How Anaerobic Digestion turns food waste into energy?

Converting food waste into energy is an excellent method of generating usable energy in an environmentally friendly way. The process that is used to do this is called Anaerobic Digestion, this process takes place in specialist AD Plants where the waste is broken down and biogas is given off.

What is Anaerobic Digestion?

Anaerobic Digestion is a process in which bacteria is used to break down organic matter. Wastewater biosolids, animal manure, and food waste is commonly used within the process which takes place in the absence of oxygen.

The reaction takes place in sealed vessels called reactors. The reactors are specifically designed for each particular site and feedstock and contain complex microbial communities which break down the food waste.

How does Anaerobic Digestion work?

The Anaerobic Digestion (AD) process takes place in a number of stages, the first of which is the collection and transportation of the feedstock, including food waste, to the AD Plant. Once at the plant, any contaminants and non-digestible materials are removed, and the feedstock is pre-treated so that it is ready for processing.

After pre-treatment has been completed, the food waste and other organic matter is placed into the reactor. It is in the reactor that the reaction takes place, and the feedstock is broken down by naturally occurring microorganisms. The conditions within the reactor, including temperature and gas composition, are carefully monitored, and maintained in order to optimise the digestion process.

As the feedstock is decomposed two products are left over – biogas, in the form of methane, and a sludge-like material known as digestate. These products are then captured and collected and used for a variety of purposes, including the generation of energy.

Infographic showing the AD Process.

What is biogas used for?

Biogas has many uses; however, its primary use is in CHP (Combined Heat and Power). CHP is an extremely efficient method of generating heat and electricity that can be used in place of traditional power stations and boilers. The use of biogas in CHP can decrease carbon emissions by up to 30%.

Biogas can also be used as a fuel for cars and other motor vehicles. The most common example, currently, is its use in many city buses. Using biogas in place of conventional fuels, such as petrol and diesel, can have significant environmental effects due to biogas’ lower carbon emissions when burned.

The benefits of Anaerobic Digestion

The AD process tackles two environmental issues simultaneously, the first being that it reduces the amount of waste the is sent to landfill. Food waste often ends up in landfills where the gases given off during decomposition contribute to climate change through the greenhouse effect.

Anaerobic Digestion also provides an excellent renewable alternative energy source to fossil fuels. As the process requires no combustion, so the effects of greenhouse gases in the atmosphere are all but eliminated.

Is turning food waste into energy an effective solution?

The world is becoming inundated with more and more food waste, which is turning into a serious environmental issue. Having a productive solution to use this waste in a useful way can significantly reduce the amount of waste that is sent to landfill.

Anaerobic digestion in AD plants is an extremely effective solution for using this food waste to create useful fuels, fertilizers, and electricity to power homes. Harnessing this renewable resource at a global level can have a huge impact on carbon emissions and the amount of greenhouse gases that are released into the atmosphere.

Our AD Plant Gas Analysers