Wastewater Treatment - Anaerobic Digestion
Low Temperature Anaerobic Digestion - Lab-scale (PhD work)
It is my vision that through the use of biological waste treatment methods we can solve sanitation issues globally and build a more sustainable society for the benefit of the environment and public health. In my research I have broadly looked to understand better the microbiology of anaerobic digestor systems. These systems employ the use of a mixed microbial population which produce methane and carbon dioxide as an end product. This methane gas is a potential source of renewable energy.
Why is this important?
Current wastewater treatment methods (activated sludge process for example) use a huge amount of energy (typically from fossil fuels), anaerobic digestion is a sustainable way to turn waste to energy.
Why "Low Temperature”?
The climate in Ireland, the UK and many parts of the world is primarily a cold climate. For many years it was assumed that for anaerobic digestion to work efficiently we needed to heat the reactor to 37 degrees Celsius or more. If we don’t need to do this, it is a waste of energy! In some cases, like for municipal wastewater (e.g. sewage) which is dilute and high volume the energy required to heat the reactor could not be recouped through potential methane production. Therefore, in my PhD work (at the Microbial Ecology Laboratory at the National University of Ireland Galway) I sought to understand the key stages of anaerobic digestion and the microbial community dynamics during long term (> 700 days) low temperature anaerobic digestion of a synthetic sewage wastewater. This was carried out using an innovative reactor design (designed by Dr Dermot Hughes and Prof. Vincent O’Flaherty).
What did we find?
New processes - anaerobic uptake of polyphosphate (important for resource recovery). Read more here!
That enhanced low-temperature hydrolytic and methanogenic activity occurred during low-temperature treatment of synthetic sewage. The response and development of the community was replicable within the reactors. Read more here!
That the source of microbial inoculum matters. Read more here!
Low Temperature Anaerobic Digestion - Scaled Up to Full-Scale by NVP Energy.
The Microbial Ecology Lab at NUI Galway Ireland has strong industrial connections and a history of demonstrating the feasibility of low temperature treatment of a range of wastewaters. This enabled a collaboration with NVP Energy and NUI Galway to research how to the scale up the reactor design used during my PhD. The scaled-up system has been successfully employed to treat industrial and municipal wastewater at ambient temperature. Read more here!
