An effort to get Portland-area residents to recycle more carefully by grading their curbside bins with green, yellow and red tags has helped remove contamination from the recycling stream and saved taxpayers thousands of dollars.

Last summer, interns at ecomaine, the municipally owned regional solid waste company in Portland, spread out across neighborhoods in four communities every week and graded residents on how much nonrecyclable trash – referred to as contamination – they had mixed in with legitimate recyclables.

The program was part of ecomaine’s effort to improve its recyclables’ quality as it weathers a prolonged downturn that has increased recycling costs for taxpayers and municipal waste companies nationwide.

The project succeed in changing people’s behavior, ecomaine spokesman Matt Grondin said. About 4,200 households in Falmouth, Scarborough, Windham and South Portland created an average of 5 percent contamination reduction and $4,000 in municipal savings across the four communities because of the grading exercise, he said.

The top five contaminant categories were plastic bags, polystyrene foam, napkins and paper towels, bubble mailers and hoses, cords and other lines that can tangle sorting machines.

“To clean up the contamination in the recycling stream, that leads to better marketability to the product, that leads to a better bottom line not just for ecomaine, but for our municipalities,” Grondin said.

Ecomaine is owned by 20 southern Maine cities and towns, and it takes trash and recycling from another 29 communities. It operates a recycling depot and waste-to-energy incinerator in Portland.

Interns spent several weeks inspecting recycling bins in the four communities by leaving colored tags on each lid. A green tag meant the recycling was good to pick up, yellow meant there were some inappropriate items in it, and red meant it was too contaminated to collect.

Overall, interns only tagged a few bins with red, but saw big gains in converting people who were nearly there into good recyclers. In the first week in Falmouth, only one-third of the bins were approved by interns. By week four, more than half were getting green tags. Scarborough residents improved from just over half getting green tags to 84 percent in the eighth week.

Results were so promising in South Portland, Windham and Falmouth that interns switched to new routes about halfway through, hoping to make a higher overall impact, Grondin said. Resident reaction to the program was “overwhelmingly positive,” he added.

“There were some questions at first, but the interns did a good job about addressing safety and privacy,” Grondin said. “At the end we had a lot of people comparing with neighbors, vying for that green ticket.”

The exercise wasn’t just a PR move – recycling has cost towns and cities dearly in the two years since China banned imports of heavily contaminated materials. That ban left companies such as ecomaine without major markets for some of their products such as mixed paper. While the company makes money on most of the recyclables it processes, it has to pay $21 a ton to remove the mixture of mailing, printer, glossy, packaging and other paper that accounted for nearly 40 percent of its entire annual recycling tonnage last fiscal year.

While some towns and cities in the U.S. have cut back their recycling programs, ecomaine has continued accepting all recyclable materials, although in 2018 it announced penalties on heavily contaminated loads.

If a load is at least one-third contaminated with nonrecyclable materials, there isn’t enough manpower or equipment to sort it down to a level that it can be sold on the market, ecomaine CEO Kevin Roche said. In the past 18 months, the overall contamination rate has been cut in half, to about 9 percent, Roche said.

“That’s why we need the public to always question, ‘Which bin can I put it in?’ because there is only so much we can do to clean up the material,” he said.

This is one of the longest market downturns in Roche’s 30-year career in the solid waste business, but he expects it to turn around at some point. New mill capacity, including Nine Dragons Paper in Rumford, will come online soon and create a market for low-value material such as mixed paper, he estimates.

In the meantime, improving recycling quality will help keep costs down and material out of landfills.

“There is no waste management strategy that has been more successful than recycling in diverting material away from landfills,” Roche said. “Although, yes, recycling is more costly today than it has been for a long time, if you look over it for the last few decades, it has served our communities very well.”