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132 results on '"ZHOU Aijuan"'

114. Microbial network for waste activated sludge cascade utilization in an integrated system of microbial electrolysis and anaerobic fermentation

Author

Liu, Wenzong, He, Zhangwei, Yang, Chunxue, Zhou, Aijuan, Guo, Zechong, Liang, Bin, Varrone, Cristiano, Wang, Ai‑Jie, Liu, Wenzong, He, Zhangwei, Yang, Chunxue, Zhou, Aijuan, Guo, Zechong, Liang, Bin, Varrone, Cristiano, and Wang, Ai‑Jie

Abstract

Background: Bioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved in an integrated system of microbial electrolysis cell (MEC) and anaerobic digestion (AD) for waste activated sludge (WAS). Microbial communities in integrated system would build a thorough energetic and metabolic interaction network regarding fermentation communities and electrode respiring communities. The characterization of integrated community structure and community shifts is not well understood, however, it starts to attract interest of scientists and engineers. Results: In the present work, energy recovery and WAS conversion are comprehensively affected by typical pretreated biosolid characteristics. We investigated the interaction of fermentation communities and electrode respiring communities in an integrated system of WAS fermentation and MEC for hydrogen recovery. A high energy recovery was achieved in the MECs feeding WAS fermentation liquid through alkaline pretreatment. Some anaerobes belonging to Firmicutes (Acetoanaerobium, Acetobacterium, and Fusibacter) showed synergistic relationship with exoelectrogensin the degradation of complex organic matter or recycling of MEC products (H2). High protein and polysaccharide but low fatty acid content led to the dominance of Proteiniclasticum and Parabacteroides, which showed a delayed contribution to the extracellular electron transport leading to a slow cascade utilization of WAS. Conclusions: Efficient pretreatment could supply more short-chain fatty acids and higher conductivities in the fermentative liquid, which facilitated mass transfer in anodic biofilm. The overall performance of WAS cascade utilization was substantially related to the microbial community structures, which in turn depended on the initial pretreatm

Published
2016

117. Erratum to: Enhanced short chain fatty acids production from waste activated sludge conditioning with typical agricultural residues: carbon source composition regulates community functions

Author

Guo, Zechong, primary, Zhou, Aijuan, additional, Yang, Chunxue, additional, Liang, Bin, additional, Sangeetha, Thangavel, additional, He, Zhangwei, additional, Wang, Ling, additional, Cai, Weiwei, additional, Wang, Aijie, additional, and Liu, Wenzong, additional

Published
2016
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126. Effects of temperature on hydrolysis performance and short-chain fatty acids production during thermophilic micro-aerobic fermentation of waste activated sludge.

Author

Yang, Chunxue, He, Zhangwei, Guo, Zechong, Zhou, Aijuan, Wang, Aijie, and Liu, Wenzong

Subjects
ACTIVATED sludge process, HYDROLYSIS, FATTY acid synthesis, THERMOPHILIC bacteria, FERMENTATION, TEMPERATURE effect, CHEMICAL oxygen demand
Abstract

Rapid hydrolysis of waste activated sludge (WAS) can be achieved by improving activities of extracellular enzymes under proper temperature conditions. As short-chain fatty acids (SCFAs) accumulation is always consumed by methanogens under anaerobic conditions, and considering that the micro-aerobic condition can inhibit the activities of methanogens, in this study, effects of temperature (55–75°C) on thermophilic micro-aerobic fermentation of WAS were investigated. Results showed that the highest soluble chemical oxygen demand (SCOD) yield was obtained at 60°C (4,407 ± 80 mg/L, 36 h), 2.0 times higher than that obtained at 75°C (2,180 ± 40 mg/L, 36 h), the corresponding hydrolysis rate was 0.6689 d−1. The highest SCFAs yield was 2,928 ± 12 mg COD/L at 60°C and 36 h, 4.9 times higher than that obtained at 75°C (594 ± 10 mg COD/L, 36 h). The analysis of SCFAs composition showed that acetic acid (HAc) accounted for the most percentage (>40%), followed by n-valeric (n-HVa) (20–25%), and propionic acids (HPr) (10–15%). Total suspended solids removal efficiency reached 18.7% after 192-h fermentation at 60°C. These results suggested that the optimal thermophilic micro-aerobic conditions for WAS hydrolysis and SCFAs accumulation from WAS were 60°C and 36-h fermentation time. [ABSTRACT FROM AUTHOR]

Published
2016
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130. Upgrading VFAs bioproduction from waste activated sludge via co-fermentation with soy sauce residue

Author

Duan, Yanqing, Zhou, Aijuan, Wen, Kaili, Liu, Zhihong, Liu, Wenzong, Wang, Aijie, and Yue, Xiuping

Abstract

Conditioning of extra carbon sources has been widely reported to facilitate fermentation of waste activated sludge (WAS). Soy sauce residue (SSR) was a relatively untapped carbon source for sludge conditioning. This batch study aimed to evaluate the possible implementation of SSR for volatile fatty acids (VFAs) production from WAS. To upgrade the bioavailability of feedstock, three typical pretreatment methods were conducted, i.e., ammonium hydroxide (AH), sulfuric acids (SA) and thermal assisted alkaline (TA). AH pretreated test (AH-PT) outperformed due to a relatively strong structure decomposition of cellulosic materials as revealed by infrared spectroscopic analysis and crystal index. As a result, performed a high hydrolysis rate of 4449 mg COD/d, 1.12-1.23-fold higher than that in TA and SA pretreated tests (TA-PTand SA-PT), and 7.8-fold higher than that in the Control test. Meanwhile, a volatile fatty acids (VFAs) contribution of 401.2 mg COD/g SSR∙L and a maximum acidification rate of 3.59 d–1was recorded, with a high sum proportion of mall molecular acetic and propionic 82.2%, 11%–70% increase over the other three tests. Besides, speciation process characterized with functional genus differentiation was identified by microbial diversity and distribution investigation and canonical correspondence analysis (CCA). Finally, a potential market value of 0.49–0.65 Billion €/year was preliminary estimated, showing promise of resource recovery from both WAS and SSR instead of extensive disposal.

Published
2019
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131. NiRu-Mo 2 Ti 2 C 3 O 2 as an efficient catalyst for alkaline hydrogen evolution reactions: the role of bimetallic site interactions in promoting Volmer-step kinetics.

Author

Xi Q, Xie F, Sun Z, Liu J, Zhang X, Wang Y, Zhou A, Ma X, Gao X, Yue X, Ren J, Fan C, Jian X, and Li R

Abstract

The Volmer step in alkaline hydrogen evolution reactions (HERs), which supplies H* to the following steps by cleaving H-O-H bonds, is considered the rate-determining step of the overall reaction. The Volmer step involves water dissociation and adsorbed hydroxyl (*OH) desorption; Ru-based catalysts display a compelling water dissociation process in an alkaline HER. Unfortunately, the strong affinity of Ru for *OH blocks the active sites, resulting in unsatisfactory performance during HER processes. Hence, this study investigates a series of key descriptors (Δ G *H 2 O , Δ G *H-OH , Δ G *H , and Δ G *OH ) of TM (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, or Pt)-Ru/Mo 2 Ti 2 C 3 O 2 to systematically explore the effects of bimetallic site interactions on the kinetics of the Volmer step. The results indicate that bimetallic catalysts effectively reduced the strong adsorption of *OH on Ru sites; especially, the NiRu diatomic state shows the highest electron-donating ability, which promoted the smooth migration of *OH from Ru sites to Ni sites. Therefore, Ru, Ni and MXenes are suitable to serve as water adsorption and dissociation sites, *OH desorption sites, and H 2 release sites, respectively. Ultimately, NiRu/Mo 2 Ti 2 C 3 O 2 promotes Volmer kinetics and has the potential to improve alkaline HERs. This work provides theoretical support for the construction of synergistic MXene-based diatomic catalysts and their wide application in the field of alkaline HERs.

Published
2024
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132. Improving the short-chain fatty acids production of waste activated sludge stimulated by a bi-frequency ultrasonic pretreatment.

Author

Zhou A, Yang C, Kong F, Liu D, Chen Z, Ren N, and Wang A

Subjects
Carbohydrate Metabolism, Carbohydrates chemistry, Fatty Acids, Volatile chemistry, Hydrogen-Ion Concentration, Proteins chemistry, Proteins metabolism, Ultrasonics, Water Pollutants, Chemical chemistry, Fatty Acids, Volatile metabolism, Sewage
Abstract

Short-chain fatty acids (SCFAs) are the most important intermediate in the waste activated sludge (WAS) fermentation process. This work explored a novel approach to improve the SCFAs production from WAS. Experimental results showed that the disintegration and acidification of WAS were enhanced markedly by using bi-frequency (28+40 kHz) ultrasonic pretreatment compared with monofrequency (28 kHz and 40 kHz) ultrasonic pretreatments. After 28 + 40 kHz ultrasonic pretreatment, the SCOD concentration increased from original 363 mg COD l(-1) to 10810 mg COD l(-1) which was 1.53-fold and 1.44-fold of the values obtained with 28kHz and 40kHz ultrasonic pretreatments, respectively. The maximum SCFAs production reached 7587 mg COD l(-1) in the 28 + 40 kHz test which was respectively 1.25-fold and 1.31-fold of that in the 28 kHz (6053 mg COD l(-1)) and 40 kHz (5809 mg COD I(-1)) tests. This was the highest SCFAs production obtained so far using WAS, pretreated by ultrasonic technology, as the renewable carbon source. SCFAs composition analysis revealed there was more acetic acid (3992 mg COD l(-1), accounted for 52.6% of the total SCFAs) for the 28+40 kHz ultrasonic pretreatment which was beneficial to many subsequent bioprocesses.

Published
2013

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