State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
Sci Total Environ. 2019 Jun 15;669:600-607. doi: 10.1016/j.scitotenv.2019.03.175. Epub 2019 Mar 13.
Short-chain fatty acids (SCFAs) as recoverable carbon source from waste activated sludge anaerobic fermentation process have aroused wide concern. In this study, free nitrous acid (FNA) and freezing pretreatments were combined to enhance SCFAs yield and fermented sludge dewaterability in the anaerobic fermentation system. The effects of different FNA concentrations and different freezing conditions (with or without curing stages) were analysed and compared. The results indicated that combining 1.07 mg N/L FNA with 48 h continuous freezing at -5 °C, raised SCFAs production from 6.7 mg COD/g volatile suspended solids (VSS) for the blank (no pretreatment) up to 124.0 mg COD/g VSS. In addition, the minimal water content of the treated fermented sludge cake was 78.11%, which was less than that of the blank (81.22%). SCFAs production and dewaterability enhancement could be attributed to sludge disintegration induced by the co-pretreatment, which led to sludge solubilisation, organics release, methanogenesis inhibition and particle size variation. This study implied that FNA and freezing co-pretreatment has the potential to enhance SCFAs production and sludge dewaterability in wastewater treatment plants.
短链脂肪酸（SCFAs）作为从废活性污泥厌氧发酵过程中回收的碳源引起了广泛关注。在这项研究中，结合游离亚硝酸（FNA）和冷冻预处理来提高厌氧发酵系统中 SCFAs 的产量和发酵污泥的脱水性能。分析和比较了不同 FNA 浓度和不同冷冻条件（有无固化阶段）的影响。结果表明，将 1.07mgN/L 的 FNA 与 -5°C 下连续冷冻 48h 相结合，可将空白（无预处理）条件下的 SCFAs 产量从 6.7mgCOD/g 挥发性悬浮固体（VSS）提高到 124.0mgCOD/gVSS。此外，处理后的发酵污泥饼的最小含水量为 78.11%，低于空白（81.22%）。SCFAs 产量和脱水性能的提高可归因于联合预处理诱导的污泥解体，导致污泥溶解、有机物释放、甲烷生成抑制和颗粒尺寸变化。本研究表明，FNA 和冷冻联合预处理有可能提高污水处理厂中 SCFAs 的产量和污泥的脱水性能。
