PROVIDENCE — The city is working to stop residents from putting trash in their recycling bins. The Department of Public Works has stepped up its enforcement by attaching red stickers to misused curbside recycling bins. The stickers temporarily seal the bin so offenders get the message.

The DPW also is issuing between 50 and 100 tickets with fines during twice-weekly bin inspections. “We’re not getting many complaints,” said Sheila Dormody, the city’s director of sustainability. Yet, the tickets haven’t been effective, Dormody admitted, as landlords often don’t receive them. A fist offense carries a $50 fine; $100 for a second ticket.

At its October meeting, the City Council will consider stricter penalties, such as issuing a lien on a property for unpaid fines.

Door-to-door canvassing by youth volunteers started three weeks ago, but it’s too early to see a trend, Dormody said. For eight weeks, a team of four to eight volunteers will be walking through neighborhoods on the night before curbside collection to encourage recycling.

The Environmental Justice League of Rhode Island, the organizer of the canvassing, is in need of volunteers with cars to help shuttle the canvassers. The volunteers offer recycling advice in Spanish and English, while handing out refrigerator magnets and recycling dos and don’ts cards. They also ask residents to commit to better recycling by signing a pledge card. The card is then mailed back to the residents several weeks later to remind them of their promise.

Four hundred pledge cards have been collected during the first two weeks of canvassing, according to Environmental Justice League executive director Amelia Rose. Some residents have been defensive when asked to improve their recycling, others say the trash bin is too small, she said. Most are receptive to the outreach. “Overall, it’s going pretty well,” Rose said.

A mass mailing about the “Big Green Can” recycling program goes to all city residents this month.

The state’s single-stream recycling system allows residents to mix all recyclables — paper, cardboard, plastic and glass — in a single 95-gallon bin. So far, the city’s recycling rate has improved from less than 15 percent to more than 20, according to officials. But problems have persisted with collection in South Providence and in Elmwood neighborhoods. Food, liquids and non-recyclable items are being added to the bins, contaminating truckloads of recycling. The loads are then sent to the Central Landfill in Johnston, resulting in added costs for the city.

The city also is slowly expanding curbside recycling for businesses. In its most recent waste-collection contract with Waste Management, the city received 200 slots for recycling pickup for businesses. Businesses pay $50 for the curbside tote and otherwise receives free collection. Typically, business recycling collection is contracted independently, as collection is mandated by the state — although most businesses don’t comply and there is little enforcement.

This new collection program targets clusters of businesses. Earlier this year, 20 businesses on Hope Street joined the service. Ten bins were allotted to the Providence Community Library system. The West Broadway neighborhood uses 19 bins. Washington Park and Broad Street businesses have also inquired about joining the program.