Anaerobic digestion is a well-established method of stabilizing various organic wastes. However, effective and low-cost methods need to be developed and applied for digestate management to realize the full benefits of anaerobic digestion. The post-treatment of the digestate does not only reduce the greenhouse gas emissions due to storage or land application of digestates but also leads to an increase in the recovery of methane. The objective of this study was to quantify anaerobic treatability and biogas formation from the digestates of three full-scale anaerobic digesters fed with fruit processing and brewery wastewater and animal manure and food waste. Biochemical methane potential assays were conducted to determine the residual biogas production and yields achievable in the digestate samples investigated. The methane yields for the digestates investigated ranged between 0.055 and 0.147 l CH₄/g VS which agree well with the relevant values from the literature. Anaerobic treatability assessment of digestates indicated chemical oxygen demand (COD), total solids (TS), and volatile solids (VS) removals of up to 62, 35, and 41%, respectively. Very low removals were observed for nitrogen and phosphorus as expected. The total potential energy yield and electricity production based on anaerobic digestion of the digestates of the three full-scale digesters are calculated as 35.3 GJ/day and 3.4 MWh, respectively. Moreover, a significant reduction in the greenhouse gas production will be achieved by anaerobically digesting the digestates of the three full-scale anaerobic digesters investigated in this study. If these findings are projected for all 127 biogas systems in Michigan, the significance of digestate treatment and valorization becomes clearer.

Graphical abstract

中文翻译：

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厌氧后的可处理性和消化液的残余沼气潜力

厌氧消化是稳定各种有机废物的成熟方法。但是，需要开发有效且低成本的方法并将其用于消化管理，以实现厌氧消化的全部益处。消化液的后处理不仅减少了由于消化液的存储或土地施用而导致的温室气体排放，而且还导致了甲烷回收率的提高。这项研究的目的是从三个全规模厌氧消化池的消化物中量化厌氧可处理性和沼气的形成，这些消化池供以水果加工和啤酒废水以及动物粪便和食物垃圾。进行了生化甲烷潜力测定法，以确定所研究的消化样品中残留的沼气产量和可达到的产量。₄/ g VS与文献中的相关值非常吻合。消化液的厌氧可处理性评估表明，化学需氧量（COD），总固体（TS）和挥发性固体（VS）的去除率分别高达62％，35％和41％。如预期的那样，氮和磷的去除率非常低。基于三个厌氧消化池消化物的厌氧消化的总潜在能量产量和发电量分别计算为35.3 GJ /天和3.4 MWh。此外，通过厌氧消化该研究中研究的三个全规模厌氧消化池的消化物，将实现温室气体生产的显着减少。如果将这些发现用于密歇根州的所有127个沼气系统，

图形概要