Palas: When a company produces 150 tons of food waste every day, that is either a huge problem or a great opportunity to innovate and produce energy. New waste-to-energy technologies can transform this food waste into clean, green energy while also providing a bonus in reducing the amount of waste that goes into landfills.

An estimated 35 million tons of food waste from commercial and residential sources end up in US landfills each year, according to the US Environmental Protection Agency. Operators of waste generators are increasingly looking for more environmentally sound ways to manage food waste than sending it to a landfill and with good reason: Waste is expensive.

FE: What is the economic cost of food waste?

Palas: For food manufacturers, on average, 16 percent of raw materials are lost during manufacturing.  Dana Gunders , author of the Natural Resources Defense Council report “Wasted: How America is Losing Up to 40 Percent of Its Food from Farm to Fork to Landfill,” noted that 40 percent of food in the United States today goes uneaten. She noted that uneaten food rotting in landfills is the single largest component of US municipal solid waste, where it accounts for a large portion of US methane emissions. At the processing level, the losses come mostly through trimming, when both edible portions (skin, fat, peels and end pieces) are removed from food. 

Food products make up 63 percent of a supermarket’s disposed waste stream, according to a California Integrated Waste Management Board industry study. That’s approximately 3,000 lbs. thrown away per employee every year. The stores can’t sell the food, so they toss it into the compost or garbage.  Supermarkets lose about $15 billion annually in unsold fruits and vegetables alone.

Large food companies can tell you that trucking food waste to distant landfills is costly, and decomposing organic waste in landfills can cause a host of environmental problems. Some US states already have legislation in place that encourages the reduction of food waste sent to landfills and will effectively ban food waste from landfills over the next 10 years. Today’s technologies and available solutions were developed and proven to enable the collection of different kinds of food leftovers.

FE: What exactly is waste to energy?

Palas: The waste-to-energy process starts when food is brought to the center and put through a blending system that removes any inorganic material—namely packaging, such as plastic, metal and glass—and liquefies the food. The organic material that is mixed with wastewater from the creamery??? is all the remains. That mixture goes into an anaerobic digester, an oxygen-free piece of equipment full of microbes, that breaks down the food, producing biogas and a mix of nutrients and minerals. The biogas is then compressed and purified on its way to the campus’ micro turbines and boilers, where it takes the place of nearly all of the natural gas the center previously used.

FE: Can you name a company that has made serious changes about its waste?

Palas: One company I’m constantly using as a good example would be Kroger Co., one of the largest supermarkets in the US, with 2,400 supermarkets in 31 states. Last year, the company unveiled a clean energy production system that now converts food that could not be sold or donated into clean energy to help power its Ralphs/Food 4 Less distribution center in Compton, California. The biogas provides 20 percent of the campus’ power and has delivered an 18 percent return on investment for the project so far.

FE: How was the company able to accomplish changes with waste-to-energy technology?

Palas: The newly installed anaerobic conversion system created for Kroger is carried out in an enclosed, oxygen-free environment, which means the process takes up less space and generates no odors. The system will provide enough renewable biogas to offset more than 20 percent of the energy demand of the Ralphs/Food 4 Less distribution center. The new system processes more than 55,000 tons of organic food waste into renewable energy annually and provides power for the over 650,000-square-foot distribution center. By diverting that food waste—the equivalent of 150 tons per day—the system will also reduce area truck trips by more than 500,000 miles each year, according to the company. 

Combining the use of renewable energy power with more than 150 zero-emission fuel cell forklifts, the Ralphs/Food4Less distribution center is now one of the greenest and most efficient, advancing Compton as a leading sustainable community.

Kroger says its investment in the biogas digester will be paid back within five years, an 18.5 percent return on investment. It’s not surprising that Kroger is now considering adding biogas to other distribution sites.

FE: What are the returns on waste to energy for food manufacturers?

Palas: Reuse is the key factor here:

• Reuse of returns and dead stocks. With nearly 16 percent of raw materials lost during manufacturing, WTE may help draw back returns on this loss.
• Reuse of both solid and liquid organic waste coming out of their production facilities.
• Reuse of the residual heat created by the CHP systems during the energy production process for internal needs, such as steam, heat, cooling and hot water, dramatically reducing their energy cost.

There are other incentives as well:

• Big brands that process animals as part of their production process can implement the same program on the farms growing the animals to eliminate the contamination created by animal manure.
• The projects can be implemented by the food companies or by companies such as Bluesphere, which is ready to establish and operate these facilities on a build, own and operate basis.

FE: What would be the draw for food manufacturers and engineers?

Palas: New anaerobic digestion technologies make waste to energy an attractive financial and operational option for large food manufacturing companies.  The savings that can be created, as well as the reduction in waste streams and resulting environmental benefits, can set a new standard for best practices in the industry.

The environmental benefits of efficient resource use and the financial benefits of significant cost savings result in an ultimate win-win approach. The adoption of “green” practices also appeals to consumers who are increasingly aware of a company’s environmental policies. Implementing waste to energy therefore may deliver not only the economic benefit of savings for food engineers and manufacturers, it may also increase food manufacturers’ sales as a result of consumer perception. Ultimately, as some of the largest generators of food waste resulting from scraps and byproducts, food manufacturers have a great opportunity to become the leaders in waste to energy.