10 September 2025, Volume 51 Issue 9
    

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  • Reclamation of Biogas Residue Biochar and the Research Progress in the Remediation of Water Environment Pollution
    ZHU Shijun, SHEN Shangming, WEI Ji'an, WANG Liang, LUO Haojin, LIN Tao
    Technology of Water Treatment. 2025, 51(9): 1-6.
    Abstract | Download PDF URL | Cite this Article Knowledge map Save
    Kitchen biogas residue—the solid by-product of anaerobic digestion of food waste-contains residual biomass and diverse microbial consortia. Because it is rich in nitrogen, phosphorus, potassium, amino acids and humic substances, this digestate is an excellent precursor for producing functional biochar. However, a detailed synthesis of research on digestate-derived biochar is still absent. This review therefore (i) summarises current preparation and modification techniques, (ii) explains the associated physicochemical mechanisms and (iii) evaluates recent applications of digestate biochar as an adsorbent and catalyst for water-pollution control. The analysis forms a foundation for valorising kitchen digestate and for advancing resource-recovery technologies in the water-environment sector.
  • Research Progress on the Application of Coagulation in Emulsion Wastewater
    ZHENG Huanqin, LI Zihao, SHEN Jing, WANG Shujun, DU Zhiping
    Technology of Water Treatment. 2025, 51(9): 7-14.
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    With the swift progress of China's industry, the machinery, skin care, and metal processing industries generate a considerable amount of emulsion wastewater that is hard to treat. Due to its complex composition, high chemical stability, and treatment difficulty, this type of wastewater poses a severe threat to the environment and human health. The harmless treatment of emulsion wastewater remains an area within the field of water pollution control. In this paper, the characteristics of emulsion wastewater and the mechanism of coagulation treatment for oil-containing emulsion wastewater are systematically elaborated. The application of coagulation technology in the treatment of oil-containing emulsion wastewater both domestically and internationally in recent years is reviewed. The factors influencing the efficiency of coagulation removal are discussed. The challenges and development trends of coagulation technology in dealing with emulsion wastewater are further analyzed. It provides theoretical support for addressing practical industrial wastewater treatment issues and holds significant academic value and practical significance.
  • Influencing Factors of Continuous Flow Aerobic Granular Sludge for the Formation and Stability and Enhanced Strategies: A Review
    SHENG Zihan, XU Jie, BI Xuejun, GAO Yuan, CUI Xinyue
    Technology of Water Treatment. 2025, 51(9): 15-22.
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    The development of low-carbon wastewater-treatment processes is an urgent priority. Aerobic granular sludge (AGS) technology-renowned for its high pollutant-removal efficiency, resistance to shock loading, small footprint and low energy demand-has emerged as a leading biological option. Nevertheless, slow granule formation and structural instability continue to limit large-scale implementation under continuous-flow conditions. This review systematically analyses how selective and non-selective pressures affect granulation and long-term stability in continuous-flow AGS reactors, and it identifies the specific challenges inherent to granulation in such systems. Special attention is given to recently proposed enhancement strategies, including optimisation of hydrodynamics, regulation of feast-famine regimes, improved separation of granules from flocs, seeding with specialised sludge, addition of metal ions or exogenous carriers, and integration with complementary processes. Finally, future research directions are outlined to address the remaining obstacles. The insights provided herein are expected to support both fundamental studies and practical applications of AGS technology.
  • Research Progress on Mitigating Ultrafiltration Membrane Fouling Based on Typical Advanced Oxidation Processes
    XING Sichu, ZHOU Chundi, SUI Minghao
    Technology of Water Treatment. 2025, 51(9): 23-28.
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    Ultrafiltration membrane separation technology has been widely applied in the field of water treatment, yet membrane fouling remains a major obstacle to its further development. In recent years, advanced oxidation processes (AOPs) have shown significant potential in mitigating ultrafiltration membrane fouling. This paper primarily analyzes the principles and characteristics of ozone (O3), persulfate (PS), and other advanced oxidation technologies, including permanganate, chlorine and UV-assisted AOPs. The research progress of these AOPs in alleviating ultrafiltration membrane fouling is reviewed. The results indicate that AOPs significantly improve permeate flux and extend the service life of ultrafiltration membranes, with ozone and persulfate systems performing particularly well. Finally, the paper summarizes the technical advantages of AOPs in ultrafiltration membrane hybrid processes and provides an outlook on their future development prospects.
  • Effect and Mechanism of Mn2+ Activation of HCO3-/H2O2 on Degradation of Sulfamethoxazole in Water
    LIU Qiang, WU Yun, JIANG Chengchun
    Technology of Water Treatment. 2025, 51(9): 29-34.
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    The effects of initial concentrations of H2O2, HCO3-, Mn2+ and pH on the degradation of sulfamethoxazole in water in the Mn2+ activated HCO3-/H2O2(BAP) system were investigated in this paper. The radical quenching experiment and EPR analysis revealed the degradation mechanism of sulfamethoxazole in the manganese activated BAP system. The experimental results showed that hydroxyl radical (·OH), carbonate radical (CO3·-), superoxide radical (O2·-) and singlet oxygen (1O2) all participated in the degradation process. By attacking the molecular structure of sulfamethoxazole, they gradually decomposed and finally mineralized into non-toxic small molecule substances. This study not only provides a new idea and method for the treatment of refractory organic pollutants such as sulfamethoxazole, but also makes the application of green and sustainable advanced oxidation technology of BAP possible. Future studies will further optimize the performance of the Manganese-activated BAP system, explore its application prospects in practical water treatment projects, and evaluate its environmental benefits and economic feasibility.
  • Study on Degradation of Tetracycline by Mn-Doped Straw Biochar Activated Persulfate
    LI Yafeng, CUI Keqing, FU Xiangyu
    Technology of Water Treatment. 2025, 51(9): 35-40.
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    Manganese-doped biochar (Mn-BC) was synthesised from corn-stover powder and manganese chloride tetrahydrate (MnCl2·4H2O) via an impregnation-pyrolysis route and then applied to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. Catalyst performance depended on the Mn precursor loading, and the optimum mass ratio of corn stover to MnCl2·4H2O was 1:1. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and complementary analyses confirmed successful Mn incorporation and the formation of a porous structure. Under optimal reaction conditions (Mn-BC 1.5 g/L, PMS 3 mmol/L, TC 20 mg/L, pH=6), 88.6% of TC was removed within 30 min. The catalyst remained effective after three reuse cycles, still achieving 87.5% removal. Radical-quenching experiments demonstrated that sulfate radicals (SO4•-) were the primary oxidising species, whereas hydroxyl radicals (•OH) contributed to a lesser extent.
  • Adsorption Characteristics of Modified Graphene Oxide on Tetracycline Antibiotics in Water
    PENG Bo, OUYANG Feng, LIU Liao, WANG Songtao, TANG Chengrui, HE Yang
    Technology of Water Treatment. 2025, 51(9): 41-47.
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    Tetracycline antibiotics are widely employed in human and veterinary medicine, yet the resulting effluents are difficult to treat by conventional processes. To address this issue, graphene oxide (GO) and chitosan (CS) were combined by solution blending and casting to produce a graphene-oxide-chitosan film (GOCSF) and graphene-oxide-chitosan particles (GOCSP). The influence of precursor ratios and solution pH on the preparation and adsorption performance of both sorbents was systematically examined. Morphological and physicochemical properties were characterised by SEM-EDS, BET, XPS and FT-IR analyses. Adsorption of tetracycline (TC) and chlortetracycline (CTC) was evaluated through kinetic and isotherm modelling. GOCSP exhibited superior structural integrity, larger specific surface area and greater cross-linking density than GOCSF. Both sorbents performed optimally at pH 5. Maximum adsorption capacities of GOCSP were 3.69 mg/g for TC and 2.51 mg/g for CTC, while GOCSF achieved 3.50 and 2.25 mg/g, respectively. Adsorption followed a pseudo-second-order kinetic model and was well described by the Langmuir isotherm, indicating monolayer, endothermic uptake. Owing to their high efficiency, environmental benignity and ease of regeneration, these GO/CS composites are promising adsorbents for treating tetracycline-contaminated wastewater.
  • Mitigation Mechanism of Membrane Fouling of Ammonium Sulfate Wastewater by Trace Amounts of Fenton Reagent
    JIN Keyu, YANG Yifan, ZHANG Wenjuan, QU Jiani, WANG Jinwen, MIAO Rui
    Technology of Water Treatment. 2025, 51(9): 48-52.
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    To alleviate ultrafiltration (UF) membrane fouling during the treatment of ammonium-sulphate wastewater generated by rare-earth smelting, trace-dosage Fenton pre-oxidation was applied and its effects were systematically evaluated. Fouling kinetics were linked to alterations in wastewater organic matter to elucidate the mitigation mechanism. Both the fouling rate and the proportion of irreversible fouling declined once H2O2 and Fe2+ dosages exceeded 0.17 and 0.28 mg/L, respectively, and continued to fall with further increases in reagent concentration. At 0.68 mg/L H2O2 and 1.12 mg/L Fe2+, total fouling resistance fell by more than 40%, accompanied by a substantial rise in organic-matter removal. This improvement is attributed to the synergistic oxidative and coagulative actions of the Fenton process, which transformed the organic matter, reduced its affinity for the membrane surface and produced a looser, less compact fouling layer.
  • Study on the Performance of Phosphate Adsorption by Composite Biochar of Phosphogypsum and Poplar Leaf
    LIANG Yu, LI Fengyu, HE Dongsheng
    Technology of Water Treatment. 2025, 51(9): 53-59.
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    Phosphorus-rich effluents from industrial activities threaten aquatic ecosystems. Here, a composite biochar (PG-PL) synthesised from industrial phosphogypsum (PG) and poplar leaves (PL) was evaluated for phosphate removal from water. Scanning electron microscopy and Fourier-transform infrared spectroscopy confirmed successful integration of PG with PL. The biochar produced at 700 °C with a PG:PL mass ratio of 1:2 exhibited the highest sorption capacity. Under optimal conditions (initial phosphate 50 mg/L, pH 8, adsorbent dose 3.5 g/L, 25 °C, 6 h), phosphate uptake followed a pseudo-second-order kinetic model and fitted the Langmuir isotherm, indicating chemisorption, with a maximum capacity of 87.34 mg/g. After adsorption, PG-PL can be applied to soil as a phosphorus fertiliser, closing the nutrient loop. These results demonstrate that PG-PL is a promising, low-cost adsorbent for phosphate remediation.
  • Ultrafiltration Membrane Technology for the Pretreatment of Salt Lake Brine
    LI Yan, WANG Min, YANG Hongjun, ZHAO Youjing
    Technology of Water Treatment. 2025, 51(9): 60-66.
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    This study employed ultrafiltration (UF) technology for the pretreatment of salt lake brine, systematically evaluating the influence of operational parameters (e.g., salinity, temperature, recovery rate) and UF processes on the retention efficiency of silicon and organic pollutants. Results demonstrated that the Titan-NF membrane achieved optimal pretreatment performance at a brine salinity of 20 g/L and a feed temperature of 20°C. Under higher salinity conditions (100 g/L) with a 20°C feed temperature and 62% recovery rate, the BFUF300 hollow fiber UF membrane exhibited superior performance. Comparative analysis revealed that both membranes significantly outperformed conventional multimedia filtration and standard UF pretreatment methods, offering a viable strategy for sustainable lithium extraction from salt lake brines.
  • Study on the Multiple Adsorption Mechanisms and High-Efficiency Performance of Fe-ZIF-8 Modified Biochar for Tetracycline Removal from Wastewater
    LI Lang, YANG Yanqun, SONG Meifang, HUANG Guoyan, ZHANG Zejun, QUAN Yong
    Technology of Water Treatment. 2025, 51(9): 67-72.
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    Escalating antibiotic contamination demands high-performance adsorbents for water treatment. In this work, biochar produced from discarded apple-tree branches was functionalised with the metal-organic framework Fe-ZIF-8 to form the composite FeZn-8@BC. Incorporation of Fe-ZIF-8 supplied abundant active sites and increased the tetracycline (TC) adsorption capacity to 473 mg/g, surpassing most conventional sorbents. Adsorption kinetics followed a pseudo-second-order model, indicating chemisorption, whereas equilibrium data conformed to the Freundlich isotherm, consistent with multilayer uptake. Mechanistic analysis revealed synergistic contributions from surface complexation, electrostatic attraction, π-π interactions and hydrogen bonding, with metal-ligand coordination further enhancing affinity and selectivity. The composite's facile, environmentally benign synthesis and excellent recyclability underscore its promise for TC removal from wastewater.
  • Samarium-Doping-Modulated High-Surface-Area MnOx Film Electrodes for Lithium Extraction from Salt Lakes
    ZHANG Xinglong, WANG Peifen, AN Xiaowei, MA Xuli, LUO Jialiang
    Technology of Water Treatment. 2025, 51(9): 73-80.
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    To overcome the low lithium concentration and high Mg/Li ratio characteristic of salt-lake brines, we synthesised a Sm-doped LiMnOx film electrode by redox co-precipitation and assessed its performance for selective Li⁺ recovery via electrochemically switched ion exchange (ESIX). Incorporation of Sm³⁺ enlarged the specific surface area to 192.90 m2/g, an 84.65% increase relative to pristine MnOx (104.47 m2/g), and raised the Li⁺ adsorption capacity from 5.3 to 18.18 mg/g(2.4-fold). In quaternary Li⁺/Mg2⁺/Ca2⁺/Na⁺ solutions, separation factors for Li⁺ over Mg2⁺, Ca2⁺ and Na⁺ reached 7.62, 8.90 and 9.53, respectively. The electrode retained 88 % of its initial capacity after ten adsorption-desorption cycles, indicating good stability. Performance gains are attributed to Sm³⁺-induced exfoliation of MnOx, which enhanced electrode conductivity and reduced ion-transport resistance. These findings underscore the promise of Sm-doped MnOx film electrodes for efficient lithium extraction from salt-lake brines.
  • Adsorption Performance for Chlorophenols by Polymerised Membranes of Carbazole-Based Microporous Organic Networks
    WANG Yulin, ZHOU Kailian, CHEN Jixuan, ZHANG Jiaqiuzi, HUANG Donglan, QIU Xiuzhen
    Technology of Water Treatment. 2025, 51(9): 81-86.
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    Chlorophenols (CPs) in water represent a class of pollutants for their toxicity and carcinogenic properties, stringently regulated by the state. Consequently, the treatment of phenol-laden wastewater is a pivotal concern in wastewater management. In this experiment, we synthesized carbazole-based microporous organic networks (MONs) utilizing 3,6-dibromocarbazole and 1,4-diethynylbenzene as precursors. Subsequently, these MONs were integrated with polyvinylidene fluoride(PVDF) to form a polymeric membrane (MONs-M), tailored for the adsorption of diverse chlorophenols from water. To elucidate the structural and functional characteristics of both MONs and MONs-M, we employed scanning electron microscopy, infrared spectroscopy, and N2 adsorption-desorption experiments. The obtained material exhibited an advantageous network architecture, characterized by a high specific surface area and well-defined pore dimensions, favorable for the effective capture of target molecules. We investigated the impact of pH, adsorption temperature, and salt concentration on the adsorption efficiency of MONs-M. Furthermore, we delved into the adsorption performance and recyclability of MONs-M towards three specific chlorophenols: p-chlorophenol (p-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP). Under optimized conditions (pH 8, 30 °C, and 0 mg/L NaCl), the maximum adsorption capacities achieved were 42.28 mg/g for p-CP, 61.67 mg/g for 2,4-DCP, and 72.61 mg/g for 2,4,6-TCP, respectively. The adsorption performance of MONs-M showed only a slight downward trend after five repeated uses. This result highlights the potential of MONs-M in the field of chlorobenzene phenolic compounds adsorption.
  • Study on the Loading Efficiency and Ammonia Removal Performance of Manganese Oxide Filter Material with Different Gelling Agents
    XUE Mengchen, XIONG Zikang, CHENG Ya, HUANG Tinglin
    Technology of Water Treatment. 2025, 51(9): 87-94.
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    In order to strengthen the surface membrane load strength of catalytic oxidation of ammonia-removing manganese oxide filter material in groundwater treatment. In the experimental and pilot experiments, the selected gelling agent and the blank group of manganese oxide filter material were applied to the circulation-in-line filter column system, and the loading efficiency of different gelling agents on manganese oxide and the removal effect of ammonia nitrogen under different conditions were investigated. The results show that the two filter columns with gelling agent have better effect of removing ammonia in the early stage. During the operation of the later acyclical system, under different filtration rates and different initial ammonia concentrations, glue powder and PAM filter column have stronger ammonia removal capacity than blank filter column. Under the condition of the presence of manganese ion, the ammonia removal rates of the first 20 cm of the filter layer of blank, glue powder and PAM filter column are 51.9%, 70.10% and 63.55%, respectively. Glue powder and PAM filter column are less susceptible to backwashing than blank filter column, and the ammonia removal ability is more stable. The change of ammonia removal in the mature oxide film of three filter columns was observed, and it was found that the gelling agent had no great influence on the removal capacity of ammonia. Comparing the membrane load and membrane load strength of the filter material in different periods, it was found that the membrane load of glue powder filter column was higher than that of the other two filter columns, and the membrane load strength of glue powder and PAM filter column was higher than that of the blank filter column. In combination, it is speculated that the filter column with gelling agent added has a better ammonia removal effect because of its higher membrane load strength and membrane volume, which makes the filter column more adaptable to the changes of different treatment conditions, and the ammonia removal performance of the filter column remains in the high efficiency range.
  • Effects of Ofloxacin on the Nitrogen Removal and N2O Release by Thermophilic Biological Denitrification
    JING Yanyan, PANG Zhengqi, FAN Xinying
    Technology of Water Treatment. 2025, 51(9): 95-100.
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    Thermophilic biological denitrification (TBD) offers high nitrogen-removal efficiency while generating low levels of greenhouse gases. However, the effect of the emerging contaminant ofloxacin (OFL) on TBD performance has not been thoroughly investigated. In this study, TBD reactors were fed with influent OFL concentrations between 0 and 8.0 mg/L to examine impacts on nitrogen removal and N2O emissions. OFL impaired pollutant degradation and denitrification; ammonium removal was inhibited only at 8.0 mg/L, whereas total nitrogen (TN) removal declined at concentrations as low as 0.2 mg/L. N2O production increased with OFL addition, rising to 8.51 µg /min at 8.0 mg/L. OFL exposure reduced mixed-liquor suspended solids and organic content, elevated extracellular polymeric substance (EPS) levels, and worsened sludge settleability. OFL removal efficiency within the reactors decreased as the influent concentration increased. In addition, OFL suppressed intracellular-polymer synthesis, thereby limiting electron donors required for denitrification. These findings improve the understanding of OFL behaviour in thermophilic systems and provide a theoretical basis for optimising TBD processes treating antibiotic-laden wastewater.
  • Study on the Treatment Effect and Biological Toxicity of Wastewater from Intensive Cattle Farms Based on Flocculation Technology
    DANG Xin, LAN Tian, ZHANG Li, LI Jiao, ZHANG Lechuan, HONG Mei
    Technology of Water Treatment. 2025, 51(9): 101-106.
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    Rapid development of the large-scale cattle industry has led to increasingly prominent environmental problems caused by livestock manure. This study aims to treat the wastewater from intensive cattle farms by flocculation technology, with a focus on the removal efficiencies of suspended solids (SS), chemical oxygen demand (COD), total phosphorus (TP), and ammonia nitrogen by different flocculants (CaO、FeSO4、MgSO4、PAC、PAM) and their combinations. Finally, the biological toxicity of the treated seeds was evaluated using germination experiments. The results indicated that FeSO4 at a concentration of 0.4% achieved the highest removal efficiency for SS, with a removal rate of 80.35%. When 5% CaO was added, the total phosphorus removal rate reached 93.53%. The treatment costs for FeSO4 and CaO were relatively low, at 1.4 yuan/m3 and 2.4 yuan/m3, respectively. After treatment with the combination of 2% CaO and 0.4% PAC, the SS removal rate reached 76.31%, with a treatment cost of 18.32 yuan/m3. After diluting the supernatant 1 times, the germination rate of seeds reached 39.33%, which promoted the growth of roots. This study provides a technical reference for efficient and cost-effective treatment of cattle manure from intensive farms, which has significant environmental and economic implications.
  • Effect of Carbon Source Supply form and Mode on Nitrate Removal Behavior in Hydrogen-Based Membrane Biofilm Reactor
    CHENG Weidong, DAI Xingru, ZHANG Ying, LIU Yuhui, JIANG Minmin
    Technology of Water Treatment. 2025, 51(9): 107-112.
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    Hydrogen-based membrane biofilm reactors (H2-MBfRs) are regarded as effective systems for removing nitrate (NO3⁻) from water. Nevertheless, the type of carbon source used to buffer alkalinity and its delivery mode strongly influence bulk pH and, in turn, denitrification kinetics within the biofilm. In this study, laboratory experiments coupled with a one-dimensional biofilm model were conducted to evaluate denitrification under several carbon-supply strategies. Both extra-membrane and intra-membrane CO2 dosing provided the highest performance, achieving complete nitrate removal with no detectable nitrite accumulation. Under these two CO2 modes, denitrification activity across the biofilm was largely insensitive to pH, whereas the remaining scenarios experienced pH-dependent inhibition. Model simulations further showed that pH control enhanced denitrification in three of the four cases when compared with operation relying solely on NaHCO3. Moreover, the combination of CO2 addition and pH control conferred the greatest resilience to hydraulic and nitrogen shock loads.
  • Study on Performance of Catalytic Ozonation for the Advanced Treatment of Maotai-Flavor Liquor-Making Wastewater
    MA Guoxin, QIN Zhikai, LOU Jinming, WANG Panxin, QU Zhiming, YUAN Yue
    Technology of Water Treatment. 2025, 51(9): 113-118.
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    In this study, secondary-biological effluent from a distillery in Guizhou was treated with tailor-made supported catalysts. Bimetallic formulations outperformed monometallic ones; specifically, a Cu-Mn catalyst with a Cu:Mn molar ratio of 1: 1 achieved the greatest removals of chemical oxygen demand (COD) and total organic carbon (TOC), 53.8% and 54.6%, respectively. Treatment efficacy was also compared with single coagulation and with coagulation followed by catalytic ozonation. Although 20 mg/L of coagulant afforded the highest COD and TOC removal in stand-alone coagulation, the pretreatment suppressed subsequent catalytic ozonation. Direct catalytic ozonation over the Cu-Mn catalyst therefore constitutes the most effective advanced treatment for Maotai-flavour liquor wastewater.
  • New Insight into the Impact of Antidepressant Fluoxetine on Biological Sewage Treatment
    LIN Hengzhen, YU Shuyan
    Technology of Water Treatment. 2025, 51(9): 119-124.
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    Laboratory-scale sequencing batch reactors (SBRs) were operated to elucidate the influence of the emerging antidepressant fluoxetine (FLX) on enhanced biological phosphorus removal (EBPR). Influent FLX concentrations were systematically varied to assess reactor performance, sludge characteristics and microbial metabolism. The effect was dose-dependent: concentrations ≤ 1.0 mg/L had negligible impact, whereas ≥ 1.0 mg/L significantly decreased nutrient removal, reduced mixed-liquor suspended solids and lowered organic content. Elevated FLX levels also stimulated the secretion of extracellular polymeric substances (EPS), increasing their protein and polysaccharide fractions, presumably as a self-protective response. At 5.0 mg/L FLX, the specific oxygen uptake rate (SOUR) declined to 14.5 mg O₂/(g VSS·h), while reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release rose to 125% and 134% of control values, respectively, indicating oxidative stress and membrane damage. Although reactor performance partially recovered after FLX withdrawal, efficiency remained below the initial level. These findings clarify FLX behaviour in EBPR systems and provide a basis for its effective removal.
  • Study on Humic Acid Iron Complex Mediated Extracellular Electron Transfer to Enhance Nitrogen Transformation
    GAO Chenteng, SONG Xinshan, LI Hongwei
    Technology of Water Treatment. 2025, 51(9): 125-130.
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    Iron redox-mediated nitrogen transformation has wide application potential in water treatment. Nevertheless, practical implementation faces challenges such as the loss of free iron ions, their inhibitory effects on microbial activity, and the low efficiency of extracellular electron transfer (EET). In this study, a humic acid iron complex (HA-Fe) was synthesized by introducing humic acid (HA) to immobilize the iron source and investigate its impact on nitrate removal. The HA-Fe group exhibited the highest denitrification performance, achieving a total nitrogen (TN) removal rate constant of 0.379 4 d-1, which was 2.40, 1.90, and 1.71 times that of the CK, HA, and Fe groups, respectively. These findings can be attributed to the additional reactive sites provided by HA-Fe, which promotes the iron cycle via EET and facilitates redox reactions in the respiratory chain to enhance nitrogen conversion. Under low C/N conditions, the TN removal rate of the HA-Fe group reached 75.44%, surpassing that of the CK, HA, and Fe groups by factors of 1.35, 1.27, and 1.08, respectively. Moreover, the HA-Fe group increased the Zeta potential and extracellular polymer (EPS) production, resulting in greater microbial aggregate stability. Community analysis further revealed elevated abundances of autotrophic denitrifying bacteria and electroactive bacteria in the HA-Fe system, confirming that HA-Fe strengthened the EET process and enabled mutualistic interactions between electroactive and denitrifying bacteria.
  • Mechanism on Simultaneous Removal of Trace Antibiotics and Shortcut Nitrification in Membrane Aerated Biofilm Reactor (MABR) Systems
    GE Pinging, YANG Xiaolin, LIU Xingyu, SHI Chenguang, HUANG Jihong, TIAN Hailong
    Technology of Water Treatment. 2025, 51(9): 131-136.
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    Trace antibiotics in municipal wastewater can disrupt biological nitrogen removal, yet their combined effects on shortcut nitrification and antibiotic abatement are not fully understood. This study therefore examined the influence of sulfamethoxazole (SMX), roxithromycin (ROX) and levofloxacin (LEV) on shortcut nitrification in a membrane-aerated biofilm reactor (MABR). The antibiotics increased the micro-environmental pH and dissolved-oxygen concentration, which stimulated nitrification but reduced the NO2--N accumulation rate from 87.7%±2.2% (control) to 54.6%±4.2%. Removal of SMX (87.0%±4.4%) markedly exceeded that of ROX (30.0%±7.2%) and LEV (10.0%±4.3%). Metagenomic and metabolomic analyses identified resistance genes (macB, tet(58), bcrA, novA, evgS and oleC) and the up-regulation of polycyclic-aromatic-hydrocarbon degradation, benzoxazinoid biosynthesis and aminobenzoate degradation pathways as key contributors to SMX (and partial ROX) transformation. Residual ROX and LEV were the main factors impairing shortcut nitrification. Operational strategies that lower pH and moderate oxygen supply are therefore recommended to sustain MABR performance and to enable subsequent partial-nitritation/anammox (PN/A) treatment. These findings support the application of MABRs for concurrent antibiotic removal and shortcut nitrification.
  • Treatment of Landfill Leachate by Electrochemistry with Three-Dimensional Particle Electrode
    ZHANG Weizheng, WANG Lei, LENG Shaowei, LI Ning, LIU Ying, ZHAO Mengjuan
    Technology of Water Treatment. 2025, 51(9): 137-141.
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    Due to the rapid expansion of the social economy, the volume of municipal solid waste increases annually, leading to landfill disposal that generates leachate with a complex composition containing toxic and hazardous substances. Experimental results indicated that, under optimal conditions, three-dimensional electrode electrochemical technology effectively treated this landfill leachate, achieving removal rates of 99.0%, 75.4%, 67.5%, and 51.9% for chromaticity, UV254, total organic carbon (TOC), and chemical oxygen demand (COD), respectively. This study provides a theoretical foundation for subsequent pilot-scale investigations and highlights promising prospects for three-dimensional electrode electrochemistry.
  • Project Example of 4, 6-Dichloropyrimidine Production Wastewater Treatment
    ZHANG Xuehao, HAN Yuyuan, LIU Shuntong, LIU Jintian, LI Zenghui, DAI Jie
    Technology of Water Treatment. 2025, 51(9): 142-145.
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    The 4,6-dichloropyrimidine production wastewater, characterized by high chemical oxygen demand (COD) and high ammonia nitrogen (NH3-N) content, was treated using a combined process consisting of iron-carbon microelectrolysis, Fenton oxidation, two-stage anaerobic treatment, and three-stage contact oxidation, with a designed treatment capacity of 120 m3/d. Continuous operation over 90 d demonstrated that under relatively stable influent water quality conditions, the effluent COD and NH3-N concentrations were consistently below 200 mg/L and 45 mg/L, respectively, achieving removal efficiencies of 97% and 95%. All effluent water quality parameters met the influent water quality limits required by the park sewage treatment plant. Engineering practice has shown that this treatment system operates stably, is user-friendly, and delivers favorable economic and environmental benefits. Therefore, it is well-suited for the treatment of 4,6-dichloropyrimidine production wastewater. The operational experience gained from this project can serve as a valuable reference for similar wastewater treatment initiatives dealing with high COD and high NH3-N levels.
  • Research on the Design and Application of Non-Powered Tubular Dynamic Mixer
    GE Shaogen, ZHENG Leilei, ZHANG Fei, TANG Yulin, ZHEN Shucong
    Technology of Water Treatment. 2025, 51(9): 146-152.
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    To overcome the limited shock-load tolerance and high energy demand of conventional mixers, we designed a non-powered tubular dynamic mixer in which the fixed guide elements of a tubular static mixer were replaced with an adjustable orifice plate. Pilot-scale trials were conducted in two municipal waterworks, where the new device was operated in parallel with a mechanical agitator and a tubular static mixer. The non-powered mixer achieved an annual mean effluent turbidity of 0.70 NTU, a coagulant dose of 68.94 mg/L, a CODMn of 2.18 mg/L and a residual aluminium concentration of 0.078 mg/L. These values were markedly lower than those obtained with the tubular static mixer (1.71 NTU, 85.16 mg/L, 2.73 mg/L and 0.133 mg/L, respectively) and the mechanical agitator (1.32 NTU, 80.03 mg/L 2.39 mg/L and 0.091 mg/L). Because the proposed mixer operates without an external power supply, it consumes no electricity, requires less maintenance than mechanical agitators, and provides superior mixing relative to tubular static mixers. Accordingly, it offers considerable potential for large-scale adoption in water-treatment facilities.
  • A Project Case of MBBR and ACCA Process Used in Municipal Wastewater Treatment Plant Upgrading and Renovation
    WANG Hongyan, MA Haoliang, ZHAI Mingge, WANG Yongjie, XU Hongbin
    Technology of Water Treatment. 2025, 51(9): 153-156.
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    Stricter effluent discharge regulations have imposed new challenges on wastewater treatment technologies. A sewage treatment plant in Henan Province has implemented an upgraded MBBR+ACCA process. Operational data indicate removal efficiencies of 95.16% for COD, 99.45% for NH3-N, 77.31% for TN, and 94.75% for TP. The corresponding average effluent concentrations were 11.2 mg/L for COD, 0.18 mg/L for NH3-N, 8.47 mg/L for TN, and 0.15 mg/L for TP. Notably, the effluent COD, NH3-N, and TP levels comply with Grade III of the Environmental Quality Standards for Surface Water (GB 3838–2002). The process demonstrates stable operation and effective treatment, with an incremental operating cost of approximately 0.50 yuan/m3, comprising 0.11 yuan/m3 for electricity and 0.39 yuan/m3 for activated coke. These findings offer valuable insights for the retrofitting of other wastewater treatment facilities and the reuse of reclaimed water.
Administrated:
China National BlueStar (Group) Co., Ltd
Sponsored by:
Hangzhou Water Treatment Technology Development Center Co., Ltd
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Editorial Department of “Technology of Water Treatment”
Chief Editor：
Gao Congjie (Academician of Chinese Academy of Engineering)
Editor in Chief：Wang Qi
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