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  Current Issue
 
2023 Vol.43 Issue.4,Published 2023-04-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Microbiology
Environmental Ecology
Environmental Impact Assessment and Management
Environmental Toxicology and Health
Carbon Emission Control
Air Pollution Control
1489 The contrast study of the characteristics of PM2.5 explosive growth at urban and rural stations in Beijing from 2016 to 2020
YOU Yuan, ZHANG Bi-hui, LI Si-teng, JIANG Qi, AN Lin-chang
The difference of pollution characteristics between urban and rural stations in Beijing from 2016 to 2020 was analysed using PM2.5 concentration, meteorological observational data, NCEP and ECMWF reanalysis dataset. Explosive growth processes were defined based on multiple threshold metrics, focusing on the analysis of atmospheric circulation and different sources of pollutants in the process of explosive growth. The results showed that the number of air pollution days had decreased year by year, while the proportion of pollution days in autumn and winter decreased from 2016 to 2017. In addition, the proportion of pollution days increased from 2018 to 2020. The pollution improvement at urban stations was slower than that at rural stations. The duration of pollution were generally less than or equal to 3d from 2016 to 2020. The number of air pollution days at urban stations were more than that at rural stations when the duration of pollution were more or equal to 2d, and the frequency of air pollution days had decreased year by year. There were obvious mutual influence characteristics of fine particulate pollution at urban stations and rural stations, and the impact of urban stations on rural stations was more significant. The number of explosive growth and the proportion of explosive pollution at urban stations and rural stations first decreased and then increased. The number of explosive growth process at urban stations was more than that at rural stations, however, the proportion of explosive pollution in urban areas was lower than that in suburbs. Most of the explosive growth processes occurred under types of uniform pressure field, such as the front of high pressure, zonal circulation and behind trough (the frequency of explosive growth were ≥10%).The transmission during explosive growth processes at urban station occurred most frequently under the weather type of behind trough and the front of high pressure, with an occurrence frequency of 37.0%. The transmission during explosive growth processes at rural station occurred most frequently under the weather type of zonal circulation and the front of high pressure, with an occurrence frequency of 31.6%. The local explosive growth at urban and rural stations occured most frequently under the weather type of zonal circulation and uniform pressure field, with the exceeding ratio of 34.5% and 56.5% respectively.
2023 Vol. 43 (4): 1489-1498 [Abstract] ( 269 ) [HTML 1KB] [ PDF 779KB] ( 1659 )
1499 Estimation of the column concentration of carbon dioxide using spaceborne shortwave infrared spectrometer
LI Jing-bo, ZHANG Ying, GAI Rong-li
In this paper we used OCO-2 satellite observations, TCCON (total carbon column observing network, TCCON) observations, NDVI (Normalized Difference Vegetation Index) records, and atmospheric parameters from ERA5, and apply various machine learning models including decision tree and ensemble learning (e.g. XGBoost, random forest, extreme random forest, gradient lifting) to predict the carbon dioxide column concentration. Models are established to predict the concentration of carbon dioxide column through correlation analysis, feature selection and extraction. Model prediction results are then compared with the data from XCO2 observations from TCCON. By comparing the prediction results from different models, it has been found that the extreme random forest regression model has the best performance in predicting CO2 column concentration. R2, RMSE (root mean square error), MAE (mean absolute error) and MRE (mean relative error) of Extra Trees Regressor (extreme random forest regression model) are 0.953, 0.492×10-6, 0.260×10-6 and 0.063% respectively. Thereafter, the prediction performance of ExtraTreesRegressor is analysed by changing the input parameters. The results show that within the acceptable error range (±2x10-6), the prediction accuracy of extreme random forest regression model and gradient lifting regression model is the same, which is 98.10%. Because the variation range of CO2 column concentration is small, it is necessary to further narrow the error range. Within the error range of ±1×10-6, the prediction accuracy of extreme random forest regression model and gradient lifting regression model are 91.82% and 90.51% respectively. Therefore, the extreme random forest algorithm results in better accuracy in predicting CO2 column concentration, which meets the accuracy requirements of CO2 prediction.
2023 Vol. 43 (4): 1499-1509 [Abstract] ( 305 ) [HTML 1KB] [ PDF 2725KB] ( 1681 )
1510 The role of fog on the PM2.5 based on multi-source data and numerical model
MENG Li-hong, YANG Er-hui, CAI Zi-ying, HAO Jian, YANG Jian-bo
In order to explore the impact mechanism of fog on the PM2.5 concentration during the process of the fog-haze, the multi-source observation data such as automatic meteorological station data, environmental hourly concentration data, microwave radiation data, wind profile radar, aerosol lidar, 255m meteorological tower data and WRF-Chem process analysis method were used to analyze the role of advection-radiation fog on the PM2.5 in Tianjin from January 24 to 27, 2021. The results show that: The increasing in relative humidity during fog formation phase is attributed to the radiative cooling and advection, indicating that the fog type is advection-radiation fog. The water vapor was transported from top to down during the formation of fog. The fog-top height was 250m, and the bottom of the inversion layer height was 80~120m, so the fog-top height was higher than inversion layer bottom height during the process of the fog. Because the role of the relative humidity、vertical advection and turbulent mixing before fog formation, the PM2.5 mass concentration of the ground and vertical direction was growth first then slowed again, and the overall benefit of PM2.5 mass concentration was diffusion. According to the inversion layer bottom height, there were two situations of the role of fog on the PM2.5 during the fog mature period. One was removing PM2.5 when the fog height was higher than the bottom height of inversion. The other was scavenging PM2.5 When the fog height was lower than the bottom height of inversion. The turbulent kinetic energy was active after fog dissipation, turbulent mixing amount of contribution -40~-23μg/(m3·h), fog was conducive to the ground PM2.5 mass concentration diffusion.
2023 Vol. 43 (4): 1510-1518 [Abstract] ( 233 ) [HTML 1KB] [ PDF 2070KB] ( 757 )
1519 CFD simulation of spray absorption of ammonia-based desulfurization based on gas-liquid mass transfer
YANG Guo-hua, WU Di, GOU Yuan-Bo, XU Bing, CHEN Ya-fen, ZHANG Ming, JIA Yong
Combining with the research of SO2 mass transfer in the process of ammonia-based desulfurization, the CFD calculation method which could calculate the SO2 removal efficiency was developed with the CFD secondary development technique by coupling the multi-component chemical reaction in the ammonia desulfurization droplet, the mass transfer between the droplet and the gas phase (double membrane theory), and the droplet evaporation phase change. The three-dimensional model was established based on this method could calculate the flue gas flow rate, pH value, liquid-to-gas ratio, atomized particle size, and initial SO2 concentration on the desulfurization effect. The results show that the simulation results and the experimental data have the similar tendency varying with the operational factor and the relative error between the two is less than ±20%. By calculating the influence of key parameters such as pH value and slurry particle size on the distribution of NH3 and SO2 concentration on the vertical centerline in the desulfurization tower, the pH and particle size of the slurry can be controlled to improve the desulfurization efficiency and reduce the NH3 escape. The experimental and numerical simulations results show that the recommended flue gas flow rate is 2~3m/s, the slurry pH value is 5~6, gas-liquid ratio is 2.5~3.5L/m3 and the atomized particle size is 0.8~1mm for the ammonia desulfurization system.
2023 Vol. 43 (4): 1519-1527 [Abstract] ( 265 ) [HTML 1KB] [ PDF 2107KB] ( 1117 )
1528 Pollution characteristics, key toxic components and sources of PM2.5-bound heavy metals in coking polluted area of Jiexiu, Shanxi
LI Hong-yan, ZHAO Zhi-xin, HE Qiu-sheng, FU Guo, LI Hong-yu, BAI Jing-ai, HUANG Shi-dan, ZHANG Yan-ru, YUN Yang, CUI Yang, WANG Zhen-tao
On the basis of analyzing pollution characteristics of 11kinds of heavy metal elements in atmospheric PM2.5 samples from Jiexiu coking area (JX) and Fangshan control area (FS), the key toxic components that potentially threaten human health and their sources were identified using positive definite matrix factor (PMF) source apportionment, health risk assessment and in vitro cytotoxicity test. The results showed that the concentrations of PM2.5 and its loaded heavy metals in JX exceeded the ambient air quality standards seriously, and exhibited seasonal variation following the sequence of winter > autumn > summer > spring. The total non-carcinogenic and carcinogenic risks of all elements in JX were 2.80 and 2.10 times that of FS, respectively. Except that the annual average concentration of element Cr in JX was lower than that of FS, the concentrations of elements Pb, Cd, Zn, As, Mn, and Sb in JX were 15.9, 9.80, 9.00, 7.40, 7.00 and 4.20 times that of FS, respectively. Among them, Mn, As, Cd, Pb had high non-carcinogenic risks, while Pb also had high carcinogenic risk. Among the 5 major sources of PM2.5-bound heavy metals in JX, coal combustion and coking contributed the most (37.7%), followed by other industrial sources (29.6%), iron and steel smelting sources (20.4%). Coal combustion and coking contributed as high as 38.8% and 44.9% to non-carcinogenic and carcinogenic risks, respectively, and they were the only ones that had a significant positive correlation with cellular oxidative stress and toxicological indicators related to the inflammatory reaction (ROS, TNF-α and IL-1β). Except for As, the carcinogenic and non-carcinogenic levels of other heavy metal elements were within acceptable range, and coal combustion contributed the most to health risks and cytotoxicity.
2023 Vol. 43 (4): 1528-1538 [Abstract] ( 278 ) [HTML 1KB] [ PDF 1884KB] ( 1685 )
1539 Spatiotemporal differentiation of ozone pollution in Chinese cities and meteorological correlation among the identified hot urban agglomeration during 2018 to 2020
LI Fei, KONG Shao-jie, QU Zhi-guang, YAN Jing-jing, GUO Jin-yuan, ZHOU Yuan-yuan, OU Chang-hong
Based on the daily maximum 8h moving average surface ozone (O3-8h) from 2018 to 2020, spatial autocorrelation analysis, exposure risk assessment and multiple linear regression analysis were used to study the spatiotemporal differentiation of O3 and population-weighted O3 exposure risk characteristics in Chinese 337 cities. The hot urban agglomerations were identified and the meteorological correlation characteristics of O3 were analyzed in the hot urban agglomerations. The results showed that O3 had significant spatial aggregation, with a concentration higher than 160μg/m3 (GB3095-2012), an exceedence rate higher than 20%, and the regions with high population-weighted exposure risk level were mainly concentrated in Beijing-Tianjin-Hebei Urban Agglomeration (BTH-UA), Central Plains Urban Agglomeration (CP-UA) and Yangtze River Delta Urban Agglomeration (YRD-UA). Secondly, the monthly O3-8h change in 2018~2020 showed “M” distribution, the highest value appeared in June, September and May, respectively. Monthly average ρ(PM2.5), ρ(NO2), ρ(SO2) and ρ(CO-95) showed “W” distribution, and reached the peak in December and January. Linearly fitting straight-line coefficients (R2) for monthly average ρ(PM2.5), ρ(NO2), ρ(SO2) and ρ(CO-95) with O3-8h were 0.68, 0.52, 0.38 and 0.66, respectively. Finally, the association of meteorological factors in the hot urban agglomerations was analyzed based on multiple statistical method. The results showed that O3-8h were strongly associated with average daily temperature (T), sunshine duration (S) and daily precipitation (R), and a weak correlation with average daily relative humidity (RH), average daily pressure (p) and average daily wind speed (v), indicated that the main meteorological factors were T, S and R in the three urban agglomerations. Moreover, the higher T and S, the lower RH, p, v and R, the more favorable O3 concentration and the influence of different meteorological factors on O3-8h reflected the characteristics of “An urban agglomeration is a feature”.
2023 Vol. 43 (4): 1539-1549 [Abstract] ( 298 ) [HTML 1KB] [ PDF 1943KB] ( 1994 )
1550 PM and TVOC emission characteristics and emission factors of typical general aviation aircraft
HAN Bo, SHI Yi-lin, JI Xiang, PAN Li-li, XIAO Zhi-mei
The DA-40D was selected as a typical model, and the test and analysis of particulate matter (PM), black carbon (BC) and total volatile organic compounds (TVOC) under five working conditions with thrust power of 13%, 37%, 52%, 73% and 100% were carried out at Chaoyang Airport in Liaoning Province on December 5~8, 2019. The results showed that the peak concentrations of PM particles under the five thrust powers were at 0.25 and 0.3μm in the high thrust condition, while the peak value in the small thrust case was not obvious, and the PM1/PM10 reached more than 99%. The mass concentrations of PM2.5, BC and TVOC emissions of this engine showed an increasing trend with the increase of thrust, and the concentrations were 129.8~1039.4, 18.3~291.9 and 311.6~7343.2μg/m3, respectively, and the emission concentrations increased rapidly in the full thrust, medium/full thrust and medium thrust ranges, respectively. Through the stepwise regression method, it is found that the total inlet pressure of the engine has the greatest influence on PM2.5 and BC concentration, while the TVOC concentration is mainly affected by the coolant temperature. By constructing the aircraft LTO flight model, combined with the emission intensity fitting and aircraft performance parameter calculation, the emission factors of PM2.5, BC and TVOC in the LTO process were determined to be 25.91, 6.98 and 71.26μg/LTO, respectively, and the contribution of pollutant emissions in the climbing stage accounted for the largest proportion. The research results provide a basis for exploring the pollutant emission characteristics of general aviation aircraft and promoting pollution prevention and control in airports and surrounding areas.
2023 Vol. 43 (4): 1550-1557 [Abstract] ( 287 ) [HTML 1KB] [ PDF 687KB] ( 1479 )
1558 The optimization of surface acidity VPO/TiO2 catalyst and its low-temperature NH3-SCR denitration performance
CHEN Yi-hua, WANG Pan, MENG Fan-yu, CHEN Ya-fen, ZHANG Ming, JIA Yong
HCl was used to modify the surface acidity of supported vanadium phosphorus oxide (VPO/TiO2) catalysts for NH3-SCR. The results show that the denitration activity of catalyst was the highest with HCl/V molar ratio of 3~5:1, and the efficiency was almost 100% when the reaction temperature reached 200℃. It was found that the addition of HCl improved the crystallinity of the catalyst, and the modification of HCl could slightly increase the specific surface area of the VPO/TiO2 catalyst. Meanwhile, the amount of active component V4+ in the VPO/TiO2 catalyst was gradually increased from 38% to 46%, which improved the redox performance of the catalyst. In addition, the relative content of chemisorbed oxygen in the catalysts with different HCl/V molar ratios increased with the increase of HCl addition amount. The pyridine infrared test results show that HCl affected the acid site of the catalyst, and the catalyst with HCl/V molar ratio=5 had the highest Lewis acid content as 0.84×10-4mol/g. Data fitting results further demonstrate that the low-temperature denitration activities of all VPO/TiO2 catalysts were positively correlated with the amount of weak Lewis acid (correlation coefficient > 0.9), which is consistent with the results of activity test.
2023 Vol. 43 (4): 1558-1566 [Abstract] ( 271 ) [HTML 1KB] [ PDF 1714KB] ( 1299 )
1567 Effects of pure biodiesel blended with PODE on combustion and particulate matter emissions of a marine diesel engine
WEI Li-jiang, GAO Yu-fei, DAI Ming-cheng, HUANG Wen-qing, LU Xiu-wei, SHI Hao-tian, LIU Su-bo
In this paper, D100 (pure diesel), B100 (pure biodiesel) and B90P10 (pure biodiesel and PODE (polyoxymethylene dimethyl ether) blended at a volume ratio of 9:1) were tested on a marine diesel engine. The combustion process and particulate matter emission of the three fuels were experimentally studied. The results show that, compared with D100, the maximum in-cylinder pressures of B100 and B90P10gradually increased, and the crank angles corresponding to the maximum in-cylinder combustion pressures were sequentially advanced. At low load, the peak pressure rise rate, peak heat release rate and the initial combustion temperature of B100 and B90P10 were significantly increased compared with D100. The soot of marine diesel engine can be greatly reduced by B100, and the blending of PODE can further reduce soot emission. At high load and low load, the particle emission factors of B90P10 were 11.80 and 17.77mg/(kW·h), respectively, which were 64.21% and 76.34% lower than those of D100. The total amount of particulate matter emitted by B100 and B90P10 was significantly higher than that of D100, and the increased particles were mainly in the nuclear mode of small particle size.
2023 Vol. 43 (4): 1567-1573 [Abstract] ( 237 ) [HTML 1KB] [ PDF 549KB] ( 965 )
1574 Effect of Ni modification on NH3-SCR denitrification performance of rare earth tailings
HOU Li-min, Lü Bing-yu, FU Shan-cong, WU Wen-fei
Ni modified rare earth tailings catalysts with different proportions were prepared by hydrothermal method. The effects of Ni modification on the catalyst performance were analyzed by XRD, BET, H2-TPR, NH3-TPD and XPS characterization methods.The results show that Ni modification could significantly increase the NOx conversion rate of rare earth tailings catalyst. The NOx conversion rate of 6%Ni/ rare earth tailings catalyst reached 85% at 300℃, the selectivity of N2 was over 76% in the temperature range from 250℃ to 300℃. After modification, NiFe2O4 with good dispersibility was generated in the catalyst, The specific surface area increased to 75.12m2/g, the acidic sites of the catalyst increase, which is conducive to the adsorption of more ammonia on the catalyst surface, the Ni ions act as electron transporters, converting Fe2+ into Fe3+, the chemical valence of Fe increases, the instability of the outermost electrons of iron increases, the oxidation capacity increases, the enhanced oxidation capacity is conducive to the activation of ammonia adsorbed species on the catalyst surface and the denitrification reaction.
2023 Vol. 43 (4): 1574-1581 [Abstract] ( 198 ) [HTML 1KB] [ PDF 1045KB] ( 705 )
Water Pollution Control
1582 In situ biological activity and N2O production characteristics inside Anammox granular sludge
Lü Yong-tao, WANG Chong-yang, JU Kai, HOU Tong-jie, PAN Yong-bao, WANG Lei
The concentrations of ammonium, nitrite, nitrate and N2O were determined inside Anammox granules using microelectrodes, and the relationship between in situ biological activity and N2O production was established. The results showed that the Anammox activity with simultaneous consumption of ammonium and nitrite was distributed in the surface layer of the granule (0~1500μm), with the maximum activity at 200~400μm. When the concentration of ammoonium was 14mg/L (c(NH4+):c(NO2-)=1:1.2), the maximum ammonium and nitrite consumption rates were 1.19 and 1.65mg/cm3/h, respectively. The denitrifying activity was mainly distributed in the deep layer of 1500 to 2500 μm. When nitrite or nitrate was used as the only substrate ((NOx--N=14mg/L), the maximum N2O production rates were 0.37 and 0.19 mg/(cm3×h), respectively. N2O was mainly produced in the deep layer of the granule, and the production rate increased 28.16 times with the decrease of pH from 8.5 to 7.0, reaching 0.35mg/(cm3×h). Anammox bacteria (Candidatus Kuenenia), denitrifying bacteria (Truepera, Limnobacter, Ignavibacterium and Anaerolineaceae) and ammonia oxidizing bacteria (Nitrosomonas) were also detected by high-throughput sequencing. In conclusion, Anammox activity was mainly distributed in the surface layer, while N2O was mainly generated in the deep denitrifying active layer. Therefore, N2O was mainly produced by denitrifying bacteria.
2023 Vol. 43 (4): 1582-1589 [Abstract] ( 252 ) [HTML 1KB] [ PDF 1301KB] ( 913 )
1590 Low-frequency ultrasound assisted electrocatalytic degradation of antimicrobial fluconazole in water
LIU Zhun, MENG Xin-xin, QIAN Xu-bin, TANG Shao-yu, FANG Cheng, XU Lei, NIU Jun-feng
Low-frequency ultrasound (20kHz, 78W) assisted electrochemical oxidation (Ti/SnO2-Sb/La-PbO2 as the anode) was used to eliminate aqueous fluconazole, and the degradation mechanism was further investigated. Fluconazole cannot be directly degraded by low-frequency ultrasound. The acceleration electrochemical degradation of fluconazole might be ascribed to the increased ·OH electrochemical production (81.95 times) under low-frequency ultrasound. Moreover, the mass transfer rate and the electron transfer ability at the electrode interface were also enhanced, which were conducive to the electrochemical degradation of fluconazole. The reaction rate constants of fluconazole degradation increased by 42.68% when the ultrasound power increased from 26W to 130W, and increased by 24.00 times when the current density increased from 2mA/cm2 to 20mA/cm2. The main degradation mechanism of fluconazole was the indirect oxidation of ·OH (relative contribution of 82.45%~85.71%). Fluconazole was degraded by defluorination, bond cleavage, cyclization and oxidation, followed by the formation of formic acid, oxalic acid, NO3- and F-.
2023 Vol. 43 (4): 1590-1600 [Abstract] ( 225 ) [HTML 1KB] [ PDF 1380KB] ( 1589 )
1601 Research progress of analytical methods for composition and structure of protein and polysaccharide in sludge
JIN Yi-wei, PING Qian, LI Yong-mei
With the growing amount of sludge, sludge resource recovery is getting more and more attention. Anaerobic digestion is one of the most common technologies for sludge treatment. Nowadays, research about the enhancement of sludge digestion keeps growing rapidly, while the research about the influence of organic matters in sludge on the anaerobic digestion mechanism is still developing. This review introduces the influence of dominating organic matters in sludge, protein and polysaccharide, on anaerobic digestion, and summarizes the main methods analyzing the content and structure of protein and polysaccharide in sludge. The analytical methods for advanced structure of protein and polysaccharide are still in its infancy, which become one of the limiting factors to study the mechanism of organic matter transformation during anaerobic digestion, and require further exploration in future.
2023 Vol. 43 (4): 1601-1609 [Abstract] ( 433 ) [HTML 1KB] [ PDF 1101KB] ( 2175 )
1610 Characterization of molecular transformation and bioavailability of dissolved organic nitrogen in the A/A/O process
HAN Cheng-long, ZHAO Ling-yun, DUAN Bing, CUI Xian, LIU Cai-feng, HU Hai-dong, REN Hong-qiang
The concentration distribution, molecular transformation, and bioavailability characteristics of DON along the anaerobic/anoxic/oxic (A2/O) process were investigated by various methods. The results showed that the concentration of DON decreased from (5.3±0.3)mg/L in the influent to (2.0±0.1)mg/L and (1.8±0.2)mg/L along the anaerobic and anoxic tanks respectively. Interestingly, the concentration of DON in the oxic unit increased to (1.9±0.1)mg/L, and the removal rate was (-5.6±0.6)%. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis of the molecular composition of DON showed that the proportion of active DON molecules (H/C≥1.5) in each unit was: anaerobic unit (38%)
2023 Vol. 43 (4): 1610-1619 [Abstract] ( 253 ) [HTML 1KB] [ PDF 1494KB] ( 1096 )
1620 Insights into the performance of sulfidated zero-valent iron toward molybdenum removal
NIU Meng-fan, ZHANG Xue-ying, CAI Zu-ming, WU Hao-ran, QIAO Jun-lian, SUN Yuan-kui
Nowadays, molybdenum (Mo) pollution in natural waters has become an increasing threat to human beings and microorganisms. Although zero-valent iron (ZVI) is considered to be an environmentally friendly approach for effective Mo(VI) sequestration, the low reactivity of traditional ZVI particles largely limits the ZVI application in real practice. To address this issue, sulfidated ZVI (S-ZVIbm) was prepared by a ball-milling method and its performance toward Mo(VI) removal was systematically evaluated in this work. Results showed that the sulfidation treatment could greatly accelerate the ZVI corrosion in the presence of oxygen, and thereby markedly improve both the rate and capacity of Mo(VI) removal by ZVI. In specific, the observed rate constants (kobs) of Mo(VI) removal by S-ZVIbm were determined to be 0.059~0.866h–1 at initial pH 6.0, which were 3.6~42.3 folds higher than that of unmodified ZVI. Likewise, the Mo(VI) removal capacity was increased from 9.86 to 31.9mg/g upon sulfidation. Collectively, it was found that the sulfidation treatment could eliminate the passivating impact of Mo(VI) on ZVI corrosion and thus enable the S-ZVIbm particles to sequestrate Mo(VI) effectively. Mechanically, X-ray absorption fine structure spectroscopy revealed that Mo(VI) was mainly sequestrated via chemical adsorption rather than via reduction. Moreover, it was found that sulfidation amendment did not alter the Mo(VI) removal pathway by ZVI, despite it can improve the Mo(VI) removal efficiency greatly. These findings could provide some insights into the application of S-ZVIbm in metal(loid)s-contaminated water treatment.
2023 Vol. 43 (4): 1620-1627 [Abstract] ( 248 ) [HTML 1KB] [ PDF 1262KB] ( 1255 )
1628 Effect of phosphomolybdic acid pretreatment at different initial pH on acid production from waste activated sludge in anaerobic fermentation
JIANG Tan, WANG Bo, LI Xiao-di, MA Yu-qing
Phosphomolybdic acid, a green and strong oxidant, can not only promote the hydrolysis in the process of anaerobic fermentation of waste activated sludge (WAS), but also inhibit the methanogenic microorganisms effectively, but the specific role of phosphomolybdic acid along with pH adjustment on the production of volatile fatty acids (VFAs) is still unknown. This study proposed a method to optimize the anaerobic fermentation of WAS by controlling the initial pH (7, 8, 9, 10) and phosphomolybdic acid. Results showed that increasing the initial pH and dosing phosphomolybdic acid were beneficial to the release of organic matter from WAS, which promoted the production of volatile fatty acids (VFAs). Especially when the initial pH was 10, the maximum VFAs production (1588.7mg COD/L) was 2.0 times that of the unregulated initial pH (778.1mg COD/L), and the proportion of acetic acid reached 48.7%. Therefore, phosphomolybdic acid and alkaline condition played a synergistic effect on the anaerobic fermentation process, for which the production of VFAs could be increased.
2023 Vol. 43 (4): 1628-1635 [Abstract] ( 222 ) [HTML 1KB] [ PDF 1155KB] ( 810 )
1636 Performance of iron scrap to alleviate the inhibition of sulfides on denitrification by anaerobic ammoxidation
CHEN Jie, WANG Cai-xia, WANG Qian, SHEN Yao-liang, LIU Wen-ru
The long-term inhibition of sulfide on anaerobic ammonia oxidation (Anammox) system and the effect of adding scrap iron on the system performance were studied in an up-flow anaerobic sludge bed reactor (UASB). Results showed that low concentration (<10mg/L) of sulfide had no significant effect on the system performance. When its concentration increased to 20, 30 and 40mg/L, the nitrogen removal rate (NRR) of the reactor decreased by 13%, 42% and 51%, respectively. The high concentration (40mg/L) of sulfide reduced the specific anaerobic ammonia oxidation activity (SAA) by 63%. Anammox biomass had adaptability to the sulfide inhibition. Moreover, the long-term operation with sulfides caused the deterioration of particle structure, sludge floating, and caking. The addition of iron scrap significantly alleviated the inhibition of sulfide, and quickly recovered the sludge settleability and the reactor nitrogen removal efficiency. After 19 days of iron scrap addition, the NRR increased by 20% (up to 4.43kg/(m3·d)) compared with the sulfur-free stage, and the SAA reduced only by 16.8%. The microbial community analysis showed that the increased sulfide concentrations caused the decrease of the relative abundance of Candidatus Kuenenia from 18.81% to 7.31%. The relative abundance of Candidatus Kuenenia at the bottom layer of the reactor was 15 times higher than that at the top layer after adaptation. At the same time, the denitrifying bacteria (Arenimonas and Thiobacillus) were enriched. After adding scrap iron, the abundance of Ca. Kuenenia decreased slightly, but the relative abundance of Ca. Kuenenia at the top layer was higher than that at the bottom layer. The relative abundance of Thiobacillus in the system increased by 3.36 times, and the relative abundance of denitrifying bacteria in the bottom layer also increased. This study provides a new idea for promoting the application of Anammox process in sulfide containing wastewater.
2023 Vol. 43 (4): 1636-1645 [Abstract] ( 256 ) [HTML 1KB] [ PDF 1759KB] ( 1161 )
1646 Comparative study of different proposal distribution MCMC algorithms in groundwater pollution source identification
LI Xue-li, LUO Jian-nan, LIU Yong
In order to obtain the optimal proposal distribution by exploring the influences of normal distribution, uniform distribution and random walk of the MCMC algorithms on the inversion identification results of groundwater pollution source, this paper established a simulation model of pollutant transport and a surrogate model using Kriging method with a hypothetical case, and the MCMC algorithm based on normal distribution, uniform distribution and random walk was developed to identify the release history of groundwater pollution sources. The results show that the inversion algorithm with uniform distribution as the proposal distribution has the advantages of high inversion accuracy, good stability and fast convergence speed, which proves to be the most suitable proposal distribution for groundwater pollution sources inversion.
2023 Vol. 43 (4): 1646-1654 [Abstract] ( 294 ) [HTML 1KB] [ PDF 1200KB] ( 1594 )
1655 Defluorination of coal chemical wastewater and nitrogen and phosphorus removal performance of tailwater
ZHANG Guang-rui, REN Bin, LI Hai-song
The multi-step defluorination process was used to optimize the dosing sequence and dosage control cost in order to reduce the concentration of F- in water to below 1mg/L. High-throughput sequencing of the 16S rRNA gene was used to examine the microbial community structure after nitrogen and phosphorus were removed from the defluorination tailwater. Based on the optimized defluorination scheme, F- concentration could decline from 119.73~138.56mg/L to 0.33mg/L with the defluorination cost of 6.13yuan/t. The nitrification and denitrification loads of defluorination tailwater reached to 0.12 and 0.13kg/(m3·d), respectively. The nitrification process achieved stable shortcut nitrification from the eighth batch with an average nitrite accumulation rate (NAR) >80%. This was due to the early free ammonia (FA) and late free nitrite (FNA) inhibitions. Denitrifying phosphorus removal was seen during the denitrification process, and the phosphorus absorption rate ranged from 84.10% to 89.75%. The result of high-throughput sequencing demonstrated the great change of microbial community structure had a great shift after 20 batches of domestication. The abundance of aerobic denitrifying bacteria (Paracoccus and Pseudomonas), heterotrophic denitrifying bacteria (Flavobacterium and Thauera), and denitrifying phosphorus accumulating bacteria (Paracoccus, Pseudomonas and Thauera) were enriched in acclimation sludge.
2023 Vol. 43 (4): 1655-1662 [Abstract] ( 202 ) [HTML 1KB] [ PDF 559KB] ( 1248 )
1663 Removal of Cd2+ from water by fly ash-based mesoporous aluminum-incorporated tobermorite
XU Lin-hao, ZHENG Bo-ying, YANG Long-sheng, WU Dai-she, WANG Ze-hua
Mesoporous aluminum-incorporated tobermorite (TFA) with different Al/Si molar ratios were hydrothermally synthesized from fly ash (FA). The physicochemical properties of FA and TFA were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Field emission environment scanning electron microscope (SEM), Specific surface aperture analyzer, and Fourier transform infrared spectroscopy (FTIR). It was found that the specific surface area, pore volume and average pore size of TFA1 (Ai/Si=0.4) were 74.30m2/g, 0.4495cm3/g and 24.20nm, respectively, while those of TFA2 (Ai/Si=0.1) were 99.48m2/g, 0.5218cm3/g and 20.98nm, respectively. They were much higher than those of FA (1.77m2/g, 0.004338cm3/g and 9.79nm). The adsorption kinetics data of FA, TFA1 and TFA2 for Cd2+ were more consistent with the pseudo-second-order kinetics model. The Langmuir isotherm model provided better description of the Cd2+ adsorption isotherm, and the maximum adsorption capacity for Cd2+ on TFA1 was 205.76mg/g, which was much higher than those on FA and TFA2 (94.58mg/g and 107.30mg/g). The removal mechanism of Cd2+ on TFA were analyzed by XRD, SEM-X-ray energy dispersive spectrometer and FTIR. The results show that the mesoporous structure of TFA, a large amount of -OH, the ion exchange of Ca2+ and Cd2+, and the precipitation of CdCO3 and Cd(OH)2 played important roles in removing Cd2+. This work shows that the TFA can be used as an efficient and inexpensive adsorbent for Cd2+, which provides a potential application method for resource utilization of FA and the treatment of wastewater containing Cd2+ and other heavy metal ions.
2023 Vol. 43 (4): 1663-1671 [Abstract] ( 206 ) [HTML 1KB] [ PDF 1334KB] ( 982 )
1672 Removal of Rhodamine B from aqueous solutions by magnetic biochar activated persulfate
XIANGLI Peng, CUI Jia-li, ZHANG Feng, LI Hong-yan, CUI Jian-guo, WEI Liu-yi
The magnetic CoFe2O4/biochar (MPBC) derived from pine needles was prepared by a sol-gel method. The structure and surface physical-chemical properties of as-prepared MPBC was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), specific surface area analyzer (BET), X-ray photoelectron spectrometer (XPS) and vibrating sample magnetometer (VSM). The MPBC was used to activate peroxynitrite (PS) for Rhodamine B (RhB) removal. The results showed that under the optimal conditions of initial RhB concentration of 40mg/L, initial pH value of 5, temperature of 25℃, MPBC dosage of 8.0g/L and PS dosage of 0.05mol/L, the removal rate of RhB reached 98.8% after 120min. The removal rate of RhB tended to increase with the increasing of MPBC dosage and initial RhB concentration, and was effective in a wide range of pH value from 3 to 11. Humic acid, NO3-, HCO3- and Cl- inhibited the removal efficiency of RhB. Free radical quenching experiments and electron paramagnetic resonance (EPR) tests exhibited that the active species including SO4·-, ·OH, 1O2 and ·O2- played a dominating role in the MPBC-PS system. The saturation magnetization intensity of MPBC measured by VSM was 23.41 emu/g, indicating that it was easy to be magnetically recovered. After 5 cycles of reuse, the RhB removal rate still reached 95.4%, showing good stability.
2023 Vol. 43 (4): 1672-1687 [Abstract] ( 246 ) [HTML 1KB] [ PDF 3540KB] ( 1732 )
1688 The influence and health risk assessment of groundwater quality in irrigated area
XU Li-wen, BIAN Jian-min, SUN Xiao-qing, LOU Yu-qi, SUN Guo-jing
In order to explore the influence of drainage in irrigated areas on regional groundwater quality and health risks, the groundwater monitoring data of different strata in the western region of Jilin from 2012 to 2014 and 2019~2020 were selected, and the random forest method was used to evaluate the groundwater quality, and the spatio-temporal variation of groundwater quality under the influence of irrigated areas was analyzed. The primary environmental background of the study area and the influence of the irrigation area were comprehensively considered, and the health risk assessment of multiple elements exceeding the standard of groundwater was integrated. The spatio-temporal variation and influencing factors of the superimposed double risks were systematically compared and analyzed. The results show that the chemical types of groundwater in the irrigated area and its surrounding areas are mainly HCO3--Na+-Ca2+ weakly alkaline water, and there is no significant change in the two periods. Groundwater exceeding the standard consists of F, Fe, Mn and "trinitrogen" compounds. Drainage in irrigated area aggravates the change of "trinitrogen" content in surrounding water. There was a 17% increase in category Ⅳ to Ⅴ water in shallow groundwater, and a 12% increase in the number of monitoring sites with health risks exceeding the safety threshold. The health risks of groundwater are caused by the superposition of NO3-, NO2-, NH4+ in the retreated water of irrigated area and the health risks caused by F and Mn in the native environment. NO3-, NO2- and NH4+ are the main control factors of health risk in shallow groundwater. Confined water is insensitive to the disturbance of water retreat in irrigated area.
2023 Vol. 43 (4): 1688-1695 [Abstract] ( 279 ) [HTML 1KB] [ PDF 2189KB] ( 817 )
1696 Effects of biochar on sewage disposal and microbial community structure in multi-soil-layering system
ZHENG Shi-jie, ZHANG Jian-qiang, HE Yang, YANG Song-lin, JIANG Mei, TAO Yi
To further improve the efficiency of multi-soil-layering (MSL) systems, the effects of biochar on the removal mechanism were investigated through the comparison of typical pollutant removal efficiencies and microbial community structure in MSLs with different shaped soil modules(square and U-shaped). The results showed that biochar could significantly improve the average removal rate of pollutants in MSLs (P<0.05) under different hydraulic loads, exhibiting fast start-up and shock load resistance. The average removal rates were 87.74%, 96.23%, 97.65% and 89.38% for CODCr, TP, NH3-N and TN. The U-shaped structure could improve the average removal rates of CODCr, TP, NH3-N, and TN, which was not significantly different from the square structure (P>0.05)(except TP). Biochar enhanced the removal of ammonia nitrogen by increasing the relative abundance of ammonia-oxidizing bacteria and denitrifying bacteria, and the denitrification became more smooth with a higher relative abundance of nitrite-oxidizing bacteria in U-shaped MSL system. Therefore, biochar enhanced the efficiencies and stability by regulating the structural characteristics of microbial communities and the waterflow in MSL systems.
2023 Vol. 43 (4): 1696-1705 [Abstract] ( 300 ) [HTML 1KB] [ PDF 1239KB] ( 1433 )
1706 PMS oxidation catalyzed by modified ceramic membrane for the treatment of secondary effluent
ZHU Ye, ZHU Xiu-rong, JIN Xin, LI Ke-qian, LIU Meng-wen, WANG Gen, JIN Peng-kang, WANG Xiao-chang
In order to obtain high removal efficiency of dissolved organic matter from secondary effluent of wastewater treatment plant, two kinds of highly efficient permeable non-destructive catalytic ceramic membranes (N-C-CM, Fe/N-C-CM) made of carbon-based catalysts (N-C, Fe/N-C) were designed in this study, the in situ activated PMS filtration system using composite catalytic membrane was established, and the optimal operational conditions of composite catalytic membrane were also investigated. The results showed that at the optimal operational conditions (catalyst loading 0.15g, PMS dosage 15 mmol/L and pH 9), the removal efficiency of TOC, color and UV254in secondary effluent were 62.83%, 81.42% and 56.62%, turbidity is 0.00 NTU, respectively using Fe/N-C-CM activated PMS filtration system, which was generally higher than PMS direct oxidation combined with the original ceramic membrane (VCM) filtration and N-C-CM in situ activated PMS filtration system. By comparing the membrane specific flux, membrane fouling resistance distribution and membrane flux recovery rate of the three ceramic membranes after filtration of secondary effluent under the same conditions with or without PMS, it was further confirmed that Fe/N-C-CM in situ activated PMS filtration system can reduce the concentration of pollutants on the membrane surface, thus effectively alleviate membrane fouling. EPR analysis further proved that Fe/N-C-CM in situ activated PMS filtration system produced more SO4-·, ·OH and 1O2 than PMS direct oxidation combined with VCM filtration and N-C-CM in situ activated PMS filtration system.
2023 Vol. 43 (4): 1706-1715 [Abstract] ( 241 ) [HTML 1KB] [ PDF 2283KB] ( 1106 )
1716 Effect of temperature on sludge bulking in aerobic granular sludge system
OU Jia-li, GAO Chun-di, HAN Ying-lu, YANG Xiao-yang, CHENG Li-yang, PENG Yong-zhen
To explore the effects of temperature on sludge bulking and the characteristics of microbial community structure in aerobic granular sludge system, three sequencing batch reactors were used with artificial wastewater as the influent. Illumina sequencing technology was used to analyze the microbial community structure and dynamic changes of bacteria in aerobic granular sludge system at 10℃,18℃ and 25℃,respectively.The results showed that the particle sludge settling performance of the 18℃ was good, and the SVI maintained at about 40mL/g. But under the conditions of 10℃ and 25℃, aerobic granular sludge were bulked, of which the SVI were 194.67mL/g and 100mL/g, respectively. According to the qPCR analysis, at 10℃, the abundance value of Sphaerotilus Natans was the highest among the specific filamentous bacteria, it mass propagation of this bacterium would leaded to extremely high SVI. Illumina sequencing results showed that temperature caused the significant differences of dominant species among these three systems. The predominant strains at 18℃ were Tsukamurella and unclassified_f_Comamonadaceae, this system had a good pollutant removal ability. And at 10℃, the predominant species was Sphaerotilus, which was unable to utilize complex organic matter. As for the system at 25℃, the dominant bacteria were Tsukamurella and unclassified_f_Microbacteriacea. To analyze the nitrogen removal performance of aerobic granular sludge system from the micro point of view, the FAPROTAX database was used to predict the differences in bacterial metabolic functions at different temperatures. At 18℃, the relative abundance of nitrate reduction and nitrate respiration bacteria, which were kinds of nitrogen cycling functional bacteria, were 7.81% and 7.78%, higher than those in other systems. This results matched the better nitrogen removal effect at the same temperatre.
2023 Vol. 43 (4): 1716-1723 [Abstract] ( 275 ) [HTML 1KB] [ PDF 1192KB] ( 942 )
1724 Effects of compound microbial agents on anaerobic treatment of food waste at low temperature
WANG Yu-chen, SU Cheng-yuan, WANG Qin, DING Feng-xiu, LIANG Zhu, WEN Shi-tong, CHEN Meng-lin, HUANG Zhi
In order to improve the efficiency of the anaerobic reactor in the low temperature environment, different volumes of compound microbial agents (0, 1, 2, 5mL) were added to the upflow anaerobic sludge bed (UASB) reactor, and the removal rates of COD and NH3-N, key enzyme activities, microbial community structure and function during the anaerobic digestion process were analyzed. The results showed that the optimum removal rates of COD (42.47%) and NH3-N (63.93%) were obtained in the UASB reactor with 2mL of compound microbial agents. And the relative activities of acetate kinase (AK) and coenzyme F420 in anaerobic sludge were increased by (120.39±4.14)% and (148.63±4.32)% compared with the control group. In addition, the abundance and diversity of microorganisms reached the highest, and the relative abundance of Proteobacteria (15.30%) and Thermotogae (1.13%) were the highest, which played an important role in organic acid production and maintaining the stability of anaerobic digestion process. Meanwhile, compared with the dominant archaea Methanobacterium (30.51%) and Methanothrix (32.80%) in the control group, the relative abundance of Methanobacterium (18.93%) was decreased by adding 2mL compound microbial agents. The relative abundance of Methanothrix (34.32%) was increased, which was favorable for the acetic acid type methanogenesis process.
2023 Vol. 43 (4): 1724-1734 [Abstract] ( 197 ) [HTML 1KB] [ PDF 2732KB] ( 874 )
1735 Achieving advanced nitrogen removal via anammox coupled with endogenous denitrification
LIU Wen-long, WANG Jia-ming, LI Jun
To achieve advanced nitrogen removal of anaerobic ammonia oxidation (anammox) process, endogenous denitrification was combined with anammox by adding sodium acetate (100mg COD/L) in the anaerobic stage of sequencing batch reactor. The nitrogen removal performance and the variations of microbial community structure in the reactor were also investigated during operation. Results showed a stable and high nitrogen removal efficiency of anammox process was achieved by coupled with endogenous denitrification. The total inorganic nitrogen (TIN) removal efficiency was increased from 79.07% ±2.63% to 97.00% ±1.35% and the effluent TIN concentration was reduced to (3.30 ±1.49)mg/L. Typical cycle data showed that the internal carbon sources such as poly-β-hydroxyalkanoates synthesized in the anaerobic stage could provide electron donors for subsequent endogenous denitrification, meanwhile the reaction rate of anammox was not affected. The nitrogen in the system, calculated by mass balance analysis, was mainly removed by anammox (PAMX:PEDN=98.27% :1.73%). Further, the sodium acetate addition stimulated the proliferation of denitrifying bacteria (i.e. Thauera) in the system. However, with the abudance increase of Denitratosoma capable of endogenous denitrifying capacity, the abundance of Anammox bacteria (i.e. Candidatus Brocadia) was restored, and therefore the advanced nitrogen removal of anammox system was realized.
2023 Vol. 43 (4): 1735-1743 [Abstract] ( 296 ) [HTML 1KB] [ PDF 1249KB] ( 1315 )
Solid Waste
1744 Effects of biomass-covering materials on gaseous emissions and mechanism during biogas slurry storage
WEI Jia-xin, QI Chuan-ren, LIU Wan-cen, LUO Wen-hai, LI Guo-xue, ZHANG Zhi-ye
This study aimed to investigate the effects of sawdust, garden waste, and corn straw as covering materials on gaseous emissions during biogas slurry storage at the same weight of 650g. The emission of ammonia (NH3), hydrogen sulfide (H2S), nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) from biogas slurry were measured by the dynamic chamber method. The results showed that mulching significantly reduced the emission of NH3, but increased the emissions of N2O, CH4, CO2 and H2S, thus increasing the total CO2 equivalent. The order of such increase followeds: garden waste (26.0%) > corn straw (24.7%) > sawdust 1(12.9%). Microbial analysis indicated that,mulching treatment inhibited the activity of microorganisms for chemoenergetic heterotrophy, anabolic heterotrophy, nitrate ammonification, nitrate reduction, nitrite respiration and nitrate respiration, thus reducing the intensity of carbon, nitrogen and sulfur cycles. Compared to garden waste and corn straw, sawdust mulching significantly reduced the relative abundance of bacteria such as Bacteroidaceae and Porphyromonadaceae to restrain carbon and nitrogen cycles for the reduction of organic decomposition and thus gaseous emissions inside biogas slurry. It is noteworthy that biomass coverage increased the cumulative emission of greenhouse gases, possibly due to the decomposition of organic substances in covering materials to overcome their performance for the blockage of gaseous emissions from biogas slurry. Of the three materials, sawdust was recalcitrant to biodegradation and thus led to lowest cumulative emission of greenhouse gases. Furthermore, sawdust facilitated the formation of a tough cake layer on the surface of biogas slurry to inhibit carbon and nitrogen cycles for gaseous emissions. Therefore, sawdust is highly recommended as the biomass material to mitigate gaseous emissions in biogas slurry storage. Nevertheless, further investigation is still needed to optimize sawdust thickness as a coverage in the management of biogas slurry storage.
2023 Vol. 43 (4): 1744-1756 [Abstract] ( 206 ) [HTML 1KB] [ PDF 806KB] ( 1193 )
1757 A synergistic promotion during anaerobic digestion of food waste generated from catering industry by the bio-abiotic additives——Biogas production efficiency and corresponding microbial dynamic changes
HU Jin-hui, MENG Wei, XIA Yi, YANG Zheng, ZHANG Xin-yu, QI Guang-xia, REN Lian-hai
The aim of this study was to solve the problem of unstable process induced by low methane production rate, "acid accumulation" and "ammonia inhibition" in the anaerobic digestion of floatable-oil recovered food waste (FORFW) generated from the catering industry. Based on our previous research that combined bio-abiotic addition could enhance the anaerobic digestion of food waste synergistically, a three factors-three levels orthogonal experiment of mesophilic anaerobic digestion was conducted in this study to investigate and optimize reaction parameters, including inoculum ratio, iron addition amount and yeast amount. The intrinsic microbial mechanism of synergistic promotion of bio-abiotic additives in FORFW methanogenesis was elucidated by the high throughput sequencing technique. It was found that the influence of three parameters on the methane yield of FORFW anaerobic digestion: inoculum ratio > yeast amount > iron addition amount. The optimal condition were inoculation ratio of 1.5, iron addition of 0.5% (w/w) and activated yeast of 3%(w/w). Under the optimal condition, the VS removal rate of FORFW was 40.1%, and the accumulative methane yield was 237.5mL/g VS. The relative abundance of genera Methanosaeta, Syntrophomonas, and Syner-01 increased significantly in the system, resulting in efficient conversion of lactic acid-derived propionic acid. Genus Methanosaeta interacted with Anaerolineaceae in syntrophic methanogenesis, Syntrophomonas was involved in butyric acid oxidation process, while Syner-01 participated in acetic acid oxidation and amino acid oxidation. Thus, the methane yield of the FORFW generated from the catering industry was ensured. The research results will provide scientific guidance for further practical application and process control.
2023 Vol. 43 (4): 1757-1764 [Abstract] ( 232 ) [HTML 1KB] [ PDF 1138KB] ( 1421 )
1765 The influencing factors of the stabilization of fresh leachate from landfill regulating ponds in cold and arid regions
SHU Yin-hui, SHAO Li-ming, DENG Ying-tao, Lü Fan, ZHANG Hua, HE Pin-jing
To develop a viable and simple method to realize the bio-stabilization of landfill leachate in cold and arid regions, this experiment chose three kinds of leachate representing those with characteristics at different landfill ages. According to a 4-factor, and 3-level orthogonal rule, the study assessed the leachate concentration (3.8, 15.4, 64.0g-COD/L), sludge inoculation quantity (1, 2, 4g VS/L), agitation frequency (0, 2, 4 times/h), and temperature (10, 20, 30℃) on four aspects relating to landfill leachate bio-stabilization in the anaerobic environment of simulated regulating ponds. The findings demonstrated that the leachate concentration and temperature were the primary determinants of bio-stabilization. The lowest concentration (3.8g-COD/L) and highest temperature (30℃) condition had the shortest bio-stabilization time (58d). Analysis of the microbial community structure of each test group revealed that the bacterial and archaeal community structure were similar in each test group at low and medium concentrations (3.8 and 15.4g-COD/L), the acetoclastic methanogenesis pathway of Methanosaeta franchise dominated the methanogenesis route; while the archaeal and bacterial communities evolved significantly during the bio-stabilization process at high concentrations (64.0g-COD/L) and 30℃, and the hydrogenotrophic methanogenic bacteria Methanofolli and Methanoculleus were gradually enriched and the abundance of the phylum Firmicutes, which is rich in the genus relating to syntrophic acetate-oxidising Bacteria, increased to more than 80%, and the anaerobic methanogenesis was dominated by the tandem pathway of syntrophic acetate oxidation and hydrogenotrophic methanogenesis. Based on the analysis of the test results, it is feasible to stabilize leachate at landfills in cold and arid regions by using regulating ponds under the condition that the capacity of regulating ponds can accommodate a half-year leachate generation.
2023 Vol. 43 (4): 1765-1772 [Abstract] ( 254 ) [HTML 1KB] [ PDF 1128KB] ( 818 )
1773 Structure-activity mechanism of electrical conductivity of sludge-based biochar
ZHANG Shan, LI Ning, HUANG Ting, SU Ming-xue
In this study, the structure-activity mechanism between the degree of aromatization, degree of defect, surface functional groups and the electrical conductivity of sludge-based biochar was explored through the regulation of preparation process parameters. The results showed that higher the degree of aromatization of sludge-based biochar, the better the π-π conjugated structure was for electron transfer and thus the stronger the conductivity. Meanwhile, contrary to the law of pure biochar, the degree of defects of biochar increased with the increase of pyrolysis temperature. Combined with XRD analysis of the composition of sludge based biochar, this law may be related to the distribution of refractory substances in sludge on the surface of biochar. When the pyrolysis temperature was 900℃ and the pyrolysis time was 30min, the resistivity of biochar prepared was only 6.834 Ω· cm, which is very close to that of pure biochar. Electrochemical tests showed that biochar prepared at low temperature (≤600℃) may mainly complete electron transfer through redox groups or metals on the surface, while biochar prepared at high temperature (>600℃) may depend on its graphitization structure to complete electron conduction.
2023 Vol. 43 (4): 1773-1781 [Abstract] ( 250 ) [HTML 1KB] [ PDF 1403KB] ( 1655 )
Soil Pollution Control
1782 Refined imaging of pH and O2 across the passivated soil-root micro-interfaces
REN Jing-hua, FAN Jian, SUN Yu, LIAO Qi-lin, XU Wei-wei, LIULing, HAN Chao, GU Xue-yuan
Herein two self-established planar optode methods (PO) were successfully deployed to in situ, high-resolution investigate the fine-scale and simultaneous variations of micro-environmental conditions e.g. pH and O2 across the passivated soil-root interfaces. For the first time, our results quantitatively and directly revealed the high degrees of spatiotemporal heterogeneity of pH and O2 throughout the rhizosphere at the sub-mm scale. Significant differences (P<0.01) among three Cd treatments were observed. The addition of the attapulgite clays significant elevated the pH micro-environemnts, but had slight effects on the micro-distributions of O2 within the soil profiles. There was a visible and distinct range of 2~5mm surrounding the rice roots where pH values were generally decreased by 0.31~0.87 and O2 concentrations were increased to 58.56~82.01μmol/L. Notably higher rhizosphere acidification and O2 leakage always occurred locally around the basal roots. The higher abilities of rhizosphere acidification and O2 leakage within the passivated soil-root micro interfaces would potentially promote the reactivation and root uptake of passivated Cd.
2023 Vol. 43 (4): 1782-1790 [Abstract] ( 292 ) [HTML 1KB] [ PDF 2422KB] ( 818 )
1791 Optimization ratio of industrial waste and sodium persulfate for synergy in solidification/stabilization of petroleum-contaminated soil
SHI Qing-hong, YANG Xiu-juan, ZHAO Zhi, FAN Heng-hui, MENG Min-qiang, MA Xing-ye
Sodium persulfate, lime, fly ash, and carbide slag were used as solidification/stabilization agent materials to investigate the influence of different materials content ratios on the unconfined compression strength, toxic leaching concentration, and acid neutralization capacity of petroleum-contaminated soil, which based on the orthogonal test included four influenced factors and four levels. The optimization ratio of solidified/stabilized materials was selected under fuzzy optimization theory frame. The changeable rules of pH value, temperature, S2O82– content and total petroleum hydrocarbon content were analyzed to explain the solidified/stabilized mechanism of petroleum-contaminated soil. The X-ray diffraction test (XRD) and scanning electron microscope (SEM) test were also conducted to illustrate the microscopic mechanism in solidification/stabilization of petroleum-contaminated soil further. The experimental results showed that the sodium persulfate content had the greatest influence on the unconfined compression strength and toxic leaching concentration of petroleum-contaminated soil based on the extremum difference analysis. And the lime content had the greatest influence on acid neutralization capacity of petroleum-contaminated soil. It also showed that the content of sodium persulfate, lime, fly ash, and carbide slag were 0.6%、8.0%、10.0%、6.0%, respectively, can be selected as the optimal ratio to solidify/stabilize the petroleum-contaminated soil according to the fuzzy optimization indexes of unconfined compression strength, toxic leaching concentration, acid neutralization capacity and handing cost. The unconfined compression strength was 630.40kPa. The toxic leaching concentration was 4.44mg/L. The acid neutralization capacity was 385.71cmol/kg. And the handing cost was 136.46yuan/t. The solidified/stabilized petroleum-contaminated soil achieved the requirement of the strength of refuse reclamation and environmental safety. The toxic leaching concentration reduction, and the strength and acid neutralization capacity improved of the solidified/stabilizes petroleum-contaminated soil. The reasons can be explained by the fact that some petroleum can be removed from the contaminated soil because of oxidated reaction between sodium persulfate and petroleum. And the cemented substance was generated to cement the soil particles due to the hydration reaction of lime, fly ash and calcium carbide slag.
2023 Vol. 43 (4): 1791-1801 [Abstract] ( 226 ) [HTML 1KB] [ PDF 2671KB] ( 987 )
Environmental Ecology
1802 Pollution characteristics of polycyclic aromatic hydrocarbons in the coral reef regions of Weizhou Island, Beibu Gulf
SHI Jing-wen, ZHANG Rui-jie, HAN Min-wei, WANG Yu-xuan, WANG Chen-yan, LI Hao-lan, KANG Ya-ru, LIU Fang, QIN Su-li, YU Ke-fu
The 15 polycyclic aromatic hydrocarbons (PAHs) that were prioritized by US EPA (excluding naphthalene) were investigated in ambient seawater, sediments, and corals from the coral reef regions (CRRs) of Weizhou Island, Beibu Gulf. The results show that these PAHs widely presented in the seawater, sediments, and corals. All of them were dominated by 3-rings PAHs (68.47%~85.62%). The total concentration of 15PAHs (∑15PAHs) was relatively higher in the seawater ((2004.49±946.22) ng/L), coral tissues ((2488.58±1375.33) ng/g), and symbiotic zooxanthellae ((2496.76±979.26) ng/g), while lower in the sediment ((61.38±37.41) ng/g). Compared with the seawater and coral tissues in October 2015, the PAHs’ levels were significantly higher in this survey. The negative relationship between ∑15PAHs and chlorophyll-a concentration ((2.14±1.92) mg/L) in coral symbiotic zooxanthellae was significant (P<0.05), indicating that the biomass dilution had a crucial effect on the ∑15PAHs in coral symbiotic zooxanthellae, i.e., the rapid propagation and growth of coral symbiotic zooxanthellae would lead to the increase in chlorophyll-a concentration and the decrease in ∑15PAHs. The most of the 3-rings and 4-rings PAHs in the seawater from Weizhou Island CRRs were already at the medium-high ecological risk to marine organisms, while fluorene (FLU), phenanthrene (PHE), and pyrene (PYR) in the sediment reached the moderate ecological risk to marine organisms. Further studies on the toxic effects of PAHs on coral symbiotic zooxanthellae are needed. Finally, the source apportionment indicates that the PAHs in the seawater were mainly from spilled oil and coal and biomass combustion, and the PAHs in sediment were mainly from spilled oil and fossil fuels combustion.
2023 Vol. 43 (4): 1802-1811 [Abstract] ( 328 ) [HTML 1KB] [ PDF 1084KB] ( 1662 )
1812 Spatial-temporal accumulation factors of heavy metals in Hunan lakes along the middle reach of the Yangtze River
KONG Ling-hui, LUO Ming-ke, YU Hui, HUA Zu-lin
To investigate the impact of economic development on the spatial-temporal distribution characteristics of heavy metals in lake sediments, lakes (≥10km2) in Hunan Province along the middle reach of the Yangtze River were collected. The sediment background values (GB) of heavy metals were analyzed by 137Cs and 210Pb radionuclide methods, geochemical background method, and multivariate statistic method. According to the results, the main toxicity risk element in Yueyang South Lake (urban area), Huanggai Lake (suburb), and Huarong East Lake (suburb) with different economic development levels were identified. Ridge regression estimation based on the STIRPAT extended model was used to investigate the spatial-temporal relationships between socio-economic indicators (total population, actual GDP per capita, urbanization rate, secondary industry ratio, tertiary industry ratio, mining and manufacturing) and the most important pollutants. The results showed that the GB of Cr, Cu, Zn, Cd and Pb were 98, 30, 78, 0.22 and 26mg/kg, respectively, which were 1.46, 1.11, 0.82, 2.75 and 0.96 times of the soil background values in Hunan. The total ecological risk posed by the metals in the study area followed the trend Yueyang South Lake>Huanggai Lake>Huarong East Lake. And Cd was the most widely contributed and most concentrated element. In the STIRPAT expansion model, the standardized coefficients of the total population, urbanization rate, actual GDP per capita, the secondary industry ratio, the tertiary industry ratio, the mining and manufacturing were 0.1396, 0.0969, 0.1922, 0.1367, 0.1264 and 0.1929, respectively, indicating that the mining and manufacturing production, actual GDP per capita, and the total population had the greatest impact on Cd pollution. Therefore, the mining and manufacturing had a great impact on Cd pollution in lakes. The conclusion was not accurate to assess the lake sediment risk through soil backgrounds. This study provides important guidance for watershed environmental baseline study, pollution prevention, environmental management, pollution control, and especially supporting the protection of the Yangtze River.
2023 Vol. 43 (4): 1812-1823 [Abstract] ( 250 ) [HTML 1KB] [ PDF 1124KB] ( 1047 )
1824 Ecological security pattern construction in Lijiang River basin based on MCR model
YANG Shuai-qi, HE Wen, WANG Jin-ye, LI He-ying, YAO Yue-feng
The construction of ecological safety network system plays a critical role in ecological protection and restoration for people's welfare and national security. In order to construct a better ecological security pattern, we took the Lijiang River basin with typical karst landforms as a research example, to extract ecological source sites with landscape ecological risk and connectivity indices, to identify and grade the potential ecological corridors and nodes with the minimum cumulative resistance and gravity models, and finally to construct the regional ecological security pattern in a coordinated way the conservation of Mountains-Rivers-Forests-Farmlands-Lakes-Grasslands-Deserts ecosystem. The results showed that: (1) The ecological risk of the Lijiang River basin was characterized as high in the center and south, and low in the east and north. The high and higher risk areas accounted 43.34% of the total watershed area. (2) There were five ecological source areas, mainly located in forests and nature reserves, accounting for 28.99% (1689.05km2) of the total watershed area. (3) Six potential ecological corridors and 38 potential ecological nodes were identified, which were concentrated in the vicinity of Lingtian town. (4) The Lijiang River basin was constructed as a protective pattern of ecological conservation, restoration, control, and corridor construction. In addition, more ecological compensation funds and techniques should be supported to Lingchuan and Xingan counties in order to ensure the successful construction of the corridor. We hope this study could provide scientific knowledge for improving the ecosystem function of the Lijiang River basin and the successful implementation of national land use plan.
2023 Vol. 43 (4): 1824-1833 [Abstract] ( 315 ) [HTML 1KB] [ PDF 4322KB] ( 1061 )
1834 Suitable ecological water level of Lake Taihu
WU Dong-hao, CHEN Fang-fei, MENG Xiao-chen, WU HAO-yun, WU Ya-nan, CHEN Hong
Water level is an important basic hydrological element, and its variation characteristics have an important impact on the structure and function of the lake ecosystem. Based on the long series of monitoring data from 2000 to 2020, the characteristics and correlation of hydrology, water environment and water ecology of Lake Taihu were analyzed. The results showed that the water level of Lake Taihu had risen since 2000, the concentration of total phosphorus and chlorophyll-a had risen fluctuated, and the distribution area of submerged plants had decreased obviously. The water levels from January to February, March to April, January to April, May to July and days over 3.5m were significantly negatively correlated with the distribution area of submerged plants in May of that year. The annual average water level, the water level from August to September and the number of days over 3.5m were significantly negatively correlated with the area of submerged plants in May of the next year. However, the influence of water level on the area of submerged plants in August was relatively weak when compared with May. The region between East and West Mountains of Lake Taihu and Dongjiaozui were potential key recovery areas for submerged plants. Based on the life history of submerged plants, the establishment method of suitable ecological water level of Lake Taihu was put forward for the first time, and the appropriate ecological water level was established. The appropriate ecological water level was more conducive to the germination and initial growth of submerged plants, and maintains a good hydrological rhythm. Due to the adaptability of submerged plants to long-term high water level in Lake Taihu, the fluctuation of water level in the short term would not lead to a drastic decrease in the distribution area of submerged plants. Artificial water grass harvesting was the main reason for the sudden decrease of submerged plant area in Lake Taihu in 2015. Reducing water level is one of the effective means to restore submerged plants in Lake Taihu, but flood control, water supply, water ecology and water environment in the basin all have different demands on the water level of Lake Taihu, so it is necessary to coordinate water security, water resources, water ecology and water environment, and to establish a multi-objective coordinated water level of Lake Taihu as soon as possible.
2023 Vol. 43 (4): 1834-1843 [Abstract] ( 326 ) [HTML 1KB] [ PDF 1173KB] ( 1655 )
1844 Seasonal characteristics of precipitation in Tianjin and sources of ion from different air masses
YANG Jing-ai, HAN Shao-qiang, YANG Jian-an, WANG Ji-lu, LIU Jin-guan, TIAN Yu, ZHANG Ya-ni, XUE Peng-fei, WANG Yan-li, ZHAO Zhi-qiang, CHEN Chen, CUI Lian-xi, YANG Hua, ZHANG Jing
Based on the atmospheric precipitation samples from March 2019 to February 2022 in Tianjin, the seasonal changes of precipitation and the sources of inorganic ions and organic acids were analyzed. The mean pH value of precipitation was 6.68, and the mean conductivity was 46.8μS/cm, and the mean value of total ion concentration was 726μeq/L. The precipitation ions generally showed the seasonal character of "high in winter and low in summer". SO42- and NO3- accounted for 89.6% of total free acidity (TFA) and were the main acid causing ions. According to the HYSPLIT model, precipitation was mainly caused by five incoming air masses. In spring and winter, the main source was the high-ion-concentration air mass from northern and northwest areas. These two accounted for the largest proportion, which reached 60.0%~62.5%. In summer and autumn, the precipitation was mainly caused by the low-ion-concentration air mass from southern, eastern and southeast areas, the sum of which accounted for 60.0%~97.8%. Enrichment factor analysis showed that Ca2+, Mg2+ and K+ mainly came from soil, Cl- mainly came from the ocean, Na+ came from sources included soil, while SO42- and NO3- mainly came from anthropogenic sources. In addition, according to the sources of organic acids, direct sources, such as plant growth and soil release, had a greater contribution to the organic acid concentration in Tianjin, while indirect sources, such as atmospheric photochemical reaction of unsaturated hydrocarbons, had a smaller contribution. Positive matrix factorization (PMF) source analysis showed that the ion sources of atmospheric precipitation in Tianjin included biomass combustion, garbage incineration, secondary inorganic sources, biological emissions and secondary organic sources, sea and industrial sources, as well as land and fugitive dust.
2023 Vol. 43 (4): 1844-1856 [Abstract] ( 208 ) [HTML 1KB] [ PDF 1075KB] ( 809 )
1857 Macroinvertebrates community structure in relation to environmental variables in the lower reaches of the Yalong River
ZHANG Kui, ZHOU Lian-feng, CHEN Wei, SHAO Ke, WU Wen-yong, CHEN Yu-lin, YANG Han, MA Pei-ming
Surveys with 22 sampling sites were conducted in spring (May) and autumn (October) of 2020 to understand the impact of cascade hydropower development on macroinvertebrate community structure in the lower reaches of the Yalong River. The characteristics of macroinvertebrate community structure and its relationship with environmental variables at different groups of sampling sites (natural river sections, upstream and downstream of the dams) were analyzed. The results showed that a total of 82 macroinvertebrate species (genera) were identified and the dominant species were Chironomus sp. and Baetis sp.. In comparison to previous studies, the dominant species were only the species that adapted to static or slow-flowing water, and the species that adapted to fast-flowing water were not dominant anymore since the cascade hydropower development. The densities of macroinvertebrates in spring were significantly lower than those in autumn (n=42, P<0.05). However, no significant difference was found in density, biomass, richness, or the Shannon-Wiener diversity index between spring or autumn and among different groups of sites. PCoA and Adonis paired test analysis showed that there was no significant difference in community structure among sites from natural river sections, upstream of dams and downstream of dams in spring and autumn, respectively. In the temporal domain, the difference in community structure between spring and autumn was significant (n=42, P<0.01), and the main contributor was chironomid larvae. The CCA and Envfit analyses revealed that the main factors influencing the macroinvertebrate community structure in spring were Chl-a and CODMn, and in autumn NO2--N, TN, T, and EC.
2023 Vol. 43 (4): 1857-1866 [Abstract] ( 315 ) [HTML 1KB] [ PDF 1264KB] ( 1650 )
1867 Downscaling method of precipitation data based on GBDT combined with multiple eigenfactors
ZHANG Han-bo, YANG Ji, JING Wen-long, DENG Ying-bin
A spatial downscaling framework based on machine learning algorithms integrated with station data correction is proposed by combining enhanced vegetation index (EVI), precipitable water vapor (PWV), Land Surface Temperature (LST), Slope, Aspect, Altitude, LON, and LAT. Then, the robustness differences among three machine learning algorithms, namely Random Forest (RF), Feedforward Neural Network (FNN), and Gradient Boosting Decision Tree (DBGT), were evaluated for spatially downscaling the GPM IMERG over the Yangtze River basin. The time-lag effect of different seasonal vegetation on the downscaling results of precipitation from 2001~2019 was taken into account to explore how the correction effect of the downscaling framework on GPM is related to the precipitation. The results show that the three downscaling approaches can improve the accuracy of the data to different degrees while obtaining the GPM IMERG data with 1km spatial resolution. Specifically, the simulations of GBDT can express the detailed features of precipitation more obviously in terms of the spatial heterogeneity with the best simulation accuracy and stronger model robustness at annual and seasonal time scales in each study area (annual R2=0.748~0.958, seasonal R2=0.518~0.909). The hysteresis of vegetation in spring and winter were most sensitive to the response of GPM downscaling results, with the best hysteresis of 1and 2months in order. Yet the time lag effect was not significant in summer and autumn, with no lag period essentially. Compared to the original data, the increased R2of the downscaled data was positively correlated with precipitation at R2 of 0.630~0.844.
2023 Vol. 43 (4): 1867-1882 [Abstract] ( 202 ) [HTML 1KB] [ PDF 4456KB] ( 2490 )
1883 The coupling and coordination of complex ecosystem based on the InVEST model-A case study in the Lanzhou-Xining urban agglomeration
ZHAO Wu-sheng, SHI Pei-ji
This paper measured the economic and social development of the Lanzhou-Xining urban agglomeration by the exponential efficacy function model. Based on the InVEST model, the level of ecosystem services in the urban agglomeration was assessed and the coupling coordination model was used to analyze the coupling coordination of economic-social-ecological subsystems as well as the spatial and temporal variation characteristics. The results showed that: From 2000 to 2020, the development of economic and social subsystems of the Lanzhou-Xining urban agglomeration showed a typical“double core” pattern, with insufficient development of the sub-centres of the urban agglomeration and a clear distribution of low-level counties. Water conservation, soil and water conservation, and carbon sequestration and oxygen release services were all on the increase and presented different spatial heterogeneity; The integrated ecosystem services showed a stepwise progression from northeast to southwest. The high values were concentrated in the three rivers source area and the low values were in Baiyin City. The economic-social-ecological subsystem was highly coupled, with a consistent overall evolutionary trend and close interaction. The coordination increased by 14.63%. The high-value areas were located in the built-up areas of cities and states, while low-value value areas were concentrated in the northeastern part of the urban agglomeration. In the coordination degree partitions, lag subsystems were different.
2023 Vol. 43 (4): 1883-1894 [Abstract] ( 321 ) [HTML 1KB] [ PDF 2623KB] ( 3083 )
1895 Distribution characteristics and aggregating and releasing of heavy metals during Summer in a cascade Reservoir of the upper and middle reaches of the Heihe River
WANG Yu, ZHU Jia-le, FENG Qi, LIU Wei, HE Yu-hua, WANG Xu, LIU Kai-qing
To explore impacts of a cascade reservoir on the spatial distribution of heavy metals in rivers, we collected samples (including water, sediment and shoreside soil) from the trunk and tributaries of the upper and middle reaches of the Heihe River in August 2019 to determine the contents of Cr, Cu, Ni, Pb, Zn, Cd, Mn and As elements. The spatial distribution and sources of these heavy metals were analyzed through inverse distance weighting and principal component analysis. The result show that these elements were still in the "sink" stage in the middle and upper reaches. Damming for impoundment had the "interception effect" due to the different migration and release capacities of various heavy metals. A small portion of heavy metals was "intercepted" in the middle reservoir area and a significant enrichment in the trunk stream and its tributaries due to the hydraulic characteristics of their confluences. Furthermore, As, Cd, Pb, Zn and Cu were mainly resulted from mineral exploitation, while Mn, Cr and Ni from industrial production, urban sewage and natural factors, respectively. According to the horizontal characteristics of Cu concentration, sediments and soils on the shores indicated mineral exploitation near the sections. The findings could provide a reference to the control and effective management of heavy metals in the cascade damming reaches of China.
2023 Vol. 43 (4): 1895-1905 [Abstract] ( 266 ) [HTML 1KB] [ PDF 3304KB] ( 807 )
Carbon Emission Control
1906 Carbon emission structure and carbon peak of agriculture and rural areas in China
ZENG Xian-gang, YU Chang, SUN Ya-qi
This paper presents the carbon emissions and carbon intensity of farming, animal husbandry and rural households, and analyses their differences and convergence. The results indicate that the carbon emissions from the farming industry and the livestock industry in China peaked at 688.2102 million tons and 399.094 million tons of carbon dioxide in 2015, while the carbon emissions from the agricultural and rural areas as a whole peaked at 1500.39 million tons of carbon dioxide in 2017; in terms of the emission structure, about 50% of the carbon emissions attributed to the farming industry, while the proportion of carbon emissions from residential life rose sharply, accounting for about 30% in 2019, which mainly originated from residential energy consumption; with regard to the overall carbon emission intensity of agriculture and rural areas, the changes in the Thiel index indicate an overall increase in variance, and the σ convergence and β convergence results indicate a convergence of carbon emission intensity to the overall average level. Agriculture is crucial to food security, and after the carbon peak, food production should be ensured while meeting the carbon neutrality target. In the future, it has to improve the quality of arable land, promote high-yielding low-carbon varieties, enhance the utilization rate of agricultural production factors, and develop agricultural technology, lifting technology efficiency and achieving sustainable carbon emission reduction.
2023 Vol. 43 (4): 1906-1918 [Abstract] ( 311 ) [HTML 1KB] [ PDF 897KB] ( 2968 )
1919 Spatial and temporal distribution of CO2 concentration in mainland China and its influencing factors
RENYANG Qian-qian, LIAN Yi, LI Hai-xiao, GAO Hui-chun, DONG Jian-kang, HE Meng-xuan
This paper analyzes the spatiotemporal characteristics of CO2 concentration distribution in China mainland during 2015~2019 and the driving factors by integrating CO2 data from the European Centre for Medium-Range Weather Forecast (ECMWF), MODIS data, and population, GDP, energy consumption data from China Yearbook. The results of geographically weighted regression analysis and correlation analysis show that the atmospheric CO2 in China rose periodically. Human activity is the principal factor affecting CO2 concentration. The effects of natural and human activities on atmospheric present high heterogeneity in different regions.
2023 Vol. 43 (4): 1919-1929 [Abstract] ( 325 ) [HTML 1KB] [ PDF 2609KB] ( 1066 )
1930 Estimation on net carbon emission from organic carbon transport caused by Three Gorges Dam
XING Ran, QIN Bo-qiang, BAO Yu-fei, DAI Jiang-yu, ZENG Chen-jun, ZHU Lin, SHI Wen-qing
In order to quantify net carbon emissions from the Three Gorges Reservoir, China, this study clarified carbon biogeochemical cycles, and estimated carbon emissions during organic carbon (OC) transport along Yangtze River in the scenarios with and without Three Gorges Dam. Results demonstrated that Three Gorges Dam doesn’t increase but decreases carbon emissions by (23.24 ±1.05)%. Three Gorges Dam redistributes OC and transfers the hot spots of OC decomposition and carbon emissions from Yangtze River estuary to Three Gorges Reservoir. In the reservoir, the effective OC burial decreases net carbon emissions, although anoxic conditions enhance methane production.
2023 Vol. 43 (4): 1930-1936 [Abstract] ( 281 ) [HTML 1KB] [ PDF 514KB] ( 1103 )
1937 Review on emission reduction strategies of greenhouse gases in urban drainage network
XIONG Jie, ZUO Xiao-jun, LI Lu-cheng, LI Ting, LU Jian-gang
In this study, microbial characteristics in urban drainage network were introduced, and the generation mechanism of greenhouse gases (GHGs) was analyzed, after summarizing the research status of GHGs in urban drainage networks at home and abroad. Furthermore, the physical and chemical methods (like Ferrate) of controlling CO2, CH4, and N2O were discussed, and finally, potential strategies for the emission reduction of GHGs in urban drainage networks were given. It is suggested that both natural chemical control (e.g., Urine) and resource utilization should be studied well to provide data and theoretical support for carbon emission reduction from urban drainage systems in future.
2023 Vol. 43 (4): 1937-1945 [Abstract] ( 344 ) [HTML 1KB] [ PDF 386KB] ( 1881 )
1946 Influencing factors and promoting measures of industrial pollution abatement and carbon reduction of the city clusters in the Yellow River basin
KANG Zhe, LI Wei, LIU Wei
The Hohhot-Baotou-Ordos-Yulin, Guanzhong Plain, and Zhongyuan city clusters were selected for this analysis of emission trends based on the measurement of industrial CO2 and local air pollutant (LAP) emissions from 2000 to 2019. Further, a random forest model was used to identify the key influencing factors of pollution abatement, carbon reduction, and the nonlinear response relation among them. Strategies for promoting pollution abatement and carbon reduction were proposed according to local conditions. The results showed that industrial CO2 emissions were on the rise, whereas the emission intensity of the Guanzhong Plain and Zhongyuan city clusters were on the decline. Furthermore, the strong potential for a reduction in carbon emissions and LAP emissions and intensity remained. The trends in industrial CO2 emissions and industrial LAP emissions were not simultaneous. Among the key influencing factors, industrial added value above designated size and energy consumption per 10000 yuan industrial added value were shared by both industrial CO2 emissions and LAP emissions. The proportion of high-tech industries in industrial value added, the proportion of R&D expenditures in the GDP, and the industrial sulfur dioxide removal rate were the key influencing factors for LAP emissions, and differences existed across city clusters. Some indicators showed that a significant nonlinear response relation, the industrial scale effect, the distortion of R&D personnel and funds, and the lag of green technology utility were important factors in terms of nonlinear characteristics. To realize the synergistic promotion of pollution reduction and carbon reduction, carbon reduction could be prioritized, and the upgrading of industrial structure, along with the dual control of both energy consumption and intensity should be promoted. Finally, an improvement in energy efficiency is needed.
2023 Vol. 43 (4): 1946-1956 [Abstract] ( 238 ) [HTML 1KB] [ PDF 1030KB] ( 1156 )
Environmental Toxicology and Health
1957 Cardiotoxicity and oxidative damage of phosalone exposure on zebrafish embryos
SHENG Zhong, CHEN Jia-le, WANG Bin-jie, WU Yuan-zhao, YAO Wei-xuan, WANG Ji-ye
The effects of acute exposure to sublethal doses of phosalone on the development of zebrafish embryos were evaluated in terms of cardiotoxicity and oxidative damage. The results showed that the hatching rate of zebrafish embryos decreased by 10.37% and 22.96% at 1and 3mg/L, respectively, and the body length shortened by 11.77% and 19.40%, respectively, and the heart rate decreased significantly, resulting in embryonic developmental abnormalities such as pericardial edema. Superoxide dismutase (SOD) activity significantly increased after exposure to phoslone at concentrations of 0.3mg/L and 1mg/L, but decreased in the 3mg/L group;catalase (CAT) activity decreased significantly in zebrafish larvae; the reactive oxygen species (ROS) assay showed that the heart of zebrafish was the main organ responsible for oxidative damage; transgenic zebrafish (cmlc2:EGFP) showed increased separation of atria and ventricles; the expression of nppa and sox9b were significantly up-regulated and gata4 and vmhc were significantly down-regulated in heart development-related genes; the expression of apoptosis-related genes bcl2, bax, Puma and Mdm2 were significantly down-regulated. The result suggested that the cardiotoxicity induced by phosalone exposure was associated with oxidative damage and disruption of apoptotic cell homeostasis.
2023 Vol. 43 (4): 1957-1966 [Abstract] ( 222 ) [HTML 1KB] [ PDF 1982KB] ( 693 )
1967 Effects and mechanisms of cellular senescence induced by typical PM2.5 components in MRC-5 cells
XU Xiao-an, XU Sheng-min, WU Li-jun
To investigate the effects and mechanisms of PM2.5 and its typical components on cellular senescence in lung tissue, human fetal lung fibroblast cells (MRC-5) were exposed to SRM1649a as PM2.5 standard, carbon black FW200 as the core particle, and benzo[a]pyrene (B[a]P) as the main organic component, respectively. The experiments were conducted to assess the cellular senescence of MRC-5 cells by measuring SA-β-Gal activity and clarify the mechanism of cellular senescence induced by intracellular reactive oxygen levels, DNA damage and mitochondrial membrane potential. It was showed that the treatment of SRM1649a and B[a]P significantly increased the proportion of cellular senescence in MRC-5 cells with no obvious effect on cellular viability, whereas cellular senescence was not remarkably changed in the FW200-exposed group. Mechanism studies indicated that FW200 treatment caused only DNA damage rather than cellular senescence, while exposure to B[a]P induced cellular senescence by triggering changes in ROS levels. Furthermore, the mixture SRM1649a could lead to DNA double-strand breaks and decrease the mitochondrial membrane potential, which induced cellular senescence in terms of DNA damage and mitochondrial dysfunction. These results suggested that the toxic effects induced by the main components of PM2.5 were different, and synergistic promoting effects are manifested in PM2.5 as the mixture.
2023 Vol. 43 (4): 1967-1977 [Abstract] ( 265 ) [HTML 1KB] [ PDF 3252KB] ( 1060 )
1978 The combined development toxicity of microplastics with different shapes and mercury on Zebrafish embryos
SHI Yan-song, WANG Jing, CUI Wen-jie, WANG Yu-di, ZHANG Hai-hong, DUAN Zheng-hua
To explore the toxicity of microplastics with different shapes to organisms, the toxicity effects of polyethylene terephthalate (PET) granules (approximately 70~250μm in diameter) and fibers (approximately 3~5mm in length and 20μm in diameter) combined with heavy metal mercury (Hg) on zebrafish embryo development were compared in the present study. The results showed that the single exposure of Hg to zebrafish embryos resulted in embryonic development toxicity (such as blood flow development disorder, cardiac relaxation, and reduced hatching rate), pericardial sac edema, and tail malformations. The malformation rates at 48 and 72h were as high as 31.3% and 91.7%, respectively. Fibrous (f-PET) and granular (p-PET) microplastics could reduce the embryonic toxicity of Hg. From the data of metabolomics, the disorder effects of glucose metabolism and amino acid metabolism caused by Hg on zebrafish larvae were significantly reduced in combined exposure of microplastics and Hg (P< 0.01). However, due to the difference in the adsorption capacity and process of Hg, p-PET significantly alleviated the 24-h blood flow disorder effect caused by Hg, while it was not as significant as f-PET in reducing the toxicity of Hg to zebrafish embryos in the later period of exposure. Thus, the combined toxic effect of microplastics and Hg was related to the shape of microplastics.
2023 Vol. 43 (4): 1978-1984 [Abstract] ( 329 ) [HTML 1KB] [ PDF 619KB] ( 1586 )
1985 Effects of antibiotics on toxicity and halocarbons release of microalgae
YAN Xue-feng, YANG Bin, YU Hong, YANG Gui-peng, HE Zhen
The toxicity of sulfamethazine (SMZ) and oxytetracycline (OTC) to Skeletonema costatum and the potential effects on the release of volatile halocarbons (VHCs) were investigated. The results showed that 10mg/L SMZ and OTC significantly inhibited the growth of Skeletonema costatum in the middle and later period of the culture process. The maximum inhibition rates of cell density, chlorophyll a concentration and Fv/Fm reached the maximum, which was 90.74%, 91.25%, 83.46%, 87.16%, 87.04% and 87.43%, respectively. The soluble protein content under antibiotic exposure was significantly lower than that in the control group. Catalase activity increased first and then decreased with the increase of antibiotic concentration and the prolongation of exposure time, indicating that long-term and high concentration exposure of the two antibiotics showed obvious toxic effects on microalgae, with the toxic effect of SMZ being higher than that of OTC. Antibiotic exposure induced an increase in intracellular reactive oxygen species (ROS) production. In addition, the addition of antibiotics can promote the release of VHCs in different degrees. It may be that the halogenation reaction of H2O2 catalyzed by haloperoxidase (HPO) produce more volatile halocarbons as antioxidants against oxidative stress to avoid the damage caused by excessive ROS to algal cells. These results indicate that the response of release of the three volatile halocarbons from microalgae to antibiotics was controlled by the biomass of algae and the catalytic mechanism of HPO enzyme.
2023 Vol. 43 (4): 1985-1994 [Abstract] ( 272 ) [HTML 1KB] [ PDF 517KB] ( 1062 )
Environmental Microbiology
1995 Characteristics of soil fungi community in wild populations of three Paphiopedilum Subgen Brachypetalum species
TIAN Li, AN Ming-tai, ZHANG Yang, WU Mo-xu
Paphiopedilum armeniacum, Paphiopedilum wenshanense and Paphiopedilum concolor as the research object, research habitat information, uncover the structural characteristics of soil fungal compositions and the associated environmental factors would provide the basis for efficient protection and cultivation. In this study, we investigated the habitat parameters and soil fungal community using samples collected from the natural habitats of the three species. The structural characteristics, diversity of fungal communities, fungal functional groups and the associated environmental factors were preliminarily analyzed by ITS high-throughput sequencing. A total of 1105 operational taxonomic units (OTUs) were obtained from 27 samples, 322 fungi were identified, belonging to 10 phyla, 29 classes, 70 orders, 151 families, 256 genera, respectively. There were 48 common OTUs in the habitat of three Subgen Brachypetalum species, 489 unique OTUs in P. concolor, 221 in P. wenshanense and 202 in P. armeniacum. There were different dominant groups at the taxonomic level of phylum, class, family and genus in the habitat of three Subgen Brachypetalum species. The fungal functional groups annotation found that the soil fungal functional groups in the habitat of three Subgen Brachypetalum species were dominated by saprophytic fungi and exogenous mycorrhizal fungi. The functional groups of habitats of P. concolor are more complex than other two species; Alpha diversity analysis results showed the congruence in the ACE index and Chao1index. The Simpson index and Shannon index of P. concolor were significantly higher than those of P. armeniacum, and were extremely significantly higher than those of P. wenshanense. Beta diversity analysis showed that there were significant differences in soil fungal community composition and structure among the habitat of three Subgen Brachypetalum species (P = 0.001), and the higher the classification level. Redundancy analysis found that latitude and longitude and vegetation types were the most important factors affecting the changes of soil communities of habitat of three Subgen Brachypetalum species, and all environmental factors accounted for 44.08% of the changes in fungal communities. Mantel test found the alpha diversity of soil fungi of habitat of three Subgen Brachypetalum species was significantly controlled by soil pH. Spearman correlation analysis confirmed that a variety of fungal dominant groups were significantly correlated with soil physical and chemical factors. Taken together, all these data suggest different composition of soil fungal communities, fungal functional groups and fungal diversity in the habitat of three Subgen Brachypetalum species. The composition and structure of soil fungal communities are mainly resulted from differences in environmental factors, and the distribution of dominant fungal communities are associated with changes in the soil physical and chemical properties.
2023 Vol. 43 (4): 1995-2006 [Abstract] ( 230 ) [HTML 1KB] [ PDF 2466KB] ( 1002 )
2007 Influences of environmental substrates on microbial quorum-sensing signals
CHENG Yang-juan, HUANG Dan, WANG Yu-fan, WANG Mei-zhen
Quorum sensing (QS) is a bacterial conversation mechanism that regulates free radical release, biofilm formation, and gene level transfer by releasing signaling molecules for intercellular communication. The media materials widely present in the environment can interact with signaling molecules and thus influence the behavior of microorganism populations. Although there are many reviews on QS signal molecules and their regulatory mechanisms, the effects of environmental substrates on intracellular and extracellular signal molecules have not been well synthesized. Therefore, this study aims to elucidate the structure-function relationships between signal molecules and environmental substrates by reviewing the physicochemical properties and biological functions of various signal molecules of microorganisms and evaluating the effects of environmental substrates, such as soil minerals, nanomaterials, biochar and natural small molecule compounds, on signal molecules, so as to provide a vital reference for the in-depth understanding of the QS regulation of microbial communities in a realistic environment.
2023 Vol. 43 (4): 2007-2016 [Abstract] ( 334 ) [HTML 1KB] [ PDF 430KB] ( 1988 )
2017 The effects of tourism-related trampling on the root-associated fungal community of Fanjing Mountain
LIU Min, ZHANG Tao, LI Long, ZHENG Rong, YANG Chuan-dong, WANG Zu-hua
The aim of this study was to explore the responses of the root-associated fungal community to tourism-related trampling at different elevations on Fanjing Mountain. Extremely high trampling plots, high trampling plots, moderate trampling plots, light trampling plots and no trampling plots were established at 1100, 1500 and 2000m, and root samples were collected in the plots by the point-centered-quarter method. The characteristics of root-associated fungal community were evaluated by high-throughput sequencing technology. Ascomycota was the dominant phylum, while Hyaloscyphaceae, Dermateaceae, Herpotrichiellaceae and Glomeraceae were the most abundant families. Higher fungal richness and diversity were found in the plots with moderate or light trampling, and two-way permutational multivariate analysis of variance showed that tourism-related trampling, elevation, and the tourism trampling×elevation interaction significantly affected the root-associated fungal community. The changes in root-associated fungal richness were mainly driven by elevation, tourism-related trampling, root tissue density and leaf biomass; elevation, tourism-related trampling, specific root length, root carbon content and leaf biomass were the important factors influencing the Shannon index. The changes in tourism-related trampling, elevation, soil total carbon, soil total phosphorus, root carbon content, mean root diameter, leaf biomass and leaf carbon content significantly affected root-associated fungal community structure, and the nitrogen and phosphorus contents explained the vast majority of the differences in root-associated fungal community composition.
2023 Vol. 43 (4): 2017-2027 [Abstract] ( 243 ) [HTML 1KB] [ PDF 1573KB] ( 1625 )
2028 Environmental factors affecting yeast community structure during different hydrological periods in Nam Co Lake
WANG Yan-hong, HAO Zhao, XUE Wen-kai, MENG Hua-dan-shang, DE Ji, GUO Xiao-fang
Structure of the culturable yeast community in Nam Co Lake was investigated in August 2020 (wet season) and May 2021 (dry season). As a result, 2411 yeast isolates belonging to 33 genera (70 species) were identified. Bioinformatics and statistical analysis indicated that the total abundance, species composition and community structure of yeasts were significantly different between different periods. Moreover, pH, electrical conductivity, chemical oxygen demand, and total nitrogen in the dry season were significantly higher than those in the wet season. The neutral community model and correlation analysis showed that the yeast community structure was more influenced by deterministic processes, and ammonia nitrogen, total phosphorus and chemical oxygen demand were the remarkable factors that could influence the yeast community structure in Nam Co Lake. Niche measurement indicated that niche breadth and niche overlap value of the dominant species of yeasts in the dry season were lower than those in the wet season. Environmental factors have larger impact on resource utilization pattern and interspecific relationship of the dominant yeast species. Water quality monitoring would contribute to the conservation of yeast resources in Nam Co Lake, especially during the dry season.
2023 Vol. 43 (4): 2028-2038 [Abstract] ( 228 ) [HTML 1KB] [ PDF 1515KB] ( 1035 )
2039 Analysis of the dispersal process of abundant and rare subcommunities in highly artificial urban rivers: A case study of the North Canal River
ZHANG Wei, GUO Xiao-yu, WANG Min, LIANG Ji, WU Dong-li
Basing on the qualitative and quantitative data of microorganisms, the spatial dispersal processes of abundant and rare subcommunities were measured by the land diffusion PCNM model (principal coordinators of neighborhood matrices), the asymmetric stratified branching diffusion MEM model (Moran eigenvector map) and the unidirectional diffusion AEM model (asymmetric eigenvector map) in a heavily polluted urban river, the North Canal River. The results showed that the fitness of models of abundant subcommunities was significantly higher than that of rare subcommunities. The AEM model of abundant subcommunities had a high fitness value, while there were no significant difference in the fitness of rare subcommunities models. Comparing to the MEM model, The PCNM and AEM models explained more spatial variations of abundant and rare subcommunities. The high fitness value based on the quantitative data matrix than that of qualitative data matrix, indicating that the dispersal process was independent of environmental selection in both abundant and rare subcommunities in the highly artificial urban river. This was in line with the VPA (variation partitioning analysis) resulted that dispersal explained 18.3% and 7.4% of the variation in the abundant and rare subcommunities respectively, and environmental selection explained 18.6% and 7.6% of the variation. Abundant subcommunities showed a significant distance-decay relationship, and the synergy of environmental factors such as total nitrogen (TN) and total phosphorus (TP) were important to the diversity construction in the abundant subcommunities. These results provided theoretical and technical support for the construction mechanism of planktonic microbial diversity in the highly artificial urban river.
2023 Vol. 43 (4): 2039-2046 [Abstract] ( 207 ) [HTML 1KB] [ PDF 811KB] ( 1204 )
Environmental Impact Assessment and Management
2047 The Promoting the Big and Quashing the Small Policy reduced the air pollutant emissions from China’s coal power supply chain perspective
LI Jia-shuo, SUN Qian-hui, WANG Wen-xin, YANG Fan
This paper investigated the mitigation effect of the promoting the big and quashing the small policy (PBQSP) on air pollutant emissions from China’s coal-fired power plants (CFPPs) between 2011 and 2018 by building a coal supply chain network based on the plant-level CFPP information in China. Results show that, while China's coal power generation increased by 38.6% from 2011 to 2018, NOx SO2, and Hg emissions from coal power supply-chain increased merely by 10.4%, 16.2%, and 6.8%, with PM emissions decreasing by 15.8%. Compared to decommissioned CFPPs, newly-built CFPPs reduced their NOx, SO2, PM, and Hg emission intensities along their coal supply chain by 63.2%, 62.1%, 90.2%, and 67.8%, respectively. The emission intensities at the power generation stage had the largest decrease; but remained similar at the coal mining stage and declined slightly at the transport stage, respectively. This study also proposed strategies to enhance the mitigation effect of the PBQSP, including optimizing the site selection of newly-built CFPPs, enhancing the coal mine management, and improving the end-of-pipe emission control for CFPPs. It also serves as an important reference to exploring emission reduction paths in other pollution-intensive industries.
2023 Vol. 43 (4): 2047-2056 [Abstract] ( 285 ) [HTML 1KB] [ PDF 1370KB] ( 1381 )
2057 Spatial relatedness of CO2 emission and carbon balance zoning in Beijing Tianjin Hebei counties
ZHANG Zheng-feng, ZHANG Dong
Based on the carbon emission / carbon sink data in 2005, 2010, 2015 and 2017, an empirical study on the spatial connection of carbon emission / carbon sink at the county level of Beijing, Tianjin and Hebei (BTH) was made by using social network analysis and exploratory spatial data analysis, and divides the carbon balance zoning, providing the path to divide the carbon balance zoning on the county spatial scale. The results showed that (1) the average annual growth rate of carbon emissions in the BTH region slowed down from 10.05% in 2005~2010 to 1.25% in 2010~2017. The total amount of carbon sinks decreased first and then increased, with an increase of 15% in 2010~2017. However, the net carbon emissions reached 600 million tons in 2017, reflecting that the current carbon neutralization pressure is still huge. The north and west of Beijing Tianjin Hebei were the main high-value areas of carbon compensation rate, and Beijing Tianjin Tangshan, Shijiazhuang, Handan-Xingtai and their surrounding areas were the low-value areas of carbon compensation rate; (2) The pattern of Beijing Tianjin Hebei carbon emission spatial network gradually became clear, forming three main carbon emission spatial linkage areas: Beijing Tianjin carbon emission area, Shijiazhuang carbon emission area and Handan carbon emission area, accounting for 36.65%, 9.64% and 6.76% of the whole respectively;(3) According to the results, BTH region was divided into 7 carbon balance functional areas: centralized carbon sink area, local regulation area, core linkage carbon emission area, dispersion linkage carbon emission area, dispersion Island carbon emission area, general linkage carbon emission area and general Island carbon emission area. 19 key counties inside were defined as core county, action county or bridge county, accounting for 22.07%, 32.62%, 12.81%, 0.45%, 1.14%, 22.55% and 8.36% of the whole respectively.
2023 Vol. 43 (4): 2057-2068 [Abstract] ( 305 ) [HTML 1KB] [ PDF 2853KB] ( 1902 )
2069 Introducing an incentive mechanism of reward and punishment distribution to the evolutionary game of the third-party governance of environmental pollution
HUANG Ren-hui, GAO Ming
To solve the problem of information asymmetry in third-party governance of environmental pollution under the background of fuzzy attribution of environmental responsibility, the tripartite evolutionary game model of polluting enterprise, third-party governance enterprise and local government was constructed by introducing the mechanism of incentive policy system on the strategic choice of parties and assessing the basic conditions for the system to achieve evolutionary stable state in different situations. Then, the scientificity of the game subject and system evolution stability analysis is verified with numerical simulation. The study indicates that, setting a reasonable amount of rewards and punishments and their distribution ratio, enhancing the reputational benefits of both enterprises, and controlling the cost of local government supervision are the key factors that affect the strategies choice of the three-parties. The reward and punishment distribution incentive mechanism designed according to the “responsibility sharing principle” demonstrates its effectiveness in promoting the trust and cooperation between the principal and agent; and the polluting enterprise shows stronger income sensitivity than the third-party governance enterprise does. To this end, the main responsibility status of polluting enterprise needs to be implemented, and the proportion of rewards and punishments shall be increased as much as possible.
2023 Vol. 43 (4): 2069-2080 [Abstract] ( 228 ) [HTML 1KB] [ PDF 1312KB] ( 1130 )
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