10 July 2025, Volume 6 Issue 7
    

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  • Research Progress in the Treatment of Dye Wastewater by Supported Modified Ag3PO4 Under Visible Light Catalysis
    BAN Fuchen, WEI Yu
    Technology of Water Treatment. 2025, 6(7): 1-6.
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    This paper provides a comprehensive review of dye wastewater treatment using supported and modified Ag3PO4 under visible-light irradiation. Although Ag3PO4 exhibits a high quantum yield, its catalytic performance is constrained by severe photocorrosion, a wide band gap, limited spectral response range, and short photogenerated charge-carrier lifetimes. Consequently, this review emphasizes the application of Ag3PO4 as a photocatalyst in dye wastewater treatment, underscoring the advantages of its supported, modified form in terms of catalytic activity, stability, and reusability. Recent progress is summarized by examining different support materials, modification methodologies, and reaction conditions influencing catalytic performance. Finally, future research directions are outlined, along with recommendations for optimizing the structure of supported and modified Ag3PO4 catalysts to enhance photocatalytic efficiency and stability, thereby guiding advances in dye wastewater treatment technology.
  • Research Status of Photothermal Materials in the Field of Solar Desalination
    HAN Mingcai, YU Xiaoli, BAO Guangkuo
    Technology of Water Treatment. 2025, 6(7): 7-13.
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    With the increasing shortage of fresh water resources worldwide, solar-driven desalination technology has garnered widespread attention for its environmental friendliness and sustainability,as the core material of this technology, photothermal materials have been extensively studied in the field of desalination. The performance characteristics of different types of photothermal materials and their applications in seawater desalination were studied, and the research status and challenges of photothermal materials in seawater desalination were elaborated. the future, the development of photothermal materials with higher light-to-heat conversion efficiency, better stability, and anti-fouling properties, as well as the of desalination system design and integration to reduce costs and promote large-scale application, will be the main development direction of photothermal materials in the field of desination. This holds significant strategic importance for alleviating the global fresh water resource crisis.
  • Research and Application Progress of Entrapped AnAOB for Wastewater Nitrogen Removal
    ZHONG Zhongquan, ZHAO Lili, YANG Ping
    Technology of Water Treatment. 2025, 6(7): 14-20.
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    Research on nitrogen removal from wastewater using entrapped slow-growing anammox bacteria has attracted increasing attention, particularly regarding its performance. This paper summarizes the advancements in research and applications of this technology, highlighting key issues that warrant further consideration. It reviews and discusses the materials used for entrapping anammox bacteria, the single-stage and two-stage partial nitrification-anammox processes, reactor configurations, different types of entrapped anammox bacteria, pilot-scale studies, and engineering applications. Additionally, the paper offers recommendations for future research and applications.
  • Progress on the Degradation of Organic Wastewater by Iron-Based Bimetallic Activated Persulfate
    SUN Deyang, WANG Hongbo, SONG Lianxin, XU Xintao, MA Jinlong, Li Xiaochen
    Technology of Water Treatment. 2025, 6(7): 21-26.
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    Alternative chemical treatment methods, including radical- and non-radical-based advanced oxidation processes, have drawn increasing attention in water treatment. In particular, the Fenton-like bimetallic reaction centered on iron and sulfate radical-based oxidation are widely applied to remove organic contaminants. Transition metals, including iron, serve as common persulfate activators in remediating organic pollution, and forming bimetallic complexes between iron and other metals fine-tunes the catalyst's electronic structure and active sites. Consequently, iron-based bimetallic catalysts frequently exhibit enhanced stability, catalytic potency, and recyclability. Drawing on current domestic and international research, this paper reviews recent developments in the fabrication, activation mechanism, and applications of iron-supported bimetallic catalysts for pollutant degradation. Key factors affecting the catalyst's stability and the activation efficiency of peroxodisulfate-based systems are also discussed, along with possible future directions for organic wastewater treatment using these catalysts.
  • Research Progress of Ultrasonic Oxidation Technology in Wastewater Treatment
    LIU Wei, TIAN Zhenhua, MA Jinju, LI Huabei, YAO Xinding
    Technology of Water Treatment. 2025, 6(7): 27-33.
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    Ultrasonic oxidation, an advanced oxidation process, offers advantages such as simple operation, rapid reaction rates, and mild operating conditions. However, it also has drawbacks, including low pollutant degradation efficiency and incomplete mineralization. This article systematically examines the mechanisms underlying ultrasonic cavitation-including localized high temperature, high pressure, charge generation, luminescence, and supercritical oxidation—that collectively enhance pollutant degradation. It further explores how various parameters (pollutant properties, ultrasound frequency, electrical power, pH, solution composition, and temperature) influence pollutant removal efficacy. Additionally, the synergistic oxidation theories, technical attributes, and future development trends of integrating ultrasonic oxidation with other oxidative processes are discussed. As an emerging hybrid advanced oxidation technology, ultrasonic synergistic oxidation is gaining significant attention both domestically and internationally and is expected to see broader application in wastewater treatment.
  • Construction of Electroactive SPS/CNTs/PVA/LMO Permeable Membrane and Selective Separation of Lithium Ion
    WANG Zhi, SUN Haidong, YAN Xiongzhong, YANG Futing, DU Xiao, HAO Xiaogang
    Technology of Water Treatment. 2025, 6(7): 34-40.
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    With the rapid growth in demand for lithium resources in the new energy sector, extracting lithium ions from salt-lake brine is critical to ensuring an adequate supply. In this study, an electroactive lithium-ion permselective membrane (SPS/CNTs/PVA/LMO) was prepared using a layer-by-layer assembly and permeation-filling approach. Lithium manganate (LMO) served as the Li⁺ electroactive material, carbon nanotubes (CNTs) acted as electron conductors, polyvinyl alcohol (PVA) was used as a binder, and sulfonated polystyrene (SPS) functioned as a filler. The resulting membrane was applied in an electronically switched ion-selective permeation (ESIP) system to extract Li⁺. The voltage operating parameters of the ESIP system were optimized, and the SPS/CNTs/PVA/LMO membrane's selective separation performance for Li⁺ was evaluated. Under adsorption and desorption voltages of 0.8 V and 2.4 V, respectively, the Li⁺ permeation flux reached 0.052 mol/(m2·h) , while the selectivity was 3.91.
  • Preparation of Composite Loose Nanofiltration membrane for Treatment of Micro-polluted Water
    JIANG Shuhong
    Technology of Water Treatment. 2025, 6(7): 41-46.
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    Using an alumina ceramic membrane as a substrate, this study employed polydopamine/polyethyleneimine (PDA/PEI) co-deposition for surface modification, followed by interfacial polymerization with 1,3,5-benzenetricarbonyl chloride to fabricate an organic-ceramic composite loose nanofiltration membrane. Surface characterization via scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) confirmed successful coating deposition and provided insight into the influence of the PDA/PEI mass ratio on filtration performance. A TOPSIS-GRA approach was then utilized to quantitatively assess membrane efficiency. Results showd that the organic layer effectively reduced pore size and enhanced surface uniformity. At 0.1 MPa, a PDA/PEI ratio of 1:1 achieved a pure water flux of 36.62 L/(m²·h), with organic and conductivity rejections reaching 50% and 17.34%, respectively—substantially surpassing the ceramic-based membrane's values of 4.55% and 1.89%. Among the performance metrics, inorganic matter retention and operating flux held the highest weight, and under these conditions, the composite membrane exhibited its optimal overall performance at a PDA/PEI ratio of 1:1.
  • Preparation of Compound Slow-Release Carbon Source and Its Denitrification and Nitrogen Removal Performance
    XU Li, SUI Yuan, DONG Yue
    Technology of Water Treatment. 2025, 6(7): 47-52.
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    To address the low COD release and limited sustainability of corncob cellulose as a carbon source, this study examined how alkali treatment affects corncob carbon release, identified an effective treatment method, and employed embedding technology to enhance its sustained-release properties. Both unmodified corncob and corncob treated with 1%, 3%, or 5% NaOH were evaluated to determine their COD release performance. Various proportions of polyvinyl alcohol (PVA) and sodium alginate (SA) were tested to identify the optimal embedding matrix ratio. The impacts of temperature, stirring intensity, and dosage on static denitrification and nitrogen removal by compound slow-release P-S-C particles were also investigated. Experimental results revealed that corncob treated with 5% NaOH achieved the highest carbon release (128.59 mg/(g·L)), making it more suitable as an internal carbon source. Meanwhile, P-S-C particles with a PVA:SA ratio (P:S) of 8:1 showed excellent sustained-release behavior, reducing the maximum carbon release rate by 71.20% compared with non-embedded corncob. Under controlled conditions of 25~30 °C, a rotational speed of 50~100 r/min, and a dosage of 5 g/250 mL, carbon source waste was minimized, and the NO3--N removal rate remained high. Overall, corncob modified with 5% NaOH was found to be the most suitable internal carbon source, and P:S=8:1 was the optimal embedding ratio.
  • Preparation and Application Effect Analysis of Carboxymethyl Chitosan Composite Corrosion Inhibitor
    CHENG Jun, TIAN Zeyang, PEI Pei, WANG Guohong, WANG Yanwei
    Technology of Water Treatment. 2025, 6(7): 53-57.
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    Carboxymethyl chitosan (CMCS) was synthesized via chemical modification of chitosan using chloroacetic acid and characterized by Fourier-transform infrared spectroscopy (FTIR). The corrosion inhibition efficiencies of three inorganic inhibitors—sodium tungstate, ammonium molybdate, and zinc sulfate—were compared through seawater immersion experiments. Results indicated that zinc sulfate exhibited the highest corrosion inhibition efficiency for A3 carbon steel. A composite corrosion inhibitor was subsequently prepared by combining zinc sulfate with CMCS, and its performance was systematically investigated. The effects of inhibitor composition and dosage were evaluated using static full-immersion tests and the weight loss method. Optimal corrosion inhibition was achieved at a CMCS-to-zinc sulfate mass ratio of 1:2 with a total concentration of 200 mg/L, yielding an inhibition efficiency of 81.33%. This composite inhibitor demonstrated significantly superior performance compared to individual inhibitors.
  • Preparation of MOFs-GO Aerogel and its Adsorption Properties for Antibiotics
    LI Wei, XU Ziting, WANG He, LIU Shui, XIANG Tao
    Technology of Water Treatment. 2025, 6(7): 58-64.
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    To enhance the efficiency and stability of antibiotic adsorption by metal-organic frameworks (MOFs) in aqueous environments, a macroscopic MOF aerogel (UIO-66-NH₂/GO) was synthesized through a solvothermal process by combining UIO-66-NH₂ powder with graphene oxide (GO). The morphology, structure, and properties of UIO-66-NH₂/GO were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption experiments, and thermogravimetric analysis (TGA). Adsorption tests were then conducted to investigate the adsorption performance, mechanism, and reusability of UIO-66-NH₂/GO toward tetracycline and ciprofloxacin. The results confirmed that GO was successfully incorporated into UIO-66-NH₂, forming an octahedral spatial network. Under optimal conditions-12 hours of adsorption time at 40 °C, pH=7, and an initial antibiotic concentration of 40 mg/L-the maximum adsorption capacities for ciprofloxacin and tetracycline reached 144.32 mg/g and 158.25 mg/g, respectively. The adsorption of both antibiotics by UIO-66-NH₂/GO was found to be endothermic, spontaneous, and disordered, following the Langmuir isotherm and pseudo-second-order kinetics. After eight cycles of reuse, the antibiotic uptake capacity remained above 100 mg/g, demonstrating the UIO-66-NH₂/GO aerogel's robust reusability and regeneration potential.
  • Removal of Ciprofloxacin from Water by Activated PMS with Thermally Modified Fenton Sludge
    MI Huirong, YANG Xiaoman, DONG Xiya, QIN Huifang, HUANG Yingping, LI Ruiping
    Technology of Water Treatment. 2025, 6(7): 65-72.
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    Fenton sludge (FS) from a landfill leachate treatment plant was pyrolyzed at 300~700 °C under an N₂ atmosphere (denoted as FS-X, with X = 300, 400, 500, 600 and 700) and subsequently used to activate peroxymonosulfate (PMS) for the degradation of ciprofloxacin (CIP). The morphology and structure of FS-X were characterized by scanning electron microscopy, X-ray diffraction, and surface area analyses. The CIP removal efficiency of PMS activation was compared before and after sludge pyrolysis. Results indicated that FS-X had greater PMS activation capability than FS due to Fe3O4 as its main catalytic component, with FS-600 demonstrating the strongest CIP-removal performance. Specifically, in a system containing 0.5 g/L FS-600 and 1.5 mmol/L PMS, 99% of CIP (30 mg/L) was degraded within 120 minutes-significantly surpassing CIP adsorption by FS-600 alone (48.55%) and direct PMS oxidation (22.38%). Radical-trapping experiments and electron spin resonance analyses further revealed that singlet oxygen (1O2) and superoxide radicals (O2·- ) were the predominant active species in the FS-600/PMS process, rather than the conventional sulfate radicals (SO4·-) or hydroxyl radicals (·OH).
  • Preparation of PVDF/SMA Blend Membrane for Oil/Water Separation Via Lower Critical Solution Temperature Dope Solution System
    SI Xinyu, CHENG Zehuan, CHEN Yuchao, XIAO Tonghu
    Technology of Water Treatment. 2025, 6(7): 73-79.
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    Microfiltration (MF) membranes, characterized by controllable pore structures, have been widely utilized in oil/water emulsion separation processes due to their low energy consumption and other advantages. In this study, a casting solution system exhibiting a lower critical solution temperature (LCST) phenomenon was developed using polyvinylidene fluoride (PVDF) and styrene-maleic anhydride copolymer (SMA) as blended polymers, PVP and MgCl2 as additives, and N,N-dimethylacetamide (DMAc) as the solvent. The variation patterns of the LCST system were systematically investigated. Subsequently, PVDF/SMA blended membranes were prepared via the non-solvent thermally induced phase separation (NTIPS) method. The effects of SMA content and coagulation bath temperature on membrane structure, mechanical properties, and oil/water emulsion separation performance were explored. The results demonstrated that the membrane structure could be transformed from finger-like pores to bicontinuous porous structure by adjusting the coagulation bath temperature in the LCST casting solution system. When applied to oil/water emulsion separation, the PVDF/SMA blended membrane S-1.2 exhibited a retention rate of 99.7% for the oil/water emulsion. Compared to the pure PVDF membrane S-0 without SMA, the pure water flux recovery rate of the PVDF/SMA blended membrane S-1.2 increased from 82.5% to 88.3%. Additionally, the ratio of irreversible fouling resistance to the inherent resistance of the membrane decreased from 21.1% to 13.2%, indicating superior fouling resistance.
  • Effect of Polymeric Ferric Sulfate Flocculant on Biological Phosphorus Removal:Focusing on the Changes of Intracellular and Extracellular Polymerization
    XING Hong, WU Lihong, TIAN Tian, WANG Te
    Technology of Water Treatment. 2025, 6(7): 80-84.
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    To enhance biological phosphorus removal at low temperature (10~15 °C), the effect of polyferric sulfate (PFS) coagulant on the performance of an enhanced biological phosphorus-removal (EBPR) system was investigated and the underlying mechanisms were elucidated. Moderate PFS dosing improved the removal of chemical oxygen demand (COD) and soluble orthophosphate (SOP). At 200 mg/L PFS, effluent COD and SOP concentrations declined to 18 mg/L and 0.48 mg/L, corresponding to removal efficiencies of 92.1% and 94.5%, respectively. Excessive PFS, however, diminished EBPR performance. PFS addition improved sludge settleability and stimulated the secretion of extracellular polymeric substances (EPS), particularly proteins; EPS production increased with increasing PFS concentration. Regarding intracellular storage compounds, PFS enhanced the maximum accumulation of polyhydroxyalkanoates (PHA) to 6.84 mmol/g while reducing glycogen synthesis. The elevated PHA content intensified the metabolic activity of phosphorus-accumulating organisms, thereby improving biological phosphorus removal. These findings provide a theoretical basis for efficient, low-temperature treatment of phosphorus-laden wastewater using EBPR.
  • Mechanism and Efficiency of Contaminant Degradation in New Ferrihydrite/H2O2/Hydroxylamine
    WANG Kai, YU Huadong, WANG Ziyu, ZHANG Zhiqin, WU Liguang, LI Xuchun
    Technology of Water Treatment. 2025, 6(7): 85-89.
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    Fenton processes have been extensively applied in industrial wastewater, but still suffer from large formation of toxic sludge. In order to effectively reduce and utilize the Fenton sludge, this study proposed a new method using hydroxylamine (HA) to enhance the utilization of sludge in situ for contaminant degradation in heterogeneous Fenton processes. Using ferrihydrite (Fhy) as representative of Fenton sludge, this study investigated the kinetics of contaminant degradation, and examined the influence of typical factors including Fhy, H2O2, HA, pH, temperature. Increasing concentration of Fhy, HA, and H2O2 significantly enhanced the oxidation efficiency, and the fastest reaction kinetics were at pH 2.5~3 in the process. Elevating temperature promoted the reactions, with apparent activation energy of about 50.1 kJ/mol. The method can efficiently degrade pollutants in industrial wastewater using actual Fenton sludge. According to scavenging experiments and competitive reaction analysis, the reaction mechanism was revealed. Fe(II) was released from Fhy by attack of HA, and further participated in Fenton reactions to generate •OH, which accounted for the oxidation of contaminants. In addition, surface-attached •OHads also played a role in the process. This study would provide a strategy for reduction and utilization of Fenton sludge in industrial wastewater treatment.
  • Study on the Effect of Electrode Connection Modes on Electrocoagulation Defluoridation
    FENG Jianheng, CHEN Mingru, GUO Xu, ZHOU Binlong, ZHOU Lü
    Technology of Water Treatment. 2025, 6(7): 90-96.
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    More than 260 million people worldwide are affected by groundwater with high fluoride, and drinking high fluoride groundwater pose a threat to human health. Among the defluoridation methods, electrocoagulation has good defluoridation effect, easy control, and simple operation, making it suitable for defluoridation of drinking water in remote and dispersed areas. The electrode connection mode is an important influencing parameter of electrocoagulation. It is of great significance for the application of electrocoagulation defluoridation that the electrode connection mode with the best defluorination performance is proposed. This study compares the differences between three electrode connection modes, namely monopolar electrodes in parallel connection, monopolar electrodes in serial connection and bipolar electrodes in serial connection, from the perspective of the fluoride removal effectiveness and defluoridation process and mechanism, in order to improve the application possibility of electrocoagulation for defluoridation. The results indicate that when the initial fluorine concentration is 5 mg/L, the current density is 20 A/m2, and the electrode spacing is 15 mm, the fluorine concentration after electrocoagulation of the three electrode connection modes is less than 1.0 mg/L, which meets the drinking water standards of China. Compared with monopolar electrodes in parallel connection and bipolar electrodes in serial connection, monopolar electrodes in serial connection can reduce electro power consumption by 28%~38%, electrode consumption by 30%~47%, and floc volume by 35%~48%. Fluoride in electrocoagulation is removed by adsorption in aluminium hydroxide floc. The study shows that monopolar electrodes in serial connection is the best electrode connection mode.
  • Properties and Water Purification Efficacy of Alkali-Modified Balsam Wood Filler
    WANG Wenjin, ZHANG Jin, ZHANG Yuxin, HE Ling, XIE Xueyi
    Technology of Water Treatment. 2025, 6(7): 97-104.
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    Natural wood fiber tubes are widely used as porous biofilm carriers in wastewater treatment. However, removing lignin from these wood fiber bundles is often complicated and inefficient in practice. In this study, balsam fir was soaked in a dilute alkali solution and used as a filler to construct a water purification reactor targeting rural low C/N domestic wastewater, thereby investigating the effectiveness of alkali-modified balsam fir. The results indicated that: 1) a 17-day alkali treatment removed 39.39% of the lignin, while the cellulose and hemicellulose loss rates were 25.68% and 13.17%, respectively. The porosity of alkali-treated balsam fir reached 90.15%, which was 32.98% higher than that of untreated wood, and the strength loss was minimal (2.61%). 2) When employed as a reactor filler, alkali-modified balsam fir achieved COD, NH₃-N, TN, and TP removal rates of 92.86%, 75.80%, 67.07%, and 32.60%, respectively, when treating rural low C/N wastewater. 3) Scanning electron microscopy revealed increased pore size and dense microbial attachment on alkali-modified balsam fir. These findings demonstrate that using alkali-modified balsam fir as a biofilm carrier is cost-effective, requires straightforward pretreatment, and delivers superior treatment performance.
  • Performance Optimization and Regulation of Continuous Flow Anoxic MBBR-AAO Process System and Microbial Community Succession
    DENG Ao, ZHAO Ji, CHEN Qun, WANG Yuanyuan, YU Deshuang, WANG Xiaoxia
    Technology of Water Treatment. 2025, 6(7): 105-112.
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    This study evaluates the nitrogen and phosphorus removal efficiency of an anoxic moving bed biofilm reactor-anaerobic/anoxic/oxic (AM-AAO) process for urban wastewater treatment, by controlling influent C/N ratio, internal recycling ratio, hydraulic retention time (HRT), and temperature, were jointly optimized, alongside functional microbial community dynamics in activated sludge and biofilm. Operational parameters-including internal reflux ratio (250%), hydraulic retention time (HRT=7 h), sludge retention time (SRT=40 d), temperature (≈25 °C), and anoxic tank filling rate (30%)-were optimized over a 263 d period. Under stable conditions, the anaerobic tank exhibited excellent COD removal and phosphate release performance, with COD removal of 188.67 mg/L and phosphorus release (PO43--P) of 74.09 mg, supplying sufficient polyhydroxyalkanoates (PHAs) for subsequent phosphorus uptake. Exogenous denitrification and phosphorus removal predominantly occurred in the anoxic tank, yielding PO43--P uptake (PUAA=36.96 mg) and effluent NO3--N of 8.11 mg/L. The aerobic tank demonstrated robust nitrification (NH4⁺-N oxidation: 16.34 mg/L) and phosphorus absorption (PUAO=41.78 mg), with maximum NH4+-N removal efficiency of 98.57%. System-wide performance included total inorganic nitrogen (TIN) and COD removal rates of 83.08% and 86.16%, respectively, and final effluent concentrations of 6.64 mg/L NO3--N and 0.42 mg/L PO43--P. High-throughput sequencing revealed ammonia-oxidizing bacteria (AOB: Ellin6067, Nitrosomonas, 0.04%~0.12%) and nitrite-oxidizing bacteria (NOB: Nitrospira, 0.02%~0.04%) as key nitrification drivers. The glycogen-accumulating organisms (GAOs: Candidatus_Competibacter and Defluviicoccus, 3.49%~4.46%) dominated the endogenous denitrification process, while the polyphosphate-accumulating organisms (PAOs:Defluviimonas, Dechloromonas and Comamonadaceae, 3.79%~9.35%) ensured superior phosphorus removal performance.
  • Pilot Study on the Treatment of Surface Water with Varying Water Quality Using an Inclined tube reinforced circulating agglomerated granulation fluidized bed
    XUE Zhangzhe, HU Ruizhu, LI Kai, HUANG Tinglin
    Technology of Water Treatment. 2025, 6(7): 113-117.
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    To enhance the treatment efficiency of seasonal surface water with fluctuating quality, an inclined tube module was introduced to reinforce sedimentation at the fluidized bed outlet. A pilot study was conducted using this improved circulating fluidized bed, designed for pellet flocculation, to treat high- and low-turbidity as well as algae-rich raw water. Results indicate that, for influent turbidity ranging from 8~15 NTU (low) and 500~2 000 NTU (high), the fluidized bed effluent remained below 3 NTU under hydraulic loads of 28~70 m/h. In the inclined tube strengthening zone, turbidity was reduced even further, to less than 1.5 NTU. Meanwhile, CODMn and UV254 removal rates reached approximately (45±3.9)% and (50±2.3)% , respectively. Under conditions featuring an initial algal density of 20~27×10⁶ cells/L and a hydraulic rising load of 42 m/h, the enhanced process reduced algal density to 2.6~3.3×10⁶ cells/L, which was significantly better than conventional coagulation-sedimentation at 9 m/h. Owing to its high effluent quality, robust adaptability, and compact footprint, the inclined tube-reinforced circulating fluidized bed for pellet flocculation shows considerable promise for surface water treatment in rural and small-town environments with variable water quality.
  • Digital Assistance under the Background of "Dual Carbon" for the Optimization Strategy Research of the Existing Urban Sewage Treatment Plants
    CHEN Shilin, LI Cuimei, WANG Hao, JIN Guoyu, ZHOU Chao
    Technology of Water Treatment. 2025, 6(7): 118-124.
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    To optimize process parameters for urban sewage treatment under the "dual carbon" policy framework, this study developed a BioWin-based Bardenpho process model using a Suzhou wastewater treatment plant as a case study. The model was validated against historical operational data, and process parameters were optimized via the Box-Behnken response surface method. Interactive effects of operational parameters on effluent total nitrogen (TN) and total phosphorus (TP) concentrations were systematically analyzed. Results demonstrated steady-state and dynamic simulation errors maintained below 10%, confirming the model's accuracy in replicating real-world operations. Post-optimization, aerobic zone dissolved oxygen (DO) levels, internal recirculation ratio, and external recirculation ratio were maintained at 1.5~1.546 mg/L, 200%~214%, and 65%, respectively, achieving enhanced effluent quality. The strategy reduced aeration energy consumption by 16.2%, polyaluminum chloride (PAC) dosage by 15.5%, and carbon emissions by 400.14 kg CO₂/d. These findings provide actionable insights for optimizing biological nutrient removal efficiency while minimizing energy and chemical consumption in existing wastewater treatment plants.
  • Pilot Study on VFL-Ozone Catalytic Oxidation Process for Treatment of Landfill Leachate
    FAN Xueman, WANG Kun, LIU Chunxin, LI Qi
    Technology of Water Treatment. 2025, 6(7): 125-130.
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    This study investigated the treatment of mature landfill leachate via a VFL-ozone catalytic oxidation process. In the VFL biochemical system (COD/TN=2.3~3.0), average removal efficiencies were 72.7% for COD, 99.6% for ammonium nitrogen, and 97.9% for total nitrogen, resulting in effluent concentrations of 934 mg/L, 10.3 mg/L, and 51.6 mg/L, respectively. The ozone catalytic oxidation system (O3/COD=2) achieved a 91.1% average COD removal, yielding 80.4 mg/L of residual COD. The combined process consistently met the discharge requirements specified in Table 2 of GB 16889-2008, at an operational cost of 44.26 yuan/m³, without requiring membrane treatment. During seven months of operation, the VFL biochemical system maintained stable partial nitrification and denitrification (nitrite accumulation ratio >90%). High-throughput sequencing of activated sludge revealed that Nitrosomonas (2.09%) and Thauera (4.50%) were dominant among nitrifying and denitrifying bacteria, thereby underpinning the stable partial nitrification-denitrification. Quantitative analyses of nitrogen-related functional genes and metabolic pathways further clarified nitrogen metabolism in the VFL system.
  • Study on Effect of Microbubble Ozonation on Activated Sludge Floc Particles
    LIU Chun, LIANG Xiaolei, ZHANG Jing, LIU Lin, XU Junjie
    Technology of Water Treatment. 2025, 6(7): 131-136.
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    In this study, microbubble ozonation (O₃/MB) was applied to activated sludge flocs to assess its effects on particle structure and removal efficiency. The strong oxidative action and flotation from O₃/MB disrupted the sludge floc matrix and aided in separating floc particles from the liquid phase. After 60 min of treatment, the mixed liquor suspended solids (MLSS) removal efficiency reached 95.1%. The median particle size (D50) decreased from 150 µm to 17 µm, and the sludge particle density rose by a factor of 6.66, indicating near-complete floc breakdown. Surface examinations revealed porous etching and disintegration, accompanied by reduced intensities of functional groups related to polysaccharides, proteins, and aromatic structures. Simultaneously, the sludge zeta potential increased from -31.78 mV to -27.58 mV, reflecting a diminished negative surface charge, and the sludge moisture content also declined. During O₃/MB treatment, organic compounds such as extracellular polymeric substances (EPS) were released into the supernatant and subsequently degraded. As a result, concentrations of soluble chemical oxygen demand (SCOD), proteins (PN), and polysaccharides (PS) in the supernatant first rose and then diminished with time, while the oxidative degradation of organic nitrogen elevated the ammonia nitrogen concentration.
  • Performance and Fouling Characteristics of the New Quality Zero-Carbon Membrane Technology in Rural Drinking Water Treatment
    JIANG Lijie, WU Yaqin, HUANG Minmin, PAN Weijun, ZHONG Yinghong, WU Sifan
    Technology of Water Treatment. 2025, 6(7): 137-142.
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    A zero-carbon membrane technology featuring near-zero energy demand, no chemical consumption and minimal maintenance was developed to overcome the high water use, complex cleaning and maintenance requirements of conventional rural drinking-water membrane systems. The technology was installed at a single-village supply station in Zhejiang Province and operated in direct-filtration mode to treat rainstorm-induced, high-turbidity raw water. Purification efficiency, flux stability and fouling behaviour were monitored for almost six months of continuous operation without backwashing. The system consistently produced permeate with turbidity <0.2 NTU and SDI15<5, while partially retaining dissolved organic matter (e.g., proteins) together with Fe and Mn. At operating fluxes ≤12 L/(m2·h) the permeate flux remained stable and specific flux loss was negligible. Fouling diagnosis showed that reversible inorganic scaling was the dominant foulant and could be removed by simple hydraulic rinsing. The process required only 0.007 kWh/m³, consumed <2% of the treated water for self-operation and generated no chemical-cleaning effluent, demonstrating clear economic and environmental advantages over conventional membrane technologies. These results underpin the wider deployment of zero-carbon membranes in decentralised drinking-water supplies.
  • Design of Upgrading and Renovation Project for Leachate Treatment Station of a Waste Landfill in Guizhou
    ZHU Haidong, FU Dafang, SINGH Rajendra Prasad
    Technology of Water Treatment. 2025, 6(7): 143-147.
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    To address the low organic strength and pronounced quality fluctuations of leachate from a mid-stage municipal solid-waste landfill in Guizhou, the existing treatment plant was retrofitted with a "pre-treatment + external-side membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO)" process train. Constraints imposed by a compressed schedule, limited budget, restricted footprint and rugged terrain were mitigated through a compact plant layout, replacement of cast-in-situ concrete basins with steel tanks, and deployment of modular, containerised membrane units. After the upgrade, the hydraulic capacity reached 300 m3/d and the effluent consistently complied with the discharge limits in Table 3 of the Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889–2008). During 3.5 years of operation, the MBR achieved mean removal efficiencies of 91.2%±0.1% for chemical oxygen demand (COD) and 99.1%±0.03% for ammonium-nitrogen (NH4+-N). The NF stage removed a further 83.7%±0.5% of residual COD, whereas the RO unit yielded overall removals of 83.1%±0.3% for COD and 78.5%±1.1% for NH₄⁺-N. Capital expenditure was approximately 16.5 million CNY and the operating cost averaged 36.07 CNY/m3, demonstrating favourable economics and scalability. This case study provides a practical reference for upgrading landfill-leachate treatment facilities under similar constraints.
  • An Application Example of Rural Domestic Sewage Treatment Project with Microbial Immobilization and AAOA Combined Process
    RAN Yunlong, GUO Lei, CHEN Shoukai, LI Xin, LI Guanghui
    Technology of Water Treatment. 2025, 6(7): 148-151.
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    The rural domestic sewage treatment system of 100m³/d scale based on Microbial Immobilization and AAOA Combined Process was constructed and applied in a village in Xinxiang City.Henan Province.The technological process, design parameters and operation effect of the project were introduced in detail.The practice showed that this process had a good treatment effect on COD, NH3-N, TP and TNwithin semester of operation., and the average removal rates were86.05%, 98.46%, 92.33% and 64.99% respectively. The average mass concentration of effluent was reduced to 16.01.0.30, 0.10, and 9.08 mg/L respectively.The effluent quality index was better than the first level A criteria specified in the GB 18918-2002.The equipment has strong ability to resist shock load, stable effect operation and low running cost, which can provide references for the technical selection and operation of rural domestic sewage treatment.
  • Application Research of Electro Oxidation Process in the Treatment of High Salt and Ammonia Containing Wastewater
    SHI Guozhong, XU Haoran, YAN Yilei, FENG Xiangdong, YAO Zhikan, ZHANG Lin
    Technology of Water Treatment. 2025, 6(7): 152-156.
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    After years of treatment, most of the conventional wastewater from coal-fired power plants has been reasonably reused, but there are still deficiencies in the adcanced treatment of high-salt ammonia containing wastewater. The ammonia containing wastewater from coal-fired power plants has the characteristics of large water volume, high ammonia content, and high salt content, which far exceeds the ammonia nitrogen limit of 15 mg/L in the national sewage discharge standard, and it is difficult to achieve reuse standards through simple treatment. Based on the water quality characteristics and treatment requirements of ammonia containing wastewater from coal-fired power plants, an electrochemical oxidation ammonia containing wastewater treatment project with 2×60 m3/h treatment capacity was designed and constructed, and the system operation strategy was developed. The results indicate that the system can meet the demand of 209 000 tons/year of ammonia containing wastewater in coal-fired power plants, and use the residual chlorine as a disinfectant for the cooling water system. The effluent ammonia nitrogen concentration is less than 1 mg/L through influent quality conditioning and reactor current control, and the effluent pH value is not less than 6.0 through influent pH control and ammonia nitrogen concentration control. Increasing the reactor current is beneficial for improving the efficiency of ammonia nitrogen removal and residual chlorine concentration in the effluent, but it will affect the system energy consumption and effluent pH value. The static investment of the project is 7.09 million yuan, the operating economic cost is 1.825 million yuan/year, the static investment recovery period is 4.7 years, and the removal of ammonia nitrogen pollutants is 14 630 kg/year. Compared with the original breakpoint chlorination process, it has the advantages of high energy efficiency, small equipment footprint, no need to add chemicals, low operating costs, and no secondary pollution, providing engineering experience for the green and efficient treatment of similar ammonia containing wastewater.
Administrated:
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Chief Editor：
Gao Congjie (Academician of Chinese Academy of Engineering)
Editor in Chief：Wang Qi
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