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Interior coating of a sewage storage tank with epoxy

Our company provides Commercial Diving and Portable Welding services. We will be repairing an Aluminum brown water storage tank in a ship. The bottom of the tank is also part of the ships hull. "All Aluminum" The Aluminum is in constant motion from natural expansion and contraction as well as the structural flexing of the ships hull. The repair and epoxy will be in direct contact with the sewage. Will the effects of septic action, Sulfuric Acid (H2SO4), Hydrogen Sulfide(H2S) and whatever caustics present cause breakdown and ultimate deterioration of an epoxy coating?
"We need information on the types of epoxies",it's adhesion qualities and expected longevity in this environment. My first thought was to use multi coatings of a Plasti-Dip product or similar product. I only scared off the manufactures technicians by asking direct questions on their products compatibility and resistance to sewage.
Hopefully you can answer this one. So far; I haven't found anyone who can answer these complex questions. Thank you in advance if you can help solve this problem.

DALE HARRIS
OWNER welding / commercial diving - PARKLAND, FLORIDA, USA
2007

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Have you tried contacting the original manufacturer to find out what a suitable repair would be to the product they applied as a liner to this tank? I would guess that the coating is a thermoplastic, so you will have to use heat (probably flame spray) to make the repair once you get ahold of the material.

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
2007