Fuel tank for black water

bluebird90 · 03-22-2011, 11:51 PM

I'm in the process of doing a bus conversion, What are your thouhgts on using an old steel fuel tank for black and gray water? I have access to several size tanks. thinking of having just one tank for both. any ideas on size? we will be spending no more than 2 days away from full hookups. The nice thing about using a fuel tank is it will be an easy bolt up to the frame.

fireman · 03-23-2011, 09:45 AM

100 to 150 gal tank will do fine

madpsalmer · 03-23-2011, 11:55 AM

Thats a great idea I have thought of this myself. Where can I get tanks like you have with brackets?

lornaschinske · 03-23-2011, 11:55 AM

Quote:

Originally Posted by bluebird90

... thinking of having just one tank for both. any ideas on size? we will be spending no more than 2 days away from full hookups...

Tankage size depends on your water usage. We have 18 gal tanks (1 black, 1 grey) in the Class C. That would be absolute minimum to me for two (fresh tank is 21 gal). Usually the waste tanks are double (plus a few gallons extra) of your fresh water. I would suggest that you use separate tanks.

WHY????

When you dump your tanks, it is standard practice to dump your black tank first, then use your grey tank to rinse out remnants of the black tank from the sewer hose when dumping at a dump station. Then you use the water hose at the dump station to run some fresh water down the sewer hose so that it's semi-clean of debris before you store your hose. Please note that this water is POTABLE WATER (drinking water) and do not allow the water hose to touch the sewer hose in any way. You would use this same hose bibb to fill your fresh tanks (which is why you disinfect the hose bibb and use your own hose to fill your fresh tanks... see "how to dump" link below).

When parked in a campground on full hookups, long-termers/full-timers usually leave the grey tank open all the time. But you MUST keep the black tank valves closed or you will get the dreaded "Pyramid of Doom". Some folks will close the grey tank to retain some water shortly before dumping their black tank so that they can rinse out the sewer hose and don't have piles off poo and TP sitting in the sewer hose. Unless you "went" a few hours before dumping your tank, it should have dissolved and you shouldn't have anything but small bit... which can stick up thing. But grey water is pretty stinky, sometimes worse than the black tank. I like to wash dishes or take a shower after dumping the black tank. The water hasn't been sitting getting yukky. But that's my personal preference... and I would forget either to close the grey valves or to open them back.

read http://www.skoolie.net/forum/viewtop...it=dump#p71355 "how to dump"

bluebird90 · 03-23-2011, 03:11 PM

Thanks for the input. I'm thinking of using the round tanks off a medium duty truck. I have one round thats about 40 gal.
If you go to a truck junkyard, you can get tanks, saddles and all for fairly cheap. The benefit of round tanks it the debris flows to the center and out.

lornaschinske · 03-23-2011, 03:26 PM

Quote:

Originally Posted by Iceni John

... how would you know when it's getting full (apart from peering down the loo)?

You listen for the splash when you flush! (Seriously)

Quote:

Originally Posted by Iceni John

...Re-using and re-purposing things is always good, especialy if it saves money!

We are all recycling... perfectly good school buses into RVs!

Roachhill · 03-23-2011, 05:51 PM

Aren't you concerned about the acidic water eating through the steel from the inside out. I have no experience in the matter but I know the manure digester at the methane plant has a terrible problem with the acid from the poo eating through everything metal. Just a thought.

sportyrick · 03-23-2011, 09:09 PM

sewage makes a sulfuric acid that eats everything but plastic, brass, copper and gold so unless you keep your steel tank sparkling clean it will be full of holes in no time. My brother used to vacuum out the sewers and we were all surprised how much stuff you find down there, lots of gold too. sportyrick

gseufzer · 03-23-2011, 09:38 PM

A novel idea but dont waste your time. if the tank stayed full and never got fresh air you would be ok but chances are you will eventually get some pc of metal different from the tank and the dissimilar metals will react with the air and acids and soon it will have eaten through.

bluebird90 · 03-23-2011, 10:05 PM

What about coating the inside of the tank with that stuff they use for fuel tanks? or that spray on bedliner stuff?

Steve · 03-24-2011, 10:05 AM

There is actual products for sale for sealing tanks. They are for old rusty tanks in classic cars that seals them and keeps the gas from rusting them anymore. Look up Gas Tank Sealer. The coating is probably resistant to sewage.

gseufzer · 04-13-2011, 09:25 PM

the sealer would help the problem of electrolysis . as for the bedliner idea, also would help. I would contact the manufacturers of these products and voice your concerns to them. they will be happy to help since they are always looking to further there products uses, its just good business. good luck let us all know there answer

kotflb · 04-14-2011, 01:30 AM

Quote:

sewage makes a sulfuric acid that eats everything but plastic, brass, copper and gold so unless you keep your steel tank sparkling clean it will be full of holes in no time. My brother used to vacuum out the sewers and we were all surprised how much stuff you find down there, lots of gold too. sportyrick

Couldn't you pour in a box of Arm & Hammer after each dumping to neutralize the acid formation and help hold the odor down? I know it works great for spilled battery acid, and I don't believe our bodies are producing anything that strong.

Jarlaxle · 04-14-2011, 07:21 PM

Quote:

Originally Posted by bluebird90

Thanks for the input. I'm thinking of using the round tanks off a medium duty truck. I have one round thats about 40 gal.
If you go to a truck junkyard, you can get tanks, saddles and all for fairly cheap. The benefit of round tanks it the debris flows to the center and out.

Many trucks use oval or rectangualr tanks now...the Freightliner I drive has a pair of rectangular 50-gallon fuel tanks. I think FL started using them around 2000.

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