Pub Date : 2026-04-01Epub Date: 2026-01-29DOI: 10.1016/j.biortech.2026.134121
Yu Chen , Jianfeng Ye , Hong Liu , Wenxuan Jiang , Feng Hu , Zuxin Xu
Trace organic micropollutants (OMPs) in wastewater treatment plant (WWTP) effluents pose ecological risks, while cost-effective removal strategies using constructed wetlands (CWs) remain unclear. This study investigated a multi-stage wetland system using spectroscopic and molecular-level indicators to link pollutant removal, dissolved organic matter (DOM) transformation, and biotoxicity. Biological Oxidation Pond (BOP), Subsurface Flow Wetland (SSFW), and Surface Flow Wetland (SFW) contributed 25.00%, 25.00%, and 50.00% of chemical oxygen demand (COD) removal, respectively, with overall inhibition rates below 10% and nearly zero after SSFW. DOM fluorescence intensity decreased by 23.44%, and Specific Ultraviolet Absorbance at 254 nm (SUVA254), modified Aromaticity Index (AImod), formulas containing C, H, O, and N or S (CHON/CHOS) revealed compositional and toxicity-related changes. SSFW removed protein-like DOM, while SFW targeted humic-like fractions; ceramsite outperformed zeolite in SSFW. Sedimentation Tank (ST) and Deep Purification Pond (DPP) were redundant, whereas the “BOP-SSFW-SFW” configuration achieved advanced purification and biotoxicity control.
{"title":"Full-scale analysis of dissolved organic matter in multi-stage wetlands treating wastewater treatment plant effluent and optimization of treatment process","authors":"Yu Chen , Jianfeng Ye , Hong Liu , Wenxuan Jiang , Feng Hu , Zuxin Xu","doi":"10.1016/j.biortech.2026.134121","DOIUrl":"10.1016/j.biortech.2026.134121","url":null,"abstract":"<div><div>Trace organic micropollutants (OMPs) in wastewater treatment plant (WWTP) effluents pose ecological risks, while cost-effective removal strategies using constructed wetlands (CWs) remain unclear. This study investigated a multi-stage wetland system using spectroscopic and molecular-level indicators to link pollutant removal, dissolved organic matter (DOM) transformation, and biotoxicity. Biological Oxidation Pond (BOP), Subsurface Flow Wetland (SSFW), and Surface Flow Wetland (SFW) contributed 25.00%, 25.00%, and 50.00% of chemical oxygen demand (COD) removal, respectively, with overall inhibition rates below 10% and nearly zero after SSFW. DOM fluorescence intensity decreased by 23.44%, and Specific Ultraviolet Absorbance at 254 nm (SUVA<sub>254</sub>), modified Aromaticity Index (AImod), formulas containing C, H, O, and N or S (CHON/CHOS) revealed compositional and toxicity-related changes. SSFW removed protein-like DOM, while SFW targeted humic-like fractions; ceramsite outperformed zeolite in SSFW. Sedimentation Tank (ST) and Deep Purification Pond (DPP) were redundant, whereas the “BOP-SSFW-SFW” configuration achieved advanced purification and biotoxicity control.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134121"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-02-11DOI: 10.1016/j.biortech.2026.134137
Yingfei Sun , Yijiao Chang , Yuxuan Wang , Zuohong Chen , Zhu Liang , Jiao Chen , Bing Li , Yongcheng Wang , Xiao-yan Li , Lin Lin
Sludge dewatering is vital for reducing volume and energy consumption, yet traditional chemical conditioners are limited by cost and environmental concerns. Herein, a green fungal flocculant was developed by cultivating Aspergillus niger using food waste hydrolysate as the sole substrate, achieving a biomass yield of 140.3 mg/g-chemical oxygen demand. Alkaline modification effectively altered surface chemistry by degrading hydrophilic amide groups, enhancing hydrophobicity, surface charge repulsion, and hyphal dispersion. When applied as a coagulant aid with 3% FeCl3, the base-modified fungal flocculant markedly improved sludge dewatering, increasing Dx(90) from 102.0 to 1542.9 μm and reducing specific resistance to filtration by 75.7%, with a final cake water content of 56.8%. Mechanistic analyses revealed that improved fungal network porosity, enhanced hydrophobic interactions, and coordination between fungal functional groups and Fe3+ ions synergistically facilitated water release. This bio-based strategy offers a sustainable alternative that simultaneously valorizes food waste and replaces synthetic polymeric flocculants in sludge treatment.
{"title":"Green flocculant of Aspergillus niger fungus cultured from food waste hydrolysate for enhanced sludge dewatering","authors":"Yingfei Sun , Yijiao Chang , Yuxuan Wang , Zuohong Chen , Zhu Liang , Jiao Chen , Bing Li , Yongcheng Wang , Xiao-yan Li , Lin Lin","doi":"10.1016/j.biortech.2026.134137","DOIUrl":"10.1016/j.biortech.2026.134137","url":null,"abstract":"<div><div>Sludge dewatering is vital for reducing volume and energy consumption, yet traditional chemical conditioners are limited by cost and environmental concerns. Herein, a green fungal flocculant was developed by cultivating <em>Aspergillus niger</em> using food waste hydrolysate as the sole substrate, achieving a biomass yield of 140.3 mg/g-chemical oxygen demand. Alkaline modification effectively altered surface chemistry by degrading hydrophilic amide groups, enhancing hydrophobicity, surface charge repulsion, and hyphal dispersion. When applied as a coagulant aid with 3% FeCl<sub>3</sub>, the base-modified fungal flocculant markedly improved sludge dewatering, increasing Dx(90) from 102.0 to 1542.9 μm and reducing specific resistance to filtration by 75.7%, with a final cake water content of 56.8%. Mechanistic analyses revealed that improved fungal network porosity, enhanced hydrophobic interactions, and coordination between fungal functional groups and Fe<sup>3+</sup> ions synergistically facilitated water release. This bio-based strategy offers a sustainable alternative that simultaneously valorizes food waste and replaces synthetic polymeric flocculants in sludge treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134137"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-02-11DOI: 10.1016/j.biortech.2026.134209
Baodan Jin , Yeyu Yan , Zhixuan Bai , Hua He , Jingjing Du , Yuanqian Xu , Chuang Ma , Lan Wang , Jiantao Ji
To enhance the performance of endogenous partial denitrification (EPD) systems, different iron valence states (nano-zero-valent iron (nZVI), Fe(II), and Fe(III)) were introduced, and their effects on microbial communities and metabolic pathways were investigated using metagenomics. The results indicated that iron supplementation significantly improved the removal of COD, NO3−-N, and PO43−-P, as well as NO2−-N accumulation. Notably, Fe(III) proved most effective, achieving a NO2−-N accumulation of 27.7 ± 3.7 mg/L and a PO43−-P removal efficiency of 64.7 ± 7.5%, whereas excessive Fe(II) and Fe(III) (40 mg/L) inhibited NO2−-N accumulation. While the overall microbial community structure remained stable, iron addition enriched specific denitrifying and phosphorus-accumulating genera such as Candidatus Competibacteraceae (1.36%, 2.40%, 2.30%), Candidatus Competibacter (0.40%, 0.65%, 0.62%), and Thauera (3.02%, 1.76%, 3.00%). nZVI promoted carbon utilization and denitrification gene expression, enhanced the including endogenous carbon transformation and nitrogen metabolism. In contrast, Fe(II) and Fe(III) enhanced NO2−-N accumulation by suppressing key genes (nirS/nirK, norB, nosZ) and shifted phosphorus metabolism toward chemical removal as the dominant pathway. Exogenous iron optimizes the performance of the EPD system by downregulating iron metabolism genes (afuA, fbpA, and afu) to mitigate iron toxicity stress. These findings provide theoretical support for optimizing EPD systems and improving nutrient removal in wastewater treatment.
{"title":"Metagenomics reveals the mechanisms of endogenous partial denitrification (EPD) driven by different valence iron states:Nitrite accumulation, microbial adaptation, functional gene and metabolic pathways","authors":"Baodan Jin , Yeyu Yan , Zhixuan Bai , Hua He , Jingjing Du , Yuanqian Xu , Chuang Ma , Lan Wang , Jiantao Ji","doi":"10.1016/j.biortech.2026.134209","DOIUrl":"10.1016/j.biortech.2026.134209","url":null,"abstract":"<div><div>To enhance the performance of endogenous partial denitrification (EPD) systems, different iron valence states (nano-zero-valent iron (nZVI), Fe(II), and Fe(III)) were introduced, and their effects on microbial communities and metabolic pathways were investigated using metagenomics. The results indicated that iron supplementation significantly improved the removal of COD, NO<sub>3</sub><sup>−</sup>-N, and PO<sub>4</sub><sup>3−</sup>-P, as well as NO<sub>2</sub><sup>−</sup>-N accumulation. Notably, Fe(III) proved most effective, achieving a NO<sub>2</sub><sup>−</sup>-N accumulation of 27.7 ± 3.7 mg/L and a PO<sub>4</sub><sup>3−</sup>-P removal efficiency of 64.7 ± 7.5%, whereas excessive Fe(II) and Fe(III) (40 mg/L) inhibited NO<sub>2</sub><sup>−</sup>-N accumulation. While the overall microbial community structure remained stable, iron addition enriched specific denitrifying and phosphorus-accumulating genera such as <em>Candidatus Competibacteraceae</em> (1.36%, 2.40%, 2.30%), <em>Candidatus Competibacter</em> (0.40%, 0.65%, 0.62%), and <em>Thauera</em> (3.02%, 1.76%, 3.00%). nZVI promoted carbon utilization and denitrification gene expression, enhanced the including endogenous carbon transformation and nitrogen metabolism. In contrast, Fe(II) and Fe(III) enhanced NO<sub>2</sub><sup>−</sup>-N accumulation by suppressing key genes (<em>nirS/nirK</em>, <em>norB</em>, <em>nosZ</em>) and shifted phosphorus metabolism toward chemical removal as the dominant pathway. Exogenous iron optimizes the performance of the EPD system by downregulating iron metabolism genes (<em>afuA</em>, <em>fbpA</em>, and <em>afu</em>) to mitigate iron toxicity stress. These findings provide theoretical support for optimizing EPD systems and improving nutrient removal in wastewater treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134209"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-26DOI: 10.1016/j.biortech.2026.134099
Xing Cai , Chuang Liu , Sida Fu , Wansheng Shi , Zhenxing Huang , Mingxing Zhao
This study compared the treatment of high-salinity pharmaceutical wastewater by using Continuous Stirred Tank Reactor (CSTR), Upflow Anaerobic Sludge Blanket (UASB), and two-phase Cascade Energy Anaerobic Reactor (CEAR) with bioaugmentation (Bacillus altitudinis K3). The CEAR significantly increased methane production through separating acidogenic and methanogenic phases, achieving a 9.70% to 23.10% higher methane content than other systems. With the increase in salinity and organic loading rate, the chemical oxygen demand (COD) removal efficiency of CSTR decreased significantly. In contrast, both the UASB and CEAR reactors maintained a high COD removal rate above 85%. Bioaugmentation can alleviate salt inhibition, enhanced microbial activity, and enriched salt-tolerant methanogens. The CEAR combined with bioaugmentation offered an effective strategy for methane recovery from high-salinity pharmaceutical wastewater.
{"title":"Assessing reactor configuration and bioaugmentation to enhance methane recovery from continuous anaerobic treatment of high-salinity pharmaceutical wastewater","authors":"Xing Cai , Chuang Liu , Sida Fu , Wansheng Shi , Zhenxing Huang , Mingxing Zhao","doi":"10.1016/j.biortech.2026.134099","DOIUrl":"10.1016/j.biortech.2026.134099","url":null,"abstract":"<div><div>This study compared the treatment of high-salinity pharmaceutical wastewater by using Continuous Stirred Tank Reactor (CSTR), Upflow Anaerobic Sludge Blanket (UASB), and two-phase Cascade Energy Anaerobic Reactor (CEAR) with bioaugmentation (<em>Bacillus altitudinis</em> K3). The CEAR significantly increased methane production through separating acidogenic and methanogenic phases, achieving a 9.70% to 23.10% higher methane content than other systems. With the increase in salinity and organic loading rate, the chemical oxygen demand (COD) removal efficiency of CSTR decreased significantly. In contrast, both the UASB and CEAR reactors maintained a high COD removal rate above 85%. Bioaugmentation can alleviate salt inhibition, enhanced microbial activity, and enriched salt-tolerant methanogens. The CEAR combined with bioaugmentation offered an effective strategy for methane recovery from high-salinity pharmaceutical wastewater.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134099"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-25DOI: 10.1016/j.biortech.2026.134092
Lianfang Zhao , Qi Zeng , Chao Li , Ming Xu
The persistence of antibiotics and nanoparticles in aquatic ecosystems poses a significant threat and complicates their removal, a challenge exacerbated by their coexistence. To address this issue, constructed wetland-microbial fuel cell (CW-MFC) systems were established not only to investigate the impact of sulfadiazine (SDZ) and copper oxide nanoparticles (CuO NPs) coexistence on system performance but, more importantly, to reveal removal mechanisms. Co-exposure suppressed chemical oxygen demand (COD) and nitrogen removal in the CW-MFC by 18.1% and 18.8%, respectively. The extracellular polymeric substances (EPS) concentration at the cathode of the CW-MFC co-exposed to SDZ and CuO NPs reached 423.10 mg g−1, enhancing Cu accumulation. Through spatial migration and separation, the CW-MFC achieved high removal efficiencies of 93.8% for SDZ and 94.9% for Cu, with spatial accumulation (51.6% of SDZ at the anode and 33.9% of Cu at the cathode). This “Simultaneous Separation-Removal” process in CW-MFC provides valuable insights into dual-contaminant treatment.
{"title":"Simultaneous removal of coexisting sulfadiazine and copper oxide nanoparticles with constructed wetland-microbial fuel cell","authors":"Lianfang Zhao , Qi Zeng , Chao Li , Ming Xu","doi":"10.1016/j.biortech.2026.134092","DOIUrl":"10.1016/j.biortech.2026.134092","url":null,"abstract":"<div><div>The persistence of antibiotics and nanoparticles in aquatic ecosystems poses a significant threat and complicates their removal, a challenge exacerbated by their coexistence. To address this issue, constructed wetland-microbial fuel cell (CW-MFC) systems were established not only to investigate the impact of sulfadiazine (SDZ) and copper oxide nanoparticles (CuO NPs) coexistence on system performance but, more importantly, to reveal removal mechanisms. Co-exposure suppressed chemical oxygen demand (COD) and nitrogen removal in the CW-MFC by 18.1% and 18.8%, respectively. The extracellular polymeric substances (EPS) concentration at the cathode of the CW-MFC co-exposed to SDZ and CuO NPs reached 423.10 mg g<sup>−1</sup>, enhancing Cu accumulation. Through spatial migration and separation, the CW-MFC achieved high removal efficiencies of 93.8% for SDZ and 94.9% for Cu, with spatial accumulation (51.6% of SDZ at the anode and 33.9% of Cu at the cathode). This “Simultaneous Separation-Removal” process in CW-MFC provides valuable insights into dual-contaminant treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134092"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-24DOI: 10.1016/j.biortech.2026.134068
Xiaomei Sun , Han Lv , Sixin Zhang , Bin Cui , Dandan Zhou
Stable NO2– supply and low-temperature inhibition represent two major bottlenecks for anaerobic ammonia oxidation (anammox) in mainstream wastewater treatment. It was reported that applied electric fields enable anaerobic ammonium-oxidizing bacteria (AnAOB) to directly oxidize NH4+ to N2. Whereas, low-temperature inhibition primarily stems from impaired electron transfer and subsequent metabolic suppression. Enhancing these processes through applied potential and conductive materials offers a strategy for this study. A single-chamber microbial electrolysis cell with 0.6 V anodic potential and 10 mg L−1 reduced graphene oxide (RGO) was developed. Results showed that the system achieved nitrogen removal rates of 7.4 ± 0.5g N m−3 d−1 and 74.2 ± 4.8 mg N m−2 d−1 at 10°C. NH4+-N and total nitrogen removal efficiencies increased by 116.6% and 147.0%, respectively. The applied potential upregulated pili/cytochrome expression, while the RGO network provided a low-resistance conductive matrix. As a result, synergic system effectively intensified electron transfer, which increased anode current density by 1.9-fold and reduced resistance by 67.7%, supporting both conventional anammox via enhanced nitritation and the electric-anammox pathway. Furthermore, it also promoted the enrichment functional genes, such as hzs and hdh (107.6%–238.1%), and enhanced cold adaptation marked by increased in extracellular proteins and polysaccharides (44.8%–18.9%). This work demonstrates coordinated electron transfer enhancement and metabolic activation through potential-RGO integration provides an innovative solution for energy-efficient nitrogen removal in cold-region wastewater treatment.
稳定的NO2供应和低温抑制是目前主流废水处理中厌氧氨氧化（anammox）的两个主要瓶颈。据报道，外加电场能使厌氧氨氧化菌（AnAOB）直接将NH4+氧化成N2。然而，低温抑制主要源于电子转移受损和随后的代谢抑制。通过应用电势和导电材料来增强这些过程为本研究提供了一种策略。研制了阳极电位为0.6 V、还原氧化石墨烯（RGO）浓度为10 mg L-1的单室微生物电解池。结果表明，在10℃条件下，该体系的氮去除率分别为7.4±0.5g N m-3 d-1和74.2±4.8 mg N m-2 d-1。NH4+-N和总氮去除效率分别提高了116.6%和147.0%。施加电位上调毛/细胞色素的表达，而RGO网络提供了一个低电阻的导电基质。结果表明，协同体系有效强化了电子传递，阳极电流密度提高了1.9倍，电阻降低了67.7%，既支持强化硝化的常规厌氧氧化，也支持电-厌氧氧化途径。此外，它还促进了hzs和hdh等功能基因的富集（107.6% ~ 238.1%），并增强了细胞外蛋白和多糖的冷适应性（44.8% ~ 18.9%）。这项工作表明，通过电位-还原氧化石墨烯的整合，协调电子转移增强和代谢激活为寒冷地区废水处理中节能脱氮提供了一种创新的解决方案。
{"title":"Synergy of potential and reduced graphene oxide enhances anaerobic nitrogen removal at 10°C: performance and mechanism","authors":"Xiaomei Sun , Han Lv , Sixin Zhang , Bin Cui , Dandan Zhou","doi":"10.1016/j.biortech.2026.134068","DOIUrl":"10.1016/j.biortech.2026.134068","url":null,"abstract":"<div><div>Stable NO<sub>2</sub><sup>–</sup> supply and low-temperature inhibition represent two major bottlenecks for anaerobic ammonia oxidation (anammox) in mainstream wastewater treatment. It was reported that applied electric fields enable anaerobic ammonium-oxidizing bacteria (AnAOB) to directly oxidize NH<sub>4</sub><sup>+</sup> to N<sub>2</sub>. Whereas, low-temperature inhibition primarily stems from impaired electron transfer and subsequent metabolic suppression. Enhancing these processes through applied potential and conductive materials offers a strategy for this study. A single-chamber microbial electrolysis cell with 0.6 V anodic potential and 10 mg L<sup>−1</sup> reduced graphene oxide (RGO) was developed. Results showed that the system achieved nitrogen removal rates of 7.4 ± 0.5g N m<sup>−3</sup> d<sup>−1</sup> and 74.2 ± 4.8 mg N m<sup>−2</sup> d<sup>−1</sup> at 10°C. NH<sub>4</sub><sup>+</sup>-N and total nitrogen removal efficiencies increased by 116.6% and 147.0%, respectively. The applied potential upregulated pili/cytochrome expression, while the RGO network provided a low-resistance conductive matrix. As a result, synergic system effectively intensified electron transfer, which increased anode current density by 1.9-fold and reduced resistance by 67.7%, supporting both conventional anammox via enhanced nitritation and the electric-anammox pathway. Furthermore, it also promoted the enrichment functional genes, such as <em>hzs</em> and <em>hdh</em> (107.6%–238.1%), and enhanced cold adaptation marked by increased in extracellular proteins and polysaccharides (44.8%–18.9%). This work demonstrates coordinated electron transfer enhancement and metabolic activation through potential-RGO integration provides an innovative solution for energy-efficient nitrogen removal in cold-region wastewater treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134068"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-23DOI: 10.1016/j.biortech.2026.134055
Yunqing Li , Xiaoying Zheng , Ruijie Hu , Jiaqing Tao , Zongshuo Han , Keyu Chen , Yifan Zhou , Yang Zhang , Wei Chen
Algal–bacterial symbiosis systems (ABS) are promising for sustainable wastewater treatment, yet their nitrogen removal performance is often compromised under low carbon-to-nitrogen (C/N) ratios commonly encountered in practical applications. In this study, a low dissolved oxygen aeration strategy was developed to construct a functional “microalgae–bacteria” network centered on nitrogen transformation. Three ABS were operated under low, medium, and high aeration intensities (10, 100, and 400 mL·min−1·L−1, designated as l-ABS, M−ABS, and H-ABS, respectively). The l-ABS achieved significantly higher total inorganic nitrogen removal than M−ABS and H-ABS, with improvements of 12.1%–13.6% (p < 0.05). Low‑intensity aeration alleviated growth constraints on Chlorella sorokiniana, promoted stable and synergistic algal–bacterial interactions, and enriched functional genes associated with nitrogen transport, electron transfer, and energy supply. Overall, this study provides a feasible and energy-efficient strategy for treating low C/N wastewater, reducing reliance on external carbon sources and intensive aeration while improving system robustness.
{"title":"Low‑intensity aeration enhances algal–bacterial synergy to improve nitrogen removal from wastewater with low carbon-to-nitrogen ratio","authors":"Yunqing Li , Xiaoying Zheng , Ruijie Hu , Jiaqing Tao , Zongshuo Han , Keyu Chen , Yifan Zhou , Yang Zhang , Wei Chen","doi":"10.1016/j.biortech.2026.134055","DOIUrl":"10.1016/j.biortech.2026.134055","url":null,"abstract":"<div><div>Algal–bacterial symbiosis systems (ABS) are promising for sustainable wastewater treatment, yet their nitrogen removal performance is often compromised under low carbon-to-nitrogen (C/N) ratios commonly encountered in practical applications. In this study, a low dissolved oxygen aeration strategy was developed to construct a functional “microalgae–bacteria” network centered on nitrogen transformation. Three ABS were operated under low, medium, and high aeration intensities (10, 100, and 400 mL·min<sup>−1</sup>·L<sup>−1</sup>, designated as <span>l</span>-ABS, M−ABS, and H-ABS, respectively). The <span>l</span>-ABS achieved significantly higher total inorganic nitrogen removal than M−ABS and H-ABS, with improvements of 12.1%–13.6% (<em>p</em> < 0.05). Low‑intensity aeration alleviated growth constraints on <em>Chlorella sorokiniana</em>, promoted stable and synergistic algal–bacterial interactions, and enriched functional genes associated with nitrogen transport, electron transfer, and energy supply. Overall, this study provides a feasible and energy-efficient strategy for treating low C/N wastewater, reducing reliance on external carbon sources and intensive aeration while improving system robustness.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134055"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-19DOI: 10.1016/j.biortech.2026.134045
Yanyan Fan , Zilong Wen , Xiaolei Chen , Gang Luo , Haisong Li
Enhancing methane production (MP) in anaerobic digestion (AD) systems largely relies on improving electron transfer between bacteria and methanogens, yet conductive materials’ acceleration effects and stability pose challenges for practical use. This study constructed continuous-flow reactors to evaluate conductive material sustainability by analyzing reactor performance and sludge characteristics under different organic loading rates (OLR), with stable mechanisms elucidated via enzyme activity, microbial community, and functional gene variation. Results revealed that the SH-mediated reactor (RSH) achieved the highest COD removal (97.0% ± 1.8%) and methane production (6.7 ± 0.2 L/d) at a high OLR of 48.7 ± 1.2 kg/(m3·d) by enriching Desulfomicrobium (19.5%) and Methanothrix (54.4%), promoting acetoclastic methanogenesis (AM) via conductive-pili gene expression. However, under ultra-high OLR, RSH became unstable due to sludge washout caused by excessive extracellular polymeric substance (EPS) secretion (184.3 ± 22.1 mg/L), which further inhibited MP activity of remaining microbes. In contrast, the PAC-mediated reactor (RPAC) maintained stability under ultra-high OLR by leveraging PAC’s inherent conductive properties and upregulating cytochrome-C and flavin-protein genes, facilitating direct interspecies electron transfer (DIET) between Clostridium (64.9%) and hydrogenotrophic methanogenesis (HM) archaea (60.5%). Both SH and PAC enhanced the performance of AD reactors; nonetheless, RSH exhibited limited OLR stress resilience due to its enhanced AD pathway having excessive metabolic activity, whereas RPAC demonstrated robust performance through the reinforced syntrophic propionate oxidation (SPO)-HM pathway. This study highlighted the balance between the strengthening effect of conductive materials and sustainability in AD optimization, which advanced understanding of conductive material applicability, offering practical insights for sustainable anaerobic digestion technologies.
{"title":"A new perspective on evaluating the critical roles of sludge hydrochar (SH) and powdered activated carbon (PAC) in anaerobic granular sludge (AnGS) reactor: Focusing on operational stability, sludge characteristics and strengthening mechanism","authors":"Yanyan Fan , Zilong Wen , Xiaolei Chen , Gang Luo , Haisong Li","doi":"10.1016/j.biortech.2026.134045","DOIUrl":"10.1016/j.biortech.2026.134045","url":null,"abstract":"<div><div>Enhancing methane production (MP) in anaerobic digestion (AD) systems largely relies on improving electron transfer between bacteria and methanogens, yet conductive materials’ acceleration effects and stability pose challenges for practical use. This study constructed continuous-flow reactors to evaluate conductive material sustainability by analyzing reactor performance and sludge characteristics under different organic loading rates (OLR), with stable mechanisms elucidated via enzyme activity, microbial community, and functional gene variation. Results revealed that the SH-mediated reactor (R<sub>SH</sub>) achieved the highest COD removal (97.0% ± 1.8%) and methane production (6.7 ± 0.2 L/d) at a high OLR of 48.7 ± 1.2 kg/(m<sup>3</sup>·d) by enriching <em>Desulfomicrobium</em> (19.5%) and <em>Methanothrix</em> (54.4%), promoting acetoclastic methanogenesis (AM) via conductive-pili gene expression. However, under ultra-high OLR, R<sub>SH</sub> became unstable due to sludge washout caused by excessive extracellular polymeric substance (EPS) secretion (184.3 ± 22.1 mg/L), which further inhibited MP activity of remaining microbes. In contrast, the PAC-mediated reactor (R<sub>PAC</sub>) maintained stability under ultra-high OLR by leveraging PAC’s inherent conductive properties and upregulating cytochrome-C and flavin-protein genes, facilitating direct interspecies electron transfer (DIET) between <em>Clostridium</em> (64.9%) and hydrogenotrophic methanogenesis (HM) archaea (60.5%). Both SH and PAC enhanced the performance of AD reactors; nonetheless, R<sub>SH</sub> exhibited limited OLR stress resilience due to its enhanced AD pathway having excessive metabolic activity, whereas R<sub>PAC</sub> demonstrated robust performance through the reinforced syntrophic propionate oxidation (SPO)-HM pathway. This study highlighted the balance between the strengthening effect of conductive materials and sustainability in AD optimization, which advanced understanding of conductive material applicability, offering practical insights for sustainable anaerobic digestion technologies.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134045"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-25DOI: 10.1016/j.biortech.2026.134090
Kun Wang , Lingling Tong , Yongjun Zhao , Junhang Zhang , Yuhang Yan , Haiwei Ji , Jinjin Sheng , Chunzhi Zhao , Haotian Wang
This study evaluated four microalgae-based technologies for nutrient (total nitrogen, TN; total phosphorus, TP; chemical oxygen demand, COD) and six antibiotic removal from swine wastewater across four breeding periods. Using Chlorella pyrenoidosa (C. pyrenoidosa), Bacillus cereus (B. cereus), and Rhizopus oryzae (R. oryzae), we established monoculture, binary co-cultures, and tripartite co-culture (Treatment 4). Treatment 4 outperformed the other treatments in the late fattening stage and non-pregnant sow stage, achieving TN removal of 89.67 ± 5.45%, TP removal of 87.58 ± 6.64%, COD removal of 92.58 ± 4.71%, and antibiotic removal of 88.54–96.35% (P < 0.05). Adding 5-deoxystrigol (5-DS) at 10–6 M maximized the efficiency, increasing the TN, TP, COD, and Oxytetracycline (OTC) removal efficiencies by 3.81–4.67% compared to those of the control (P < 0.05). This system provides a standardized solution for intensive treatment of swine wastewater.
{"title":"Combined use of microalgae-bacteria-fungi symbionts with 5-deoxystrigol to increase the removal of nutrients and antibiotics from swine wastewater during different breeding periods","authors":"Kun Wang , Lingling Tong , Yongjun Zhao , Junhang Zhang , Yuhang Yan , Haiwei Ji , Jinjin Sheng , Chunzhi Zhao , Haotian Wang","doi":"10.1016/j.biortech.2026.134090","DOIUrl":"10.1016/j.biortech.2026.134090","url":null,"abstract":"<div><div>This study evaluated four microalgae-based technologies for nutrient (total nitrogen, TN; total phosphorus, TP; chemical oxygen demand, COD) and six antibiotic removal from swine wastewater across four breeding periods. Using <em>Chlorella pyrenoidosa</em> (<em>C. pyrenoidosa</em>), <em>Bacillus cereus</em> (<em>B. cereus</em>), and <em>Rhizopus oryzae</em> (<em>R. oryzae</em>), we established monoculture, binary co-cultures, and tripartite co-culture (Treatment 4). Treatment 4 outperformed the other treatments in the late fattening stage and non-pregnant sow stage, achieving TN removal of 89.67 ± 5.45%, TP removal of 87.58 ± 6.64%, COD removal of 92.58 ± 4.71%, and antibiotic removal of 88.54–96.35% (<em>P</em> < 0.05). Adding 5-deoxystrigol (5-DS) at 10<sup>–6</sup> M maximized the efficiency, increasing the TN, TP, COD, and Oxytetracycline (OTC) removal efficiencies by 3.81–4.67% compared to those of the control (<em>P</em> < 0.05). This system provides a standardized solution for intensive treatment of swine wastewater.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134090"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-02-06DOI: 10.1016/j.biortech.2026.134165
Lanbin Zhang , Min Liu , Bing Yao , Wei Liu , Mingxiao Zeng , Fan Yuan , YuchenYan , Liqiang Yu , Jingying Liu , Ying Chen
The presence of ciprofloxacin (CIP) in swine wastewater inhibits anaerobic wastewater treatment (AWT). This study evaluated the performance of wood-based biochar (WDBC), sludge-based biochar (SLBC), and cow dung-based biochar (CDBC) as additives in AWT systems for treating simulated swine wastewater under CIP stress, aiming to identify more effective strategies to mitigate the inhibitory effects of CIP on AWT processes. Methane production in the control group (Control) added solely with CIP was 74% lower than that in the blank group without CIP addition. WDBC, SLBC, and CDBC increased methane production by 95%, 255%, and 386% versus Control, respectively. CDBC has a high mesopore proportion, aiding microbial colonization, while oxygen-containing functional groups mediate electron transfer. The high natural iron content (19%) may have enhanced extracellular electron transfer by increasing the surface redox activity. CDBC enriched Clostridium and Methanothrix, increased functional genes and regulated acidogenesis and methanogenesis. CDBC effectively alleviates CIP inhibition, enhancing AWT stability.
{"title":"Revealing ciprofloxacin inhibition mitigation and microbial function enhancement mechanisms in inherent iron-driven biochar amendment for swine wastewater anaerobic digestion","authors":"Lanbin Zhang , Min Liu , Bing Yao , Wei Liu , Mingxiao Zeng , Fan Yuan , YuchenYan , Liqiang Yu , Jingying Liu , Ying Chen","doi":"10.1016/j.biortech.2026.134165","DOIUrl":"10.1016/j.biortech.2026.134165","url":null,"abstract":"<div><div>The presence of ciprofloxacin (CIP) in swine wastewater inhibits anaerobic wastewater treatment (AWT). This study evaluated the performance of wood-based biochar (WDBC), sludge-based biochar (SLBC), and cow dung-based biochar (CDBC) as additives in AWT systems for treating simulated swine wastewater under CIP stress, aiming to identify more effective strategies to mitigate the inhibitory effects of CIP on AWT processes. Methane production in the control group (Control) added solely with CIP was 74% lower than that in the blank group without CIP addition. WDBC, SLBC, and CDBC increased methane production by 95%, 255%, and 386% versus Control, respectively. CDBC has a high mesopore proportion, aiding microbial colonization, while oxygen-containing functional groups mediate electron transfer. The high natural iron content (19%) may have enhanced extracellular electron transfer by increasing the surface redox activity. CDBC enriched <em>Clostridium</em> and <em>Methanothrix</em>, increased functional genes and regulated acidogenesis and methanogenesis. CDBC effectively alleviates CIP inhibition, enhancing AWT stability.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134165"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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