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  Current Issue
 
2022 Vol.42 Issue.4,Published 2022-04-20
Air Pollution Control
Water Pollution Control
Solid Waste
Soil Pollution Control
Environmental Microbiology
Environmental Ecology
Environmental Impact Assessment and Management
Environmental Toxicology and Health
Carbon Emission Control
Air Pollution Control
1489 Differences of biogenic volatile organic compound emissions from urban forests in Nanjing and Beijing
YUAN Xiang-yang, XU Yan, DU Ying-dong, FENG Zhao-zhong
Total emissions of BVOCs from typical cities (e.g. Beijing and Nanjing) in south and north China in 2015 were estimated by using the data of forest resource check, hourly meteorological observation and G95model algorithms based on light and temperature dependences. The study found that the total BVOC emissions in Nanjing were mainly derived from Slash pine, Quercus and Poplars. Among the dominant tree species in Beijing, Quercus, Poplars and Chinese pine had the highest BVOC emissions. From the total emissions, the VOC emissions from forest sources in Beijing were 2 to 3times higher than those of Nanjing, which were 72114.1t/a and 28025.3t/a, respectively. By contrast, the area-based BVOCs emission intensity in Nanjing was 1.6 times higher than those of Beijing. The seasonal changes of all types of BVOC emissions in both Beijing and Nanjing were unimodal, with the highest emissions in summer and the lowest in winter, while there was little difference in emissions between spring and autumn. In Nanjing, middle-aged forests and near-mature forests were the main emission sources of BVOCs. However, middle-aged forests and young forests were the main emission sources in Beijing. The contribution to total BVOC emissions in each tree age class was mainly determined by its leaf biomass, but the type of dominant tree species in each tree age class also affected the emission of BVOCs to a certain extent.
2022 Vol. 42 (4): 1489-1500 [Abstract] ( 374 ) [HTML 1KB] [ PDF 814KB] ( 2111 )
1501 Estimation of BVOCs emissions from Beijing, Tianjin and Hebei from 2000 to 2020 and its temporal and spatial distribution characteristics
QI Hao-yun, WANG Xiao-qi, CHENG Shui-yuan, CAI Bin, LI Ao-zhe
In order to study the emission and temporal and spatial distribution characteristics of volatile organic compounds (BVOCs) from natural sources in Beijing, Tianjin and Hebei regions in recent 20 years, based on five periods of China's land use data obtained from satellite remote sensing interpretation in 2000, 2005, 2010, 2015 and 2020, this paper calculates and obtains the emission and emission composition of BVOCs from cities and counties in Beijing, Tianjin and Hebei, At the same time, the temporal and spatial distribution of BVOCs emission in Beijing Tianjin Hebei region in recent 20 years is analyzed The results show that the average total emission of BVOCs in Beijing Tianjin Hebei region in recent 20 years is 764000 T/A, of which the average total emission of Hebei Province, Beijing and Tianjin are 591100T/A, 152900T/A and 20000t/a respectively; According to the analysis of emission composition, the average total emission of ISOP is 168000T/A, accounting for 21.99% of the total emission, the average total emission of TMT is 296200T/A, accounting for 38.77% of the total emission, and the average total emission of OVOCs is 299700T/ A, accounting for 39.23% of the total emission According to the analysis of emission time characteristics, the BVOCs emission in Beijing Tianjin Hebei region is the lowest in winter and the highest in summer The spatial distribution of BVOCs emissions is closely related to land use types and vegetation distribution. There are significant differences in the contribution of BVOCs emissions from different land use types. The average BVOCs emissions from forest land, cultivated land and grassland in Beijing Tianjin Hebei region in recent 20 years are 603300T/A, 127800T/A and 23100T/a respectively, accounting for 78.90%, 16.79% and 3.04% of the total emissions respectively The spatial emission distribution of BVOCs in Beijing Tianjin Hebei region is obviously different, and the overall emission in the north and northeast is significantly higher than that in the South and Southeast This study can provide research ideas for the calculation of BVOCs, and provide relevant basic data for air pollution control in Beijing, Tianjin and Hebei.
2022 Vol. 42 (4): 1501-1509 [Abstract] ( 413 ) [HTML 1KB] [ PDF 1711KB] ( 1209 )
1510 Sizing and source characterization of particulate organic nitrates based on long time-of-flight aerosol mass spectrometer (Long-ToF-AMS) in Shenzhen
YU Guang-he, CAO Li-ming, ZHU Qiao, WANG Chuan, HUANG Xiao-feng
In this study, a long time-of-flight aerosol mass spectrometer (Long- ToF-AMS) was applied to characterize particulate organic nitrates (pON) during March 30th to April 17th in 2021 at Shenzhen. Using cross-validation estimated methods, we calculated pON accounting for 5.08%~11.00% in total OA. The diurnal pattern with nighttime higher mass loading for pON and the best correlation with less-oxidized oxygenated OA (LO-OOA) at night indicated that pON formation might be more associated with nighttime fresh secondary formation. The high-resolution size distribution of pON showed they contained a substantial fraction of smaller size particles, further confirming the contributions from primary aerosols or newly formed secondary aerosols at night. Additionally, the potential precursors for pON formation was further explored based on comparison analysis between mass spectrum of our ambient data and the laboratory generated pON using different precursors. The results implied that volatile organic compounds (VOCs) emitted from biogenic sources and biomass burning were potential precursors for pON formation in Shenzhen.
2022 Vol. 42 (4): 1510-1517 [Abstract] ( 280 ) [HTML 1KB] [ PDF 837KB] ( 1258 )
1518 The characterization of greenhouse gas emission from road traffic sources in Shenzhen
ZHANG Ming-di, HE Dong-yi, GU Tian-fa, SUN Tian-le, LIN Xiao-yu, HUANG Xiao-feng, HE Ling-yan
In this study, three greenhouse gases (CO2, CH4, and N2O) and one conventional gas (CO) were observed at a roadside station in Shenzhen from September, 2019 to July, 2020. The average concentration of CO2, CH4, N2O, and CO was (430.8±6.1)x10-6, (2318.5±137.9)x10-9, (332.6±1.6)x10-9, and (333.4±121.2)x10-9, respectively. Seasonal variation of CO2 and CO were high in winter and low in summer, Seasonal variation of CH4 and N2O were high in autumn and low in summer. The high concentration in autumn and winter is due to the long-distance transmission of fossil fuel emissions during the heating period, and the low concentration in summer is mainly due to the reduction of long-distance transmission sources and the enhancement of sinks such as plant photosynthesis and photochemical reactions. The diurnal variation of CO2 concentration showed a two-peak and one-valley pattern, which was mainly affected by plant photosynthesis and morning and evening traffic peak; The diurnal variation of CO concentration showed a two-peak pattern, which was mainly affected by the morning and evening traffic peaks. The diurnal variation of CH4 andN2O concentration was high at night and low at day, which was mainly affected by daytime photochemical reaction. Among them, the concentration of CO2 and CO is more sensitive to the emission of traffic sources. In addition, this study compared the COVID-19 lockdown period in 2020 with the same period in 2021, and the results showed that the concentration of CO2, CH4, N2O, and CO decreased by 3.1%, 10.6%, 0.5% and 13.9%, respectively, indicating that traffic control can play an important role in reducing urban greenhouse gas emissions.
2022 Vol. 42 (4): 1518-1525 [Abstract] ( 283 ) [HTML 1KB] [ PDF 1021KB] ( 1223 )
1526 Study on effective density of size-resolved particles and the influencing factors in Shenzhen
ZHENG Jin-yi, PENG Yan, WEI Jing, GUO Song, HE Ling-yan, HUANG Xiao-feng
In order to identify the characteristics of the particle effective density in Shenzhen and the influencing factors, we used a centrifugal particle mass analyzer (CPMA) combined with a differential mobility analyzer (DMA) to simultaneously measure the size-resolved effective density of particles of 50to 500nm at an urban site from September 2020 to February 2021. The median effective density ranged from 1.29 to 1.53g/cm3, increasing with the particle diameter, and the effective density in autumn was slightly lower than that in winter. During the clean period, the effective density of particles was low and a bimodal distribution was observed. The median effective density of a low-density mode was in the range of 0.70~0.80g/cm3, indicating the presence of fresh soot particles. While the median effective density of a high-density mode was in the range of 1.3~1.5g/cm3, which was between the material densities of secondary inorganic particles and organic particles, indicating mixing of them. During the polluted period, the effective density at different particle sizes increased and showed a unimodal distribution, which was a result of internal mixing. In the event of new particle formation, nitrate condensation was found to be the main reason for the subsequent increase in particle size and effective density.
2022 Vol. 42 (4): 1526-1533 [Abstract] ( 284 ) [HTML 1KB] [ PDF 626KB] ( 2137 )
1534 Numerical simulation of pollutant dispersion induced by vehicle moving in a T-shaped intersection
SU Chang-rong, MING Ting-zhen, WU Yong-jia, SHI Tian-hao, HE Fang-yan
In order to explore the influence of the moving vehicle on the air flow and pollutant dispersion at the T-shaped street intersection, a mathematical model coupling the fluid and pollutant concentration fields with the moving vehicle is established. The characteristics of the traffic-induced turbulence and pollutant diffusion in the T-shaped street intersection are revealed using the method of computational fluid dynamics. Based on filed synergy theory, the impact of the vehicle moving speed on pollutant dispersion is quantitatively evaluated. The results show that the turbulent kinetic energy induced by the moving vehicle increases with the increase of the vehicle speed. When the vehicle speed is 9m/s, the maximum turbulent kinetic energy on the central axis of the vehicle is 5times higher than that when the vehicle speed is 3m/s. However, the affected region of the turbulent kinetic energy in the rear of the vehicle is about 4m for all the cases. When the vehicle speed increases from 3m/s to 9m/s, the field synergy increases by 66%, and the average concentration of pollutants in the pedestrian area decreases by 43% With the increase of vehicle moving speed, the flow field at T-shaped street intersection is changed, and the synergistic effect between the velocity field and the pollutant concentration field is enhanced, which in turn reduces the pollutant concentration by improving the convective mass transfer effect in the pedestrian region.
2022 Vol. 42 (4): 1534-1544 [Abstract] ( 191 ) [HTML 1KB] [ PDF 1350KB] ( 674 )
1545 Environmental impacts of gasoline and oxygenated fuels when used on light-duty vehicles
ZHANG Meng-zhu, HAO Chun-xiao, GE Yun-shan, WANG Xin
Based on the WLTC test results of seven China-6 compliant light-duty vehicles, the global warming potential (GWP), ozone formation potential (OFP), and non-methane organic gases (NMOG) with gasoline, E10, and MTBE10 were calculated and discussed. The GWP of crew-averaged N2O and CH4 emissions were respectively 0.6 and 0.07g CO2e/km. The GWP of non-CO2 greenhouse gases with E10 and MTBE10 fuelling was higher than those of gasoline. Bio-E10 is capable of removing 5%~15% of life-cycle GWP from gasoline vehicles. E10 and MTBE10 both tended to increase benzene hydrocarbon (BHC) emissions and therefore OFP. The NMOG from the test vehicles was roughly 30mg/km. The employment of oxygenated fuels, such as E10 and MTBE10, didn’t result in an obvious increase in NMOG.
2022 Vol. 42 (4): 1545-1551 [Abstract] ( 246 ) [HTML 1KB] [ PDF 465KB] ( 1543 )
1552 Effects of land and sea breeze on pollutant diffusion in northern Shanghai
XIAO Ben, JIA Hong-wei, XU Jia-jia, KANG Yan-ming, ZHONG Ke
The north side of Shanghai has complex sea and land terrain and is a heavily polluted area. Numerical simulation method is employed to study the influences of sea and land breeze on pollutant diffusion in this area, including the zones of Shanghai suburb-Chongming Island-Qidong and the north branch channel and the south branch channel between the three areas. The equivalent method is adopted to characterize the near ground air heat change caused by solar radiation and long wave radiation. The simulations are in good agreement with ECMWF reanalysis data. The results show that the sea breeze forms in both the wide sea (South Branch waterway) and the narrow sea (North Branch waterway) regions during the sea breeze period, and the former one occurs about one hour earlier than the latter. During the land breeze period, only the two sides of the wide sea have obvious land breeze, among which land winds from Shanghai can cross the wide sea region to Chongming. The effect of the sea breeze on the diffusion and dilution of air pollutants depends on the temporal and spatial relationship between the sea breeze front and the pollutants. When the pollutants are discharged and accumulated before the sea breeze front, they will be drawn into the reflux zone by the front to the high altitude, and the sea breeze blows with a cleaning effect. Conversely, when the pollutants are emitted and dispersed behind the sea breeze front, the sea breeze will push the pollutants into the inland area and cause a lasting pollution process. The land wind blows the pollutants discharged at midnight away from the Shanghai land area, but the pollutants will enter the Chongming area with the land wind, and deteriorate the local air quality. The pollutants emitted in the early morning will only be blown to the offshore area by the land wind, and will pollute the land area again with the subsequent sea wind.
2022 Vol. 42 (4): 1552-1561 [Abstract] ( 363 ) [HTML 1KB] [ PDF 1651KB] ( 1418 )
1562 The spatiotemporal variation of surface ozone and the main driving factors in North China
KE Bi-qin, HE Chao, YANG Lu, YE Zhi-xiang, YI Jia-hui, TIAN Ya, MU Hang, TU Pei-yue, HAN Chao-ran, HONG Song
We used trend analysis (TA), geographically temporally weighted regression (GTWR) model and multi-factor generalized additive model (MGAM) to investigate the spatiotemporal variation and complex nonlinear relationships between O3 concentration and the factors influencing O3 concentration in North China from 2015 to 2020. The six annual average O3 concentration in North China was greater than 70μg/m3, with an overall trend of continuous growth and an increased rate of 2.3μg/(m3·a) on average (P<0.01); the annual O3 concentration of North China was the highest in summer (136.6μg/m3), followed by spring (112.4μg/m3), autumn (78.8μg/m3) and winter (56.5μg/m3); the spatial variation was high in the southwest and low in the northeast. Air temperature was the primary meteorological driver of O3 concentration in North China, followed by wind speed and precipitation; O3 concentration had a significant positive correlation with air temperature and wind speed, and a significant negative correlation with air pressure, relative humidity, precipitation, and visibility; the interaction of temperature and relative humidity, temperature and visibility, and temperature and barometric pressure was significant. The share of secondary industry in GDP was the primarily socio-economic driver factor of O3 concentration increase in North China, and the influence of industrial production electricity consumption and industrial SO2 emissions on the change of O3 concentration played an roles, too.
2022 Vol. 42 (4): 1562-1574 [Abstract] ( 387 ) [HTML 1KB] [ PDF 2199KB] ( 2510 )
1575 Effects of atmospheric diffusion conditions on vertical distribution of pollutants in Tianjin
LIU Jing-le, SHI Jing, YAO Qing, CAI Zi-ying, HAN Su-qin, JIANG Ming, CUI Ye
Using the air pollutant monitoring data and meteorological observation data in summer and winter during 2017~2019 in Tianjin, the effects of atmospheric vertical diffusion conditions on PM2.5 and O3 were studied based on the vertical observation of Tianjin Meteorological Tower. The results showed that the mass concentration of near-surface PM2.5 decreased with height, while the concentration of O3 increased with height. Influenced by the seasonal and diurnal variation of atmospheric turbulence intensity, there was a significant correlation between the PM2.5 mass concentration on the ground and at 120m height, but insignificant correlation between the PM2.5 mass concentration on the ground and at 200m height in winter. In summer, the correlation coefficient of PM2.5 mass concentration at 120m and 200m height was 0.72 and the PM2.5 mass concentration at 120m and 200m height were even higher than the ground in the afternoon. In summer, the difference of O3 mass concentration at different heights is lower than that in winter, and the O3 mass concentration were close to the ground at 120m height. Atmospheric stability, temperature inversion intensity, and temperature decline rate were taken as atmospheric vertical diffusion indexes, which had certain indicator effects on the vertical gradient of PM2.5 and O3. The correlation coefficient between TKE and PM2.5 mass concentration was -0.65 in winter, and that between TKE and ΔPM2.5 in summer was -0.39. The correlation coefficients between TKE and O3 concentration were 0.46 and 0.53, in summer and winter respectively. The correlation coefficients between TKE and ΔO3 concentration were 0.73 and 0.70, in summer and winter respectively. The weak downdraft has an obvious influence on the increase of O3 concentration. The correlation coefficients between the vertical velocity at 40m height and O3 concentration were -0.54 and -0.61 in winter and summer, respectively. Through the analysis of a typical PM2.5 heavy pollution process and typical O3 pollution processes, it is found that the changes of atmospheric stability, temperature decline rate and TKE were closely related to the generation, extinction, maintenance and variation of PM2.5 pollutants. The formation of O3 pollution near the surface was closely related to favorable photochemical reactions. In addition, the transport influence of downdraft should also be paid attention to during O3 pollution processes.
2022 Vol. 42 (4): 1575-1584 [Abstract] ( 329 ) [HTML 1KB] [ PDF 739KB] ( 1425 )
1585 Spatiotemporal patterns and driving forces of NO2 concentrations from different emission sources in the energy golden triangle of China
SHEN Yong-lin, LUO Ji-hao, Ma Yu-yang, YAO Ling, HU Chu-li
In order to understand the air pollution caused by the utilization of EGT resources and development, the air monitoring data were derived from OMI (ozone monitoring instrument) sensor, combined with data of industrial structure, vehicle ownership, national policies and measures, etc. The spatial and temporal characteristics of tropospheric NO2 vertical column concentration in the EGT region from 2005 to 2019 were extracted by using the emission source analysis method of urban and rural NO2 concentration differences, and the driving factors affecting the regional atmospheric NO2 concentration were analyzed and discussed. Finally, comparing the spatial characteristics of TROPOMI (tropospheric monitoring instrument) with OMI NO2 products, the results show that The correlation coefficient between NO2 concentration of EGT coal chemical source and output value growth of the secondary industry was 0.71 (P<0.05), indicating that the NO2 concentration of long-term urban source and coal chemical source extracted by this method can effectively reflect the adjustment of regional industrial structure and changes in national policies and measures. The NO2 concentration increased from 90.56molec/m2 in 2005~2011 to 720.77molec/m2 in 2012~2015, and then decreased to 247.36molec/m2 in 2016~2019. The spatial-temporal variations of NO2 illustrate that the economic development model in the EGT has gradually evolved from a small-scale and moderate-polluting scattered model to a large-scale, heavy-polluting extensive model, and then to a large-scale, light-polluting fine model. Compared with the Beijing-Tianjin-Hebei Urban Agglomeration, the Central of China, and the Yangtze River Delta region, the changing characteristics of the contribution of traffic and industrial emissions to urban source NO2 pollution in the EGT further reflect the development of urbanization and the optimization of industrial structure. In comparison with OMI, it can be found that TROPOMI provides rich and detailed image information in a short time series, and as the observation time increases, it can provide long time series and precise atmospheric NO2 pollution monitoring.
2022 Vol. 42 (4): 1585-1593 [Abstract] ( 333 ) [HTML 1KB] [ PDF 1536KB] ( 1052 )
1594 Impacts of ultrasonic humification on size-distribution and concentration variations of indoor bioaerosol and its optimization strategy
CHEN Lu-an, YANG Chuan-jun, GU Yu-qian, LIU Xue-hu, YANG Zi-li
This work experimentally investigated the size-distribution and concentration changes of indoor bioaerosol before and after ultrasonic humidification via the orthogonal experiment methods in three heated experimental chambers (23℃) to clarify the exposure risk of indoor airborne bacteria and fungi during ultrasonic humidification. Effectiveness of three well-recognized influencing factors, i.e., target relative humidity (RH=40%, 55%, 70%), humidifier water type (distilled water, tap water, cooled boiled water), and window opening degree (0, 1/6, 1/3) on mitigating the exposure risks was also rated according to Range Analysis and Analytical Hierarchy Process (AHP). The results showed a substantial increase of indoor bacterial and fungal aerosol concentrations, by 294% and 798%, respectively, after ultrasonic humidification; the surged microbes were concentrated in the inhalable ranges. The three factors varied in their effectiveness in mitigating the bioaerosol exposure during humidification, which was ranked by AHP as: humidifier water quality (45%)> target relative humidity (44%)>window opening (11%). To minimize the exposure risks, distilled water and a medium humidification level (such as RH=55%) should be prioritized for ultrasonic humidification, while the effect of window opening degrees is relatively insensitive.
2022 Vol. 42 (4): 1594-1600 [Abstract] ( 282 ) [HTML 1KB] [ PDF 1038KB] ( 1494 )
1601 Synthesis of Mn1-yNiyOx catalyst and its high efficient performance for toluene catalytic combustion
ZHOU Yuan-yuan, LIU Han, DENG Lin, WU Gong-de, WAN Jie, WANG Xiao-li, HU Chun-zheng, YU Xian-kun, YANG Xiao-jun
Series of dual meta oxides Mn1-yNiyOx (y=0.1~0.5) catalysts were prepared by hydrothermal co-precipitation to investigate the effect of nickel doping on manganese-based oxides for toluene catalytic combustion reaction. Manganese to nickel ratio was optimized and the corresponding thermal stability as well as durability performances were also evaluated. The physical structure and redox performance of the obtained catalysts were characterized through XRD, N2 adsorption/desorption, SEM, H2-TPR and XPS. Results revealed that strong interaction exists between Mn and Ni, which results in the generation of more high valent Mn4+ and surface adsorbed oxygen species, thus providing more reactive sites and enhancing the catalytic oxidation performance. Mn0.8Ni0.2Ox proposed the best toluene removal efficiency in the catalytic combustion, as well as excellent thermal stability and durability. Compared with MnOx, its T50 and T90 were reduced by 12 and 11℃, respectively, demonstrating complete toluene elimination at 238℃, and the carbon balance was about 99% without secondary pollution. This work provides promising materials with practical potentials for the catalytic combustion of volatile organic compounds (VOCs) as well as new insights regarding catalyst design principles.
2022 Vol. 42 (4): 1601-1609 [Abstract] ( 171 ) [HTML 1KB] [ PDF 1184KB] ( 1014 )
Water Pollution Control
1610 The abundance and contamination characteristics of micro/nano-plastics in drinking water distribution systems
ZHENG Ying-ying, ZHANG Ke-jia, CEN Cheng, MAO Ru-yin, ZHANG Tu-qiao
Micro/nano-plastics are becoming a research hotspot due to the characteristics of wide distribution, small particle size, difficulty in degradation, and can adsorb toxic substances, etc. However, the information on the status of environmental contamination and removal is rare. In this review, the research status of micro/nano-plastics in drinking water distribution systems (DWDS) was discussed, which was from the perspectives of the sources, migration characteristics and safety hazards of water quality. The results showed that residual micro/nano-plastics can be carried into DWDS by the effluent of water treatment plants. Besides, pipe material, flow velocity, mechanical wear and residual chlorine may affect the release of micro/nano-plastics. The spatial and temporal variation of micro/nano-plastics was affected by the inherent characteristics (e.g., density and charge) in DWDS. In the process of drinking water transmission and distribution, the water quality and safety of the DWDS has been considered that is relevant to the reaction between micro/nano-plastics with organics, microorganisms and other substances. Therefore, the review makes a prospect for the future research direction, in order to provide theory basis for further understanding of the impact of micro/nano-plastics on the drinking water safety, in addition to the control of micro/nano-plastics.
2022 Vol. 42 (4): 1610-1617 [Abstract] ( 361 ) [HTML 1KB] [ PDF 441KB] ( 1306 )
1618 Anti-fouling mechanism for ultrafiltration membrane of modified surface by carbon nanotubes
WANG Die, WANG Xiao-yang, CHEN Xi, HAN Min-yuan, WANG Yu-ting, XIANG Wen-yu, YAO Jing-mei, HAN Le
Carbon nanotubes (CNTs) as the core modification material was spray-coated on polyether sulfone (PES) ultrafiltration membrane towards enhanced anti-fouling property. The permeability of the modified membrane decreased slightly and the hydrophilicity increased obviously, and the layer of woven CNT fibre also increased the membrane roughness. In the presence of bovine serum albumin (BSA) of 20mg/L, the CNT-10membrane exhibited a high flux recovery rate up to 95.7% with the reversible fouling ratio nearly 60%. Then, applying electrical impedance spectroscopy (EIS) to measure membrane fouling extents provided the membrane real- imaginary impedance, conductance and capacitance. The Nyquist curve of CNT-10exhibited less horizontal shift (real impedance increases) towards the right side, and the radius of the curve was not significantly expanded after contamination test, in consistent with the slightly decreased conductance and relatively stable capacitance. It was concluded that the modified membrane has less foulant adhesion, agreeing with the flux variation. The discussion on frequency division of frequency-conductance diagram showed that BSA contaminated the entire surface and membrane of PES-V, but did not pollute the entire surface and membrane of CNT-10. The free energy analysis of the interfacial interaction between CNT modified layer and BSA was only half that for the control, indicating small membrane-foulant attraction, which explained the excellent anti-fouling performance of the CNT modified membrane by thermodynamics.
2022 Vol. 42 (4): 1618-1624 [Abstract] ( 266 ) [HTML 1KB] [ PDF 1075KB] ( 967 )
1625 Apparent and microscopic performance of low temperature and low dissolved oxygen EBPR system subjected to side-stream phosphorus recovery
TIAN Wen-qing, YU Xiao-jun, DENG Ying, CAI Yu-qi, JIN Hai-dong, KANG Su-qin, MA Juan
Two alternative anaerobic/oxic SBR (A/O-SBR) reactors controlled at medium temperature (22±1)℃SBR1and low temperature (14±1)℃SBR2were operated to investigate the effect of side-stream phosphorus recovery on nutrients removal performance, microbial community structure and phosphorus recovery potential of mainstream EBPR systems under low dissolved oxygen (DO = 1mg/L). The results showed that the nitrogen and COD removal performance of SBR1and SBR2 were not influenced by the introduction of side-stream phosphorus recovery. In terms of phosphorus removal, however, EBPR performance of SBR1was more stable and more tolerant to phosphorus deprivation. During the phase of side-stream phosphorus recovery, the average efficiency of phosphorus removal in SBR1reached 90.7%, while SBR2 was 78.4%. It was also found that microaerobic EBPR subjected to side-stream phosphorus recovery could maintain a relatively stable volatile suspended solids (VSS) concentration at low temperature. While the value of SVI increased from 104.6mL/g to 216.8mL/g after side-stream phosphorus recovery, resulting in sludge bulking in SBR2 system. The result of high-throughput sequencing based on 16S rRNA showed that the microbial community structure of the mainstream system changed significantly after side-stream phosphorus recovery. The relative abundances of Candidatus Competibacter, Flavobacterium and Dechloromonas rapidly increased and Candidatus Accumulibacter fell from 12.5% to 6.4%. It was estimated that the average phosphorus recovery potential of SBR1 and SBR2 were 68.8% and 69.4%, respectively, with the side-stream ratio of 1/3. In a conclusion, the temperature was one of the important factors to ensure the stable operation of side-stream phosphorus recovery in an EBPR system under low DO.
2022 Vol. 42 (4): 1625-1634 [Abstract] ( 222 ) [HTML 1KB] [ PDF 797KB] ( 1135 )
1635 Nitrogen removal characteristic of A2O system with natural corncob supplemented into anoxic zone as carbon source
SHEN Qiu-shi, JI Fang-ying, WEI Jia-Zhi, JIANG Lei, ZHANG Qian, MAO Yuan-xiang, LIU Cao-cong
Given that low carbon source sewage has advantage of nitrification rather than denitrification, natural carbon source corncob was added into anoxic zone of a pilot A2O to explore the denitrification potency and characteristics, by means of mass balance, denitrification rate and microbial community analysis. The results showed that TN removal efficiency increased by 13%, and effluent TN decreased from 16.2 to 10.0mg/L. Meanwhile, there was no exceeding risk of ammonia nitrogen and chroma in effluent. Mass balance demonstrated that the consumption amount of oxidation and effluent residual of COD both decreased, while its utilization rates for denitrification and sludge proliferation increased, which stimulated nitrogen removal amount. Therein, nitrogen removal was mainly contributed by denitrification. An integrated denitrification system was established in this reactor: the denitrification rates of newly formed biofilm and suspended sludge were 24.89 and 32.42mg/(L×h) separately in the presence of influent carbon source, which achieved this system with rapid denitrification; while influent carbon source was depleted, the denitrification rates were 4.71 and 1.73mg/(L×h) respectively, and their denitrification rates per biomass amount were 1.58 and 59.1mg NO3--N/(g VSS×h) accordingly, which indicated that corncob was primarily used by biofilm for maintaining denitrification process. The most dominant denitrifier in this system was Azospira. Morover, denitrifiers like Iamia and Haliangium, capable of adhering to growth, enriched on the biofilm, and Sulfuritalea, which could degrade corncob’s lignin, assembled on the biofilm as well.
2022 Vol. 42 (4): 1635-1642 [Abstract] ( 268 ) [HTML 1KB] [ PDF 942KB] ( 747 )
1643 Analysis of coagulant hydrolysed species in the electro-hybrid ozonation-coagulation process—Based on monopolar/bipolar electrode arrangement
JIN Xin, LIU Meng-wen, XIE Xin-yue, WEI Yi-xiong, SONG Ji-na, JIN Peng-kang, WANG Xiao-chang
In this paper, the hydrolysed coagulant species in the electro-hybrid ozonation-coagulation process (E-HOC) were analysed at different initial pH and different electrode arrangement conditions, and the removal efficacy was investigated. The results showed that a higher organic matter removal efficiency was exhibited at initial pH 5in the E-HOC process. Compared with the E-HOC process with monopolar connections, the organic matter removal efficiency of the bipolar arrangement is improved by 12.29%, energy consumption is reduced by 1.74kWh/g, and Faradaic efficiency is improved by 2.37%. Ferron analysis and electrospray ionization mass spectrometry (ESI-MS) were used to analyze the hydrolysed Al species of the system. In the E-HOC process, weak acid conditions (initial pH 5) and bipolar arrangement can lead to the enhanced polymeric species generation, which improved both the coagulation and catalytic ozonation ability in the E-HOC system.
2022 Vol. 42 (4): 1643-1651 [Abstract] ( 219 ) [HTML 1KB] [ PDF 689KB] ( 1193 )
1652 Adsorption-Photocatalysis for the Removal of NDPhA by Fe/Ti-Mil-NH2
XIE Ya-wei, HUANG Jing-jie, JIANG Yi-heng, LIU Hong-yuan
A composite adsorption-photocatalyst, Fe/Ti-MIL-NH2, was synthesized via the hydrothermal method and utilized to degrade NDPhA. The Fe/Ti-MIL-NH2 with Fe-Ti molar ratio of 3:1 could degrade more than 84.4% of NDPhA under various conditions, and 95.1% under adding 10 mmol/L HCO3-. Compared to Fe-MIL-NH2, the excellent performance of Fe/Ti-MIL-NH2 (3:1) was attributed to the in situ formation of intimate heterojunctions, which increased the specific surface area (310.2m2/g), accelerated the separation of photogenerated cavity pairs, and inhibited their complexation. Both surface adsorption and distribution existed during the adsorption of NDPhA on Fe/Ti-MIL-NH2 as observed from kinetic and adsorption isotherm fitting. The combination of radicals (·O2-, ·OH) and non-radical (h+, Fe[IV]=O) in the Fe/Ti-MIL-NH2 photolytic system was responsible for NDPhA degradation. Diphenylamine and 2-Nitrodiphenylamine and/or 4-nitrodiphenylamine were identified as the main intermediates during NDPhA degradation, and the pathways were speculated based on these intermediates. In addition, Fe/Ti-MIL-NH2(3:1) could completely remove NDPhA at concentrations <0.1mg/L in source water of water treatment plant and maintain an NDPhA removal efficiency of 83% after 5times of use, indicating the high stability of this material.
2022 Vol. 42 (4): 1652-1662 [Abstract] ( 263 ) [HTML 1KB] [ PDF 1317KB] ( 3945 )
1663 The effects of effluent reflux on characteristics and microbial community of anammox granular sludge
FU Hui-min, LENG Ji-xuan, WENG Xun, YAN Peng, CHEN You-peng
From the perspectives of mass transfer, anammox activity and stability, this study evaluated the effect of effluent reflux on the structure and function of Anammox granular sludge (AnGS) in EGSB reactor with or without reflux. The results showed that increased reflux provided better flow conditions, which enabled the substrate to better contact with granular sludge. When nitrogen load rate ranged from (3.16to 3.79) kg/N·(m3·d), the original removal rates of nitrite (60%) and ammonia nitrogen (65%) were increased to more than 95% and the specific anammox activity increased by 31.54%. With the increased gas production and granular activity by reflux, the internal pressure of bubbles in AnGS was increased due to the limited pore volume. The microstructure of AnGS was changed and the porosity of AnGS was increased from 41.3% to 59.4%. In addition, the higher shear force and better mass transfer effect caused by effluent reflux greatly improved the stability of AnGS. The effluent reflux maintained and enriched candidatus-Jettenia in the seed AnGS, and enabled some bacteria maintaining the stability of the AnGS and improving viability. The internal porous structure and efficient nitrogen removal of the AnGS (such as Simplicispira) leads to better stability (such as Rheinheimera), which is conducive to the stable operation of AnGS in practical engineering applications.
2022 Vol. 42 (4): 1663-1671 [Abstract] ( 199 ) [HTML 1KB] [ PDF 937KB] ( 1060 )
1672 Magnetic graphite oxide as efficient catalyst for electrochemical treatment of printing and dyeing wastewater
FU Ming-hao, LU Jun, CHENG Quan-yuan, LIU Xiao-chen, ZHENG Hua
Magnetic graphite oxide (MGO) catalyst was synthesized using potassium ferrate as iron precursor and oxidizing graphite oxide mineral. It was used to fabric cathode (MGO/CB) by adding carbon black (CB) on a carbon fibre cloth substrate, which can reduce dissolved oxygen to produce reactive oxygen species (ROS) for the treatment of simulated wastewater containing reactive red X-3B dye. The morphology and electrochemical properties of MGO were measured by scan electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical working station. The surface of the lamellar MGO possessed iron oxide nanoparticles with different crystal structures. These active species showed synergistic effect in electrocatalysis. The crystal phase and catalytic activity of ferric oxide were influenced by calcination temperature. At 300oC of calcination, MGO/CB cathode exhibited high electrochemical treatment efficiency for reactive red X-3B degradation. It was found that 1O2 and ·O2- were dominant ROS. The decolorization reached 100% and CODcr removal reached 77.1% in 4h of electrolysis. Magnetic graphite oxide was stable and can be reused in successive cycles.
2022 Vol. 42 (4): 1672-1680 [Abstract] ( 729 ) [HTML 1KB] [ PDF 1847KB] ( 1201 )
1681 Phosphorous recovery from wastewater with low phosphorous concentration by means of HAP-seeded crystallization of calcium phosphate
XIAO Hui-yi, NIE Xiao-bao, WAN Jun-li, DENG Quan-qing, WANG Yi-rui, LONG Yuan-nan, JIANG Chang-bo
Phosphorous recovery from secondary treated effluent by crystallization of calcium phosphate (Ca-P), is one of effective strategies for phosphorous recovery from municipal wastewater. However, this strategy still needs further improvement, such as enhancing the quality of final products and improving the adaptability to low PO4-P concentration. In this paper, phosphorous in simulated secondary treated effluent with initial PO4-P concentration of 1.0mg/L was recovered by Ca-P crystallization using hydroxyapatite (HAP) as seeds. The recovery effects of induced crystallization were compared to that of homogeneous one, and the influence of both Ca/P mole ratio and dosage of seeds were investigated. Moreover, the induced crystal mechanism of Ca-P under low PO4-P concentration was studied based on phosphorous recovery effects and SEM, EDS, XRD and FTIR of crystal products. The results showed that the disturb of seed materials to the quality and purity of final products was minimized, since HAP was the major polymorph of final products. For simulated secondary treated effluent, HAP-induced Ca-P crystallization possessed high phosphorous recovery performance and rapid start-up. The induced crystal models of Ca-P crystallization included layer-by-layer crystallization on the surface of seeds, and crystal bridge model of which crystallization occurred within the space among seeds particles. Under experimental conditions, phosphorous recovery efficiency over 80% was obtained, with HAP and its precursors, ACP and OCP, the main polymorphs of final products. CaCO3 crystallization was proved to take place simultaneously with Ca-P, which disturbs the recovery of phosphorous. The result provides new ideas for simultaneous improvement of recovery efficiency and the quality and purity of final products for low concentrated PO4-P wastewater.
2022 Vol. 42 (4): 1681-1687 [Abstract] ( 225 ) [HTML 1KB] [ PDF 825KB] ( 1402 )
1688 Effect of iron scraps on anammox systems at low temperature
LI Tian-hao, XU Yun-xiang, GUQ Zhi-han, HUANG Zi-chuan, LIU Wen-ru, SHEN Yao-liang
The effects of iron scraps addition and its dosing methods on the nitrogen removal performance and microbial community of anaerobic ammonia oxidation(anammox)reactors were investigated at low temperature (<20℃). The results showed that when the dosage of iron scraps was 10g/L, both the direct (R2) and indirect (R3) dosing methods caused short-term inhibition of anammox bacteria. Consequently, the total nitrogen removal effieiency reduced by 4.7% and 3.4%, respectively. The total nitrogen removal effieiency of the control group (R1), R2 and R3 all reached to about 70% after 30 days of continuous operation. During the stable operation,Rs(the ratio of NO2--N removal to NH4+-N removal) and Rp(the ratio of NO3--N generation to NH4+-N removal) of R2 were 1.57 and 0.22, Rs and Rp of R3 were 1.49 and 0.23, which were closer to the theoretical value of anammox than R2. The decrease of DO concentration and the increase of pH was observed likely due to the corrosion of iron scraps in the water. The iron concentration of sludge in R2 and R3 was 1.64 times and 1.93 times higher than that of in control reactor. These results suggested that the iron scraps addition not only improved the living habitats, but also supplyed iron for anammox bacteria. High-throughput sequencing results showed that during the 20~50days operation, the relative abundance of the dominant anammox bacteria Candidatus_Kuenenia in R1, R2, and R3 increased by -1.05%, 0.14%, and 0.96%, respectively. This indicated that the addition of iron scraps promoted the growth of anammox bacteria at low temperature, while the enhancment was more obvious with the indirect addition of iron scraps.
2022 Vol. 42 (4): 1688-1695 [Abstract] ( 237 ) [HTML 1KB] [ PDF 1005KB] ( 898 )
1696 The stability mechanism of algal-bacterial granular sludge
LIU Yi, ZHANG Bing, SHI Wen-Xin, ZHU Yi-chun, LIU Zu-wen
A stable algal-bacterial granular sludge (ABGS) system was established rapidly within 18 days by inoculating with aerobic granules and targeted algae (Chlorella and Scenedesmus) under non-aeration conditions. The results indicated that ABGS had higher biological activity, better nutrients removal performance, and higher mechanical strength than the conventional AGS, indicating the superior stability of ABGS. Moreover, the content of protein (PN) in extracellular polymeric substances (EPS), especially tightly bound layer EPS (TB-EPS), was found increasing significantly during the granulation. Specifically, the PN content of 114.4mg/g MLSS at the end of the operation was about 2.8 times higher than that of AGS. Further analysis of EPS components by three-dimensional fluorescence spectroscopy showed that amino acids, tryptophan, aromatic proteins, complex amino acids and tryptophan-like substances in TB-EPS were conducive to maintain the structural stability of granular sludge. In terms of microbial community structure, the ABGS had a higher microbial diversity and community richness than AGS. The enrichment of the prokaryotic Chloroflexi and Planctomycetes, and the eukaryotic Chlorophyta was beneficial to enhance the stability of the system.
2022 Vol. 42 (4): 1696-1705 [Abstract] ( 454 ) [HTML 1KB] [ PDF 3275KB] ( 1249 )
1706 Enhanced denitrifying phosphorus removal in novel multistage anoxic-oxic process
LU Rei-peng, XU Wen-jiang, LI An-feng, Dong Na
Based on the multistage anoxic-oxic (MAO) process and the theory of denitrifying phosphorus removal, a noval MAO process (DPR-MAO) with ability of denitrifying phosphorus removal was designed. In this study, the nitrogen and phosphorus removal performance and the microbial community characteristics of each reaction tank were investigated. During period of stable operation, the average COD, TN, NH4+-N and TP concentration in effluent were 7.07, 9.04, 0.34 and 0.49mg/L, respectively. Meanwhile, the average removal efficiecny of COD, TN, NH4+-N and TP were 98%, 87%, 99% and 93%, respectively. The effluent quality of DPR-MAO process could meet the first A level of the "Discharge standard of pollutants for municipal wastewater treatment plant” (GB 18918~2002). High-throughput sequencing results suggested that Proteobacteria, Bacteroidetes and Chloroflexi were the dominant phyla in each reaction tank, accounting for 61.85% ~ 75.58%、16.39% ~ 22.60% and 1.52% ~ 4.76% of the total phyla, respectively. Further analysis at the genus level found that Thiothrix, Comamonas, Candidatus Accumulibacter and Pseudomonas were the dominant genus for denitrifying phosphorus removal. The DPR-MAO process realized the enrichment of denitrifying phosphorus accumulating organisms and the efficient removal of nitrogen and phosphorus from wastewater.
2022 Vol. 42 (4): 1706-1713 [Abstract] ( 308 ) [HTML 1KB] [ PDF 554KB] ( 9136 )
1714 One step preparation of biomass based magnetic porous carbon and efficient adsorption of CBZ
CHEN Ai-xia, Tian Zheng, WEI Xiao, Hu Rui-rui, Zhang Yi-xuan, Guan Juan-juan
In order to utilize waste agricultural and forestry biomass as resources and effectively remove carbamazepine (CBZ) from water. Inspired by the “leavening” strategy, poplar sawdust was transformed into magnetic porous carbon (MPC) with developed pore structure by using KHCO3 as activator and FeCl3·6H2O as magnetic precursor. The optimum product MPC-2-0.3 was prepared by adjusting the ratio of raw materials. Its specific surface area was 1002.48m2/g and the CBZ adsorption capacity of 50mg/L was 202.70mg/g. SEM and XRD showed that Fe nanoparticles were successfully doped into porous carbon, giving porous carbon excellent magnetic separation ability. The kinetics and isotherms of the adsorption process were more in line with the pseudo second-order kinetics and Langmuir model. It was clarified that the main adsorption mechanisms were adsorption sites, π-π interaction and hydrogen bonding. MPC-2-0.3 had excellent adsorption performance at room temperature and a wide pH range, and it was easy to separate and regenerate.
2022 Vol. 42 (4): 1714-1725 [Abstract] ( 259 ) [HTML 1KB] [ PDF 1199KB] ( 895 )
1726 Research advances on continuous flow aerobic granular sludge cultivation
FU Xiang-yun, YU Cheng, WANG Kai-jun, MA Jin-yuan, LIU Min
Aerobic granular sludge (AGS) has attracted much attention for its excellent settleability, high biomass concentration and outstanding performance in resisting shock loading. Compared with traditional sequencing batch reactor (SBR), continuous flow reactor (CFR) has the advantages of easy control, moreover, matching the scale and continuous flow mode of most actual sewage plants. Therefore, continuous flow aerobic granulation technology is more feasible for widespread and application. Through literature analysis and organization, the challenges of continuous flow AGS technology was summarized. In order to further promote the practical application of continuous flow AGS technology, this work provided the current advances on continuous flow AGS cultivation, combed the experiences and lessons and finally proposed the future research directions.
2022 Vol. 42 (4): 1726-1736 [Abstract] ( 425 ) [HTML 1KB] [ PDF 534KB] ( 3706 )
1737 A method on sewer inflow identification using fiber-optic distributed temperature sensing
YIN Hai-long, GUO Long-tian, HU Yi-yang, LÜ You
To overcome the shortcomings of physical inspection that needs prerequisite pipe draining and also can not afford real-time in-pipe monitoring, a sewer inflow detection method based on fiber-optic distributed temperature sensing (FDTS) was developed in this study, enabling non-disrupted timely monitoring of sewage and rainfall inflow into sewers. A temporal-spatial high-resolution monitoring (i.e., 1m interval in spatial scale and 1min interval in temporal scale) was performed using FDTS for the studied sewer reach, and over 118million in-pipe water temperature data was obtained. With interpreted in-pipe temporal-spatial water temperature mapping, a sewer inflow identification method based on the background noise of water temperature change at spatial and temporal scale was presented, and the determined spatial and temporal background noise levels at a condition free of external sewer inflow disruption were ±0.2℃ and ±0.5℃, respectively. By a denoising treatment method for water temperature mapping, the dry-weather sewage discharge and wet-weather rainfall inflow into sewers were identified automatically, which is in line with on-site investigated results. Therefore, the developed method is reliable for dynamic sewer inflow identification and location.
2022 Vol. 42 (4): 1737-1744 [Abstract] ( 275 ) [HTML 1KB] [ PDF 940KB] ( 1462 )
1745 Study on the fluorescence characteristics and DBPsFP based on EEMs and fraction of DOM—— a case of source water in a southern city
CAI Li-tong, LI Qing-song, MA Xiao-yan, LI Guo-xin, CHEN Guo-yuan, WANG Ji-ping, LAI Cheng-ran, LIANG Xin-rui
The characteristics of dissolved organic matter(DOM) and three-dimensional fluorescence spectroscopy(3D-EEMs) of each component of source water in South-China reservoir were analyzed by fluorescence regional integration(FRI) and Supelite DAX-8 Macroporous Resin. the relationship between disinfection by-products formation potential, water quality indicators and fluorescence intensity were also determinated. The proportion of hydrophobic substances in the reservoir was more than 70% of UV254. The fraction of HOB(hydrophobic bases) mainly contained tyrosine-like proteins and tryptophan-like proteins, while the fraction of HOA(hydrophobic acids) and HIS(hydrophilic substances) contained more fulvic acid. The trihalomethane formation potentials (THMsFP) of HOA, HOB, HON and HIS fractions were 151.5~194.1μg/L, 60.6~65μg/L, 123.4~189.9μg/L and 104.1~187.1μg/L, respectively, and the haloacetamide formation potential(HAcAmsFP) were 2.7~3.7μg/L, nd~0.1μg/L, 1.3~3.9μg/L and 2.2~8.4μg/L, respectively. The precursors of THMs(trihalomethane) and HAcAms(haloacetamide) were distributed uniformly in HOA, HON and HIS fractions. UV254(R2=0.93), HIX(R2=0.59) presented a good linear relationship with THMsFP, which can be used as an indicator for predicting THMsFP among fractions. UV260(R2=0.80) and DON(R2=0.74) showed a relatively good linear relationship with HAcAmsFP, which can be used as the parameters for predicting HAcAmsFP. Pearson correlation analysis manifested that the two humus-like regions(III,V) were significantly correlated with the formation potential of THMs, which meant that these substances were important precursors of THMs of source water in the reservoir. The formation potential of THMs and HAcAms can be predicted by the fluorescence regional integration among the fractions.
2022 Vol. 42 (4): 1745-1753 [Abstract] ( 270 ) [HTML 1KB] [ PDF 1487KB] ( 886 )
Solid Waste
1754 Study on flow field and working parameters of bioreactor for oily sludge degradation
LUO Fei, HE Li-le
In order to improve the degradation efficiency of oily sludge by bioreactor, the degradation process of oily sludge by pseudomonas aeruginosa NY3 in bioreactor were studied. The gas-liquid-solid three-phase flow field dynamics model and population balance model (PBM) in the bioreactor were established, and the bubble diameter distribution and stirring speed were simulated by FLUENT software. It was studied that the bubbles with a diameter of less than 6mm account for 85%, which can effectively increase the concentration of dissolved oxygen in the reaction system,and the optimal off-bottom suspension speed of the reactor was 150r/min. Secondly, the relationship model of aeration rate with time was established by using the principle of oxygen conservation, and the optimal bacterial uptake was determined to be 15.23% and the temperature was 32.56℃ through design experiments, which guided the selection of technological parameters in the final degradation process. Finally, the optimal working parameters were set, and 6kg oily sludge was degraded by multi-functional bioreactor. After 9 days of reaction, the degradation rate of petroleum hydrocarbon was up to 86.20%, and the oil content was 1.46%. The bioreactor degradation of oily sludge has the advantages of short cycle and high efficiency, and provides an effective and reliable new way for the treatment of oily sludge.
2022 Vol. 42 (4): 1754-1761 [Abstract] ( 216 ) [HTML 1KB] [ PDF 1334KB] ( 929 )
1762 Effects of pH on the production of volatile fatty acids from citrus waste and waste activated sludge by anaerobic co-fermentation
SUN Hong, XIAO Xiang-zhe, LUO Jin-cai, ZHANG Liang, LIN Peng, DONG Shan-yan, ZHU Yi-chun
In order to improve the production of volatile fatty acids (VFA), the effects of different ratios of volatile solids(VS) from citrus waste and waste activated sludge and regulating pH in fermentation processes were studied. The results showed that adjusting the pH of the co-fermentation system to 6could promote the accumulation of VFA. When the ratio of VS from citrus waste and waste activated sludge reached 2, the maximum VFA yield was 11183.12mg/L, which was 1.75times higher than that without pH control. Furthermore, the essential oil from citrus waste could inhibit the methanogenic process, which was strengthened by controlling pH in the fermentation process. After adding citrus waste, the microbial community structure of the co-fermentation system showed significant advantages. VFA related microbial population increased significantly while methanogenic bacteria consuming acetic acid decreased, which was conducive to the accumulation of VFA. The results of this experiment can provide a theoretical basis for optimizing the performance of VFA production by anaerobic co-fermentation of citrus waste and waste activated sludge.
2022 Vol. 42 (4): 1762-1769 [Abstract] ( 238 ) [HTML 1KB] [ PDF 588KB] ( 1089 )
1770 Regulation of acidified dry anaerobic digestion of kitchen waste and microbial community analysis
WANG Pan, YANG Xin-yu, ZHENG Yi, REN Lian-hai
Aiming at the problems caused by the accumulation of propionic acid and butyric acid during anaerobic digestion, the sludge with propionic acid and butyric acid tolerant microorganism were domesticated, and they were added into the acidified systems of dry anaerobic digestion of kitchen waste to explore the effects on methane production and microbial communities. After treated by the sludge with propionic acid and butyric acid tolerant bacteria, the propionic acid concentration reduced by 6900.81mg/L, and the cumulative methane production increased by 259%, while the butyric acid concentration reduced by 5371.56mg/L, and the cumulative methane production increased by 210%, respectively. The richness of bacteria in the acidified systems was significantly improved after the regulation with propionic acid and butyric acid tolerant bacteria. The analysis of microbial community structure at genus level showed that the relative abundance of Sporanaerobacter and Proteiniphilum, having the ability of degrading volatile fatty acids, began to increase in the reactors treated by the sludge with propionic acid tolerant bacteria. After adding the sludge with butyric acid tolerant bacteria, the relative abundance of Sporanaerobacter increased. Sporanaerobacter have a synergistic effect with acetic acid methanogens. According to the analysis of archaea, the relative abundance of hydro methanogens and acetic acid methanogens increased in the groups treated with propionic acid and butyric acid tolerant bacteria, respectively.
2022 Vol. 42 (4): 1770-1779 [Abstract] ( 333 ) [HTML 1KB] [ PDF 449KB] ( 1236 )
1780 Optimization of the first fermentation time based on biogas post-fermentation with rice straw
CHEN Guang-yin, CAO Hai-nan, HUANG Yan, WANG Yu, WANG Jing, CHANG Zhi-zhou, DONG Jin-zhu, WU Pei, FANG Cai-xia
To solve the problems of low chemical treatment efficiency and high treatment cost caused by entanglement of cellulose, hemicellulose and lignin in straw, the process of "first fermentation + NaOH treatment + secondary fermentation (PNS)" was adopted, and the effect of primary fermentation time on biogas production of straw was studied. The results indicated that the digested rice straw could still be used for biogas production with total solid (TS) biogas yield of 28.11-50.73mL/g TS, and the biogas yield was inversely proportional to first fermentation time. After the NaOH treatment, the material structure of digested rice straw was obviously damaged and a large amount of organic matter was leached out. The concentrations of COD, TN, NH4+-N and NO3--N in the rice straw leachate were significantly increased by 128.56%~213.62%, 93.92%~110.59%, 53.90%~73.78% and 112.08%~188.98%, respectively, compared with those without NaOH treatment. NaOH treatment did not destroy the skeletal structure of digested rice straw, but changed the relative content of functional groups of digested rice straw, which intensified the destruction of cellulose, hemicellulose and lignin. After first fermentation of 15, 25, 35d and NaOH-treatment, the digested rice straw were reused for biogas production. The TS biogas production of digested rice straw were increased by 77.37%, 119.41% and 159.94%, respectively, compared with that under control treatment. The longer primary fermentation time, the better effect of promoting biogas production. After the experiment, the total biogas yield of rice straw of the treatment of primary fermentation time with 15, 25 and 35d were 202.78, 205.15 and 210.21mL/g TS, respectively, which were significantly increased by 11.89%, 13.20% and 15.99% compared with that of correspending control, and the total fermentation time were extended by -12, -2 and 8days. In summary, when adopting the process of PNS, the primary fermentation time of 15d is suitable.
2022 Vol. 42 (4): 1780-1787 [Abstract] ( 182 ) [HTML 1KB] [ PDF 646KB] ( 597 )
Soil Pollution Control
1788 Remediation of Cd-Pb contaminated soil by coupled soil washing and electrochemical reduction
GAO Song, TONG Xin-yuan, WANG Yun, WANG Zhuo-qun, SUN Rui-lian
This study proposed a combination technique to explore whether the coupling of chelating agent washing and electrochemical reduction can improve the heavy metal removal efficiency. The removal performance, mass transport mechanisms and economic benefits were investigated based on both a coupling strategy and separate soil washing. The combination technique could effectively improve the removal efficiency of heavy metals, and the synergistic enhancement effect was related to the chelating ability and regeneration ability of the chelating agent. The aminopolycarboxylic acids could increased the removal efficiency of Cd and Pb by 15.24% and 27.05%, respectively. The low-molecular-weight organic acids increased the removal efficiency of Cd and Pb by 5.31% and 10.24%, respectively. Aminopolycarboxylic acids were more suitable for the combination system. The most cost-effective treatment in 48h was coupled EDTA washing and electrochemical reduction, where 46.60% of Cd and 76.93% of Pb were removed from the soil.
2022 Vol. 42 (4): 1788-1794 [Abstract] ( 281 ) [HTML 1KB] [ PDF 464KB] ( 964 )
1795 Effect of PE microplastics on soil water infiltration and suitability evaluation of infiltration model
LIU Zi-han, CAI Lu, DONG Qing-ge, ZHAO Xiao-li, HAN Jian-qiao
In order to explore the effect of microplastics(MPs) on soil water infiltration, five groups of MPs addition treatments (0,1,2,4,6g/kg) were set to study the effects of different MPs contents on wet front transport and cumulative infiltration volume through indoor soil column simulation, and evaluate the applicability of the main infiltration models in MPs contaminated soil. The results showed that the migration rate of wet front decreased first and then increased with the increase of MPs content. When the content reached T2 (MPs content was 2g/kg), the migration rate of wet front was the lowest, which was 0.146cm/min. Compared to CK treatment, the migration rate of T2treatment was 10.1% lower (P<0.05). The cumulative infiltration volume also decreased first and then increased with the increase of MPs content. When the content reached T2, the cumulative infiltration volume was the least, which was 14.68cm. The reason may be that with the increase of MPs content, the influence of MPs on soil permeability increases, and the influence is the greatest when it reaches T2; When the content continues to increase, a new infiltration channel is formed by the MPs to accelerate the infiltration although the soil permeability decreases. The wet front propulsion model, Kostiakov model and Philip model have good fitting effects, and the determination coefficient R2 are greater than 0.99, among which the wet front propulsion model has the best fitting effect. This study can provide a reference for the effect of MPs on soil water infiltration process and improve the simulation efficiency of the model.
2022 Vol. 42 (4): 1795-1802 [Abstract] ( 310 ) [HTML 1KB] [ PDF 772KB] ( 1737 )
1803 Effects of Iron-based silicon salts on fractions and transformation of cadmium and arsenic in soil environment
GUAN Di, WU Jia-mei, XIE Yun-he, CHEN Shan, CHEN Jin, PENG Hua, JI Xiong-hui
To explore the effects of iron-based silicon on the bioavailability and transformation of cadmium (Cd) and arsenic (As) in soil, laboratory long-term flooding cultivation culture adsorption experiment were carried out with Cd/As mild co-contaminated soil. Different proportions of Fe-Si materials and various iron-silicon salt (FS) components in combination with humic acid (FSC) and metal oxide (FSCa) were studied in the Cd-As soil. The morphological changes of Cd and As in the soil treated with the above complex agents were evaluated. The results showed that the ratio of iron to silicon was increased by 10%, the soil pH value was decreased by 0.35. Under F2-S8 treatment, ionized Cd in the soil was decreased by 71%. F10-S0 treatment reduced As ion state by 59.9%, and the content of ionized Cd and As were inversely proportional to the application ratios of iron salts and silicates. The intersection of Cd and As passivation rates between F4-S6 and F6-S4 was found to be between 25%~30%. Soluble Cd was the main compound of total Cd in soil, representing approximately 58%; As was mainly present in Fe-Al oxidation state and Ca binding state, accounting for 40% and 23% of total As, respectively. The ratios of iron to silicon from about 5.0:5.0 or 5.5:4.5 could effectively convert Al-bound As and Fe-Al oxide-bound As to Ca-bound As and residue state As. Meanwhile, soluble Cd can be converted into carbonate state Cd and Fe-Mn oxides state Cd. In conclusion, the bioavailability of Cd and As in soil can be simultaneously reduced by iron-based silicon compounds.
2022 Vol. 42 (4): 1803-1811 [Abstract] ( 285 ) [HTML 1KB] [ PDF 680KB] ( 1837 )
Environmental Microbiology
1812 Bacterial diversity and community composition in the Phragmites australis rhizosphere by cometabolism
HONG Zhi-feng, ZHANG Ni-chen, A Dan, QIU Rong-liang, LIN Qing-qi, NI Zhuo-biao, CHAO Yuan-qing
p-hydroxybenzoic acid (PHA), p-coumaric acid (PCA), caffeic acid (CA), and ferulic acid (FA) were selected as the representative phenolic root exudates (PREs), p-tert-butylphenol (PTBP) was chosen as the typical alkylphenol, and common reed (Phragmites australis) was used as the test plant. High-throughput sequencing and bioinformatics analyses were applied to investigate the variation of bacterial diversity and community by PRE-PTBP interaction in Phragmites australis rhizosphere. PREs could effectively improve the rhizosphere bacterial activity and accelerate the organic carbon degradation. However, the PTBP biodegradation could be promoted by monophenol PREs (PHA, PCA and FA), but not by polyphenol PREs (CA). On the one hand, PREs could decide the dominant bacterial phyla as carbon source: Proteobacteria and Bacteroidetes with high carbon source utilization ability increased by 15.34% and 4.73% in +PRE treatments, respectively; whereas Actinobacteria and Firmicutes with better detoxification/tolerance capacity increased by 15.92% and 9.99% in -PRE treatments, respectively. On the other hand, the functional structure of PREs could determine the functional bacterial genus: monophenol PREs (PHA, PCA and FA) are conducive to enrich monophenol-degrading bacteria, like Pseudomonas, accounting for 1.45%~4.02%; polyphenol PREs (CA) are favored to increase the abundance of polyphenol-degrading bacteria, like Novosphingobium, accounting for 3.71%. Furthermore, simple structure of PREs is beneficial for the enrichment of ASVs. The closer the PRE structure are, the more similar the ASV species will be. The community composition of rhizosphere bacteria in different treatments is not a random phenomenon, but a directional adjustment of rhizosphere microbiome by exudates released from plants.
2022 Vol. 42 (4): 1812-1818 [Abstract] ( 266 ) [HTML 1KB] [ PDF 785KB] ( 2068 )
1819 Characteristics on the community structure and abundance of diazotrophs from the soil profile in the Siding mine area
LI Yi, ZHANG Hai-chun, LIU Yuan, WEI Jiao-teng, WANG Cong, LIANG Ying, LIU Ke-hui, YU Fang-ming
In the present study, twelve soil profile samples (4 soil layers in each area) were collected from upstream, downstream and mine tailing areas in the Siding mine located in Liuzhou, Guangxi Province. The community composition, abundance and diversity of diazotrophs from the soil profile were examined using Illumina MiSeq high-throughput sequencing technology and fluorogenic quantitative real-time PCR technology. The results indicated that the phylum Proteobacteria was the most dominant taxon, with an abundance higher than 70%. Alphaproteobacteria was the dominant class in the soil profile from the upstream and downstream areas. The nifH gene abundance in the soil profile ranged from 3.02×106~1.17×107, 2.55×106~7.78×106and 8.19×105~3.14×106 gene copies/g (DW) in upstream, downstream and mine tailing areas, respectively. Nitrogen-related soil properties (including total nitrogen, ammonia and nitrate) and phosphorus-related soil properties (including total phosphorus and available phosphorus) were the main factors influencing nifH gene abundance. Soil lead, zinc and cadmium concentrations were found to mainly influence diazotrophic community composition. The Shannon index and ACE index of the diazotrophic community in upstream area were higher than those in the downstream and mine tailing areas, which indicated that the diversity and richness of the diazotrophic community in the soil profile were relatively higher in the upstream area. In addition, the soil potassium, calcium and sodium contents contributed to the ACE index and NMDS1index of the diazotrophic community to different degrees. Hence, the results indicated that variation in soil environmental factors had an impact on the community composition, abundance and diversity of diazotrophs from the soil profile. Our research will help to provide a scientific basis for nitrogen regulation, ecological restoration and reconstruction in mining areas.
2022 Vol. 42 (4): 1819-1828 [Abstract] ( 202 ) [HTML 1KB] [ PDF 1175KB] ( 599 )
1829 Roles of cyanobacterial-derived dissolved organic matter in mediating biodegradation of 17β-estradiol in water column
HUA Ke, JIANG Yu, WU Yuan-qiang, YANG Nan, LIU Xin
The effects of cyanobacterial-derived dissolved organic matter (COM) and its microbial processing on the biodegradation of 17β-estradiol (E2) in lake water column were investigated in this study. Through the simulated microbial ageing within a four-stage plug-flow bioreactor, five COM fractions with a gradient of decreasing bioreactivity were separated: S0 (78%) > S1 (67%) > S0 (36%) > S0 (13%) > S0 (1%). Within the 60 hours of batch incubation at dark, the addition of COM fractions at 8mgC/L exhibited strong acceleration on E2biodegradation, increasing the first-order kinetic rate with the order of S0 > S4 > S3 > S1 > S2. Microbial analysis further showed that the highly labile compounds in COM not only promoted the bacterial growth but also maintained the diverse microbial community in the S0-amended group. In comparsion, the bacterial concentration and E2biodegradation rate in the S1- and S2-amended groups was remarkably lower, meaning that the semilabile and recalcitrant compounds were unable to serve as effective carbon sources. However, the enriched aromatic, humic structure in the S3- and S4-amended groups significantly increased the biomass-normalized E2biodegradation rate, possibly due to the selection of potentially E2-degrading bacteria and the activation of catabolic enzymes under carbon-limited conditions. The environmental behavior and fate of estrogens in eutrophic waters are closely related to the bioreactivity of COM.
2022 Vol. 42 (4): 1829-1836 [Abstract] ( 225 ) [HTML 1KB] [ PDF 643KB] ( 859 )
Environmental Ecology
1837 Distribution of water and TN loads in buffer strips under different rainfall characteristics
XIONG Li-jun, WU Jian-qiang, HUANG Shen-fa
On-site monitoring, mass balance, correlation analysis and other tools were adopted to investigate the correlation between water distribution and rainfall/soil factors, and then determine the partition coefficients between water and TN pollution load removal at three typical vegetation buffers. The results showed that runoff at outlet of strips was highly positively correlated with rainfall depth (0.980~0.987, P<0.01), and seepage was significantly positively correlated with rainfall depth and rainfall duration (0.595~0.828, P<0.01). The average runoff coefficients under moderate rain, heavy rain and storm were 0.10, 0.36 and 0.72, and the average interception coefficients of TN load were 11.0, 8.2 and 4.5mg/(m2·mm) respectively. The removal effects of runoff and TN load decreased with the increase of rainfall depth. Under moderate-heavy rain and storm, the water distribution of vegetation buffer strips was mainly characterized with seepage (coefficient: 0.48~0.71) and runoff at outlet (coefficient: 0.69~0.74). The TN load removal by vegetation buffer strips under moderate rain, heavy rain and rainstorm was mainly characterized with soil infiltration, accounting for 56%, 44% and 20% of the inflow-load respectively. The vegetation with stems and leaves covering the ground and fine roots had better effect on water and pollution removal for Farmland Runoff and its pollution. The buffer strips planted with Cynodon dactylon had the best removal effect on water and Trifolium repens L had the best removal effect on TN load, up to 60% and 61% respectively. Even in the plain river network area with high groundwater level, the soil infiltration of vegetation buffer strips still greatly contributes to the runoff and TN load reduction, especially in the areas with high frequency of rainfall less than 50mm. The results provided data support for the differential evaluation of runoff pollution reduction under the influence of rainfall and vegetation, and worth referencing for the control of runoff pollution by buffer strips under different rainfall characteristics.
2022 Vol. 42 (4): 1837-1846 [Abstract] ( 213 ) [HTML 1KB] [ PDF 1608KB] ( 1059 )
1847 Hydrolochemical characteristics and spatial-temporal variations of groundwater in the Liangshui River basin, Beijing
LI Jie, JIANG Ying, LIU Yu-lian, JIANG Ya, TENG Yan-guo
We present a case from Liangshui River catchment to investigate and quantify the reasons for these changes. Results indicate that the groundwater with poor quality are limited at depths less than 100m. Shallow groundwater and river samples plot on the same meteoric water line, which indicates river seepage is one of the important controlling factors for groundwater quality. Meanwhile, the hydrogeologic structure of the study area indicates the groundwater is primarily recharged from river seepage in upper alluvial-proluvial plain, which should be considered an important protected region. Antropogenic contamination added about 435mg/L both in the river and shallow groundwater. Although groundwater pollution is observed at shallow depths, the trend is likely in stable state indicated by the steady TDS values over the most recent seven years. In order to mitigate groundwater pollution, limits on pumping phreatic aquifer water and channel anti-seepage treatment measures are put forward for consideration.
2022 Vol. 42 (4): 1847-1853 [Abstract] ( 295 ) [HTML 0KB] [ PDF 1029KB] ( 1430 )
1854 Interception experiment of nutrient-laden cohesive sediment imported from river channel into Lake Taihu
HE Xiang-yu, YAN Wen-ming, WU Ting-feng, YANG Teng-teng, HU Run-tao
The sediment trap experiment was conducted at the estuary of Dapu River to study the feasibility of using sediment trap to reduce the exogenous sediment and nutrients into Lake Taihu. The results showed that the sediment trap could effectively collect the exogenous sediment and the nutrients carried by the river. The sediment trap was deposited at an average rate of -33.99m3/month, and the maximum monthly sedimentation (66.34m3) appeared in September. The annual-averaged collection of suspended solids, total nitrogen, and total phosphorus were 407.89m3, 236.91kg, 36.46kg, respectively. The sediment and nutrients collected by the sediment trap mainly came from the Dapu River, which mainly came from locals in the center observation station. Correlation analysis showed that the sediment trap’s intercepting capacity for total phosphorus was better than that of total nitrogen. Therefore, this paper proposed to excavate sediment traps along the shoreline of the west bank of Lake Taihu, where the estuaries were the densest, which could effectively reduce the load of exogenous sediment and nutrients in Lake Taihu. This study provided a new method for the problem of eutrophication in Lake Taihu.
2022 Vol. 42 (4): 1854-1860 [Abstract] ( 202 ) [HTML 0KB] [ PDF 729KB] ( 823 )
1861 Impact of infiltration of ecology water replenishment of the Yongding River on groundwater quality and the mechanism
ZHAI Yuan-zheng, JIANG Ya, XIA Xue-lian, PAN Cheng-zhong, HU Li-tang, WANG Jin-sheng, TENG Yan-guo, HAN Yi-fan
The problems of river flow reduction, water ecological degradation and so on affected by the climate changes and human activities have attracted extensive attention. It’s considered to be the quickest and the most effective means to alleviate or solve these problems by means of artificial recharge such as water diversion. After the water is recharged into the river, some of it will infiltrate through the riverbed to recharge the underlying groundwater. Affected by the quality of the water source and the water-rock interaction in the infiltration, the leakage recharge of the water into the groundwater may change the groundwater quality, which has become a problem worthy of attention. Taking the ecology water replenishment of the Beijing section of the Yongding River in 2019~2020 as an example, this study studied the impacts of the river water infiltration on the groundwater quality through the indoor mixing test and the leaching test. The results show that, the species of the hydrochemical indicators of the water do not change compared with those before the infiltration, the impact of the water-rock interaction on the concentrations of these indicators is also relatively limited, and the content levels of the indicators are generally between those of the river water and the groundwater. The impact of the infiltration on the groundwater quality is fundamentally determined by the quality difference between the river water and the groundwater and the infiltration volume of the river water. That is, the greater the quality difference and the greater the infiltration volume, the more obvious the impact will be; otherwise, the weaker the impact will be. Due to the good quality of the recharge water source of the Yongding River, the impact of the ecology water replenishment of the river on the groundwater quality is generally acceptable, and it can improve the “bottleneck” indicators (such as nitrated nitrogen) affecting the groundwater quality to a certain extent.
2022 Vol. 42 (4): 1861-1868 [Abstract] ( 284 ) [HTML 0KB] [ PDF 627KB] ( 1386 )
1869 Effects of microbial communities on phosphorus speciation in lakeside sediments of Caohai Lake
LONG Yun-chuan, JIANG Juan, HU Jing, ZHANG Zhen-ming, ZHU Cheng-bin, SU Rong-xiang, ZHOU Shao-qi
To explore the effect of the microbial community on phosphorus speciation in the sediment from plateau lake, the lakeside sediments from Caohai were collected, then the phosphorus speciation was analyzed, and the community compositions of bacteria and archaea were investigated using high-throughput sequencing. The results showed that the total phosphorus content in the sediments ranged from 662.89 to 881.26 mg/kg, with an average of 750.36mg/kg. Among the phosphorus fractions, NaOH- NRP>Res-P>BD-P>HCl-P>NaOH-SRP>NH4Cl-P. The bacterial community consisted of 59 phyla (dominated by Proteobacteria) and 1259 genera (dominated by Thiobacillus and Anaeromyxobacter). The archaeal community consisted of 8 phyla (dominated by Crenarchaeota) and 67 genera (dominated by Methanosaeta). The redundancy analysis, principal component analysis, and co-occurrence network analysis revealed that the microbial community could drive the transformation of the phosphorus speciation in lakeside sediments from Caohai. The bacteria affected the phosphorus species mainly through regulating the activity of alkaline phosphatase and the oxidation/reduction of iron, while the archaea impacted it by changing organic matter and acid phosphatase.
2022 Vol. 42 (4): 1869-1876 [Abstract] ( 283 ) [HTML 0KB] [ PDF 1531KB] ( 1154 )
1877 Water quality alert with automatic monitoring data based on MSLSTM-DA model
JI Xiao-yan, YAO Zhi-peng, YANG Kai, CHEN Ya-nan, WANG Zheng, AN Xin-guo
A multivariate stacked long and short term memory network-difference analysis (MSLSTM-DA) model is proposed to alarm surface water quality abnormal data. Established the MSLSTM model to predict the water quality data, and then established the DA model based on the residual distribution of the prediction results to determine the threshold value of each indicator, and alerted the data when the difference between the measured data and the predicted data is greater than the threshold value. The validity of the method was verified using water quality data from the Yangtze River basin monitoring sections. The results showed that the mean values of MAE and MAPE for five indicators were 21.0% and 17.8% lower than those of BP neural network prediction model, and 16.8% and 17.9% lower than those of LSTM model. The mean value of Pearson coefficient was 5.9% and 4.4% higher than that of BP neural network and LSTM model. 37 abnormal water quality data were detected for the 5 indicators, 34 of which were judged to be abnormal by manual judgment, with an alarm accuracy rate of 91.9%.
2022 Vol. 42 (4): 1877-1883 [Abstract] ( 251 ) [HTML 0KB] [ PDF 730KB] ( 1565 )
1884 Distribution and influencing factors of vegetation mercury in major forest systems across the globe
LI Xin, CHANG Shun-li, WANG Xun, YUAN Wei, ZHANG Yu-tao
Based on the studies on the global mercury cycling processes in forests over the last 20-year, this study aims to elucidate the vegetation mercury distribution and its influencing factors in major forest types globally through meta-analysis. Results showed that the descending order of mercury concentrations in vegetation (in terms of median value) was litterfall (38.9ng/g) > foliage (24.1ng/g) > root (18.5ng/g) > bark (13.2ng/g) > branch (12.0ng/g) > stem (3.1ng/g). Litterfall was highly significantly correlated with foliage Hg concentration (rho=0.747, p<0.01, rho: Spearman's correlation coefficient, depending on number of samples, hereafter), and a significant correlation (rho=0.265, P<0.05) between leaves and trunks, but no correlations among the rest of tissues (p>0.05). The above correlations are mainly controlled by the uptake of atmospheric elemental mercury by foliage and the upward transport from foliage to the xylem of trees. In addition, vegetation Hg concentrations in broadleaf evergreen forest leaves (median: 56.0ng/g, below) were higher than those in coniferous (25.5ng/g), broadleaf deciduous (23.0ng/g), and mangrove (18.6ng/g) forests. This is because the combined effects of stomatal conductance, stomatal number, leaf area and leaf longevity lead to the evergreen broadleaf forests with the greatest capacity for mercury enrichment. this study showed a significant inter-regional variation in vegetation Hg concentrations (e.g., up to range of 0.90~225ng/g). This can be attributed to the inter-regional differences in vegetation type and atmospheric mercury concentrations. This study provides important data and expanded our understanding to further quantify the global forest vegetation Hg pool and sink.
2022 Vol. 42 (4): 1884-1891 [Abstract] ( 315 ) [HTML 0KB] [ PDF 698KB] ( 1243 )
Environmental Toxicology and Health
1892 Study on ecological toxicity of microplastics and cadmium interaction on wheat seed germination
FENG Tian-zhen, CHEN Su, CHEN Ying, LIU Ying, ZHANG Xiao-ying, CHAO Lei
In order to identify the behaviors of microplastics, heavy metals and their combined action on the growth characteristics of crop seeds, wheat (Triticum aestivum L) was selected as the experimental subject to conduct the research on the soil enriched microplastics polyethylene (mPE), polypropylene (mPP) (0, 10, 50, 100, 200, 500, 1000, 5000 and 10000mg/kg) and heavy metal cadmium (Cd) (0, 1 and 5mg/kg) single pollution toward seed germination respectively following by their combined effect. From the results derived from single pollution condition of Cd, low concentration of Cd exhibit promoted wheat germination accompanied by inhibition effect on high Cd concentration. Furthermore, both root and bud length displayed the inverse correlation with the Cd concentration. Under the single pollution condition of microplastic, the germination rate of mPE to wheat seeds basically showed a valley type that demonstrated two end are inhibited and medium concentration of mPE can promote the germination rate of wheat seeds. And low concentration of mPP exhibit promoted wheat germination accompanied by inhibition effect on high mPP concentration. In the experiment of microplastic and Cd combined pollution, the experiment result showed that microplastic and Cd compound pollution promoted elongation of wheat root and bud when compared to a single microplastic pollution control group. Under combined pollution, mPP promoted wheat root elongation and bud elongation more than mPE, and the concentration range was wider (0~1000mg/kg). The length of root and bud of wheat seeds contaminated pollute under mPE and Cd pollution (1mg/kg) was longer than that under mPE and Cd pollution (5mg/kg), but under the same conditions, the length of root and bud of wheat seeds contaminated with mPP and Cd pollution (1mg/kg) was shorter than that under mPP and Cd pollution (5mg/kg). The combined effect of microplastics and Cd on the germination, root and bud length of wheat seeds is generally shown as an accelerating effect, which relieves the toxic effect of a single pollutant to a certain extent.
2022 Vol. 42 (4): 1892-1900 [Abstract] ( 388 ) [HTML 0KB] [ PDF 918KB] ( 2412 )
Carbon Emission Control
1901 The economic impacts of introducing auction into carbon allowance allocation mechanism in the national carbon market: Simulation based on CGE model
ZHANG Ning, PANG Jun, FENG Xiang-zhao
Differentiated policy scenarios based on the CGE model features an electricity sector subdivision designed in this paper, to address the introduction of the quota auction, whether the carbon tax should be implemented, and the setting of carbon emission reduction targets. On this basis, the impacts of different designs on carbon market and macroeconomic performance analyzed this paper. Results showed that the introduction of quota auction mechanism could help to decrease carbon price, enlarge the carbon market scale, and spur the vitality of the carbon market. In addition, carbon intensive industries were the principal participants in the auction market; and the auction mechanism could restrain the development of industries covered by national carbon market, especially thermal power industry, and promote electricity outputs of the clean power industries. However, compared to the totally free allocation of carbon allowances, the introduction of quota auction mechanism impacted the GDP growth more negatively. Levying carbon tax on industries outside the carbon market could further reduce the carbon price, increase the trading volume of carbon allowance, mitigate the negative impacts on the GDP growth, and increase government revenues. China should introduce the quota auction mechanism into the national carbon market in due course and implement carbon tax as a complementary measure. The proportion of carbon allowance allocated by auction needs to be gradually increased based on the consideration of the effectiveness of carbon market and economic affordability.
2022 Vol. 42 (4): 1901-1911 [Abstract] ( 458 ) [HTML 0KB] [ PDF 552KB] ( 1331 )
1912 Peaking characteristics and enlightenment based on carbon peak countries
ZHANG Nan, ZHANG Bao-liu, LÜ Lian-hong, BAI Zi-han, ZHAO Ming-xuan, LUO Hong
The paper is based on the World Bank World Development Indicators database from 1960 to 2020, and Mann-Kendall test and Spearman's Rho test are used to analyze trends in CO2 emissions and socioeconomic data of 219 countries and regions around the world. The result shows: the conclusions of the MK test and the SR test are consistent that 42 countries and 1 economic alliance achieved carbon peak, while 46 countries are in the carbon peak plateau. Most peaking countries have the following characteristics: GDP per capita is between 2x104 and 5x104 dollars; tertiary industry accounts for more than 50%; fossil energy consumption still accounts for more than 60%; carbon emissions are in the downward phase of the Environmental Kuznets Curve, and economic development is decoupled from carbon emission. Learning from the experience of the peaking countries, China should further adjust energy structure, increase the proportion of renewable energy consumption, optimize the industrial structure, accelerate the construction of a new pattern of the national economy dominated by the service industry, formulate regionally differentiated carbon peak goals, and promote qualified regions to take the lead in reaching the peak.
2022 Vol. 42 (4): 1912-1921 [Abstract] ( 349 ) [HTML 0KB] [ PDF 553KB] ( 1745 )
1922 Study on the emission reduction effect of China's carbon trading pilot policy and regional differences
ZENG Shi-hong, LI Fan, WENG Zhi-xiong, ZHONG Zhen
Based on a continuous difference-in-difference model, this study evaluated the emissions reduction effect and regional variation and the mechanism of China's carbon trading pilot policies from 2004 to 2017. The results showed that the carbon trading policy could reduce the carbon intensity of the pilot areas by 9.5%, and every 1% increase in the size and activity of the carbon market brought about a 0.9% and 0.7% reduction in the carbon intensity of the pilot areas, respectively. In terms of heterogeneous impact, the carbon trading policy had a significant emission reduction effect on the east and central regions while it had no significant impact on the western areas. Further, the carbon trading policy had a significantly higher impact on carbon reduction in developed provinces than in developing provinces in China. The carbon emission reduction effect was mainly achieved by implementing influence on the enterprises participating in the market. In addition, the carbon trading policy had a synergistic pollution reduction effect, reduced sulfur dioxide emissions by 22.7% in the pilot areas. Therefore, it is necessary to accelerate the national carbon market and increase the level of carbon market activity. While it is also necessary to smooth emission reduction channels, and promote the synergistic emission reduction of carbon dioxide and other pollutants.
2022 Vol. 42 (4): 1922-1933 [Abstract] ( 246 ) [HTML 0KB] [ PDF 544KB] ( 1975 )
1934 Study on CO2 reduction of cement with fly ash substitute from the perspective of life cycle in China
XIAO Jing, LIANG Xue-min, ZHANG Yi-chang, ZHANG Yue-ling
The CO2 reduction induced by material in the situation of fly ash replacement is calculated by the guideline of Greenhouse Gas Emissions of Chinese Cement Enterprises. Meanwhile, the CO2 reduction induced by energy employment also defined by the methods from Intergovernmental Panel on Climate Change. The results show that considering industrial symbiosis with coal-fired power plants, 92.676kg/t cement of CO2 are reduced. It is demonstrated that the replacement of clinker with fly ash is the main part leading to CO2 reduction in China's cement industry. When combined with the replacement of raw materials, the maximum CO2 reduction per ton of cement can be up to 373.303kg. In the application stage, the carbonization effect of concrete formed by fly ash and Portland cement has increased, and one ton of cement will adsorb 192.015kg of CO2 by 2050. In the context of fly ash replacement, the emission reduction caused by the change of waste heat generation and the clean electricity employment with different proportion are forecasted. It is found that the measure can also effectively promote the achievement of carbon peak and neutrality goals.
2022 Vol. 42 (4): 1934-1944 [Abstract] ( 357 ) [HTML 0KB] [ PDF 863KB] ( 1647 )
1945 Spatio-temporal patterns of CO2 emissions from energy consumption and vegetation carbon sequestration in China under the emission peak and carbon neutrality
LI Cheng, YANG Shu-hui, WU Fang, XU Yang, CUI Xue-feng
In order to understand the variation characteristics of CO2 emissions from energy consumption (ERCE) and vegetation carbon sequestration (VCS) in China, dynamic changes and spatial patterns of the ERCE and VCS were quantitatively analyzed from 2000 to 2017 based on multi-source data, including meteorological, satellite, land cover, and statistical data, at the national, provincial, and county scales. Moreover, a carbon pressure index (CPI) was proposed to characterize the relationship between the ERCE and VCS. The ERCE and ERCE per capita had a significant increasing trend between 2000 and 2017 (P<0.01), but both displayed a slight downward trend after 2013 and 2012, respectively. As for spatial patterns, higher increasing trends were found in the northern and eastern China. Both VCS and VCS per capita had a rapidly increasing trend after the year of 2010 (P<0.01), with a trend value of 148.09×106t/a and 0.04t/(person·a), respectively. Particularly, the VCS and VCS per capita displayed larger increasing trends in the northeast region, southwest region, and the Loess Plateau. Nearly 1/3 of all provinces of China had a higher mean value of CPI exceeding 1in China, which meant that the ERCE was higher than VCS. Among them, the relative higher CPI values were found in Shanghai, Tianjin, Jiangsu, Shandong, and Ningxia, and higher increasing trends of CPI were also found in these regions, which indicated that these regions had greater pressure to reduce carbon emissions. The findings can provide an important reference for developing low-carbon policies in different regions of China.
2022 Vol. 42 (4): 1945-1953 [Abstract] ( 335 ) [HTML 0KB] [ PDF 2052KB] ( 1674 )
Environmental Impact Assessment and Management
1954 Research status and prospect of long-term environmental safety and life prediction of solid waste landfill
XU Ya, SUN Shu-na, WANG Qi, LIU Yu-qiang, CHEN Hong-wei, PENG Xiang-xun, YANG Feng
China had a large number of solid waste landfills, low operation level, fast aging of facilities, short life expectancy and serious aging after life expiration. In contrast, there were some problems in the research on the life of solid waste landfill, such as less attention, unclear research direction, unsystematic research content and so on. In this regard, according to the idea from general to special, this paper first summarized the basic concepts and development process of life prediction in general engineering field, and sorted out the main research objects and research methods of engineering life prediction; On this basis, combined with the engineering and practical characteristics of solid waste landfill, this paper systematically describe the main mechanism and prediction method of material performance degradation of solid waste landfill, the evaluation method of overall landfill performance, and put forward the shortcomings of current research and further work. The main conclusions were as follows: the research on general engineering life covers all fielded of national production and life. The research objects include mechanical equipment, construction engineering, and various general materials and parts. Three engineering life prediction methods based on Systematics and decision theory, simulation model and empirical method were formed; At present, in the field of solid waste landfill, the aging mechanism and aging prediction method of HDPE membrane impervious materials and guide and discharge medium materials were basically clarified, the overall performance prediction method of landfill was formed, and the long-term performance evolution prediction research of solid waste landfill was carried out by coupling the overall performance prediction model and material aging prediction model. Finally, the paper pointed out that the life prediction research of solid waste landfill engineering should be strengthened and improved, including improving the basic theory and framework system of life prediction theory system, deeply carrying out the research on the aging mechanism and prediction method of core materials under extreme service conditions, carrying out the research on the prediction technology of middle and late life (residual life), and strengthening the application research of life prediction.
2022 Vol. 42 (4): 1954-1962 [Abstract] ( 339 ) [HTML 0KB] [ PDF 489KB] ( 2029 )
1963 Landscape ecological risk assessment in Weibei dryland region of Shaanxi Province based on LUCC
WEI Fang, LIU Jing, XIA Li-heng, LONG Xiao-cui, XU Zhong-wei
This study constructed a landscape ecological risk evaluation model based on land use/land cover change and evaluates the ecological risk status of the Weibei dryland region from 1980 to 2018. The results showed that: With the rapid expansion of towns and cities and the growth of land development and utilization intensity, different land use types have changed to different degrees, among which, arable land decreased the most, with a total decrease of 636.36km2, while construction land increased the most, with a total increase of 496.17km2. Influenced by factors such as population growth and the implementation of the policy of returning farmland to forest and grass, a total of 3492.40km2 of land in the Weibei dryland region was converted, with a change ratio of 8.80%. The advantage of transfer between farmland, forest land, grass and construction land was most obvious, with a conversion area of 3177.22km2, accounting for 90.98% of the total transformed area. During the study period, the proportion of low and medium-low risk areas decreased from 20.23% to 19.01%, the proportion of medium-risk areas increased from 41.62% to 43.23%, and the proportion of medium-high and high-risk areas decreased from 38.15% to 37.77%, with an overall high ecological risk level, showing the distribution characteristics of "low around, high in the middle". In addition, the mean value of ecological risk in the study area shows a fluctuating trend of increasing and then decreasing, and the overall ecological safety has improved, but the quality of ecological environment in some areas has decreased. The global Moran's I index of the landscape ecological risk values of the five time nodes in the study area were all higher than 0.55, indicating a spatially significant positive correlation of ecological risk values. The "high-high" concentration areas are mainly located in the medium-high and high-risk areas, where the ecological environment has been more seriously damaged due to large-scale disturbance by human activities.
2022 Vol. 42 (4): 1963-1974 [Abstract] ( 277 ) [HTML 0KB] [ PDF 2346KB] ( 1167 )
1975 Life cycle assessment of lithium iron phosphate battery in different utilization scenarios
JIAZhi-jie, GAO Feng, DU Shi-wei, SUN Bo-xue
In order to evaluate environmental impact of cascade utilization fromlithium iron phosphate (LFP) batteries,two utilization scenarios, direct utilization scenario and cascade utilization scenario, were set in this article. The environmental impact and contribution of each stage in both of utilization scenarios were analyzed based on life cycle assessment (LCA)methodology.With a life cycle of 800times, 1GWh LFP battery used in energy storage battery for the communication base station (CBS) was set as the function unit. The key points of environmental impact from the two utilization scenarios were the energy storage utilization stage, accounting for 58.25% and 64.03% of the total environmental impact respectively. The environmental impact from the manufacturing stage was also significant, accounting for 41.58% and 27.36%, respectively. The contribution to the total environmental loads from the recovery and regeneration stage was 0.18% and 0.14%, respectively. The environmental benefits fromthe lithium recycling were offset by the environmental loads fromthe additional resources and energy consumption initsrecycling process. The results from the comparing the environmental impactof the two utilization scenarios revealed that the cascade utilization scenario reduced the total environmental impact by9.03%, which is more environmentally friendly compared to the direct utilization scenario. Furthermore, the contribution structuresof the resource consumption, energy consumption and greenhouse gases emission in the two scenarios were analyzed. The results indicated that the manufacturing stage and the energy storage utilization stagecontributed significantly to these three indicators.
2022 Vol. 42 (4): 1975-1984 [Abstract] ( 511 ) [HTML 0KB] [ PDF 705KB] ( 2700 )
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