I am installing a central grey water tank for sink and shower drainage in my
sailboat. The galley sink also has a garbage disposal. The question has come
up as to what type of discharge pump would best fit this application. I
would prefer to use a centrifical, but I suspect impeller fouling as well as
the slurry from the garbage disposal could be an issue. I think that I may
be locked into the use of a diaphram pump and I hate the sound. All opinions
and experiences are welcome.
Steve

I am using a macerator pump on my grey water sump but a garbage disposer
is going to cause a major dibris problem in the sump unless you are very
carefull in its design and the layout of the sink drain line. Disposal
output should not be allowed to stand at all.

Steve Lusardi wrote:
I am installing a central grey water tank for sink and shower drainage in my
sailboat. The galley sink also has a garbage disposal. The question has come
up as to what type of discharge pump would best fit this application. I
would prefer to use a centrifical, but I suspect impeller fouling as well as
the slurry from the garbage disposal could be an issue. I think that I may
be locked into the use of a diaphram pump and I hate the sound. All opinions
and experiences are welcome.
Steve



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Steve Lusardi wrote:
I am installing a central grey water tank for sink and shower drainage in my
sailboat. The galley sink also has a garbage disposal.

The garbage disposal is gonna create all kinds of problems for
you...'cuz while gray WATER (galley, bath and shower water) can be
legally be discharged directly overboard in all coastal waters (except
in some areas of the FL Keys National Marine Sanctuary), galley WASTE
may not be. So if galley waste goes into your gray water tank via a
garbage disposal, you won't be able to dump the tank inside the "3 mile
limit" in any country that has similar restrictions...only at sea beyond
3 miles.

I've never actually examined the output from a garbage disposal to see
how finely it grinds up waste, but no matter how fine it is, bits of
food aren't gonna dissolve anywhere near as quickly as toilet waste, so
any pump you install is likely to become clogged, whether it's an
impeller or a diaphragm. Megayachts often have disposals, but they also
have very sophisticated waste treatment systems that include filters
(that must be cleaned regularly) to keep stuff out of the pumps.

So IMO, you'd be wise to reconsider having a disposal...it's gonna cause
you many more problems than it will solve.

And btw, a gray water tank produces the same odor control issues as
waste tanks, and need to be similarly maintained. Depending on the size
of your gray water AND waste tanks, you might want to consider
installing an aeration system in 'em.

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://www.seaworthy.com/html/get_ri...oat_odors.html

Thanks to both Peggie and Glenn. I will not connect the disposal to the grey
water tank. I will connect it to a separate thru-hull directly and use it
according to local rules. This is possible because the galley has a dual
sink. I would think that is acceptable.
Steve

"Steve Lusardi" wrote in message
...
I am installing a central grey water tank for sink and shower drainage in
my
sailboat. The galley sink also has a garbage disposal. The question has
come
up as to what type of discharge pump would best fit this application. I
would prefer to use a centrifical, but I suspect impeller fouling as well
as
the slurry from the garbage disposal could be an issue. I think that I may
be locked into the use of a diaphram pump and I hate the sound. All
opinions
and experiences are welcome.
Steve