Cleaning Underground Storage Tanks

Hi Zulkifeli, I am not aware of any system that can be used to clean the bottom sludge from a UGST unless there is manway access. You could try re-cycling product through the tank but this won't dislodge hard sediment, any hydraulic movement of product, gasoline etc' will also require to have serious "Anti-Static" protection.

You might consider posting your query to the Dangerous Goods-Hazmat Group at:

http://tech.groups.yahoo.com/group/DangerousGoods/

Best Wishes

Don in Melbourne AU

To get access to the inside of the tank you will have to uncouple the pipework at the lid and then remove the lid itself. There is a very real danger of explosion and/or asphyxiation with this type of work so don't take on this job unless you are prepared to work safely! It sounds like you will be doing a lot of tanks so invest in good safety equipment and insurance for your men and 3rd parties before you start. You will not be able to carry on sales in the vicinity of the open tank lid for obvious safety reasons. Removal of the sludge is a bucket and shovel process I'm afraid then you can use steam or high pressure water to clean the surfaces if you want this degree of finish. The cleaning process will generate static electricity!!!

First get yourself a good safety harness with a strong tripod at the surface so that you or your man can be hoisted to the surface if they lose consiousness. There are many stories of people going into tanks to rescue their companion only to suffer the same fate - there MUST always be at least one man on the surface with a man in the tank. This rule also applies to manhole chambers deeper than 1 metre, (my Company lost an engineer in a 1 metre manhole in the middle of a supermarket forecourt so be very aware of the dangers). If you can get hold of a personnal oxygen/gas detector this will give early warning of danger before you pass out from lack of oxygen, (www.draeger-safety.co.uk)

Men working inside the tank must wear breathing equipment - you cannot ever de-gass the tank completely and while it is being cleaned there will be a lot of gas and fumes. The sludge is carcinogenic so wear protective clothing and provide washing facilities and changes of clothing,( preferably made of material which doesn't create static electricity). To get good advice locally in Malaya go to a shipyard, (Singapore?) where they have to go into sealed tanks and voids regularly - they will help you I'm sure and may even provide some safety training

Other things to consider are: disposal of sludge and contaminated liquids and the condition of the tank structure itself. No point cleaning a tank which is rusted to the point of leaking - carry out a pressure test with nitrogen before starting the job and another on completion, (to test the integrity of the pipework after you reconnect it). It is essential to seal the lid or surface water can get into the tank and contaminate the contents.

This is unpleasant and dangerous work - get yourself well prepared and you could create a good profitable business and live to old age, get it wrong and you might die or have to stand up in court on a manslaughter charge!

Dear Tom,

Thank you for your advice.

Fyi, our company located in Malaysia. Our current core bussines is doing 3rd party testing off underground strorage tank & pipelines testing.

We using vacuum system for Underground Storage Tank testing (-pressure). All joint i.e. ventelation, filling pipe (put Microphone ) and Dip pipe (put microphone and water sensor) closed when testing time. For Pipeline, we using Nitrogent test ( We NOT put Nitrogent inside the pipe, but pressure the product at sylinder and take a reading avery 15 minutes after monitor mode and testing mode.

Many our clients is petrols station and Industrial site area.

At the same time, many client invite us to do the cleanning tank. In here many traditional mathod used (time,cos,space and stop operation).

I very happy from you explanation and i hope i can friend with you and discused any technical method for any project or proposal.

Regard.

Zulkifeli Bin Md Yunus
Executive Testing & Marketing : zulkifeli@transnoble.com

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