Stop & Shop is working toward becoming a zero-waste supermarket chain and much of that waste reduction happens at its mammoth central distribution warehouse north of Fall River.

A modest portion of the 1-million-square-foot facility is dedicated to recycling, repurposing and converting inedible food to energy and compost. Trucks returning from deliveries to the 210 stores in Connecticut, Massachusetts and Rhode Island bring back recyclables such as cardboard and plastic bags. The trucks also carry other materials diverted from the waste stream. Pallets and crates are collected and shipped back to food companies. Wax-coated cardboard boxes are sent to India, where the wax is removed and made into candles. Buckets and pill bottles from in-store pharmacies are emptied and recycled.

“We’re putting everything back in our trucks, which are coming here anyway. So we are not adding to our carbon footprint,” said Roger Beliveau, manager of distribution services at Stop & Shop.

Meat is frozen on its expiration date and donated to food pantries through a program called Meat the Needs.

Most of the remaining edible food is collected by food banks, such as the Rhode Island Food Bank and the Greater Boston Food Bank. Stop & Shop is the largest food donor to both organizations.

About 100 tons of inedible food and organic material, such as expired yogurt, eggs and flowers, make its way to the Green Energy Facility daily. The 24/7 anaerobic digester and power plant is fed with these past-due items, much of them still in their packaging.

Nothing is wasted. A large screw press shreds and spins the material removing plastic, any other inorganic packaging, rinds and seeds. This stringy residue is collected and shipped to a commercial compost facility, where it’s mixed with organic material and eventually transformed into a soil amendment.

No outside water is added to the operation. The liquid taken from the screw press is recirculated for heating and eventually ends up in a 100,000-gallon holding tank. The tank delivers a slow but steadying slurry to a 1.2-million-gallon anaerobic digester. The giant enclosed pool of bacteria releases gases that are burned in a 1.1-megawatt generator. The power is fed into the electric grid and equals 40 percent of the energy used at the distribution center.

Managed by the Concord, Mass., company Divert, the operation must run nonstop to stay in balance and maintain its energy output. A science laboratory continuously monitors and tests the gas and slurry to ensure that the fuel mixture is ideal. An organic compost is the final byproduct. The compost is collected and used by a landscaping company in Tiverton, R.I.

The Green Energy Facility opened in April 2016. Stop & Shop won’t say how much the separating equipment, anaerobic digester and generator cost but company officials expect to break even on their investment soon.

Beliveau said the benefit is immeasurable. “The payoff is you don’t put a price on the environment,” he said.

The original article can be found at ecoRInews.