On Monday, Casella Waste Systems reopened a renovated, single-stream recycling center, in Charlestown, Mass., to serve Boston customers.

Rutland, Vt.-based Casella refers to the single stream recycling technology used at the Charlestown facility as Zero-Sort. All recyclable materials arrive at the center completely unsorted. Eight optical sorters, seven disk screens and three magnets process the material, yielding 45 tons of sorted recyclables per hour (750 tons per day).

The old Charlestown facility was retrofitted beginning in Sept. 2008. A similar Casella facility is located in Auburn, Mass. to serve the central region.

"Casella undertook this multi-million dollar renovation because we believe single-stream recycling is the wave of the future," said John Casella, president and CEO of Casella Waste Systems. "By going to a Zero-Sort process, municipalities can save money on trash disposal while increasing the rate of recycling among residents and local businesses."