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  Current Issue
 
2024 Vol.44 Issue.8,Published 2024-08-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Ecology
Environmental Impact Assessment and Management
Environmental Toxicology and Health
Develpment of a beautiful China: Emerging Contaminants
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2024 Vol. 44 (8): 0-0 [Abstract] ( 75 ) [HTML 1KB] [ PDF 259KB] ( 632 )
Air Pollution Control
4145 Photochemical reaction characteristics and source apportionment of atmospheric volatile organic compounds during summer in Shenzhen
WU Hao-ran, PENG Xing, FU Nan, LI Zhi-jie, ZHONG Wen-jun, HE Ling-yan, HUANG Xiao-feng
Continuous online VOCs observation was carried out at urban sites in Shenzhen during the active photochemical reaction season from June to August 2022 (summer). The photochemical loss VOCs were evaluated based on the measured VOCs concentration using the photochemical age parametric method to obtain the initial VOCs concentration. The sources of initial VOCs were identified by the characteristic species ratio analysis method and Positive matrix factor model (PMF). The concentrations of photochemical consumption VOCs accounted for total VOCs (TVOCs) concentrations as follows: olefin (53.5%), oxygenated volatile organic compounds (OVOCs)(30.8%), alkane (10.9%), aromatic hydrocarbon (4.7%), acetylene (0.2%). Alkanes are dominant compounds in both initial and measured TVOCs concentration, but their photochemical loss ozone generating potential (OFP) is only 1.2×10-9, which is much lower than that of olefin (47.8×10-9), OVOCs(15.8×10-9) and aromatic hydrocarbons (4.7×10-9), suggesting that olefin is a key species for ozone pollution control. In this study, six major emission sources were obtained by PMF based on measured and initial VOCs concentrations respectively(Initial-PMF, Measured-PMF): industrial processes (0.91×10-9, 0.87×10-9), solvent use (2.75×10-9, 1.84×10-9), vehicle exhaust (3.49×10-9, 2.01×10-9), gasoline volatile (3.2×10-9, 2.62×10-9), natural source (0.74×10-9, 0.56×10-9), combustion source (2.35×10-9,1.16×10-9). It is suggested that PMF results are significantly affected by photochemical reactions, and the initial value of VOCs rather than the measured value should be considered in source apportionment, otherwise the exhaust gas and natural sources dominated by olefin will be significantly underestimated.
2024 Vol. 44 (8): 4145-4154 [Abstract] ( 193 ) [HTML 1KB] [ PDF 2463KB] ( 960 )
4155 Vertical variations of CO2/CH4 in winter based on observations at high-rise buildings in Shanghai
CHEN Long-long, XIAO Wei, YANG Fan, SHAN Meng, WANG Jun, HU Ning, LI Ruo-nan, CHENG Kai
In this paper, three portable greenhouse gas analyzers were used to continuously observe the atmospheric CO2 and CH4 concentrations at the heights of 255 and 500m at Shanghai Tower and 25m at Pudong New Area Environmental Monitoring Station from 6 December 2021 to 31 March 2022. The results indicated that: (1) the diurnal variabilities of the greenhouse gases at different heights in the city were different, with low value in daytime and high value at night for the 25m height, but opposite for the 255 and 500m heights. The CO2 and CH4 concentrations at each height were affected obviously by atmospheric boundary layer height, suggesting that vertical observation in cities must consider the variability of atmospheric boundary layer. (2) The vertical difference of the CO2 and CH4 concentrations were affected by anthropogenic activities and meteorological conditions, which can trace local and regional contributions. (3) The CO2 and CH4 concentrations were significantly correlated at each height (25, 255, 500m), and the correlation was weaker at greater height due to the interference of more emission and weak homology. The vertical observation of urban greenhouse gas concentration provided unique information that cannot be obtained from the horizontal observation. Therefore, three-dimensional greenhouse gas monitoring in cities was required to capture the change of atmospheric greenhouse gas concentration and to serve the urban carbon emission reduction policy.
2024 Vol. 44 (8): 4155-4166 [Abstract] ( 141 ) [HTML 1KB] [ PDF 2210KB] ( 1209 )
4167 PM2.5 acidity and secondary nitrate formation during typical pollution episodes of four seasons in Beijing
WANG You-feng, JING Kuan, SHEN Xiu-e, WANG Qin, WANG Chen-jing, FU Jia-ming, ZHANG Bo-tao, ZHANG Jian, CAO Yang, ZHANG Ke, LIU Bao-xian
Based on the online monitoring data from urban sites in Beijing during 2022, the ISORROPIA-II model was used to analyze the acidity of PM2.5 during four typical pollution episodes, namely haze pollution in winter, dust pollution in spring, high ozone pollution in summer, and PM2.5 and O3 combined pollution in autumn. The evolution of aerosol pH with the rapid formation of nitrate was obtained. The results show that the aerosol pH in Beijing was moderately acidic, in ranges of 3.59~5.07, 3.70~7.76, 2.44~6.15, and 2.80~4.69 for the four episodes, respectively. The aerosol pH exhibited normal distribution for the four pollution episodes with median values of 4.60, 4.59, 3.91 and 4.09, respectively. During winter haze pollution, aerosol water content and the aerosol pH were the highest. During spring dust pollution, the aerosol pH presented bimodal distribution, affected by both anthropogenic and natural sources. The acidity of PM2.5 in summer and autumn episodes was the strongest and the second strongest respectively, which might be related to the oxidation of acid gas enhanced by strong atmospheric oxidation conditions. During high ozone pollution in summer, with high temperature and low pH, HNO3 tended to be distributed in the gas phase, and the nitrate proportion in PM2.5 was the lowest (22%). For PM2.5 and O3 combined pollution in autumn, pH was low in the daytime and high in the nighttime, conducive to the nitrate accumulation at night after the gaseous HNO3 formation in the daytime. The nitrate proportion was comparable to that during pollution episodes in winter and spring, reaching 27%~28%. Gaseous NH3 was abundant, and the neutralization (homogenization) reaction between HNO3and NH3 was the main formation mechanism of NO3-. Abundant of NH4+, (NH4)2SO4, NH4NO3 and NH4Cl in aerosol could also be fully coupled. This research shows that high aerosol water content and aerosol pH were responsible for the rapid growth of nitrate during pollution. Further reduction of the precursors NH3 and NOx would be an effective means to control the fine particles in Beijing.
2024 Vol. 44 (8): 4167-4178 [Abstract] ( 176 ) [HTML 1KB] [ PDF 2142KB] ( 965 )
4179 Source apportionment and health risk assessment of metal elements in PM1 on different weather types during autumn and winter-A case study of Qingdao
DU Jin-hua, TAO Wen-xin, ZHANG Yi-sheng, LIU Zi-yang, YANG Jian-li, ZHANG Su-fan, WANG Chao-long, CUI Shan-shan, XUE-Lian, ZHANG Hou-yong, SUN Ying-jie
Over four consecutive autumn-winter seasons spanning from 2018 to 2022, a comprehensive analysis was conducted involving daily sampling of atmospheric PM1 and the subsequent examination of 20 distinct metal elements. The characteristics and sources of metal elements under different weather conditions were analyzed, and their health risks were assessed. The results revealed that on dust days, metal element content (2022.88±2298.00) ng/m3 and their proportion in PM1 (6.63%) were higher compared to other weather conditions. Specifically, the metal element content on haze and polluted fog days was 2.06 and 1.70 times higher than on clean days. Carcinogenic metal elements (Ni, Cd, As, Cr, Co, and Pb) and non-carcinogenic metal elements (Mn, Zn, Cu, V, Al, and Ba) showed higher enrichment factors on haze and polluted fog days. Positive matrix factorization (PMF) analysis identified primary sources of metal elements in PM1, including vehicular emissions, coal/biomass combustion, sea salt, crustal sources, industrial emissions, and maritime sources. Vehicular emissions and coal/biomass combustion notably contributed over 72.1% during foggy and hazy days, while maritime sources increased to 1.9% on clear fog days. Backward air trajectory analysis demonstrated that haze days were mainly affected by the transmission of pollutants from northwest to medium and long distances. Ocean-land circulation mainly affected polluted fog days, while dust days were dominated by long-distance transport of northwest dust masses. The non-carcinogenic risks via respiratory exposure to metallic elements in PM1 were deemed negligible. However, the lifetime carcinogenic risks of As and Cr exceeded the threshold of 10-6 but remained below 10-4, with the highest risk probability observed during polluted fog and haze days. Consequently, it's recommended to intensify emission control measures targeting As and Cr sources in industrial processes such as coal combustion, metallurgy, and electroplating, particularly during heavy pollution episodes in autumn and winter.
2024 Vol. 44 (8): 4179-4192 [Abstract] ( 148 ) [HTML 1KB] [ PDF 2640KB] ( 923 )
4193 Association between VOCs adsorption capacity of activated carbons and their diverse characteristic values
XIONG Ye-dong, KE Quan-li, HUANG Kang-Knag, MIN Jiong, JIN Chuan-min, ZHANG Pei-li, GU Zhen-yu, WEN Xiao-le, LU Han-feng
In this study, we investigated the relationship between the iodine number, carbon tetrachloride adsorption value (CTC value), total surface area, and micropore surface area of various activated carbon samples. We focused on their dynamic adsorption capacity for toluene, a representative volatile organic compound (VOC) found in exhaust gases. The results indicated that the CTC value showed a strong linear correlation with the adsorption capacity of activated carbon, regardless of toluene concentration in the exhaust gas. In contrast, the iodine number exhibited a better association with adsorption capacity only under low concentration conditions. This suggests that the CTC value is a more suitable indicator than the iodine number for evaluating the VOC adsorption performance of activated carbon. Furthermore, when oxygen-containing VOCs such as ethyl acetate were used as adsorbates, the CTC value also showed a favorable correlation with adsorption capacity. Beyond activated carbon, this study extended the methodology to different porous adsorbent materials, including silica gel, molecular sieves, and carbon-silica composites. The results demonstrated that the CTC value can also represent the VOC adsorption performance of these materials. This underscores the universality of the CTC value as a characteristic indicator of adsorption performance.
2024 Vol. 44 (8): 4193-4201 [Abstract] ( 169 ) [HTML 1KB] [ PDF 1401KB] ( 856 )
4202 The sources of volatile organic compounds in the summer atmosphere and the contribution to ozone generation in Changzhi, a typical industrial city
XING Yi-ran, NIU Yue-yuan, YAN Yu-long, PENG Lin, DONG Jia-qi, YUE Ke
In this study, taking Changzhi as a typical industrial city, the source apportionment of Volatile Organic Compounds (VOCs) was carried out used positive definite matrix factorization (PMF) model, and the atmospheric photochemical reaction process and O3 formation sensitivity were analyzed based on an observation-based model (AtChem-MCM). The results showed that the concentrations of alkanes, alkenes, alkynes and aromatics accounted for 57.49%, 16.05%, 9.17% and 17.29% of TVOC in Changzhi, respectively. PMF results showed that vehicle emission was the major source of VOCs (28.45%), followed by industrial process (26.19%), combustion sources (21.09%), biogenic sources (12.99%) and solvent utilization (11.28%). The simulation results of O3 formation showed that the average net formation rate of O3 during daytime was 23.01×10-9h-1, which reached a peak value (54.32 ×10-9h-1) at 11o'clock. The formation of O3 in Changzhi was sensitive to both VOCs and NOx, and alkene (1.05) and NOx (0.35) had the higher relative incremental reaction activity coefficients (RIR). Industrial process (0.072), solvent utilization (0.071) and vehicle emissions (0.068) had the higher RIR value, which were the key sources contributed to O3 formation. Therefore, industrial process and vehicles emissions should be strengthen for the control of O3 in industrial cities.
2024 Vol. 44 (8): 4202-4210 [Abstract] ( 132 ) [HTML 1KB] [ PDF 1521KB] ( 796 )
4211 Evaluation and analysis of MODIS and VIIRS satellite aerosol optical depth products over China
ZHOU Zhi-gao, HE Li-jie, ZHONG Yang, WANG Lun-che, QIN Wen-min, ZHANG Xiang
This study evaluates six aerosol optical depth (AOD) products from MODIS and VIIRS in terms of retrieval accuracy, spatial coverage, spatial distribution, retrieval frequency, and their performance in retrieving extreme weather events based on the Aerosol Ground-based Observation Network Data (AERONET). It also analyzes the error sources from the perspectives of land use type, aerosol mode, and seasonal variation. The results indicate that MODIS AOD products outperform VIIRS AOD products. Among them, the MAIAC AOD product has the highest accuracy, with a correlation coefficient R value of 0.83 and a proportion of 65.03% falling within the expected error (EE); In terms of spatial coverage and retrieval frequency, VIIRS AOD products significantly surpass MODIS; From respect of retrieving extreme weather events for individual cases, MODIS AOD products demonstrate better performance in dust events, but all products require further improvement in retrieving forest fire events; The land use type, aerosol mode, and seasonal variation have a significant impact on the retrieval accuracy of the six AOD products. Specifically, the six AOD products show the following characteristics. They show higher accuracy in built-up land but lower accuracy in cropland, and they mainly underestimate coarse mode aerosols while overestimating fine mode aerosols. They achieve the highest retrieval accuracy in autumn and winter, while the lowest in summer. The expected research results can provide scientific guidance for the rational use of MODIS and VIIRS AOD products and the improvement of their retrieval algorithms.
2024 Vol. 44 (8): 4211-4229 [Abstract] ( 109 ) [HTML 1KB] [ PDF 11705KB] ( 689 )
4230 Characterizations of fine particle compositions and organic aerosol source analysis during the 2022 epidemic lockdown in a city on the southern edge of the North China Plain
ZHAO Rong-hua, NIU DA-wei, ZHANG Nan, WANG Hui, YANG Wen, WU Li-ping, HAN Bin
To investigate the changes in particulate matter (PM) and organic aerosols at different control stages during the COVID-19 epidemic lockdown in Luohe City, we collected online monitoring data of PM chemical compositions in the study city from 1March to 31 May 2022, and used the positive matrix factorization (PMF) model to analyze the sources of organic aerosols. The results showed that the average mass concentrations of PM2.5 and PM10 during the observation period were 45 and 95μg/m3, respectively. The mass concentrations of PM2.5 compositions showed a decreasing and then an increasing trend in the three time periods before, during, and after the lockdown. In all three periods, the contribution of organic matter was the highest, followed by nitrate. The organic aerosol mass spectrometry data during the observation period were analyzed by PMF, and four types of organic aerosols were identified: more oxidized organic aerosol (MO-OOA), less oxidized organic aerosol (LO-OOA), hydrocarbon-like organic aerosol (HOA) and cooking organic aerosol (COA). The contribution of secondary organic aerosols was higher than that of primary organic aerosols throughout the observation and lockdown periods. In terms of pollutant transport, the three phases of transport were mainly concentrated in the western sector, and the impact of transport was reduced during the lockdown due to the implementation of control measures.
2024 Vol. 44 (8): 4230-4239 [Abstract] ( 111 ) [HTML 1KB] [ PDF 3304KB] ( 804 )
4240 Modeling of PM2.5 in the Yangtze River delta based on geographically weighted random forest
CHEN Yi-min, SU Zhang-wen, CHEN Yi-ping, LIN Zi-peng
This study used Random Forest (RF) and Geographically Weighted Random Forest (GWRF) to train, verify, and test the PM2.5 concentration and data of its driving factors in the Yangtze River delta region from 2003 to 2019 and explore their relationships. The results show that: (1) Compared with the RF model, the GWRF model performs better in training and predicting PM2.5 concentration. The evaluation indicators of the GWRF model are better, and the residual spatial autocorrelation is lower than the RF model. (2) The GWRF model predicts a better PM2.5 concentration distribution in 2019 than the RF model, which is basically consistent with the actual observed concentration distribution. However, overestimation in the north, underestimation in the south, and the area of overestimation are more significant than the underestimation for the two models. (3) The RF model is global in studying the most significant driving factors of PM2.5concentration distribution. In contrast, the GWRF model's interpretation of PM2.5 influence by drought, temperature, temperature difference, wind, and human interference shows a localized effect. On a large scale, this localized effect has practical guidance for preventing and controlling PM2.5. In addition, in the context of global climate warming and spatial heterogeneity of regional climate, integrating drought into PM2.5 prediction and establishing models with localized effects can help environmental regulatory agencies and decision-makers formulate prevention and control measures.
2024 Vol. 44 (8): 4240-4248 [Abstract] ( 165 ) [HTML 1KB] [ PDF 5294KB] ( 1147 )
4249 Analysis of transport path and potential source of polluted particulate matter in five cities of Guanzhong in different seasons
SU Jia, LI Xiao-meng, ZHANG Xin-sheng
Based on the HYSPLIT backward trajectory model and the PSCF and CWT analysis methods in TrajStat, the temporal distribution characteristics and main transport paths of PM2.5 pollution in the five cities of Guanzhong were analyzed using the meteorological data from March 2020~February 2023, and the distribution and contribution of potential source areas affecting the PM2.5 mass concentration in the five cities of Guanzhong in different seasons were discussed. The average PM2.5 concentration was the highest in winter (84.36μg/m3) and the lowest in summer (21.42μg/m3), and the monthly trend showed a "U" shape, and the concentration reached a trough in June~August. The air quality of the five cities was greatly affected by the short-distance transmission air mass in Shaanxi Province in all seasons, which should be related to the blocking of the maneuver by the Qinling Mountains. The seasonal differences in the potential source areas were obvious, the pollutant concentration was the lowest in spring and summer, the distribution range of the main contributing source area was the smallest, the most extensive in winter, the range of WCWT value exceeding 100μg/m3 was large, and the distribution area in the northwest direction and the southern part of Shaanxi Province and its surrounding provinces contributed more to the PM2.5 concentration in the five cities. Air pollution is also affected by topography, and the pollution distribution of Tongchuan, which belongs to the basin topography, is different from that of the other four cities, and the pollution concentration is relatively low.
2024 Vol. 44 (8): 4249-4259 [Abstract] ( 137 ) [HTML 1KB] [ PDF 7714KB] ( 958 )
4260 Impact of summer drought on atmospheric pollutant concentrations and its driving factors
JIANG Feng, WU Bo
Based on the hourly concentrations of PM2.5, PM10, NO2 and SO2 (January to August, 2022) and the meteorological data in 300 prefecture-level cities in China, the influence of summer drought on air pollutants and the driving factors were studied. The findings revealed significant disparities in the cumulative distribution of PM2.5, PM10, NO2, and SO2 concentrations in the Changsha-Zhuzhou-Xiangtan urban agglomeration between drought and normal periods. The cumulative distribution patterns of pollutant concentrations in the cities within the urban agglomeration remained notably consistent. Summer drought was shown to suppress pollution levels of PM2.5, PM10, NO2, and SO2. Specifically, reductions in NO2 concentrations were observed at 45.27μg/m3 (Changsha), 48.53μg/m3 (Zhuzhou), and 13.40μg/m3 (Xiangtan); PM10 at 56.30μg/m3 (Changsha), 55.68μg/m3 (Zhuzhou), and 23.73μg/m3 (Xiangtan); PM2.5 at 36.54μg/m3 (Changsha), 24.48μg/m3 (Zhuzhou), and 37.52μg/m3 (Xiangtan); and SO2 at 2.19μg/m3 (Changsha), 18.51μg/m3 (Zhuzhou), and 4.35μg/m3 (Xiangtan). The study demonstrated that drought could lead to reduced concentrations of PM2.5, PM10, NO2, and SO2 through driving factors such as temperature, atmospheric pressure, wind speed and relative humidity. This research extended the understanding of the impact of drought on air pollution and provided new insights for advancing pollution prevention and control under conditions of extreme weather.
2024 Vol. 44 (8): 4260-4273 [Abstract] ( 108 ) [HTML 1KB] [ PDF 1703KB] ( 617 )
4274 Estimation of ozone background concentration on the Tibetan Plateau based on nonparametric statistical technique
XIE Min-sheng, JI Dong-sheng, YIN Xiu-feng, XIN Jin-yuan, WAN Xin, LI Jian-jun, ZHANG Qiang-gong, BU Duo, CONG Zhi-yuan
The atmospheric background concentration can reflect the degree of pollution and long-term trends on a regional scale. This work was based on the Kolmogorov-Zurbenko (KZ) filtering and Robust Extraction of Baseline Signal (REBS) methods and processed multiple years of continuous near-surface ozone raw observational data from Nam Co Station and Qomolangma Station on the Tibetan Plateau. By optimizing the KZ filter and REBS filtering window and bandwidth, short-term fluctuations in the ozone time series were successfully removed, and signals representing the background concentration of near-surface ozone at both stations were extracted. The results showed that the annual average background ozone concentrations at Nam Co Station and Qomolangma Station were 89.71μg/m3 and 88.98μg/m3 respectively according to the KZ filtering method, and 89.62μg/m3 and 88.52μg/m3 respectively according to the REBS method. The background ozone concentrations obtained by both methods demonstrated good consistency and exhibited similar seasonal variation patterns. The ozone concentration was higher in April-May and lower during the monsoon period. KZ filtering focused more on reflecting long-term trends and seasonal cyclical changes, while REBS performed better during local pollution periods. Both non-parametric statistical methods were effectively applied to the analysis of ozone time series in background regions, providing an important basis for monitoring and controlling ozone pollution.
2024 Vol. 44 (8): 4274-4281 [Abstract] ( 147 ) [HTML 1KB] [ PDF 1832KB] ( 922 )
Water Pollution Control
4282 Nitrogen removal characteristics and bioenhancement effects of aerobic denitrifying bacteria Burkholderia sp. ZH8
LI Yan-li, YANG Lei, ZHANG Zhi-hao, LI Yu-cai, MENG Hong-yan, REN Yong-xiang
Aiming at the problems of complicated process and low denitrification efficiency of traditional biological denitrification treatment of nitrogen-containing wastewater, an aerobic denitrification strain ZH8 was screened from a stable biological filter in the laboratory, and this strain had strong heterotrophic nitrification and aerobic denitrification ability. Strain ZH8was identified as Burkholderia sp. by morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis. The single factor experiments showed that the optimal culture conditions of aerobic denitrification strain ZH8were as follows: carbon source was sodium succinate, C/N was 15, temperature was 30℃, rotational speed was 160r/min and pH was 7~8. In addition, strain ZH8 could not only grow with NH4+-N, NO3--N or NO2--N as a single nitrogen source, but also achieve simultaneous nitrification and denitrification under mixed nitrogen source conditions. According to the whole genome analysis, heterotrophic nitrification of strain ZH8 was ammonium assimilation through glutamate dehydrogenase pathway, and aerobic denitrification pathway was NO3--N→NO2--N→NO→N2O→N2. Carbon metabolism pathway included tricarboxylic acid cycle, glyoxylic acid cycle, glycolysis and pentose phosphate. In the biofilm reactor cultured with pure bacterium ZH8, the reaction could be completed after 8 to 15 days, and the system could maintain efficient and stable nitrogen removal performance, and the removal rates of NH4+-N, NO3--N and TN reached more than 90%. The strain provides a new strain resource for wastewater bio-treatment, which can effectively treat nitrogen-containing wastewater and has practical application value.
2024 Vol. 44 (8): 4282-4291 [Abstract] ( 159 ) [HTML 1KB] [ PDF 3348KB] ( 797 )
4292 Effect of exogenous AHLs on ANAMMOX biofilm process under natural temperature in winter
LUO Rong, LI Jun, GAO Peng, ZHANG Jing, XIE Chao-fan, ZHANG Yi
Maintaining the efficient performance of anaerobic ammonia oxidation (ANAMMOX) biofilm under low-temperature conditions is a great challenge. The effects of two exogenous signaling molecules, hexanoyl homoserine lactone (C6-HSL) and octanoyl homoserine lactone (C8-HSL), on the ANAMMOX biofilm process were examined under the natural temperature in winter. The results showed that the addition of C6-HSL and C8-HSL promoted the nitrogen removal performance of the process under low temperature fluctuation, which increased the total nitrogen removal by 48.09% and 44.36%, respectively, and effectively enhanced the adaptability of ANAMMOX biofilm to the low-temperature environment. Under the low-temperature fluctuation, C6-HSL and C8-HSL regulated the activities of hydrazine dehydrogenase (HDH) (1.77 and 1.57 times higher than that of the control group, respectively), which significantly enhanced the activities of ANAMMOX; promoted the secretion of PN and PS in the extracellular polymers (EPS), especially in the TB-EPS, and altered the hydrophobicity of the secondary structure of proteins, which led to enhanced biofilm adhesion performance ( The OD600 values were enhanced by 55.12% and 68.32%, respectively). In addition, based on 16S rRNA sequencing, C6-HSL and C8-HSL effectively promoted the growth of Candidatus Kuenenia at low temperature and up-regulated the abundance of functional genes related to nitrogen metabolism.
2024 Vol. 44 (8): 4292-4302 [Abstract] ( 108 ) [HTML 1KB] [ PDF 3953KB] ( 671 )
4303 Effect of temperature conversion on continuous operation and microbial community of anaerobic digestion system
TANG Shan-qing, XIE Yan-pei, LIU Zhi-feng, ZHANG Yuan-yuan, ZHANG Xian-sheng, GENG Xue-hai, WANG Mi-er, PAN Yuan, HUANG Xin-yi, TANG Lin
Through 210 days of continuous anaerobic digestion experiment in the same anaerobic digestion system with food waste as fermentation substrate, the conversion of fermentation temperature from medium temperature to high temperature was achieved. In medium temperature fermentation stage, the maximum organic loading rates (OLR) was 6.5kg COD/(m3·d), the average biogas production rate was 658L/(kg COD·d); Methanosaeta (57.0%)、Methanospirillum (10.0%)、Methanomethylovorans (9.2%) and Methanobacterium (19.7%), which formed a symbiotic relationship with hydrolytic acidifying bacteria and homoacetogenesis to achieve efficient methanogenic process, were included in the dominant methanogens. After 35 days’ heating process, the medium temperature fermentation system smoothly converted into high temperature system. In high temperature fermentation stage, the maxium OLR was 5.0kg COD/(m3·d), and the average biogas production rate was 480L/(kg COD·d); Methanoculleus (96.2%) became dominant methanogenic bacteria, and formed an interacting relationship with syntrophic hydrogen-producing bacteria and syntrophic acetate oxidation bacteria, which jointly promoted H2utilization and methanogenic process. However, obvious acidification trend and reduced gas production efficiency appeared in later stage of high-temperatures system. It was inferred that the activity of methanogens was inhibited with highly enriching of hydrolytic acid-producing bacteria, resulting the imbalance of organic acids production and utilization and the system collapse. Therefore, online temperature conversion of anaerobic fermentation system was technically feasible, but the performance and stability of high temperature fermentation system were lower than that of medium temperature fermentation system.
2024 Vol. 44 (8): 4303-4313 [Abstract] ( 132 ) [HTML 1KB] [ PDF 1291KB] ( 1192 )
4314 Characterization of extracellular polymer substances and acyl-homoserine lactones of sulfur-based autotrophic denitrification microbial community under high nitrate loading
XU Wei-yi, HUANG Kai-wen, LIU Chong, SHEN Fei, WANG Shuo, LI Ji
Sulfur-based autotrophic denitrification (SADN) was influenced by hydraulic retention time (HRT) and influent NO3--N concentration. By progressively shortening the HRT and increasing the influent NO3--N concentration, the nitrogen removal limit of the process was explored. Simultaneously, the changes in extracellular polymeric substances (EPS) and signal molecules acyl-homoserine lactones (AHLs) were analyzed, along with the evolution of microbial community structure in this process. During the transition from an HRT of 4.1h to 1.0h, SADN bacteria rapidly adapted to the environment. When the HRT was 1.0h and the influent NO3--N concentration was 40mg/L, the system achieved a TN removal rate of 99.74%, with a denitrification load as high as 958.53mg/(L·d). In this process, the increase in EPS concentration was mainly driven by TB-PN and TB-PS, while the increase in AHLs concentration was primarily led by C4-HSL. In comparison to shortening the HRT, raising the influent NO3--N concentration significantly increased the C4-HSL concentration, leading to a gradual trend towards an unstable state in the sludge structure. C6-HSL, the predominant AHL in the system, exhibited substantial growth in stages G4 and G7, reflecting a self-regulation by the microorganisms following the weakening of the system's denitrification capability. Analysis of the microbial community composition indicated that system operation and nitrogen load variations drove the domestication selection of microbial communities. In the reduced HRT group, norank_f_ Pleomorphomonadaceae of Proteobacteria played a primary role as the dominant bacterial genus, providing substrates for denitrification bacteria to sustain system stability. Following the increase in NO3--N concentration, UKL 13-1, Simplicispira, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, and Thermomonas gradually evolved into dominant bacterial genera, all crucial microorganisms with denitrification capabilities.
2024 Vol. 44 (8): 4314-4325 [Abstract] ( 190 ) [HTML 1KB] [ PDF 2096KB] ( 1268 )
4326 Study on nitrogen and phosphorus removal in SPNPR-A system based on short-cycle regulation
LI Dong, WANG Qin-yuan, MAO Zhong-xin, QI Sai-yue, ZHANG Jie
In this study, a simultaneous partial nitrification and phosphorus removal-anaerobic ammonia oxidation (SPNPR-A) system with short-cycle and low-concentration nitrite (NO2--N) was established. The SPNPR system operates in anaerobic/aerobic mode, and the NO2--N concentration in the system was limited for a brief duration to restrict nitrite oxidizing bacteria (NOB), simultaneously enriching ammonia oxidizing bacteria (AOB) and polyphosphate accumulating organisms (PAOs), and finally realizing synchronous nitrogen and phosphorus removal. The results showed that the NOB activity could be effectively inhibited by maintaining the NO2--N concentration in the SPNPR system at about 10mg/L for a short-cycle. After 70days, the nitrite accumulation rate (NAR) of the two short-cycles of SPNPR system reached 90.40% and 88.93%, respectively, and the average removal rates of total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) in SPNPR-A system were 87.45%, 84.30% and 94.26%, respectively. At the 60th day, specific ammonia oxidation rate (SAOR) and specific oxygen utilization rateAOB(SOURAOB) were 8.47mgN/(gMLVSS·h) and 12.71mgO2/(gMLVSS·h), respectively. Specific nitrate production rate (SNPR) and specific oxygen utilization rateNOB(SOURNOB) were 0.82mgN/(gMLVSS·h) and 0.41mgO2/(gMLVSS·h), respectively. The results of high-throughput sequencing showed that, the abundance of AOB genera Nitrosomonas (6.46%) and Nitrosospira (0.64%) in SPNPR system was much higher than that of NOB genera Nitrospira (0.14%) and Nitrobacter (0.01%) on the 70th day, and at the same time, the phosphate accumulating organisms of Candidatus_Accumulibacter (1.61%) and Tetrasphaera (0.89%) were gradually enriched, so that the SPNPR-A system underscored the robust performance of synchronous nitrogen and phosphorus removal.
2024 Vol. 44 (8): 4326-4335 [Abstract] ( 134 ) [HTML 1KB] [ PDF 1382KB] ( 827 )
4336 Influence of illumination strategy in anaerobic stage on the performance of bacterial-algal symbiosis system in A/O mode
LI Dong, GONG Wei-min, LI Shuai, CHAI Chen-xv, ZHANG Jie
In order to investigate the effects of different illumination strategies in the anaerobic stage on the bacterial-algal symbiotic system, four groups of sequence batch reactors (SBR) were set up to operate in an anaerobic/aerobic (A/O) mode, in which the anaerobic stage of R1 was illuminated with 8000lx; R2, R3 and R4 divided the anaerobic stage into A1 and A2. There is no illumination in the A1stage, and the illumination intensity in the A2stage respectively are 0, 3000, 5000lx. The results of this research revealed that R3 and R4 with weak illumination added at the late anaerobic stage could rapidly enriched the microalgae, which led to the formative bacterial-algal symbiotic granular with dense structure, good settling performance, better carbon, nitrogen and phosphorus removal, and the secretion of more extracellular polymers (EPS). Among them, R3 had the best effect of phosphorus removal, and the removal rate of total phosphorus (TP) reached 95.87%. According to the analysis of typical cycle, the phosphorus release at the end of anaerobic stage was proportional to the chlorophyll a (Chl-a) content under weak illumination condition; the ability of R3 to release phosphorus is the strongest, and its phosphorus concentration at the end of anaerobic stage reaching 43.73mg/L; the high-phosphorus environment formed in the A2 stage was able to stimulate the growth of microalgae, and its Chl-a content reached 6.13mg/gVSS at the late stage of the operation. High-throughput sequencing showed that the prokaryotic of R3 were successfully enriched phosphorus accumulating bacteria (PAOs) centered on Candidatus_Accumulibacter with an abundance of 11.18%; the total abundance of microalgae in the eukaryotes reached 84.29%, of which the abundance of Halochlorella was as high as 42.85%, suggesting that the addition of weak illumination (3000lx) to the high-phosphorus environment in the late anaerobic stage could stimulate the growth of microalgae without affecting the growth of the PAOs, thus form a symbiotic granular with microalgae and PAOs as the core, which provides technical support for the deep treatment of wastewater.
2024 Vol. 44 (8): 4336-4346 [Abstract] ( 114 ) [HTML 1KB] [ PDF 1324KB] ( 635 )
4347 Photocatalytic degradation of RhB by CdS with Cd vacancy defects
WU Yong, YAO Qing
To enhance the photocatalytic degradation performance of CdS, Cd1-xS with Cd vacancy defects was synthesized through a hydrothermal method and was applied to the photocatalytic degradation of Rhodamine B (RhB). The results showed that under visible- light irradiation for 40min, the photodegradation rate of RhB by Cd1-xS reached 98.1%, with a degradation rate constant k = 0.08649min-1, which was significantly higher than that of CdS. The quenching experiments of free radicals indicated that ·O2- is the main active species during the photocatalytic degradation of RhB by Cd1-xS. UV-DRS, XPS, and EPR characterization results demonstrated that the introduction of Cd vacancies widened the bandgap of Cd1-xS to inhibit the absorption of visible light, and proved that the enhancement of the photocatalytic activity was not due to changes in the band structure. Density functional theory calculations combined with PL results revealed that the introduction of Cd vacancies led to an asymmetric local electron density in CdS to promote hole transport and charge carrier separation, thereby significantly enhancing the photocatalytic activity of Cd1-xS.
2024 Vol. 44 (8): 4347-4354 [Abstract] ( 98 ) [HTML 1KB] [ PDF 1800KB] ( 832 )
4355 Study on granule size control strategies in a novel continuous flow system for Anammox
LI Dong, LI Song-yue, DONG Yi-wen, JIANG Peng-fei, LI Shuai, ZENG Hui-ping, ZHANG Jie
This study, employed a novel, patented twin-reactor self-recirculating system to explore the granule size control strategies and its controlling mechanisms of anaerobic ammonium oxidation (Anammox) granular sludge based on granules size recirculation approach. By adjusting internal recirculation locations, the strategy aimed to control the size of granules through introducing sludge of varying sizes into regions with high substrate concentration and mechanical shear. The result demonstrated that this strategy effectively increased granule size, and maintained it within an appropriate range. Furthermore, it enhanced sludge concentration, settling characteristics, and nitrogen removal performance. Specifically, recirculating larger granules proved to be highly effective, keeping the size of granular sludge within the optimal range of 0.5~1.6mm, with a median size of 948μm, SVI of 35.6mL/g, and an enhanced total inorganic nitrogen (TIN) removal efficiency of 88.59%. Analysis of extracellular polymeric substances (EPS) revealed that proteins (PN) in the tightly bound EPS (TB-EPS) played a crucial role in granule size control. Stratification experiments revealed that PN in the outer layer of the sludge primarily influenced settleability, while PN in the TB-EPS of the inner layer strengthens the granule structure. High-throughput sequencing showed a significant increase in the abundance of anammox bacteria (AnAOB) Candidatus Kuenenia, mainly located in the inner layers of the sludge granules. These findings have significant implications for the engineering application of anammox granular sludge technology.
2024 Vol. 44 (8): 4355-4365 [Abstract] ( 124 ) [HTML 1KB] [ PDF 1229KB] ( 644 )
4366 Effect of two co-habitat bacteria on the recruitment of dormant Microcystis aeruginosa cells
ZOU Wan-sheng, Mo Ping, WANG Zhi, LIU Liang-guo
Both benthic bacteria and dormant M. aeruginosa cells (DMCs) are important members of aquatic ecosystems. In our previous research work, one strain of algae-inhibiting bacterium (Sphingobacterium kitahiroshimense 10CT, strain H1) and one strain of algae-promoting bacterium (Bacillus zhangzhouensis DW5-4T, strain H2) were isolated simultaneously from the same aquaculture fishpond. Recruitment experiments were conducted to unveil the combined impact of the two bacteria on the DMCs recruitment. Strain H1 and H2 at different bacterial ratios were mixed with DMCs and embedded into sediments. The experiments were conducted at temperature 15°C and 25°C, a photoperiod of 12h light: 12h dark, and a light intensity of 15μmol/(m2·s) for 21 d. The results showed that when the bacterial ratio was less than three, the concentration of soluble extracellular polysaccharides (SPS) of DMCs in bacterial groups significantly reduced compared with the control group (sterile group), while there was no significant difference in capsular extracellular polysaccharides (CPS) and photosynthetic efficiency (Fv/Fm) of DMCs (P>0.05). The SPS concentration decrease did not affect Fv/Fm, and the strains H1 and H2 significantly improved the recruitment rate of DMCs by secreting three metabolites. When the bacterial ratio was greater than five, the SPS, CPS, and Fv/Fm in the bacterial groups were significantly lower compared with the control group (P<0.05). The decrease of CPS concentration inhibited the photosynthetic efficiency (Fv/Fm) of DMCs, and under high bacterial ratio condition the strains H1 and H2 synergistically reduced the recruitment rate of DMCs by reducing the photosynthetic efficiency (Fv/Fm) of DMCs and secreting two metabolites that effectively inhibited DMCs recruitment (the recruitment rate of DMCs under pure metabolite was higher than that of the bacterial groups). Interestingly, field qualitative experiments confirmed that the different bacterial ratio of strains H1 and H2 significantly affects the recruitment rate of DMCs, and the experimental results provide new ideas for predicting the recruitment rate of DMCs in early spring and a new approach for early preventing formation of M. aeruginosa blooms.
2024 Vol. 44 (8): 4366-4379 [Abstract] ( 111 ) [HTML 1KB] [ PDF 1570KB] ( 958 )
4380 Behaviors and mechanisms of cadmium/lead adsorption by natural bamboo fibers modified with succinic acid
ZHANG Xiao-feng, LI Xiang-yu, WANG Xin, HU Jing-xiang, MA Zhen-yu, TAN Feng-liang, HE Lu
After pretreatments of alkalization and acidification, the natural bamboo fibers underwent esterification reaction with succinic acid to produce modified bamboo fibers. Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis indicated that, after modification, the electronegative carboxyl and ester groups in bamboo fibers increased, and their microstructure changed from dense and flat to wrinkled and porous simultaneously. The adsorption experiments showed that the modified bamboo fibers achieved significantly higher adsorption rates of cadmium (Cd) and lead (Pb) than natural bamboo fibers (up to 47.37% and 44.57%, respectively), and could also be applied to a wider pH value range. The adsorption of Cd and Pb by modified and unmodified bamboo fibers conformed to both Langmuir and Freundlich thermodynamic models.Besides, after modification the maximum adsorption capacity (Qm) of the bamboo fibers for Cd and Pb increased from 8.9687mg/g and 11.5075mg/g to 26.1780mg/g and 32.3625mg/g respectively, indicating that the modification process of succinic acid increased the adsorption sites of the bamboo fibers, and thus improved their adsorption capacity of Cd/Pb, which can provide a new idea for the modification and upgrading of biosorbent materials.
2024 Vol. 44 (8): 4380-4388 [Abstract] ( 121 ) [HTML 1KB] [ PDF 1126KB] ( 834 )
4389 Treatment of nitrogen-containing wastewater by dissimilatory nitrate reduction to ammonium coupled with anaerobic ammonium oxidation
ZHAO Shuo, WANG Chao, YANG Meng, QIAO Sen
To investigate the feasibility and long-term performance of simultaneous removal of ammonium (NH4+) and nitrate (NO3-) in wastewater by anaerobic ammonia oxidation (anammox) bacteria, batch, inhibitor, isotopic and long-term reactor experiments were conducted based on the intracellular carbon-dependent dissimilatory nitrate reduction to ammonium (DNRA) of anammox bacteria. In 12h batch experiments, NH4+ and NO3- were simultaneously converted to N2 with anammox biomass concentration of 4500mg/L, and the total nitrogen removal efficiency was 93.49%. In the experiment of acetylene inhibition (inhibiting the process of generating hydrazine from NH4+and nitric oxide in the anammox reaction), 17.01mg N/L of NH4+ was detected, and the contribution rate of anammox bacteria to NO3-removal was 85.88%. After the addition of penicillin G (an inhibitor for most heterotrophic denitrifying bacteria), NO3- could still be removed. Both 29N2 and 30N2 was always detected from the very beginning in the 15N isotope tracing experiment, and the former was 1.4 folds higher than the latter. In the long-term experiment, the average NH4+ and NO3- concentrations of effluent were 1.18 and 2.86mg N/L respectively, reaching an average total nitrogen removal efficiency of 92.26%. These results suggested that NH4+ and NO3-could be simultaneously removed by endogenous DNRA coupled with normal anammox metabolism, further promoting the application of anammox-based processes for nitrogen-contained wastewater removal.
2024 Vol. 44 (8): 4389-4399 [Abstract] ( 137 ) [HTML 1KB] [ PDF 3353KB] ( 974 )
4400 Performance analysis of iron-carbon autotrophic denitrification for efficient removal of nitrate from anammox effluent
XING Wei, LI Long-sheng, GAO Dao-qing, Zhang Ze-xi, ZHOU Guang-xin, YAO Hong
The investigation of nitrate removal from anammox effluent using the iron-carbon autotrophic denitrification process, involved the examination of continuous operation, iron precipitation transformation, and microbial community structure. The study revealed the coupling mechanism between the iron-carbon carrier and biofilm, demonstrating the efficient removal of nitrate through the iron-carbon autotrophic denitrification process. At HRT of 16.6h, the total nitrogen (TN) removal efficiency of anammox effluent was found to be (90.0±4.7) %. Conversely, the TN removal rate of anammox effluent was (82.2±1.4) % at HRT of 13.3h. During Stage I, Fe3O4 was identified as the predominant form of iron precipitation within the biofilm, whereas in Stage III, there was a decrease in Fe3O4 and an increase in the density of FeOOH type iron precipitation. Throughout the iron-carbon autotrophic denitrification process, the prevalence of Dechloromonas, the primary denitrifying bacterium in the initial sludge inoculum, experienced a notable decrease. Conversely, there was an enrichment of autotrophic denitrifying bacteria and iron-converting bacteria, exemplified by the rise in relative abundance of Thermomonas from 0.70% on day 43 to 4.51% on day 120.
2024 Vol. 44 (8): 4400-4406 [Abstract] ( 151 ) [HTML 1KB] [ PDF 1424KB] ( 903 )
Solid Waste
4407 Characteristics and influence mechanisms of chlorine existence in municipal solid waste/waste PCB co-incineration bottom slag
SHI Hong-jie, SHEN Dong-sheng, LONG Yu-yang, GU Fo-quan
The co-incineration of municipal solid waste (MSW) with general industrial solid waste is recognized as a crucial development trend in the waste incineration industry. However, the impact of co-incineration on chlorine distribution within incineration slag remains poorly understood. This study, using a typical industrial printed circuit board (PCB) as the experimental material, investigates the co-incineration process of MSW and waste PCBs. The migration behavior, chemical forms, and long-term stability of chlorine in slag samples under varying waste compositions were determined. The research examines the migration behavior, chemical forms, and long-term stability of chlorine in slag samples under varying waste compositions. The findings demonstrate that the high-temperature decomposition of glass fibers in waste PCBs results in the retention of volatile chlorine in the slag due to the fibers’ large specific surface area. This leads to an overall increase in total chlorine content within the slag, with the proportion of plastics in the waste mixture significantly influencing this process. The water-soluble chlorine content in the co-incinerated slag samples ranged from 50 to 70wt%. Dynamic leaching results revealed that the residual chlorine rate in most slag samples was below 40%. However, as the proportion of waste PCBs increased, the chlorine residue ratio in the slag rose, peaking at 45.6%. This indicates that co-incineration reduces chlorine leaching from the slag.
2024 Vol. 44 (8): 4407-4414 [Abstract] ( 144 ) [HTML 1KB] [ PDF 1663KB] ( 669 )
4415 Effect and the mechanism of hydrochars on methane production of cornstalk digestion
GENG Tao, ZHAO Li-xin, YAO Zong-lu, SHEN Rui-xia, YU Jia-dong, LUO Juan
In this study, different types of hydrochars were prepared from corn straw and cotton straw at different temperatures to clarify the effects of preparation conditions such as temperature, materials on its physicochemical properties and the promotion effects of hydrochars addition on corn straw anaerobic digestion were explored further. The results showed that the carbonization degree of corn straw was higher than that of cotton straw at the same preparation temperature. The oxygen-containing functional groups of hydrochars such as O-H and C-O were decreased when the reaction temperature was elevated but it was conducive to the improvement of carbonization degree, the construction of surface pore structure and the microsphere morphology at the higher temperature. The hydrochars were added to the corn straw anaerobic digestion system, and the corn straw hydrochar prepared at 180℃ had the most significant promotion effect which increasing the cumulative methane production and the maximum methane production rate by 13.74% and 12.06%, respectively. Meanwhile, it contributed to the degradation of VFA and stabilized the variance of pH in the anaerobic digestion system. Microbial analysis showed the acidobacterium such as Firmicutes and Synergistota as well as hydrogenotrophic methanogenesis such as Methanosarcina and Methanospirillum were enriched to accelerate the methane production. It may be related to the abundant oxygen-containing group of hydrochar.
2024 Vol. 44 (8): 4415-4424 [Abstract] ( 142 ) [HTML 1KB] [ PDF 1941KB] ( 774 )
4425 Performance evaluation for the treatment of municipal sludge and kitchen waste via black solider fly larvae
TIAN Wei-ping, XING Yu, WANG Zhou-qiang, YUN Wei-wei, JIAN Yu-ling, XIE Yan-dong
In the present study, black soldier fly larvae (BSFL) were used to co-treat municipal sludge and kitchen waste mixed at different proportions. Feasibility of co-treatment of both wastes was investigated through evaluating the growth and development, and quality (i.e., nutrition and heavy metals) of BSFL. The high survival rate (>93%) of BSFL in all treatments was confirmed. The dry weight (189~299g) of BSFL decreased as the proportion of municipal sludge increased. The proportions of crude fat and protein of larvae accounted for 7.73%~26.81% and 22.80%~36.65%, respectively. Remarkable waste reduction rate of > 57% after the treatments was observed along with high larvae biomass (13.8%~23.9%). As for larvae feces, the contents of organic matter and total nutrition (N, P, and K) reached 60.86%~ 95.22% and 4.20%~6.58%, respectively. Furthermore, the contents of Cr, Cd, As, Pb and Cu in larvae feces decreased. These findings indicate that BSFL feces are as excellent raw materials made for organic fertilizer. Therefore, BSFL treatment technology is regarded as an feasible approach for valorization of municipal sludge and food waste.
2024 Vol. 44 (8): 4425-4431 [Abstract] ( 144 ) [HTML 1KB] [ PDF 432KB] ( 1366 )
4432 Pyrolysis of medical waste: A review
LI Tang-wei, LI Jian, YAN Bei-bei, CHEN Guan-yi
The basic characteristics and treatment status of medical waste in China were reviewed in this work, and a comparative analysis among different disposal technologies has been performed. Pyrolysis was proposed for medical waste treatment, and the pollution emission as well as the control strategy were investigated. The emerging pyrolysis technologies integrated with medical waste treatment were introduced, and the design of pyrolysis facility was discussed. Furthermore, the future direction of medical waste pyrolysis was analyzed based on the technology development, policies and regulations.
2024 Vol. 44 (8): 4432-4445 [Abstract] ( 138 ) [HTML 1KB] [ PDF 751KB] ( 1082 )
4446 Effect of dumping protocol and consolidation on shear strength of highly saturated abandoned-clay
XU Hui, WANG Jin-nan, LI Sheng-zhi, WANG Lu-nan, ZHAN Liang-tong
In this paper, 24 sets of large-scale combined tests of consolidation and direct shear were conducted on the representative abandoned-soil samples that obtained from a foundation engineering site in Hangzhou. They were performed to investigate the shear strength behavior of highly saturated clay during consolidation under three loading protocols of instantaneous, stepped and linear stress. The results show that: the highly saturated clay had immediate compression after the application of overburden stress and the compression increased with an increase in the stress; when the final stresses of three loading protocols were the same, the final settlement was relatively close; the shear curves were strain hardening, and the initial tangent modulus and final shear stress both increased with the increase of consolidation degree or overburden stress; the loading protocol had a certain effect on the initial tangent modulus, but had a smaller effect on the final shear stress; the shear strength increased linearly with the growth of consolidation degree, and the magnitude of increase was significant with increasing stress; when the overburden stress and consolidation degree were consistent, the shear strength was essentially similar under three loading protocols. Based on the above findings, a shear strength prediction model of highly saturated clay considering consolidation was established and its reliability was verified using the data from this study and relevant literature. The model analysis results show that: with the growth of consolidation degree, the shear strength envelope intercept increased linearly, while the bending degree decreased linearly. In the highly saturated abandoned-clay dumping projects, the model established in this paper can be used to predict the shear strength of the soil under consolidation process of different dumping protocols.
2024 Vol. 44 (8): 4446-4454 [Abstract] ( 117 ) [HTML 1KB] [ PDF 1208KB] ( 815 )
4455 Research on modified calcium based adsorbents for in-situ CO2 capture through pyrolysis
GU Chun-han, SU Ming-xue, LI Ning, ZHU Bing
Addressing the challenge of high in-situ adsorption temperature in solid waste pyrolysis, we developed a series of calcium-based solid adsorbents by incorporating various minerals into natural limestone. Experimental investigations on the single adsorption and cyclic adsorption of CO2 by these calcium-based solid adsorbents revealed that the adsorbent doped with 10% montmorillonite exhibited stable cyclic adsorption characteristics and a substantial adsorbent capacity, achieved a maximum CO2 adsorption ratio of 71.52%. Even after 10cycles, the adsorption capacity remained at 43.77%, concurrently elevated the heat value of pyrolysis gas to 14kJ/g. Consequently, the calcium-based adsorbents doped with 10% montmorillonite demonstrated effective CO2 capture and contribute to the enhanced calorific value of pyrolysis gas in solid waste co-pyrolysis.
2024 Vol. 44 (8): 4455-4461 [Abstract] ( 123 ) [HTML 1KB] [ PDF 1281KB] ( 688 )
Soil Pollution Control
4462 Constructing soil cadmium discharge inventory for source analysis—a case study in copper smelter
SHENG Yi, XUE Wei-zhen, YING Di-wen, WU Jun, LI Ye, SHI Pei-li, ZHAO Ling
This study took a copper smelting plant in East China as an example, and used the “four emission pathways” functions to quantitatively describe the flux of Cd entering soil through “waste gas deposition, wastewater discharge, solid waste leaching, and run-off and leakage”. Combining the waste gas deposition model (AERMOD), the distribution of Cd carried by waste gas was calculated inside and outside the site boundary, and the contribution of each pathway to soil Cd pollution in the site was clarified. The results indicated that during the production period from 2000 to 2002, Cd was mainly emitted through waste gas deposition (1411kg, 50.05%) and solid waste leaching (1327kg, 47.05%), while the impact of wastewater and run-off as well as leakage pathways was small (a total of 81.74kg, 2.90%). However, only 0.68kg Cd in the waste gas was deposited inside the site, which only account for 0.05% of the overall Cd pollution in the soil of this site, while soil Cd in the site was mainly contributed by the solid waste leaching pathway. The spatial discharge inventory showed that soil Cd pollution was mainly distributed in production areas such as the stacking area and waste gas treatment area. The research results have important significance for strengthening the fine source control of the smelting industry, and the method proposed in this article can be extended to the source analysis of other industries and multiple pollutants.
2024 Vol. 44 (8): 4462-4474 [Abstract] ( 114 ) [HTML 1KB] [ PDF 3489KB] ( 702 )
4475 Characterization of phosphorus adsorption and risk of phosphorus release from black soil by returning straw to the field
WEN Fang-yue, ZHANG-Yu, CHEN Shang-cai, WANG Yu-jun
By analyzing the effects of straw no-tillage (MG), straw mulching (FG) and straw deep turning (SF) on soil physicochemical properties and soil phosphorus adsorption characteristics, the effects of soil physicochemical properties on phosphorus adsorption characteristics were studied, and the release risk of phosphorus in soil was further analyzed. The results showed that the contents of soil organic matter and available phosphorus increased, and the bulk density of soil decreased after straw returning. Compared with no-tillage, the adsorption capacity of soil phosphorus was reduced by 20.1% after straw mulching and returning to the field, and the adsorption capacity of soil phosphorus after straw deep turning and returning to the field was reduced by 35.0%.The DPS (phosphorus saturation) in black soil under the three different tillage modes were MG: 0.3%, FG: 4.0%, SF: 10.2%, PSI (phosphorus uptake index) were MG: 41.14, FG: 40.04, SF: 36.09 (mg P/(100g))/(mmol/L), and ERI (phosphorus release risk index) were MG: 0.7%, FG: 9.9%, and SF: 28.3%, respectively. Straw mulching and deep straw returning can significantly increase soil organic matter, reduce soil phosphorus adsorption capacity, and improve soil phosphorus effectiveness, but also improve soil phosphorus adsorption saturation, which can easily cause the risk of phosphorus loss.
2024 Vol. 44 (8): 4475-4483 [Abstract] ( 127 ) [HTML 1KB] [ PDF 798KB] ( 967 )
4484 Interactions between lepidocrocite and heavy metals: Research progress from interfacial processes to environmental behaviors
FAN Cong, FANG Jun-ran, LI Xiao-fei, GUO Chu-ling, SHEN Yu, LU Gui-ning, MEI Yuan-fei, DANG Zhi
The biogeochemical cycle of iron plays a key role in the migration and transformation processes of soil materials, especially in the environmental behavior of heavy metals. Lepidocrocite is a common metastable iron (hydroxyl) oxide that typically found in soils with seasonal redox alternations. It has a large specific surface area and high surface activity, and can drive soil material circulation. This article takes the stability of lepidocrocite as a link, to explain the evolutionary patterns of its three different roles of as an original mineral, precursor (intermediate product) and final product in different transformation pathways. The interaction mechanism between formation/transformation of lepidocrocite and fate of heavy metals was systematically discussed from the perspective of biogeochemical cycles. The impact of typical environmental factors (such as pH, oxyanions, dissolved organic matter and microorganisms) on the stability of lepidocrocite and the occurrence forms of heavy metals was focused on. Future research trends include the transformation mechanism of iron minerals in complex environments, the microscopic reaction mechanism of heavy metals at the mineral-water interface, and the regulation of environmental factors on the fate of heavy metals. These studies aim to provide solutions for pollution remediation by regulating the iron cycle and understanding the occurrence status of heavy metals. Additionally, they offer insights for predicting the environmental behavior of heavy metals under the influence of iron minerals.
2024 Vol. 44 (8): 4484-4495 [Abstract] ( 137 ) [HTML 1KB] [ PDF 751KB] ( 1696 )
4496 Characteristics and source identification of heavy metal pollution in shallow topsoil in Yinchuan City
LAI Juan-juan, YANG De-yu, LIU Liang, MA Fan, WANG Yan-yu
To comprehensively assess the status of heavy metal contamination in the topsoil of a city in Northwest China, this study focused on the 0~2cm surface layer in Yinchuan City. The Single Factor Index, Nemerow Pollution Index, and Potential Ecological Risk Index were utilized to gauge heavy metal pollution and potential ecological hazards. The spatial distribution patterns of soil heavy metals were examined using the inverse distance weighted interpolation method. Correlation analysis and principal component analysis were employed to identify pollution sources. Subsequently, the research expanded to include an analysis of topsoil heavy metal contamination in several key cities across Northwest China, with a discussion on the regional implications of the findings. The study revealed that concentrations of Ni and Cr in Yinchuan's shallow topsoil were relatively low, whereas Cu, Pb, and Zn demonstrated varying levels of accumulation, with Cd exhibiting significant enrichment. The average values of Cr and Ni were lower than the background values of Ningxia soil, which were 0.95 and 0.73 times the background values, respectively. The average values of Cd, Cu, Pb, and Zn elements were higher than the background values of Ningxia soil, which were 1.70 times, 1.00 times, 1.08 times, and 1.09 times, respectively. The pollution levels, according to the Single Factor Index, were ranked as Cd>Zn>Pb>Cu>Cr>Ni, and the average Nemerow Pollution Index indicated a mild pollution level. Ecological risk assessments showed minor risks associated with Cd, Cr, Cu, Ni, Pb, and Zn, and the comprehensive potential ecological risk index suggested an overall slight risk. In Yinchuan, shallow topsoil concentrations of Cr and Ni were predominantly originated from natural sources, while Cd, Cu, Pb, and Zn were mainly attributed to transportation and agricultural activities, with Cd also being impacted by industrial pollution. Heavy metals in urban soils across Northwest China exhibited some degree of enrichment, yet accumulation levels were not excessive, and the primary contributors were transportation, industry, and natural sources. The significant presence of Cd in the soils of Northwest China was concerning and warranted close scrutiny with respect to industrial, agricultural, and transportation developments.
2024 Vol. 44 (8): 4496-4506 [Abstract] ( 113 ) [HTML 1KB] [ PDF 2855KB] ( 1042 )
4507 Optimization and product characteristics of cyanobacteria-based plant growth stimulants by acid and thermal hydrolysis
LI Yu-zhi, HUANG Kai-wen, ZHU Ge, XU Yan-juan, WANG Shuo, LI Ji
This study utilized cyanobacteria as a raw material, subjecting it to acid-thermal hydrolysis. The optimal hydrolysis conditions for cyanobacteria were analyzed, and the safety of applying cyanobacteria-based plant stimulants to soil was evaluated using Pij、Igeo、RI and human exposure health risk assessment. Results demonstrated that using 2% oxalic acid for hydrolysis, exploiting the chelation effect of oxalic acid on heavy metals, and further adjusting the pH to 0.8 with sulfuric acid while maintaining a 24-hour hydrolysis constituted the optimal acid-thermal hydrolysis conditions to minimize environmental risks associated with cyanobacteria-based plant stimulants. The Pij、Igeo、RI of cyanobacteria-based plant stimulants prepared under various conditions indicated negligible risks, absence of pollution, and low-risk levels, respectively. Moreover, the calculated human carcinogenic and non-carcinogenic risks associated with plant stimulants were found to be below the safety thresholds of 10-6 and 1. In addition, using a semi-continuous acid-thermal hydrolysis system to enhance the concentration of beneficial substances in cyanobacteria-based plant growth stimulants, it was observed that after 3~4cycles of hydrolysis enrichment, the levels of nutrients (N, P, and K) in the plant growth stimulants stabilized at 3942, 290.45, and 421.7mg/kg, respectively. Furthermore, 2-(5H)-furanone and pyrrole compounds, classified as bio-stimulants, continued to accumulate in the plant growth stimulants, reaching levels of 29.5646 and 11.261mg/kg, respectively. These substances can effectively promote plant growth and inhibit pathogens. Moreover, alkaloids and phenolic compounds, considered as allelopathic substances, were degraded during hydrolysis, and subsequently alleviating the inhibitory effects on plant growth.
2024 Vol. 44 (8): 4507-4519 [Abstract] ( 116 ) [HTML 1KB] [ PDF 2384KB] ( 864 )
Environmental Ecology
4520 Vertical distribution characteristics of soil organic matter and its response to short-term vegetation succession
SHEN Ya-ting, ZHANG Wei, HE Xiao-jia
Typical soil profile samples were collected from depths ranging from 0 to 110cm in Beijing and Yunnan, China, over a period of approximately ten years of vegetation succession. The vertical distribution characteristics of soil organic carbon stable carbon isotope ratios (δ13Corg), total organic carbon, organic carbon density, O/C ratio, and C/N ratio in soil organic carbon were analyzed to investigate the response of soils at different depths to vegetation succession. The objective was to reveal the vertical distribution characteristics and stability patterns of soil organic matter. The study found that soil δ13Corg varied significantly across different regions and depths. Notably, the δ13Corg patterns in the deep soil profiles of Beijing and Yunnan were inversely related, with vegetation succession impacting the δ13Corg change rate at various soil depths. In the Beijing area, the δ13Corg change rate decreased with increasing soil depth following vegetation succession. Furthermore, the vertical distribution characteristics of total organic carbon, organic carbon density, soil organic matter polarity, and C/N ratio, as well as their responses to vegetation succession, differed markedly. Some typical profiles indicated that vegetation succession could enhance total organic carbon and soil organic matter polarity in deeper soil layers. The findings suggest that under the influence of varying latitudes, different vegetation covers, and distinct soil physical and chemical properties, the characteristics of soil organic matter are closely linked to distribution depth and short-term vegetation succession. These insights may provide a crucial basis for understanding the dynamic interactions between vegetation succession and the carbon cycle.
2024 Vol. 44 (8): 4520-4529 [Abstract] ( 154 ) [HTML 1KB] [ PDF 1536KB] ( 912 )
4530 Pore-scale mechanisms of DNAPL oxidative remediation in a microfluidic device
WANG Ze-jun, YANG Zhi-bing, HU Ran, CHEN Yi-Feng
To elucidate pore-scale mechanisms governing the coupled process of multiphase flow, chemical reactions, and phase transformations during the oxidation remediation of dense non-aqueous phase liquids (DNAPLs), we conducted 48microfluidic experiments to investigate the trichloroethylene (TCE) oxidation by potassium permanganate (KMnO4). The results show that when KMnO4 concentration exceeded 3g/L, the manganese dioxide (MnO2) solid products during TCE oxidation formed a "solid wall", which hindered the contact between MnO4- and TCE. Under such conditions, the residual TCE oxidation proceeded only via the slow penetration of KMnO4 solution through the MnO2 wall, where limited MnO4- was converted to Mn2+. As Mn2+ diffused out of the MnO2 wall, it was re-oxidized to MnO2 solid phase, creating a negative feedback loop and significantly reducing remediation efficiency. At KMnO4 concentrations below 3g/L, the MnO2 solid products were able to attach to the channel surfaces, permitting continuous reaction between MnO4- and TCE, thereby resulting in a higher remediation efficiency. The introduction of phosphate significantly suppressed the formation of MnO2 solid products and improved remediation efficiency, with an optimal KMnO4 concentration for TCE remediation determined to be 1~2g/L.
2024 Vol. 44 (8): 4530-4538 [Abstract] ( 162 ) [HTML 1KB] [ PDF 4622KB] ( 954 )
4539 Analysis of crganic carbon burial characteristics in mangrove sediments on Maoyan Island
YU Yang, SHUI Bo-nian, LV Cong-cong, LI Bin, LI Xue-li, WEI Zhen, HU Cheng-ye
The northern mangrove wetlands of Maoshan Island were taken as the study area to investigate the characteristics and sources of organic carbon burial in the sediments. The sedimentation rate (SAR), organic carbon density, burial rate (OCAR), potential sources of organic carbon, and contribution rates were analyzed using the constant sedimentation rate model based on radiogenic isotopes (210Pb). The sedimentation rate in the Maoshan Island mangrove wetlands was approximately 1.8cm/year. The sediments were mainly composed of silt and clay, with particle size remaining stable with depth. A good correlation was observed between excess 210Pb activity and depth, indicating a stable sedimentary environment. The average organic carbon density of the sediments was 0.66g/cm3, and the burial rate was 120.01g/(m2·a). The distribution characteristics of stable carbon and nitrogen isotopes, combined with the multivariate mixing model (IsoSource), showed that the sources of organic carbon in the sediments were mainly a mixture of marine and terrestrial origins, with marine sources accounting for 50.3%, terrestrial sources for 33.4%, and tree sources contributing 16.3%. Surface sediments were primarily influenced by terrestrial and tree inputs, with the highest contribution rate from tree sources reaching 46.4%. The composition of mangrove vegetation and the time since forest establishment were important factors affecting the burial of organic carbon in the sediments.
2024 Vol. 44 (8): 4539-4546 [Abstract] ( 128 ) [HTML 1KB] [ PDF 1278KB] ( 1247 )
4547 Predicting CO2+O2 in-situ leaching process in physico-chemical heterogeneous sandstone-type uranium ore using a cDC-GAN-based proxy model
LIU Dian-guang, YANG Yun, ZHANG Yong, QIU Wen-jie, WU Jian-feng, WANG Jin-guo, WU Ji-chun
A CO2+O2 in-situ leaching uranium reactive solute transport model based on physical processes requires high-resolution grids to capture the spatial variability of medium physical-chemical parameters and the multi-process coupling characteristics of advection-dispersion-chemical reactions. This often faces significant computational challenges. Traditional surrogate models encounter precision and curse of dimensionality issues when predicting high-dimensional data spatial distributions. In this paper, a conditional Deep Convolutional Generative Adversarial Network (cDC-GAN) is proposed as a surrogate modeling component for multi-input image to output image regression. The mapping relationship between high-dimensional physical-chemical heterogeneous fields (permeability fields and uranium mineral grade fields) and uranium leaching concentration distribution fields is established. The median structural similarity index in the training and test sample sets exceeds 0.98, making it a viable alternative to numerical models of the CO2+O2 in-situ leaching process for sandstone-hosted uranium deposits. The cDC-GAN surrogate modeling is not constrained by the underlying physical model, thereby providing a general framework for parameter identification, uncertainty analysis, global sensitivity analysis, and simulation optimization design of complex reactive solute transport models.
2024 Vol. 44 (8): 4547-4556 [Abstract] ( 146 ) [HTML 1KB] [ PDF 4090KB] ( 668 )
4557 Spatiotemporal changes of ecosystem services and their response to urbanization in Xinzhou City
XIE Ming-wei, RAN Li, JIA Wen-zhen, ZHOU Hui-di, WANG Xiang-rong
In order to investigate the spatial and temporal changes of ecosystem services (ESs) in Xinzhou City and analyze the response of ESs to urbanization, three urbanization indicators and four ESs indicators were selected based on six periods of land use data from 1995 to 2020, while ESs were assessed with the help of the InVEST model and the Revised Universal Soil Loss Equation (RUSLE). Moreover, K-means clustering was used to identify ecosystem services bundles (ESB). Besides, Pearson correlation coefficient was used to analyze the trade-offs and synergies among ESs and their responses to urbanization. The results showed that: (1) Land use types in Xinzhou City were dominated by grassland, arable land and forest, with construction land expanding by 280.7km2, forest increasing by 1201.4km2, grassland increasing by 511.4km2, and arable land and water area decreasing in the period from 1995 to 2020. There was a greater shift from arable land to grassland and from grassland to forest. (2) Construction land, GDP and population continued to grow, and 2005~2015 was a period of rapid urbanization.1995~2020 the food provision steadily improved, carbon stock significantly increased after 2015, habitat quality firstly increased and then decreased, soil retention firstly decreased and then increased. (3) The area of grassland-based functional complex ecosystem services bundles accounted for 51.4%, with mainly synergistic relationships among ESs, and negative correlation between habitat quality-urbanization and soil retention-urbanization. The results of this study can provide scientific basis for land management and ecological protection in Xinzhou City.
2024 Vol. 44 (8): 4557-4566 [Abstract] ( 109 ) [HTML 1KB] [ PDF 7019KB] ( 883 )
4567 Seasonal and spatial pattern of greenhouse gas concentration and emission flux in small water body of wetland park
XU Mei-li, MA Jiao-jiao, LI Jia-hong, YI Xiao-qing, GAO Chang-jun
This study selected Shenzhen Baguang wetland park as the study area. A one-year sampling program was conducted within three types of water bodies, i.e., ditches, ponds and estuaries. Measured data were used to investigate the seasonal and spatial pattern of greenhouse gas and its driving factors in the typical small water body within highly urbanized area. The results showed that the average concentrations of dissolved CO2, CH4, and N2O in the water were (54.30±49.55), (0.89±1.45), and (0.0038±0.0007) μmol/L, respectively. The average fluxes of CO2, CH4, and N2O emission were (113.94±424.19), (1.48±3.84), and (0.0044±0.0176) mg/(m2·h), respectively, implying a source of greenhouse gas to atmosphere. The emission potential of CO2 from these small water bodies was much higher than coastal waters, lakes and other waters, and was the main contributor (85.57%) to the global warming within the entire wetland park water. From the perspective of spatial and temporal heterogeneity, greenhouse gas concentrations and fluxes showed a pattern of warm season (August) > cool season (January, April, December), ditches > ponds and estuaries, and were higher near the middle of the wetland park. Salinity, pH, ammonium nitrogen, nitrate, electrical conductivity, chemical oxygen demand, and total organic carbon were the critical environmental factors contributing to differences in dissolved greenhouse gas concentrations in the water. EC was the critical environmental factor influencing greenhouse gas fluxes.
2024 Vol. 44 (8): 4567-4575 [Abstract] ( 134 ) [HTML 1KB] [ PDF 1777KB] ( 940 )
Develpment of a beautiful China: Emerging Contaminants
4576 Study on monitoring widespread concerned emerging contaminants under the construction of the Beautiful China
ZHAO Shu-li, CHEN Shao-kun, YU Xiu-hao, WANG Hai-lin
In the process of constructing the Beautiful China, monitoring and treating emerging contaminants have gradually become one of the important tasks in China's ecological environment protection. Currently, emerging contaminants that are currently receiving widespread attention include persistent organic pollutants, endocrine disruptors, antibiotics, and microplastics. Based on the latest progress in the research on emerging contaminants at home and abroad, this article provides a brief overview of the environmental distribution and monitoring analysis of some key emerging contaminants. It is also discussed that the development direction for emerging contaminants monitoring technology, aiming to provide assistance for the construction of Beautiful China.
2024 Vol. 44 (8): 4576-4587 [Abstract] ( 167 ) [HTML 1KB] [ PDF 1000KB] ( 1430 )
4588 Redox mediator-enhancing ferrate(VI) oxidation of emerging contaminants
SONG Li-xian, ZHENG Cheng-zhi, YU Yong-qiang, ZHANG Jing, MA Jun
The most representative redox mediator, tetramethylpyrazine oxide (TEMPO), was used to investigate the efficacy and mechanism of its enhanced degradation of emerging contaminants by ferrate (Fe(VI)). The results showed that the system could remove 73% of sulfamethoxazole (5μmol/L) within 120 seconds. Through in-depth analysis, it was found that TEMPO+ and Fe(V)/Fe(IV) are key active species in the system. Additionally, the effects of TEMPO concentration, initial pH and common components (humic acid, inorganic anions) in the actual water on the reaction system were investigated. Given the difficulties in recycling and potential secondary pollution of homogeneous catalysts, the 4-amino-TEMPO@SiO2 heterogeneous catalysts were further developed. The prepared heterogeneous catalyst demonstrated significant enhancement effects on phenolic, quinolone, and tetracycline pollutants, with the most notable effects on phenol and tetracycline, which can be completely removed in just 20 seconds.
2024 Vol. 44 (8): 4588-4598 [Abstract] ( 128 ) [HTML 1KB] [ PDF 2456KB] ( 889 )
4599 Characteristics and driving factors of microplastics in surface water environment of China
CHEN Qin-win, WANG Peng, DING Ming-jun, ZHANG Hua, NIE Ming-hua, HUANG Gao-xiang
In order to elucidate the occurrence characteristics and driving factors of microplastics in the surface water environment of China, this study based on published literature collected microplastic characteristics, experimental methods, and geographical environmental information from 1944 sampling sites. The research showed that the abundance of microplastics in the surface water environment of China ranged from 0 to 204183 items/m3, and in sediment from 0to 79931items/kg. The abundance of microplastics exhibited significant spatial heterogeneity in the surface water environment of China. In water bodies, the abundance of microplastics was highest in inland river basins (13185.77items/m3), and the lowest was found in the Southeast rivers basin (2678.07items/m3). In sediment, the Huai River basin had the highest level of microplastic abundance (2145.61items/kg), while the Hai River basin had the lowest abundance (294.82items/kg). The morphologies of microplastics in water and sediment were mainly fibrous (58.29%/47.21%) and fragments (23.20%/30.03%), respectively. Small microplastics (<0.5mm) constituted the majority based on particle size (59.61% /62.76%). Transparent microplastics accounted for the largest proportion in terms of color (30.18% and 28.17%, respectively). The main materials of microplastics were polyethylene (PE) (25.49%/27.78%) and polypropylene (PP) (25.36%/22.69%). The characteristics of microplastics in water bodies are primarily influenced by natural environmental factors, with abundance, shape, and color features all significantly correlated with environmental factors such as temperature and precipitation. In contrast, the characteristics of microplastics in sediments are mainly influenced by socio-economic factors, with abundance, shape, and particle size features significantly correlated with socio-economic environmental factors such as GDP, night light intensity, and population density. Significant differences in microplastic characteristics, including abundance, morphology, color, and polymer types, are observed under different experimental treatments. Path analysis using partial least squares indicates that the influence of experimental treatments on microplastic characteristics is comparable to the geographical environment. The lack of standardized experimental methods makes it difficult to compare and validate different experimental results, highlighting the urgent need for the establishment of standardized experimental procedures to minimize the impact of experimental treatments on the observation of microplastic characteristics.
2024 Vol. 44 (8): 4599-4609 [Abstract] ( 128 ) [HTML 1KB] [ PDF 2549KB] ( 1365 )
4610 Oxidation performance and mechanism of bisphenol A over supported nascent MnO2
YIN Hao-chen, QIN Xi-ran, ZHANG Zhe-rui, MA Ming-yu, ZHAO Chun-ke, LU Jin-suo, WANG Gen
Mineral supported nascent MnO2 (S-MnO2) with porous structure was prepared via reducing KMnO4 by plant poly-phenol (e.g., tannic acid) anchored on the surface of airstone. The oxidation performance and mechanism of endocrine disruptors (such as bisphenol A, BPA) over S-MnO2 was investigated, and stability of S-MnO2 in complicated water matrix was studied. Due to the porous net-work like structure, the recoverable S-MnO2 exhibited good performance toward the oxidation of BPA. When the dosage of S-MnO2 was 4.0g (containing 7.08μmol MnO2), 94% of BPA was removed in 60min, which was 4.5 times higher than that over the same amount of powdery nascent MnO2. Mechanism studies revealed that Mn(III) and Mn(IV) were both participated into the oxidation of BPA, and Mn(III) was essential to the rapid removal of BPA. The removal of BPA was mainly ascribed to the single electron transfer reaction, which enabled good resistance to complex surroundings like anions, cations and natural organic matters. S-MnO2 was relative stable for BPA removal in consecutive runs and could be facile regenerated via the oxidation by KMnO4, revealing a promising potential for further application.
2024 Vol. 44 (8): 4610-4620 [Abstract] ( 108 ) [HTML 1KB] [ PDF 2659KB] ( 834 )
4621 Potential impact of polyethylene on the growth of pakchoi (Brassica campestris L.): Endophyte effects
YU Fang-ming, GAO Yu, CHEN Yu-yuan, FU Ming-yue, TANG Chi-jian, MO Cui-ju, LI Yi
In the current study, pakchoi (Brassica campestris L.) was selected and pot experiments were conducted to investigate the potential impact of polyethylene microplastic (PE-MPs) addition at different size and levels on the growth and physiological and biochemical variations of pakchoi. PE exposure resulted in a significant decrease in height and weight of pakchoi (P<0.05), with decreased by 86.8% and 60.3%, respectively, at PE particle size of 0.5 µm, addition level of 0.5% (w/w). Meanwhile, PE exposure resulted in a significant decrease in photosynethics pigments concentrations in leaves of pakchoi (P<0.05). Two-way ANOVA results indicated that the PE particle size has greater impact on the growth of pakchoi and the variations of photosynethics pigments concentrations. In addtions, PE exposure resulted in a significant decrease in both Shannon and ACE indices for bacteria (P<0.05), and a significant increased of Simpson index for fungi (P<0.05). Moreover, the relative abundance of Proteobacteria and Ascomycota increased, while the relative abundance of Actinobacteriota decreased under different PE additions. SEM images showed that PE-MPs occurred mostly in the xylem and cell walls of the root cortical tissues of pakchoi. Two-way ANOVA results indicated that the PE particle size has greater impact on oxidative stress contents. PE exposure causing serious structural and functional damage and membrane lipid peroxidation damage of pakchoi, and leading to a decrease in pakchoi biomass.
2024 Vol. 44 (8): 4621-4631 [Abstract] ( 121 ) [HTML 1KB] [ PDF 3438KB] ( 816 )
4632 Catalytic oxidation of carbamazepine by Fe, Co/NPs@GO bimetallic three-dimensional particle electrode
ZHOU Zi-xuan, ZHUO Qiong-fang, Ghulam Yasin, XIE Shui-bo
The Fe-Co bimetallic particle electrodes (Fe,Co/NPs@GO) were synthesized by the freezing/carbonization method. And the degradation performance of the Fe,Co/NPs@GO bimetallic three-dimensional particle electrode system for CBZ was optimized by adjusting the precursor ratio of Fe and Co. The effects of current density and PMS dosage on CBZ degradation were examined. It was found that a removal rate of 99.5% for CBZ (1mg/L) could be achieved within 30min under the conditions of 0.15g/L Fe,Co/NPs@GO (Fe:Co=1:1), 3mmol/L PMS, and a current density of 20mA/cm2. The addition of electrocatalytic conditions to the pure catalyst activation of PMS system resulted in an increase in the removal rate of CBZ by approximately 37%. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis confirmed that •OH and 1O2 are the primary active species responsible for CBZ degradation, and the degradation mechanism of CBZ in the electrocatalytic coupling three-dimensional particle electrode activation of peroxymonosulfate (PMS) system was deduced. The recycling experiment of the particle electrode demonstrated that the Fe, Co/NPs@GO particle electrode possesses good catalytic stability and reusability.
2024 Vol. 44 (8): 4632-4640 [Abstract] ( 119 ) [HTML 1KB] [ PDF 1930KB] ( 975 )
4641 Physicochemical factors and dominant bacterial groups affecting antibiotic degradation in chicken manure aerobic compost
HUANG Fei-fei, LIU Jian-kun, WANG Xiao-ming, LEI Meng-long, TIAN Xiao-mei, CUI Yan-ru, ZHANG Da-lei
Taking chicken manure as raw material, the influence of EM microbial agent on the key dominant bacterial groups controlling the degradation of antibiotics were studied in the compost simulated by adding oxytetracycline and tylosin to simulate antibiotic residues. The objective is to explore the bioenhancing mechanism of antibiotic removal in aerobic composting. The experiment was carried out consisting of four treatments, that is, OCK (oxytetracycline), OTK (oxytetracycline +EM bactericide), TCK (Tylomycin + EM bactericide), TTK (Tylomycin + EM bactericide. The amounts of added antibiotics and EM microbial agent were 100mg/kg and 5% of the total mass, respectively. The results showed that the residue of antibiotics had little effect on compost maturation, and all treatments could reach the maturation standard. The composting temperature exceeded 60℃ for more than 6days, the pH value ranged from 8.5 to 9.0, the EC was 3~3.5mS/cm. The removal of both antibiotic mostly happened at high temperature stage, When the removal rates of antibiotics were correspondingly OCK: 71.63%,OTK: 76.40%,TCK: 93.86%,TTK: 92.95%. The EM microbial agent accelerated the degradation of antibiotics, especially for oxytetracycline, which could increase the degradation rate of oxytetracycline by 5 times and that of Tylomycin by 2.24 times. At mature stage, aerobic compost effectively removed the antibiotic residues, with higher antibiotic removal rates of four treatments, OCK 89.97%, OTK 91.32%, TCK 99.99%, TTK 99.99%. pH value is identified as a key physicochemical factor affecting the degradation of oxytetracycline and tylomycin, which was negatively correlated with the content of both antibiotics, so proper adjustment of the pH was conducive to faster degradation of antibiotics. The dominant bacterial groups conducive to oxytetracycline degradation mainly include Planifilum, Thermobifida, Bacillus and Paenibacillus, with Relative abundance (RAs) were 0.24%~8.76%, 2.70%~10.91%, 11.38%~26.16%, and 1.95%~4.56%. While Thermobacillus and Bacillus was helpful for degradation of Tylomycin with RAs were 7.19%~39.09% and 41.70%~44.29%, respectively. Bacillus can promote the degradation of oxytetracycline and tylosin.
2024 Vol. 44 (8): 4641-4651 [Abstract] ( 97 ) [HTML 1KB] [ PDF 2098KB] ( 940 )
4652 Performance and mechanism of photocatalytic tetracycline degradation by Bi2WO6/MIL-101in water
CAI Feng-ying, XU Yu-hang, LONG Hao-ran, YUAN Yu-xin, ZHANG Yu-qing, HE Qiu-xiang, Lü Jian
The Bi2WO6/MIL-101composite photocatalysts were synthesized via a hydrothermal method to facilitate the degradation of tetracycline (TC) under visible light. Research findings demonstrated that the TC degradation efficiency of Bi2WO6 under visible light was significantly enhanced following the dense growth of BWO nanosheets on the surface of MIL-101. Furthermore, the structurally optimized BWO/MIL-101-40exhibited a TC degradation efficiency of 85.9% within 60minutes, with a reaction rate constant approximately 1.4 times that of Bi2WO6 and 3.1times that of MIL-101. Additionally, BWO/MIL-101 displayed consistent and robust photocatalytic performance in neutral and alkaline conditions. Band structure analysis revealed the formation of type II heterojunctions between Bi2WO6 and MIL-101, contributing to effective photoelectron-hole separation. Quenching experiments and electron paramagnetic resonance (EPR) tests indicated superoxide radical (•O2-) and holes (h+) as the primary active species in this particular photocatalytic system.
2024 Vol. 44 (8): 4652-4660 [Abstract] ( 127 ) [HTML 1KB] [ PDF 1845KB] ( 917 )
Environmental Toxicology and Health
4661 Prediction of acute toxicity of organic chemicals on rare minnow using machine learning
MO Jun-chao, YAO Hong-wei, CAO Feng
Acute toxicity data of organic chemicals were collected for rare minnows (Gobiocypris rarus). A machine learning method was developed to predict the acute toxicity of organic chemicals specially for rare minnow, using existing acute toxicity data for zebrafish (Danio rerio) and fathead minnow (Pimephales promelas). A binary model was used to determine whether the organic chemical have acute toxicity to rare minnow; if yes, a regression model was then utilized to predict the median lethal concentration LC50. Different machine learning models were compared, and it was found that the support vector machine performed the best in the binary classification model, with the accuracies of 92.4% in the training set and 88.6% in the test set, respectively. The elastic net regression method demonstrated the best performance in the regression model. The adjusted R2 of the training set was 0.87, while the adjusted R2 of the test set was 0.75. The cross-validation coefficient Q2 LOO of the left-one-out method was 0.52, and the external validation coefficient Q2 EXT was 0.71. The two models exhibited commendable accuracy, robustness, and predictive capability. The first ionization potential and n-octanol water partition coefficient had a greater effect on the classification, and the regression prediction results were more heavily influenced by the topological charge. The above results offer a precise and efficient prediction method for assessing the acute toxicity of the rare minnow, an endemic model organism in China, significantly expediting the environmental risk assessment of organic chemicals.
2024 Vol. 44 (8): 4661-4673 [Abstract] ( 129 ) [HTML 1KB] [ PDF 869KB] ( 970 )
4674 Bioaccumulation and trophic transfer of PAEs and APs in aquatic organisms
LIU Yin-e, LUO Xiao-jun, HUANG Chen-chen, WANG Lu, MAI Bi-xian
In this study, 7 phthalate esters (PAEs) and 13 alternative plasticizers (APs) in aquatic organisms from the disused e-waste dismantling site and freshwater fish in the Beijiang River in Qingyuan City, Guangdong Province were detected to investigate their bioaccumulation and trophic transfer. The total concentrations of PAEs and APs in aquatic organisms from the disused e-waste dismantling site and freshwater fish in the Beijiang River were 20~974ng/g ww and 1.25~181ng/g ww, 264~370ng/g ww and 27~62ng/g ww, respectively. Di-butyl phthalate and di-(2-ethylhexyl) phthalate were dominant PAE pollutants, while bis (2-ethylhexyl) terephthalate was predominant AP pollutant. The concentrations and compositions of PAEs and APs significantly varied among different aquatic organisms in the e-waste dismantling site, which were closely related to their different feeding habits, growth stages, and metabolic capacity. There is no significant difference between the mud carp and tilapia in the Beijiang River, which were mainly related to their similar habitat environment, feeding behaviour, and lipid content. Both the concentrations based on wet weight and lipid weight for dimethyl phthalate were significantly and positively correlated with nitrogen isotope (δ15N) values, and trophic magnification factors (TMF) were 1.65 and 1.88, respectively. In addition, the concentration based on lipid weight for diphenyl phthalate was significantly and positively correlated with δ15N values, and TMF was 1.91.
2024 Vol. 44 (8): 4674-4682 [Abstract] ( 214 ) [HTML 1KB] [ PDF 722KB] ( 665 )
4683 Assessment of selenium exposure and health risks among residents in areas with different selenium levels
HUANG Lei, YANG Qin-yi, LI Chen, QIN Li-qiang, SHI Ke-xin, PENG Xiang-wen, WANG Zhang-min
In order to clarify the selenium nutritional status of the population from different selenium levels, 76local residents (exposed population) and 116foreign tourists from Suzhou, Wuxi, Changzhou and Shanghai (control population) were recruited to participate in a questionnaire survey in Wentang Town to collect their basic information, living habits, dietary frequency, etc. The selenium content of the soil, water, atmospheric particulate matter and food samples from Wentang and Linhu Towns was analyzed according to the classical health risk assessment method of the U.S. Environmental Protection Agency (USEPA). The selenium exposure levels, exposure pathways and health risks were analyzed according to the classic four-step health risk assessment method of the U.S. Environmental Protection Agency (EPA). The average daily dietary selenium intake of local residents was significantly higher than that of foreign tourists, and the highest contributors to the dietary selenium intake of the residents in both areas were eggs and livestock and poultry meat. The average selenium exposure of local residents was also significantly higher than that of foreign tourists, with diet being the main exposure route. In this study, the average daily selenium intake of the residents living in Wentang met the standard, and there was no non-cancer risk due to excessive selenium intake, while 88.76% of the foreign tourists had insufficient selenium intake, which suggests that the residents living in non-selenium-rich areas need to improve selenium intake by adjusting the dietary structure and the source of the diet.
2024 Vol. 44 (8): 4683-4689 [Abstract] ( 180 ) [HTML 1KB] [ PDF 613KB] ( 939 )
4690 Advances inmicrobial degradation of poly (butylene adipate terephthalate) plastic
HU Ying, YANG Yu-ting, CHEN Shan-shan, LUAN Tian-gang
With the intensification of the global plastic pollution, the rate and mechanism of microbial degradation of Poly (butylene adipate terephthalate) (PBAT), a representative of biodegradable plastics, have received increasing attention. Here we compare the degradation patterns of PBAT in water, soil, and compost environments, analyze the effects of different factors on the microbial degradation PBAT, summarizes the PBAT-degrading bacteria that have been screened so far and compares their degradation speeds, and elucidate the PBAT modification mechanism and modification products at both extracellular and intracellular levels. Finally, we proposed future research directions from the aspects of research on influencing factors, unification of PBAT degradation indicators, construction of microbial community, and exploration technology of PBAT degradation mechanism.
2024 Vol. 44 (8): 4690-4699 [Abstract] ( 194 ) [HTML 1KB] [ PDF 891KB] ( 819 )
Environmental Impact Assessment and Management
4700 The theory of the people's livelihood of Eco-environment and the task of development in the new era
WANG Jin-nan, ZHANG Xiao-jing, XUE Qiang, LU Lu, LI Hong-wei, HU Yi, ZHANG Jie, QIN Chang-bo
As a basic public service, ecological environment has become an important part of the people's livelihood system in China. However, so far, the connotation of the concept of the people's livelihood of Eco-environment is not clear, and the research points such as theoretical logic and task path are scattered, and academic consensus has not been formed. In order to establish the overall framework of the people's livelihood of Eco-environment from theoretical framework, strategic path to task system, this paper carries out theoretical traceability analysis, clarifies its related concepts, development routes and research directions in many fields such as humanities and social sciences, natural sciences and economics. and summarizes the relationship between the people's livelihood of Eco-environment and the inheritance of Chinese traditional culture and Marxist view of nature, the evolutionary relationship with environmental justice, and the verification relationship with human welfare research and the realization of the value of ecological products. This paper initially analyzes the connotation of the people's livelihood of Eco-environment theory by combining research on ecosystem service supply and Maslow's hierarchy of needs theory. This paper summarizes the theoretical points such as the internal relationship between ecological environment and people's well-being and the characteristics of The Times. According to the needs of the people's livelihood of Eco-environment construction in the new era, the development approach of the people's livelihood of Eco-environment has been established with the three dimensions of quantity, quality and efficiency as the core. This paper puts forward the main tasks such as people-centered improvement of the ecological environment quality, setting up value supply zones for ecological products, and releasing ecological welfare benefits. In order to promote the systematic development of the people's livelihood of Eco-environment research, and provide a reference for the direction of the people's livelihood of Eco-environment construction in the new era.
2024 Vol. 44 (8): 4700-4708 [Abstract] ( 126 ) [HTML 1KB] [ PDF 759KB] ( 880 )
4709 Screening method and application of groundwater pollution remediation technology for coking sites in China
WU Fen qi, ZHANG Wei-hong, DONG Jun, ZHU Kai, MA Si-yao, WANG Lin, HU Wei, LI Yan
The selection of appropriate remediation technologies for groundwater pollution of coking-contaminated sites is a huge challenge. To address this problem, the "China Coking Site Pollution Remediation Database" was constructed in this study and a screening process for groundwater pollution remediation technology for coking sites was proposed. The screening system was constructed from four dimensions: technical applicability, society and environment, remediation cost, and remediation duration. Besides, the analytic hierarchy process and entropy weight methods based on a genetic algorithm were adopted to calculate the indicator weight of the remediation technology screening system, and the Monte Carlo algorithm was applied to simulate site information to reduce the uncertainty of the obtained site information and make the evaluation results more scientific. Finally, the model was applied to the screening of groundwater pollution remediation technology of the coking site in China, and the results showed that the scores of pump and treat technology ranked the top two in four dimensions and the total score ranked the first (21.6680). Thus, pump and treat technology was recommended for the remediation which was consistent with the actual site application. In all, this study provided a methodological basis and theoretical reference for the selection of groundwater pollution remediation technologies for coking sites in China.
2024 Vol. 44 (8): 4709-4718 [Abstract] ( 134 ) [HTML 1KB] [ PDF 1347KB] ( 819 )
4719 Collaborative impact of environmental judiciary on the multi-entity environmental responsibility
LI Xiao-qing, LI Yi, LIU Jia-qi
Utilizing the environmental litigation data gathered by the Intermediate People's Court and the Procuratorate spanning from 2008 to 2021, the study was conducted to examine the impact and underlying mechanism of environmental justice on the synergistic collaboration in fulfilling environmental responsibilities among multiple stakeholders. Through the application of the fixed effect model and the mediation effect model, the heterogeneity of this phenomenon was further scrutinized. It was observed that environmental justice played a pivotal role in fostering such collaboration, facilitated primarily by the “linkage effect” of governmental environmental law enforcement, the “deterrent effect” of corporate environmental governance, and the “guiding effect” of public environmental concern. A subsequent in-depth analysis indicated that this promotional effect of environmental justice on collaborative environmental responsibility was particularly pronounced in regions with higher levels of digitization, superior regional rule of law environments, and predominantly in the eastern and central regions.
2024 Vol. 44 (8): 4719-4730 [Abstract] ( 189 ) [HTML 1KB] [ PDF 583KB] ( 825 )
4731 Measuring the recyclability and eco-design of typical tires
ZHAO Shu-jie, XU Jun-yuan, ZENG Xian-lai
The rapid growth and widespread consumption in the automotive industry have led to a surge in waste tire generation. Waste tires are a significant concern due to their environmental and resource impacts. Improving the recyclability and eco-design of tires is essential to address this problem. This study aims to tire recyclability using an innovative model based on statistical entropy and a hierarchical determination rule. This rule considers the differences between the tires' original state and their post-recycling state, as well as the predominant treatment and disposal methods. We applied this model to assess five different tire applications. The results indicate that tire recyclability ranges from approximately 82% to 93%, with the highest recyclability found in truck tires, followed by car tires, van tires, bus tires, and off-road vehicle tires. These findings can inform the design of tire recycling processes and energy recovery efforts. The developed recyclability method may significantly contribute to the eco-design of tires and promote energy saving and emission reductions in the tire industry.
2024 Vol. 44 (8): 4731-4736 [Abstract] ( 116 ) [HTML 1KB] [ PDF 658KB] ( 849 )
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