Putting Food Waste to Work


Kroger Supermarkets is now the first company to utilize the process of anaerobic digestion as a way of powering its facilities.  But what exactly does this mean and how are they achieving that goal?  The answer is simple: BIOGAS.

We all know that food gives us energy, but how could our food generate enough energy to power an entire supermarket? Many different forms of organic waste can be used to run anaerobic digestion; however, food waste holds the most stored energy of all these ‘ingredients.’ Carbohydrates, proteins and lipids are all readily converted to biogas as is the wastewater that contains food waste by means of anaerobic digestion.  Therefore, food waste alone has the potential to sustain entire businesses.

When anaerobic digestion occurs, a mixture of methane, carbon dioxide and other trace gases combine to form biogas. Because biogas is renewable it offsets non-renewable resources, such as coal, oil, and fossil fuel-derived natural gas. Producing biogas creates U.S. jobs and benefits local economies. Biogas can be used to replace natural gas in many applications including: cooking, heating, steam production, electrical generation, vehicular fuel, and as a pipeline gas.

In nature, biogas comes from locations such as landfills, covered lagoons, livestock operations, etc. anywhere there exists organic decomposition. In controlled environments, like at Kroger’s Compton Facility, the food waste is fed into the anaerobic digester, where it will be shredded, mixed, processed, exposed to heat, and stripped of pathogens while promoting the growth of microbes all to aid in the breakdown of the waste producing biogas.

Eventually, the usable biogas is stored in gas holders until it is needed for its energy. This biogas contains so much thermal energy that it can very easily be converted into a source of electricity.

Instead of land-filling spoiled apples, Kroger decided to capitalize on their energy potential by means of anaerobic digestion. As a result, Kroger is not only being eco-friendly by reducing methane emissions, but it is also being smart economically, as the company is now saving enormous amounts of money on energy.

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