Techniques for enhanced anaerobic digestion and bioenergy conversion of pulp and paper sludge

加拿大是世界上最大的森林产品出口国。因此，加拿大与森林相关的工业，如纸浆和造纸厂，在该国经济中发挥着重要作用。大多数P&P厂采用物理处理和好氧生物工艺来处理废水，产生大量污泥。加拿大的工厂每年产生200多万干吨污泥，比该国每年的市政废水污泥产量还要多。工厂目前的污泥管理做法是成本和能源密集型的，并对环境造成负面影响，包括对垃圾填埋场或泻湖排放温室气体的重大贡献。另一种污泥管理方案是实施厌氧消化(AD)工艺，用于P&P污泥的生物能量转化。AD是一个将有机物转化为富含甲烷的沼气和肥料的生化过程。该技术已被广泛应用于各种有机废物，但由于其复杂的物理化学成分限制了AD的性能，因此对P&P污泥的研究较少。拟议的研究计划将研究不同的技术，包括水热预处理(HTP)、厌氧共消化(AnCoD)和两级AD工艺，以克服P&P污泥厌氧消化所面临的主要挑战。本研究的具体目标包括i)研究单独的水热预处理和在外部导电材料存在的情况下对P&P污泥特性(如有机增溶)和后续AD的生物能量回收、有机物去除和消化特性的影响；ii)研究工艺改进并通过两级AD工艺从P&P污泥同时生产生物氢和生物甲烷；iii)研究P&P污泥在AnCoD过程中的长期性能，并评估原料特性、混合比例和微生物群落的影响。这一研究项目的成功预计将在较长期内为加拿大创造主要的绿色能源收入，因为它专注于从有机废物中生产可再生能源。参与该项目的高素质人员(HQP)将出色地利用女王大学的跨学科研究和教育机构美丽之水研究中心的独特能力。他们将对用于有机废物处理和能源回收的先进生物工艺工程有深入的了解。他们还将在各种生物反应器的设计和操作中获得动手实验，并培养各种先进分析技术的技能。这种培训将使他们能够在绿色化学工程和废物管理日益增长的领域的工业或学术界获得有价值的职业。

Canada is the world's largest exporter of forest products. As a result, Canada's forest-related industry, such as pulp and paper (P&P) mills, plays a significant role in the Country's economy. Most P&P mills employ physical treatment and aerobic biological processes to treat their wastewater, generating large amounts of sludge. Canadian mills generate over 2 million dry tons of sludge every year, which is greater than the Country's annual municipal wastewater sludge production. The current sludge management practices in mills are cost and energy-intensive and pose negative environmental impacts, including a significant contribution to greenhouse gas emission from landfills or lagoons. An alternative sludge management option is implementing an anaerobic digestion (AD) process for bioenergy conversion of P&P sludge. AD is a biochemical process converting organics into methane-rich biogas and fertilizer. This technology has been widely used for various organic waste but received little attention for P&P sludge due to its complex physio-chemical compositions limiting the performance of AD. The proposed research program will investigate different techniques, including hydrothermal pre-treatment (HTP), anaerobic co-digestion (AnCoD), and a two-stage AD process to overcome the major challenges confronting anaerobic digestion of P&P sludge. The specific objectives of this research include i) To investigate the effects of hydrothermal pre-treatment individually and in the presence of external conductive materials on P&P sludge characteristics (e.g., organic solubilization) and on the performance of the subsequent AD in terms of bioenergy recovery, organics removal, and digestate characteristics, ii) To investigate process improvement and simultaneous production of biohydrogen and biomethane from P&P sludge via two-stage AD process, iii) To study the long-term performance and evaluate the effects of feedstock characteristics, mixing ratios, and microbial community during AnCoD of P&P sludge, food waste, and manure. The success of this research program will be expected to create major green energy revenues in the longer-term in Canada as it focuses on renewable energy production from organic waste. The highly qualified personnel (HQP) involved in this program will make excellent use of the unique capabilities of The Beaty Water Research Centre, an interdisciplinary research and education facility at Queen's University. They will develop a deep understanding of advanced bioprocess engineering for organic waste treatment and energy recovery. They will also gain hands-on experiments in various bioreactors' design and operation and develop skills in various advanced analytical techniques. This training will enable them to have rewarding careers in industry or academia in the growing areas of green chemical engineering and waste management.