Article
Agricultural Engineering
Kun Wang, Chuanting Zhou, Hua Zhou, Ming Jiang, Guang Chen, Cong Wang, Zhenjian Zhang, Xiaodan Zhao, Lu-Man Jiang, Zhen Zhou
Summary: A comparative study was conducted on the AAO process and its two upgrading processes, five-stage Bardenpho and AAO + MBBR, using long-term operation data of six full-scale wastewater treatment plants. The three processes showed good performance in COD and phosphorus removal. The Bardenpho process was advantageous in nitrogen removal, while the AAO + MBBR had higher microbial richness and diversity. Both processes had specific bacteria enrichment and were suitable for different upgrading purposes.
BIORESOURCE TECHNOLOGY
(2023)
Article
Agricultural Engineering
Jiao Wang, Yongzhen Peng, Qiong Zhang, Yunlong Su, Shuying Wang, Jianwei Li
Summary: This study investigates the NH2OH dosing strategy for nitrogen removal in a continuous-flow A(n)OAO reactor using real municipal wastewater. High nitrite accumulation ratio of 98% is achieved within two days by continuously adding 10 mg/L NH2OH. By reducing the dosing frequency gradually, the effluent total nitrogen concentration can reach as low as 4.8 +/- 2.2 mg N/L with a removal efficiency of 88.7 +/- 5.3%.
BIORESOURCE TECHNOLOGY
(2022)
Article
Agricultural Engineering
Susan N. James, Arya Vijayanandan
Summary: An anoxic-aerobic-anoxic process was established in a sequencing batch reactor to simultaneously remove organic carbon and nitrogen from wastewater. The study found that the optimum conditions for the process were achieved with a dissolved oxygen level of 1.5 mg/L and 1 hour pre-anoxic and post-anoxic periods. Under these conditions, the removal efficiencies of TOC, NH4+-N, and TN were 98.76%, 98.52%, and 88.23% respectively. Breakpoints in the pH, DO, and ORP curves provided insights into the biochemical reactions occurring in the reactor. Inhibition studies revealed that nitrogen removal pathways such as heterotrophic nitrification or direct conversion contributed to the removal of 27.69% of NH4+-N, while aerobic denitrification accounted for the removal of 20.55% of TN. Microbial community analysis confirmed the presence of heterotrophic nitrifiers and aerobic denitrifiers. The study emphasized the benefits of the varied redox conditions provided by limited aeration for nitrogen removal, leading to reduced energy usage and operating costs.
BIORESOURCE TECHNOLOGY
(2022)
Article
Environmental Sciences
S. Nivedhita, P. Shyni Jasmin, M. Sarvajith, Y. V. Nancharaiah
Summary: The formation, performance, and microbial community structure of aerobic granular sludge (AGS) were investigated in the presence and absence of oxytetracycline (OTC). The results showed that the addition of OTC promoted the formation of well-settling AGS, but decreased the removal rates of nitrogen and phosphorus. This study is important for understanding the impact of antibiotics on AGS and designing treatment methods for antibiotic-laden wastewaters.
Article
Environmental Sciences
Lin Wang, Bingrong Li, Yongmei Li, Jianmin Wang
Summary: The study found that specific nitrification and denitrification rates increased under low dissolved oxygen conditions, with a decrease in the oxygen half saturation constant for both ammonia oxidizing bacteria and nitrite oxidizing bacteria. The observed yield coefficients also increased, along with higher relative abundances of AOB, NOB, and denitrifiers detected through high-throughput sequencing. Improved simultaneous nitrification and denitrification under low DO conditions contributed to enhanced nitrogen removal.
Article
Environmental Sciences
Liru Fan, Hong Yao, Shihai Deng, Fangxu Jia, Weiwei Cai, Zhifeng Hu, Jianhua Guo, Huan Li
Summary: The SF-A/OA/O process has demonstrated superior performance in full-scale coking wastewater treatment compared to the A/O/O process, showing efficient removal of COD, NH4+-N, TN, phenols, and cyanide. The abundance and structure of the microbial community may be key factors contributing to the strong stability of the SF-A/OA/O system.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Agricultural Engineering
Jing Wang, Hui Wang, Ruina Zhang, Liu Wei, Ruijie Cao, Luochun Wang, Ziyang Lou
Summary: This study revealed that the expression of enzymes has significant impact on the performance of leachate treatment plants, especially on the nitrification process. The activity of nitrogen-metabolizing enzymes decreases with the increase of influent total nitrogen, leading to nitrification failures. Additionally, the decrease in carbon/nitrogen ratio weakens the activity of denitrifying enzymes. The decrease in influent chemical oxygen demand may result in the decrease or disappearance of certain microbial communities, indicating high loading operation.
BIORESOURCE TECHNOLOGY
(2022)
Article
Environmental Sciences
Yumiao Lu, Wenlong Zhang, Yi Li, Chi Zhang, Longfei Wang, Lihua Niu, Huanjun Zhang
Summary: This study aims to determine the microbial assemblage and functional patterns under black carbon addition, and found that the nitrate removal efficiency of modified black carbon system achieved 46.44%. The deterministic process dominated the assemblage of community, with key taxa like Sulfuricella, Allorhizobium, and Nitrospira stimulating the shift of community composition regarding nitrogen removal.
ENVIRONMENTAL RESEARCH
(2021)
Article
Agricultural Engineering
Qianzhi Wang, Yunhao Pan, Guangyu Chu, Shuailing Lu, Zhiming Zhang, Yangguo Zhao, Chunji Jin, Mengchun Gao
Summary: This study investigated the performance, microbial community, and functional genes of a sequencing batch biofilm reactor (SBBR) in treating mariculture wastewater under different aerobic/anoxic alternation numbers. The removal efficiency of COD and NH4+-N remained high, while the TN removal efficiency gradually decreased with the increase of aerobic/anoxic alternation number. The microbial diversity and abundance were significantly affected by the variation of aerobic/anoxic alternation number.
BIORESOURCE TECHNOLOGY
(2023)
Article
Engineering, Environmental
Donghui Liang, Yongyou Hu, Ruzhen Huang, Jianhua Cheng, Yuancai Chen
Summary: The selective inhibitory effects of various antibiotics on aerobic nitrogen removal were investigated, showing different removal efficiencies and degradation pathways for different antibiotics. High-throughput sequencing revealed that aerobic denitrifying, recalcitrant pollutant degrading, and antibiotic-resistant bacteria dominate during the community evolution process.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Engineering, Chemical
Yanhu Wu, Xiang Li, Yongkang Wang, Bingtao Liu
Summary: In this study, the effect of different temperatures on simultaneous nitrogen and phosphorus removal was investigated using simulated domestic wastewater. It was found that temperatures above 23 degrees C significantly improved the removal rates of NH4+-N, chemical oxygen demand, total nitrogen, and total phosphorus. Microbial community analysis revealed that bacteroidetes and proteobacteria played a crucial role in simultaneous nitrogen and phosphorus removal.
DESALINATION AND WATER TREATMENT
(2022)
Article
Engineering, Environmental
Vicente Elicio P. S. G. da Silva, Silvio Luiz de Sousa Rollemberg, Andre Bezerra dos Santos
Summary: Aerobic granular sludge (AGS) systems were evaluated for the simultaneous removal of carbon, nitrogen, and phosphorous in leachate treatment. Among the different reactor configurations, the O/An with step-feeding reactor (R4) showed the highest biomass retention, nitrification rate, and removal of COD, total nitrogen, and total phosphorous.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Environmental Sciences
Huoqing Wang, Li Li, Yuepeng Sun
Summary: In a lab-scale constant-flow multiple anoxic and aerobic process, nitrogen removal and nitrous oxide (N2O) emission were investigated with the addition of suspended carriers. The study found that efficient removal of ammonia nitrogen and orthophosphate was achieved, but N2O emission occurred during nitrification and denitrification, especially with the coexistence of heterotrophic activities. Nitrite played a crucial role in N2O emission, and specific microbial communities were identified as responsible for N2O emission during nitrification and denitrification, providing guidance for controlling N2O emission in the multiple AO process design.
WATER AIR AND SOIL POLLUTION
(2021)
Article
Environmental Sciences
Shuang Liu, Fan Wu, Mingzhu Guo, Ming Zeng, Wei Liu, Zhiqiang Wang, Nan Wu, Jingguo Cao
Summary: This study reveals the potential of innovative biological nitrogen removal (BNR) processes such as simultaneous nitritation, anammox and denitrification (SNAD), partial nitritation anammox (PNA), and partial denitrification anammox (PDA) in reducing nitrous oxide (N2O) emissions compared to traditional processes through extensive big data statistical analysis. Machine learning models and correlation analysis further support these findings.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Rui Yang, Lin-jiang Yuan, Ru Wang, Zhi-xian He, Lin Lei, Yan-chen Ma
Summary: This study investigates the production process of nitrous oxide (N2O) in the aerobic zone of nitrogen bio-removal process by measuring the activities of two key denitrifying enzymes. The results demonstrate that most of the N2O released and produced come from autotrophic denitrification, while heterotrophic denitrification acts as an N2O consumer. The study suggests that reducing autotrophic denitrification is the best way to reduce N2O production in the aerobic phase.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Zhongzhong Wang, Shun Wang, Sihuang Xie, Yan Jiang, Jizhong Meng, Guangxue Wu, Yuansheng Hu, Xinmin Zhan
Summary: The study found that the addition of biochar has a slight increase in specific methane yield in dry anaerobic digestion, especially in the degradation of poorly biodegradable organics. However, the supplementation of biochar did not significantly affect the peak methane production rate, possibly due to the important role of enhancing electron transfer mechanism.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Qiannan Guo, Qidong Yin, Jin Du, Jiane Zuo, Guangxue Wu
Summary: This study investigated the system performance and microbial characteristics in anaerobic reactors with different operating modes and sludge retention times using the r/K selection theory. The results showed that the microbial community abundance and methane production were significantly impacted by different operating conditions in the reactors.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Environmental
Tianqi Zhang, Zhaolu Feng, Yunhong Shi, Qidong Yin, Guangxue Wu
Summary: This study investigated the removal of ammonium nitrogen under microacrobic or anoxic conditions using a continuous-flow biofilm reactor. The results showed a high removal rate and percentage of NH4-N after long-term operation. Through batch experiments and metagenomics analysis, the main microorganisms related to nitrogen metabolism were identified, and a potential oxygen-producing microorganism was discovered. The findings suggest that the removal of NH4-N under oxygen-limited conditions might involve interactions among different microorganisms, which warrants further investigation.
JOURNAL OF ENVIRONMENTAL ENGINEERING
(2022)
Article
Agricultural Engineering
Jin Du, Qidong Yin, Xingzhao Zhou, Qiannan Guo, Guangxue Wu
Summary: This study evaluated the cross-feeding function by analyzing microbial aggregates in anaerobic digesters and found complementary genetic potential for amino acid synthesis between syntrophs and methanogens, implying potential cross-feeding partnership.
BIORESOURCE TECHNOLOGY
(2022)
Article
Engineering, Environmental
Zhongzhong Wang, Shun Wang, Yuansheng Hu, Bang Du, Jizhong Meng, Guangxue Wu, He Liu, Xinmin Zhan
Summary: The shift from acetoclastic to hydrogenotrophic pathway in methanogenesis under ammonia inhibition is a common phenomenon. This study investigated the ammonia tolerance and recovery of acetoclastic and hydrogenotrophic methanogens in anaerobic digestion. The results showed that hydrogenotrophic methanogens had higher tolerance to ammonia than acetoclastic methanogens, but were more adversely affected by NH4+ at pH≤8.0.
Article
Engineering, Chemical
Qidong Yin, Guangxue Wu, Piet N. L. Lens
Summary: This study investigates the impact of acidogenic microorganisms and environmental factors on the production of volatile fatty acids (VFAs) and alcohols. The microbial communities and metabolic potential were analyzed using high-throughput sequencing, revealing the importance of core features and their response to environmental changes. The electrode potential was found to be the most significant environmental variable affecting the distribution of core features and fermentation pathways.
Article
Environmental Sciences
Xinyue Ma, Ziyan Cheng, Wenjing Bai, Rui Tang, Guangxue Wu, Xinmin Zhan, Zhen-Hu Hu
Summary: Intensive animal farming generates a large volume of digested liquid, and excessive application can lead to pollution of surface water and groundwater. This study investigates the use of Ca(ClO)2 pretreatment to enhance SS flocculation removal in digested dairy wastewater. Results show that Ca(ClO)2 pretreatment combined with PAC flocculation can effectively remove SS and improve the removal of chemical oxygen demand and phosphorus.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Agricultural Engineering
Bang Du, Mengqi Gu, Zhenhu Hu, Xinmin Zhan, Guangxue Wu
Summary: Anaerobic ethanol oxidation can be thermodynamically unfavourable under standard conditions, but can become exergonic with extracellular electron transfer (EET) through microbial redox-active proteins (RAP). This study evaluates the thermodynamic effects of the fraction of substrate degraded through EET, product feedback, distribution of electrons from EET between acetotrophic and hydrogenotrophic methanogenesis, and the redox potential of RAP on anaerobic ethanol oxidation. The results show that ethanol oxidation can occur when the redox potential is above -0.408 V with EET or when product concentration is below a certain threshold. The appropriate redox potential ranges for active acetotrophic and hydrogenotrophic methanogens were determined. The EET fraction and electron distribution were found to be key factors in maintaining biomass yields and influencing the ratio of methanogens.
BIOMASS & BIOENERGY
(2023)
Review
Green & Sustainable Science & Technology
Zhongzhong Wang, Yuansheng Hu, Shun Wang, Guangxue Wu, Xinmin Zhan
Summary: The dry anaerobic digestion (AD) process is a promising technology for the treatment and stabilization of high-solid organic waste, with advantages such as higher methane yield and reduced digester size. However, it still faces challenges due to the excessive solids content and differences from wet AD in terms of operation and design. It is important to understand the characteristics of dry AD, analyze operational factors, and evaluate optimization methods to develop practical applications.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2023)
Article
Agricultural Engineering
Jin Du, Xingzhao Zhou, Qidong Yin, Jiane Zuo, Guangxue Wu
Summary: This study explores the effects of operational parameters on microbial communities in anaerobic digestion (AD) with sulfate. It finds that reactors in rapid-filling mode exhibit fast kinetic properties, while reactors in slow-filling mode can mitigate propionate accumulation. Taxonomic and functional analysis further support the suitability of rapid- and slow-filling modes for the growth of r-strategists (such as Desulfomicrobium) and K-strategists (such as Geobacter), respectively.
BIORESOURCE TECHNOLOGY
(2023)
Article
Environmental Sciences
Bang Du, Zhongzhong Wang, Piet N. L. Lens, Xinmin Zhan, Guangxue Wu
Summary: This study investigated the performance, syntrophic relationships, microbial communities, and metabolic pathways of ethanol-fed reactors with different operational modes and solids retention times. The results showed that different microorganisms were enriched under different SRT conditions, and syntrophic bacteria related to methane production could be enriched under low SRT conditions.
ENVIRONMENTAL RESEARCH
(2024)
Article
Engineering, Environmental
Wenjing Bai, Rui Tang, Guangxue Wu, Wei Wang, Shoujun Yuan, Liwen Xiao, Xinmin Zhan, Zhen-Hu Hu
Summary: This study investigated the distribution of heavy metals in suspended solids (SS) and their influence on co-precipitation during struvite recovery from digested swine wastewater. The results showed that the concentration of heavy metals in the wastewater ranged from 0.05 to 17.05 mg/L. During struvite generation, 56.9-80.3% of individual heavy metals were co-precipitated. These findings provide a potential way for controlling the co-precipitation of heavy metals in struvite.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Engineering, Environmental
Wenjing Bai, Rui Tang, Guangxue Wu, Wei Wang, Shoujun Yuan, Liwen Xiao, Xinmin Zhan, Zhen-Hu Hu
Summary: Struvite recovered from wastewater contains significant amounts of fecal indicator bacteria, porcine adenoviruses, and antibiotic resistance genes, which can pose potential risks. This study investigated the co-precipitation behavior of these pathogens and genes with suspended solids (SS) and found that high-density SS contributed more to the co-precipitation than low-density SS. Furthermore, the presence of SS in struvite hindered the inactivation of bacteria and genes during drying. These findings suggest that removing high-density SS prior to struvite recovery can effectively control the co-precipitation and inactivation of pathogens and genes.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Biotechnology & Applied Microbiology
Yuyin Wang, Guangxue Wu
Summary: Antibiotics like tetracycline in wastewater can lead to operational failure of anaerobic digestion systems, inhibiting COD removal, causing VFAs accumulation, reducing methane production, and impacting microbial communities. CFRs performed better in COD shock loading recovery, propionate degradation, and methane production. Additionally, CFRs exhibited superior tetracycline removal capacity compared to SBRs. Biodegradation was found to be the primary pathway for tetracycline removal, and long-term tetracycline exposure affected archaea abundances and enrichment of hydrolytic-acidogenic bacteria. CFRs provided a more conducive environment for the enrichment of these microorganisms.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2023)
Article
Engineering, Environmental
Bang Du, Xinmin Zhan, Piet N. L. Lens, Yifeng Zhang, Guangxue Wu
Summary: Efficient anaerobic digestion relies on the cooperation of different microorganisms with different metabolic pathways. This study investigated the effects of different operational modes and the addition of powdered activated carbon (PAC) on ethanol metabolic pathways. The results showed that the SBR mode and the presence of CO2 facilitated ethanol metabolism towards propionate production, while the CFR mode with extended solids retention time enriched Geobacter. Adjusting operational modes and PAC addition can modulate anaerobic ethanol metabolism and enrich Geobacter.
