The mid-Atlantic Garbage Platform

Two hundred years of consumerism and failed attempts to clean up the oceans have resulted in the garbage zone, a fifty mile wide patch of floating detritus in the center of the Atlantic ocean.

Background
Before the money ran out, the European-American initiative to clean up the Atlantic only managed to collect it into a concentrated patch.

Platform Society
Thousands of people from all over the world have come together and built a floating hulk out of the refuse, which they use as a platform to harvest garbage to sell. Food is taken from improvised algae tanks, as the water is too polluted to fish. The platform is a home to thousands of political prisoners and those who have nowhere else to go. By manipulating the arrays on the periphery of the garbage zone, its inhabitants have the ability to move the garbage patch around the ocean to enable them to collect more valuable garbage.

Reddit user: Noddybear.