College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, China.
Department of Environment and Safety, Taiyuan Institute of Technology, Taiyuan, China.
Sci Total Environ. 2022 Oct 1;841:156793. doi: 10.1016/j.scitotenv.2022.156793. Epub 2022 Jun 18.
Peracetic acid (PAA) is an emerging oxidant for waste activated sludge (WAS) treatment due to its strong oxidization and few toxic byproducts. Nitrite which can be in-situ recovered from WAS fermentation liquor, its protonated form (free nitrous acid, FNA) is regarded as the cost-effective inactivator. The stubborn extracellular polymeric substance (EPS) is the rate-limiting step for energy/resource recovery from WAS. This work found that the co-pretreatment of PAA and FNA can effectively promote short-chain fatty acids (SCFAs) production during anaerobic fermentation. Higher PAA dosage (100 mg/g VSS, FP4WAS) in co-pretreatment was beneficial for organics release (1976.9 mg COD/L), remarkably increased by 10.3- 96.5 % than that of low PAA dosage (25- 75 mg/g VSS), and promoted by 105.1 % and 62.1 % than FNA (FWAS)/PAA (100 mg/g VSS, P4WAS)-pretreated WAS. Effective release of soluble organics contributed to the SCFAs accumulation (7679 ± 86 mg COD/L, 4 d), enhanced by 200.0 % and 19.0 % than FWAS and P4WAS, respectively. Acetic (HAc) and propionic acid (HPr) peaked at 6344.7 mg COD/L in FP4WAS (accounted for 82.6 %), which increased by 10.6- 899.0 % than other groups. Moreover, OH and O were detected in co-pretreatment, may play the synchronous effect with the crucial intermediates of NO, NO and ONOO/ONOOH on EPS decomposition.
过氧乙酸（PAA）是一种新兴的废水处理氧化剂，因为它具有很强的氧化作用和很少的有毒副产物。亚硝酸盐可以从废水发酵液中就地回收，其质子化形式（游离亚硝酸，FNA）被认为是具有成本效益的失活剂。顽固的胞外聚合物（EPS）是从废水生物固体（WAS）中回收能源/资源的限速步骤。本工作发现，PAA 和 FNA 的联合预处理可以有效地促进厌氧发酵过程中短链脂肪酸（SCFAs）的生成。较高的 PAA 剂量（100mg/gVSS，FP4WAS）在联合预处理中有利于有机物的释放（1976.9mgCOD/L），比低 PAA 剂量（25-75mg/gVSS）提高了 10.3-96.5%，比 FNA（FWAS）/PAA（100mg/gVSS，P4WAS）预处理的 WAS 提高了 105.1%和 62.1%。可溶性有机物的有效释放有助于 SCFAs 的积累（4d 时为 7679±86mgCOD/L），比 FWAS 和 P4WAS 分别提高了 200.0%和 19.0%。在 FP4WAS 中，乙酸（HAc）和丙酸（HPr）的峰值分别达到 6344.7mgCOD/L（占 82.6%），比其他组分别增加了 10.6-899.0%。此外，在联合预处理中检测到 OH 和 O，它们可能与 NO、NO 和 ONOO/ONOOH 的关键中间体一起发挥同步作用，从而促进 EPS 的分解。
