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Water disinfection is undoubtedly regarded as a critical step in ensuring the water safety for human consumption, and ozone is widely used as a highly effective disinfectant for the control of pathogenic microorganisms in water. Although the diminished ozone efficiencies in complex water matrices have been widely reported, the specific extent to which individual components of matrix act on the virus inactivation by ozone remains unclear, and effective methodologies to predict the comprehensive effects of various factors are needed. In this study, the decoupled impact of the intricate water matrix on the ozone inactivation of viruses was systematically investigated and assessed from a simulative perspective. The concept of "equivalent ozone depletion rate constant" (k') was introduced to quantify the influence of different species, and a kinetic model was developed based on the k' values for simulating the ozone inactivation processes in complex matrix. The mechanisms through which diverse species influenced the ozone inactivation effectiveness were identified: 1) competition effects (k' = 10 5 ∼10 7 M -1 s -1 ), including organic matters and reductive ions (SO 3 2- , NO 2 - , and I - ), which were the most influential species inhibiting the virus inactivation; 2) shielding effects (k' = 10 3 ∼10 4 M -1 s -1 ), including Ca 2+ , Mg 2+ , and kaolin; 3) insignificant effects (k' = 0∼1 M -1 s -1 ), including Cl - , SO 4 2- , NO 3 - , NH 4 + , and Br - . Prediction of ozone disinfection efficiency and evaluation of species contribution under complex aquatic matrices were successfully realized utilizing the model. The systematic understanding and methodologies developed in this research provide a reliable framework for predicting ozone inactivation efficiency under complex matrix, and a potential tool for accurate disinfectant dosage determination and interfering factors control in actual wastewater treatment processes.3 M -1 s -1 ), including CO 3 2- and HCO 3 - . Prediction of ozone disinfection efficiency and evaluation of species contribution under complex aquatic matrices were successfully realized utilizing the model. The systematic understanding and methodologies developed in this research provide a reliable framework for predicting ozone inactivation efficiency under complex matrix, and a potential tool for accurate disinfectant dosage determination and interfering factors control in actual wastewater treatment processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

For traditional Fenton processes, the quenching behavior of radical contenders (e.g., most aliphatic hydrocarbons) on hydroxyl radicals (·OH) usually hinders the removal of target refractory pollutants (aromatic/heterocyclic hydrocarbons) in chemical industrial wastewater, leading to excess energy consumption. Herein, we proposed an electrocatalytic-assisted chelation-Fenton (EACF) process, with no extra-chelator addition, to significantly enhance target refractory pollutant (pyrazole as a representative) removal under high ·OH contender (glyoxal) levels. Experiments and theoretical calculations proved that superoxide radical (·O 2 - ) and anodic direct electron transfer (DET) effectively converted the strong ·OH-quenching substance (glyoxal) to a weak radical competitor (oxalate) during the electrocatalytic oxidation process, promoting Fe 2+ chelation and therefore increasing radical utilization for pyrazole degradation (reached maximum of ∼43-fold value upon traditional Fenton), which appeared more obviously in neutral/alkaline Fenton conditions. For actual pharmaceutical tailwater treatment, the EACF achieved 2-folds higher oriented-oxidation capability and ∼78% lower operation cost per pyrazole removal than the traditional Fenton process, demonstrating promising potential for future practical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The mainstream deammonification of municipal wastewater has been recognized as one of the greatest challenges in wastewater engineering. The conventional activated sludge process has disadvantages of high energy input and sludge production. To tackle this situation, an innovative A-B process, where an anaerobic biofilm reactor (AnBR) functioned as the A stage for energy recovery, and a step-feed membrane bioreactor (MBR) functioned as the B stage for mainstream deammonification, was constructed for carbon-neutral wastewater treatment. For addressing the challenge associated with selective retention of ammonia-oxidizing bacteria (AOB) over nitrite oxidizing bacteria (NOB), a multi-parameter control-based operation strategy was developed with synergistic control of influent COD redistribution, dissolved oxygen (DO) concentration and sludge retention time (SRT) in the innovative AnBR - step-feed MBR system. Results showed that more than 85% of wastewater COD could be removed with the direct production of methane gas in the AnBR. A relatively stable partial nitritation, which is a prerequisite of anammox, was achieved with the successful suppression of NOB, leading to 98% of ammonium-N and 73% of total nitrogen removed. Anammox bacteria could well survive and enrich in the integrated system, and the contribution of anammox to the total nitrogen removal was more than 70% at optimal conditions. Reactions network involved in the nitrogen transformation in the integrated system was further constructed through the mass balance and microbial community structure analyses. Consequently, this study demonstrated a practically feasible process configuration with high operation and control flexibility towards stable mainstream deammonification of municipal wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ca/Fe-rich antibiotic fermentation residues (AFRs), a type of hazardous waste, can be regarded as recyclable biomass and metal resources. However, concurrent detoxification and reutilization of biomass and metals resources from AFRs have never been reported before. In this study, Ca/Fe-rich vancomycin fermentation residues were pyrolyzed into biochar to adsorb phosphate for the first time. The residual vancomycin and antibiotic resistance genes were completely decomposed during pyrolysis. The resultant Ca/Fe-rich biochar exhibited excellent performance at adsorbing phosphate without further modifications. The process had rapid kinetics and a maximum adsorption capacity of 102 mg P/g. Ca and Fe were the active sites, whereas different mechanisms were observed under acidic and alkaline conditions. Surprisingly, HCO 3 - concentration increased from 1 to 10 mM. Furthermore, actual wastewater could be effectively treated by the biochar. The phosphate-rich spent biochar significantly promoted seed germination (germination rate: 96.7 % vs. 80.0 % in control group, p < 0.01) and seedling growth (shoot length was increased by 57.9 %, p < 0.01) due to the slow release of bioavailable phosphate, and thus could be potentially used as a phosphorous fertilizer. Consequently, the hazardous waste was turned into phosphorous fertilizer, with the additional benefits of detoxifying AFRs, reutilizing biomass and metal resources from AFRs, controlling phosphate pollution, and recovering phosphate from wastewater.3 - concentration increased from 1 to 10 mM. Furthermore, actual wastewater could be effectively treated by the biochar. The phosphate-rich spent biochar significantly promoted seed germination (germination rate: 96.7 % vs. 80.0 % in control group, p < 0.01) and seedling growth (shoot length was increased by 57.9 %, p < 0.01) due to the slow release of bioavailable phosphate, and thus could be potentially used as a phosphorous fertilizer. Consequently, the hazardous waste was turned into phosphorous fertilizer, with the additional benefits of detoxifying AFRs, reutilizing biomass and metal resources from AFRs, controlling phosphate pollution, and recovering phosphate from wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Heterogeneous catalytic ozonation (HCO) is attractive for water decontamination and catalyst is a core element. However, it is difficult to maintain high efficiency and stability of catalysts under stern conditions. In this study, we proposed Mn-loaded C-SiO 2 -Framework (Mn-CSF) which contained stable silica core and robust carbon shell for efficient catalytic ozonation. The pseudo-first-order kinetic rate constant for oxalic acid removal of Mn-CSF catalytic ozonation was 160 % and 875 % higher than those of Mn-SiO 2 and pristine CSF, respectively. Mn-CSF was also proven effective in gasification wastewater treatment, where the COD was decreased to 46 mg·L -1 , 37 % lower than that of Mn-SiO 2 . These results indicated that the graphitization carbon layer and Mn significantly enhanced the activity of the catalyst. Furthermore, a fulvic-like component and a protein-like component were recognized through 3D-EEM in coal gasification wastewater. It was proven that Mn-CSF catalytic ozonation exhibited higher fulvic-like component and protein-like component removal compared with ozonation. Moreover, O 2 - and 1 were identified to be responsible for organic degradation in this research. Sufficient external specific surface area and porous structure were important for complex wastewater treatment. Specifically, external specific surface area could enhance the degradation of macromolecular organics while porous structures were vital for smaller molecular pollutant removal. The results highlighted that Mn-CSF was a promising HCO catalyst for advanced wastewater treatment, and this study provided evidence of relationship between structure of catalysts and HCO efficiency.2 were identified to be responsible for organic degradation in this research. Sufficient external specific surface area and porous structure were important for complex wastewater treatment. Specifically, external specific surface area could enhance the degradation of macromolecular organics while porous structures were vital for smaller molecular pollutant removal. The results highlighted that Mn-CSF was a promising HCO catalyst for advanced wastewater treatment, and this study provided evidence of relationship between structure of catalysts and HCO efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The conventional activated sludge (CAS) process as one of the greatest engineering marvels has made irreplaceable contributions towards the human development in the past one hundred years. However, the underlying principle of CAS which is primarily based on biological oxidation has been challenged by accelerating global climate change. In such a situation, a fundamental question that urgently needs to be answered is what wastewater treatment technology would be in the post era of activated sludge? Thus, this article illustrates the necessity of a technology paradigm shift from the current linear economy to circular economy with the energy and resource recovery from municipal wastewater being a major driver. It is argued that ammonium recovery should be considered towards the sustainable municipal wastewater reclamation. Meanwhile, the potential novel processes with enhanced energy and resource recovery are also discussed, which may offer useful insights into the ways to achieve the carbon-neutral municipal wastewater reclamation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

During catalytic ozonation, Al 2 O 3 -supported catalysts usually have stable structures but relatively low surface activity, while carbon-supported catalysts are opposite. To encourage their synergisms, we designed a Ni-induced C-Al 2 O 3 -framework ( Ni CAF) and reinforced it with a Cu-Co bimetal to create an efficient catalyst (CuCo/ Ni CAF) with a core-multishell structure. The partial graphitization of carbon adjacent to Ni crystals formed a strong out-shell on the catalyst surface. The rate constant for total organic carbon removal of CuCo/ Ni CAF (0.172 ± 0.018 min -1 ) was 67% and 310% higher than that of Al 2 O 3 -supported catalysts and Al 2 O 3 alone, respectively. The metals on CuCo/ Ni CAF contributed to surface-mediated reactions during catalytic ozonation, while the embedded carbon enhanced reactions within the solid-liquid boundary layer and in the bulk solution. Moreover, carbon embedment provided a 76% increase in ·OH-production efficiency and an 86% increase in organic-adsorption capacity compared to Al 2 O 3 -supported catalysts. During the long-term treatment of coal-gasification wastewater (∼5 m 3 day -1 ), the pilot-scale demonstration of CuCo/ Ni CAF-catalyzed ozonation revealed a 120% increase in ozone-utilization efficiency (ΔCOD/ΔO 3 = 2.12) compared to that of pure ozonation (0.96). These findings highlight catalysts supported on Ni CAF as a facile and efficient approach to achieve both high catalytic activity and excellent structural stability, demonstrating that they are highly viable for practical applications.

This study introduced a novel dual-anode assembled microbial desalination cell to enhance the performance of domestic wastewater treatment. Two parallel units were fabricated with two anodes and one cathode, which is separated by two ion exchange membrane stacks. A hollow fiber membrane module was inserted in the cathode to intercept suspended solids and microbes. Based on preliminary experiments where synthetic wastewater was utilized, anode hydraulic retention time of 10 h and cathode aeration rate of 0.16 m 3 /h were chosen as the operating conditions. By innovatively connecting four membrane stacks in cascades, which multiplied flow rate without adding extra circulation pumps, the desalination rate of the system was improved 214.8% compared with single membrane stack mode. When modified domestic wastewater was applied, the average removal efficiencies of chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorous reached 96.9%, 99.0%, 98.0% and 98.3%, respectively., (Copyright © 2018. Published by Elsevier B.V.)

Power generation using microbial fuel cells (MFCs) must provide stable, continuous conversion of organic matter in wastewaters into electricity. However, when relatively small diameter (0.8cm) graphite fiber brush anodes were placed close to the cathodes in MFCs, power generation was unstable during treatment of low strength domestic wastewater. One reactor produced 149mW/m 2 before power generation failed, while the other reactor produced 257mW/m 2 , with both reactors exhibiting severe power overshoot in polarization tests. Using separators or activated carbon cathodes did not result in stable operation as the reactors continued to exhibit power overshoot based on polarization tests. However, adding acetate (1g/L) to the wastewater produced stable performance during fed batch and continuous flow operation, and there was no power overshoot in polarization tests. These results highlight the importance of wastewater strength and brush anode size for producing stable and continuous power in compact MFCs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A larger (6.1 L) MFC stack made in a scalable configuration was constructed with four anode modules and three (two-sided) cathode modules, and tested at a wastewater treatment plant for performance in terms of chemical oxygen demand (COD) removal and power generation. Domestic wastewater was fed either in parallel (raw wastewater to each individual anode module) or series (sequentially through the chambers), with the flow direction either alternated every one or two days or kept fixed in a single direction over time. The largest impact on performance was the wastewater COD concentration, which greatly impacted power production, but did not affect the percentage of COD removal. With higher COD concentrations (∼500 mg L -1 ) and alternating flow conditions, power generation was primarily limited by the cathode specific area. In alternating flow operation, anode modules connected to two cathodes produced an average maximum power density of 6.0 ± 0.4 W m -3 , which was 1.9 ± 0.2 times that obtained for anodes connected to a single cathode. In fixed flow operation, a large subsequent decrease in COD influent concentration greatly reduced power production independent of reactor operation in parallel or serial flow modes. Anode modules connected to two cathodes did not consistently produce more power than the anodes connected to a single cathode, indicating power production became limited by restricted anode performance at low CODs. Cyclic voltammetry and electrochemical impedance spectroscopy data supported restricted anode performance with low COD. These results demonstrate that maintaining power production of MFC stack requires higher influent and effluent COD concentrations. However, overall performance of the MFC in terms of COD removal was not affected by operational modes., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Microbial desalination cells (MDCs) extract organic energy from wastewater for in situ desalination of saline water. However, to desalinate salt water, traditional MDCs often require an anolyte (wastewater) and a catholyte (other synthetic water) to produce electricity. Correspondingly, the traditional MDCs also produced anode effluent and cathode effluent, and may produce a concentrate solution, resulting in a low production of diluate. In this study, nitrogen-doped carbon nanotube membranes and Pt carbon cloths were utilized as filtration material and cathode to fabricate a modularized filtration air cathode MDC (F-MDC). With real wastewater flowing from anode to cathode, and finally to the middle membrane stack, the diluate volume production reached 82.4%, with the removal efficiency of salinity and chemical oxygen demand (COD) reached 93.6% and 97.3% respectively. The final diluate conductivity was 68 ± 12 μS/cm, and the turbidity was 0.41 NTU, which were sufficient for boiler supplementary or industrial cooling. The concentrate production was only 17.6%, and almost all the phosphorus and salt, and most of the nitrogen were recovered, potentially allowing the recovery of nutrients and other chemicals. These results show the potential utility of the modularized F-MDC in the application of municipal wastewater advanced treatment and self-driven desalination.

A novel stacked microbial fuel cell (MFC) which had a total volume of 72 L with granular activated carbon (GAC) packed bed electrodes was constructed and verified to present remarkable power generation and COD removal performance due to its advantageous design of stack and electrode configuration. During the fed-batch operation period, a power density of 50.9 ± 1.7 W/m(3) and a COD removal efficiency of 97% were achieved within 48 h. Because of the differences among MFC modules in the stack, reversal current occurred in parallel circuit connection with high external resistances (>100 Ω). This reversal current consequently reduced the electrochemical performance of some MFC modules and led to a lower power density in parallel circuit connection than that in independent circuit connection. While increasing the influent COD concentrations from 200 to 800 mg/L at hydraulic retention time of 1.25 h in continuous operation mode, the power density of stacked MFC increased from 25.6 ± 2.5 to 42.1 ± 1.2 W/m(3) and the COD removal rates increased from 1.3 to 5.2 kg COD/(m(3) d). This study demonstrated that this novel MFC stack configuration coupling with GAC packed bed electrode could be a feasible strategy to effectively scale up MFC systems., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Conductive carbon felts (Cf) were used as biofilm carriers in bioelectrochemical reactors to enhance the electrical stimulation on treatment of phenol-containing synthetic wastewater. In batch test, phenol biodegradation was accelerated under an optimum direct current (DC), which was 2mA for Cf biofilm carriers, lower than that for non-conductive white foam carriers. The stimulation effect was consistent with Adenosine Triphosphate contents in biofilms. The long-term operation further demonstrated that a high and stable phenol removal efficiency could be achieved with applied DC of 2mA, and intermittent DC application was better than continuous one, with phenol removal efficiency of over 97%. Although the quantities of whole microbial communities kept at a high level under all conditions, special microorganisms related with genera of Zoogloea and Desulfovibrio were distinctively enriched under intermittent applied DC pattern. This study shows that the electrical stimulation is potentially effective for biofilm reactors treating phenol-containing wastewater., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Conventional wastewater purification technologies consume large amounts of energy, while the abundant chemical energy and nutrient resources contained in sewage are wasted in such treatment processes. A microbial nutrient recovery cell (MNRC) has been developed to take advantage of the energy contained in wastewater, in order to simultaneously purify wastewater and recover nutrient ions. When wastewater was circulated between the anode and cathode chambers of the MNRC, the organics (COD) were removed by bacteria while ammonium and phosphate (NH4(+)-N and PO4(3-)-P) were recovered by the electrical field that was produced using in situ energy in the wastewater without additional energy input. The removal efficiencies from wastewater were >82% for COD, >96% for NH4(+)-N, and >64% for PO4(3-)-P in all the operational cycles. Simultaneously, the concentrations of NH4(+) and PO4(3-) in the recovery chamber increased to more than 1.5 and 2.2 times, respectively, compared with the initial concentrations in wastewater. The MNRC provides proof-of-concept as a sustainable, self-driven approach to efficient wastewater purification and nutrient recovery in a comprehensive bioelectrochemical system.

A homogeneous carbon membrane with multi-functions of microfiltration, electron conduction, and oxygen reduction catalysis was fabricated without using noble metals. The produced carbon membrane has a pore size of 553nm, a resistance of 6.0±0.4Ωcm(2)/cm, and a specific surface area of 32.2m(2)/g. After it was assembled in microbial fuel cell (MFC) as filtration air cathode, a power density of 581.5mW/m(2) and a current density of 1671.4mA/m(2) were achieved, comparable with previous Pt air cathode MFCs. The filtration MFC was continuously operated for 20days and excellent wastewater treatment performance was also achieved with removal efficiencies of TOC (93.6%), NH4(+)-N (97.2%), and total nitrogen (91.6%). In addition, the carbon membrane was much cheaper than traditional microfiltration membrane, suggesting a promising multi-functional material in wastewater treatment field., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs), substrate removal rates were compared in MFCs fed a single, readily biodegradable compound (acetate) or domestic wastewater (WW). Removal rates based on initial test conditions fit first-order kinetics, but rate constants varied with circuit resistance. With filtered WW (100Ω), the rate constant was 0.18h(-)(1), which was higher than acetate or filtered WW with an open circuit (0.10h(-)(1)), but CEs were much lower (15-24%) than acetate. With raw WW (100Ω), COD removal proceeded in two stages: a fast removal stage with high current production, followed by a slower removal with little current. While using MFCs increased COD removal rate due to current generation, secondary processes will be needed to reduce COD to levels suitable for discharge., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A new method for the degradation of bisphenol A (BPA) in aqueous solution was developed. The oxidative degradation characteristics of BPA in a heterogeneous Fenton reaction catalyzed by Fe3O4/graphite oxide (GO) were studied. Transmission electron microscopic images showed that the Fe3O4 nanoparticles were evenly distributed and were ∼6 nm in diameter. Experimental results suggested that BPA conversion was affected by several factors, such as the loading amount of Fe3O4/GO, pH, and initial H2O2 concentration. In the system with 1.0 g L(-1) of Fe3O4/GO and 20 mmol L(-1) of H2O2, almost 90% of BPA (20 mg L(-1)) was degraded within 6 h at pH 6.0. Based on the degradation products identified by GC-MS, the degradation pathways of BPA were proposed. In addition, the reused catalyst Fe3O4/GO still retained its catalytic activity after three cycles, indicating that Fe3O4/GO had good stability and reusability. These results demonstrated that the heterogeneous Fenton reaction catalyzed by Fe3O4/GO is a promising advanced oxidation technology for the treatment of wastewater containing BPA.