The short answer is (wait for it…) nothing.
Anaerobic digestion is a natural process that has been around since the beginning of life on earth. As a technology, the process has been used for more than a hundred years as a means of breaking down waste matter so that water and sewage may safely be returned to the environment without risk of bacterial contamination of fresh water.
Most of the wastewater treatment plants in operation today use some form of anaerobic digester.
The new push is to utilize this technology to address organic waste going to landfill. When food scraps, table waste, and industrial food production waste goes to landfill, it undergoes the same process, the only difference being that the methane produced in the landfill is often not captured. Methane is a radically potent greenhouse gas, somewhere between 20-35 times as powerful as carbon dioxide.
Methane in landfills can seep into the ground, where it can contaminate drinking water and soils. There are methods to capture the methane coming from landfills, particularly those which have been in operation for some time.
What anaerobic digestion offers is a process by which most of the methane/ energy potential of waste going to landfill is captured before it is buried. Not only does it become largely unnecessary to try to recapture methane in the landfill, but the need to expand landfill space, and its associated costs can be postponed. It is not a complete solution to landfill expansion, but just as recycling of plastics, paper, and aluminum help reduce waste in the landfill, so does anaerobic digestion.
Not only does industrial anaerobic digestion keep these problematic wastes out of the landfill, but the energy that goes into producing food is ‘recycled’, reducing the need to pump fossil based gas out of the ground, extending the life of these vital fuel sources as well.
The bottom line is that anaerobic digestion only makes sense. Reduce the waste going to landfill, reuse the energy contained in those organic wastes, and recycle those products into fertilizers, soil amendments, and fuel sources.
The ‘green’ mantra Reduce, Re-use, Recycle—taken to the next step.