Sustainable energy is at the apex of everyone’s priority, and it does not get any better than renewable energy. The more facilities there are which produce such energy, the less bleak the future looks. A wider access to renewable energy means that the next generation has the best chance at also experiencing the convenience and advancements that comes with having access to power and energy. There are different scales at which this type of energy can be produced at, and we will focus mostly on the commercial level and not too much on the individual side of it.
Renewable energy can be produced in many ways, and one of those ways include anaerobic digestion. Anaerobic digestion, or methanization, uses the process of fermentation to break down organic matter from animals, plants, or sewage to produce biogas. The process takes place within a centralized system in a unit called an anaerobic digester, also known as a biogas reactor or a bio-digester. The substrate which results from the digestion is kept in an oxygen free vessel and heated to approximately 37°C to 38°C (sometimes more than 50°C) and stirred continuously. After at least 20 days and a series of bacteria-induced chemical transformations, the fermented biomass produces biogas. The biogas contains 40% to 70% methane (CH4), the same as natural gas from a hydrocarbon deposit. The remaining gas is carbon dioxide (carbon dioxide (co₂)), plus small amounts of sulphur.
The produced biogas may be used on-site in a cogeneration engine for producing heat and power or it can be purified with membranes to extract the methane for injection into the public natural gas network or for use as transportation fuel. This is how diesel is produced organically. This is of course on a commercial level.
Many strides have been made by several companies to encourage people to use a cubic meter digester for their food waste. These digesters become part of a built-in kitchen set that speeds the process of digesting food waste. People like farmers obviously may go for more volume than the normal one cubic meter, because they have so much to digest, and they can use the resulting substrate for a lot of things. They sometimes mix it with the manure from their livestock operations to profitably produce energy while reducing their disposal costs and pollution. Some farmers go as far as growing crops which are harvested for the purpose of creating sustainable energy. It’s part of their business model.
Alternatively, most people employ the use of a tumbler compost, which also digests food and create nutritious soil that can be used as fertiliser by those same farmers. Whilst this way of “anaerobic digestion” is not totally oxygen free and does not necessarily lead to the creation of power and energy, it does play a role in making the world more sustainable – what is more important than that? Optimistically speaking, the future does look bright, we simply need to start practicing these sustainable ways of producing energy moving forward.