I have no idea of the answer to your question about disposing of bromine but I did find that "approximately 556,000 tonnes [of bromine] (worth around US $2.5 billion) were produced in 2007 worldwide" (from Wikipedia's "bromine" article). If you have over 50,000 tons of bromine, that would seem to be worth a lot of money (~$250 million!!!). Why not sell it?
Neutralize spilled bromine in laboratories and similar locations with a solution of sodium thiosulfate and water. Mop up the neutralized bromine with mops and sponges and repeat the entire process twice more.
Add one ounce of sodium thiosulfate crystals directly to your pool in front of your return line. Your pool’s return line is usually at the shallow end of your pool and leads to your skimmer. This amount of sodium thiosulfate will neutralize one part per million of bromine in 10, gallons of water.
Repeat the sodium thiosulfate treatment of your swimming pool at intervals of 1 hour until you are satisfied with your bromine levels.
Add 1/2 teaspoon of sodium thiosulfate crystals directly to your spa with the circulation system running. Wait 1 hour before repeating the treatment as needed.
off-course the above material exist in the following link:.