The Avac is New York’s only pneumatic garbage-collection system. Designed in the late nineteen-sixties to service Roosevelt Island’s housing developments, the system runs under all the island’s high-rises. When people throw their garbage down the trash chutes, it piles up for several hours, until a trapdoor opens, sucking the waste into a big underground pipe. Then a complex system of air valves propels the garbage through the pipe at speeds of up to sixty miles per hour. When the trash resurfaces at the Avac center, a squat building at the northern tip of the island, it is dumped into two silo-shaped cyclones, where it is spun like cotton candy and then whooshed down chutes into huge containers

— http://www.newyorker.com/archive/2003/11/17/031117ta_talk_taylor