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  Current Issue
 
2024 Vol.44 Issue.7,Published 2024-07-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Microbiology
Environmental Ecology
Carbon Emission Control
Emerging Contaminants
Ecology Toxicology
Beautilful China Initiative: Environmental Economy
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2024 Vol. 44 (7): 0-0 [Abstract] ( 97 ) [HTML 1KB] [ PDF 262KB] ( 730 )
Air Pollution Control
3553 Characteristics of light absorption, sources, and radiative effects of brown carbon aerosol in Chongqing during winter based on on-line measurement: Implications of secondary formation
DENG Jing-cheng, PENG Chao, LU Pei-li, LI Zhen-liang, CHEN Yang, ZHAI Chong-zhi, YANG Fu-mo, TIAN Mi
To investigate the light absorption characteristics and environmental effects of brown carbon (BrC) during pollution and clean periods, the light absorption coefficients of BrC were obtained by Aethalometer (AE33) from 20th January 2023 to 21st February 2023 in Chongqing. The results showed that the AAE values of PM2.5 were 1.58 and 1.55 during pollution and clean periods, implying the presence of BrC in urban PM2.5. During the campaign, BC and BrC contributed 58%~90% and 10%~42% to PM2.5 absorption at 370~660 nm, indicating σ_abs was mainly affected by BC, but the contribution of BrC can not be ignored. The light absorption coefficient of BrC at 370 nm [σ_BrC(370)] was (35.30±8.21) Mm-1 during pollution periods, 2.47 times higher than that during clean periods [(14.28±7.10) Mm-1], and its contribution to σ_abs (10%~42%) was higher than those during clean periods (8%~41%). It is worth noting that the AAEBrC values during pollution periods ranged from 3.2 to 4.7, generally lower than those during clean periods (3.6~4.9), which might be related to the difference of BrC components during the different periods. The light absorption coefficients of primary brown carbon (BrCpri) and secondary brown carbon (BrCsec) were obtained based on the minimum R squired method (MRS). The contributions of BrCpri to σ_BrC were 74%~80% and 57%~74% during pollution and clean periods, higher than that of BrCsec (20%~26% and 26%~43%). However, The AAE values of BrCpri during pollution and clean periods were 3.42 and 3.08, significantly lower than the corresponding AAE(BrCsec) (4.22 and 5.15), which was related to the strong wavelength dependence of BrCsec light absorption. In addition, the daily variation of σ_BrCsec(370) suggested that BrCsec production might be mainly affected by the liquid-phase reaction under high humidity conditions at night. The radiative absorption contribution of BrC relative to BC was more significant in short wavelengths and decreased obviously with increasing wavelengths. The radiative absorption contributions of BrCpri and BrCsec at 370~950 nm were 24.8% and 10.2% during pollution periods, higher than that during clean periods (18.4% and 9.8%), respectively. The results of the potential source contribution function (PSCF) showed that the local emissions were the main sources of BrC during pollution periods in Chongqing, while regional transport from Hunan province and Guizhou province had major impacts of BrC during clean periods.
2024 Vol. 44 (7): 3553-3562 [Abstract] ( 183 ) [HTML 1KB] [ PDF 1677KB] ( 934 )
3563 Changes and causes of CO2 concentration in Hangzhou during COVID-19
CHEN Xiao-ming, LIU Shuo, ZANG Kun-peng, LIN Yi, CHEN Yuan-yuan, HU Zhi-wei, WEN Jun, LAN Wen-gang, PAN Feng-mei, LU Yan-ran, CHEN Li-han, LI Shan, GUO Peng, FANG Shuang-xi
CO2 data from September 2020 to December 2022 were analyzed and compared before and after the COVID-19 epidemic at a typical urban monitoring station (Hangzhou) in the Yangtze River Delta. The results showed that due to the impact of COVID-19, the average CO2 concentration at Hangzhou in 2021 decreased significantly, by 12.7×10-6 (2.8%) compared with that in 2019, and achieved “zero growth” in 2022. The decrease of tourists and other population activities after the epidemic was the key factor that led to the significant decrease of CO2 concentration in summer and autumn (May to October). Compared with the pre-epidemic period, there was no significant difference in CO2 concentrations between weekdays and weekends after the epidemic, and no significant increase in CO2 concentration during peak travel hours on weekdays, indicating that the contribution of anthropogenic activities and traffic emissions to Hangzhou’s CO2 concentrations decreased significantly after the epidemic. Cluster analysis of 72 hour back trajectory revealed that the CO2 concentration at Hangzhou was not only affected by local anthropogenic emissions, but also affected by air mass transport from densely populated and industrially developed areas.
2024 Vol. 44 (7): 3563-3572 [Abstract] ( 132 ) [HTML 1KB] [ PDF 2247KB] ( 1130 )
3573 Characteristics and source apportionment of water-soluble inorganic ions in PM2.5 in central China background region
DENG Meng-jie, LEI Yu-guo, CHENG Hai-rong
To investigate the characteristics, formation mechanisms, and sources of water-soluble inorganic ions (WSIIs) in PM2.5 in the central China background area, the study conducted a one-year sampling observation at the Jinsha atmospheric background station. The results showed that the average annual mass concentration of PM2.5 was (31.40±2.05) μg/m3, showing remarkable seasonal variations of the highest level in winter and lowest in summer. Secondary inorganic aerosol (SNA, i.e., SO42-, NO3-, and NH4+) was an important component of PM2.5. The proportions of SNA in WSIIs in spring, summer, autumn, and winter were 84.0%, 77.6%, 79.8%, and 84.5%, respectively, indicating secondary formation was pronounced. The average molar equivalent ratio of anions and cations (AE/CE) during the study period was 0.91, and PM2.5 showed weak alkalinity. (NH4)2SO4, NH4NO3, and NH4Cl were the main forms of ion species in summer, while (NH4)2SO4 may be the main form in spring, autumn, and winter. The sulfur oxidation rate (SOR) and nitrogen oxidation rate (NOR) were 0.48 and 0.14, respectively, showing a significant positive correlation with PM2.5, indicating that secondary conversion was an important reason for the increase in PM2.5 concentration. The potential sources and transmission paths of WSIIs had obvious seasonal characteristics. The secondary transformation of pollutants during the migration process from the source area to the background area was obvious, and the concentration of pollutants carried by long-distance air masses from the northwest or due north was relatively high.
2024 Vol. 44 (7): 3573-3580 [Abstract] ( 140 ) [HTML 1KB] [ PDF 1569KB] ( 943 )
3581 Characteristics and sources of O3 pollution under different pollution levels and durations in typical areas of North China Plain from 2019 to 2022
QIAN Yu-xian, WANG Gang, MENG Qing-xiao, LIU Sai, WANG Yong-qiang
This study selects Juxian, Rizhao with complex terrain as the research area. Based on O3 monitoring data from provincial control stations in Juxian from 2019 to 2022, the O3 pollution days were classified according to different O3 pollution levels and durations. The pollution characteristics and sources of O3 were explored using backward trajectory model (HYSPLIT), potential source contribution function (PSCF), and concentration weighted trajectory (CWT) models. Results showed that the number of mild pollution days of O3 in Juxian decreased from 72 to 38 during the period of 2019 to 2021, while rebounded in 2022. The number of moderate pollution days of O3 have little change. Slight pollution days of O3 accounted for a high proportion of mild pollution days, with the contribution of 21.4%~39.5%, indicating a great potential for improvement for mild pollution days. Strengthening the control measures for slight pollution days will be beneficial for converting mild pollution days into excellent days and improving the local air quality excellence rate. The longer the duration of O3 pollution (e.g.,≥3d), the lower the frequency of pollution occurrence, while the O3 concentration increased with the extend of pollution duration. Simulation results of the HYSPLIT model revealed that the air mass trajectories of different O3 pollution levels and durations were mainly distributed in the southeast of Juxian and transmitted over medium and short-distances. Besides, trajectories from the southeast of Juxian contained the highest concentration of O3-8h-90% (250.0±65.9 μg/m3). The PSCF and CWT results showed that the potential source regions of O3 were mainly distributed in the southeast of Juxian, with the main potential source region appearing in the Yangtze River Delta region. The results are of great significance for guiding the joint prevention and control of air pollution in Juxian and surrounding areas.
2024 Vol. 44 (7): 3581-3591 [Abstract] ( 145 ) [HTML 1KB] [ PDF 6162KB] ( 1196 )
3592 Study on ozone precursors in Beijing based on OLI and TROPOMI satellite data
PU Dong-chuan, WANG Da-kang, ZHU Lei, YANG Xian-kun, WANG Jin-nian
Formaldehyde (HCHO) and nitrogen dioxide (NO2) are important precursors to ozone. HCHO to NO2 ratio (FNR) indicates the sensitivity of ozone production, serving as a primary reference for ozone pollution control. This study enhances the spatial resolution of TROPOMI HCHO and NO2 columns by oversampling algorithms, and reduces the uncertainty of TROPOMI data. It reveals the spatial distribution characteristics of HCHO and NO2 in Beijing during the summer of 2021. Based on FNR, the study diagnoses the sensitivity of ozone production in the Beijing areas. The study utilizes Landsat 8OLI data to calculate environmental indices and the proportion of impervious surfaces in the Beijing areas, and analyses their relationships with HCHO, NO2, and FNR. This Study aims to reveal the relationship between the degree of urbanization and the emissions of O3, VOCs, and NOx in Beijing. It finds that high NO2 columns are mainly distributed in the center of Beijing urban areas, with significantly reduced NO2 columns in non-urban areas. The mean NO2 columns increases with the proportion of impervious surfaces, but their standard deviation decreases, indicating that as urbanization in the urban areas of Beijing intensifies, the differences in NO2 emissions within urban areas diminish. The HCHO columns in urban Beijing are generally higher than those in non-urban areas, but the contribution of isoprene emissions from vegetation somewhat mitigates the disparity in VOCs emissions caused by the urbanization degree differences. Ozone in the urban area of Beijing and eastern Langfang area is controlled by VOCs, while ozone in the northern suburbs of Beijing is primarily controlled by NOx. The FNR mean decreases with an increase in the proportion of impervious surfaces, indicating that as urbanization in the Beijing area advances, the sensitivity of ozone production gradually shifts to a VOCs-controlled mechanism.
2024 Vol. 44 (7): 3592-3600 [Abstract] ( 231 ) [HTML 1KB] [ PDF 4002KB] ( 912 )
3601 Spatiotemporal variation characteristics and driving factors of near-surface ozone in Guangdong province from a multi-scale perspective
YU Rui, BU Qiao-li, CHEN Chen, MAI Bo-ru, SUN Li-ying, JIANG Ming-nuo, DENG Ruo-zhao, ZHA Jin-lin, FU Chuan-bo
The methods of Partitioning Around Medoids (PAM) clustering, Kolmogorov-Zurbenko (KZ) filtering and Generalized Additive Models (GAM) were used to explore the variability and driving factors of O3 concentration changes at various time scales and regions from 2015 to 2022 in Guangdong Province. The results were as follows: (1) Significant regional features of near-surface O3 across administrative divisions in Guangdong province were found, and 8subregions could be identified through O3 data clustering analysis. (2) The short-term component contributed the most to the total variance, followed by the seasonal component after the separation of the O3 concentration time series. (3) The correlation between meteorological variables and O3 concentration variation was influenced by both temporal scales and regional characteristics. (4) The peak concentration of O3 after meteorological adjustment mostly presented a declining trend after 2016 or 2017. The Pearl River Delta region was identified as a prominent area for O3 pollution, jointly caused by adverse meteorological conditions and anthropogenic emissions. (5) Whilst anthropogenic emissions were the main contributors to O3 concentrations, the long-term component of the O3 concentration time series generally exhibited a fluctuating upward trend, and meteorological conditions were the main drivers of O3. These findings suggest that appropriate O3 pollution prevention and control work needs to be tailored to specific times and locations, and the development of precursor reduction plans based on meteorological conditions is important in O3 pollution management.
2024 Vol. 44 (7): 3601-3614 [Abstract] ( 140 ) [HTML 1KB] [ PDF 2976KB] ( 1252 )
3615 Efficacy and mechanism of inactivation of bacterial aerosols by non-thermal plasma
JIAO Yang, JI Shuo, YU Xin, WANG He, DANG Xiao-qing, ZHANG Yu-fei
To address the issue of indoor bacterial aerosol transmission and ensure air biosafety, an experiment was conducted utilizing E. coli and Bacillus subtilis. as model strains, with non-thermal plasma employed as a means of sterilization. The study investigated the impact of input voltage, carrier gas flow rate, and initial concentration on the efficiency of bacterial aerosol inactivation. Analysis of OES, EPR, and biological characterization results revealed that reactive species (primarily including 1O2, O2-, ·OH) generated by non-thermal plasma during the inactivation process disrupted the bacteria's cell membrane leading to protein leakage, breakdown of lipids and nucleic acids ultimately resulting in complete bacterial inactivation. Increasing input voltage while decreasing flow rate could improve inactivation efficiency. However, when the initial concentration increased to a threshold, the improvement on the inactivation efficiency was negligible. The resistance of the two bacteria aerosols inactivated by non-thermal plasma was: Bacillus subtilis > E. coli. Specifically, Bacillus subtilis demonstrated an inactivation rate constant (k) of 0.0038L/J along with an energy efficiency value of 0.027 (kW∙h)/m3; whereas for E. coli these values were measured at 0.0043L/J and 0.021 (kW∙h)/m3 respectively indicating that non-thermal plasma was more effective against gram-negative bacteria such as E. coli.
2024 Vol. 44 (7): 3615-3624 [Abstract] ( 127 ) [HTML 1KB] [ PDF 1817KB] ( 1205 )
3625 PM2.5 remote sensing estimation based on spatiotemporal factor optimization model
ZHANG Na, CHEN Wen-qian, BAI Xue-song, CAO Xiao-yi
In order to obtain the continuous spatiotemporal distribution of PM2.5 concentration and improve the estimation accuracy, this paper proposes a new PM2.5 estimation model (SFRF) based on the optimization of spatiotemporal factors. The SFRF model integrates spatiotemporal factors into a random forest (RF) algorithm by integrating high-resolution (1km) satellite-retrieved aerosol optical depth (AOD) products, as well as meteorological data, nighttime light data, and vegetation. Using these data to build an SFRF model to accurately predict the PM2.5 concentration in Shandong Province in 2019 and generate high spatial resolution (1km) PM2.5 concentration in Shandong Province. The performance of the SFRF model was evaluated using the ten-fold cross-validation method and compared with the BPNN, SVM, XGBoost, RF and PCA-RF models. The results showed that the coefficient of determination and root mean square error (RMSE) values of the SFRF model verification are 0.85 and 8.10μg/m3, respectively, which are better than other models. The SFRF model can estimate PM2.5 concentration in Shandong Province with high spatial resolution on daily, seasonal, and annual scales.
2024 Vol. 44 (7): 3625-3636 [Abstract] ( 123 ) [HTML 1KB] [ PDF 6013KB] ( 780 )
3637 Study on the effect of preparation method on Ag-Cs synergistic system in soot oxidation catalysis
RUAN Hong-cheng, ZHANG Xue-ni, HUANG Dan, YANG Jun, LI Hong-hu, ZHUANG Gong-zu, BAI Quan, GUO Li-min
Bimetallic catalysts Ag-Cs/ZSM-5(E) and Ag-Cs/ZSM-5(D) were synthesized by ion-exchange and impregnation method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and so on. The catalyst activities were tested by temperature-programmed oxidation (TPO), and the catalytic activities of the bimetallic catalysts Ag-Cs/ZSM-5(E) and Ag-Cs/ZSM-5(D) were found to be significantly enhanced compared with those of Ag/ZSM-5under oxygen atmosphere, the T50 values decreased from 546℃ for Ag/ZSM-5 to 430℃ for Ag-Cs/ZSM-5(E) and 464℃ for Ag-Cs/ZSM-5(D), respectively. Meanwhile, Ag-Cs/ZSM-5(E) exhibited better catalytic activity and stability than Ag-Cs/ZSM-5(D). The results confirmed the synergistic effect of Ag-Cs bimetallic and the key role of Lewis acidic site Cs on ZSM-5 support in the bimetallic synergism.
2024 Vol. 44 (7): 3637-3645 [Abstract] ( 124 ) [HTML 1KB] [ PDF 1957KB] ( 876 )
3646 Performance and mechanism of mercury removal from flue gas by copper-enriched Acorus calamus biochar
LI Hong-hu, AN Miao, PENG Xi-yan, ZHANG Jing-dong, SUN Yang, SONG Yong-wei
The biochar containing copper sites (Cu-BC) was prepared by one-step pyrolysis of Cu-enriched Acorus calamus biomass and then utilized for elemental mercury (Hg0) removal from the flue gas. The results showed that Cu-BC (Cu-BC500) pyrolyzed at 500℃ exhibited excellent Hg0 removal performance (about 99%) at reaction temperature of 100℃. The characterization results including specific surface area analysis (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrum (FT-IR) indicated that Cu-BC500 had a relatively high specific surface area, abundant oxygen-containing functional groups and highly dispersed Cu species. XPS and Hg-TPD analyses showed that the mercury adsorbed by Cu-BC500 existed in the forms of weakly bound mercury Cu-O-Hg or copper amalgam at the surface active sites of the biochar samples. Finally, through the life-cycle cost analysis, the cost of Cu-BC500is calculated to be 3.50yuan/kg. Compared with other materials, the preparation of Cu-BC500 is simple and low-costing. The results will provide new ideas for promoting the resource reuse of water restoration plants and mercury emission reduction in coal-fired power plants.
2024 Vol. 44 (7): 3646-3654 [Abstract] ( 122 ) [HTML 1KB] [ PDF 2273KB] ( 800 )
3655 Synergistically boosting CO2 electroreduction to ethylene by CeO2-modified CuO nanorods
QI Yu, ZHANG Jin-Nan, XIAO Yuan-Yuan, ZHANG Chi, WANG Hong-Tao, GUO Tian-yu
With the development of social economy and the expansion of human activities, the concentration of CO2 in the atmosphere is increasing day by day, and it brings many environmental pollution problems, hence, developing efficient and sustainable techniques for CO2 conversion is of utmost importance. Based on the electrocatalytic reaction mechanism, a series of CuO/CeO2 nanorods were fabrication for enhancing the electrochemical reduction of carbon dioxide. The optimized CuO/CeO2-2 (molCeO2:molCuO= 2%) electrocatalyst needed the potential of -0.99V vs. RHE to achieve the current density of 20mA/cm2, and displayed the highest FEC2H4 of 46 % at the potential of -1.08V vs. RHE. The decent property is attributed to large surface area, rough surface, and synergistic effect between CuO and CeO2, thereby enhancing reaction activity sites and electron transfer efficiency. The study will provide theoretical guidance for the design and optimization of CuO-based composites for efficient CO2 conversion.
2024 Vol. 44 (7): 3655-3661 [Abstract] ( 134 ) [HTML 1KB] [ PDF 2857KB] ( 1646 )
Water Pollution Control
3662 Controlling the internal carbon source conversion of DPAOs by delayed anaerobic to achieve denitrification and phosphorus removal
LI Dong, HU Li-jun, LI Ming-run, DENG Dong-cai, MAO Zhong-xin, ZHANG Jie
This study evaluated the delay anaerobic process using an SBR reactor with simulated municipal wastewater as the influent substrate. After enrichment of PAOs, anaerobic/anoxic/aerobic operation was used to enrich DPAOs, and the internal carbon source utilization, nitrogen and phosphorus removal efficiency, and enrichment degree of DPAOs during the extension of anaerobic time were investigated. The results showed that the anaerobic time was extended from 50min to 70min and 90min, leading to an increase in the carbon source storage and utilization rate of DPAOs. The improvement of delayed anaerobic conditions resulted in an increase in the enrichment of DPAOs. The average removal rates of COD and TP during anaerobic time of 90min were 91.54% and 94.6%, respectively. DPAOs/PAOs and DPAOs contribution to internal carbon sources reached 69.4% and 60.1%, respectively. After extending the anaerobic time to 110min and 130min, the storage of internal carbon sources in DPAOs and the phosphorus removal efficiency of the system decreased. The average removal rate of TP during anaerobic time of 130min, DPAOs/PAOs and DPAOs contribution to internal carbon sources decreased to 84.6%, 50.2% and 36.4%, respectively. During the delayed anaerobic operation, the change in LB-EPS content was relatively small, and the change in internal carbon source storage had a significant impact on TB-EPS. Analysis of microbial community structure showed that the dominant phyla in the system are Bacteroidetes, Proteobacteria and Chloroflexi. DPAOs represented by Dechloromonas and Candidatus_Accumulibacter during anaerobic treatment for 90min were the dominant microorganisms in the system (relative abundance increased from 1.44% and 2.12% of inoculated sludge to 15.58% and 5.86%). When anaerobic time was extended for 130min, the abundance of DPAOs decreased, while DGAOs represented by Candidatus_Competibacter significantly increased (relative abundance increased from 3.29% in anaerobic time of 90min to 16.16%), leading to a decrease in phosphorus removal performance of the system.
2024 Vol. 44 (7): 3662-3671 [Abstract] ( 110 ) [HTML 1KB] [ PDF 1132KB] ( 1012 )
3672 Optimizing nitrogen removal in PN/A process: Step-Feed influence analysis
LI Dong, WANG Kai-lu, ZHU Yan-jun, Lü Heng-kang, ZHANG Jie
In this work, a novel model was established to optimize the C/N in the aerobic section based on the regulation of the influent distribution ratio of each aerobic section, using pre-decarbonized wastewater and municipal wastewater as target wastewater. This work was aiming at achieving the stable operation of the partial nitrification-anammox (PN/A) process under realistic conditions. Four groups of sequential batch reactors (SBR) with the same specifications run in oxic/anoxic/oxic/anoxic (O/A/O/A) mode, R1, R2, R3, and R4 operated in the step-feed mode with the influent distribution ratios (pre-decarbonized wastewater: municipal wastewater) of 1:0, 2:1, 1:1, and 1:2. The results illustrated that R1failed to realize the PN/A process and total nitrogen removal efficiency (NRE) was only 60.2%. Along with the decreasing influent distribution ratio, R2, R3, and R4 completed the PN/A process on the 34th, 30th, and 36th days, which NRE reaching 71.8%, 80.3%, and 74.1%. Among them, R3 had the optimized performance with best stability, and the contribution of anammox reaching 83.9%. It was revealed that sludge exhibited excellent settling characteristics and optimal particle size. Moreover, high-throughput data also demonstrated the abundance of ammonia-oxidizing bacteria (Nitrosomonas) and anammox bacteria (Candidatus_Kuenenia) at 2.74% and 12.17%. These microbial populations synergized effectively with aerobic heterotrophic bacteria (AHB). Hence, the step-feed model could be conductive to achieve a stable PN/A process. The influent distribution ratio of 1:1was suggested as a suitable reference value, fostering better enrichment and balance of functional microorganisms.
2024 Vol. 44 (7): 3672-3681 [Abstract] ( 113 ) [HTML 1KB] [ PDF 1809KB] ( 962 )
3682 Research advances in groundwater remediation by sulfidized nanoscale zerovalent iron
CHEN Zong-ding, KONG Xiang-ke, XU Chun-xue, ZHANG Zhao-ji, HUANG Yuan-ying, SUN Hui-zhong, AN Zi-yi
Compared with the traditional nanoscale zerovalent iron (nZVI) materials, sulfidized nanoscale zerovalent iron (S-nZVI) has the advantages of high activity and electron selectivity, which has attracted much attention in the remediation of groundwater contamination. Based on the systematic summary of the main synthesis and modification methods of S-nZVI, the reaction mechanism of S-nZVI with chlorine-containing organic pollutants and heavy metals was summarized. The synthesis process of S-nZVI (sulfidation method, sulfur precursors and S/Fe ratio) and the water environmental factors (pH and chemical components) are the important factors influencing the reactivity of S-nZVI with pollutants. In addition, the application prospects of S-nZVI in the groundwater remediation were reviewed from the aspects of its stability, mobility and biologic toxicity. Finally, the future research directions of S-nZVI were prospected to support the application of S-nZVI for in situ groundwater remediation.
2024 Vol. 44 (7): 3682-3697 [Abstract] ( 145 ) [HTML 1KB] [ PDF 848KB] ( 1549 )
3698 Research on the application of the PN/A process in projects of sludge-digestion liquid treatment by thermal hydrolysis
WANG Xiao-cong, HAN Xiao-yu, ZHANG Shu-jun, LI Wei, HUANG Jing, JIAO Jia-tong, WANG Qian, WANG Zhi-min, QU Zhi-ming
The partial nitrification-anaerobic ammonium oxidation (PN/A) process was successfully launched in a sewage treatment plant in Beijing for the treatment of sludge-digestion liquid treatment by thermal hydrolysis. The optimal operation conditions were proposed based on the project commissioning. Specifically, the PN/A system could be quickly initiated when the proportion of biofilm-inoculated carrier was 18% of the total carrier and the relative abundance of anaerobic ammonium oxidation bacteria (AnAOB) on the biofilm reached 6.8%. The designed water treatment capacity could be achieved within 3months, where the total nitrogen removal load was 0.26kg/(m³·d) and the total nitrogen removal efficiency reached 80%. Quantitative PCR and high-throughput sequencing analysis showed that different spatial distribution characteristics of AOB and AnAOB abundance, and proportions of both ammonia oxidizing bacteria (AOB) and AnAOB increased steadily during the commissioning; and the respective abundance of AOB in flocs and AnAOB on the biofilm reached the magnitude of 1011 and 1012 after 3 months of cultivation. Data from practical operation demonstrated that the sidestream treatment system has a positive impact on the mainstream, where a 2.9 mg/L decrease of the total nitrogen was observed with the influent for a sewage treatment plant of 40×104t/d. At the last running stage of the project, an insufficient supply of free ammonia (FA) was observed in the anoxic zone of the reaction tank, which resulted in the unstable performance of the PN/A system. However, the system could be quickly restored by controlling the FA concentration at the beginning and end of the reaction tank and the remaining ammonia nitrogen concentration.
2024 Vol. 44 (7): 3698-3706 [Abstract] ( 134 ) [HTML 1KB] [ PDF 1624KB] ( 1012 )
3707 Effect and mechanism of different chemical agents on substrate clogging mitigation in constructed wetlands
ZHOU Shuai-feng, LIU Yuan, ZHANG Sheng-hao, ZHANG Bing, SHI Wen-xin
In this study, the horizontal subsurface flow constructed wetland was used as the research object to explore the effect and mechanism of sodium dodecyl sulfate (SDS), sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) on substrate clogging mitigation, and to analyze its engineering application feasibility. Results showed that the permeability coefficient of the substrate layer increased by 53.3%, 27.5% and 210.7%, respectively, after treatment with these three chemical agents. H2O2 had the minimal effect on the removal efficiency of pollutants in the reactor and improved the removal efficiencies of ammonia nitrogen and total phosphorus. The addition of the three agents caused slight damage to the plants, but this negative effect could be elastically restored in the short term period (14days) (93.8%, 84.4% and 84.4%, respectively).In terms of microbial community structure, chemicals treatment alleviated clogging by inhibiting the growth of biofilm-forming bacteria (such as Pleomorphomonas and norank_f__norank_o__Saccharimonadales), and restored reactor performance by improving the anaerobic environment of the reactors and promoting the growth of nitrogen and phosphorus removal functional bacteria (such as denitrifying bacteria unclassified_f__Comamonadaceae).Combined with the clogging mitigation effect and the feasibility of engineering application, it was considered that H2O2 was the best agent to alleviate the substrate clogging of constructed wetlands among the three agents.
2024 Vol. 44 (7): 3707-3718 [Abstract] ( 125 ) [HTML 1KB] [ PDF 3158KB] ( 998 )
3719 Achieving stable partial nitrification by combining heat-shock sludge and intermittent gradient aeration
LI Dong, ZHANG Jing-zhao, ZENG Fan-xu, LI Zhu, ZHANG Jie
A novel strategy combining heat shock and intermittent gradient aeration was proposed to achieve partial nitrification. The impact of the combined strategy on nitrifying bacteria was explored in a 120-day experiment. Furthermore, the long-term stability of partial nitrification under the combined strategy was optimized by adjusting the sludge discharge ratio as the primary variable. The results demonstrated that intermittent gradient aeration (DO: 2.0mg/L// DO: 1.2mg/L// DO: 0.5mg/L) could rapidly restore the activity of ammonia-oxidizing bacteria impaired by thermal treatment without external carbon source added, and NAR achieved over 80% in 5days. During the stabilization phase, SAOR and SNPR were 30.12 and 6.69mg N/(gVSS⋅h), respectively. And the effluent ammonia concentration was below 0.1mg/L with nitrite and nitrate concentration of 53.42 and 8.01mg/L. Further analysis showed that the NAR remained at 88.96% when the sludge discharge ratio was set at 1%, while it tended to decrease with the discharge ratio of 0.5% or another value of 1.5%.
2024 Vol. 44 (7): 3719-3728 [Abstract] ( 119 ) [HTML 1KB] [ PDF 1989KB] ( 1048 )
3729 Nonradical-dominated peroxymonosulfate activation by FeMn nanoparticles for the degradation of organic pollutants
LIN Shuang-jie, WANG Yong-quan, ZENG Jing, CAI Lan-yan, HONG Jun-ming
Mesoporous FeMn nanoparticles (FMNPs) with high catalytic activity and stability were successfully synthesized by a two-step hydrothermal-calcination method. The physicochemical properties, morphology, and structure of FMNPs were analyzed by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Specific surface and pore size analyzer (BET), Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffractometry (XRD). The synthesized catalysts, featuring abundant mesopores and a large specific surface area, significantly enhanced the catalytic degradation of organic pollutants. To assess the reusability, stability, and adaptability of the catalysts, degradation experiments were conducted with reactive black 5 (RBK5) under various conditions. The optimal parameters were established at a pH of 7, a persulfate (PMS) concentration of 2mmol/L, and a catalyst dosage of 0.2g/L, achieving a 96.74% removal of 10mg/L RBK5 within 60 minutes. The catalytic mechanism was investigated through Electron Paramagnetic Resonance (EPR), quenching experiments, and Chronocurrent (i-t) tests, confirming that the non-radical pathway (1O2 and mediated electron transfer) played a dominant role in the degradation process. X-ray photoelectron spectroscopy (XPS) analysis revealed that the synergistic effect between Fe and Mn promoted the redox cycle of Fe3+/Fe2+ and Mn2+/Mn3+, accelerating the electron transfer to PMS and thereby boosting the activation efficiency of PMS.
2024 Vol. 44 (7): 3729-3740 [Abstract] ( 138 ) [HTML 1KB] [ PDF 1696KB] ( 1898 )
3741 Synergistic adsorption of Sb(V) using wet ball milling of manganese slag supported by biochar
LU Hong-yu, CHENG Hong-guang, GRATIEN Twagirayezu, FANG Xin, HUANG Sheng-lan, DENG Lin-bo, JI Bo
This study used wet ball milling to synthesize ball-milled biochar-based manganese slag composites (QBM) with a 1:1ratio of biochar to manganese slag. The goal was to improve the adsorption efficiency of Sb(V) and the resource utilization of waste manganese slag. Herein, physicochemical properties, leaching toxicity, and Sb(V) adsorption properties of the composite materials were discussed. The composite materials exhibited a reduction of 9.7%, 63.9%, 15.2%, and 70.9% in pH value, conductivity, cation exchange capacity, and particle size, respectively, after being wet ball milled at room temperature for 8hours with a solid-liquid ratio of 1:6 and a rotation speed of 150r/min. Zeta potential significantly increased (P<0.05) between –15 and -21mV. Ball milling effectively reduced the leaching of manganese ions and ammonium nitrogen in the manganese slag from 415mg/L to 2mg/L and 82mg/L to 15mg/L, respectively, which is the levels below the standard "Integrated Wastewater Discharge Standard" (GB8978-1996). Moreover, the Sb(V) removal rate significantly increased from 31.86% to 80.98% (P<0.05). Wet ball milling improved Sb(V) adsorption efficiency and safety by enhancing the physicochemical properties of materials. This study suggests that biochar-assisted wet ball milling of manganese slag can effectively mitigate Sb(V) antimony pollution in the environment. This provides the idea that manganese slag can be used as a resource to reduce environmental pollution.
2024 Vol. 44 (7): 3741-3748 [Abstract] ( 183 ) [HTML 1KB] [ PDF 2064KB] ( 751 )
3749 Membrane fouling mechanisms on organic matter in the secondary effluent by GAC-NF combined process
SUN Li-hua, DENG Si, MEI Xiao-yu, WANG Chun-fang
This study utilized two types of filtration units (GAC and BAC) in combination with NF to evaluate the effects of three different treatment processes (direct NF, GAC-NF, BAC-NF) on organic compounds in the secondary effluent from wastewater treatment plant, as well as analyze the mechanisms of membrane contamination. Based on the findings, BAC-NF exhibited the highest removal efficiencies for DOC, microbial metabolism by-products, and humic acids, with the removal rates of 85.2%, 76.2% and 82.0%, respectively. BAC-NF offered the greatest membrane specific fluxes of 0.69, 0.65 and 0.63 at the end of each cycle, whereas the total membrane contamination resistance was the lowest (5.97×1010m-1). In addition, the characteristic curve of membrane contamination suggests that the direct NF was filter cake layer pollution, which is attributed to the middle blockage caused by GAC-NF and BAC-NF. It is noteworthy that the membrane middle pore blocking was dominant for BAC-NF, whereas the degree of membrane pollution was the mildest. According to xDLVO theory, the membrane surface polluted by BAC-NF offered the lowest hydrophobicity, corresponding to the highest Zeta potential. The organic matters in water were less reachable to membrane surface at the initial filtration stage using BAC-NF technology, resulting in less membrane pollution. During the middle and late stages of filtration, the adhesion of organic matters in water and on membrane surface rarely occurred, leading to the formation of loosest cake layer. Overall, BAC-NF is able to effectively mitigate membrane contamination, holding the potential for advanced treatment and reuse of reclaimed water.
2024 Vol. 44 (7): 3749-3758 [Abstract] ( 136 ) [HTML 1KB] [ PDF 1684KB] ( 833 )
3759 Mechanism of the effect of graphene oxide on nitrogen removal performance of activated sludge
YIN Mu-chen, LI Jun, WU Yao-dong, LI Dong-yue, GAO Peng, BIAN Xue-ying, PEI Yan-xue, LIANG Dong-bo
Three sequencing batch reactors (SBRs) with different concentrations of graphene oxide (GO. 0.1 and 10mg/L) were established to clarify the intrinsic mechanism of GO deteriorating the nitrogen removal performance of activated sludge (AS). The results showed that 1mg/L GO had no significant inhibitory effect on the performance of AS. 10mg/L GO reduced the total nitrogen (TN) removal efficiency of AS by 17.63%. Moreover. GO exposure increased the oxidative stress levels in AS by 198.51% and 307.13%. respectively. The microorganisms responded to the GO stress by secreting more extracellular polymers (EPS). 16S rRNA gene sequencing showed that GO significantly affected the abundance of genera with nitrogen removal function. The abundance of common genera responsible for nitrification (Nitrosomonas and Nitrospira) and denitrification (Candidatus_Accumulibacter. and Thauera. etc.) decreased with increasing GO concentration. Functional gene prediction showed that GO reduced the abundance of genes related to nitrogen removal. The abundance of genes related to NH4+-N oxidation (amoA.
2024 Vol. 44 (7): 3759-3766 [Abstract] ( 113 ) [HTML 1KB] [ PDF 1761KB] ( 1095 )
3767 Efficient removal of sulfadiazine by water hyacinth
ZHANG Yue, YUAN Yu-long, YAN Cai-xia, JIANG Yi-han, SU Mei-qi, DING Ming-jun, WANG Peng, NIE Ming-hua
Water hyacinth biochar (EBC), derived from the invasive plant water hyacinth, exhibited remarkable capabilities in activating periodate (PI) and facilitating the degradation of sulfadiazine (SD). Notably, EBC outperformed Alligator weed BC and Canadian goldenrod BC in this regard. Among various pyrolysis temperatures, EBC prepared at 500℃(EBC500) demonstrated superior PI activation, effectively removing SD within a mere 20 minutes using a lower PI dose (0.15mmol/L). As the dosage of EBC500 and PI increased, the removal rate of SD also increased accordingly. Comprehensive analyses, including bursting experiments and electron paramagnetic resonance analysis, revealed that iodine radicals (×IO3, ×IO4), superoxide radicals (O2•−), and singlet oxygen (1O2) served as the primary reactive species responsible for the degradation of SD in the EBC500/PI system. Meanwhile, under the conditions of EBC500 and PI dosages of 0.15g/L and 0.15mmol/L, respectively, SD can be completely removed across a wide range of initial pH values (5~9). Coexisting substances such as common anions (including Cl−, SO42−, and NO3−) had minimal impact on the degradation of SD in the EBC500/PI system. However, HCO3− and HA exhibited inhibitory effects on the removal of SD. Moreover, the EBC500/PI system demonstrates robust applicability for the degradation of SD in natural water matrixes, and good application potential for degradation of other typical sulfonamide antibiotics as well. Additionally, EBC500 demonstrated favorable reusability. Based on the identification of six intermediates, potential degradation pathways of SD were proposed. Ecotoxicity analysis and plant seed germination tests confirmed that the treatment with the EBC500/PI system significantly reduced the biological toxicity of SD, underscoring its promising application prospects.
2024 Vol. 44 (7): 3767-3779 [Abstract] ( 114 ) [HTML 1KB] [ PDF 1525KB] ( 1075 )
3780 Effect of short-term exposure to thallium on SBR activated sludge performance
ZHAO Xiao-jing, LUO Yuan-ling, WU Hong-hui, DING Yu-ting, XIANG Ke-yi, HUANG Jun-guo, GAO Jia-ni, JIA Mei-ying, HU Xin-jiang, ZHU Jian, WANG Ping, XU Hai-yin
In this study, using the Sequencing Batch Reactor (SBR) process as an example, the short-term disturbances and recovery behavior of activated sludge performance with respect to Tl exposure concentration were investigated, focusing on nitrogen and phosphorus removal, microbiological and enzyme activity. The results indicated that both nitrogen and phosphorus removal efficiency and COD removal rate of activated sludge were susceptible to the influence of Tl. When Tl was at a concentration of 500μg/L, nitrogen and phosphorus removal processes were inhibited, but upon the elimination of Tl exposure, the performance could recover. However, at a Tl concentration of 1000μg/L, although the phosphorus removal efficiency could be restored to 65%, the nitrogen removal process was completely inhibited and the inhibition of the nitrogen removal process was irreversible. Low concentrations of Tl increased the COD removal rate, and the effect of high concentrations of Tl on the COD removal rate was reversible. Furthermore, a Tl concentration of 200μg/L was found to increase microbial activity, but at 1000μg/L, Tl led to a significant reduction in the relative production of catalase and superoxide dismutase by 71.9% and 30.8%, which greatly inhibited microbial activity. The specific oxygen uptake rate was highly sensitive to the presence and elimination of Tl, making it an indicator for Tl exposure in wastewater treatment plants. Characterization through Fourier-Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy revealed that Tl bound to hydroxyl groups in extracellular polymeric substances or oxidized from Tl+ to Tl3+, which might have been the mechanism by which activated sludge mitigated Tl cytotoxicity. Therefore, when exposed to short-term Tl, it was necessary to enhance the nitrogen and phosphorus removal performance of activated sludge and strengthened its ability to remove Tl to ensure the stable operation of wastewater treatment plants. This study revealed the potential impacts of short-term Tl exposure on activated sludge systems and proposed mitigation strategies.
2024 Vol. 44 (7): 3780-3785 [Abstract] ( 102 ) [HTML 1KB] [ PDF 845KB] ( 712 )
3786 The mechanism of nitrogen migration aceoss sediment-water core manipulated by oxygen-loaded zeolite
YANG Bing, LUO Jun-xiao, TANG Bing-ran, DENG Lian-jun, GE Miao, LIU Qiang, ZHANG Xiao-ling, HE Qiang, LI Hong
Dissolved oxygen is essential for the migration of nitrogen in the sediment. In this study, we prepared oxygen- loaded zeolite using three kinds of fly ash, then explored the removal efficiency and mechanisms toward nitrogen in sediment-water systems by capping the surface sediment with the oxygen- loaded zeolite (with thicknesses of 0.5, 1.0, and 2.0cm). The results showed that the oxygen-loaded zeolite was able to reduce the nitrogen content in the sediment-water system and control the release of nitrogen from the sediment through the adsorption and oxygen release, and the effect is positively correlated with the thickness of the capping materials. The dissolved oxygen concentrations at the sediment-water interface in the 0.5, 1.0, and 2.0cm thickness treatment groups reached 1.79, 3.69, and 6.26mg/L after 25 days of incubation, respectively. Meanwhile, the removal rate of total nitrogen in the overlying water was 22.77% in the 0.5cm thickness group, 30.37% in the 1cm thickness group, and 39.10% in the 2cm thickness group. Compared with the control group, the ammonia release flux across the sediment-water interface was reduced by 31.4%, 47.0%, and 50.47%, respectively. In addition, the oxygen- loaded zeolite increased the abundance of microorganisms involved in nitrification and denitrification. The abundance of nitrification functional genes (amoA), denitrification functional genes (narG, napA, nirS, and nirK), and aerobic denitrification genes (napA) in the surface sediments was substantially promoted, demonstrating that a coupled aerobic-anoxic denitrification process may occur in the surface sediments. The results from this study may provide a new perspective for the utilization of fly ash and management of the international nutrients loading.
2024 Vol. 44 (7): 3786-3799 [Abstract] ( 130 ) [HTML 1KB] [ PDF 1944KB] ( 1180 )
3800 Characterization of raw water biofilm pretreatment processes in response to organic carbon sources: An example of nitrogen removal performance and bacterial community structure
YE Li-hui, LIU Xin-ling, LIN Si-hui, SHI Hai-yang, ZHAO Yi-chun, CHEN Dong-zhi, YANG Guang-feng
The operation performance of the raw water pretreatment biofilm system is limited by the water quality of raw water. A laboratory-scale raw water pretreatment biofilm system was constructed with synthetic polluted raw water as the treatment object and comet type fiber filler and activated carbon filler as biofilm carriers. Batch tests were conducted to explore the response characteristics of operation performance and bacterial community structure to different organic carbon sources including sodium acetate and humic acid. Experimental results showed that the raw water pretreatment biofilmsystem operated stably for a long time with the average ammonia nitrogen removal efficiency (ARE) of 90.1%. Sodium acetate had little effect on the ammonia nitrogen removal performance of biofilm attached on two kinds of carriers. Stronger nitrification ability with the highest ARE of 90.5%±5.6% was obtained using humic acid as the organic carbon source. Using comet type fiber filler as biofilm carrier, sodium acetate promoted the formation of extracellular polymer (EPS) in biofilm, and humic acid reduced the PN content in EPS. The usage of activated carbon as the biofilm carrier significantly increased the PN/PS value of EPS, and had higher bacteriall diversity, which was more conducive to the formation of biofilm. In the biofilm samples, the top three phyla are Proteobacteria, Planctomycetes, and Acidobacteria. When comet type fiber filler was used as biofilm carrier, sodium acetate and humic acid enhanced the accumulation of Proteobacteria (53.9%) and Nitrospira (10.7%), respectively. The dominant genera of biofilm samples of comet type fiber filler and activated carbon were Nitrospira and Aridibacter, respectively. Humic acid was more conducive to the enrichment of Nitrospira and Bdellovibrio, and sodium acetate was more conducive to the enrichment of Aridibacter.
2024 Vol. 44 (7): 3800-3809 [Abstract] ( 115 ) [HTML 1KB] [ PDF 1614KB] ( 918 )
3810 Hydrochemical characteristics and fluorine genesis of different water bodies in coal-fired power agglomeration area of Northwest China
HAN Xuan, HUANG Lei, LIU Ting-xi, HOU Ze-ming, LI Yan-na, XU Jiang
In order to explore the hydrochemical characteristics of different water bodies and the causes of fluorine ion distribution in the Northwest coal-electricity agglomeration area, the Bulianta mining area in Ordos City was taken as the research object. The Piper three-line diagram, principal component analysis, correlation analysis and other methods were used to test the collected 55water samples, and the non-carcinogenic health assessment model was used to evaluate the health risk of fluorine ions in groundwater. The results show that all water samples were weakly alkaline; Na+ and SO42- were the dominant ions of surface water and deep groundwater, and the dominant ions of shallow groundwater were Ca2+ and HCO3-. The hydrochemical types of surface water were mainly SO4Cl-Na and HCO3SO4-Na. There are many chemical types of shallow groundwater, mainly SO4Cl-Na·Ca, HCO3-Na·Mg, HCO3-Mg and SO4Cl-Ca, while the deep groundwater is mainly HCO3SO4-Ca and SO4-Na. Its hydrochemical characteristics are mainly due to the influence of silicate weathering and dissolution, and coal mining activities promote the interaction between different water bodies. The variation ranges of F-in surface water, shallow groundwater and deep layer were respectively 0.16 ~4.82, 0~0.69, 0.08~6.26mg/L in surface water, shallow groundwater and deep layer, respectively. 19.35% of the risk index of F- in groundwater exceeded HQ=1, and it is assumed that the high fluorine phenomenon in groundwater in this area has certain impacts on human health.
2024 Vol. 44 (7): 3810-3822 [Abstract] ( 136 ) [HTML 1KB] [ PDF 2522KB] ( 789 )
3823 Characterization of spatial and temporal distribution of nitrogen and source analysis of nitrate in a typical water diversion receiving basin: A case study on upper reaches of Fenhe Reservoir
YANG Xiao-yu, SUN Hui, WANG Yan, ZHANG Feng, WANG Chao-xu, CHAI Jia-lin, ZHENG Jia-xiao
This study investigated the temporal and spatial distribution characteristics of nitrogen in the upstream basin of the Fenhe River Reservoir in the receiving area of the Wanjiazhai Yellow River Diversion Project. It identified the sources of nitrate and analyzed the impact of Yellow River water diversion on the local basin. Results indicated that the mean concentration of total nitrogen (TN) in each county of the basin was 3.67mg/L throughout the four seasons, with nitrate-nitrogen (NO3--N) accounting for over 70% of TN on average. Spatially, Ningwu County had the highest mean TN concentration, which gradually decreased downstream. Temporally, TN concentrations were higher in autumn and winter and lower in summer, with nitrogen carried by Yellow River water during the diversion period being the primary nitrogen source in the basin. Qualitative analysis revealed that the mixing process of various pollution sources was the main factor affecting nitrogen migration. Quantitative calculations using the MixSIAR model showed that the average contribution rates of various sources to NO3--N were as follows, from highest to lowest: wastewater discharge and point sources (39.3%) > livestock manure (18.7%) > chemical fertilizers (18.2%) > soil organic nitrogen (17.7%) > atmospheric nitrogen deposition (6.1%). In Yellow River water, the contribution rates of wastewater discharge and point sources in autumn and chemical fertilizers in spring to nitrate were significantly higher than those in local tributaries, indicating a greater impact of Yellow River water diversion on the nitrate sources in downstream sections of the main stream.
2024 Vol. 44 (7): 3823-3831 [Abstract] ( 135 ) [HTML 1KB] [ PDF 1815KB] ( 916 )
3832 in Xinjiang
KANG Wen-hui, ZHOU Yin-zhu, LEI Mi, HAN Shuang-bao, ZHOU Jin-long
Groundwater is one of the major water sources for production, living and agricultural irrigation in the Manas River Basin in Xinjiang. Due to the influence of regional environmental background and long-term effect of human activities, high arsenic (As), Fluoride (F) and iodine (I) in groundwater is the main issue of groundwater quality. To better understand the distribution and enrichment genesis of As, F and I in groundwater in the Manas River Basin, the hydrochemical and spatial distribution of groundwater with high As, high F and high I were analyzed via correlation analysis and geochemical simulation. Moreover, source, migration and enrichment processes of groundwater As, F and I were further clarified with the combination of geological conditions and groundwater occurrence environment. Results showed that the variation ranges of As, F and I in groundwater are 1.13 to 41.35μg/L 0.06 to 8.02mg/L, and < 0.025 to 0.249mg/L, respectively. Over-limit rate of groundwater As, F and I were 62.9%, 45.7% and 45.7%, respectively. Groundwater samples high in As, F and I had the over-limit rate of 31.4%. Groundwater with the co-enrichment of As, F and I was mainly distributed in the plain area near the desert edge in the eastern part of the Manas River Basin with the primary hydrochemistry type of HCO3·SO4·Cl-Na. From single structure phreatic in the piedmont area to confined groundwater in the plain area, groundwater As increased along the flowpath and decreased near the desert edge. Horizontally, groundwater leaching led to the enrichment of As from As-rich strata in the piedmont area in the south to the confined groundwater area, and the reduction process of SO42- under alkaline environment contributed to the desorption of As. Groundwater F increased gradually along the flowpath, reaching 2.5mg/L at the edge of Gurbantunggut Desert. Reduction environment with high HCO3-, Na+ and pH was the major reason for F release from aquifer matrix to groundwater. Groundwater I showed an increase trend along the flowpath generally. Enrichment of I in phreatic water in the confined water area was mainly affected by evaporation and concentration, while that in confined groundwater was mainly affected by rock weathering. Groundwater with As-F-I co-enrichment was mainly distributed in confined groundwater at the depth of 100 to 300m. In the closed confined aquifer, , mineral dissolution and precipitation and water-rock interaction under alkaline-reducing environment were the main mechanism for groundwater As-F-I co-enrichment.
2024 Vol. 44 (7): 3832-3842 [Abstract] ( 121 ) [HTML 1KB] [ PDF 5333KB] ( 1014 )
3843 Comparison and source apportionment of groundwater quality in urban construction waste landfill areas
WEI Xiao-qian, JIANG Jian-fang, FENG Xiao-jia-wen, XU Ming-ming, LI Shuo, LIU Bing, BAI Kai-wen, HOU Li-li, ZHAO Wen-ji
In this study, two landfill sites mainly disposing construction and demolition wastes (CDW) were selected from two typical small or medium-sized cities in China. An entropy weighted water quality index was used to evaluate the groundwater quality in surrounding areas of the two sites. An integrated source apportionment approach was developed to reduce the uncertainty of the inverse modelling process. The sources of chemical composition in groundwater was firstly identified using multivariate statistical methods such as cluster analysis. Then a positive matrix factorization (PMF) model was used for source apportionment calculation, quantifying the contributions of two CDW landfills to changes in groundwater compositions in surrounding areas. Results showed that CDW landfill site could make groundwater quality deteriorate, with the degree of the impact depending on a variety of factors such as site properties, landfill history, and contamination prevention capacity of vadose zone. The overall deterioration of groundwater quality in the surrounding area of site 1was more severe than that of site 2. The concentration of seven monitored compositions in site 1exceeded the class III standard limit of the groundwater quality standard (GB/T 14848-2017), while only one composition in site 2exceeded the limit. The PMF source analysis identified five natural and anthropogenic sources for the chemical compositions of groundwater in both locations, namely dissolution of minerals in soils and rocks, solute transport, agricultural sources, CDW sources and industrial sources. The contributions of these sources were 18.2%, 18.0%, 25.9%, 19.5% and 9.8% in site 1, and 19.8%, 23.5%, 18.9%, 12.6% and 15.1% in site 2, respectively. The impact of human activities and CDW landfill on the groundwater surrounding site 1is greater than that on site 2.
2024 Vol. 44 (7): 3843-3857 [Abstract] ( 111 ) [HTML 1KB] [ PDF 3242KB] ( 1007 )
3858 The performance of tetrachloroethylene solubilization in the aquifer by in-situ microemulsion of composite alcohols
SUN Ri-hong, DONG Jun, ZHANG Wei-hong, MO Yan-yang, YU Tong
In this study, a green nonionic surfactant, Lauryl glucoside (APG1214), was used to prepare an in-situ microemulsion of composite alcohols suitable for the remediation of tetrachloroethylene (PCE) contamination in groundwater. The effects of environmental factors on the phase behavior and solubilization of microemulsion were investigated. Besides, by simulating the aquifer, the performance of microemulsion in-situ leaching PCE was investigated. The results showed that 1.0wt. % APG1214-5.6 wt.% n-propanol/isobutanol (1:1) -0.8wt. % NaCl microemulsion had suitable alcohol width, and the solubility of PCE was about 550g/L. It showed good performance in reducing the adsorption of aquifer media, controlling vertical migration of pollutants, and preventing secondary pollution. The phase stability of the microemulsion was not significantly affected by environmental factors, but its solubilization was reduced in strong acid and low-temperature environments. Moreover, the in-situ leaching process removed PCE in the media by solubilization and mobilization, and the removal efficiency of PCE reached 99.4% after leaching. In all, the microemulsion has the advantages of strong solubilization ability, wide alcohol width, low surfactant dosage, wide environmental application range, and high removal efficiency of PCE after in-situ leaching, which makes it suitable for remediating PCE pollution in groundwater.
2024 Vol. 44 (7): 3858-3866 [Abstract] ( 112 ) [HTML 1KB] [ PDF 1156KB] ( 824 )
3867 Research progress on biofilm thickness control in membrane aerated biofilm
ZHAI Xin-yu, WEI Chun-hai, GUO Qi-qi, RONG Hong-wei, LUO Min, BAO Jin-feng, QIU Yong, HUANG Xia
Biofilm thickness control is crucial to the successful operation and management of membrane aerated biofilm reactor (MABR) process. There is the optimal biofilm thickness to achieve the best simultaneous removal of carbon, nitrogen and phosphorus. The research and development of MABR biofilm thickness control technology (including periodic scouring, continuous hydraulic shear, eukaryotic predation, and quorum quenching) in the past 20 years are reviewed in this article. Future research and development directions on MABR biofilm thickness control are explored to provide references for the high-quality development of MABR process towards the goals of improving water quality, saving energy and reducing carbon emission.
2024 Vol. 44 (7): 3867-3878 [Abstract] ( 184 ) [HTML 1KB] [ PDF 1280KB] ( 933 )
Solid Waste
3879 Research progress on the regulation of estrogen degradation in aerobic composting of livestock and poultry manure
LI Mao, ZHOU Jia-liang, DING Guo-chun, ZHAO Xiao, LIU Hong-bin, DUAN Na
Recent achievements related to livestock and poultry manure and its composting were collected and analyzed. The physicochemical properties of estrogens and their presence in livestock and poultry manure were summarized. The effects and mechanisms of composting process parameters, different additives, and co-existing pollutants on the degradation of estrogens during the composting of livestock and poultry manure were elucidated. The estrogens posing significant threats in livestock and poultry manure are mainly estriol, estradiol, and estrone. Maintaining a high-temperature duration of no less than 8d during the composting process is more conducive to estrogen degradation. Among additives, inoculating microbial agents owns the best results for estrogen degradation. Coexisting pollutants such as heavy metals, microplastics, and antibiotics generally inhibit estrogen degradation. Nonetheless, further research on estrogen degradation in livestock and poultry manure composting is necessary. Based on existing studies, the future perspective is proposed.
2024 Vol. 44 (7): 3879-3891 [Abstract] ( 147 ) [HTML 1KB] [ PDF 2185KB] ( 1095 )
Soil Pollution Control
3892 Study of heat and moisture transport of superheated steam in porous media
CHEN Zhi-xin, HU Li-ming
The significant process for the thermal remediation of organic-contaminated soil using steam enhanced extraction technique is the heat and moisture transport of superheated steam within porous media. A two-dimensional experimental system was developed and a series of tests are conducted to investigate the transport behavior of superheated steam in porous media with different particle size. The findings reveal that injecting superheated steam at a constant flow rate quickly increases the temperature of the glass bead assemblies in the model, though the steam pressure increases at a slower rate than the temperature at the same location. The patterns of vapor pressure changes within the glass bead assemblies align closely with temperature variations, suggesting that heat transfer is primarily driven by the latent heat released during vapor migration. Additionally, thermal infrared imaging effectively tracks the progression of the temperature field during steam migration. Smaller particle sizes tend to slow the advance of both the steam condensation and superheated steam fronts.
2024 Vol. 44 (7): 3892-3899 [Abstract] ( 99 ) [HTML 1KB] [ PDF 2990KB] ( 961 )
3900 Adsorption performance and mechanism of heavy metals by manganese-loaded carbonized soil
YU Zhen-zhen, YANG Yi-fan, GAO Hang, WANG Ming-xin
In this study, a combination of permanganate pretreatment and oxygen-limited pyrolysis was used to treat and convert petroleum-contaminated soil (PCS) into carbonized soil loaded with manganese oxides (Mn-CS). Compared with the carbonized soil (CS) obtained by solo pyrolysis treatment, the Mn-CS is rough and porous, with higher specific surface area, micropore volume and lower leaching risk of soluble organic matter. The adsorption properties of Mn-CS for heavy metals can be well fitted by Langmuir isotherm model and pseudo-second-order kinetic model. The maximum theoretic adsorption capacity of Mn-CS for Pb2+, Cu2+, Zn2+and Cd2+is 420.54, 81.19, 79.73 and 26.40mg/g, respectively. The adoption processes are dominated by single-layer chemical adsorption. The heavy metals adsorbed by Mn-CS are mainly bound to Fe/Mn oxides, followed by bound to carbonate and organic matter. The adsorption mechanism includes surface complexation, coprecipitation and mineral binding/precipitation. Permanganate pretreatment significantly enhances the adsorption performance by increasing carbonate, manganese oxides and amorphous carbon on the surface of soil. Thus, the adsorption capacity of Mn-CS for heavy metals is synergistically improved. This study provided a new method to realize the value-added transformation of PCS, which is supposed to promote PCS treatment mode from up-to-standard remediation to resource utilization.
2024 Vol. 44 (7): 3900-3909 [Abstract] ( 121 ) [HTML 1KB] [ PDF 1104KB] ( 1004 )
3910 Characterization and source analysis of topsoil heavy metal pollution in Nanjing, Yangtze River Delta Region
YANG Yu-ying, LIU Liang, CHEN Ming, LAI Juan-juan, WANG Yan-yu, HAO Yan-fang
This study examined the pollution characteristics of heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in the shallow soils of Nanjing’s urban core, a typical industrial city in the Yangtze River Delta. The sources of heavy metals in the soil were interpreted using kriging and multivariate statistical analysis methods. The results showed that Cd, Cr, Cu, Mn, Ni, Pb, and Zn were all enriched in the soil of the main urban area of Nanjing, with average contents of 0.24, 76.9, 36.45, 707.22, 35.48, 32.65, and 99.75mg/kg, respectively. From the perspective of spatial distribution characteristics, it was found that the contents of heavy metal elements Zn, Cu, Cd, and Pb in the soil of Nanjing were higher in industrial areas. High values of Zn, Cu, and Pb were observed in the old urban areas. The contents of Ni and Cr were generally higher in industrial areas and lower in the old urban areas. The distribution trend of Mn was relatively gentle and significantly different from the other six heavy metal elements. Based on the results of principal component analysis and cluster analysis, it could be determined that Zn, Cu, Cd, and Pb in the soil of Nanjing were mainly affected by industrial and transportation activities. Ni and Cr were primarily influenced by industrial activities, while Mn was mainly from natural sources. Industrial and transportation activities were identified as important causes of heavy metal pollution in the soil of industrial cities in the Yangtze River Delta region. They were also crucial directions for the prevention and control of soil heavy metal pollution in the Yangtze River Delta region.
2024 Vol. 44 (7): 3910-3918 [Abstract] ( 110 ) [HTML 1KB] [ PDF 5514KB] ( 933 )
Environmental Ecology
3919 Sources, preservation, and influencing factors of organic carbon from the Dagu River Basin
HUANG Tie-han, LIU Ke, LI Li, XIAO Xiao-tong
In this study, surface water, suspended particulate matters and sediments were collected in the Dagu River of Shandong Peninsula during the dry (May) and wet (September) seasons in 2022 for the determination of total organic carbon (TOC) and nitrogen (TN), stable carbon isotopes (δ13C), biomarkers, and mineralogical parameters. The results showed that the sources of organic matter in the surface suspended particulate matter in the Dagu River in the wet and dry seasons were quite different. The surface suspended particulate matter in the wet season had a negative δ13C (–29.1‰) and a low POC/PN (6.3), and its organic matter mainly came from river phytoplankton; the surface suspended particulate matter in the dry season had a more positive δ13C (–26.8‰) and a higher POC/PN (8.8), and its organic matter were derived from river phytoplankton as well as from C3and C4plants brought in by riverine erosion of the soil, and the source of organic matter in surface sediments were more complicated, in addition to river phytoplankton, the contribution of C3 plants, C4 plants, marine phytoplankton, and sewage source were also mixed. The relative contribution of the terrestrial organic matter in river sediments based on the two-end member model of δ13C decreases from 58% to 0% from upstream to downstream. Principal component analysis showed that the presence of dissolved inorganic nitrogen (DIN) led to phytoplankton blooms in the river corresponding to high levels of POC, chlorophyll-a and short-chain alkanes. The sediments in the estuarine section could absorb more organic matters due to fine grain size and large specific surface area, thus resulting higher TOC content than that in the riverine section. Comparison of the TOC loading in riverine and estuarine sediments showed that the organic matters underwent resuspension during transportation, and the longer oxygen exposure time resulted in the microbial decomposition of about 85% of the terrestrial organic matter into CO2. The results of this study provide data support and references for understanding the source and conservation characteristics of organic matters in small and medium-sized rivers.
2024 Vol. 44 (7): 3919-3930 [Abstract] ( 127 ) [HTML 1KB] [ PDF 1619KB] ( 1099 )
3931 Spatiotemporal evolution of vegetation coverage in Beijing-Tianjin-Hebei and its response to natural anthropogenic changes
CHEN Shu-qi, HE Ling, YAN Feng
This study investigated the spatiotemporal changes of vegetation cover in Beijing-Tianjin-Hebei region using Sen trend analysis, Mann Kendall significance test and Hurst index analysis, in which FVC was synthesized using the maximum value of the like element dichotomous model based on the normalized difference vegetation index (NDVI) data from 2001 to 2020. In addition, this study also quantified the relative contribution rate of impact factors using meteorological factor data, correlation analysis and residual analysis. The results indicated that the vegetation construction in Beijing-Tianjin-Hebei region was good in the past 20 years. The average coverage was 64.5% in the whole region, and the vegetation change rate varied from -0.0597421/a to 0.039797/a. However, the vegetation cover fluctuated greatly, which showed obvious geographical differences. The spatiotemporal variation of FVC in this region can be affected by a multitude of factors. The distribution of FVC was negatively correlated with temperature, and its distribution area was close to the geographical boundaries, which was related to the urban heat island effect. Conversely, the FVC showed a positive correlation with precipitation, and its distribution followed ecological zones, predominantly regulated by geographical factors. The average residual error of human activities was -0.00105, mainly exhibiting negative impact. Furthermore, the relative contribution rates of natural factors and human factors were 31.33% and 68.67%, respectively. This revealed that human activities were the major driver of vegetation change. Although a positive trend is expected, a decrease in FVC is also predicted in urban areas. This study can guide the FVC monitoring at the junction of Beijing, Tianjin and Hebei, carry out positive human intervention, enhance the environmental quality of Beijing-Tianjin-Hebei, and boost the high-quality development of the regional ecological environment.
2024 Vol. 44 (7): 3931-3944 [Abstract] ( 109 ) [HTML 1KB] [ PDF 6581KB] ( 1105 )
3945 Occurrence, spatial distribution, and risk assessment of novel brominated flame retardants in sediments from black-odorous rivers
HUANG Chen-chen, ZENG Yan-hong, GUAN Ke-lan, LIU Yin-e, LU Qi-hong, WANG Shan-quan, LUO Xiao-jun, MAI Bi-xian
In the current study, the pollution characteristics of six novel brominated flame retardants (NBFRs) in sediments from 173 black-odorous urban rivers in 74 Chinese cities were comprehensively investigated. The results indicated that decabromodiphenyl ethane (DBDPE) was the predominant NBFR, with a concentration range of undetected-603.76ng/g dry weight and an average proportion of (99.49±0.82)%. However, the concentration proportions of hexabromobenzene (HBB) and pentabromotoluene (PBT) were very low. These concentration compositions of NBFRs in sediments were consistent with their production and use history in China. Although the concentrations of DBDPE, HBB, and PBT showed significant differences among various sampling cities, they generally followed similar distribution patterns, with higher concentrations in eastern regions (South, East, and Northeast China) and lower concentrations in western regions (Northwest and Southwest China). These distribution patterns of NBFRs were strongly associated with the industrial structure and urbanization of each city. Besides, the concentrations of DBDPE, the alternative of Deca-BDEs (BDE209), were generally lower than those of BDE209 in sediments. The concentration ratios of DBDPE to BDE209 were generally significantly negatively correlated with the gross domestic product and local industrial output. The results of ecological risk assessment suggested that DBDPE, HBB, and PBT in black-odorous urban river sediments had no risk to aquatic biota.
2024 Vol. 44 (7): 3945-3954 [Abstract] ( 134 ) [HTML 1KB] [ PDF 1919KB] ( 1005 )
3955 The influence of soil physics and chemical properties on groundwater nitrogen pollution in the riparian zone of Shaying River
LI Bao-ling, YANG Li-hu, SONG Xian-fang, QIN Ming-zhou
Taking the typical section of Shaying River as the research object, we collected river water, soil and groundwater samples from riparian zones and analyzed the physicochemical indexes, aiming to deeply explore the impact mechanism of soil physical and chemical properties on groundwater nitrogen concentration in the riparian zones. The results showed that the total nitrogen (TN) content in farmland riparian soils is higher than that of the riparian zone of orchards, indicating a 1.15 times higher TN content. The TN contents of the riparian soils were highest at about 200m from the river bank. There is a certain response relationship between groundwater and soil nitrogen content in the riparian zone, showing similar spatial distribution characteristics. Groundwater NO3--N concentrations in the riparian zone of agricultural fields (0.56~25.17mg/L) were significantly higher than those in the riparian zone of orchards (0~0.97mg/L); groundwater NO3--N concentrations in the far bank (>200m) were significantly higher than those in the near bank (<100m). Soil nitrogen is one of the main sources of nitrogen pollution in riparian groundwater. The high content of clay particles in the soil and the amount of nitrogen application make the soil particles more likely to adsorb NO3--N. It increases the risk of nitrogen pollution in riparian groundwater. This study reveals the influence mechanism of soil physical and chemical properties on groundwater nitrogen content in the riparian zones. It provides a reference for the prevention and control of groundwater nitrogen pollution in locally. These findings could help develop feasible land management strategies to slow or prevent the further spread of groundwater nitrogen contamination.
2024 Vol. 44 (7): 3955-3965 [Abstract] ( 161 ) [HTML 1KB] [ PDF 2553KB] ( 1194 )
3966 Occurrence characteristics and ecological risk assessment of microplastics in surface seawater of nearshore mariculture area in Rushan
LIANG Hui, TANG Yan-li, YU Meng-jie, YANG Pei-qi, YANG Ming-da
A mariculture area near the shore of Rushan city was taken an example to establish an efficient assessment of ecological risk of the microplastics based on the abundance and composition of in-situ microplastics in the surface water, which were detected by the stereomicroscopy and laser direct infrared techniques, and evaluated by the specie sensitivity distribution model. The results in present study showed that the microplastics with those characteristics of blue/transparent, fiber, and the size less than 500 μm were predominant. The averaged abundance of the microplastics were (1.08±0.41) n/L ranging from 0.42 to 1.72n/L. Among various types of polymers, the chlorinated polyisoprene (CPI), polyurethane (PU), polyamide (PA), and polyethylene terephthalate (PET) were most common. The no-effect concentration of non-spherical microplastics (fiber and fragment) in the seawater was estimated as 4.47n/L with the toxicity data and specie sensitivity distribution model. It revealed that the risk of microplastic pollution in the investigated mariculture area was significantly lower than that of the hazard warning abundance, but the plastics with high chemical toxicity flowing into the sea was urgently needed to be avoided.
2024 Vol. 44 (7): 3966-3975 [Abstract] ( 136 ) [HTML 1KB] [ PDF 1599KB] ( 985 )
3976 Predicting the water ecological criteria of copper using machine learning and multiple linear regression approaches
YANG Xiao-ling, WANG Meng-xiao, LI Xiao-juan, YUAN Ya-wen, SHAO Mei-chen, MU Yun-song, BAI Ying-chen, WU Feng-chang
In this research, copper and representative aquatic organisms in China were investigated as a case study. Based on the theoretical framework of the biotic ligand model (BLM), the key environmental factors (hardness, pH and dissolved organic carbon) were screened by a gradient boosting decision tree algorithm, and multivariate coupled predictive models were established for predicting acute toxicities of different aquatic organisms. And then, the species sensitivity distribution (SSD) analysis was performed to predict the WQC of copper for protecting aquatic organisms, which was suitable for the characteristics of water environment in China. It was found that the prediction accuracy (RFx, 2.0) of a three-variable model based on aquatic toxicity data of 3phylum and 5families was 42% higher than that of the BLM. The SSD curves for the nine organisms were best fitted using a sigmoidal-logistic model (0.922<R2<0.991, 0.0267<RMSE<0.0767, P>0.05), and the threshold of short-term water ecological criteria of copper is recommended as 0.07350~15.38µg/L in the river basin of China. Based on the feature importance analysis from machine learning, the key role of DOC in the formulation of WQC for metals was quantitatively identified, and it also provided direct evidence for intensively treating multiple environmental factors. Compared with existing technologies including the BLM, our finding makes a beneficial attempt to develop an "in situ" WQC predictive model to meet water environment characteristics and management needs in China. It will reduce the costs for environmental monitoring and management, and enhance the regionalization and precision of water environment management.
2024 Vol. 44 (7): 3976-3985 [Abstract] ( 155 ) [HTML 1KB] [ PDF 1010KB] ( 1390 )
3986 Research on the impact of land use/cover change on carbon storage in the southern mountain area of Jinan
WANG Yi-bing, LI Cheng-liang, ZHANG Peng, HOU Lei, LIU Zhong-qiu, LIU Jing-qiang, QIU Qing-tai, ZHAO Chen-rui
The study focused on the ecologically vulnerable area in the lower reaches of the Yellow River-the southern mountainous region of Jinan. Based on land use/cover data from 1980 to 2020, this research utilized the InVEST model (Integrated Valuation of Ecosystem Services and Trade-offs model) to analyze the spatial-temporal distribution characteristics and dynamic changes of land use/cover and carbon storage in the region. The aim was to investigate the impact of land use/cover changes on terrestrial ecosystem carbon storage. The results showed that land use/cover change has a significant impact on carbon storage. During the period from 1980 to 2005, the carbon storage of forest and grassland exhibited significant accumulation due to minimal land use change and limited human activities, resulting in a notably higher growth rate of carbon storage compared to other time periods. The urban expansion rate was the fastest, and the urban and rural construction land occupied a large number of cultivated land, forest land and grassland from 2005 to 2010, which significantly reduced the regional carbon sequestration capacity. The urban expansion in the southern mountainous area of Jinan was the fastest and the urban and rural construction land occupied a large amount of cultivated land, forest land and grassland from 2005 to 2010, which significantly reduced the regional carbon sequestration capacity. The regional carbon storage was expected to gradually increase from 2010 to 2020, owing to the constraints on urbanization expansion and the implementation of ecological protection measures such as afforestation. The total carbon storage in the southern mountain area of Jinan exhibited a pattern of "increase, decrease, and subsequent increase" from 1980 to 2020. Moreover, The forest land emerged as the primary contributor to carbon storage in this region. Furthermore, the value of regional carbon storage demonstrated an upward trend with increasing distance from urban and rural residential centers, indicating significant influence of human activities on regional carbon storage. In addition, the change of land carbon density caused by the transfer of land use type is the main influencing factor of regional carbon stock change, and the change of land use type carbon stock has a certain relationship with the area change of different regions. The results can provide a theoretical basis for establishing a good terrestrial carbon sink pattern in ecologically fragile areas.
2024 Vol. 44 (7): 3986-3998 [Abstract] ( 136 ) [HTML 1KB] [ PDF 4635KB] ( 1147 )
3999 Study on the risk zoning of secondary sudden water pollution caused by geological disasters in the upper reaches of the Yangtze River
ZHOU Xia-fei, ZHOU Sheng-sen, XU Xiang-yu, Xie Ming-li, XU Ze-sheng, CAO Guo-zhi, WANG Kun-peng
This study proposed a risk assessment framework of "geological hazards-risk sources-transmission pathways-sensitive receptors" and conducted a zoning assessment of secondary sudden water pollution risks from geological disasters in the upper reaches of the Yangtze River. The risk field assessment method was employed in this work and a 1km×1km grid is the basic unit. A set of data was utilized and processed by the authors, including geological disaster hidden danger points Survey data, environmental statistics data, DEM data and water quality monitoring section data. The results show that: ① The high-risk area is 22,534.1km2, accounting for 2.3% of the total area; 105,239.1km2 and 10.7%, 857, 694.4km2 and 87.0% for medium-risk and low-risk areas separately. ② From the perspective of spatial distribution, high-risk areas are mainly located in Chongqing, the southeastern part of Longnan, the central part of Mianyang, the northern part of Nanchong, the southeastern part of Aba Prefecture, the southern part of Ya'an, the central part of Liangshan Prefecture, and the western part of Deyang. ③ In terms of the spatial distribution along key riverbanks, the high-risk areas are mainly distributed along the Chongqing section of the Yangtze River, the Panzhihua section of the Jinsha River, the Longnan and Nanchong sections of the Jialing River, the Chengdu and Aba sections of the Min River, and the Liangshan Prefecture section of the YaLung River.
2024 Vol. 44 (7): 3999-4008 [Abstract] ( 157 ) [HTML 1KB] [ PDF 2625KB] ( 907 )
4009 Exploration of the adsorption/desorption behavior and influencing factors of norfloxacin in sediments in the upper reaches of the Yellow River
ZHANG Xiao-zhen, HE Rui, LIU Zhe-wei, WU Jia-li, DIAO Jing-ru, HUANG Kui, JIANG Yu-feng
Norfloxacin (NOR) was selected as the target pollutant, and the sediment in the upper reaches of the Yellow River was taken as the main research object. The adsorption/desorption behavior of NOR on the sediment was studied by using the batch balance method. The adsorption/desorption rule was explored under different environmental conditions (initial concentration, ionic strength and type, pH value, particle size, etc.) to explore the adsorption mechanism. The results show that the kinetics is consistent with the quasi-second-order kinetic model (R2>0.996), indicating that the adsorption and desorption processes are complex mechanisms controlled by multiple actions, and the desorption has obvious hysteresis. The thermodynamic results showed that the Freundlich model had the best fitting result (R2>0.981), followed by the Linear model (R2>0.937), indicating that the multimolecular layer adsorption and hydrophobic distribution on heterogeneous surfaces both affected the key mechanism of NOR adsorption behavior on sediments, and the temperature increase accelerated the migration risk of NOR in the water phase. With the increase of NOR initial concentration, the adsorption capacity increases and the equilibrium time prolongates accordingly. The pH showed that acidity promoted NOR adsorption, and the migration risk increased under alkaline condition. The effect of coexisting soluble ions on NOR adsorption results showed that the larger the concentration of the same ions, the stronger the adsorption inhibition of NOR on the sediment. The influence of different coexisting ions on adsorption is mainly related to the characteristics of coexisting ions, such as ion radius, cation exchange capacity and hydrolysis, etc. The higher the valence state, the stronger the inhibition effect. The smaller the particle size, the larger the adsorption capacity. The results of this study will provide scientific basis for controlling the environmental behavior of antibiotic pollutants in the upper reaches of the Yellow River.
2024 Vol. 44 (7): 4009-4020 [Abstract] ( 126 ) [HTML 1KB] [ PDF 1048KB] ( 1042 )
4021 Multi-scenario simulation of “production-livelihood-ecological” space in Urumqi based on PLUS
ZHOU Man-yi, WANG Cheng-wu
Based on the land use data of Urumqi in 2000, 2010 and 2020, this paper uses PLUS model to select 15 driving factors including social economy and natural environment to simulate the space changes of "production-livelihood-ecology" in Urumqi in 2030 under four scenarios,development of production, living standard, ecological protection and comprehensive optimization.The results show that from 2000 to 2020, the grassland area continuously decreased, shrinking by 614.06km2. The cultivated land first slightly increased and then significantly decreased, totaling a decrease of 226.39km2 .The area of other land types showed a trend of continuous increase.the change degree of grassland and unused land is the most dramatic. From the results of multi-scenario simulation, in the four scenarios, the living space area shows an expanding trend, and the maximum expansion degree reaches 85.86km2, under the scenarios of development of production and living standard, the area of production space expands by 3.13km2 and 38.17km2 respectively, while the area of ecological space shrinks by 30.11km2 and 124.03km2 respectively, under the scenario of ecological protection and comprehensive optimization, the area of production space shrinking and the maximum shrink degree reaches 149.8km2, the spatial change trend of land use type under the comprehensive optimization scenario is similar to the simulation result of ecological protection scenario, but the difference is that the change trend of the former is relatively moderate. Altogether, the simulation results under the comprehensive optimization scenario are more in line with the requirements of urban development and ecological protection. Urumqi City must seize the opportunity, solve the contradiction between urban development and ecological protection in time, so that it can embark on a sustainable development path.
2024 Vol. 44 (7): 4021-4030 [Abstract] ( 163 ) [HTML 1KB] [ PDF 1838KB] ( 935 )
4031 Evolution of landscape ecological risk and its response to natural and anthropogenic factors: A case study of ecological conservation area in Beijing
GAO Lin, ZHAO Zhong-qiu, SONG Dong-yang, PEI Xiao-long
This study utilized land use/cover data from 1990 to 2020 and established a model for evaluating landscape ecological risks. It explored the spatiotemporal characteristics of landscape ecological risks in the ecological conservation area of Beijing over the past 30 years. Additionally, the study employed a geographic detector model to investigate the roles of natural and anthropogenic factors in driving landscape ecological risks. The results indicate that from 1990 to 2020, the primary land use types in the study area were forests and arable land. There was a trend of increasing forested areas, built-up land, and water bodies, while arable land, grassland, and unused land decreased. The average value of landscape ecological risks continuously decreased, with low and relatively low ecological risk areas increasing by 2124.34, 1247.96km2, respectively. Meanwhile, areas with moderate, relatively high, and high ecological risks decreased by 8.45%, 13.66%, and 8.13%, demonstrating a positive correlation at the spatial scale. In single-factor detection, anthropogenic disturbance, NDVI, and elevation were identified as the main factors driving changes in landscape ecological risks. Results from two-factor interaction detection consistently showed enhanced interactions and nonlinear enhancements, with anthropogenic disturbance interacting with other factors being the primary cause of the evolution of landscape ecological risks. This study reveals the changes in land use patterns and landscape ecological risks in the ecological conservation area of Beijing over the past 30 years. It investigates the driving factors behind the evolution of landscape ecological risks, providing a scientific basis for maintaining ecological stability and promoting green development in Beijing's ecological conservation area.
2024 Vol. 44 (7): 4031-4041 [Abstract] ( 110 ) [HTML 1KB] [ PDF 2771KB] ( 1259 )
4042 Analysis of priority control sources of heavy metal pollution in sediments of the lower of Daqing River Basin
YUAN Ru-yu, ZHANG Qi, LI Cheng, WU Yi-hong, TIAN Zai-feng
In order to explore the impacts of different pollution sources of heavy metals on ecology and human health risk, this paper took the lower of Daqing River Basin as the research object, collected and measured the contents of heavy metals Cu, Pb, Ni and Cr in 36sediment samples, quantified the degree of heavy metal pollution by using the traditional analytical method, analyzed the sources of heavy metal pollution in the sediment by utilizing the Positive Definite Matrix Factor Analysis (PMF). Meanwhile, on the basis of PMF source analysis, combined with heavy metal toxicity and environmental background values, the contribution of pollution sources to ecological and human health risks was quantitatively analyzed by using PMF combined with the potential ecological risk index model (ERI) and human health risk assessment model (HHRA). The results of the single-factor pollution index showed that the four heavy metals Pb, Ni, Cu and Cr were slightly polluted in the study area, using the background value of soil heavy metals in Hebei Province as the standard value. The PMF analysis showed that the sources of heavy metal pollution were industrial sources (43.26%) > agricultural-transportation sources (34.97%) > transportation-natural sources (21.77%). The PMF-ERI showed that traffic-natural sources (39.21%)>Agriculture-transportation sources (34.07%)>Industrial sources (26.72%), and traffic-natural sources were the best control sources of potential ecological risks. The PMF-HHRA showed that industrial sources (43.98%)>Agriculture-transportation source (26.90%)>Traffic-natural sources (29.12%) and industrial sources were the best-controlled sources of human health risks, and Cr was the best control pollutant for human health risks.
2024 Vol. 44 (7): 4042-4052 [Abstract] ( 108 ) [HTML 1KB] [ PDF 2172KB] ( 1371 )
Environmental Microbiology
4053 A review of microbial mercury methylation in domestic waste landfills
PENG Xu-ya, YANG Yan, DING Li-hu, AN Yu-wei, SONG Li-yan, LI Lei, YANG Shu
The management of methylmercury pollution within landfill environments is currently a hot topic in the field of environmental science. This manuscript endeavors to assimilate and scrutinize the corpus of extant research pertaining to mercury contamination and its methylation processes within landfill contexts. The spatial disposition of mercury and methylmercury within landfills is analyzed, and material balance calculations are performed for mercury in landfills. Furthermore, this study delineates the principal microbial taxa implicated in landfill mercury methylation and elucidates the underlying mechanisms thereof. Concurrently, an investigation about the factors influencing microbial mercury methylation is conducted, leveraging the unique biochemical properties inherent to landfill ecosystems. Building upon this foundation, future research directions for methylmercury in landfills are outlined, providing new insights for the risk management and control of mercury pollution in landfills. Existing studies have mainly focused on the characterization of total mercury and methylmercury levels in landfill waste and leachate, distribution characteristics, and their correlation with environmental factors. However, there is limited research on the microbial diversity responsible for mercury methylation and its dominant methylation mechanisms in landfills. To further control the risk of methylmercury pollution in landfills, it is necessary to address both mechanistic research and engineering practices. By elucidating the mechanisms of microbial mercury methylation in landfills, preventive and inhibitory measures can be implemented effectively.
2024 Vol. 44 (7): 4053-4062 [Abstract] ( 117 ) [HTML 1KB] [ PDF 574KB] ( 959 )
4063 Effects of low temperature on the growth, metabolism, and quorum sensing of heterotrophic nitrifying bacteria Acinetobacter sp
WANG Yi-shu, LI Yuan, HOU Lian-gang, CHEN Hui-xuan, HOU Hui-min, WANG Xiu-jie
To further explore the mechanism of nitrogen transformation and quorum sensing system of HN-AD bacteria under low temperature, there were at least three AHLs signaling molecules, including C6-, C8-, and C10-HSL produced by the HN-AD bacterium JQ1004 based on the analysis of GC-MS. The concentration of AHLs showed a significant density dependence and continuously accumulated with the increase of biomass. When the temperature decreased from the optimal 30℃ to 10℃, C6- and C8-HSL showed a continuous decreasing trend due to the decrease of cell concentration, while the concentration of C10-HSL increased first and then decreased, reaching a maximum value of 10.89nmol/L at 20℃, indicating that C10-HSL played a crucial role in the bacterial adaptation to low-temperature environments. Further study found that adding 10nmol/L C10-HSL at low temperature could significantly shorten the bacterial lag period and improved the nitrogen removal rate. The addition of C10-HSL at 20℃ and 10℃ increased the expression of amoA by 35% and 22%, respectively, while the expression of napA increased by 14% and 9.4%. C10-HSL enhanced the ability of quorum sensing of strains by increasing the receptor protein activity regulated by luxR. Adding C10-HSL at low temperature could promote extracellular protein secretion, reduce polysaccharide content, improve biofilm activity, and strengthen its adaptability to harsh low-temperature environments.
2024 Vol. 44 (7): 4063-4070 [Abstract] ( 102 ) [HTML 1KB] [ PDF 663KB] ( 609 )
Ecology Toxicology
4071 Effects of several key hydrochemical factors on toxicity of typical heavy metals to aquatic organisms
WANG Xin, GAMA Zha-xi, SHI Wen-qing, CHENG Ying-hao, XU Zi-han, GUO Wei, WANG Ying
In order to clarify the effects of different hydrochemical conditions on the toxicity of heavy metals to aquatic organisms, this study investigated the influence of four primary hydrochemical factors, i.e., pH, hardness, temperature, and organic carbon (OC), on the acute and chronic toxicity of four typical heavy metals to different taxon of aquatic organisms. The results showed the effects of individual hydrochemical factors on the toxicity of different metals differ. The increases in hardness and OC were found to reduce the toxicity of metals to fish, whereas the increase in temperature enhanced the toxicity to both fish and insects. The impact of individual hydrochemical factors varied for different taxon of organisms. When considering the combined effects of these factors, the effects of acute toxicity and chronic toxicity to aquatic organisms were significantly different. OC might be an important factor affecting toxicity.
2024 Vol. 44 (7): 4071-4083 [Abstract] ( 159 ) [HTML 1KB] [ PDF 3428KB] ( 455 )
Beautilful China Initiative: Environmental Economy
4084 Discussion on the development direction of environmental economics discipline in China under the background of building a beautiful China initiative
PANG-Jun, LIANG-Yu-chao, QIN-Hai-xiang
Environmental economics is a branch of economics that studies the interrelationship between economic development and environmental protection. In the era of comprehensively building a Beautiful China, the development of environmental economics faces new opportunities and challenges. This article analyzes the main development directions of environmental economics in China under the background of building a Beautiful China. Firstly, it briefly describes the background of the birth and development of environmental economics as well as the development process of environmental economics in China. Secondly, it summarizes the main research areas of environmental economics, including design and evaluation of environmental economic policy, cost-benefit analysis, environmental valuation, and climate change economics. Next, it elaborates on how environmental economics can respond to important tasks in the construction of Beautiful China from various perspectives. Finally, it is argued that the discipline of environmental economics in China can innovate from multiple perspectives such as environmental policy and institutions, green finance, pollution and health, ecological product valuation and realization, climate adaptation, and international cooperation, thereby contributing to the construction of a Beautiful China.
2024 Vol. 44 (7): 4084-4090 [Abstract] ( 159 ) [HTML 1KB] [ PDF 341KB] ( 1077 )
Carbon Emission Control
4091 Life cycle assessment and carbon reduction scenario analysis of retired lithium iron phosphate batteries for cascade utilization
DOU Yong-qi, SONG Xiao-long, ZHUANG Xu-ning, WU Wen-jie, FAN Shuai-kang
The paper takes lithium iron phosphate batteries as research object, by considering the proportion of cascade utilization, life cycle and battery capacity, different cascade utilization scenarios are set, then the environmental impact of retired power batteries in the cascade utilization and subsequent disposal is quantified by using life cycle assessment method, and the carbon emission reduction under different cascade utilization rate scenarios is analyzed. The results indicate that compared to direct recycling, the three cascade utilization scenarios of energy storage, communication base stations and low-speed power supply all show environmental benefits. Among them, the energy storage scenario has the greatest environmental benefits, showing relative advantages in environmental impact indicators such as climate change, fossil energy consumption, human toxicity-non carcinogenic and terrestrial ecotoxicity. Based on the retirement amount of battery retirement and the direction of cascade utilization, the paper further calculates the carbon reduction for the cascade utilization of lithium iron phosphate batteries in 2023 is 1.05×108kg CO2eq. When the cascade utilization rate remains at the current level or increases by 10%, the annual carbon reduction in 2023 can reach 1.55×109kg CO2eq. and 5.98×109kg CO2eq. The cascade utilization has good performance in reducing pollution and carbon emissions.
2024 Vol. 44 (7): 4091-4100 [Abstract] ( 149 ) [HTML 1KB] [ PDF 957KB] ( 1205 )
4101 Research hotspots and trends of the health effects of synergistic emission reduction of greenhouse gases and air pollutants
GUO Ya-li, JIA Jun-song, HE Shan
CiteSpace was used to sort out the relevant literature on Web of Science and China National Knowledge Infrastructure, and analyze the research hot spots and progress in this field. The findings revealed that, first the number of published works had been steadily increasing both domestically and internationally. Particularly, after 2013, the number of published articles has been growing rapidly, with a significantly higher rate observed in international publications compared with domestic ones. Second, a robust collaborative network was established by foreign literature authors and institutions, primarily centered around major universities in the United States. The number of core research authors who had published articles in this network has reached 39%. Conversely, it appeared that the relationship between domestic authors and institutions was weaker, exhibiting a decentralized structure with multiple centers. The publications of core research authors accounted for only 8% of all domestic literature works. Third, The strong synchronicity between domestic and foreign research was indicated by the results of the visual analysis, focusing mainly on studying the health effects and burden of disease caused by environmental exposure. However, specific impact mechanisms, linkages, and risk assessment were more emphasized by foreign researches. On the other hand, influencing factors and policy benefits were paid closer attention to by domestic researches. Fourth, ranging from studying the impact of environmental exposure on health endpoints to investigating climate change co-adaptation strategies and developing complex models, foreign researches centered more on global burden and decrease of particulate matter emissions. On the other hand, Domestic researches had evolved from studying the effects of climate change and air pollution on health to exploring coordinated governance countermeasures and health risks. Currently, there was considerable interest in the potential synergistic benefits of climate change, pollution reduction, and carbon reduction on health. In the future, the identification and clarification of the spatiotemporal patterns of health issues and sensitive areas, as well as public health effects caused by climate change and air pollution will be a key focus. The construction of health risk assessment models and the development and application of early warning systems should also be put on top agenda.
2024 Vol. 44 (7): 4101-4116 [Abstract] ( 120 ) [HTML 1KB] [ PDF 4826KB] ( 1195 )
4117 Accounting and driving factors analysis of energy carbon emissions in Heilongjiang Province
LIU Hao-dong, QIU Wei, CHEN Shuang
Based on the method of the Intergovernmental Panel on Climate Change, it calculated the carbon emissions of energy consumption in Heilongjiang Province from 2005 to 2020. By using the Logarithmic Mean Divisia Index (LMDI) decomposition model and the STIRPAT model, it analyzed the relationship between energy carbon emissions and driving factors such as the economy and population in depth. Scenario simulations were conducted to explore reasonable paths for the future development of Heilongjiang Province. According to the results of the LMDI factor decomposition, the economic level factor had the greatest cumulative effect on energy carbon emissions. Through the STIRPAT model and scenario simulation analysis, the comprehensive scenario was identified as the optimal scenario among the four scenarios. Finally, based on the "dual carbon" goal and research results, it provided the suggestions for relevant regulatory strategies.
2024 Vol. 44 (7): 4117-4126 [Abstract] ( 119 ) [HTML 1KB] [ PDF 1222KB] ( 1088 )
Emerging Contaminants
4127 Characteristics of microplastics in outdoor artificial rubberized/turf sports fields
WANG Xi, SUN Jiao-xia, ZHENG Han-yue, XIANG Xin, XU De-mei, XIANG Xing-yu, FAN Jian-xin
In this study, we conducted an investigation into the characteristics of microplastics found on the surface and in the rainfall runoff of various sports fields(plastic running tracks、artificial turf、basketball courts、badminton courts and tennis courts). The findings revealed that the abundance of surface microplastics ranged from 32500 to 120120 item/dm2, while the abundance of microplastics in rainfall runoff ranged from 8.26×106 to 4.08×107 item/L. The distribution of microplastics abundance in both surface samples and rainfall runoff exhibited a similar pattern, with artificial turf having the highest abundance, followed by plastic running tracks, basketball courts, badminton courts, and tennis courts. Microplastics smaller than 0.5mm constituted over 97% of the total. The primary plastic types identified in all sports fields included polyurethane (PU), polyethylene (PE), organosilicon-modified polyurethane (silicone PU), and rubber particles, with fragments and fibers being the main forms. Furthermore, all sports fields displayed indications of microplastic aging as a result of long-term usage. A clear correlation was observed between the quantity and types of microplastics present in the rainfall runoff and the characteristics of microplastics found on the surface. This implies that a significant amount of microplastics generated on the surface of sports fields can be carried by rainfall runoff and contaminate surface water. Therefore, it is essential to assess the environmental risks associated with the release of microplastics from outdoor artificial rubberized/turf sports fields. Implementing appropriate retention measures becomes imperative in order to prevent the infiltration of microplastics into surface runoff.
2024 Vol. 44 (7): 4127-4135 [Abstract] ( 129 ) [HTML 1KB] [ PDF 1827KB] ( 765 )
4136 Distribution and source characterization of microplastics pollution in Zhengzhou Section of the Yellow River
LI He-tong, MA Zhen-fang, GUO Yu, DENG Zheng-yun, LI Yin-yue, GUI Xin, MA Li, ZHANG Fa-wen
To investigate the distribution and pollution characteristics of microplastics in the water environment of the middle and lower reaches of the Yellow River in China, this study took the Zhengzhou section of the Yellow River as the study object, selected seven representative points for water sample collection, observed the abundance and morphological characteristics of microplastics by body-viewing microscope, further identified their constituents with the help of micro-infrared spectroscopy, compared and analyzed the statistics with the microplastic pollution status of other water bodies, and explored their pollution sources. The results showed that the average abundance of microplastics in the water body was (16.86 ±4.20) n/L; the size of particle less than 1mm was dominant, accounting for 61.42%; the shape of fibrous accounted for the highest proportion of 79.31%; the color of microplastics was dominated by transparent, accounting for 56.06%; Rayon dominated the polymer type of microplastics, and there were also polyethylene terephthalate (PET) and polypropylene (PP), etc. The morphological characteristics and polymer types of microplastics in different locations can reflect their potential sources of pollution to a certain extent. Compared with other water bodies, the abundance distribution of microplastics in Zhengzhou section of the Yellow River showed some differences, while the distribution trend of particle size was more or less the same, and the shape and color were mainly fibrous and transparent. The differences in microplastic contamination among different water bodies may be closely related to the habitat around the water bodies, the economic level, and the situation of human activities.
2024 Vol. 44 (7): 4136-4144 [Abstract] ( 137 ) [HTML 1KB] [ PDF 2186KB] ( 1062 )
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