Bromine is rather expensive, very reactive and quite often needed. For these reasons you should avoid to dispose it. Please pass it to staff instead who can use the bromine. Purification by distillation is possible. Dispose in a separate bottle.
Bromine may be converted to bromide by a reducing agent. The resulting salt solution may be flushed down the drain. Often thiosulfate is recommended as a reducing agent but in this case sulfur precipitates quite often. Therefore it is better to use sulfite or hydrogen sulfite solutions which will give no precipitations. Since the reaction gives protons as a reaction product carefully prevent the mixture from becoming too acidic by adding sodium hydroxide solution. Otherwise unwanted sulfur dioxide gas may be developed.