Fundamental studies of solar photocatalytic pathways for valorization of biosolids to fuels and chemicals

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With the growing concern over climate change and the global depletion of energy and natural resources, there is a pressing need for rapid shift to renewable sources of energy and chemicals. Meanwhile, the ongoing surge in the planet's urban populations and modernization has resulted in the ever increasing production of biosolids that are often disposed as waste. However, these biosolids are renewable sources of organic matter and can be converted to energy and valuable chemicals. In Canada, wastewater treatment plants produce in excess of 660,000 dry tonnes of biosolids per year and this amount is expected to increase as new and upgraded facilities are constructed under the Canada-wide Strategy for the Management of Municipal Wastewater Effluent ratified by the Canadian Council of Ministers of the Environment (CCME) in 2009. More recently, in 2012, CCME approved a new national policy that requires the beneficial use of valuable resources in municipal biosolids. A similar trend is observed elsewhere in the world. The total sludge production in 15 European Union countries increased by about 50% from 1984 and reached 10 M t/year in 2010, and in China wastewater treatment plants are expected to generate 10 M t/year biosolids by 2015. Therefore, extracting value from biosolids through conversion to biofuels and bio-based chemicals will reduce waste and lower the overall greenhouse gas emissions. ******In recent years, production of transportable fuels using solar energy (S2F) via photocatalytic conversion of biomass has gained increasing attention and interest. Although solar photocatalysis has been studied intensively for pollutant abatement and contaminant mineralization, its application in storing sunlight energy in the form of chemical bonds is new. In this project, we aim to examine the utility of solar photocatalysis in valorizing municipal and industrial biosolids. Specific objectives of this research are: 1) to design novel visible light photocatalysts for the optimum production of hydrogen and value-added chemicals, 2) to develop a better fundamental understanding of mechanisms and kinetics of solar photocatalytic processes for the conversion of municipal and industrial biosolids, and 3) to engineer novel photo-reactors for maximum solar energy harvesting. ******Solar photocatalytic conversion of biosolids has the potential to radically change the wastewater treatment industry by extracting value from solid waste materials and enhancing the energy efficiency of the treatment plant. This technology will result in improving the health of the environment as mandated by CCME and will contribute to the long-term energy supply and security in Canada. It will also help Canada secure a leading position in the emerging low-carbon economy and achieve its greenhouse gas emission targets.**