Anaerobic Digestion

The following services are offered to industry;

  • Biochemical Methane Potential (BMP) assays
  • Feedstock analysis and pre-treatment
  • Reactor and pilot scale trials
  • Process development, design and modelling
  • Process monitoring and optimisation
  • Operational analysis
  • Expert advice and training

The Anaerobic Digestion (AD) process is a natural biological process where microorganisms breakdown biodegradable organic matter in the absence of oxygen. The process produces biogas that contains 60-70% methane gas, 30-40% carbon dioxide with traces of hydrogen sulphide and ammonia. The biogas produced can be utilised as a source of energy when the methane component is burnt in a Combined Heat & Power (CHP) plant, directly injected into the gas grid or compressed for liquid transport fuel.

Organic polymers such as carbohydrates, proteins and fats are degraded by the AD process in four phases: hydrolysis, acidogenesis, acetogenesis and methanogenesis. The process is enclosed to ensure anaerobic conditions, increase biogas capture and reduce any potential odours that are common with current waste management technologies such as landfilling or In Vessel Composting (IVC).‌

Anaerobic Digestion

The following services are offered to industry;

  • Biochemical Methane Potential (BMP) assays
  • Feedstock analysis and pre-treatment
  • Reactor and pilot scale trials
  • Process development, design and modelling
  • Process monitoring and optimisation
  • Operational analysis
  • Expert advice and training

The Anaerobic Digestion (AD) process is a natural biological process where microorganisms breakdown biodegradable organic matter in the absence of oxygen. The process produces biogas that contains 60-70% methane gas, 30-40% carbon dioxide with traces of hydrogen sulphide and ammonia. The biogas produced can be utilised as a source of energy when the methane component is burnt in a Combined Heat & Power (CHP) plant, directly injected into the gas grid or compressed for liquid transport fuel.

Organic polymers such as carbohydrates, proteins and fats are degraded by the AD process in four phases: hydrolysis, acidogenesis, acetogenesis and methanogenesis. The process is enclosed to ensure anaerobic conditions, increase biogas capture and reduce any potential odours that are common with current waste management technologies such as landfilling or In Vessel Composting (IVC).‌

Publications

Book Chapters

Akunna J.C. Anaerobic treatment of brewery wastes. In, Brewing Microbiology: Managing Microbes, Ensuring Quality and Valorising Waste. Edited by A.E. Hill. Woodhead Publishing, Elsevier. [In press]

Akunna J.C. and Bartie J. (2014). Wastewater treatment, infrastructure and design. In, Water Resources in the Built Environment – Management Issues and Solutions. Edited by C. Booth and S. Charlesworth. John Wiley & Sons Ltd, Chichester, United Kingdom, ISBN 978-0-470-67091-0, 350-370.


Selected Journal Papers

Obata, O., Akunna, J. C. and Walker, G (2015). Hydrolytic effects of acid and enzymatic pre-treatment on the anaerobic biodegradability of Ascophyllum nodosum and Laminaria digitata species of brown seaweed. Biomass and Bioenergy, 80, 140-146 (doi: 10.1016/j.biombioe.2015.05.001). http://authors.elsevier.com/a/1R3~D3QkGxbtQM 

Hierholtzer, A. and Akunna, J.C. (2014). Modelling start-up performance of anaerobic digestion of saline-rich macro-algae. Water Science & Technology, 69(10), 2059-2064 (doi: 10.2166/wst.2014.100).

Hierholtzer, A., Chatellard, L., Kierans, M., Akunna, J.C. and Collier, P.J. (2013).The impact and mode of action of phenolic compounds extracted from brown seaweed on mixed anaerobic microbial cultures. Journal of Applied Microbiology, 114 (4), 964-973 (doi:10.1111/jam.12114).

Hierholtzer, A. and Akunna, J.C. (2012). Modelling sodium inhibition on the anaerobic digestion process. Water Science & Technology, 66(7), 1656-1573. (doi: 10.2166/wst.2012.345).

Kwiatkowska, B., Bennett, J., Akunna, J.C., Walker G.M. and Bremner, D.H. (2011). Stimulation of Bioprocesses by Ultrasound. Review article. Biotechnology Advances, 29(6),  768-780, November. (doi: 10.1016/j.biotechadv.2011.06.005).

Al-Alm Rashed, I. G., Akunna J., El-Halwany M. M.,   Abou Atiaa, A. F. F (2010). Improvement in the efficiency of hydrolysis of anaerobic digestion in sewage sludge by the use of enzymes. Desalination and Water Treatment, 21, 280-285. (doi: 10.5004/dwt.2010.1575).

Mallick P., Akunna J.C. and Walker G. (2010). Anaerobic digestion of distillery spent wash: influence of enzymatic pre-treatment of intact yeast cells. Bioresource Technology, 101, 1681-1685.

Shanmugam, A. and Akunna J.C. (2010). Modelling head losses in granular bed anaerobic baffled reactors at high flows during start-up. Water Research, 44, 5474-5480. (doi:10.1016/j.watres.2010.06.062).

Akunna J.C., Kazi H. and Kerr K. (2009). Estimating methane production potential of an old municipal landfill. The Journal of Solid Waste Technology and Management, 35(3), 156-161.

Abdullahi, Y.A., Akunna, J.C., White, N.A., Hallett, P.D. and Wheatley R. (2008). Investigating the effects of anaerobic and aerobic post-treatment on quality and stability of organic fraction of municipal solid waste as soil amendment. Bioresource Technology, 99, 8631-8636. Akunna, J.C., Abdullahi, Y.A. and Stewart, N.A. (2007). Anaerobic digestion of municipal solid wastes containing variable proportions of waste types. Water Science & Technology, 56(8), 143-149.

Baloch, M.I., Akunna, J.C., M. Kierans and Collier, P.J. (2008). Structural analysis of anaerobic granules in a phase separated reactor by electron microscopy. Bioresource Technology, 99, 922-929.

Shanmugam, A. and Akunna J.C. (2008). Comparison of the performance of GRABBR and UASB for the treatment of low strength wastewaters. Water Science & Technology, 58(1), 225-232.

Baloch, M.I., Akunna, J.C., and Collier, P.J. (2006). Carbon and nitrogen removal in a granular bed baffled reactor. Environmental Technology, 27(2), 201-208.

Baloch, M.I., Akunna, J.C.; Collier, P.J.  (2006). Assessment of Morphology for Anaerobic-Granular Particles. Water Environment Research, 78(6), 643-646.

Baloch, M. I. and Akunna, J.C. (2003). Granular bed baffled reactor (GRABBR): A solution to a two-phase anaerobic digestion system. American Society of Civil Engineers (ASCE) Journal of Environmental Engineering, 29(11), 1015-1021.

Research & Consultancy

Research Themes

Current AD research undertaken at Abertay University:

  • Pre-treatment - enhancement of the anaerobic digestion process by preliminary processing of feedstock to promote readily utilisable substances and thereby increasing the biogas production.
  • Process modeling - prediction of various biochemical pathways in the anaerobic digestion process.
  • Adaptation - gradual acclimation of the microbial system in order to tolerate the distinctive conditions, ensuring stability and to reduce sensibility in the process.
  • Co-digestion - at least two different types of feedstock run simultaneously in a single treatment facility to overcome the deficiency that one substrate could impose in the AD process.
  • New Biomass - Macro Algae; Pyrolysis Oil.

Selected Research & Consultancy Projects

Scottish Biofuel Project (ERDF, Scottish Government, Scottish Enterprise)
The Scottish Biofuel Programme (SBP) provides a wide range of expertise, engaging directly with small to medium sized enterprises (SMEs) in the Scottish business sector, facilitating the conversion of biomass waste to energy; test and implement conversion of biomass waste to energy and the production of sustainable biofuels.
 
Seaweed Anaerobic Digestion (UK Government) - This study was undertaken to evaluate the biological methane potential of seaweed found around the coasts of Scotland.  The main objective of the research product was to subject the seaweed feedstock to a range of batch and reactor studies to obtain knowledge of the methane potential. It was identified that the presence of inhibitory compounds such as sodium chloride or polyphenolics could affect the biodegradation process of the seaweed leading to a reduction in the methane yield.
 
Tennant's Wellpark Brewery - This study involved pilot testing a Granular Bed Baffled Reactor (GRABBR) anaerobic wastewater treatment technology to improve the quality of waste water from the brewing process in Glasgow.
 
Riverside Landfill (Dundee City Council) This study involved the development of novel and effective strategies for assessing and predicting methane generation from a closed municipal landfill. It also involved development of assessing risks posed by landfill sites for various site re-use options.  This study informed stakeholders of the cost/nature of interventions necessary to rehabilitate the landfill site, pursuant to which, the site was transformed into a 35 hectare nature park (Dundee Riverside Nature Park) with views over the River Tay.
 
Tio Ltd (Interface) - Tio Ltd who specialise in packing organic root vegetables required a methane yield evaluation of their process waste and farm waste feedstocks to assist them to evaluate the feasibility of building their own AD plant.  It was envisaged that a Combined Heat & Power (CHP) plant would burn the biogas with electricity exported to the National Grid and the excess heat generated would be supplied to local companies surrounding the AD development. The resulting digestate would be spread on company owned fields to provide a sustainable source of nutrients for crops. Interface Case Study  http://www.interface-online.org.uk/case-studies/tio-ltd

Eco ideaM Ltd (Scottish Biofuel Project) - Eco ideaM Ltd with assistance from the Scottish Biofuel Project (SBP) designed a project to investigate the energy potential of pyrolysis co-products that would add value to a standard biomethane production system. The compounds derived from a pyrolysis process are very complex due to their high molecular weight and inability to dissolve in water.  With this in mind a BMP test was undertaken to see if AD would be a suitable methodology to increase the calorific value of pyrolysis co-products before combustion in a Combined Heat and Power (CHP) plant. 

Macsween Ltd (Scottish Biofuel Project) - Macsween Ltd required a compositional analysis of the effluent water and food process waste generated on their manufacturing site in Loanhead. Once this stage was completed the gas yield of the feedstocks was evaluated with the objective of providing Macsween with an insight into the suitability of AD to manage and add value to their waste outputs.


Recent examples of Knowledge Transfer Partnerships (KTPs) related to Anaerobic Digestion at Abertay University:

Diageo PLC - Building on the expertise held within Abertay University of organic waste management and renewable energy production, Diageo PLC were investigating the options available within their Scottish operation to utilise clean technologies such as AD to manage the residual organic materials created by their distilling operations.

Ivan Wood Ltd - The Food Innovation @ Abertay team and UWTC have come together to assist Ivan Wood Ltd in the design, fabrication and validation of an innovative filtration system that will treat the liquid and solid wastes generated by fresh vegetable preparation and utilise the recovered waste products in new products.

Education & Training

Postgraduate Taught Courses

Abertay University offers a full time MSc course that focuses on the key sustainability issues such as depletion of natural resources, maximising energy usage and reducing environmental impacts that are found on a day to day basis within business and industry.  The course provides participating students with informative lectures and seminars that provide the baseline knowledge that is then applied to real life situations using group work and a full dissertation on a selected environmental topic.


Research Degree Opportunities

The Urban Water Technology Centre has research degree opportunities that are focused on specific feedstocks and the parameters that may influence the efficiency of the AD process.  Some examples of the research topics that have been defended at PhD level are described below:

  • Investigating factors affecting the anaerobic digestion of seaweed: modelling and experimental approaches.
  • Analysis of key requirements for effective implementation of biogas technology for municipal solid waste management in Sub Saharan Africa. A case study of Kigali City, Rwanda.
  • Optimisation of anaerobic digestion of organic solid waste for the production of quality compost for soil amendment.
  • Carbon and nitrogen removal in a granular bed baffled reactor.

Continuing Professional Development

International Intensive AD Training - Practical Digester Biology

Date: 6-8 July 2015   Venue: Abertay University.   IBBK, REA and Abertay University will provide a 3 day intensive AD training course in Dundee, UK. Refresh your knowledge, be brought up to date on the latest state of the art technology by our experienced team of experts. Be part of lively discussion and benefit from the knowledge of the seminars attendees.

Key Topics: Overview of the biogas industry in Europe and UK and its future development / New substrates and their pre-treatment for future biogas plants / Fundamentals of biological process / Choosing the right substrate and combining it for the optimal digestion input / Pre-treatment and pre-storage technology / Start-up phase and practical measures for monitoring the digestion process / Process parameters / Interactive group and laboratory session / Practical experiences and lessons from operating a biowaste and food waste plant / Measurement for process optimisation and enhancement of the biogas process / Visit of a biogas plant.

Contact: Mrs Silke Volk  Email: s.volk@biogas-zentrum.de   Tel: 0049 (0) 7954 921 969   Web: http://www.biogas-training.com  


Bespoke Training Opportunities

Bespoke training courses can be developed to individual client requirements. Please contact uwtc@abertay.ac.uk for further details. 

Expertise & Competencies

The University offers the following services to industry:

  • Biodegradability tests: Biochemical Methane Potential (BMP) assays
  • Feedstock characterisation and pre-treatment
  • Reactor and pilot-scale trials
  • Process design and modelling
  • Process monitoring and optimisation
  • Knowledge transfer and training, etc.
  • Bespoke training
  • Expertise / Consultancy