Xie Jiaqian, Xin Xiaodong, Ai Xiaohuan, Hong Junming, Wen Zhidan, Li Wei, Lv Sihao
Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR. China; Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, PR. China.
Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR. China; Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, PR. China.
Water Res. 2022 Nov 1;226:119287. doi: 10.1016/j.watres.2022.119287. Epub 2022 Oct 22.
Enhancing anaerobic treatment efficiency of waste activated sludge (WAS) toward preferable resource recovery would be an important requirement for achieving carbon-emission reduction, biosolids minimization, stabilization and security concurrently. This study demonstrated the synergic effect of potassium ferrate (PF) and nitrite on prompting WAS solubilisation and acidogenic fermentation toward harvesting volatile fatty acids (VFAs). The results indicated the PF+NaNO co-pretreatment boosted 7.44 times and 1.32 times higher WAS solubilisation [peak soluble chemical oxygen demand (SCOD) of 2680 ± 52 mg/L] than that by the single nitrite- and PF-pretreatment, respectively, while about 2.77 times and 2.11 times higher VFAs production were achieved (maximum VFAs accumulation of 3536.25 ± 115.24 mg COD/L) as compared with the single pretreatment (nitrite and PF)-fermentations. Afterwards the WAS dewaterability was improved simultaneously after acidogenic fermentation. Moreover, a schematic diagram was established for illustrating mechanisms of the co-pretreatment of PF and nitrite for enhancing the VFAs generation via increasing key hydrolytic enzymes, metabolic functional genes expression, shifting microbial biotransformation pathways and elevating abundances of key microbes in acidogenic fermentation. Furthermore, the mechanistic investigations suggested that the PF addition was conducive to form a relatively conductive fermentation environment for enhancing electron transfer (ET) efficiency, which contributed to the VFAs biotransformation positively. This study provided an effective strategy for enhancing the biodegradation/bioconversion efficiency of WAS organic matters with potential profitable economic returns.
提高废弃活性污泥（WAS）的厌氧处理效率以实现更好的资源回收，将是同时实现碳减排、生物固体最小化、稳定化和安全性的一项重要要求。本研究证明了高铁酸钾（PF）和亚硝酸盐在促进WAS溶解和产酸发酵以收获挥发性脂肪酸（VFAs）方面的协同作用。结果表明，与单一亚硝酸盐预处理和PF预处理相比，PF + NaNO联合预处理使WAS溶解率分别提高了7.44倍和1.32倍[峰值可溶性化学需氧量（SCOD）为2680±52 mg/L]，而与单一预处理（亚硝酸盐和PF）发酵相比，VFAs产量分别提高了约2.77倍和2.11倍（最大VFAs积累量为3536.25±115.24 mg COD/L）。产酸发酵后，WAS的脱水性能同时得到改善。此外，还建立了一个示意图，以说明PF和亚硝酸盐联合预处理通过增加关键水解酶、代谢功能基因表达、改变微生物生物转化途径以及提高产酸发酵中关键微生物的丰度来增强VFAs生成的机制。此外，机理研究表明，添加PF有利于形成相对导电的发酵环境，以提高电子传递（ET）效率，这对VFAs生物转化有积极贡献。本研究为提高WAS有机物的生物降解/生物转化效率提供了一种有效的策略，并具有潜在的可观经济回报。
