Portland’s new recycling carts will solve some environmental problems, reduce city costs and result in a more positive experience for both residents of and visitors to the city.

As a solid waste researcher at the University of Southern Maine, I have studied many aspects of residential recycling and trash nationwide. Which containers are used to collect recycling has been found to be an influential factor. I have conducted numerous studies measuring the impact of container selection on recycling rates and litter production.

Two of these studies, conducted in 2015, were funded by the Maine Economic Improvement Fund and done in cooperation with the city of Portland and ecomaine. The first study hypothesized that Portland’s reliance on small recycling bins increased the amount of recyclable materials disposed of as trash; the second study quantified the amount and impact of litter created by open-top recycling bins.

The small (18-gallon) open-top recycling bins were chosen by Portland in 1999. They were a reasonable choice for a new curbside recycling collection program: They were easy to use and were the cheapest to purchase. Portland’s recycling rate in 1999 was 10 percent, meaning that only 10 percent of the waste generated by households was collected for recycling. Portlanders quickly became avid recyclers.

Just three years later, Portland’s recycling rate jumped to 32 percent and then to 38.7 percent prior to the new carts. While Portland’s dramatic increase in recycling is great news, too many recyclables continue to be thrown away because the bins were simply too small.

One study characterized and quantified collected residential trash over a three-month period. Among the key findings was that on average, 18 percent (by weight) of each trash bag at the curb was recyclable materials. This means that citywide, each year, Portlanders throw away 1,480 tons of recyclables valued at $133,000. Moreover, because the city does not pay ecomaine for its recyclables, but pays $70.50 per ton for trash, the city pays an avoidable $250,700 to dispose of recyclables as trash.

During this same study, based on weekly counts, the average number of curbside recycling bins per household was 1.7, and each week, 15 percent of all bins had significant overflow of materials that were typically placed on the ground next to the bin. This means that most residents used more than one bin; many bins were overflowing, resulting in higher labor costs for collection, and a significant amount of recyclables were disposed of as trash. These are all clear indications that the bins were too small.

A second USM study focused on the litter generated by the open-top bins. The research team collected, counted and categorized litter created specifically by the open-top recycling bins. Litter is created by wind, by the breeze from passing vehicles, by scavengers (human and animal) and by material stuck to the inside of bins that is subsequently dislodged.

About 6,280 pieces of litter, weighing 2,284 pounds, were created each week from the bins. Per year, this equates to 326,500 pieces of litter, weighing about 118,800 pounds. We calculated the labor required to collect each piece of litter as a proxy for direct economic impacts; it ranged from 17 cents to 79 cents per piece of litter, for an annual economic impact of between $55,515 and $257,980.

Litter also costs taxpayers because of additional efforts in cleaning impaired stormwater drains. The land-based litter (primarily plastics) that enters the ocean is recognized as an increasing national and global problem.

Portland’s new 65-gallon carts dramatically increase the capacity for recycling so only one container is needed, and there is now sufficient room for an average week’s worth of recycling. The carts have lids, which will significantly reduce the generation of litter, resulting in cost savings to city taxpayers. The lids also protect the contents from getting wet, especially paper and cardboard, which reduces their market value.

The new carts have two other important benefits. First, there is a reduced impact on workers, who previously had to repeatedly bend over to pick up bins, which is no longer necessary with the wheeled carts. Second, individuals who generate relatively small amounts of recycling no longer have to set out their recycling each week, as the larger carts can be set out only when full. This means fewer stops by city trucks, thus reducing operational costs.

With every solution there are new challenges, but these are far outweighed by the cost savings and environmental benefits. Most important will be the decreased litter, which in addition to a direct savings is one of the most common citizen complaints. Numerous studies have consistently shown that reducing litter results in a more positive experience for residents and visitors.