10 December 2025, Volume 51 Issue 12
    

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  • Research Progress on Inactivating Pathogenic Microorganisms in Water by Ultraviolet-Peroxyorganic Acid Technology
    LI Wei, XU Ziting, DONG Zijun, WANG Feng, FANG Jingyun, SUN Shichang
    Technology of Water Treatment. 2025, 51(12): 1-9.
    Abstract | Download PDF URL | Cite this Article Knowledge map Save
    As an emerging water treatment technology, Ultraviolet peroxyorganic acid (UV-POA) enhances treatment efficiency by more than twice compared to UV disinfection technology or peroxide organic acid technology alone through the synergistic effect of photochemistry and free radical oxidation. This article systematically explains the reaction characteristics of peroxyorganic acids in water treatment by oxidizing pathogenic microbial cell membranes and nucleic acids to inactivate them. It analyzes the multi active species disinfection mechanism and inactivation principle of UV-POA technology, which mainly contributes to oxidation by directly destroying nucleic acid bound hydroxyl radicals with ultraviolet radiation, and has stronger adaptability to complex water quality such as high organic matter and high turbidity. Compared with chlorine disinfection technology, its by-products are mainly low toxicity carboxylic acids, without the generation of mutagenic chlorine containing by-products, significantly reducing health risks. Summarized and compared the differences between UV/POA technology and chlorine disinfection technology in the direction of inactivating microbial pollutants in water, and proposed the advantages and application prospects of UV/POA technology in high efficiency, broad-spectrum, environmental friendliness, and anti-interference. This provides theoretical support for the systematic analysis of UV/POA disinfection mechanism in China, and provides reference for the theoretical innovation and engineering practice of UV/POA technology in the field of water safety.
  • Application of Artificial Neural Networks in Anaerobic Digestion: Progress and Prospects for Biogas Production Modeling and Optimization
    SUN Ruilin, WANG Zhe, ZHAI Chenghui
    Technology of Water Treatment. 2025, 51(12): 10-17.
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    Anaerobic digestion (AD) is a key technology for organic waste treatment and renewable energy recovery. However, its practical application is often hindered by challenges such as low biogas production efficiency and process instability, making modeling and optimization particularly critical. In recent years, machine learning approaches—especially artificial neural networks (ANN)—have exhibited notable advantages in modeling and parameter optimization for AD processes. By classifying ANN models based on their structural functions, this study systematically reviews their applications in biogas production prediction, multi-objective optimization, and process monitoring, with a specific focus on evaluating the performance of hybrid neural network optimization models. Results indicate that the prediction accuracy (R2) of ANN and its extended hybrid models typically exceeds 0.97. Nevertheless, notable limitations persist, including heavy reliance on high-quality monitoring data, substantial computational resource consumption, and insufficient model interpretability. Future research should prioritize the integration of real-time monitoring technologies with intelligent modeling methods to facilitate the industrial application of these models, thereby providing robust support for the efficient and stable operation of AD systems.
  • Research Progress on Quantitative Detection of Reactive Oxygen Species in the Persulfate-Based Fenton-Like Systems
    WANG Xin, MA Jianqing, ZHANG Huining, JIN Huixia, ZHANG Kefeng
    Technology of Water Treatment. 2025, 51(12): 18-24.
    Abstract | Download PDF URL | Cite this Article Knowledge map Save
    Advanced oxidation technologies, especially persulfate-based Fenton-like reactions, have attracted significant attention owing to their broad pH adaptability and robust resistance to interference from impurities. Quantitative detection of reactive oxygen species (ROS) is essential for elucidating reaction mechanisms and optimizing processes; however, conventional techniques exhibit notable limitations and controversies. This review systematically evaluates ROS quantification methods in persulfate systems, including chemical probe reaction kinetics, electron paramagnetic resonance (EPR), chemiluminescence, and electrochemical techniques, while analyzing their principles, advantages, and limitations to guide method selection. Future research should prioritize the development of highly specific probes, simplified instrumentation for cost reduction, and enhanced accuracy. Additionally, advancing real-time and in situ detection technologies will facilitate the broader application of advanced oxidation processes in wastewater treatment.
  • Research Progress on Numerical Simulation of Air Gap Membrane Distillation
    DU Yongliang, XIE Shibei, YUAN Hongying, BI Haojie, XU Zhiyuan, LI Mengkai
    Technology of Water Treatment. 2025, 51(12): 25-33.
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    Membrane distillation is increasingly deployed for seawater desalination; within this field, air-gap membrane distillation (AGMD) has gained prominence because of its superior thermal efficiency. In the context of global carbon-neutrality goals, the energy-saving potential of AGMD is especially attractive. Numerical modelling has become an indispensable tool for elucidating coupled mass- and heat-transfer mechanisms in AGMD and for improving module design. This review summarises recent numerical investigations with respect to module configurations, transport models, computational approaches and practical applications. Particular attention is given to studies that address concentration and temperature polarisation, process-parameter optimisation and structural optimisation of membrane modules.
  • Progress on Microwave Activated Persulfate for Degradation of PPCPs in Water
    PAN Jieyi, LIN Qintie, LIU Yuxin, ZHAO Zirui, WEI Longyi, HUANG Jianwen
    Technology of Water Treatment. 2025, 51(12): 34-40.
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    Pharmaceutical and personal care products (PPCPs) are a new category of pollutants that have received widespread attention in recent years. High concentrations of PPCPs have been detected in the inlet and outlet water and sludge of the sewage treatment plant, posing a threat to the environment and human health. It is difficult to remove PPCPs effectively by traditional water treatment processes, and microwave-activated persulfate is an efficiency water treatment technology in recent years. In this paper, the reaction mechanism and application progress of persulfates activated by single microwave, microwave-reinforced carbon-based materials, microwave-reinforced metal-based materials and microwave-reinforced composites for the degradation of PPCPs are reviewed. The advantages and disadvantages of different activators are described, and the development direction of microwave-activated persulfate is prospected. The aim is to provide a reference for the application of microwave-activated persulfate for the degradation of PPCPs.
  • Research Progress On Wastewater Treatment by Constructed Wetland Coupled Microbial Fuel Cell (CW-MFC) Technology
    WEI Wei, HAN Caiyun, LU Yuanda, LIN Weiqiang, LIANG Liying, MU Chunxia
    Technology of Water Treatment. 2025, 51(12): 41-48.
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    Constructed wetland microbial fuel cell technology (CW-MFC) is a new type of water treatment technology coupled with constructed wetland (CW) and microbial fuel cell technology (MFC). It uses microorganisms to decompose organic matter in wastewater to generate electrical energy. While generating electricity, it can improve the water treatment effect of CW, and has low cost and no secondary pollution. It has broad application prospects and important research value. This paper introduces the CW-MFC process, and summarizes the research status of CW-MFC technology in the treatment of heavy metal wastewater, organic wastewater, salt-containing wastewater and phenol-containing wastewater, and looks forward to its future development direction, in order to provide reference for the development and application of this technology in the treatment of various types of wastewater.
  • Recovery of Iron-phosphate from a Supernatant of Waste Activated Sludge by Electrolysis pH Enhance Anaerobic Fermentation
    CHEN Tengshu, YU Wanjun, SONG Xingfu
    Technology of Water Treatment. 2025, 51(12): 49-53.
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    Waste activated sludge (WAS) is rich in phosphorus (P) and therefore constitutes an important secondary P resource. Efficient recovery of this phosphorus remains a research priority. Vivianite (Fe3(PO4)2·8H2O) crystallisation has emerged as a promising route, offering substantial economic and environmental benefits. In this study, pH adjustment was used to enhance P release from WAS into the supernatant, after which liquid- and solid-phase P fractions were characterised to clarify the contribution of solid P to overall release. The supernatant was subsequently subjected to electrochemical recrystallisation, yielding vivianite with an overall P-recovery efficiency of 97% and a product purity of 77.339%.
  • Study on the Depassivation Process and Application of Pre-Oxidized Modified Zero-Valent Iron
    SONG Ludi, WU Chao, PAN Yiyu, ZHANG Yanping, WU Yaqin, ZHU Haitao, ZHANG Lin
    Technology of Water Treatment. 2025, 51(12): 54-59.
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    Pre-oxidized microscale zero-valent iron (poZVIbm) was synthesized by ball milling iron powder with peroxydisulfate (PDS) solids. Physicochemical characterization revealed that this pre-oxidation method preserved the α-Fe crystal structure of zero-valent iron while generating a substantial amount of Fe(II) in situ on the material surface. These surface Fe(II) sites facilitated a continuous, self-driven depassivation process, during which the Fe(0) core in poZVIbm declined from 59.5% to 9.3% within two hours of contact with water, alongside a gradual decrease in bulk-solution pH. Molecular dynamics simulations indicate that poZVIbm's surface groups, exhibiting a low acidity constant (pKas=3.16), create a localized acidic microenvironment that underpins this self-driven depassivation. In practical applications, poZVIbm demonstrated excellent performance in treating textile dyeing wastewater: the BOD5/CODCr ratio rose from 0.047 to 0.305, underscoring poZVIbm's potential as a functional reagent for wastewater remediation.
  • Study on the Preparation of SPDA@MIL-101 Modified Polyethersulfone Ultrafiltration Membranes and the Mitigation of Membrane Fouling
    HAO Xiujuan, LI Yukun, YAO Meng, JU Zheng, HU Yukai
    Technology of Water Treatment. 2025, 51(12): 60-65.
    Abstract | Download PDF URL | Cite this Article Knowledge map Save
    To address the fouling of ultrafiltration membranes by extracellular organic matter during high-algae water treatment, a novel sulfonated polydopamine (SPDA)-functionalized metal-organic framework (SPDA@MIL-101) was synthesized. This SPDA@MIL-101 nanocomposite was then incorporated into a polyethersulfone (PES) matrix via blending modification. The modified membrane was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurements, zeta potential analysis, and porosity tests. At an SPDA@MIL-101 addition level of 0.1 wt%, the modified membrane exhibited optimal comprehensive performance, with a pure water flux of 540 L/(m2·h) and a UV254 rejection rate of 30%. After three fouling filtration cycles, the flux recovery ratio (FRR) increased to 89%, while the irreversible fouling ratio was reduced to 11%. Compared with the unmodified membrane, the pure water flux was 1.88 times higher, the UV254 rejection rate was 16% higher, and the flux recovery ratio was 17% higher. These results lay a solid foundation for the widespread application of ultrafiltration membranes in high-algae water treatment.
  • Study on the High-Efficiency Activation of Persulfate by MoS2 and FeMoO4 for the Tetracycline Degradation
    BAI Yiwei, HE Zhengguang, FAN Xiangge, JIA Yuxin, LIANG Ke
    Technology of Water Treatment. 2025, 51(12): 66-71.
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    The FeMoO4@MoS2 composite was synthesized via a two-step hydrothermal method and evaluated for tetracycline (TC) degradation through peroxymonosulfate (PMS) activation. Structural characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) confirmed the successful formation of a lamellar MoS2 coating on microspherical FeMoO4, with homogeneous distribution of Fe, Mo, S, and O. Systematic investigations of operational parameters—including TC concentration (20 mg/L), catalyst dosage (0.20 g/L), PMS concentration (0.6 mmol/L), and initial pH (6.46) —achieved a 96.8% TC degradation efficiency. Radical quenching experiments identified singlet oxygen (1O2) and superoxide radicals (·O2-) as the dominant reactive species, with minor contributions from sulfate (SO4·-) and hydroxyl (·OH) radicals. The enhanced catalytic performance of FeMoO4 through MoS2 loading demonstrates a promising strategy for pharmaceutical and personal care product (PPCP) remediation.
  • Adsorption and Removal of As(III) by Biochar Loaded with Ferromanganese Oxides
    DENG Ying, DENG Zhuoyin, WANG Siyi, QIU Jing, HU Ruiyue, GUO Jing
    Technology of Water Treatment. 2025, 51(12): 72-80.
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    This study evaluated the capacity of biochar-supported iron-manganese oxides synthesised by an optimised impregnation method (FMBC) and of their lanthanum-doped analogue prepared by co-precipitation (FMLa@BC) for removing As(III) from water. Material morphology and surface chemistry were characterised by SEM, XRD, XPS and FTIR. Batch adsorption tests examined the influence of pH (3~9) and co-existing ions; kinetic and equilibrium data were fitted with common models to clarify the adsorption mechanism. For both adsorbents the kinetics obeyed the pseudo-second-order model and the isotherms conformed to the Langmuir equation, indicating monolayer chemisorption. Under neutral conditions the maximum capacities reached 62.9 mg/g (FMBC) and 61.0 mg/g (FMLa@BC). Competing anions had little effect on performance, and lanthanum doping increased the density of surface -OH groups, generating additional binding sites for As(III). Optimised FMBC and, in particular, La-doped FMLa@BC are cost-effective and robust adsorbents for arsenic remediation in aqueous systems.
  • Treatment of Simulated Acid Orange 7 Wastewater Based on UV-Fenton Reaction Catalyzed by Natural Iron-Containing Minerals
    PENG Huiling, LAI Faying, WANG Guofeng, XIONG Jiaping, LAI Rongsheng, HE Jinbao
    Technology of Water Treatment. 2025, 51(12): 81-87.
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    The efficiency and mechanism of treating acid orange 7 (AO7) azo dye by UV-Fenton system with iron-containing minerals were studied using natural pyrite, magnetite, ilmenite, vanadium titanium magnetite, magnesioferrite and iron tourmaline as catalysts. The results showed that the introduction of UV significantly improved the degradation efficiency of acid orange 7 using the Fenton system catalyzed by six minerals. The optimal TOC removal rates for magnetite and magnesioferrite were 58.06% and 56.64%, respectively, and the treatment effects of these systems were significantly correlated with the contents of total dissolved iron ions. By comparing with the homogeneous UV-Fenton system with equal contents of dissolved iron ions, it was found that the oxidation treatment effect of UV-Fenton system catalyzed by these minerals mainly came from the homogeneous UV-Fenton oxidation catalyzed by dissolved iron ions, while the contribution from UV-Fenton oxidation catalyzed by the surface of minerals was not significant. In addition, it was showed that UV direct photolysis and photo assisted decomposition of H2O2 had weak oxidation effect, while the photocatalytic oxidation from pyrite, magnetite and magnesioferrite after first or second use had a certain contribution to the degradation of AO7. Meanwhile, the surface dissolution process of pyrite, iron tourmaline and vanadium titanium magnetite had a significant impact on the treatment effect of the system. Magnetite and magnesioferrite exhibit stable and efficient catalytic performance, low iron leaching capacity, certain photocatalytic oxidation activity, and are convenient for magnetic recovery, which are the potential catalysts for heterogeneous UV-Fenton system.
  • Study on the Degradation of Tetracycline by EDTA Enhanced Fe2+/PMS System
    YANG Hui, CAO Heyang, WANG Jianhua, WANG Shiyu
    Technology of Water Treatment. 2025, 51(12): 88-93.
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    To further enhance the activation effect of Fe2+ on peroxymonosulfate (PMS), an EDTA enhanced Fe2+ activated PMS (Fe2+/PMS) system was developed for the degradation of tetracycline. The study investigated the effects of four different reaction conditions—Fe2+/EDTA molar ratio, initial pH, PMS dosage, and tetracycline initial concentration—on the degradation efficiency of tetracycline, utilizing response surface analysis to determine the optimal reaction conditions. The results indicated that when the dosage of Fe²⁺ was 0.10 mmol/L, the Fe2+/EDTA molar ratio was 7.7:1, the initial pH was 5.19, the PMS dosage was 0.70 mmol/L, and the tetracycline concentration was 10 mg/L, the degradation rate of tetracycline reached as high as 95.59%. Chemical quenching experiments and EPR detection confirmed that SO4•- playing a major role in the degradation process. Furthermore, the degradation of tetracycline in the system followed a second-order reaction kinetics model.
  • Feasibility Study on UV/Hydrogen Peroxide Combined with Biochemical Treatment for DMF Wastewater
    JIANG Ling, LIU Zehao, WANG Hui, ZHANG Liang
    Technology of Water Treatment. 2025, 51(12): 94-98.
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    By optimizing the ultraviolet/hydrogen peroxide (UV/H2O2) process conditions, efficient treatment of wastewater containing N, N-dimethylformamide (DMF) was achieved,and the degradation pathway of DMF was inferred. Additionally,the impact of the treated wastewater on biological activity was investigated, and the potential of a combined treatment process was proposed and envisioned. During the process optimization phase,simulated DMF wastewater (DMF concentration of 800 mg/L) was used to investigate the effects of initial pH values (1, 2, 3, 4, 5, 6) and H2O2 dosages(0, 3.7, 6.8, 20.5, 34.2 mg/L)on the degradation of DMF by the UV/H2O2 process. The experimental results showed that when the initial pH value was 4 and the H2O2 dosage was 20.5 mg/L,the removal efficiency of DMF, chemical oxygen demand (COD) and total organic carbon (TOC) were 99.7%, 91.3% and 90.9%,respectively. After UV/H2O2 treatment,part of the nitrogen in DMF was released in the form of ammonia nitrogen, and the system achieved a total nitrogen removal efficiency of 54.4%. Through gas chromatography-mass spectrometry (GC-MS) analysis, combined with natural product analysis (NPA), charge distribution analysis and frontier electron density, the degradation pathway and products of DMF were predicted. After pretreatment of wastewater, the short-term inhibition of microbial activity can be reduced,and more than 50% dilution of the treated wastewater can eliminate the short-term inhibition of microbial activity, which is suitable for the start-up ratio of bioreactor.
  • A novel Process Simulation for Water-Cooling Cogeneration Process of Ammonia Refrigeration Driven by Low-Temperature Heat
    ZHANG Shuaishuai, CHENG Yaqi, LIU Yuanbo, ZHENG Tong, RUAN Da, MA Xuehu
    Technology of Water Treatment. 2025, 51(12): 99-107.
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    The wet desulfurization of flue gas contains a lot of water vapor, which causes waste of water resources and "white plume". Aiming at the problem that the wet flue gas heat transfer efficiency is low and the cooling medium temperature limits the water recovery efficiency. A new process of water-cooling cogeneration process of ammonia refrigeration driven by low-temperature heat. The dual-effect ammonia absorption refrigeration system driven by the step utilization of low-grade flue gas waste heat provides to supply the two-stage water collection unit. The process simulation software Aspen-plus is used to simulate the whole process. The simulation results show that the temperature of the wet air is reduced to 15 ℃, the water vapor content is reduced to less than 1.7% which achieves a water recovery rate of up to 77%, under the joint action of the two-stage water recovery device. The new process realizes step utilization of flue gas waste heat, water recovery and cooling capacity production. And it can provide a cooling capacity of 14.7 MW around -10 °C. It can save 2.25×106 m3 of industrial water and 1.06×108 kW·h of industrial electricity every year which has good economic and social benefits.
  • Performance of Microalgae and Aerobic Granular Sludge Combined System for Nitrogen Removal From Inorganic Wastewater
    ZENG Lingcong, LUO Yi, WANG Liujia, CHENG Yuanyuan, LIU Liliang, LONG Bei
    Technology of Water Treatment. 2025, 51(12): 108-112.
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    A microalgae-aerobic granular sludge (AGS) combined denitrification system was constructed to provide technical reference for efficient denitrification of ionic rare earth mine tailwater. Microalgae and AGS stored in the laboratory were inoculated to initiate the primary microalgae reactor and the secondary AGS reactor, respectively, and the two reactors were operated in series. After 30 days of operation, the chlorophyll a concentration and algal density of the microalgae were 16.11 mg/L and 1007 mg/L, respectively. The AGS structure became more compact, with an SVI of 33.93 mg/L and a granulation rate of 96.04%.The effluent quality of the microalgae system stabilized from the 25th day onward, removing approximately 40% of ammonia nitrogen and 30% of total inorganic nitrogen (TIN) from the influent. The AGS system's effluent stabilized from the 15th day, achieving 90% NH4+-N removal and 57% TIN removal from the primary effluent.The steady-state contribution rates of NH4+-N and TIN removal in the primary microalgae system were 39.80%~44.90% and 44.29%~54.17%, respectively, while those in the secondary AGS system were 55.10%~60.20% and 46.48%~54.17%, respectively. The combined microalgae-AGS system achieved steady-state removal efficiencies of approximately 95% for NH4+-N and 70% for TIN, with the final effluent meeting the discharge limits specified in Water Pollutant Discharge Standards for Mining of Ion-absorbed Rare Earth Ores (DB 36/1016–2018).
  • Fabrication of High-Performance Nanofiltration Membranes Based on Alkali Etching Enhancement and Its Application to the Purification of Micro-Polluted Surface Water
    CAI Shengyun, GUO Ruixia, QIAN Junwei, ZHU Xuewu
    Technology of Water Treatment. 2025, 51(12): 113-119.
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    Polyamide (PA) nanofiltration (NF) membranes exhibit significant potential for water treatment applications owing to their high permeability, selectivity, and inherent antifouling properties. However, the trade-off between permeability and selectivity remains the core challenge in current PA NF membrane fabrication. In this study, a strategy for preparing high-performance NF membranes was developed via interfacial polymerization (IP) combined with optimized thermal treatment and post-treatment processes. Systematic investigations revealed that using NaOH as a thermal treatment reagent can etch into the PA active layer and promote the hydrolysis of acyl chloride groups. This process yields NF membranes with enhanced negative surface charge, improved hydrophilicity, and increased pore size. The optimized NF-3 membrane demonstrated outstanding performance, achieving a water flux of 24.3 L/(m2·h·bar) and a Na2SO4 rejection rate of 96.9%. The NF-3 membrane also exhibited excellent selectivity for both monovalent and multivalent ions. Moreover, in the purification of natural surface water, the NF-3 membrane effectively removed organic contaminants while retaining essential minerals, thereby enabling the production of safe drinking water with a well-balanced mineral composition. This research provides a valuable reference for the practical application of nanofiltration processes in water treatment systems and the design of high-performance NF membranes.
  • Research on Fenton-TCCA Combined Process for Deep Treatment of Landfill Leachate
    LUO Jingjing, DENG Haitao, LUO Jun, WU Lieshan, LIU Dan, LYU Qianfeng
    Technology of Water Treatment. 2025, 51(12): 120-124.
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    Landfill leachate is a complex, highly organic wastewater that is difficult to treat. Although the leachate from a Guangxi landfill undergoes biological treatment, its chemical oxygen demand (COD) remains elevated. This study therefore proposes an advanced oxidation system that couples Fenton chemistry with trichloro­isocyanuric acid (TCCA) and benchmarks its performance against a conventional two-stage Fenton process. The effects of TCCA dosage and initial pH on COD removal were systematically investigated to determine optimal operating conditions. At pH 7.0 and a TCCA dosage of 7 g/L, the hybrid Fenton-TCCA process achieved a COD removal efficiency of 96.94%, significantly surpassing the two-stage Fenton treatment.
  • The Operational Performance of the AAO Process for Treating Rural Wastewater from Low-Carbon Sources During Winter
    WEI Jiaoteng, WANG Nan, BAI Shaoyuan, WANG Mei, ZHONG Yijian
    Technology of Water Treatment. 2025, 51(12): 125-131.
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    As of 2022, the rural wastewater treatment rate in China was only approximately 31%, resulting in significant regional gaps. Rural domestic wastewater, characterized by low carbon source content, presents substantial challenges for treatment technologies. Using the anaerobic-anoxic-oxic (AAO) process to treat actual rural domestic wastewater in winter, this study investigated system operational performance, optimized parameters, and analyzed microbial communities under anaerobic, anoxic, and aerobic conditions. The results showed that when treating low-carbon-source rural domestic wastewater in winter, the AAO process exhibited significant sludge loss, secondary phosphorus release, and nitrification inhibition; the dominant genus was Zoogloea (13.87%~15.05%), which produces large amounts of extracellular polymeric substances (EPS). At an food-to-microorganism (F/M) ratio of 0.173 ± 0.029 kgCOD/(kgMLSS·d), overgrowth of Thiothrix (7.01%~11.51%) led to sludge bulking. An F/M ratio of 0.225±0.023 kgCOD/(kgMLSS·d) maintained an efficient activated sludge system, with average removal efficiencies of 95.19% for COD, 91.09% for TP, 83.53% for TN, and 98.09% for NH4+-N. This study discusses sludge stability, nitrogen and phosphorus removal efficiencies, and shifts in functional microorganisms of the AAO process under different operating conditions for rural domestic wastewater treatment, which can aid in enhancing rural water environment treatment efficiency and improving the human habitat.
  • Optimization of Process Parameters for High-Density Slurry Method (HDS) for Acidic Mine Wastewater Treatment by Pilot-Scale and Semi-Pilot-Scale Sequential Experimentation
    JIA Tongfu, ZHANG Xinyan, LI Pansheng, CHI YuLei, TANG Liyun, ZHONG Weijun
    Technology of Water Treatment. 2025, 51(12): 132-138.
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    The generation of acidic mine wastewater (AMW) is frequently accompanied by heavy metal contamination, which elevates the complexity and cost of wastewater treatment. To improve the treatment efficiency of the conventional high-density slurry method for AMW, this study employed a two-stage neutralization-oxidation-flocculation-sedimentation process integrated with the high-density slurry method for AMW treatment. Through combined bench-scale and pilot-scale sequential experiments, the optimal process parameters of the system were identified, and the key mechanism underlying the synergistic removal of heavy metals via neutralization reactions and transformation was elucidated. Key parameters include hydraulic retention time (HRT), calcium oxide (CaO) dosage, and sludge return flow rate. Experimental optimization results indicate that the system's efficient operating conditions are as follows: primary reaction tank pH=8.5~8.9; CaO dosage = 3.0~3.4 kg/m3 of wastewater; air-to-water ratio=(3~6):1; HRT = 0.8~1 h; flocculant polyacrylamide (PAM) dosage=15~20 g/m3 of wastewater; sludge concentration=20%; and sludge return ratio = 14%~19%. A significant synergistic effect was observed in the removal of total iron (TFe) and zinc (Zn). Iron (Fe) and manganese (Mn) are primarily removed via oxidation and co-precipitation with neutralization products and flocculants. This research provides important theoretical and technical support for the design, commissioning, construction, and cost-effective operation of full-scale AMW treatment processes.
  • Effect of Hydraulic Residence Time on Synergistic Methanogenic Performance of Photosynthetic Bacteria and Methanogenic Archaea And Its Mechanism
    GUO Yulin, ZHUANG Minghan, LI Ningjie, WANG Shuhui
    Technology of Water Treatment. 2025, 51(12): 139-144.
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    In a bio-hybrid photomethanogenic system, the cyanobacterium Synechocystis sp. PCC 6803 replaced conventional semiconductor photocatalysts to drive methane formation in co-culture with Methanosarcina barkeri. Light-dark cycles, coupled with Fe(III)/Fe(II) redox cycling, supported simultaneous symbiotic growth and methane production. The consortium was operated in a continuous-flow reactor at hydraulic retention times (HRTs) of 6, 9 and 12 h; the HRT of 12 h yielded the highest methane output (2.47±0.17 µmol per cycle). Quantitative PCR showed 6.97- and 1.26-fold increases in cpcG and mcrA copy numbers, respectively, confirming mutualistic proliferation of the phototroph and methanogen. The medium exhibited high electrical conductivity and a low redox potential, consistent with the accumulation of conductive extracellular polymeric substances that stabilised electron transfer. Partial least-squares path modelling indicated that HRT positively influenced biomass (path coefficient = 0.43), whereas biomass strongly promoted methane production (0.92), demonstrating that retention time modulates methane output indirectly through microbial growth.
  • The Upgrading and Process Optimisation of A Wastewater Treatment Plant (Phase I) in Dalian City
    ZHANG Yuxin, FAN Zhongxiang, LIU Changyuan, ZHOU Ziyu, WU Yinghai
    Technology of Water Treatment. 2025, 51(12): 145-149.
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    A wastewater treatment plant in Dalian, which completed Phase I construction, underwent upgrading to meet stricter effluent quality standards. Originally, the plant employed the Cyclic Activated Sludge Technology (CAST) process, achieving Class 1B effluent per the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB 18918–2002). To comply with national environmental protection regulations, the effluent standard was upgraded to Class 1A. With a treatment capacity of 35 000 m3/d, the upgraded system now employs the treatment process: "aerated grit removal→modified AA/O (anaerobic-anoxic-oxic)→coagulation (sedimentation stage)→filtration→UV disinfection". The original biochemical tanks were modified; new grid flocculation tanks and V-shaped filter tanks were constructed; and the existing sludge treatment system was upgraded. The upgraded plant now stably achieves Class 1A effluent quality. This study provides a reference for similar upgrading projects.
  • A Case Study of Treatment of Steroid Hormone Wastewater by Combination of Physicochemical and Biochemical Processes
    TANG Chaoqun, YANG Xiaoling, WANG Baiyang, HUANG Donggen, YUAN Haosheng
    Technology of Water Treatment. 2025, 51(12): 150-155.
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    A biopharmaceutical enterprise specializing in steroid hormone production generates large volumes of wastewater during its manufacturing processes. This wastewater is characterized by high salinity, high chemical oxygen demand (COD), high ammonia nitrogen concentrations, and low biodegradability. Additionally, this wastewater contains relatively high concentrations of dimethylformamide (DMF), as well as trace amounts of pyridine and other characteristic pollutants. The effluent from the enterprise's original wastewater treatment process did not meet regulatory discharge standards. To address the unique water quality characteristics of steroid hormone wastewater, the initial treatment process was modified to adopt an integrated process comprising iron-carbon Fenton pretreatment, hydrolytic acidification, anaerobic digestion, anoxic/oxic (A/O) process, biological contact oxidation, and dissolved air flotation (DAF). Operational results show that this integrated process effectively treats steroid hormone wastewater, achieving a COD removal rate of 98% and an ammonia nitrogen removal rate of 90%, while consistently meeting the discharge standards for industrial park sewage treatment plants.
Administrated:
China National BlueStar (Group) Co., Ltd
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Gao Congjie (Academician of Chinese Academy of Engineering)
Editor in Chief：Wang Qi
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