Cleaning a very dirty painted shell and bottom surface of storage tank

[Syahar1975]

Dear experts,

After discharging the hydrotest water out from our Demineralized Tank, we found that the internal surface of tank bottom and shell are very much dirty. See the attached photos. I am seeking an advise if there is a chemical could be used to clean accordingly.

The internal surface has been coated by Phenolic Epoxy Interline 850. Total DFT 250 micron.

Thanks.

Syah

 

[Compositepro]

It looks like sediment. That has to be washed out with a hose or pressure washer and a vacuum.

 

[racookpe1978]

As above, start with the pressure hose and vacuum.
Then - with a very light pressure washer, "wash" the walls (don't blast them with high pressure!). Vacuum out the residue again. Wipe down ALL surfaces (including those rust spots!) AND CLEAN, remove the rust and bad paint to bare metal. Recoat.