Journal of Water Process Engineering
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2025
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IF 6.7
Ze-Tong Feng,Yan Yu,Ying-Jun Sun,Jia-Min Zhou,Xin Ma,Fei Ding,Yi-Liu Zheng,Ren-Cun Jin,Chun-Qiang Shen,Qian-Qian Zhang
This study systematically evaluated the effects of intermittent versus continuous addition of zero-valent iron (ZVI) as exogenous enhancers on nitrogen removal performance in denitrification systems. Results shown that under carbon-to‑nitrogen ratios (C/N) was 3, 2, and 1, continuous addition of ZVI significantly improved total nitrogen removal efficiency (TNRE) by 8.57 %, 19.34 %, and 11.45 %, respectively, compared to the control system. Concurrently, extracellular polymeric substance (EPS) production increased by 32.43 %, 62.91 %, and 35.93 %, to that of intermittent ZVI addition system at the same phases. The continuous ZVI-added system enriched more mixotrophic denitrification bacteria and increased soluble iron ion concentrations through EPS-mediated electron shuttling and endogenous protection mechanisms. While, under C/N was 0, the TNRE in continuously ZVI-added system reduced to 8.3 ± 3.24 % due to iron mineral crust formation. Specifically, the TNRE of system with intermittent addition of ZVI stabilized at 17.03 ± 3.24 %, enriched more autotrophic denitrification bacteria and avoided excessive accumulation of iron oxides. Therefore, this experiment provided new insights into the stable operation of the ZVI-enhanced denitrification process for treating low C/N wastewater.
研究领域:
环境科学
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微生物学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2020
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IF 7.864
Xiangyu Yang,Qiang He,Fucheng Guo,Xiaohui Sun,Junmao Zhang,Mengli Chen,Jan Vymazal,Yi Chen
Nanosized plastics (nanoplastics) releasing into the wastewater may pose a potential threat to biological nitrogen removal. Constructed wetland (CW), a wastewater treatment or shore buffer system, is an important sink of nanoplastics, while it is unclear how nitrogen removal in CWs occurs in response to nanoplastics. Here, we investigated the effects of polystyrene (PS) nanoplastics (0, 10, and 1000 μg/L) on nitrogen removal for 180 days in CWs. The results revealed that total nitrogen removal efficiency decreased by 29.5–40.6%. We found that PS penetrated the cell membrane and destroyed both membrane integrity and reactive oxygen species balance. Furthermore, PS inhibited microbial activity in vivo, including enzyme (ammonia monooxygenase, nitrate reductase, and nitrite reductase) activities and electron transport system activity (ETSA). These adverse effects, accompanied by a decline in the relative abundance of nitrifiers (e.g., Nitrosomonas and Nitrospira) and denitrifiers (e.g., Thauera and Zoogloea), directly accounted for the strong deterioration observed in nitrogen removal. The decline in leaf and root activities decreased nitrogen uptake by plants, which is an important factor of deterioration in nitrogen removal. Overall, our results imply that the presence of nanoplastics in the aquatic environment is a hidden danger to the global nitrogen cycle and should receive more attention.
研究领域:
环境科学
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生态学
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废水处理
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微生物学
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植物科学
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DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2019
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IF 6.97
Xiaonan Luo,Luwei Shen,Fangang Meng
Biorefractory humic substances (HS) that are ubiquitously present in nitrogen-rich wastewater streams, such as landfill leachate and livestock waste after anaerobic digestion, can potentially impact nitritation–anammox processes. In this study, multiple sequencing methods (e.g., 16S rRNA sequencing, clone library analysis, and metagenome sequencing) were employed to reveal the response of nitrosifying microbiota to HS at various concentrations (0–50 mg/L). Long-term reactor operation revealed that the nitrite yield was overall stable during all of the experimental days; however, fluctuations were observed as a result of sudden HS loads. The characterization by 16S rRNA sequencing indicated a decreased abundance of the phylum Proteobacteria (from 90.8% in HS0 to 52.1% in HS50) and an increased abundance of the phylum Bacteroidetes (from 4.7% in HS0 to 35.3% in HS50) upon exposure to HS. Both 16S rRNA sequencing and metagenome sequencing revealed that the family Nitrosomonadaceae, which was dominated by the genus Nitrosomonas, dramatically decreased, i.e., from ca. 70% in HS0 to ca. 40% in HS50. Both amoA-based clone libraries and metagenome sequencing suggested a substantial shift of AOB species, e.g., the emergence and enrichment of Nitrosomonas mobiliz upon exposure to HS. Interestingly, the amoABC gene was initially inhibited by 5 mg/L HS and then recovered at a higher level of HS (50 mg/L). In comparison, levels of hao gene were reduced with increasing HS (0, 5, and 50 mg/L). In addition, the abundance of genes assigned to membrane transport decreased after the addition of HS, and this reduction was likely associated with the electron shuttle roles of HS. Overall, the findings of this study provide insights into the response of core species and key genes to HS in nitritation systems.
研究领域:
环境微生物学
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废水处理工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
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IF 13.2
Quanhao Dou,Li Zhang,Yongzhen Peng
Mitigating the intense competition for substrates and ecological niches between heterotrophic and autotrophic microorganisms is essential for sustaining nitrogen removal in partial denitrification/anammox (PD/A) systems. Herein, an innovative high-intensity PD/A process was designed, utilizing iron sulfide and minimal organic carbon input. The nitrogen loading rate (NLR) reached 0.96 ± 0.06 kg N/(m 3 ·d) at a C/N ratio of 0.5, considerably higher than all results reported to date. Elucidating microbial ecology in this lab-scale mixotrophic PD/A system is vital for large-scale application. Results showed that sulfur-oxidizing denitrifiers ( Thiobacillus and Pseudorhodoplanes ; 0 % ∼ 1.11 %), functioning as network hubs, redistributed nitrate burden from heterotrophic denitrifiers ( Denitratisoma ; 8.44 %) via inorganic electron uptake, while freeing niches for the anammox bacteria ( Ca. Brocadia; 143.67-fold enrichment). A synergistic microbial community integrating multiple metabolic pathways achieved 96.24 ± 0.11 % nitrogen removal. Furthermore, genetic evidence indicated that membrane-bound narG accelerated nitrate reduction, while hydroxylamine-dependent anammox ( via hao instead of nirS ) eliminated toxic NO intermediates. This enhanced bioreactor stability and reduced hydraulic retention time from 12 h to 2 h, maximizing NLR. Our findings propose a novel paradigm to advance PD/A systems toward low-carbon, high-rate operation, ensuring desirable effluent quality and microbial ecological balance.
研究领域:
环境生物技术
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微生物生态学
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污水处理
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反应器工程
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氮循环
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功能基因组学
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产品关联
DOI
高影响因子
ENVIRONMENTAL RESEARCH
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2023
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IF 8.3
Shuai Zhang,Junfeng Su,Shuyu Liu,Yi Ren,Shumiao Cao
There is an urgent demand to investigate mechanisms for the improvement of denitrification in carbon-deficient environment, which will effectively reduce the eutrophication in water bodies polluted by nitrate. In this study, denitrifying bacterium Comamonas sp. YSF15 was used to explore the differences in different carbon source concentrations, with the complete genome, metabolomics, and other detecting methods. Results showed that strain YSF15 was able to achieve efficient denitrification, with complete pathways for denitrification and central carbon metabolism. The carbon deficiency prompted the bacteria to use extracellular amino acid-like metabolites initially, to alleviate inhibition and maintain bioactivity , which also facilitated glycogen storage. The biogenic inhibitors (tautomycin, navitoclax, and glufosinate) at extremely low level potentially favored the competitiveness and intraspecific utilization of extracellular polysaccharides (PS). Optimal solutions for bioaggregation in carbon-deficient condition are achieved by regulating the hydrophobicity , and hydrogen bond in extracellular metabolites. The strategy contributes to the maintenance of bioactivity and adaptation to carbon deficiency. Overall, this study provides a new perspective on understanding the denitrification strategies in carbon-deficient environment, and helps to improve the nitrate removal in low-carbon wastewater treatment .
研究领域:
环境微生物学
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废水处理
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代谢组学
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基因组学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
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2021
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IF 6.498
Zhi-Ling Li,Di Cao,Cai-Hua Bai,Xiao-Jing Yao,Xiao-Qiu Lin,Si-Pei Wang,Jun Nan,Bin Liang,Li-Wei Li,Kai Sun,Ai-Jie Wang
The response of the denitrification community to long-term antibiotic exposure requires further investigation. Here, the significantly altered denitrifying community structure and function were observed by continuous exposure to 1 mg/L sulfamethoxazole (SMZ) or chlortetracycline (CTC) for 180 d in the expanded granular sludge bed reactors. Thaurea , positively correlated with SMZ and NO 3 − removal efficiency ( NrE ), was highly enriched in the SMZ-added reactor, while, Comamons and Acinetobacter were largely inhibited. The acute inhibited and then gradual-recovered NrE (87.17–90.38 %) was observed with highly expressed narG , indicating the adaptability of Thaurea to SMZ. However, the abundance of Thaurea and Comamonas greatly decreased, while Melioribacter and Acinetobacter were largely enriched in the CTC-added reactor. CTC created more serious and continuous inhibition of NO 3 − reduction ( NrE of 64.53–66.95 %), with lowly expressed narG . Improved NO 2 − reduction capacity was observed in both reactors (70.16–95.42 %) with highly expressed nirS and nosZ , revealing the adaptability of NO 2 − reduction populations to antibiotics.
研究领域:
环境微生物学
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生物技术
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污水处理
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产品关联
DOI
PubMed
高影响因子
DESALINATION
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2024
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IF 8.3
Xiaojing Zhang,Yujia Guo,Bingbing Ma,Ang Gao,Jiahui Nie,Chenyu Jia,Peng Zhou,Yongpeng Ma
Naproxen (NPX) has been frequently detected in various nitrogenous wastewaters and been proved have significant impact on nitrogen removal systems. Completely autotrophic nitrogen removal over nitrite (CANON) process was one of the most economical nitrogen removal technologies and has good application prospect. However, whether it was suitable for treating NPX containing wastewater was still unclear. This study investigated the migration of NPX in CANON process by adopting a membrane bioreactor (MBR), and analyzed its impact on the nitrogen removal and microbial characteristics by suppling incremental NPX. The results showed the NPX supplied in 0.001 to 1000 μg L −1 was mainly bio-adsorbed by the sludge, which then led to continuous suppression on anaerobic ammonium-oxidizing bacteria (AAOB) and decreased the TN removal from 79.1 % to 50.6 %. Additionally, the activity of hydroxylamine oxidoreductase and nitrite oxidoreductase enzymes both decreased. However, the abundance of AAOB and the functional gene hzsB initially increased as a stress response. Ammonia-oxidizing bacteria (AOB) were slightly impacted and then adapted, with the amoA gene amplifying 2.3 times and the abundance of Nitrosomonas increasing from 2.4 % to 4.0 %. Nitrite-oxidizing bacteria (NOB) were significantly enhanced, leading to an increase in effluent nitrate concentration from 34.7 to 101.6 mg L −1 , and in the abundance of Nitrospira from 2.2 % to 13.5 %. The enhancement in NOB significantly limited the AAOB activity in return via competing nitrite, and further limited the TN removal. Denitrifying bacteria experienced only slight impact, with the expression of narG , nirK , and nirS genes slightly fluctuated. It is essential to thoroughly washout NOB and introduce additional strategy for enhancing NPX biodegradation for stable operation of the CANON process when treating NPX containing wastewater.
研究领域:
环境工程
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微生物学
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污水处理
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DOI
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Peng Wang,Chen Zhu,Yingji Gao,Zhonghua Cai,Ye ye,Yi Tao
Nitrate-driven sulfide oxidation has been proven to be a cost-effective approach for controlling sediment odor. However, injecting liquid nitrate (LN) directly into sediment carries ecological risks of nitrate escape and release of pollutants into overlying water. In this study, slow-release nitrate granules (GN) were prepared and applied in a continuous flow reactor to assess the differences between GN and LN in sediment remediation and control of this ecological risk. The results showed that the GN slowly released calcium nitrate, resulting in a decrease in acid volatile sulfide (AVS) from an initial 1328 ± 42.7 mg/kg to 490 ± 341 and 212 ± 32.8 mg/kg in the upper (U) and deeper (D) layers of the sediment, respectively. No significant decrease in AVS concentrations was observed in the LN treatments. Compared with LN-D and -U, the NH 4 + -N production and PO 4 3- -P release doses were reduced by 29.5% and 52.0% for GN-D and 41.2% and 37.8% for GN-U, respectively. Taxonomic analysis showed that sulfide-driven denitrifiers such as Thiobacillus , Rhodanobacter , Sulfurimonas , and Pseudomonas became dominant in the GN treatments, which were 2.8–6.7, 27.0–201.8, 1.5–3.0, and 3.0–496 times that of the LN treatments, respectively. The abundance of sulfur oxidation genes (e.g., sat and aprB ) and denitrifying genes (e.g., nirS and nosZ ) were also upregulated to higher levels by GN. Moreover, the genes (e.g., nrfA ) responsible for the isomerization of nitrate into ammonium were down-regulated by GN. The results showed that the slow-released calcium nitrate should be a promising way for in-situ remediation of sulfide-rich sediment.
研究领域:
环境科学
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微生物学
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沉积物修复
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水处理
✓ 已验证
产品关联
DOI
高影响因子
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