Anaerobic digestion. Despite its futuristic-sounding name, it’s an alternative waste conversion process with its basic science having been around for centuries. The first recorded usage dates back to England in 1895. Now, as businesses continue to seek ways of reducing their carbon footprints and contributing to the goal of clean energy, anaerobic digestion is continuing to advance into the spotlight as a potential solution to waste management.
What Is Anaerobic Digestion?
Anaerobic digestion is a natural biological process where microorganisms, or bacteria, break down biodegradable organic matter like sewage sludge, food scraps, and manure. The digestion of the waste takes place in an airtight container without the presence of oxygen. The name anaerobic means “without air.” As the bacteria get to work, it produces a methane and carbon dioxide-rich gas called biogas. The physical byproduct of this bacteria buffet is a wet mixture called digestate that gets separated into solid and liquid. Although humans are responsible for creating this chemical reaction, it’s a process that happens naturally in the environment. Examples of natural occurrences of anaerobic digestion include swamps and in the stomach.
Both byproducts are something to get excited about. In its purest form, the biogas produced can be used for cooking, powering engines, and heating furnaces, as a chemical feedstock, or to generate electricity. When it’s treated and compressed, biogas can be upgraded to renewable natural gas, used as a renewable fuel source for vehicles. As for digestate, it can be used as an industrial co-product, as a nutrient-rich fertilizer, compost, animal bedding, and soil amendment.
Many believe it’s one of the many ways that we can reduce our carbon footprints, combat climate change, and find replacement energy sources to the dwindling resources we currently have.
How Does Anaerobic Digestion Work?
The process begins when waste, also referred to as feedstock, is loaded into an airtight container called an anaerobic digester. Once inside, the feedstock undergoes four different stages of being broken down through chemical reaction before reaching its final form as raw material that’s able to be used in many ways.
The first stage is called Hydrolysis. Here, complex matter like carbohydrates and proteins gets broken down into sugars and amino acids. Next up is the acidogenesis stage. Bacteria break down sugars and amino acids even further, reducing them into ethanol and fatty acids, as well as creating the byproducts like ammonia, carbon dioxide, and hydrogen sulfide. When the feedstock reaches acetogenesis, the third stage, the ethanol, and fatty acids are converted into hydrogen, carbon dioxide, and acetic acid. And in the final stage of anaerobic digestion, called methanogenesis, the bacteria convert the leftover hydrogen and acetic acid into the methane and carbon dioxide-rich biogas.
The timeline for digestion depends on factors such as how much waste is loaded into the digester, if more than one kind of matter is present (this process is called co-digestion), and the temperature inside of the digester. With all these factors considered, complete digestion can take between 14 to 40 days. And after its total breakdown, the biogas is collected, treated, and sent off to be used as renewable energy.
What Are the Benefits of Using Anaerobic Digestion?
Using anaerobic digestion as an alternative waste management approach features a whole host of benefits to the environment as well as human health. It’s a much-needed solution in countries like the U.S. where, according to the Environmental Protection Agency (EPA), more than 40.7 million tons of organic waste were produced in 2017. Another staggering fact is that only 2.6 million tons of the food waste generated that year was said to have been composted, or 6.3%.
One of the many benefits of employing anaerobic digestion is the reduction of the amount of waste we send to landfills. The EPA further states that 86-90% of food waste is highly biodegradable and can even help break down tougher materials like livestock waste. And by collecting the biogas and converting it for better use instead of releasing it into the atmosphere, we cut down on harmful greenhouse emissions. Other benefits include reducing our dependency on fossil fuels and replacing it with biomethane gas and protecting water sources from runoff and contaminants that may harm water supplies, animals, and plant life.
Despite anaerobic digestion being such an effective and highly regarded waste management alternative, it’s still a significantly underused resource. Currently, there are more than 2,000 sites in the U.S. that use anaerobic digestion, mainly found in agricultural, wastewater, and urban settings. It’s believed that there is room for up to 13,500 more sites for anaerobic digesters to be built in the U.S.
Where Synergy BurCell Technologies Comes In
The world’s population continues to rise, and so does the number of countries that are searching for better recycling and waste management options. Synergy BurCell Technologies is here to provide a solution. We are dedicated to the goal of clean energy and a better world and we have found a cost-efficient, environmentally friendly way of ensuring less trash goes to waste. Our state of the art BurCell System uses a vacuum aided thermal decomposition process that breaks down food, paper, and other organic wastes, creating a highly digestible feedstock that has demonstrated an increase of some 30% more biogas from those organic feedstocks when used for anaerobic digestion.
Utilizing our proprietary BurCell System, a Synergy BurCell designed material recovery facility provides clean, energy-rich feedstocks that can become a source of reliable renewable energy from anaerobic digestion while recovering valuable non-organic materials that can be reused. Our projects will recover and reuse as much as 75% of the materials we process, a much-needed improvement on current waste management methods.
For more information about the BurCell system and how it works, contact our team today!