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，所有有机残留物必须从垃圾填埋场转移出来并进行有价处理。因此，有机残留物的厌氧消化已被采用为可持续的战略之一。主要有机残留物包括城市污泥和来源分类的有机废物(SOW)。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SOW也被堆肥。然而，这些管理选择并不能有效回收造成温室气体排放的资源。此外，城市污泥和/或固体废弃物是一种复杂的木质纤维基质，很难直接用于厌氧消化。厌氧消化需要可溶的有机物，以便有效地消化，产生安全的消化产物和高沼气产量。为提高污泥固形物的溶解度，本项目提出了超声波处理、酶处理、添加生物炭和新型生物炭酶微系统以及与SOW共消化等前处理技术。这些前处理可以增加污泥/固体废物的溶解度和/或减少抑制剂，从而在促进厌氧消化的同时相应地增加沼气产量。此外，在沼泽地中添加适当比例的促生菌和生防剂，可促进植物对磷、氮等营养物质的固定和对农业病虫害的防治，可使沼泽地的市场价值提高5-10倍，并可减少化肥的使用。总体而言，使用厌氧消化技术是减少温室气体排放、气味、营养失衡和碳循环的可持续方法，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还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.