Pub Date : 2026-01-23DOI: 10.1016/j.jwpe.2026.109546
Alex Kwong Jun Kiu , Ngie Hing Wong , Hong Kiat Huang , Yali Li , Fuping Li , Diah Agustina Puspitasari , Yong Wang , Jaka Sunarso
Septic tanks require periodic desludging and further treatment at the Septic Sludge Treatment Plant (SSTP). However, the relationship between desludging frequency (DF), which is influenced by the sludge accumulation rate (SAR) in the sludge accumulation rate (SAR) inside different types of septic tanks, and the sludge generation rate (SGR) at the SSTP remains unclear. This work presents a systematic analytical approach for predicting and validating DF by simultaneously investigating the SAR and SGR from septic tanks and the SSTP, respectively. Seventy-eight (78) septic tanks, i.e., fiberglass (FG, 10), plastic (PL, 44), and reinforced concrete (RC, 24), were evaluated for their SAR based on serving population equivalent (PE) and sludge depth profiles over the years. No significant difference in SAR was found across these tanks, with an average SAR of 0.043 m3 PE-1 yr-1. To verify this, the SGR was found to range from 1.251 to 1.933 metric tons d-1 for the coarse (cs), fine (fs), and rotary drum screenings (rds) at the SSTP, resulting in a similar average SAR (0.044 m3 PE-1 yr-1). Consequently, a standardized DF of every three years is recommended for 6-PE septic tanks. This work provides insight into SAR (septic tanks) and SGR (SSTP), offering a more realistic estimate of DF to enhance their design and operational guidelines.
{"title":"Desludging frequency of septic tanks based on assessment of sludge accumulation and generation rates in septic tanks and treatment plants","authors":"Alex Kwong Jun Kiu , Ngie Hing Wong , Hong Kiat Huang , Yali Li , Fuping Li , Diah Agustina Puspitasari , Yong Wang , Jaka Sunarso","doi":"10.1016/j.jwpe.2026.109546","DOIUrl":"10.1016/j.jwpe.2026.109546","url":null,"abstract":"<div><div>Septic tanks require periodic desludging and further treatment at the Septic Sludge Treatment Plant (SSTP). However, the relationship between desludging frequency (DF), which is influenced by the sludge accumulation rate (SAR) in the sludge accumulation rate (SAR) inside different types of septic tanks, and the sludge generation rate (SGR) at the SSTP remains unclear. This work presents a systematic analytical approach for predicting and validating DF by simultaneously investigating the SAR and SGR from septic tanks and the SSTP, respectively. Seventy-eight (78) septic tanks, i.e., fiberglass (FG, 10), plastic (PL, 44), and reinforced concrete (RC, 24), were evaluated for their SAR based on serving population equivalent (PE) and sludge depth profiles over the years. No significant difference in SAR was found across these tanks, with an average SAR of 0.043 m<sup>3</sup> PE<sup>-1</sup> yr<sup>-1</sup>. To verify this, the SGR was found to range from 1.251 to 1.933 metric tons d<sup>-1</sup> for the coarse (<em>cs</em>), fine (<em>fs</em>), and rotary drum screenings (<em>rds</em>) at the SSTP, resulting in a similar average SAR (0.044 m<sup>3</sup> PE<sup>-1</sup> yr<sup>-1</sup>). Consequently, a standardized DF of every three years is recommended for 6-PE septic tanks. This work provides insight into SAR (septic tanks) and SGR (SSTP), offering a more realistic estimate of DF to enhance their design and operational guidelines.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"83 ","pages":"Article 109546"},"PeriodicalIF":6.7,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.jwpe.2026.109565
Izzati Sabri , Siti Suhailah Sharuddin , Mohd Zulkhairi Mohd Yusoff , Nor Azlan Nor Muhammad , Li Sim Ho , Toshinari Maeda , Norhayati Ramli
Phenol-degrading bacteria offer a green biotechnological route for phenol detoxification and bioplastic production through polyhydroxybutyrate (PHB) biosynthesis. However, the microbial mechanisms that link phenol degradation to PHB accumulation in palm oil mill effluent (POME) microbiomes remain poorly understood. This study provides an integrative understanding of microbial composition, active functional genes, metabolic pathways, and biochemical validation that collectively underpin phenol-to-PHB conversion. Microbial communities from POME biotreatment ponds were first analyzed using 16S rRNA amplicon sequencing, followed by metatranscriptomics profiling of the most promising community. Phenol degradation and PHB accumulation were validated in batch cultivations. Metatranscriptomics analysis of the POME microbiome from aerobic pond revealed that phenol degradation was primarily associated with the complete catechol degradation I (meta-cleavage) pathway. Concurrent expressions of catechol ortho-cleavage and protocatechuate degradation pathways, enriched in distinct taxa, suggest partial functional specialization within the community. Notably, Cupriavidus, Pseudomonas, Bacillus, and Vibrio exhibited transcriptional potential to couple phenol degradation with PHB synthesis. This community completely degraded 0.3 g/L phenol within 24 h, producing 0.06 ± 0.012 g/L PHB. Transmission electron microscopy (TEM), Fourier-transform infrared (FTIR), and 1H Nuclear Magnetic Resonance (NMR) analyses confirmed the identity of the extracted polymer as PHB. The POME microbiome shows promise for integrated phenol remediation and bioplastic production, highlighting the broader value of leveraging waste-derived microbiomes for a circular bioeconomy.
{"title":"Integrative multi-omics and biochemical validation reveal phenol-to-polyhydroxybutyrate conversion in a palm oil mill effluent microbiome","authors":"Izzati Sabri , Siti Suhailah Sharuddin , Mohd Zulkhairi Mohd Yusoff , Nor Azlan Nor Muhammad , Li Sim Ho , Toshinari Maeda , Norhayati Ramli","doi":"10.1016/j.jwpe.2026.109565","DOIUrl":"10.1016/j.jwpe.2026.109565","url":null,"abstract":"<div><div>Phenol-degrading bacteria offer a green biotechnological route for phenol detoxification and bioplastic production through polyhydroxybutyrate (PHB) biosynthesis. However, the microbial mechanisms that link phenol degradation to PHB accumulation in palm oil mill effluent (POME) microbiomes remain poorly understood. This study provides an integrative understanding of microbial composition, active functional genes, metabolic pathways, and biochemical validation that collectively underpin phenol-to-PHB conversion. Microbial communities from POME biotreatment ponds were first analyzed using 16S rRNA amplicon sequencing, followed by metatranscriptomics profiling of the most promising community. Phenol degradation and PHB accumulation were validated in batch cultivations. Metatranscriptomics analysis of the POME microbiome from aerobic pond revealed that phenol degradation was primarily associated with the complete catechol degradation I (<em>meta</em>-cleavage) pathway. Concurrent expressions of catechol <em>ortho</em>-cleavage and protocatechuate degradation pathways, enriched in distinct taxa, suggest partial functional specialization within the community. Notably, <em>Cupriavidus</em>, <em>Pseudomonas</em>, <em>Bacillus</em>, and <em>Vibrio</em> exhibited transcriptional potential to couple phenol degradation with PHB synthesis<em>.</em> This community completely degraded 0.3 g/L phenol within 24 h, producing 0.06 ± 0.012 g/L PHB. Transmission electron microscopy (TEM), Fourier-transform infrared (FTIR), and <sup>1</sup>H Nuclear Magnetic Resonance (NMR) analyses confirmed the identity of the extracted polymer as PHB. The POME microbiome shows promise for integrated phenol remediation and bioplastic production, highlighting the broader value of leveraging waste-derived microbiomes for a circular bioeconomy.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"83 ","pages":"Article 109565"},"PeriodicalIF":6.7,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109553
Arindam Sinharoy, Chong Min Chung
This study on ammonia nitrogen removal using a four-stage bioreactor system (A2/O2) highlights the strong potential of membrane-aerated biofilm reactor (MABR) technology for treating wastewater with high ammonia concentrations. The A2/O2 system with MABR achieved near-complete ammonia removal (>90%) at both moderate (160 mg/L) and high (650 mg/L) influent concentrations, significantly outperforming the control reactor without MABR (73.5% at 160 mg/L; <73.1% at 650 mg/L). This superior efficiency is attributed to the A2/O2 configuration's alternating redox zones, enhanced by MABR's counter-diffusional aeration for stable biofilms with aerobic-anoxic stratification and MBR's ultrafiltration for clarifier-free operation. These conditions facilitated simultaneous nitrification-denitrification (SND) and heterotrophic nitrification–aerobic denitrification (HN-AD), yielding 25–30% higher NH4+-N removal than Bardenpho-type controls while minimizing footprint. Additionally, both reactors demonstrated high removal of total organic carbon (97.2–100%) and total phosphorus (>82%), underscoring the MABR's capability for comprehensive pollutant removal. Microbial community analysis revealed a diverse population dominated by Proteobacteria (41.7–62.2%) and key nitrogen-cycling species such as Paracoccus denitrificans and Nitrospira japonica, which contributed to effective nitrogen removal under varying conditions. Overall, these results position MABR-based A2/O2 systems as viable upgrades for wastewater treatment plants addressing complex effluents.
{"title":"An innovative MABR-MBR integrated sequential anoxic-oxic biological (A2/O2) system for treating high-ammoniacal nitrogen containing wastewater","authors":"Arindam Sinharoy, Chong Min Chung","doi":"10.1016/j.jwpe.2026.109553","DOIUrl":"10.1016/j.jwpe.2026.109553","url":null,"abstract":"<div><div>This study on ammonia nitrogen removal using a four-stage bioreactor system (A<sup>2</sup>/O<sup>2</sup>) highlights the strong potential of membrane-aerated biofilm reactor (MABR) technology for treating wastewater with high ammonia concentrations. The A<sup>2</sup>/O<sup>2</sup> system with MABR achieved near-complete ammonia removal (>90%) at both moderate (160 mg/L) and high (650 mg/L) influent concentrations, significantly outperforming the control reactor without MABR (73.5% at 160 mg/L; <73.1% at 650 mg/L). This superior efficiency is attributed to the A<sup>2</sup>/O<sup>2</sup> configuration's alternating redox zones, enhanced by MABR's counter-diffusional aeration for stable biofilms with aerobic-anoxic stratification and MBR's ultrafiltration for clarifier-free operation. These conditions facilitated simultaneous nitrification-denitrification (SND) and heterotrophic nitrification–aerobic denitrification (HN-AD), yielding 25–30% higher NH<sub>4</sub><sup>+</sup>-N removal than Bardenpho-type controls while minimizing footprint. Additionally, both reactors demonstrated high removal of total organic carbon (97.2–100%) and total phosphorus (>82%), underscoring the MABR's capability for comprehensive pollutant removal. Microbial community analysis revealed a diverse population dominated by Proteobacteria (41.7–62.2%) and key nitrogen-cycling species such as <em>Paracoccus denitrificans</em> and <em>Nitrospira japonica</em>, which contributed to effective nitrogen removal under varying conditions. Overall, these results position MABR-based A<sup>2</sup>/O<sup>2</sup> systems as viable upgrades for wastewater treatment plants addressing complex effluents.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109553"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109535
Doaa F. Baamer , Elsayed T. Helmy , H.G. Mohamed Bakr , Amr.M. Elbasiony , Mohamed Mokhtar M. Mostafa
The creation of multifunctional catalysts for the elimination of dye pollutants and antibacterial applications is crucial within the context of global sustainability and clean water programs. A visible-light-active photocatalyst, C-doped TiO₂ (CT), and its magnetically separable nanocomposite with copper‑lead ferrite (CPF/CT) were successfully synthesized using enhanced sol-gel and co-precipitation methods. The materials were examined using various procedures. Carbon doping and composite formation with CPF significantly enhanced visible-light absorption, reducing the bandgap energy to 2.8 eV for CT and 1.24 eV for CPF/CT nanocomposite. The CPF/CT nanocomposite demonstrated remarkable photocatalytic effectiveness, achieving complete degradation of Reactive Blue 19 (RB19) under visible light, surpassing CT nanocomposite. The levels of contaminants, duration of irradiation, and quantity of catalyst all influenced performance. A notable advantage for large-scale applications is the exceptional reusability of both CT and CPF/CT nanocomposites, which maintained high efficiencies of around 87% and 97%, respectively, across five consecutive cycles. Scavenger experiments indicated that hydroxyl radicals (OH•) and electrons (e−) are the primary active species in the breakdown process. Moreover, both CT and CPF/CT nanocomposites shown significant antibacterial efficacy against several evaluated gram-positive and gram-negative microorganisms. This study demonstrates that both CT and CPF/CT nanocomposites are extremely effective and recyclable photocatalysts for wastewater treatment and exhibit considerable potential for antibacterial applications.
{"title":"Photocatalytic degradation of reactive blue 19 and antibacterial efficacy utilizing a magnetically separable C-doped TiO₂/copper-lead ferrite nanocomposite","authors":"Doaa F. Baamer , Elsayed T. Helmy , H.G. Mohamed Bakr , Amr.M. Elbasiony , Mohamed Mokhtar M. Mostafa","doi":"10.1016/j.jwpe.2026.109535","DOIUrl":"10.1016/j.jwpe.2026.109535","url":null,"abstract":"<div><div>The creation of multifunctional catalysts for the elimination of dye pollutants and antibacterial applications is crucial within the context of global sustainability and clean water programs. A visible-light-active photocatalyst, C-doped TiO₂ (CT), and its magnetically separable nanocomposite with copper‑lead ferrite (CPF/CT) were successfully synthesized using enhanced sol-gel and co-precipitation methods. The materials were examined using various procedures. Carbon doping and composite formation with CPF significantly enhanced visible-light absorption, reducing the bandgap energy to 2.8 eV for CT and 1.24 eV for CPF/CT nanocomposite. The CPF/CT nanocomposite demonstrated remarkable photocatalytic effectiveness, achieving complete degradation of Reactive Blue 19 (RB19) under visible light, surpassing CT nanocomposite. The levels of contaminants, duration of irradiation, and quantity of catalyst all influenced performance. A notable advantage for large-scale applications is the exceptional reusability of both CT and CPF/CT nanocomposites, which maintained high efficiencies of around 87% and 97%, respectively, across five consecutive cycles. Scavenger experiments indicated that hydroxyl radicals (OH<sup>•</sup>) and electrons (e<sup>−</sup>) are the primary active species in the breakdown process. Moreover, both CT and CPF/CT nanocomposites shown significant antibacterial efficacy against several evaluated gram-positive and gram-negative microorganisms. This study demonstrates that both CT and CPF/CT nanocomposites are extremely effective and recyclable photocatalysts for wastewater treatment and exhibit considerable potential for antibacterial applications.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109535"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109511
Zhi-ru Tao , Shu-xian Hou , Yi-mei Wang , Xue-chao Shi , Xin-xin Liu , Jun Ge , Yu-han Ji , Ya-qi Cheng , Zi-yi Leng , Xin-yv Cao , Rong-rong Li , Jin-nan Xuan , Jun Wang
Wastewater from biological research often contains abundant pathogenic bacteria, posing serious environmental and public health risks if discharged without treatment. Current microbial control primarily relies on antibiotics, however, their widespread use has promoted bacterial resistance, greatly reducing treatment efficacy. Furthermore, antibiotic-based methods raise concerns over residual antibiotics in water and high operational costs. To address these limitations, this study developed Na0.55MnO2·1.5H2O nanocomposites (Na-Mn-O NC), synthesized from low-cost raw materials, which significantly reduced production costs. These nanocomposites exhibit excellent biocompatibility and potent photothermal antibacterial activity. Under near-infrared (NIR) light irradiation, the temperature of the solution increases significantly with the increase in power density. When the power density reaches 1.3 W/cm2, the temperature rises to 70.4 °C. Experimental results show that the Na-Mn-O NC exhibits a pronounced heating effect after 10 min of NIR light exposure and completely inhibits bacterial growth. The photothermal conversion efficiency of the material is calculated to be 36%. Photothermal therapy (PTT) displays outstanding efficacy. Mechanistic investigations indicated that the nanocomposites induce bacterial mortality and biofilm degradation through multiple pathways, including structural damage to the cell envelope, stimulation of reactive oxygen species (ROS) production, and disruption of intracellular redox homeostasis. In simulated pathogen-laden wastewater treatment experiments, Na-Mn-O NC demonstrated outstanding and stable antibacterial performance, achieving complete inhibition of bacterial growth even after 20 cycles of reuse. It can be observed that the manganese ion content in water increased slightly after multiple cycles but remained below the 80 μg/L health guideline value set by the WHO. Furthermore, the nanocomposites can be easily recovered, mitigating potential environmental risks. This work provides a novel and sustainable strategy for disinfecting biologically contaminated wastewater, leveraging a recyclable, H2O2-independent (No additional H2O2 is required), and dual-modal antibacterial nanoplatform to combat pathogenic bacteria and impede antimicrobial resistance.
{"title":"Recyclable Na-Mn-O nanocomposite for dual-modal photothermal/ROS antibacterial therapy against multidrug-resistant bacteria in pathogen-laden wastewater","authors":"Zhi-ru Tao , Shu-xian Hou , Yi-mei Wang , Xue-chao Shi , Xin-xin Liu , Jun Ge , Yu-han Ji , Ya-qi Cheng , Zi-yi Leng , Xin-yv Cao , Rong-rong Li , Jin-nan Xuan , Jun Wang","doi":"10.1016/j.jwpe.2026.109511","DOIUrl":"10.1016/j.jwpe.2026.109511","url":null,"abstract":"<div><div>Wastewater from biological research often contains abundant pathogenic bacteria, posing serious environmental and public health risks if discharged without treatment. Current microbial control primarily relies on antibiotics, however, their widespread use has promoted bacterial resistance, greatly reducing treatment efficacy. Furthermore, antibiotic-based methods raise concerns over residual antibiotics in water and high operational costs. To address these limitations, this study developed Na<sub>0.55</sub>MnO<sub>2</sub>·1.5H<sub>2</sub>O nanocomposites (Na-Mn-O NC), synthesized from low-cost raw materials, which significantly reduced production costs. These nanocomposites exhibit excellent biocompatibility and potent photothermal antibacterial activity. Under near-infrared (NIR) light irradiation, the temperature of the solution increases significantly with the increase in power density. When the power density reaches 1.3 W/cm<sup>2</sup>, the temperature rises to 70.4 °C. Experimental results show that the Na-Mn-O NC exhibits a pronounced heating effect after 10 min of NIR light exposure and completely inhibits bacterial growth. The photothermal conversion efficiency of the material is calculated to be 36%. Photothermal therapy (PTT) displays outstanding efficacy. Mechanistic investigations indicated that the nanocomposites induce bacterial mortality and biofilm degradation through multiple pathways, including structural damage to the cell envelope, stimulation of reactive oxygen species (ROS) production, and disruption of intracellular redox homeostasis. In simulated pathogen-laden wastewater treatment experiments, Na-Mn-O NC demonstrated outstanding and stable antibacterial performance, achieving complete inhibition of bacterial growth even after 20 cycles of reuse. It can be observed that the manganese ion content in water increased slightly after multiple cycles but remained below the 80 μg/L health guideline value set by the WHO. Furthermore, the nanocomposites can be easily recovered, mitigating potential environmental risks. This work provides a novel and sustainable strategy for disinfecting biologically contaminated wastewater, leveraging a recyclable, H<sub>2</sub>O<sub>2</sub>-independent (No additional H<sub>2</sub>O<sub>2</sub> is required), and dual-modal antibacterial nanoplatform to combat pathogenic bacteria and impede antimicrobial resistance.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109511"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109517
Yanchen Li , Wenyi Dong , Qi Han , Shuo Chen , Huaguang Liu , Hongjie Wang , Yongzhen Peng
A continuous flow PN/A-AOA system integrating endogenous denitrification (EnD), partial nitrification (PN), anammox (Amx) and exogenous denitrification (Dn) was run for 360 days treating low carbon to nitrogen ratio (C/N) wastewater at different temperature (15.1 °C–27.2 °C). Results showed that the PN/A-AOA system with intermittent NH2OH (2 mg/L) dosage and bypass operation strategy could achieve stable partial nitrification in oxic tank (nitrite accumulation ratio, NAR > 90%) and advanced nitrogen removal (total inorganic nitrogen removal efficiency, TINRE > 96% and effluent TIN < 3 mg/L). EnD and Amx were the dominant pathways, with contribution proportion of 59.4%–94.2% and 11.9%–28.7% to nitrogen removal, respectively, and the flexible bypass (anaerobic tank to anoxic tank) strategy enhanced Amx contribution proportion in anoxic tank. Ex situ batch tests, enzymes activity and metagenomic analysis indicated the growth of nitrite oxidizing bacteria (NOB) was successfully inhibited, while denitrifying glycogen accumulating organisms (DGAOs) and anaerobic ammonium oxidizing bacteria (AnAOB) were highly enriched despite the drop of temperature. Moreover, the synergistic effects among DGAOs, AnAOB, ammonium oxidizing bacteria (AOB) and denitrifying bacteria (DNB) was the key of PN/A-AOA system to achieve stable and advanced nitrogen removal performance during the long-term operation.
{"title":"Continuous flow partial nitrification/anammox anaerobic-oxic-anoxic (PN/A-AOA) system for advanced nitrogen removal of low carbon to nitrogen ratio wastewater at different temperature: Long-term performance and mechanism","authors":"Yanchen Li , Wenyi Dong , Qi Han , Shuo Chen , Huaguang Liu , Hongjie Wang , Yongzhen Peng","doi":"10.1016/j.jwpe.2026.109517","DOIUrl":"10.1016/j.jwpe.2026.109517","url":null,"abstract":"<div><div>A continuous flow PN/A-AOA system integrating endogenous denitrification (EnD), partial nitrification (PN), anammox (Amx) and exogenous denitrification (Dn) was run for 360 days treating low carbon to nitrogen ratio (C/N) wastewater at different temperature (15.1 °C–27.2 °C). Results showed that the PN/A-AOA system with intermittent NH<sub>2</sub>OH (2 mg/L) dosage and bypass operation strategy could achieve stable partial nitrification in oxic tank (nitrite accumulation ratio, NAR > 90%) and advanced nitrogen removal (total inorganic nitrogen removal efficiency, TINRE > 96% and effluent TIN < 3 mg/L). EnD and Amx were the dominant pathways, with contribution proportion of 59.4%–94.2% and 11.9%–28.7% to nitrogen removal, respectively, and the flexible bypass (anaerobic tank to anoxic tank) strategy enhanced Amx contribution proportion in anoxic tank. <em>Ex situ</em> batch tests, enzymes activity and metagenomic analysis indicated the growth of nitrite oxidizing bacteria (NOB) was successfully inhibited, while denitrifying glycogen accumulating organisms (DGAOs) and anaerobic ammonium oxidizing bacteria (AnAOB) were highly enriched despite the drop of temperature. Moreover, the synergistic effects among DGAOs, AnAOB, ammonium oxidizing bacteria (AOB) and denitrifying bacteria (DNB) was the key of PN/A-AOA system to achieve stable and advanced nitrogen removal performance during the long-term operation.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109517"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109498
Xiaofang Qin , Shuyue Wang , Huaqiang Zhang , Zhanyong Fu , Jingkuan Sun , Jinzhao Ma , Fei Wang , Zhanbin Huang , Zhaohua Lu , Ping Wang , Yaxuan Zhang
The extraction of humin from coal-based humic acid waste residues represents an effective strategy for the resource utilization of solid waste. However, significant differences in the properties of humin derived from different coal sources have hindered a systematic evaluation of their adsorption capacity and immobilization efficiency for heavy metals. To address this challenge, this study investigated humin samples from Shanxi (S-CHM), Heilongjiang (D-CHM), and Inner Mongolia (N-CHM). A combination of batch adsorption experiments, laboratory simulations, and plant growth trials was employed alongside comprehensive characterization techniques (SEM/EDS, BET, Zeta potential, FTIR, 13C-CPMAS-NMR, XPS, and XRD) and model fitting analyses. Results indicated that S-CHM exhibited a high specific surface area and a microporous structure (8.57 nm), providing more surface hydroxyl (≡Si-OH) adsorption sites, with its adsorption behavior dominated by chemisorption. In contrast, D-CHM and N-CHM contained higher polycyclic aromatic hydrocarbons content, lower molecular weights, and more aliphatic chains-typical characteristics of materials governed by physical adsorption. Compared with the control (CK), soils amended with S-CHM, D-CHM, and N-CHM showed reductions of 2.47%–8.12% in acid-extractable Cd fractions and 2.47%–8.10% in the biological activity coefficient. Additionally, the ecological risk index (KRSP) for heavy metals decreased by 21.01%–28.56%. These findings indicated that the coal-based humins effectively suppressed Cd release and mobility in soils, enhancing cadmium immobilization and reducing environmental risk. This study provides a systematic assessment of coal-based humins from different sources, clarifying their potential for Cd pollution remediation, offering a theoretical basis for applications in water purification and soil remediation.
{"title":"Resource utilization of multi-source coal-based humic acid residues: Enhancing the remediation potential of cadmium pollution in water-soil-plant systems","authors":"Xiaofang Qin , Shuyue Wang , Huaqiang Zhang , Zhanyong Fu , Jingkuan Sun , Jinzhao Ma , Fei Wang , Zhanbin Huang , Zhaohua Lu , Ping Wang , Yaxuan Zhang","doi":"10.1016/j.jwpe.2026.109498","DOIUrl":"10.1016/j.jwpe.2026.109498","url":null,"abstract":"<div><div>The extraction of humin from coal-based humic acid waste residues represents an effective strategy for the resource utilization of solid waste. However, significant differences in the properties of humin derived from different coal sources have hindered a systematic evaluation of their adsorption capacity and immobilization efficiency for heavy metals. To address this challenge, this study investigated humin samples from Shanxi (S-CHM), Heilongjiang (D-CHM), and Inner Mongolia (N-CHM). A combination of batch adsorption experiments, laboratory simulations, and plant growth trials was employed alongside comprehensive characterization techniques (SEM/EDS, BET, Zeta potential, FTIR, <sup>13</sup>C-CPMAS-NMR, XPS, and XRD) and model fitting analyses. Results indicated that S-CHM exhibited a high specific surface area and a microporous structure (8.57 nm), providing more surface hydroxyl (≡Si-OH) adsorption sites, with its adsorption behavior dominated by chemisorption. In contrast, D-CHM and N-CHM contained higher polycyclic aromatic hydrocarbons content, lower molecular weights, and more aliphatic chains-typical characteristics of materials governed by physical adsorption. Compared with the control (CK), soils amended with S-CHM, D-CHM, and N-CHM showed reductions of 2.47%–8.12% in acid-extractable Cd fractions and 2.47%–8.10% in the biological activity coefficient. Additionally, the ecological risk index (K<sub><em>RSP</em></sub>) for heavy metals decreased by 21.01%–28.56%. These findings indicated that the coal-based humins effectively suppressed Cd release and mobility in soils, enhancing cadmium immobilization and reducing environmental risk. This study provides a systematic assessment of coal-based humins from different sources, clarifying their potential for Cd pollution remediation, offering a theoretical basis for applications in water purification and soil remediation.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109498"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.jwpe.2026.109515
M. Bhavani Lakshmi , Alibasha Akbar , Tanmay Chatterjee , Archana V. , Quazi Arif Islam , Mihir Ghosh
ZnO nanocomposite-derived porous carbon was synthesized via an eco-friendly one-step calcination method using Opuntia ficus-indica leaves and zinc chloride (1: 1 ratio) as a sustainable carbon–zinc precursor. The resultant mesoporous ZnO@porous activated carbon (ZnO@PAC), calcined at 600 °C, exhibited a high BET surface area of 278.69 m2/g with an average pore diameter of 4.17 nm, facilitating exceptional adsorption capacities of 661.12 mg g−1, 930.01 mg g−1, and 1497.19 mg g−1 for methylene blue (MB), brilliant green (BG), and methyl violet (MV), respectively. Compared to commercially available ZnO, the synthesized ZnO@PAC composite exhibited markedly enhanced adsorption efficiency toward cationic dyes, which can be attributed to its higher surface area, improved porosity, and synergistic interaction between ZnO nanoparticles and the porous activated carbon framework. Adsorption studies conducted under alkaline conditions (pH 9) showed rapid attainment of equilibrium within 60 min for MB and BG, and 100 min for MV. The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, indicating that monolayer chemisorption is predominantly influenced by hydrogen bonding, π–π interactions, and electrostatic attraction, with the pH-dependent surface charge playing a critical role. Practical applicability was demonstrated using two different real industrial wastewater samples. In the first industrial effluent, a dye removal efficiency of 80% was achieved within 60 min, whereas treatment of a second industrial wastewater resulted in a higher removal efficiency of 94.46% in 70 min. Phytotoxicity assays using Vigna radiata (moong bean) showed that ZnO@PAC–treated MB-, BG-, and MV-contaminated waters restored root growth to 75% and shoot growth to 85%, respectively, relative to the negative control, demonstrating substantial recovery compared to the severe inhibition observed in the positive control. The adsorbent demonstrated strong stability and efficiency across five ethanol-assisted regeneration cycles, demonstrating that ZnO@PAC is a highly effective and eco-friendly option for dye removal and water reuse in irrigation and wastewater treatment.
以无花果叶片和氯化锌（1:1）为可持续碳锌前驱体，采用一步煅烧法制备了ZnO纳米复合材料多孔碳。在600℃下煅烧得到的ZnO@porous介孔活性炭（ZnO@PAC）具有278.69 m2/g的BET比表面积，平均孔径为4.17 nm，对亚甲基蓝（MB）、亮绿（BG）和甲基紫（MV）的吸附量分别为661.12 mg g - 1、930.01 mg g - 1和1497.19 mg g - 1。与市售ZnO相比，合成的ZnO@PAC复合材料对阳离子染料的吸附效率显著提高，这可归因于其更高的比表面积、更好的孔隙率以及ZnO纳米颗粒与多孔活性炭框架之间的协同作用。在碱性条件下（pH 9）进行的吸附研究表明，MB和BG在60分钟内快速达到平衡，MV在100分钟内达到平衡。吸附过程遵循Langmuir等温线和拟二级动力学，表明单层化学吸附主要受氢键、π -π相互作用和静电吸引的影响，其中ph依赖的表面电荷起关键作用。通过两种不同的实际工业废水样品验证了该方法的实用性。在第一个工业废水中，在60分钟内实现了80%的染料去除效率，而在第二个工业废水的处理中，在70分钟内实现了94.46%的更高去除效率。利用Vigna radiata（月豆）进行的植物毒性试验表明，ZnO@PAC -处理过的MB-、BG-和mv污染的水，相对于阴性对照，分别使根的生长恢复到75%，茎的生长恢复到85%，与阳性对照的严重抑制相比，显示出明显的恢复。该吸附剂在五个乙醇辅助再生循环中表现出很强的稳定性和效率，表明ZnO@PAC是一种高效环保的染料去除和灌溉和废水处理中水回用的选择。
{"title":"Wurtzite ZnO nanoflower carbon composite for cationic dye adsorption, phytotoxicity study, and industrial wastewater remediation","authors":"M. Bhavani Lakshmi , Alibasha Akbar , Tanmay Chatterjee , Archana V. , Quazi Arif Islam , Mihir Ghosh","doi":"10.1016/j.jwpe.2026.109515","DOIUrl":"10.1016/j.jwpe.2026.109515","url":null,"abstract":"<div><div>ZnO nanocomposite-derived porous carbon was synthesized via an eco-friendly one-step calcination method using <em>Opuntia ficus-indica</em> leaves and zinc chloride (1: 1 ratio) as a sustainable carbon–zinc precursor. The resultant mesoporous ZnO@porous activated carbon (ZnO@PAC), calcined at 600 °C, exhibited a high BET surface area of 278.69 m<sup>2</sup>/g with an average pore diameter of 4.17 nm, facilitating exceptional adsorption capacities of 661.12 mg g<sup>−1</sup>, 930.01 mg g<sup>−1</sup>, and 1497.19 mg g<sup>−1</sup> for methylene blue (MB), brilliant green (BG), and methyl violet (MV), respectively. Compared to commercially available ZnO, the synthesized ZnO@PAC composite exhibited markedly enhanced adsorption efficiency toward cationic dyes, which can be attributed to its higher surface area, improved porosity, and synergistic interaction between ZnO nanoparticles and the porous activated carbon framework. Adsorption studies conducted under alkaline conditions (pH 9) showed rapid attainment of equilibrium within 60 min for MB and BG, and 100 min for MV. The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics, indicating that monolayer chemisorption is predominantly influenced by hydrogen bonding, π–π interactions, and electrostatic attraction, with the pH-dependent surface charge playing a critical role. Practical applicability was demonstrated using two different real industrial wastewater samples. In the first industrial effluent, a dye removal efficiency of 80% was achieved within 60 min, whereas treatment of a second industrial wastewater resulted in a higher removal efficiency of 94.46% in 70 min. Phytotoxicity assays using <em>Vigna radiata</em> (moong bean) showed that ZnO@PAC–treated MB-, BG-, and MV-contaminated waters restored root growth to 75% and shoot growth to 85%, respectively, relative to the negative control, demonstrating substantial recovery compared to the severe inhibition observed in the positive control. The adsorbent demonstrated strong stability and efficiency across five ethanol-assisted regeneration cycles, demonstrating that ZnO@PAC is a highly effective and eco-friendly option for dye removal and water reuse in irrigation and wastewater treatment.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109515"},"PeriodicalIF":6.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vertical stability of anammox communities is critical for sustaining high-rate nitrogen removal in expanded granular sludge bed (EGSB) reactors. This study investigated microbial structures, interactions, and assembly mechanisms under reductions in hydraulic retention time (HRT) and adjustments to upflow velocity. Shortening HRT to 4 h expanded active anammox blanket toward the upper reactor, increased ccsA abundance, and reinforced electron-transfer capacity. Deterministic selection intensified, as higher volumetric loading and deeper DO penetration sharpened niche filters in lower zones, while greater substrate availability in the upper reactor favored oxygen-tolerant Candidatus Brocadia, enabling its upward expansion and dominance. Shortened HRT also fostered cohesive interaction networks with keystone taxa that stabilized core functional guilds (Planctomycetota, Proteobacteria, and Chloroflexi). In parallel, upflow velocity mainly influenced anammox granule distribution and hydrodynamic stability, with community assembly shaped by heterogeneous selection and stochasticity in the upper reactor. These findings highlight that targeted HRT control consolidates core-zone stability and extends functional activity upward, ensuring efficient nitrogen removal.
{"title":"Vertical microbial assembly mechanisms in anammox-EGSB: elucidating HRT and upflow velocity as key drivers of nitrogen conversion stratification","authors":"Xin Wang, Yijing Zhu, Antao Yao, Yihan Huang, Shuyun Wang, Jianghua Yu","doi":"10.1016/j.jwpe.2026.109533","DOIUrl":"10.1016/j.jwpe.2026.109533","url":null,"abstract":"<div><div>Vertical stability of anammox communities is critical for sustaining high-rate nitrogen removal in expanded granular sludge bed (EGSB) reactors. This study investigated microbial structures, interactions, and assembly mechanisms under reductions in hydraulic retention time (HRT) and adjustments to upflow velocity. Shortening HRT to 4 h expanded active anammox blanket toward the upper reactor, increased <em>ccsA</em> abundance, and reinforced electron-transfer capacity. Deterministic selection intensified, as higher volumetric loading and deeper DO penetration sharpened niche filters in lower zones, while greater substrate availability in the upper reactor favored oxygen-tolerant Candidatus <em>Brocadia</em>, enabling its upward expansion and dominance. Shortened HRT also fostered cohesive interaction networks with keystone taxa that stabilized core functional guilds (<em>Planctomycetota</em>, <em>Proteobacteria</em>, and <em>Chloroflexi</em>). In parallel, upflow velocity mainly influenced anammox granule distribution and hydrodynamic stability, with community assembly shaped by heterogeneous selection and stochasticity in the upper reactor. These findings highlight that targeted HRT control consolidates core-zone stability and extends functional activity upward, ensuring efficient nitrogen removal.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109533"},"PeriodicalIF":6.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-21DOI: 10.1016/j.jwpe.2026.109490
JunJie Huang , PengFei Xie , XiaoYu Wang , XueYing Zai , Jing Yu , Min Song , GuangYing Weng , Miao Yu , XianYong Ma , Dun Deng
The efficient valorization of swine wastewater is hampered by high pathogen loads and significant nitrogen (N) loss during conventional treatment. This study presents and validates an innovative three-stage process, termed the “Acidic Nitrogen Fixation and Alkaline Neutralization” (ANFAN) process, designed to transform this nitrogen-loss paradigm by converting SWW into a safe, nutrient-enriched bio-fertilizer. The process is initiated with a low-dose ozone pretreatment (20 mg·L-1, 15 min), which achieves >99% inactivation of key pathogens, including Listeria monocytogenes (99.92%) and Escherichia coli (99.18%), thereby effectively overcoming the primary biosafety hurdle. The core of the process is an acidic nitrogen fixation stage, where at a controlled pH of 3, an inoculated, earthworm-derived diazotrophic consortium fixes atmospheric N2 while suppressing N-loss pathways, resulting in a substantial net TN increase of approximately 50%. In the final stage, alkaline neutralization adjusts the bio-fertilizer to a pH of 6.5 to ensure agronomic safety and mitigate soil acidification risks. Metagenomic analysis confirmed this functional basis, revealing a significant upregulation of key genes involved in nitrogen fixation (nif) and assimilation (nas). Pot experiments using Brassica rapa var. chinensis demonstrated the significant plant-growth-promoting potential of the resulting bio-fertilizer, providing direct evidence of its agronomic viability. The ANFAN process thus establishes a mechanism-supported, cost-effective pathway for the safe and efficient nutrient recovery from livestock wastewater, thereby advancing the circular agricultural economy.
{"title":"Direct preparation of a liquid bio-fertilizer from swine wastewater using ozone and earthworm-derived nitrogen-fixing bacteria to enhance nitrogen nutrition","authors":"JunJie Huang , PengFei Xie , XiaoYu Wang , XueYing Zai , Jing Yu , Min Song , GuangYing Weng , Miao Yu , XianYong Ma , Dun Deng","doi":"10.1016/j.jwpe.2026.109490","DOIUrl":"10.1016/j.jwpe.2026.109490","url":null,"abstract":"<div><div>The efficient valorization of swine wastewater is hampered by high pathogen loads and significant nitrogen (N) loss during conventional treatment. This study presents and validates an innovative three-stage process, termed the “Acidic Nitrogen Fixation and Alkaline Neutralization” (ANFAN) process, designed to transform this nitrogen-loss paradigm by converting SWW into a safe, nutrient-enriched bio-fertilizer. The process is initiated with a low-dose ozone pretreatment (20 mg·L<sup>-1</sup>, 15 min), which achieves >99% inactivation of key pathogens, including <em>Listeria monocytogenes</em> (99.92%) and <em>Escherichia coli</em> (99.18%), thereby effectively overcoming the primary biosafety hurdle. The core of the process is an acidic nitrogen fixation stage, where at a controlled pH of 3, an inoculated, earthworm-derived diazotrophic consortium fixes atmospheric N<sub>2</sub> while suppressing N-loss pathways, resulting in a substantial net TN increase of approximately 50%. In the final stage, alkaline neutralization adjusts the bio-fertilizer to a pH of 6.5 to ensure agronomic safety and mitigate soil acidification risks. Metagenomic analysis confirmed this functional basis, revealing a significant upregulation of key genes involved in nitrogen fixation (nif) and assimilation (nas). Pot experiments using <em>Brassica rapa</em> var. chinensis demonstrated the significant plant-growth-promoting potential of the resulting bio-fertilizer, providing direct evidence of its agronomic viability. The ANFAN process thus establishes a mechanism-supported, cost-effective pathway for the safe and efficient nutrient recovery from livestock wastewater, thereby advancing the circular agricultural economy.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"82 ","pages":"Article 109490"},"PeriodicalIF":6.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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