couple, childless friends/partners, whatever. Don't
want to miss anyone! ;)))
Tom
WBCCI 5303