PORTLAND — Portland Public Schools will no longer use Styrofoam trays in their cafeterias beginning this school year.

The Portland district will replace them with paperboard trays. The additional $30,000 annual cost will be offset by savings anticipated from district recycling and composting programs.

Reusable plastic trays will be used once a new central kitchen is finished and operates a tray-washing facility.

During the past year, nearly all of Portland’s mainland schools have implemented composting, trash separation and recycling of bottles and other refuse from the cafeteria. Those changes have reduced cafeteria trash by 50 to 80 percent.