As Hilliard residents, we are fortunate to have recycling that includes a weekly, single-stream, curbside-pickup program. "Single stream" means we don't have to separate the recyclables: Residents just place items in the big blue containers for convenient pickup at the curb.

Hilliard Environmental Sustainability Commission members recently took a tour of Rumpke's recycling center in Columbus and learned what happens to recycling after it is picked up, as well as what can and can't be recycled.

On average, Rumpke sorts through 60,000 pounds of "stuff" every hour. This equates to 900 million pounds annually. All central Ohio recyclable materials are deposited here, regardless of the pickup company.

Vehicles dump the materials on Rumpke's floor and separation begins.

Forklifts with huge grabber tongs move the material to large conveyor belts,where first cardboard and then paper float atop spinning disks while containers drop to a separate belt. Plastic bottles and cartons get sorted with infrared lights and air jets. Glass is broken, sifted and then cleaned using air bursts. Overhead magnets lift and remove steel cans, and electromagnets repel aluminum cans to another belt. The different streams get baled and shipped to manufacturers, who reuse the material.

However, throughout the process, a lot of workers pull out materials that cannot be recycled. The machinery is advanced, but people still are needed at multiple places along the conveyors.

Why aren't all materials recyclable?

There are three primary reasons: safety risks to the employees who work at the facility, machine damage within the plant or simply no end user exists for the material.

Syringes, corrosives, explosives and other materials can injure employees. Plastic grocery bags, old extension cords, scarves and similar items can wrap around the machinery, causing downtime. (Clean and intact plastic grocery bags can be taken to most grocery stores, which return them to their manufacturers to be reused.) And there simply isn't a market for such "recyclables" as old wood, egg cartons (yeah, that surprised us, as well), yogurt cups and plastic clamshell containers.

Some specific examples of products to exclude form recycling include: butter tubs, buckets, metal hangers, metal pots and pans, light bulbs, drinking glasses, window glass, hazardous and flammable materials, medical equipment, wood, yard waste, clothing, rubber hoses, rope, electronics, Styrofoam, car batteries, paper-based photographs and tissue paper.

What can we recycle? Items include:

•Paper, magazines, newspaper and cardboard. Some helpful tips: It's helpful to flatten cardboard, and glossy paper is accepted, but no paper cups or napkins.

•Plastic bottles and jugs. Lids and labels are OK, but not cups, tubs, yogurt cups and clamshell containers.

Basically, any plastic container with a neck is recyclable, and it is helpful to flatten the container and replace the lid to prevent rolling throughout the plant.

•Aluminum and steel cans with labels.

•Cartons and lined boxes. Keep the lids on and labels are fine, but it is helpful to rinse them.

•Glass bottles and jars. All colors are accepted.

The Rumpke facility truly is a marvel of modern technology and is open to tours by appointment. Visit rumpke.com for information.

Melissa Muth is a member of the Hilliard Environmental Sustainability Commission.