From a marketing standpoint, the new system’s computer programming allows for custom-tailored processing of plastics to meet end-buyer requirements if requested. This, coupled with the increase in material volume has resulted in greater marketing flexibility. The operator of the MRF (City Carting of Westchester) also serves as the marketing agent for the processed recyclables. Under this arrangement, City Carting can take advantage of their resources in order to gain access to a wider variety of end-buyers willing to pay top dollar for Westchester County’s recyclables. As a result, the monthly revenue generated at Westchester’s MRF hit an all-time high of $971,000 in September, 2011. By contractual agreement between the County and the operator of the MRF, the County receives 80% of the total revenue while the operator acting as the marketing agent for the processed recyclables receives 20%. This agreement provides the marketing agent with an incentive to maintain markets that consistently return the highest possible revenue.

About the equipment: the system is computerized with touch screens located at several locations for operating, monitoring, system adjusting (if needed) along with pull cords and e-stops for worker safety. Commingled recyclables are processed using a combination of conveyors, pneumatic vacuums, magnetic and non-magnetic separators, glass scalping screens, compressed air blowers and optical sorters.

Commingled material is conveyed into the system by a pair of in-feed conveyors (a horizontal conveyor leading into an ascending conveyor) which leads to a presort station. A metering drum suspended above the ascending in-feed conveyor protects the in-feed conveyor from load excesses (1,500 PSI). When loads exceed this 1,500 PSI value, the drum’s hydraulic unit will engage, lifting the drum so as to avoid damage to the conveyor. Once the commingled recyclables have been delivered up to the presort station, 6 sorters pull out contaminants and should the recyclables be encapsulated in plastic bags, de-bag the recyclables and feed the film plastic into overhanging vacuum chutes which are then transferred through a ducting network directly to an IPS Film Baler.

From there, the ferrous metals are extracted from the commingled stream by a drum magnet separator which delivers the ferrous onto a conveyor belt for discharge into a holding silo until enough material to constitute a “bale” has accumulated. The remaining glass, plastic and aluminum are then passed across a glass breaker-sculpting screen system. This 3-tiered component breaks the glass material into small fractions, separating these small fraction materials from the remaining larger containers (i.e. aluminum and plastics). The glass is conveyed to holding bins located at the rear of the MRF for transport to market. The aluminum is separated from the plastics by an eddy current separator and conveyed via an aluminum silo blower to a dedicated aluminum hopper.

The plastics are then introduced to multi-stage optical sort system. Once the sensors identify a specific resin that the computer was programmed to separate, it triggers an air jet system to positively eject the wanted material into holding bins. All plastics that are not ejected are then transferred back to the inbound material stream for a “second pass” through the system. In addition, aluminum that is not captured by the eddy current separator during the first pass- through get transferred onto a “2nd pass” conveyor belt (along with any trash residue) and removed by sorters manning that conveyor belt.

As a result, Westchester County’s MRF has seen commingled residue tonnage reduced by over 50 percent since the installation of this system was completed in July, 2011.

For more information on Westchester County’s MRF and programs visit www.westchestergov.com/recycle.