In my community, there are companies that collect anitreeze from repair shops for recycling/disposal. I called one of these companies and they had me take mine to one of their customers (a local mechanic shop) who agreed to take it.
I also contacted the county department of heatlh and human services, which in my case manages hazardous waste disposal. They referred me to a city department of public works, which is the department that manages waste and recycling. As it turns out, their fleet maintenance group also takes used antifreeze from county residents.
You might check with such organizations in your area to see whether or not they offer similar services. It's a pain to deal with this stuff. I had been storing about 10 gallons of used antifreeze in my garage before I found these places.