Degassing an underground fueloil tank
Discussion
We have an old fueloil tank buried in the garden. I have to put in a soakaway and this tank is between it and the water collection point so has to be removed.
I have a friend with an eight ton digger in for the soakaway and was thinking about the possibilty of doing this myself.
There is an access plate visible with bolts all around it and about ten cm deep of fuel left in the tank. I'm going to pump out the fuel with an electric pump but then it's going to have to be "degassed" and cleaned out before we can cut it up and pull out the pieces.
Anybody ever tried this before by any chance?
I have a friend with an eight ton digger in for the soakaway and was thinking about the possibilty of doing this myself.
There is an access plate visible with bolts all around it and about ten cm deep of fuel left in the tank. I'm going to pump out the fuel with an electric pump but then it's going to have to be "degassed" and cleaned out before we can cut it up and pull out the pieces.
Anybody ever tried this before by any chance?

First of all - DON"T under any circumstances get in it. A major cause of deaths in industry is from people entering benign looking tanks and suffocating from gases or lack of oxygen. What usually happens then is that someone else gets in and dies trying to rescue them!
Best bet really if you're determined to do a DIY job is water. Problem with that is that you're going to potentially end up with 3,000l of oil tainted water to 'dispose of responsibly'.
A better bet would be to secure some Nitrogen which will be heavier than the fuel oil gas and purge out the fuel oil gas with that prior to cutting. And then just make your first cut a big-un and the tank is well ventilated for subsequent cuts. Don't forget though that N2 won't explode but will asphyxiate you very quickly so repeat again - still don't get in that tank!
If in doubt get someone who knows what they're doing round!
ANother tip is don't do it on a sunny day!
Best bet really if you're determined to do a DIY job is water. Problem with that is that you're going to potentially end up with 3,000l of oil tainted water to 'dispose of responsibly'.
A better bet would be to secure some Nitrogen which will be heavier than the fuel oil gas and purge out the fuel oil gas with that prior to cutting. And then just make your first cut a big-un and the tank is well ventilated for subsequent cuts. Don't forget though that N2 won't explode but will asphyxiate you very quickly so repeat again - still don't get in that tank!
If in doubt get someone who knows what they're doing round!
ANother tip is don't do it on a sunny day!
Edited by Olf on Wednesday 19th May 19:39
Please do not get in it! We did a confined spaces course and some 999 footage was shown of 2 guys nearly dieing doing a very similar task.
I have no idea what else to suggest, but this is a big no no! I take it if you have an old oil tank your in relatively remote parts, even bigger no no.
I have no idea what else to suggest, but this is a big no no! I take it if you have an old oil tank your in relatively remote parts, even bigger no no.
We come across there all the time - often when we're building houses on the site of a former filling station.
Prepare yourself for some BIG costs.
You can't just dig out/cut up the tank then bang a soakaway in, because even if you can remove the tank cleanly, the leakages/spillages over the years will almost certainly have contaminated the ground so if you put a soakaway in, you'll risk simply flushing the contamination into the aquifer, which, if it happens, will send the Enviroment Agency proper apes
t.
You've usually got to remove the tank according to a proper procedure, then take soil samples to determine extent and nature of contamination, then remove the contamination and cart it off to an approved tip for hazardous waste (which costs a fortune) and fill the hole with clean material.
Bottom line... DO NOT take the advice of DIY Joe Bodgits on a motoring forum (or myself, for that matter - I'm an Architect not an Engineer, so even I would leave it to the specialists). Line yourself up a second mortgage, then get a (geo environmental) specialist in to advise you.
Prepare yourself for some BIG costs.
You can't just dig out/cut up the tank then bang a soakaway in, because even if you can remove the tank cleanly, the leakages/spillages over the years will almost certainly have contaminated the ground so if you put a soakaway in, you'll risk simply flushing the contamination into the aquifer, which, if it happens, will send the Enviroment Agency proper apes
t. You've usually got to remove the tank according to a proper procedure, then take soil samples to determine extent and nature of contamination, then remove the contamination and cart it off to an approved tip for hazardous waste (which costs a fortune) and fill the hole with clean material.
Bottom line... DO NOT take the advice of DIY Joe Bodgits on a motoring forum (or myself, for that matter - I'm an Architect not an Engineer, so even I would leave it to the specialists). Line yourself up a second mortgage, then get a (geo environmental) specialist in to advise you.
I`ve cleaned a few sites up which have had large old underground tanks,to make any former industrial land clean / sellable the costs are quite onerous, surveys /contaminated land costs / specialist removal
However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
Pobolycwm said:
I`ve cleaned a few sites up which have had large old underground tanks,to make any former industrial land clean / sellable the costs are quite onerous, surveys /contaminated land costs / specialist removal
However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
sounds good.However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
Olf said:
Pobolycwm said:
I`ve cleaned a few sites up which have had large old underground tanks,to make any former industrial land clean / sellable the costs are quite onerous, surveys /contaminated land costs / specialist removal
However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
sounds good.However in your case if we assume it is a small domestic tank I think you could handle it yourself if your sensible,
As stated previously never enter the tank
Remove as much of the oil as possible, do not put an electric submersible pump into the tank, suck it out with a pipe dipped into the tank.
Lift the tank out with the digger
Drain the rest of the oil out of the tank
Make sure nobody can get into the tank, put a fixed mesh over the opening if possible
Leave the tank vented, if possible use forced ventilation ie duct blown air into the tank from an external fan until the tank is dry, may take a few weeks
When you`re sure it`s dried out spray the inside of the tank with water
Get a few foam extinguishers with capable operators in position, start to cut the tank up
Driller said:
Olf said:

eta:
...oh, and if you're trying to 'dry out' the tank as suggested, remember that while that will be reasonably effective for very light hydrocarbons like petrol, heavier fuel oil will take forever (literally) to evaporate.
Edited by Sam_68 on Friday 21st May 08:18
Sam_68 said:
Driller said:
Olf said:

eta:
...oh, and if you're trying to 'dry out' the tank as suggested, remember that while that will be reasonably effective for very light hydrocarbons like petrol, heavier fuel oil will take forever (literally) to evaporate.
Edited by Sam_68 on Friday 21st May 08:18
You could be right about the diesel tank taking ages to dry out, I thought a couple of weeks with forced ventilation would do it but maybe a couple of months required ?
Just leave the hulking great metal tank visible somewhere.
Pikeys will have it not bother.
I love the way PH posts can start off with the OP all optimitstic about getting useful advice on a seemingly surmountable issee only for someone to come along and explain the potential for a life changing, catastophic consequence.
Pikeys will have it not bother.
I love the way PH posts can start off with the OP all optimitstic about getting useful advice on a seemingly surmountable issee only for someone to come along and explain the potential for a life changing, catastophic consequence.
dave_s13 said:
Just leave the hulking great metal tank visible somewhere.
Pikeys will have it not bother.
I love the way PH posts can start off with the OP all optimitstic about getting useful advice on a seemingly surmountable issee only for someone to come along and explain the potential for a life changing, catastophic consequence.
It's the ultimate "ohhhh, you don't want to be doing it like that".Pikeys will have it not bother.
I love the way PH posts can start off with the OP all optimitstic about getting useful advice on a seemingly surmountable issee only for someone to come along and explain the potential for a life changing, catastophic consequence.
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