Anaerobic Digestion Biogas
Anaerobic Digestion Biogas
Introduction
Organic matter, known as ‘feedstock,’ is processed through anaerobic digestion (AD) plants. Feedstock can come from a variety of sources such as food waste, farm waste and sewage. The plants can be standalone for industrial purposes (for example, food waste treatments plants), on-site (for example on-farm plants) or micro-digesters.
All AD systems produce biogas that can be used in several beneficial ways to generate heat and electricity.
The biogas produced by an AD plant composes of:
Methane and Carbon Dioxide pose the biggest threat at these concentrations.
Where Are These Gases Most Dangerous?
Post Digesters
Digesters
Storage Tanks
Health & Safety Risks Associated With a Biogas Plant
All the following risks are easily mitigated if health & safety are considered at all phases of a biogas project development. The risks include, for example:
- Fire and explosion
- Confined space hazards
- Risk of asphyxiation
- Risk of toxic gas poisoning (H2S, NH3)
- Risk of high-pressure gas or liquid leaks
H2S, CO2, and water make the biogas very corrosive causing potential leaks
Fire and Explosion
Under certain conditions, biogas in combination with air can form an explosive gas mixture. The risk of fire and explosion is particularly high close to digesters and gas reservoirs. It can occur because of a gas leak, creation of an explosive zone, welding, clogged or frozen pipes.
Risk of Asphyxiation
Biogas generation, transportation and flaring can lead to oxygen-deficient atmospheres. The biogas accumulation in a confined space can cause oxygen deficiency and result in poisoning or asphyxiation symptoms, even death.
The minimum regulatory oxygen content is 19%. The asphyxiants that are typical constituents of biogas are carbon dioxide (CO2) and methane (CH4).
How to Reduce Gas or Fire Risks
Speak to a gas detection expert to ensure you have the right gas detection equipment installed and all site workers wear the right gas detectors whilst operating in hazardous areas.
You’ll need to train every operator of the plant for the work in confined space, portable gas detection, process and equipment use
