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

根据魁北克省《2013-2020年气候变化行动计划》，所有的有机残留物必须从垃圾填埋场转移出来并进行回收。因此，有机残留物的厌氧消化已被采用为可持续发展的策略之一。主要的有机残留物包括城市污泥和源分类有机废物（SSOW）。目前，魁北克市的城市污泥采用焚烧和填埋的方式处理。同样，从市政和工业、商业和机构部门的食品和饮料中提取的SSOW是堆肥。然而，这些管理办法不能有效地回收资源，造成温室气体排放。此外，城市污泥和/或SSOW是一种复杂的木质纤维素基质，很难直接用于厌氧消化。厌氧消化需要有效消化的可溶性有机物，以产生安全的消化物和高沼气产量。为了提高污泥固体的溶解度，本项目提出了超声处理、酶处理、添加生物炭和新型生物炭酶微系统以及与SSOW共消化等预处理技术。这些预处理可以增加污泥/SSOW的溶解度和/或减少抑制剂，从而增强厌氧消化，相应增加沼气产量。此外，在消化液中添加适当比例的促生微生物和生物防治剂，有助于植物对磷、氮等营养物质的固定和农业害虫的防治，可使消化液的市场价值提高5-10倍，并可减少化肥的使用。总的来说，利用厌氧消化技术是一种可持续的方法，可以减少温室气体排放、气味、营养失衡和碳循环，为加拿大人创造一个清洁、绿色、安全和可持续的环境，增强对气候变化的适应能力。此外，HQP将接受应用微生物学、废水工程、环境工程、生化工程和生物化学等不同学科的培训。

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.