Data_Sheet_1_The role of microbial ecology in improving the performance of anaerobic digestion of sewage sludge.DOCX

The use of next-generation diagnostic tools to optimise the anaerobic digestion of municipal sewage sludge has the potential to increase renewable natural gas recovery, improve the reuse of biosolid fertilisers and help operators expand circular economies globally. This review aims to provide perspectives on the role of microbial ecology in improving digester performance in wastewater treatment plants, highlighting that a systems biology approach is fundamental for monitoring mesophilic anaerobic sewage sludge in continuously stirred reactor tanks. We further highlight the potential applications arising from investigations into sludge ecology. The principal limitation for improvements in methane recoveries or in process stability of anaerobic digestion, especially after pre-treatment or during co-digestion, are ecological knowledge gaps related to the front-end metabolism (hydrolysis and fermentation). Operational problems such as stable biological foaming are a key problem, for which ecological markers are a suitable approach. However, no biomarkers exist yet to assist in monitoring and management of clade-specific foaming potentials along with other risks, such as pollutants and pathogens. Fundamental ecological principles apply to anaerobic digestion, which presents opportunities to predict and manipulate reactor functions. The path ahead for mapping ecological markers on process endpoints and risk factors of anaerobic digestion will involve numerical ecology, an expanding field that employs metrics derived from alpha, beta, phylogenetic, taxonomic, and functional diversity, as well as from phenotypes or life strategies derived from genetic potentials. In contrast to addressing operational issues (as noted above), which are effectively addressed by whole population or individual biomarkers, broad improvement and optimisation of function will require enhancement of hydrolysis and acidogenic processes. This will require a discovery-based approach, which will involve integrative research involving the proteome and metabolome. This will utilise, but overcome current limitations of DNA-centric approaches, and likely have broad application outside the specific field of anaerobic digestion.

利用下一代诊断工具优化市政污水污泥厌氧消化，有望提升可再生天然气回收效率、改善生物固体肥料的再利用，并助力全球运营者拓展循环经济。本综述旨在探讨微生物生态学（microbial ecology）在提升污水处理厂厌氧消化池运行性能中的作用，并强调系统生物学（systems biology）方法是监测连续搅拌反应器罐中温厌氧污水污泥的核心手段。我们进一步阐述了污泥生态学研究衍生出的潜在应用场景。厌氧消化的甲烷回收率提升或工艺稳定性优化（尤其是在预处理阶段或共消化过程中）的主要限制因素，是与前端代谢（水解与发酵）相关的生态学认知空白。诸如持续性生物起泡这类运行难题是核心问题，而生态学标志物（ecological markers）是解决该问题的适宜手段。但目前尚无生物标志物（biomarkers）可用于辅助监测与管控类群特异性起泡风险，以及污染物、病原体等其他风险。厌氧消化过程遵循基础生态学原理，这为预测和调控反应器运行功能提供了契机。将生态学标志物与厌氧消化的工艺终点及风险因素进行关联的未来路径，将依赖于数值生态学（numerical ecology）这一新兴领域——该领域利用源自α多样性、β多样性、系统发育多样性、分类学多样性、功能多样性的指标，以及基于遗传潜能推导的表型或生活史策略相关参数。与上述可通过全种群或个体生物标志物有效解决的运行问题不同，要实现功能的全面提升与优化，需强化水解与产酸过程。这需要采用基于发现的研究范式，开展涵盖蛋白质组（proteome）与代谢组（metabolome）的整合性研究。该研究路径将依托并突破现有以DNA为中心的研究方法的局限，且有望在厌氧消化以外的广泛领域得到应用。