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What is Anaerobic Digestion and why should it be encouraged?

Anaerobic digestion is the conversion of biodegradable material in sealed vessels in the absence of oxygen by a consortia of bacteria and Archaea from which a valuable biogas and a digestate are produced. This biogas is collected and typically utilised as a source of energy. Digestate from the process can be utilised as a fertiliser (replacing mineral fertiliser) and as a soil conditioner. Alternative uses for biogas and digestates are currently being evaluated.

AD has already been implemented across many countries in Europe to treat biodegradable organic wastes such as source segregated food waste, organic fraction of municipal solid waste (OFMSW), biodegradable commercial and industrial (C&I) wastes, sewage sludges, agricultural residues and animal slurries as well as to generate energy from energy crops. The UK has already seen a significant deployment of anaerobic digestion technology for treating sewage sludge and some progress is being made recently in the establishment of this technology for treating other organic materials.

Anaerobic digestion is an attractive option for Wales and the UK as it can contribute towards meeting targets for waste recycling and diversion of organic wastes from landfill, the requirement to pre-treat organic materials prior to disposal, targets to reduce greenhouse gas emissions and the requirement to generate renewable energy.



AD Events and Projects

Representatives of the AD Centre often present our latest research outputs and state of the art developments in the AD sector at events across the UK, internationally, and online. These events, or a selection of others that may be of interest will be posted here. Information to a selection of external research projects that are of interest to the AD Sector will also be posted here.


ALG-AD 'Creating value from waste nutrients by integrating algal and anaerobic digestion technology'


Scientists at Swansea University have been leading the Interreg NWE funded ALG-AD project, where the main objective is to use the nutrients in digestate to cultivate microalgae, and generate products of value.

Microalgae are versatile microscopic organisms that have the ability to consume the nutrients remaining after the anaerobic digestion of food and farm waste.  The biomass produced is rich in protein and depending on the microalgal species selected can contain useful oils.   Scientists are now testing the hydrolysed algal biomass, rich in peptides, as an animal feed ingredient for piglets and fish. There is also great potential for much wider application of this microalgal biomass for use in a diversity of market sectors. Examples include carotenoids with antioxidant properties for use in the health and cosmetics sector, and biostimulants for use in the agricultural sector.

The ALG-AD team can help AD and other organic waste businesses to explore opportunities to valorise waste streams using microalgae, and we welcome any interested members of the Wales AD network or beyond to contact our colleagues at Swansea University. Please follow the ALG-AD social media channels and take a look at the website to find out more. You are also welcome to contact members of the team. 

Louise Hall - Project Manager -

Professor Carole Llewellyn, PI –

Dr Alla Silkina –

Dr Claudio Fuentes Grunewald - 

AD-ALG pilot reactors

AD-ALG Pilot Reactors

AD-ALG Interreg logo