Environmental Research Group for Resource Recovery, Department of Civil Engineering, Faculty of Engineering, Architecture and Science, Toronto Metropolitan University (formerly Ryerson University), 350 Victoria Street, Toronto, Ontario, M5B 2K3, Canada E-mail:
Department of Chemistry and Biology, Faculty of Science, Toronto Metropolitan University (formerly Ryerson University), 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada; Department of Microbiology, Stellenbosch University, Private Bag, XI, Matieland 7602, Stellenbosch, South Africa.
Water Sci Technol. 2022 Dec;86(12):3077-3092. doi: 10.2166/wst.2022.368.
Anaerobic digestion and fermentation processes in wastewater sludge treatment are limited by several factors, including the slow breakdown of complex organic matter and solubilization of solids. In this study, thermochemical pretreatment of thickened waste activated sludge using high temperature (>170 °C) was investigated to understand the impact of the pretreatment on the volatile fatty acids (VFA) production and its fractions during the fermentation process. Furthermore, the influence the thermochemical pretreatment on sludge disintegration and methane recovery was investigated. A range of acidic and alkaline conditions over the pH range of 4.5-10 was examined. Sludge (pH adjusted) was exposed to hydrothermal pretreatment (HTP) at a temperature of 170 °C for 30 min. Pretreated samples were then subjected to batch fermentation and methane potential tests which revealed that acidic and alkaline conditions resulted in increased sludge solubilization during HTP. Acidic conditions were associated with a higher VFA production yield of up to 185 mg chemical oxygen demand/g total chemical oxygen demand. Alkaline conditions led to a higher methane production yield where the maximum yield (276 mL CH/g total chemical oxygen demand) was found to occur at pH 10. Therefore, alkaline sludge used for fermentation has shown technical and economic feasibility for sludge carbon recovery.
在废水污泥处理中，厌氧消化和发酵过程受到多种因素的限制，包括复杂有机物的缓慢分解和固体的溶解。在这项研究中，使用高温（>170°C）对浓缩的废活性污泥进行热化学预处理，以了解预处理对发酵过程中挥发性脂肪酸（VFA）产生及其分数的影响。此外，还研究了热化学预处理对污泥解体和甲烷回收的影响。在 pH 值为 4.5-10 的范围内，考察了一系列酸性和碱性条件。将污泥（调节 pH 值）暴露于 170°C 的水热预处理（HTP）中 30 分钟。然后对预处理样品进行分批发酵和甲烷潜力测试，结果表明，在 HTP 过程中，酸性和碱性条件导致污泥的溶解增加。酸性条件与高达 185mg 化学需氧量/总化学需氧量的更高 VFA 产量有关。碱性条件导致更高的甲烷产量，在 pH 值为 10 时，最大产量（276mLCH/总化学需氧量）。因此，用于发酵的碱性污泥已显示出用于污泥碳回收的技术和经济可行性。
