COD Removal Rate Research Articles

The effect of microbial electrolysis cell coupled with anaerobic digestion for landfill leachate treatment

Landfill leachate contained high salinity and refractory organic compounds, poses significant challenges for treatment. The microbial electrolysis cell coupled with anaerobic digestion (MEC-AD) offers an effective solution by enhancing current transfer and improving electrochemical treatment efficacy across different salinity. The effects of landfill leachate salinity (5–40 g/L) on both MEC-AD and AD were investigated in this study. The findings revealed that at 10 g/L of NaCl concentration, the MEC-AD achieved 37 % of COD removal rate. Furthermore, even when the NaCl concentration was increased to 24 g/L and 40 g/L, MEC-AD continued to outperform AD. In MEC-AD, the complementary cyclic voltammetry (CV) demonstrated that increased salinity enhances the electrochemical activity and electron transfer capacity of the anode biofilm. Additionally, microbial community analysis revealed progressive shift in the dominant microbial phyla from Firmicutes (26 %) and Chloroflexi (22 %) to Proteobacteria (23–39 %), Chloroflexi (25–39 %), and Bacteroidota (10–21 %).

Control of organic and biological fouling of polyethersulfone membrane by blending and surface modification using natural additives

In this study, a modified polyethersulfone (PES) membrane was fabricated by blending collagen (COL) in the PES dope solution and the subsequent coating with chitosan (CHI) – polyphenon from green tea (PGT). The antifouling and antibacterial properties of all prepared membranes were evaluated. The results demonstrated that the CHI and PGT coating on COL-incorporated membrane exhibited enhanced hydrophilicity and flux recovery compared with the pristine PES membrane. The best solute rejection and control of foulant adsorption were observed with the optimized modified membrane (0.3COL@0.6CHI/0.6PGT). Also, the 0.3COL@0.6CHI/0.6PGT membrane showed a predominant inhibition zone area, suggesting the excellent antibacterial properties of the membrane. During surface water filtration, the removal rates of COD, TDS, conductivity, and turbidity were enhanced from 32.2 % to 52.5 %, from 67.2 % to 72.7 %, from 12.9 % to 24.7 %, and from 70.8 % to 92.2 %, respectively, by using the optimized modified membrane. Furthermore, the outstanding performance of membrane stability, in terms of hydrophilicity and antibacterial properties, was also confirmed by water contact angle and inhibition zone analyses. This study provided an effective and environmentally-friendly method for modification of PES membrane with enhanced antifouling and antibacterial performance.

Performance of Combined Sedimentation and Constructed Wetland System for Blackwater treatment

A constructed wetland system pilot project was constructed in 2022 in one of the houses in Al-Diwaniyah Governorate, Iraq. This system is a constructed wetland system (CWS). This system was planted with Typha domingensis. The present research deals with blackwater collected from a single house in Iraq’s Al-Diwaniyah Governorate. This house consists of three apartments. Water from these flats is drained into separate water manholes (BW and GW). Black water (BW) collected is the subject of the current study, where the black water was discharged from the manhole to the constructed wetland station in the house. This study is to investigate various treatment processes for treating blackwater for reuse. Blackwater treatment was examined first in batch tests to define optimal operating conditions, which include the settling time. The experimental method involves evaluation of the treated effluent to reach the allowable limits of water reuse according to Iraqi quality standards to reuse the water for irrigation (IQS 2012) and Egypt’s reclaimed water reuse standards (Egypt Decree 2013). The efficiency of a sedimentation operation was examined from to determine the optimum time. Further treatment by Constructed wetland was examined. Final overall removal rates for TSS, BOD5, COD, TP, and TN were 97.16%, 91%, 81%, 63%, and 69.2%, respectively. The present study that Constructed wetland could successfully efficient to removing the contamination by saving space, energy and labor less.

Pharmaceutical and personal care products (PPCPs) degradation and microbial characteristics of low-temperature operation combined with constructed wetlands

Emerging contaminants (ECs), which are present in water bodies, could cause global environmental and human health problems. These contaminants originate from various sources such as hospitals, clinics, households, and industries. Additionally, they can also indirectly enter the water supply through runoff from agriculture and leachate from landfills. ECs, specifically Pharmaceutical and personal care products (PPCPs), are causing widespread concern due to their contribution to persistent water pollution. Traditional approaches often involve expensive chemicals and energy or result in the creation of by-products. This study developed a practical and environmentally-friendly method for removing PPCPs, which involved combining and integrating various techniques. To implement this method, it was necessary to establish and used a field simulator based on the real-life scenario. Based on the data analysis, the average removal rates of COD, TP, TN, and NH4+-N were 57%, 59%, 63%, and 73%, respectively. the removal rate of PPCPs by CCWs was found to be 82.7% after comparing samples that were not treated by constructed wetlands and those that were treated. Combined constructed wetlands (CCWs) were found to effectively remove PPCPs from water. This is due to the combined action of plant absorption, absorption, and biodegradation by microorganisms living in the wetlands. Interestingly, the wetland plant reed had been shown to play an important role in removing these pollutants. Microbial degradation was the most important pathway for PPCPs removal in CCWs. Carbamazepine was selected as a typical PPCP for analysis. In addition, the microbial community structure of the composite filler was also investigated. High-throughput sequencing confirmed that the dominant bacteria had good adaptability to PPCPs. This technique not only reduced the potential environmental impact but also served as a foundation for further research on the use of constructed wetlands for the treatment of PPCPs contaminated water bodies and its large-scale implementation.

Efficient treatment of starch wastewater through metallic-starch complexes and magnetic flocculation

Starch wastewater poses significant environmental harm, necessitating the implementation of effective treatment methods. The current starch wastewater treatment methods have some drawbacks, such as limited application scenarios, complicated process and insufficient purification efficiency. This study focuses on the purification of starch wastewater through metallic-starch complexes (MSCs) and magnetic flocculation. Metal ions (Fe3+, Pb2+ and Al3+) were added to interact with starch and coagulate, forming MSCs, in which the O6 atom of the branched chain methanol most likely to interact with metal ions. Then, the magnetic particles, sintering dust (SD), was utilized to adsorb the MSCs and form magnetic flocs, facilitating their rapid settlement under an external magnetic field. The purification experiments were aimed at a high-concentration starch wastewater with COD concentration of 12,000 mg/L, and the results demonstrated the metal ions could effectively coordinate with starch and form MSCs, achieving a COD removal rate of over 90%. Meanwhile, to address the challenge of difficult settlement of MSCs, the addition of SD induced the magnetic flocculation with MSCs through Van der Waals force and electrostatic force, which effectively reduced settling time and decreased sedimentation layer thickness. The combined use of MSCs and magnetic flocculation achieved efficient purification of starch wastewater.

Purification mechanism of microbial metabolism in kitchen-oil wastewater enhanced by cationic vacancies on γ-Al2O3

The use of catalyst materials to mediate the enhancement of microbial degradation in wastewater is a new economic and energy saving breakthrough in water treatment technology. In this study, γ-Al2O3, which is commonly used as catalyst/carrier, is used as biological filler to treat kitchen-oil wastewater with low biodegradability, and the COD removal rate is about 50 %. It is found that the complexation of cationic vacancies on Al2O3 surface with extracellular polymeric substance (EPS) secreted by microorganisms in wastewater lead to the polarization of electron distribution on biofilm. The efficient degrading bacteria are enriched on reaction interface and obtain electrons to maintain electron dynamic balance by enhancing the transmembrane metabolism of pollutants. The aluminum vacancies on Al2O3 surface accelerate the microbial degradation of pollutants. The cationic vacancies in the structure of catalyst accelerate the acquisition of exogenous electrons by microorganisms without the addition of external energy, which provides a new idea for catalytic fillers to enhance wastewater degradation.

Enhanced treatment of sludge drying condensate by A/O-MBR process: Microbial activity and community structure

With the rapid increase of sludge production from sewage treatment plants, the treatment of sludge drying condensate rich in a large amount of pollutants urgently needs to be addressed. Due to the unique characteristics of sludge drying condensate (high ammonia nitrogen and COD concentration), there are almost no reports on biological treatment methods specifically targeting sludge drying condensate. In this study, A/O-MBR process was proposed for sludge drying condensate treatment and the effects of ammonia nitrogen loads, alkalinity and aeration intensity were explored. Experimental results show that under the ammonia nitrogen load of 0.35 kg NH4+-N/(m3·d) and the aeration intensity of 0.5 m3/(m2·min), the removal rate of COD and NH4+-N could reach 94% and 99.86% with the addition of alkalinity (m(NaHCO3): m(NH4+-N) = 7:1), respectively. The distribution of living and dead microbial cells in the activated sludge of three reactors also proved that the supplement of alkalinity in the influent can ensure the feasible living conditions for microorganisms. In addition to traditional nitrifying bacteria, through the supplementation of alkalinity and the reduction of aeration intensity, the system had also domesticated high abundance heterogeneous nitrification aerobic denitrification (HN-AD) and aerobic denitrification bacteria (both more than 10% of the total bacterial count). The denitrification process of sludge drying condensate was simplified and the denitrification efficiency was greatly improved. The findings of this study could provide important theoretical guidance for the biological treatment process of sludge drying condensate.

Applying sheet iron to enhance the treatment efficiency of digested effluent with continuous flow and the corresponding mechanism

Because of the unstable wastewater quantity and quality, the biological treatment efficiency of digested effluent was not as expected. A convenient and effective way was eagerly required to improve the efficiency of biological treatment. By sheet iron addition (R1), the COD and TN removal efficiencies under continuous flow condition increased by 59% and 37% respectively. The bulk pH maintained at around 7.5 which benefited most bacteria, while in the control (R0, without sheet iron addition) the pH decreased to 5.0. Both chemical and bio-removal of COD existed in R1, but the chemical removal dominated (63.71%). The enhanced COD removal efficiency came from the chemical oxidation by Fe3+ (47.43%) and Fe0 (10.86%). For the TN removal, the enhancement mainly came from the improvement of anammox activity by Fe3+ (14.87%), the bio-oxidation of ammonium with Fe3+ as electron acceptor (8.78%), and the bio-reduction of nitrate/nitrite with Fe2+ and H2 as electron donor (35.76%). By the first-order kinetic fitting analysis, the COD and TN removal rate in R1 was higher than that in R0. Thus, for a quick and high COD and TN removal from digested effluent, the addition of Fe0/Fe2+/Fe3+ was suggested, and the best form should be Fe0 (e.g., sheet iron). The addition of sheet iron reduces the cost of nitrogen removal and improves the efficiency of COD and TN removal. Comparing with the combined processes, this novel approach has potential advantages with simple operation and high efficiency. It endows the biological process much broader application in digested effluent treatment.

Research of synergistic effect of magnetic powder and biosurfactant in pollutants removal and membrane fouling alleviation

This study constructed a rhamnolipid-magnetic membrane reactor (RL-MMBR) coupled system to investigate the effects of RL and magnetic powder on membrane fouling alleviation and wastewater treatment efficiency. The optimal concentration was determined by comparing the effects of different concentrations of RL and magnetic powder as well as single and mixed injection on the operation performance. The effects of RL and magnetic powder on pollutant degradation and membrane fouling were investigated at the optimum concentration (300 mg/L RL + 120 mg/L Fe3O4). It was found that the time for TMP to reach 30 kpa in RL-MMBR was 7 days longer than that in CMBR. In the RL-MMBR, the concentration of SMP declined from 13.22 mg/L to 6.75 mg/L and the concentration of LB-EPS decreased from 14.37 mg/L to 7.95 mg/L, and their concentration in RL-MMBR was gradually lower than that in CMBR. But the concentration of TB-EPS in RL-MMBR was always greater than that of CMBR. The sludge particle size in RL-MMBR was gradually larger than that in CMBR. The overall COD removal rate of RL-MMBR (95 %-98 %) was better than that of CMBR (91 %-95 %). The synergistic effect increased the species abundance and diversity of microorganisms in the sludge mixture, but reduced the enrichment of microorganisms on the membrane, especially reduced the adhesion of high-viscosity microorganism Proteobacteria to the membrane. The RL-MMBR coupled system improved the degradation efficiency and alleviated the membrane fouling. In addition, the direct dosing of the agent increased the convenience of operation, the recycling of the magnetic powder reduced the operating cost, and the reaction had no secondary pollution. This provided new ideas and theoretical guidance for solving membrane fouling problems in MBR treatment of domestic sewage.

Simultaneous degradation efficiency of C-MFCs for three pollutants in aquaculture wastewater

<p>Chlorella microbial fuel cells may be an alternative technology for wastewater treatment. Using microalgae and activated sludge as raw materials, a C-MFCs was established, and the effects of different nitrogen and phosphorus ratios in the influent on the electrochemical performance of C-MFCs and the removal effect of NH3-N, COD and TP were investigated. The results show that when N:P=3:1 and the external resistance is 1000 Ω, the removal rates of NH3-N, COD and TP are 72.48±1.94%, 81.26±4.4% and 65.62%±2.14%, respectively, and the highest chlorophyll a content is 108.82 mg/L. The maximum voltage and maximum power 92.94 mV and 234.01 mW/m2. The microbial community structure in the anode chamber was analyzed and the results are as follows: At N:P=3:1, the dominant bacteria at the genus level in the anode chamber were Klebsiella (32.12%) and Prevotella (14.45%). The number of OTUs in the anode chamber changes under different N:P conditions. It can be concluded that N:P affects the power generation capacity of C-MFCs and the removal of NH3-N, COD and TP. Overall,when N:P=3:1, the C-MFCs had the best power production capacity and the removal of NH3-N, COD and TP. Regulation of N:P in aquaculture wastewater is an effective way to improve performance of C-MFCs.</p>

Sugarcane-bagasse-ash in enhanced mesophilic Co-digestion for biogas and nutrient recovery: A concept of developing rural circular bioeconomy

Conductive agro-industrial wastes as accelerants in the anaerobic digestion (AD) of organic waste is a good technique for developing a rural circular economy, such as producing bioenergy and biofertilizer. This study disclosed the a role of sugar cane bagasse ash (SCBA) in enhancing the bioenergy (biogas) yield and digestate fertility via anaerobic co-digestion (AcoD) of buffalo dung (BD) and vegetable residue (VR) under mesophilic conditions (37 ᴼC). Firstly, an optimal BD/VR ratio (1:3) was determined based on biogas yield by introducing five different BD/VR ratios (1:0, 3:1, 1:1, 1:3, and 0:1) into AcoD systems. Secondly, the biogas yield was increased further by adding SCBA at five different concentrations (0, 0.5, 1, 1.5, and 2 wt%). Experimental results disclosed that the 1.5 wt% of SCBA gave the highest cumulative biogas yield (153.67 mL/g VS), COD removal rate (31.18%), and fertility (5.08%). Moreover, a framework is suggested to understand the role of SCBA in the enhanced DIET mechanism. This work documents an environmentally friendly and economical technique for developing a rural circular bioeconomy via the AD of organic agro-waste.

Mn-SR as an ozone catalyst for coal to ethylene glycol organic wastewater treatment: Activity evaluation and reaction mechanism

Large amounts of soda residue waste from the production of sodium carbonate industries cause serious pollution to environment. In this study, a novel Mn-SR non-homogeneous ozone catalyst was prepared by mixed calcination method using soda residue as the main component for organics degradation of coal to ethylene glycol wastewater. Firstly, under the optimal Mn-SR preparation process (95% n-SR (msoda residue: mkaolin = 8:1), 5% MnO2, calcination temperature: 500 °C, calcination time: 4 h) and the optimal operating conditions (pH: 8, water temperature: 40 °C, catalyst dosage: 320 g/L, O3 dosage: 20 g/L) for the reaction of 60 min, the COD removal rate reaches to 77.1%, which is 63.9% higher than only ozonation COD removal efficiency under the same conditions. Kinetic study shows that water temperature is the most important factor affecting COD degradation rate in the reaction system. Through the adsorption performance, ozone utilization, free radical quenching experiments and three-dimensional fluorescence tests, the catalytic performance of Mn-SR catalysts for ozonation was investigated. The results showed that Ca and Mg in Mn-SR play a major role in organics degradation, while MnO2 plays a complementary role in the degradation of high COD concentrations. It was confirmed that hydroxyl radicals (·OH) are the main reactive radicals in the Mn-SR catalytic ozonation system, which plays an important role in the degradation of organics in wastewater. Meanwhile, after Mn-SR was reused and regenerated for five times, the COD removal rates was still higher than 67.0%, and Mn-SR recovery rates were more than 94.7%, which showed a good stability.

Biotransformation of micropollutants in moving bed biofilm reactors under heterotrophic and autotrophic conditions

We investigated the transformation of four pharmaceuticals (Diclofenac, Naproxen, Ibuprofen and Carbamazepine) in a moving bed biofilm reactor subjected to different COD/N ratios in four experimental phases. The shift from medium to high range COD/N ratio (i.e., 5:1 to 100:1) intensified the competition between heterotrophs and nitrifying communities, leading to a transition from co-existence of heterotrophic and autotrophic conditions with high COD removal and nitrification rate in phase I to dominant heterotrophic conditions in phase II. At lower range COD/N ratios (i.e., 1:2 and 1:8) in phase III and IV, autotrophic conditions prevailed, resulting in increased nitrification rates and high abundance of amoA gene in the biofilm. Such shifts in the operating condition were accompanied by notable changes in the biofilm concentrations, composition and abundance of microbial populations as well as biodiversity in the biofilms, which collectively affected the degradation rates of the pharmaceuticals. We observed higher kinetic rates per unit of biofilm concentration under autotrophic conditions compared to heterotrophic conditions for all compounds except Naproxen, indicating the importance of nitrification in the transformation of such compounds. The results also revealed a positive relationship between biodiversity and biomass-normalized kinetic rates of most compounds.

Research on ultrafast catalytic degradation of heterocyclic compounds by the novel high entropy catalyst

Traditional refractory wastewater treatment methods have problems of low efficiency, high cost and many by-products, so it is of great significance to develop new high-efficiency refractory wastewater treatment technology. Heterogeneous catalysts were used in the catalytic ultrafast oxidation (CUFO) process to treat textile dyeing wastewater with refractory heterocyclic compounds. Composite catalysts with varying entropies were synthesized by the ultrasonic dispersion-annealing method. The high entropy catalysts exhibited superior catalytic activity and stability compared to other catalysts. Furthermore, the impact of reaction temperature (T, 350–390 °C), residence time (t, 3–17 min), oxidation coefficient (OC, 2.1–2.9), and entropy of catalyst on the COD removal were assessed. An increase in entropy of catalyst resulted in a significant enhancement of COD removal rate. At T = 390 °C and OC = 2.90, the high entropy oxides catalyst achieved the COD removal rate of 93.95 % after the 7 min reaction. Additionally, a catalytic reaction mechanism involving the CeMnCuOx solid solution heterostructure with domino catalytic ability was proposed. Overall, the results suggest that catalytic ultrafast oxidation technology is a promising option for efficiently treating refractory organic pollutants.

Electrocoagulation in a packed aluminium scraps anode reactor for mineral processing wastewater treatment

Efficient treatment and purification of mineral processing wastewater (MPW) have not been sufficiently investigated in the past though they are of great importance for sustainable mineral processing. Herein, a unique electrocoagulation (EC) reactor with aluminium scraps as anode material was developed for the treatment of real industrial MPW containing residual flotation reagents (major contributor to chemical oxygen demand, COD) and suspended particles. It was found that the active coagulants produced from the dissolution of aluminium scraps can play a key role in the purification of MPW. Under the conditions of initial pH 9, current 1 A, and processing time 90 min, the removal rate of COD was 74% while the turbidity can be almost completely removed. The mechanism lies in that most of the flotation reagents was adsorbed on the surfaces of suspended mineral particles, namely, montmorillonite, quartz, garnet, chlorite and mica, and then precipitated with the mineral particles. This innovative technology of utilizing wasted aluminium scraps to treat MPW is in line with the green development.

Performance and microbial metabolic mechanism of imidacloprid removal in a microbial electrolysis cell-integrated adsorption biological coupling system

Coke used as a filler to treat imidacloprid (IMI) wastewater by both adsorption biological coupling and microbial electrolysis cells (MEC)-adsorption biological coupling technologies, the removal efficiencies on pollutions in wastewater containing IMI were investigated, and the key functional genes related to IMI degradation pathways were also revealed. Results showed that the removal rates of COD, ammonia nitrogen, TP, and IMI under the adsorption biological coupling treatment and MEC-adsorption biological coupling treatment were 94.61–95.54%, 93.37–95.79%, 73.69–83.80%, and 100%, respectively. MEC increased the relative abundance of Proteobacteria by 9.01% and transformed the dominant bacteria from Lysobacter and Reyranella to Brevundimonas and Aquincola. Moreover, MEC up-regulated the abundance of the coding genes PK (9.30%), narG (2.26%), pstS (3.63%), and phnD (1.32%), and converted the IMI degradation products to smaller molecular weight C6H8N2 and C6H6ClNO. This study provided an important reference information for efficient treatment of IMI wastewater using the MEC-adsorption biological coupling technology.

Study on Purification Efficiency of Novel Aquatic Plant Combinations and Characteristics of Microbial Community Disturbance in Eutrophic Water Bodies

Aquatic plant restoration is an important technique for the treatment of eutrophic water bodies. There are significant differences in pollutant removal efficiency among different combinations of aquatic plant species in eutrophic water bodies. Therefore, further research on the selection of suitable combinations of aquatic plant species is of great significance for the restoration of eutrophic water bodies. This study investigated the pollutant removal efficiency and bacterial community structure of three novel combinations of aquatic plants, including Lythraceae, Nymphaea, and Myriophyllum (LNM group), Lythraceae, Nymphaea, and Hydrilla verticillata (LNH group), and Lythraceae, Nymphaea, and Vallisneria (LNV group), as well as a control group (CK group). The components of the CK group were only sediment and culture water without any plants. The results show that on one hand, the LNH group had the highest removal rate of COD (90.29%); the LNV group exhibited the highest removal rates for NH4+-N and TN, with removal rates of 61.20% and 82.94%, respectively; and there was no significant difference in the removal rate of TP among the experimental groups, except for the LNH group, which showed higher initial removal efficiency for TP. On the other hand, plant combinations had different impacts on the top 13 dominant microflora at the phylum level. Proteobacteria and Actinobacteria showed the highest removal efficiency for COD in the LNH group, while Verrucomicrobi, Chloroflex, and Acidobacteria showed higher removal efficiency for NH4+-N and TN in the LNV and LNH groups. In summary, the three different combinations of aquatic plants exhibited distinct pollutant removal characteristics, significantly altered the structure of the microbial community, and provided a theoretical basis for their practical application in the restoration of eutrophic water bodies.

Papermaking wastewater treatment coupled to 2,3-butanediol production by engineered psychrotrophic Raoultella terrigena

The simultaneous bioremediation and bioconversion of papermaking wastewater by psychrotrophic microorganisms holds great promise for developing sustainable environments and economies in cold regions. Here, the psychrotrophic bacterium Raoultella terrigena HC6 presented high endoglucanase (26.3 U/mL), xylosidase (732 U/mL), and laccase (8.07 U/mL) activities for lignocellulose deconstruction at 15 °C. mRNA monitoring and phenotypic variation analyses confirmed that cold-inducible cold shock protein A (CspA) facilitated the expression of the cel208, xynB68, and lac432 genes to increase the enzyme activities in strain HC6. Furthermore, the cspA gene-overexpressing mutant (strain HC6-cspA) was deployed in actual papermaking wastewater and achieved 44.3%, 34.1%, 18.4%, 80.2% and 100% removal rates for cellulose, hemicellulose, lignin, COD, and NO3--N at 15 °C. Simultaneously, 2,3-butanediol (2,3-BD) was produced from the effluent with a titer of 2.98 g/L and productivity of 0.154 g/L/h. This study reveals an association between the cold regulon and lignocellulolytic enzymes and provides a promising candidate for simultaneous papermaking wastewater treatment and 2,3-BD production.

Cumulative effects and metabolic characteristics of aromatic compounds in microbial cells during the biochemical treatment process of coal chemical wastewater

This study aimed to investigate the effectiveness of a biochemical treatment system for coal chemical wastewater (CCW) in degrading aromatic compounds. The study examined the degradation sequence of different compounds, including benzene series (BTEX), phenols, polycyclic aromatic hydrocarbons (PAHs), and nitrogen heterocyclic compounds (NHCs), in the system. The study also analyzed the metabolic characteristics of accumulated aromatic organic compounds in the cells of microorganisms. The results showed that the aromatic compounds were first adsorbed from water by extracellular polymers (EPS) before entering the cells. The removal rates of COD and TOC in CCW reached 95% after system operation for 8 h. BTEX and NHCs were completely degraded outside the cells within 2 h, whereas PAHs and some phenols accumulated inside the cells. The metabolic characteristics of the accumulated compounds were analyzed and found to be gradually degraded through the action of catechol dioxygenase. The study findings not only demonstrate the potential for achieving efficient biodegradation of aromatic compounds in CCW but also provide the essential theoretical underpinning for the regulation and environmentally benign treatment of such wastewater within a biochemical treatment system.

The oxidation efficiency and the microbial community analysis of a novel bio-electro-Fenton system with Fe@Co/GF composite cathode

A dual-chamber motional bio-electro-Fenton (BEF) system with Fe@Co/GF as the cathode was constructed to simultaneously degrade levofloxacin and tetracycline wastewater in both cathode and anode chambers. With an external resistance of 10 Ω, an initial cathode pH of 3, a Na2SO4 concentration of 0.5 mol/L, an initial Fe2+ concentration of 0.01 mmol/L, an aeration rate of 3*4.5 L/min, an initial levofloxacin concentration of 20 mg/L in the cathode chamber, and an initial tetracycline concentration of 20 mg/L in the anode chamber, the total levofloxacin removal rate was 91.09 % and the total mineralisation rate was 90.47 % within 24 h when Fe@Co/GF was used as the BEF system's cathode. And the total removal rates of tetracycline, COD and TOC in the anode chamber were 64.54 %, 85.45 % and 75.12 % respectively within 72 h. The BEF system's maximum power density, current density, and voltage were 12.64 W/m3, 636.94 mA/m3, and 920 mV, respectively. Furthermore, high-throughput sequencing techniques were used to examine the microbial flora that was valuable in the BEF system. This study's BEF system was capable of long-term stability and has enormous potential for treating antibiotic effluent.