Usually Alkaline batteries can be safely disposed off in the normal garbage bins without causing an environmental hazards or damage to the environment. That is because a lot of the batteries manufacturing companies had opted to create batteries that virtually uses no mercury at all in its content. They use other common metals such as steel, zinc or manganese which are not harmful to the environment. Alternatively you can also go to your local recycling places where you can hand over your batteries to them for faster disposal. However, be sure not to group together large number of batteries because batteries though dead are technically not fully dead, and then these group of supposedly dead batteries come together, they could come live and create some sort of fire hazards.