|Mooove over coal. There’s something greener! Photo: Katie Kosirog, ESH&Q|
There is no doubt that humans create a lot of waste. It is impossible not to. But what if some of the nastiest waste we create from everyday life could create electricity? Some of the waste that Fermilab produces does just that. Wilson Hall’s kitchen has grease traps that get pumped out every two months by a waste hauler. The waste hauler, Darling Ingredients International, takes this smelly muck and mixes it with other organic waste in one of two places to create electricity: Fair Oaks Dairy Farm in Indiana or the Downers Grove Sanitary District. Each has anaerobic digesters that provide energy for their operations.
In anaerobic digestion, bacteria break down organic matter in the absence of oxygen. Biogas is the byproduct of this process, most of which is methane. The biogas is captured, cleaned and becomes fuel for an internal combustion engine, which can produce heat in the form of hot water and power in the form of electricity.
Fair Oaks Dairy Farm is the biggest dairy farm in the United States and operates completely off the grid. Manure from 33,000 cows along with other organic waste from places such as Fermilab is processed through anaerobic digesters. The Downers Grove Sanitary District uses sewage sludge in their anaerobic digester to power 50 percent of their operations in normal conditions, with a goal of 100 percent in the next few years. Places like these add restaurant and cafeteria food wastes to diversify the organic feedstock, which increases production of biogas.
Anaerobic digesters on farms and in sewage plants have multiple environmental benefits. Manure is managed in a safer way than traditional methods, reducing the risk of land and water contamination. Also, methane — a potent greenhouse gas with a global warming potential 21 times greater than that of carbon dioxide — is captured and converted to energy, decreasing air pollution directly released by the waste. Since the resulting electricity is not produced by conventional methods, the energy capture method has a multiplying effect in decreasing air pollution and greenhouse gases. And although the smell of cow manure isn’t pleasant, it can be contained within the digesters. With one cow producing 20 gallons of manure per day, a large farm can minimize their environmental impact tremendously by capturing the methane gas.
As population increases and traditional resources are depleted, anaerobic digesters, a renewable-energy technology, are viable waste management alternatives that maximize resources, and there are many ways to make use of them. The United Kingdom, for example, has a Bio-Bus that runs on sewage and food waste.
Minimizing waste and reducing greenhouse gas emissions are very important sustainability goals for Fermilab. Converting that waste into energy reduces greenhouse gas emissions in more ways than one. Fermilab’s contribution, about six tons per year, isn’t going to power anything on its own, but every little smelly bit helps.