Enhanced biogas production and high-end valorization of digestate from anaerobic digestion of organic residuals

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According to Quebec Province's Climate Change Action Plan 2013-2020, all the organic residuals must be diverted from landfills and valorized. Hence, anaerobic digestion of the organic residuals has been adopted as one of the sustainable strategies to do so. The key organic residuals comprise municipal sludge and source-sorted organic waste (SSOW). Currently, the municipal sludge in Quebec City is handled by incineration and landfilling. Likewise, the SSOW derived from the food and beverages of municipal and industrial, commercial and institutional sectors is composted. However, these management options do not lead to efficient resource recovery causing greenhouse gas emissions. Moreover, municipal sludge and/or SSOW are a complex lignocellulosic matrix and it is difficult to use it directly for the anaerobic digestion. The anaerobic digestion entails soluble organic matter for efficient digestion to produce safe digestate and high biogas yield. To increase the solubility of sludge solids, pre-treatment techniques, such as ultrasonication, enzymatic treatment, addition of biochar and novel biochar enzyme microsystems and co-digestion with SSOW are proposed in this project. These pre-treatments can increase the solubility and/or decrease the inhibitors of the sludge/SSOW which can enhance the anaerobic digestion with corresponding increase in biogas yield. Further, addition of growth promoting microorganisms and biocontrol agents in a suitable proportion to the digestate might help the phosphorus, nitrogen and other nutrients fixation by plants and protection against agricultural pests, which can increase the market value of the digestate by 5-10 folds and can reduce the use of chemical fertilizers. Overall, use of anaerobic digestion technology is a sustainable method for reducing greenhouse gas emissions, odor, nutrient imbalance and carbon recycling making a clean, green, secure and sustainable environment for Canadians, strengthening the resilience to climate change. Further, the HQP will be trained in different disciplines of applied microbiology, wastewater engineering, environmental engineering, biochemical engineering and biochemistry.