EREF Scholar 2016
Enhanced Deligninification and Methane Generation in Waste Repositories through In-Situ Techniques – Overcoming Heterogeneity
In municipal solid waste (MSW) landfills, the production of methane is negligible at first, this is followed by a sharp increase in the rate of generation, which then leads to a ‘long tail’ of gradual methane generation towards the end. At this stage, it is difficult to capture the methane produced due to its low concentrations and it cannot be used to generate energy. Therefore, it is either flared or allowed to escape into the environment. This problem is very important to solve as the accelerated climate change, in part, has been caused due to methane emissions from landfills around the world.
For over 20 years, there has been strong evidence of peroxidase enzymes to have a remarkable ability to degrade lignin. The focus of Syed’s research is to use such peroxidase enzyme-enhanced lixiviants in MSW landfills to facilitate in-situ lignocellulose degradation and explore mechanisms to overcome waste heterogeneity. In-situ amendment of landfills has been largely restricted to leachate recirculation, but this is presumably affected by the heterogeneity of the waste and preferential flow. A key determinant of success in achieving accelerated MSW degradation in-situ is the ability to understand, control and minimize the impact of the heterogeneous nature of landfill waste on recovery.
The overall aim is to accelerate and increase MSW delignification, the total methane yield and prevent the ‘long tail’ of low levels of methane escape to the atmosphere, providing environmental and economic benefits with reduced liabilities for repository operators.
Project’s main objectives:
- Exploration and enhancement of in-situ deligninification of MSW using enzymatic methods.
- Establish model lignin-containing wastes and exploring deligninification rates under ideal experimental conditions. These will then be used to model ideal methane generation rates both with and without enzymatic methods.
- The effect of flow heterogeneity on deligninification rates will be explored and used in models to determine effect on overall methane generation over time (comparison to the above point and actual methane data would be carried out). Small-scale column tests will be employed to assess fluid transport through and between different waste size fractions tested in parallel, in a controlled model of heterogeneous material.
- The development of models for resource mobilization and transport within and from waste repositories will be carried out. These models will then be applied to investigate the optimization of the recovery technique.
Syed is a BEng Civil Engineering (Year in Industry) graduate about to begin his Ph.D. studies at Cardiff University. As part of his industrial placement, he acquired experience in both commercial management and academic research. At Barratt-David Wilson (BDW) Homes, he enjoyed spending time on-site with technical managers and quantity surveyors. He found the application of engineering principles in practice to be inspirational. Similarly, his numerical modeling research work on the ‘In-Situ Processes in Resource Extraction from Waste Repositories’ (INSPIRE) project allowed him to further develop his interpersonal skills and provided a creative environment to fulfill his project goals with his team. It was here that he developed the idea of taking on lignin-rich compounds in landfills for his dissertation in the following year.
Syed was also awarded a WastePack Bursary earlier in 2016 by the Chartered Institution of Wastes Management (CIWM) which allowed him to attend the CIWM annual conference in London. He received the opportunity to write an article related to his dissertation for the CIWM Autumn 2016 newsletter. Additionally, he was awarded a ‘Cardiff University Undergraduate Research Opportunities Programme’ (CUROP) project in early 2016 and worked as an undergraduate researcher for the summer at Cardiff University’s BRE Trust Centre for Sustainable Engineering.
He wishes to one day become a lecturer-researcher in waste management and continue to apply his acquired engineering knowledge and experience in solving real-life problems for a more sustainable future. After all, in the words of the late American cosmologist Carl Sagan; “To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we’ve ever known.”
Muaaz-Us-Salam, S., Cleall, P. J., & Harbottle, M. J. (2019). The case for examining fluid flow in municipal solid waste at the pore-scale – A review. Waste Management & Research. https://doi.org/10.1177/0734242X19828120
Muaaz-Us-Salam, S., Cleall, P.J., Harbottle, M.J., (2017). Enhanced Delignification and Methane Generation in Waste Repositories – Overcoming Heterogeneity, 16th International Waste Management and Landfill Symposium. CISA, Sardinia, Italy.