Participants in Oak Park’s composting program discard their food scraps and yard waste into closable gray bins. WBEZ/Monica Eng

Once a week, Waste Management visits Oak Park residences to collect the scraps. WBEZ/Monica Eng

The medley of organic waste travels southwest to a composting facility in Romeoville, where it’s dumped in a large pile. WBEZ/Waste Management

A giant machine grinds up the waste, increasing the available surface area for microbes and providing an even distribution of air and moisture. WBEZ/Katherine Nagasawa

Senior District Manager for Waste Management Kurt Nebel looks out onto the quarry where the pulverized waste sits in windrows for 90 days. WBEZ/Katherine Nagasawa

“Turners” straddle the windrows weekly to aerate them and reduce the odor from waste gases. WBEZ/Katherine Nagasawa

After 90 days, the now odorless black compost is dumped into a screener that filters it and spews out fine mulch out the end. WBEZ/Katherine Nagasawa

Karen Rozmus, Director of Environmental Services for the Village of Oak Park, marvels at the finished compost returned to Oak Park twice a year. WBEZ/Monica Eng