This is an image of the new school lunch plate that some of the largest school districts in the country are using instead of polystyrene trays. It's made from recycled paper, and the plates — and any food scraps — can be turned into compost. (Urban School Food Alliance/Urban School Food Alliance)

This article has been updated.

Six of the largest U.S. school districts have pooled their collective purchasing power to make significant changes to school lunch, and they’re starting by jettisoning the polystyrene tray.

The Urban School Food Alliance, a coalition that includes the school systems of New York City, Los Angeles, Chicago, Miami-Dade, Dallas and Orlando, has commissioned a school lunch dish that is made from recycled newsprint and can be turned into compost after use.

The plate replaces trays made from polystyrene — most commonly known by the Dow Chemical brand name Styrofoam — a petroleum-based plastic that gets buried in landfills after use. Polystyrene, which can remain intact for hundreds of years, leaches pollutants into the water and air and is a major source of marine debris. (Dow notes that though many people erroneously refer to polystyrene drink and food containers as Styrofoam, the company’s material is not used to make food containers and instead is used as construction and insulation material and for floral and craft products.)

For those reasons, communities around the country are increasingly banning polystyrene containers — including the District, where the city’s restaurants and food trucks will have to give up foam plastic containers by January and the school system has transitioned away from the material. The Montgomery County Council voted in January to ban polystyrene containers by 2017, and the county’s school system has stopped using foam food-service trays.

Still, school districts across the country have clung to polystyrene trays because they are cheaper than compostable containers, costing an average of four cents each compared with 12 cents apiece for plates that can be composted.

But the six members of the Urban School Food Alliance leveraged economies of scale and commissioned a compostable tray at a cost of 4.9 cents each.

“We decided to grow our way out of a problem, to use our power as buyers to join with other large cities and use that purchasing power to move the market,” said Eric Goldstein, chief executive of the Office of School Support Services at the New York City Department of Education, which serves 860,000 meals a day, more than any other institution outside of the U.S. military. “It started out being three times more expensive, but now it’s a wash.”

Together, the six school systems spend $550 million a year on food and utensils, making it possible for them to benefit from economies of scale beyond what they could accomplish by placing individual orders.

The switch among the six districts to compostable plates will remove 225 million polystyrene trays a year from landfills, organizers say. The alliance, founded in 2012, represents districts that serve about 3 million students in 4,500 schools. Other school districts are closely following its progress and some have expressed interest in joining, Goldstein said.

“This is a big deal,” said Mark Izeman, senior attorney with the Natural Resources Defense Council, an advocacy group that has offered technical help to the alliance. “These school districts are moving forward without any federal, state or local mandates, and they’re doing it because it’s the right thing to do for the environment and the right thing to do economically. And it’s going to trigger other actions by cities and the private sector.”

The compostable round plate that the alliance will use is produced from recycled newsprint. It is approved by the Food and Drug Administration and made by Huhtamaki North America, which had to reconfigure its plant in Waterville, Maine, to accommodate the new product, Goldstein said.

The alliance’s round plate has five compartments, with a section for a drink in the middle to balance the weight of a typical meal. It is designed to be easy to handle, even by the youngest students.

D.C. Public Schools, which serves about 51,000 meals a day, has made the transition away from polystyrene. Lunch trays in the District are either a reusable plastic compartment tray that is cleaned by dishwasher or made from a compostable molded fiber or paper pulp, according to Rob Jaber, director of the Office of Food and Nutrition Services at DCPS. Trays, bowls, containers, cutlery and napkins are either recyclable or compostable, he said.

During the next two years, DCPS will phase in a recycling program for food waste and compostables at all of its 109 schools, said Beth Gingold of the D.C. Department of General Services. Schools will separate food scraps from compostable trays and other paper products and the waste will be sent to a composting facility in Prince George’s County, she said. Thirty DCPS schools began participating this year.

Compost is used as fertilizer in farming and gardening. Composing keeps food out of landfills, where it produces methane, a greenhouse gas.

The Urban School Food Alliance is considering other purchasing decisions to improve food quality and sustainability, Goldstein said. The coalition already has opted to buy chicken raised without antibiotics and is working on compostable cutlery, he said.

“We started with the plate because, symbolically, you build a meal from the plate up,” Goldstein said. “But we are looking to change the food and culture of our school cafeterias.”

Clarification: An earlier version of this article reported that the Montgomery County school system was phasing out the use of foam food-service trays; the school system has now fully phased out the use of such trays. The article has been updated.