The anaerobic digester might just be the coolest machine you’ve never heard of. The digester is currently being utilized to turn 40% of unusable food from supermarkets into energy. The system is also helping to cut waste by 150 tons a day, thereby reducing grocery stores’ overall environmental footprint.
In a sprawling Compton distribution center that Ralphs shares with its fellow Kroger Co. subsidiary Food 4 Less, organic matter otherwise destined for a landfill is rerouted instead into the facility’s energy grid.
So how does it work?
Once the moldy bread, rotten meat, and discarded fruit and veggies from 359 stores make their way to the center, the anaerobic digester goes to work. The food that is unable to be donated or sold is then dumped into a massive grinder — cardboard and plastic packaging included.
After being ground up, the mass is sent to a pulping machine, which filters out inorganic materials such as glass and metal and mixes in hot wastewater from a nearby dairy creamery to create a sludgy substance. From there, the sludge is transported into a storage tank, and then eventually a 2 million gallon silo. Continue reading
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