Shanghai Academy of Environmental Sciences, Shanghai 200233, China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China.
Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Bioresour Technol. 2024 Jun;401:130748. doi: 10.1016/j.biortech.2024.130748. Epub 2024 Apr 26.
Greenhouse gas (GHG) emissions from biological treatment units are challenging wastewater treatment plants (WWTPs) due to their wide applications and global warming. This study aimed to reduce GHG emissions (especially NO) using a gas circulation strategy in a closed sequencing-batch reactor when the biological unit varies from activated sludge (AS) to aerobic granular sludge (AGS). Results show that gas circulation lowers pH to 6.3 ± 0.2, facilitating regular granules but elevating total NO production. From AS to AGS, NO emission factor increased (0.07-0.86 %) due to decreasing ammonia-oxidizing rates while the emissions of CO (0.3 ± 0.1 kg-CO/kg-chemical oxygen demand) and CH remained in the closed biosystem. The gas circulation decreased NO emission factor by 63 ± 15 % after granulation higher than 44 ± 34 % before granulation, which is implemented by heterotrophic denitrification. This study provides a feasible strategy to enhance heterotrophic NO elimination in the biological WWTPs.
温室气体（GHG）排放的生物处理装置是具有挑战性的废水处理厂（WWTPs），由于其广泛的应用和全球变暖。本研究旨在减少温室气体排放（尤其是氮）使用气体循环策略在封闭序列批式反应器时，生物单元从活性污泥（AS）到好氧颗粒污泥（AGS）变化。结果表明，气体循环降低 pH 值至 6.3 ± 0.2，有利于常规颗粒，但提高总氮的产量。从 AS 到 AGS，由于氨氧化速率降低，NO 排放因子增加（0.07-0.86%），而 CO（0.3 ± 0.1 kg-CO/kg-化学需氧量）和 CH 的排放量在封闭生物系统中保持不变。在颗粒化后，NO 排放因子降低了 63±15%，而在颗粒化前则降低了 44±34%，这是通过异养反硝化实现的。本研究为增强生物 WWTP 中的异养硝酸盐消除提供了一种可行的策略。
