Anaerobic Digestion is the process of breaking down solid, organic material with little or no oxygen. Simply put, anaerobic digestion is the process of decomposition.
This process occurs both naturally and in man-made environments. In the wild, anaerobic digestion occurs in marshes and wetlands per Cal Recycle. In the built-environment, it occurs at facilities. The primary goals of anaerobic digestion facilities are:
- Divert organic waste from crowded landfills
- Reduce Green House Gas Emissions (GHG)
- Generate renewable energy in form of biogas, renewable natural gas or electricity.
Is Food Waste a Problem?
Yes! Per Our World in Data, food waste is responsible for 6% of global greenhouse gas emissions. That is a significant share of emissions for something that typically benefits no one.
Furthermore, the world produces enough food each year to feed every single person. Unfortunately, due to a number of factors including food waste, not everyone can get access to nourishment. Per the World Food Program, the world throws away $1 trillion dollars of food.
There is a large need to utilize all of the time and energy spent growing and cultivating the food that is normally sent to the landfill. Instead, that food waste should be diverted for some other societal use such as energy and compost.
What is the Benefit of Anaerobic Digestion Facilities?
The benefits of building these organically-fueled power plants is they divert waste from landfills and produce carbon neutral (or negative) power. Through the natural decomposition process, feasting bacteria break down organic material. A by-product of this is methane gas. Methane gas is a powerful greenhouse gas.
In fact, per the EPA, methane is 25 times more heat-trapping than carbon dioxide. By utilizing this naturally occurring greenhouse gas, communities can take advantage and produce renewable energy rather than just leaving the gas to rise into our atmosphere.
Anaerobic Digester in San Luis Obispo
Through a collaboration between Hitachi-Zosen (HZI) and local officials, the first anaerobic digestion facility for HZI in the US was built in San Luis Obispo (SLO) in 2017. You can watch a video of the construction here or below. Hitachi-Zosen is a multinational company with the motto: Waste is our Energy. Engineering is our Business. Sustainable Solutions are our Mission.
Through a combination of local organic waste sourcing, such as Cal Poly, residents of San Luis Obispo, and restaurants of San Luis Obispo, the plant generates enough power for 600 homes every year!
Rather than generating and transporting energy from hundreds of miles away, the anaerobic digester in SLO provides carbon-neutral electricity to thousands of residents right in their own backyard. This is one of many ways communities can tackle the challenges of Climate Change.
As a bonus, another byproduct of anaerobic digestion is good ol’ compost! Hitachi-Zosen sells this nutrient rich compost to local farms. Additionally, once or twice every year they provide compost to the community–free of charge!
Cal Poly’s Contribution to the Anaerobic Digester
In fact, Cal Poly, as a large contributor to the organic waste to the plant, has created a Zero Waste program led by Anastasia Lorraine Nicole. Ms. Nicole graciously spoke with us at SLO Climate Coalition to explain her role at Cal Poly. She explains, “the Cal Poly Zero Waste Program pays for itself”. So not only does the Zero Waste Program an environmentally-friendly program, but it is also a financially sound venture.
In 2017, Cal Poly’s Zero Waste Program achieved 90% landfill diversion. To achieve this, Cal Poly has provided a number of recycling and green-waste bins throughout the campus.
Ms. Nicole goes on to say, “Cal Poly contributes to the Hitachi-Zosen facility by collecting food waste from all cafeterias”. This adds up to a lot of food that would normally be discarded. Some of the non-spoiled and non-touched food can be donated to local food banks, however, most of the food would normally be sent to the landfill. With the anaerobic digester in town, that energy-dense food waste can be diverted to the facility for electricity generation.
What Can You Do to Support the Anaerobic Digester?
Recall the food waste bins the Integrated Waste Management Authority distributed a few years ago? Utilize those in your kitchen to place your food scraps. When the container becomes full, simply empty it in the green/organic waste trash bin. If you lost or misplaced your food scraps bin, you can easily use any sort of sealed container.
Additionally, be sure to collect and dispose of any yard trimmings into the green bin as usual. Altogether, the organic waste within your green bin eventually makes its way to the anaerobic digester across town.
One way you can think of it is the apple core you threw away in your green bin will be used to power your lights. Now that is cool!
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