Beginning of this year the lipid-team from the WOW! project started to work on the process enabling the selection of bacteria responsible for lipid accumulation from municipal sewage. What are the first results?
The lab-experiments in bioreactors allowed to determine first key parameters (such as wastewater composition and aeration mode) to select corresponding bacteria. Preliminary results showed that a sensible growth of accumulating bacteria is favorable when specific intermitted aerobic/anaerobic mode conditions together with adapted Sludge Age and Hydraulic Retention Time are ensured.
Other scenarios (dissolved oxygen concentration, sludge loading, feeding regime and temperature) including parallel tests with real sewage are in the pipeline.
Alongside, the analytical subcontractor (Luxembourg Institute of Science and Technology) is developing the extraction protocol for the evaluation of sewage and sludge matrices in terms of lipid content and quantification of long-chain fatty acids for expected biodiesel yield and its quality. Longer saturated fatty acids are in fact excellent for biodiesel production, whereas unsaturated fatty acids are great for cold weather biodiesel production, therefore a mixture is desirable.
The picture on the right was taken by Aurelie Couvidat, University of Luxembourg.