10 April 2025, Volume 51 Issue 4
    

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  • HE Junxia, ZHOU Jingzhou, XIA Siqing
    Technology of Water Treatment. 2025, 51(4): 1-7.
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    Halogenated organic pollutants (HOPs), prevalent in aquatic environments, pose critical threats to ecological security and human health because of their persistence, bioaccumulation, and toxicity. Consequently, developing new strategies for effective HOP removal is of paramount importance. The hydrogen-based membrane biofilm reactor (H2-MBfR), which integrates bubble-free aeration via hollow-fiber membranes with hydrogenotrophic reduction, has attracted substantial attention for its cost-effectiveness, minimal intermediate toxicity, and ability to remove multiple contaminants simultaneously. Reflecting these advantages, research on H2-MBfR's role in HOP degradation has expanded considerably. This paper reviews laboratory findings on H2-MBfR applications for eliminating HOPs, systematically assessing its degradation efficiency across various pollutants and examining the principal factors influencing removal. It also elucidates the mechanisms and dominant microorganisms involved, and briefly discusses challenges alongside possible solutions. These insights provide theoretical guidance and reference points for both the engineering implementation and broader adoption of H₂-MBfR technology.
  • YIN Xinxing, YUAN Zhengban, GAO Ruiying, ZHANG Ying
    Technology of Water Treatment. 2025, 51(4): 8-13.
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    With the growth of the global population and economic development, the demand for freshwater continues to rise. Although large-scale membrane desalination is energy-intensive, an appropriate pretreatment process can reduce seawater impurities and dissolved substances, thereby ensuring efficient desalination, extending membrane service life, and lowering overall energy consumption. Drawing on recent domestic and international case studies of large-scale membrane desalination plants, this work examines how key water quality indicators affect membrane desalination, while comparing and analyzing the performance of various common pretreatment processes from multiple perspectives. Based on these findings, specific pretreatment recommendations are provided for different water quality conditions. According to the results, when the turbidity is below 0.1 NTU, SDI15<2, and year-round TOC<1 mg/L, only reverse osmosis security filters are needed. For seawater with turbidity under 30 NTU and year-round TOC<4 mg/L, a single-stage filtration process is recommended. If turbidity is below 50 NTU, SDI15> 5, and TOC ≥4 mg/L, a sedimentation-plus-single-stage filtration process is more suitable. Finally, when turbidity exceeds 50 NTU, SDI15>5, and TOC≥ 4 mg/L, a high-speed sedimentation-plus-two-stage filtration process is advised. These recommendations provide a valuable reference for the design and application of large-scale seawater desalination pretreatment processes.
  • ZHANG Xinyi, WEN Jinlong, HU Yuying
    Technology of Water Treatment. 2025, 51(4): 14-21.
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    Bisphenol A (BPA) is a typical endocrine disruptor with toxicity, which poses a serious threat to water environment safety and human health, and its molecular structure is very stable, which is difficult to remove by conventional treatment methods. Therefore, the development of efficient and economical BPA wastewater treatment technology has become the focus of researchers. The advanced oxidation technology of heterogeneous catalytic activated persulfate can effectively degrade BPA in water, which has the advantages of mild reaction conditions and easy recovery of catalyst. In this paper, the progress of transition metals, carbon materials and coupling methods in activated persulfate degradation of BPA was reviewed, and the free radical and non-free radical mechanisms of heterogeneous catalytic activated persulfate degradation of BPA were analyzed in detail. The effects of pH, persulfate concentration, activator concentration, inorganic anions, cations and organic matter in water matrix on the degradation of BPA were also discussed.
  • JIN Yabin, XU Tiantian, ZHOU Liang, WAN Zhengjie, ZHANG Gaoming
    Technology of Water Treatment. 2025, 51(4): 22-28.
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    Photocatalytic technologies offer considerable promise for the remediation of industrial wastewater, characterized by their superior efficiency, operational convenience, and versatile adaptability. This manuscript undertakes an exhaustive examination of recent studies concerning the abatement of harmful pollutants in industrial effluents via the utilization of vanadate composite materials alongside photocatalytic degradation methodologies. Commencing with an elucidation of the myriad synthesis techniques for vanadate composites-including hydrothermal, sol-gel, atomic layer deposition, and physical vapor deposition methods-the discourse progresses to dissect the employment and underlying mechanisms of metal oxide/vanadate, g-C3N4/vanadate, and metal-doped vanadate composite catalysts in the attenuation of pollutants. Through a methodical appraisal and synthesis of existing research, this inquiry further delineates the prospective evolutionary trajectories and the potential challenges vanadate composites might confront within the ambit of industrial wastewater treatment.
  • LIANG Ruike, YAN Song, GUO Danhui, WU Zhourui, XU Rui, ZHANG Yong
    Technology of Water Treatment. 2025, 51(4): 29-34.
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    Pollution is generally present in agricultural production and people's life, and its pollution types are wide. But no matter what type of agricultural and rural pollution, it always involves water pollution. So, the control of agricultural and rural water pollution is one of the important measures to promote the green and low-carbon development of agriculture and rural areas, strengthen the construction of rural ecological civilization and protect people's health. As an in-situ bioremediation technology for treating water pollution, ecological floating beds are widely used because of their advantages of simplicity, high efficiency, low energy consumption and low cost. This paper takes the concept, history and development of eco-floating bed technology as an entry point, introduces the latest progress of eco-floating bed's main structure and reinforcement technology, and enumerates the application scenarios of eco-floating bed technology in agricultural and rural wastewater treatment, and finally looks forward to the prospects of the application of eco-floating bed technology in the development of low-carbon eco-agricultural rural construction, so as to provide scientific references for the realization of the win-win situation between rural ecological restoration and economic and social benefits.
  • LU Xiuguo, JIE Shan, FU Yuling
    Technology of Water Treatment. 2025, 51(4): 35-41.
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    The magnetically modified walnut shell-based biochar INBC was prepared by chemical co-precipitation by carrying Fe3O4 magnetic particles using walnut shell as raw material, and it was used to adsorb erythromycin in water. A series of characterization methods, such as SEM, XRD, FT-IR and VSM, were used to analyze the morphology and structure of INBC, and the effects of single factor variables such as INBC dosage, initial pH, initial concentration, and temperature on the adsorption efficiency of erythromycin in water were discussed. The results showed that when the initial concentration of erythromycin was 20 mg/L, the dosage of INBC was 0.3 g/L, the initial pH value was controlled at 7, and the optimal removal rate of 98.04% and the adsorption capacity of 65.39 mg/g could be obtained at a constant temperature of 35 °C for 240 min at a rotation speed of 200 r/min.
  • WANG Qun, XIONG Renxuan, ZHANG Yu, LI Sitong, XIAO Yang
    Technology of Water Treatment. 2025, 51(4): 42-46.
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    Using Cuprous oxide(Cu2O) as catalyst, the degradation of Methylene blue(MB) in water by activated periodate (PI) was studied.The effects of PI initial concentration, Cu2O dosage, initial pH and anions on MB degradation efficiency of Cu2O/PI were studied. Under the optimum conditions, the total degradation rate of MB was 93.6% when pH= 6, initial concentration of MB was 20 μmol/L, reacted with 1.0 g/L Cu2O and 0.5 mmol/L PI for 40 min.By fitting pseudo-first-order kinetics of the reaction, the degradation of MB was divided into two stages, the cut-off point was t = 10 min. Cu2O/PI system had good tolerance to NO3- and SO42-, but high Cl- content inhibited the degradation of MB, and CO32- had significant inhibitory effect on the degradation of MB, which increased with the increase of concentration. The properties of Cu2O were characterized by FTIR, XRD and XPS.The free radical capture experiments showed that the active species in the Cu2O/PI system were ∙OH, O2- and 1O2, and the main active species were 1O2,O2- followed by, and dissolved oxygen also has a certain role in promoting.The XPS results showed that Cu (II) was produced in the Cu2O/PI system, and the oxidation-reduction of Cu played an important role in the formation of 1O2. The catalyst cycle experiment for 5 times showed that Cu2O was stable.
  • LIU Shuang, YUAN Ye, ZHOU Jia, ZHAO Shuai, ZHAO Leizhen, QU Jianhang
    Technology of Water Treatment. 2025, 51(4): 47-52.
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    This study aimed to screen the efficient aerobic denitrifying phosphorus-accumulating bacterium, explore its nitrogen metabolism pathway, optimize the nitrogen and phosphorus removal conditions, and provide some references for its application in the wastewater nitrogen and phosphorus removal treatment.By dilution coating method based on the BTB identification medium, the efficient denitrifying phosphorus-accumulating bacterium was isolated and screened from the activated sludge of a wastewater treatment plant. The taxonomic classification of the isolate was identified by the morphological observation and phylogenetic analysis of 16S rRNA genes. The nitrogen removal pathway was explored by detection of the intermediate metabolites and analysis of the nitrogen balance. The optimal nitrogen and phosphorus removal conditions were investigated by single factor experiment. Results showed that the highly effective denitrifying phosphorus-accumulating strain D8 was isolated and identified as Aeromonas sp., and the removal rates of PO43--P, NO3--N and NH4+-N by strain D8 were 100%, 92.24% and 87.20%, respectively; Strain D8 had three complex nitrogen metabolic pathways including ammonia assimilation, nitrate reduction and heterotrophic nitrification-aerobic denitrification. The optimal nitrogen and phosphorus removal conditions were NaAc as carbon source, C/N of 9, pH 7.0~9.0 and temperature of 28 ℃.
  • DING Jieran, ZHANG Hongyu, HAN Zhibo, CHENG Ying, LIANG Yajie, LI Fengxin
    Technology of Water Treatment. 2025, 51(4): 53-58.
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    Fe₃O₄ was synthesized using a hydrothermal method and combined with an acetylene black-PTFE electrode (ABP) to form an electro-Fenton system for activating persulfate (PS) to degrade metronidazole in water. The effectiveness of the electro-Fenton coupled persulfate system in degrading metronidazole was demonstrated. Results indicated that Fe3O4 enhanced metronidazole degradation, but excessive dosing did not improve the degradation efficiency. Acidic conditions favored metronidazole degradation, and the degradation rate was highest when the PS dosage was 3 mmol. Temperature exhibited a positive correlation with metronidazole degradation. Under optimal conditions, the ABP/Fe3O4/PS system achieved a metronidazole removal rate of 91.1%. The contribution order of active radicals in the reaction system was SO4·->·OH>O2·-. The primary reason for the improved degradation rate compared to a single advanced oxidation system is the enhanced generation of SO4·- due to the coupling effect, which increases PS activation efficiency.
  • ZHOU Xizheng, HE Bin, LIANG Xiaochun, LI Lanqing, CHENG Jiang Yongchao, ZHANG Li
    Technology of Water Treatment. 2025, 51(4): 59-63.
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    This study proposes a microwave-enhanced humidification and dehumidification desalination system due to its flexible scale and low capital investment. To investigate the effects of power, vacuum pressure, and initial water temperature on pure water yield, an experiment was conducted using three power levels (0.96 kW, 0.81 kW, 0.63 kW), four vacuum pressure levels (0 kPa,-10 kPa, -20 kPa, -30 kPa), and seven temperature levels (40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃). A single-factor control method was employed. Results indicate that pure water output increases with higher power, stronger vacuum, and elevated initial water temperature. Energy efficiency improves with increasing vacuum pressure and power, yet it exhibits no significant change with varying initial water temperature. The gained output ratio (GOR) rises with increasing power, initial water temperature, and vacuum pressure, whereas the specific thermal energy consumption (STEC) decreases under the same conditions. The highest water yield, greatest energy efficiency, maximum GOR, and lowest STEC were all observed under a power of 0.96 kW, an initial water temperature of 70 ℃, and a vacuum pressure of -30 kPa.
  • XU Wendi, CHEN Yuting, HE Xi, ZHANG Dong, YANG Mingfei, CAI Yuanxin
    Technology of Water Treatment. 2025, 51(4): 64-69.
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    Nickel ferrite (NiFe2O4) was synthesized by the sol-gel method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. The NiFe O was then used to activate sodium persulfate for Rhodamine B degradation. Single-factor tests identified the optimal conditions as follows: 1.5 g/L sodium persulfate, 20 mg/L Rhodamine B, pH 7 (unadjusted), and 1 g/L NiFe2O4. Under these conditions, RhB degradation reached 90.23% within 120 min. Moreover, the introduction of an external light source into the advanced oxidation system significantly reduced the degradation time. With photoassistance, RhB degradation reached 89.64% in just 20 min, nearly 100 min faster than without photoactivation, and achieved 98.92% within 50 min. A comparison of the reaction rates with and without illumination revealed a pronounced enhancement of the catalytic oxidation rate in the presence of light.
  • LUO Zuyun, LIU Xinyue, ZHANG Jiabing, CAI Yuqing, LÜ Yangen
    Technology of Water Treatment. 2025, 51(4): 70-76.
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    The layered porous structure of three-dimensional (3D) graphene aerogel imparts a high specific surface area and pronounced porosity, thereby enhancing both adsorption efficiency and photocatalytic degradation of pollutants and rendering it a promising candidate for water purification. In this study, polypyrrole/graphene aerogel composites containing varying amounts of pyrrole were prepared via hydrothermal reduction coupled with freeze-drying. Their adsorption and photocatalytic performance against malachite green and hexavalent chromium (Cr(VI)) was investigated, revealing removal efficiencies exceeding 91%. These three-dimensional polypyrrole/graphene aerogel composites thus exhibit strong adsorption and photocatalytic capabilities, offering valuable insights into improving the removal of pollutants and heavy metal ions from contaminated wastewater.
  • MENG Duo, CHU Shuping, SHAO Wei, LIU Wei
    Technology of Water Treatment. 2025, 51(4): 77-84.
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    In order to achieve efficient removal of methylene blue from water, Box-Behnken response surface method was used to optimize the preparation of pinecone shell-sludge biochar material. The interaction effects of three factors, including pyrolysis temperature, addition amount of pinecone shell and pyrolysis time, on the adsorption properties of pinecone shell-sludge biochar were investigated, and the optimal preparation conditions were determined. Elemental analyzer, BET, FTIR and other methods were used to characterize the composition, pore structure and functional group types of sludge biochar, and explore the influencing factors and adsorption mechanism of sludgy-pine shell biochar on methylene blue adsorption properties. The results showed that the pyrolysis temperature was the most significant factor affecting the adsorption performance of pinecone shell-sludge biochar. The optimum conditions for the preparation of pinecone shell-sludge biochar were pyrolysis temperature of 800 ℃, addition of 20wt% pinecone shell and pyrolysis time of 4 h. The specific surface area, total pore volume and average pore diameter of biochar increased with the addition of pinecone shell, which was conducive to the improvement of adsorption capacity. The optimal adsorption conditions were determined as initial pH=9, initial concentration of methylene blue 20 mg/L, dosage of pinecone hull-sludge biochar 60 mg, and reaction time 120 min. The adsorption removal rate of methylene blue was 96.85%. The adsorption process of methylene blue by pinecone husk-sludge biochar conforms to the quasi-second-order kinetic model. The limiting step of adsorption rate is chemisorption, and the adsorption rate of MB is controlled by intra granular diffusion and membrane diffusion. Langmuir and Temkin isothermal adsorption models can describe the MB adsorption process well, which is mainly monolayer adsorption and electrostatic interaction.
  • MA Jiale, ZHOU Pengfei, CHEN Dihao, YAN Xianghui
    Technology of Water Treatment. 2025, 51(4): 85-91.
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    A series of Fe-N-C materials (denoted as APD/oAPF/Fx-Fe1.5-HT2) were synthesized by hydrothermal method combined with pyrolysis and alkali etching, using silane coupling agent, triblock copolymer F127 and o-aminophenol as the main precursors. The synthesis-structure-performance relationships between the average molecular weight of F127, structural properties of the obtained Fe-N-C materials and their performances in electrocatalytic cathodic oxygen reduction reaction (ORR) and degradation of Rhodamine B (Rh B) in electro-Fenton (EF) system were studied. The results indicated that with the increase of average molecular weight of F127, the phase and carbon structure of the as-prepared Fe-N-C microspheres hardly changed, but their dispersion and particle size generally became higher and smaller, respectively, and both the surface nitrogen content and specific surface area showed a trend of first increase and then decrease. The Fe-N-C material (APD/oAPF/F2-Fe1.5-HT2) prepared from F127 with a medium average molecular weight (Mn~2900) had the better sphericity, higher degree of graphitization, highest nitrogen content and specific surface area, extremely low content of crystalline iron species as well. Accordingly, the APD/oAPF/F2-Fe1.5-HT2 catalyzed ORR in a four-electron pathway and exhibited comparable activity to that of commercial Pt/C catalyst. The above series Fe-N-C microspheres as a cathode could also effectively degrade Rh B in EF system, especially the degradation percentage of Rh B on the APD/oAPF/F2-Fe1.5-HT2 reached 92.7% in 90 minutes. Moreover, a good cyclic stability was observed.
  • XIAO Fei, YANG Zihai, WANG Shimin, ZHAO Fengde
    Technology of Water Treatment. 2025, 51(4): 92-98.
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    The mature salt-tolerant aerobic granular sludge will disintegrate during long-term operation, so it is of great value for future engineering applications to freeze and store and regenerate the salt-tolerant aerobic granular sludge. A dual stirring sequencing batch reactor (SBR) with a high aspect ratio (RH/D) of 3.6 was utilized to preserve the frozen salt-tolerant aerobic granular sludge for 80 days. The study aimed to assess the impact of varying stirring rate gradients on the sludge's physical and chemical properties, its pollutant degradation capabilities, and its resilience to COD loading post-regeneration. The findings indicated that after 60 days, the average particle size of the sludge reached approximately 1 087.4 μm, with MLSS and SVI30 values stabilizing around 5.43 g/L and 36 mL/g, respectively. The sludge exhibited a high biomass concentration and superior settling characteristics. The average removal efficiencies for COD, NH4 +-N, and TP were 81.67%, 78.27%, and 70.19%, correspondingly. When the COD concentration surpassed 1 800 mg/L, the microorganisms on the sludge's surface transitioned from rod-shaped to spherical forms, and the regenerated sludge particles demonstrated a maximum COD loading tolerance of 3 000 mg/L. The optimal operational parameters, as determined by response surface optimization, were a COD loading of 2 010.5 mg/L and a stirring rate of 126.8 r/min. Under these experimental conditions, the simulated removal rates for NH4 +-N and TP were 90.93% and 88.33%, respectively. The operational strategy of freezing storage and regeneration offers valuable insights for the sustainable operation of salt-tolerant aerobic granular sludge.
  • CUI Yan, LUO Zhang, FENG Yunjie, CHEN Shenqiang, CHAI Xiaoxin, HU Pan
    Technology of Water Treatment. 2025, 51(4): 99-104.
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    To investigate the removal performance of polysilicate metal salts (PSiMs) on microplastics (MPs) in water, polyaluminum silicate sulfate (PSiAl), polytitanium silicate sulfate (PSiTi), and polyferric silicate sulfate (PSiFe) were prepared to remove 0.1~5.0 μm polystyrene (PS) microplastics. Results revealed that both PSiTi and PSiAl achieved an MP removal efficiency exceeding 80%, significantly outperforming PSiFe. Moreover, PSiTi required a lower optimal dosage than PSiAl, owing to the high charge neutralization efficiency of Ti⁴⁺ and the strong binding affinity between Ti⁴⁺ and MPs. The primary coagulation mechanism of PSiMs involves charge neutralization and complexation between the metal ions and MPs, along with a three-dimensional network structure that promotes both adsorption bridging and net sweeping. In addition, further experiments confirmed that PSiTi and PSiAl effectively removed 500 nm polymethyl methacrylate, polyvinyl chloride, and PS microplastics in three different real-world water samples. These findings hold significant research and practical value for ensuring water safety and human health through MP removal using PSiMs.
  • WANG Guanghui, LI Chen, LIU Qiang, LI Ying, LI Yuxuan, LI Xinran
    Technology of Water Treatment. 2025, 51(4): 105-112.
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    The combination process of "upflow lightweight ceramisite biofilter + (polyaluminum chloride) coagulation + lateral flow plated desilter + upflow ultralightweight-medium filter + (sodium hypochlorite) disinfection" was adopted to treat with the raw water from Yudai river, which is the only source of Yunlong lake. Effluent COD, BOD5, NH4+-N, TP, fecal coliform align with the Environmental Quality Standards for Surface Water (GB3838-2002), class I, I, II, II, and I standards, averaged TN removal is 50.55%, and effluent TN is above class IV. Although the effluent TN is high, due to the extremely low concentrations of COD, BOD5, NH4+-N and TP, the nutrient balance necessary for algae growth is destroyed, and the algae in Yunlong Lake can be effectively controlled .
  • MA HaiBo, MIAO LiYong, XIAO Bo, JIANG XiaoYu, RONG Yi, REN WuAng
    Technology of Water Treatment. 2025, 51(4): 113-117.
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    Given the characteristics of decentralized domestic wastewater, sucn as high organic content, intricate composition, and significant water volume fluctuations, this study suggests employing a sequential AAO and SBR process for wastewater treatment. The results show that the average concentration of COD, NH4+-N and TN in the effluent of the combined process are 22.9, 2.82 and 7.6 mg/L, respectively, meeting the primary A discharge standard of GB18918-2002. Additionally, the average TP concentration is 0.832 mg/L and to comply with the primary A discharge standard, the chemical phosphorus removal process is incorporated at the end of the combined process, achieving a TP reduction to 0.416 mg/L with a PAC dosage of 10 mg/L, thereby meeting the discharge requirements. Simultaneously, under two operational conditions of intermittent water intake and continuous water intake, the combined process achieves a removal rate of over 90% for COD, NH4+-N and TN, meeting the primary A discharge standard. These findings demonstrate the effectiveness of the combined process in wastewater treatment and its capability to handle influent shock loads, positioning it as an ideal technology for decentralized domestic wastewater treatment.
  • CAO Rong, GENG Anchao, GENG Ce, SHAN Yiting, LI Xu
    Technology of Water Treatment. 2025, 51(4): 118-122.
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    In this study, a combined biological powdered activated carbon/non-submerged ultrafiltration (BPAC/NSUF) process was used to treat slightly polluted raw water. The unique cross-flow design of the NSUF unit significantly enhanced the overall treatment efficiency, maintaining an effluent turbidity below 0.1 NTU and achieving a turbidity removal rate of over 95%. Under stable operation, the average removal rates for ammonia nitrogen and the permanganate index (CODMn) were 77.6%. In addition, the transmembrane pressure difference and membrane flux varied more gradually, and physical cleaning after each operational cycle restored both by more than 90%. Finally, the effects of physical cleaning duration and chemical reagent choice on membrane flux recovery were explored, and chemically enhanced physical cleaning further improved the cleaning efficiency, achieving up to a 100% recovery rate.
  • YUAN Yidan, LI Kelin, LI Jiaxuan, QIN XuanLin, WU Zijian, HUANG Zhongliang
    Technology of Water Treatment. 2025, 51(4): 123-129.
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    In this research, a tiered artificial wetland system centered around a tertiary plant pond was employed to treat agricultural irrigation water. The main objectives were to evaluate its effectiveness in removing conventional pollutants and antibiotics, as well as to investigate seasonal variations and their effects. This study also examined the structural characteristics of rhizospheric soil bacterial communities within the wetland units. Results showed that the artificial wetland achieved high pollutant removal efficiencies, with annual average removal rates of 61.31% for chemical oxygen demand (COD), 59.30% for total phosphorus (TP), 59.21% for total nitrogen (TN), and 61.34% for nitrate nitrogen (NO3--N). Notably, the emergent plant unit (C1) displayed superior COD removal, while the submersed-floating plant unit (C3) was more effective at removing nitrogen and phosphorus. In addition, the system demonstrated strong antibiotic removal capacity for tetracyclines (TCs), β-lactams (β-Ls), fluoroquinolones (FQs), macrolides (MLs), and sulfonamides (SAs), with rates reaching 100% for TCs and FQs. The dominant phyla and genera in the rhizospheric bacterial communities were similar across the wetland units, although their relative abundances differed, reflecting diverse pollutant removal functions for denitrification, phosphorus removal, and organic matter degradation. Overall, this study provides valuable insights into the application of artificial wetlands for mitigating conventional pollutants and antibiotics in agricultural irrigation water.
  • TONG Min, LI Hongqiang
    Technology of Water Treatment. 2025, 51(4): 130-135.
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    An A/O-MABR system was established to treat coking wastewater under conditions of high ammonia nitrogen in the influent and varying ambient temperatures, with an analysis of the microbial community structure of the system. With influent ammonia nitrogen concentrations ranging from 250 to 350 mg/L, the system demonstrated robust resistance to ammonia nitrogen shock loading, achieving average effluent concentrations of 2.85 mg/L for ammonia nitrogen and 319.69 mg/L for COD. At 40 °C, the A/O-MABR system exhibited optimal pollutant removal efficiency, with average removal rates of 97.3% for ammonia nitrogen and 79.5% for COD. Microbial analysis revealed that Proteobacteria and Chloroflexi were the dominant bacterial phyla in both the anoxic and aerobic zones under varying ambient temperatures. The MABR biofilm was enriched with functional microbial groups, such as Nitrospirota and Acidobacteriota, which enhanced the system's carbon and nitrogen removal performance.
  • HU Tengyu, GE Pinging, YANG Xiaolin, XU Xinpei, LI Baoan, TIAN Hailong
    Technology of Water Treatment. 2025, 51(4): 136-140.
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    Toluene, a typical carcinogenic organic compound, severely harms the environment. In this study, two highly efficient toluene-degrading bacteria (HTZ1 and HTZ2) were isolated and then introduced in different sequences into aerated membranes to form synthetic biofilms. Under an influent toluene concentration of 800 mg/L and a hydraulic retention time (HRT) of 12 hours, toluene removal rates reached 97.6 ± 0.3% (HTZ1-HTZ2) and 96.2±0.4% (HTZ2-HTZ1). High-throughput 16S rDNA sequencing revealed that the initially inoculated strain ultimately dominated the biofilm community, with HTZ1 experiencing less impact from inoculation order than HTZ2. Non-target metabolomics analysis indicated that key metabolic pathways enhancing microbial toluene degradation—such as the tricarboxylic acid (TCA) cycle, γ-aminobutyric-acid synapses, two-component systems, and ABC transport—were significantly up-regulated in 1#MABR biofilm compared with 2#MABR biofilm (p< 0.05), potentially explaining the observed discrepancy in toluene removal between the two reactors. These results also demonstrate that the sequence in which strains are introduced can strongly influence the performance of synthetic biofilms in membrane aerated biofilm reactors (MABRs). In conclusion, effective toluene removal was achieved in the MABR through synthetic biofilms, and the underlying ecological mechanism was preliminarily elucidated, offering an important reference for the broader application of MABRs in the efficient treatment of toxic benzene pollutants.
  • YANG Chenyu, QU Xuan, LI Weiwei, HAO Xiaogang, LI Huifang, ZHANG Rong
    Technology of Water Treatment. 2025, 51(4): 141-147.
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    The removal of emulsified oil in coal pyrolysis wastewater by carbon dioxide flotation was carried out in a bench reactor. The influences of flotation time, carbon dioxide flow rate, reaction pressure, and temperature on the pH value of wastewater and the removal of emulsified oil were investigated, and the interaction among the factors was revealed using response surface methodology. Furthermore, a prediction model for emulsified oil removal was established. The results show that the pH value of wastewater stabilize for several minutes and then decrease during carbon dioxide flotation. The pH value of decreases from 8.64 to near 7.10. The removal of emulsified oil is closely related to the pH value of wastewater and the properties of bubbles. In the temperature range of 40~70 ℃, the decreasing order of significance for maximization of emulsified oil removal is as follows: flotation time, carbon dioxide flow rate and reaction pressure. The interaction between flotation time and carbon dioxide flow rate is the most significant. The optimized parameters obtained from response surface analysis are carbon dioxide flow rate of 58.5 mL/min, reaction pressure of 0.4 MPa, and flotation time of 25 min. The removal of emulsified oil is 83.19% under the optimized parameters, with a deviation of only 0.07% from the predicted value.
  • DONG Mingfu, ZHANG Lin, CHEN Chunmei, ZHAO Maojie, YU Bo
    Technology of Water Treatment. 2025, 51(4): 148-152.
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    To address complex water quality changes and strictly adhere to the Class A discharge standard, the town's wastewater treatment plant has implemented an AO biochemical process combined with integrated MBR membrane treatment for process retrofitting. Water quality analysis identified the challenge as the removal of unusually high concentrations of total nitrogen, ammonia nitrogen, and total phosphorus without additional land use. To improve influent water quality, a basket grille was installed at the inlet to handle large solid waste. The existing regulating tank and sludge drying pond were merged and deepened, with the addition of an anoxic tank and aerobic tank. The dosing system was optimized, and the points for chemical addition were adjusted. Regular maintenance of the MBR membrane was standardized, enhancing treatment efficiency. Data tracking over nearly six months has shown stable Class A standard compliance in the effluent. The retrofit system significantly improved the removal efficiency of total nitrogen (93%), ammonia nitrogen (96%), and total phosphorus (95%), ensuring wastewater treatment in the town and protecting the receiving water body and downstream water safety.
  • HUA Lei, TANG Huyu, ZHU Yufang, JIANG Jianhong, LI Yingjie, ZOU Aiyi
    Technology of Water Treatment. 2025, 51(4): 153-156.
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    The wastewater discharged by four enterprises in an industrial park contains heavy metal ions, leading to elevated heavy metal content in the sludge of the sewage treatment plant. This transforms the sludge into hazardous solid waste and increases disposal costs. To address this issue, a centralized heavy metal wastewater treatment station was established in the park. The station treats the combined heavy metal wastewater from the four enterprises using a process comprising pretreatment, chemical precipitation, electrocoagulation, and filtration. The treated wastewater meets the heavy metal ion concentration limits specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants (GB 18918-2002). The effluent is then discharged into the centralized sewage treatment plant for further treatment, as outlined in Tables 2 and 3.