Carl Herd, senior maintenance worker for the City of Lawrence, mixes piles of yard waste at the city’s Wood Recovery and Composting Facility, 1420 E. 11th St. City trash trucks pick up yard waste throughout Lawrence and unload it at the composting facility where the mix of grass, leaves and small tree branches is left to decompose and later be used for compost.

Those containers of grass, leaves and small branches that homeowners put on their curbside each Monday morning add up to big savings and richer yards.

In 2008, 11,244 tons of residential yard waste was picked up and used in the city’s composting program. That amount saved $215,000 in landfill costs.

Cassandra Ford, waste reduction specialist on composting for the City of Lawrence, said the yard waste program was started in 1993 when the city realized that about 30 percent of what was going into the landfill was yard waste.

“That’s a huge chunk that can be diverted out and essentially recycled,” she said. “There’s no reason to send it to the landfill when we can do something else with it.”

The city collects the yard waste between March and December. Spring and fall, of course, is when the program peaks. In April, 11,090 households participated in the program by leaving 1,013 tons of yard waste at the curbside.

Ford said most residents complied with the rules. Among them are putting the yard waste only in carts, cans, or compostable bags. People also need to keep trash out.

“We get a lot of people who hide trash in the bags underneath the yard waste and that causes problems and causes contamination in the compost,” she said.

City employees encourage residents to put woody debris in a can or container and to not use plastic or metal twine to bundle it.

Once collected, the city trucks dump it in a row on an 8-acre asphalt pad at 1420 E. 11th St. Then Carl Herd, a senior maintenance worker with the city of Lawrence, uses a front-end loader to mix the green grasses with the brown leaves and woody debris for a good nitrogen-carbon mix. Once the items are mixed, Herd unloads the material in a gigantic tub grinder. The grinder then spits it out and into rows for composting.

The compost piles need air and moisture, so Herd will turn it a couple of times. The material also goes through a screener to eliminate larger debris that may take longer to decompose.

“The more compost you have, the more heat you can build up, and the faster it’s going to compost,” Ford said.

These piles compost in four months, while a backyard bin takes between nine months and one year.

The city has a three-day compost sale in the fall and spring when area residents can get a truckload for $10. If they load it themselves, it’s free. This spring, 1,510 vehicles picked up 1,746 tons.

“There’s a lot of people getting benefit from it,” Ford said.

The fall sale will be from 8 a.m. to 3 p.m. Sept. 24-25, and from 8 a.m. to 4 p.m. Sept. 26 — unless they run out sooner.