View Full Version : Water contamination in very large diesel storage tank - what to do?

Andy Rylance
31st Aug 2008, 21:48
Walking down the local lane I was speaking to the farmer who had problems. His 900 litre diesel tank has just had a refill but somehow water has got into it and now the fuel is contaminated.

So the question is how can you get water out of a water/diesel mix chemically or what would be the best way - the water isn't huge amounts but needs to be removed and the farmer does not have a 900 litre second tank to decant things to - and even then how would you make sure you just get the diesel?

what would people advise?!

31st Aug 2008, 22:20
Don't talk to farmers.

31st Aug 2008, 22:45
surely it has a water drain?

if not, maybe he'll have to (god forbid) PAY someone to come in with a 1000l tanker, decant the fuel off the top, and suck the water out of the bottom. 900l is not really that much - only 5 40gal drums.

31st Aug 2008, 22:49
Mr Funnel, the largest one they make.

Loose rivets
31st Aug 2008, 22:54
why can't you pump the water out of the bottom with a long pipe:confused:

Water misted into the fuel might be caught with a chamois leather over a BIG funnel used to work for certain flyers of Tiger Moths.

Then there are water trap in line filters.

John Hill
31st Aug 2008, 23:02
There are several solutions....

Push a hose into the tank directed so that it goes to the lowest point of the tank then siphon out a few gallons which having been drawn from the lowest post of the tank will include most of the water.

Fit one of those glass jar filters on the outlet line which will collect the water and give a visible indicator.

Add alcohol to the tank which will cause the water to mix with the diesel oil. Alcohol, ethonol, methonol any of 'ol' will do the trick, or so I have been told.

.........best of all, do all three!

Andy Rylance
31st Aug 2008, 23:29
I looked at the tank it had no water take off from what I could see. A lockable take off cap coming out lower down on the tank, and the filling intake at the top, but no visible specific water take off.

31st Aug 2008, 23:49
But, Shirley, if you leave it to settle, then draw off from the bottom (I presume that that is how the tank is emptied) then the water will flow first. When the diesel starts to run, it can be run into a container, allowed to settle, and then the diesel syphoned off the top. Clear containers will help, of course. I presume that the farmer's fuel is red (rebated) diesel. The water should be clear (though I'm uncertain about that).

A lockable take off cap coming out lower down on the tank,Why is the take-off not at the bottom? Is this to ensure that any water will settle below the take-off?
If the water contamination is already up to the level of the draw-off (so mixed diesel and water is coming out) then see above (allow mixture to settle and separate by siphoning). Does the take-off cap just run free, or does it need a pump to transfer it into the recipient vehicle? I can't believe that the farmer uses churns for this. If he does then he'll have to let it settle (as above).

Edited to add:-
United Kingdom regulations state that all fuel-dispensing tanks must be bunded.
That means double-skinned or contained in a surround so that leakages are contained.

1st Sep 2008, 00:12
Chock the tank

1) Check that tank base is sound

2) Use scaffold board (or similar) to spread point load and 2 x3" fence stabs to lever tank to allow insertion of similar stab to chock tank thus allowing water to settle away from tank outlet

3) Settle tank and recommission

4) Either try to siphon off collected water or when tank dry/empty unchock tank and drain residue

Beware of a Winter condtions


If Steel tank, as soon as practical check for corrosion

PZU - OUT of AFRICA (retired)

1st Sep 2008, 00:23
Surely it should be possible to fit a sediment trap with isolator taps to the outlet and, as the tank is progressively drained, remove the water that gathers in the trap and discard it

1st Sep 2008, 02:06
The big problem is how long the water has been there and whether the tank is about to rust through and start leaking diesel which will please the environmental authorities no end:uhoh:

Fuel Tank Maintenance (http://www.schaefferoil.com/markets_fuelStorage.html)

1st Sep 2008, 02:47
Racor (http://www.usdieselparts.com/racor.cfm) filters are used in a variety of applications.

1st Sep 2008, 02:56
Mr. John Hill.
Sir, shame on you sir, shame!
No one, sir, should be allowed to put up a tent, let alone take up residence in this country without knowing that the solution to ANY problem on a farm begins with a length of no.8 wire and a gumboot. (This silly speeling checker doesn't know what a gumboot is.!!)

As for this English farmer chappy, if he still hasn't solved his problem after six hours......... I don't know what farming's coming to.

1st Sep 2008, 03:03
1. Open drain on tank
2. Repair to smoko shed for cup of tea
3. Rinse tank with clean diesel
4. Refill tank with diesel
5. Claim insurance for 900 litres of spilled juice
6. Don't smoke (or try to grow anything) in immediate vicinity of tank for 10,000 years.

John Hill
1st Sep 2008, 05:28
RiscOS, are you sure Helen is OK with you blabbering national secrets on this international forum?:eek:

1st Sep 2008, 07:08
Andy Rylance,
Ignore those other silly antipodean replies, this is the real oil so to speak
What is required is a milk separator, you know the ones that separate the milk from the cream. Pass the contaminated fuel through the separator, and the fuel will come out the cream spout, and the water out the milk one.
With a bit of ingenuity the mix could be passed through the separator on a continuous basis until the water stops flowing.
If the farm concerned is a diary farm, then everything required should be on site.The only thing to watch is that you have everything ready to go immediately after milking is finished so that the operation can be finished before the next milking is due. Bovine ladies don't like being kept waiting.


green granite
1st Sep 2008, 08:41
1. Open drain on tank
2. Repair to smoko shed for cup of tea
3. Rinse tank with clean diesel
4. Refill tank with diesel
5. Claim insurance for 900 litres of spilled juice
6. Don't smoke (or try to grow anything) in immediate vicinity of tank for 10,000 years.

You missed a bit Wolfie :E

7. Pay 50,000 fine to the environmental police.

1st Sep 2008, 09:55
:rolleyes: Usual quality advice on here I see :rolleyes:

A few key pointers:

Modern gasoils have extremely poor water shedding problems due to the presence of various additives. It is generally not possible to simply allow the water to "drop out" - enough will stay in suspension to keep the fuel "hazy".

Water contamination in Gasoil will almost certainly result in the development of bacterial contamination over a fairly short space of time. (This sh1t will block fuel filters.)

Additives can be obtained to promote water dropout and to stop bacterial activity (Google Baker Petrolite for a manufacturer).

Alcohol addition will not work (and will render the diesel off spec :=)

PS 900 litres is not "a very large tank" - the largest gasoil tank with water contamination I've dealt with (so far) is 100,000 tons ;)

4th Sep 2008, 02:08
I am surprised that the farmer even mentioned it. Water contamination in diesel is not uncommon and can be solved by one or a combination of the following:
a) tell the supply company that they delivered water and diesel and ask them to "wash" it and make good the shortfall;
b) if the tank set-up has a decent water-separator and pump plumbed in, use it and divert the pumped diesel back to the tank after it has been through the separator. NB, drain water from separator frequently;
c) get a fuel rated pump (available via many motorfacters) complete with long dangley hose and feed it to the bottom of the tank (with stick if required), then pump out until fresh diesel is seen. Retain the bleed off and claim extra diesel or refund from supply co.;
d) if he has got plenty of money and too many other things to do, call a fuel washing company;
e) treat fuel with medicine as described in post above;
f) keep tank brimmed to prevent condense contaminating diesel.
g) change supply co.
The tank would be considered as modest in size. Tanks for domestic central heating plus pool heating are usually 2 x 1,900l, and for boats up to about 12m, 2 x 500l to 2 x 1000l, so no one should have any problem with just a single 900l. If he meant to say 9,000l then b) and c) above do not apply.

4th Sep 2008, 13:23
Wait a minute, you said he was a farmer. Can't he just get a grant from the government to clean it?

...or better still, a grant to NOT clean it?

4th Sep 2008, 14:56
Simple really! Light a fire beneath the tank, open the refill cap, bring to a boil and let water boil off. Voila!! Distilled diesel!:}


Ok, I'll get me coat

Andy Rylance
4th Sep 2008, 17:26
Ah thank you all so much for the advice. Some of it of dubious merit. :) It appears it may be a fuel delivery problem. If in doubt ask other farmers. I think Mr delivery person is going to come around and do something.... May the "come on baby light my fire" sort of do something...:rolleyes: then perhaps not....

4th Sep 2008, 18:56
The alternative would be to freeze the contents of the tank (would the ice rise up to the surface?) then the diesel could be drawn off, leaving the (solidified) water behind.

4th Sep 2008, 20:51
You missed a bit Wolfie http://static.pprune.org/images/smilies/evil.gif

7. Pay 50,000 fine to the environmental police. Well actually, GG, he missed the step before that.

6A. Take out Mobile Phone, ring environmental police (aka Environment Agency) and tell them that you've just tipped 900 litres of oil on to the ground.

Steps 6A and & 7 can be missed out if you are short of 50,000.

4th Sep 2008, 22:03
Actually I wasn't intending on letting the Environazis in on this one, thus saving the 50,000 Pomgolian Currency Units (don't have a pound sign on this keyboard. There is a clever way of getting the computer to generate one, but I don't know what it is). In fact if we drain the tank via way of a judiciously applied .270 round, we can call it an accident.

You'd have to be careful with that freeze distillation method G-C, lest the diesel should turn into a big lump of wax :ooh:

John Hill
5th Sep 2008, 00:10
He could of course just get rid of those poncy green and yellow tractors and revert to something like his Daddy's Field Marshal
or even a nice blue Lanz with red wheels!


Would either be worried by a bit of water in the diesel?

5th Sep 2008, 02:36
The farmer may be screwed on this particular tank of diesel if he doesn't figure out a way to sump the water out of the bottom of the vessel. Fuel that sits too long develops microbe contamination which grows between the area where the fuel meets the water. One cheap way to prevent the contamination from entering his farm equipment is to buy a pump filter canister which can be attached to the hose at the point where the hose enters the tank. Those can be purchased at any farm machinery/hardware store. At least if he pumps out the contaminated fuel it will be filtered before entering his equipment.

5th Sep 2008, 05:59
the area where the fuel meets the water

Damn, that's just evocative, it's like that far-off upturned sawblade of jagged mountain peaks and misty wind-blown sea-spray, where the ocean meets the sky...or, in Zen, the state of Nen, to keep one's focus on the point where two surfaces meet.