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  Current Issue
 
2023 Vol.43 Issue.9,Published 2023-09-20
Air Pollution Control
Water Pollution Control
Soil Pollution Control
Environmental Ecology
Environmental Impact Assessment and Management
Carbon Emission Control
Emerging Contaminants and Environmental Toxicology
Air Pollution Control
4450 Analysis of sand and dust storm transport paths characteristics and meteorological causes in China from 2000 to 2021
XU Ran, ZHANG Bi-hui, AN Lin-chang, LI Lei, CHI Xi-yuan, JIANG Qi
Based on the analysis of the ground data from 673 dust observation stations in China and meteorological conditions over the past 22 years, the evolution and transmission characteristics of sand and dust (SDS) weather processes in northern China, as well as the effects of changes in meteorological factors were determined. The frequency and intensity of SDS events in Northern China during 2000 to 2021 showed a decreasing trend. SDS events in spring accounted for 77.8%, of which nearly 40% occurred in April, significantly higher than other months. Among the five typical transmission paths, the northwest path, the western path, and the northern path types were the most important, accounting for 38.5%, 32.9% and 18.2%, respectively. Meanwhile, the transmission path of dust in spring has the characteristics of staged distribution. From 2000 to 2006, the northwest path was dominant. During the transition period from 2007 to 2013, the transition period showed an increasing trend in the western path and a decreasing trend in the northwest path until the two were equally proportioned. After 2014, the western path was adjusted to become the main transmission path for spring dust weather for spring SDS weather. In addition, the spring climate has turned to ‘warm and humid’ type, and East Asian SDS has generally weakened. However, the center of the Asian polar vortex gradually moved westward and northward, moving to the east of Novaya Zemlya. There was a strong sea-level pressure gradient between Northwest Asia and Central Asia, and the low-level wind speeds in the main dust sources in the central and eastern parts of Northwest China continued to increase, which was conductive to the increase of western path SDS events.
2023 Vol. 43 (9): 4450-4458 [Abstract] ( 567 ) [HTML 1KB] [ PDF 12727KB] ( 2409 )
4459 Effects of biomass burning in Southeast Asia on pollution transport in Yunnan border area
RAO Xiao-qin, ZHANG Bi-hui, JIANG Qi, WANG Ji-kang, CHI Xi-yuan, YOU Yuan
Causes of air quality deterioration over southern Yunnan, China in early spring 2019 were analyzed by using multi-source data such as meteorological ground observation, sounding data, NCEP reanalysis data, atmospheric composition observation and satellite fire monitoring. And the sources and transmission paths of pollution were also analyzed by WRF-CAMx numerical model and HYSPLIT backward trajectory. Results showed that the peaks of PM2.5 concentrations during two continuous pollution processes from March 24 to 29 (P1) and from March 31 to April 3 (P2) occurred in Xishuangbanna, a border city in Yunnan province, were 168 and 178μg/m3, respectively. From March 24 to April 3, the mean PM2.5 concentration was 105.4μg/m3, which was 116% higher than the value during the same period from 2015~2018. But it’s atmospheric diffusion and wet clearance conditions were similar to or slightly preferred to the same period from 2015~2018. This indicated that local meteorological conditions were not the direct cause of air quality deterioration this time. During the pollution period, PM2.5 and CO concentrations showed a significant positive correlation (R2=0.72), with typical biomass burning characteristics. Cluster and source analysis simulation showed that high concentration pollutions from biomass burning in Thailand and Myanmar were transported to the border of China, which was an important cause of abnormally high pollutant concentration in southern Yunnan. And the pollutions were mainly transported from the west, southwest and south directions. In P1, Myanmar contributed about 48% and Thailand contributed about 39%. In P2, Thailand contributed about 50% and Myanmar contributed about 30%. Since the height of pollution transmission was below 1500 meters, this led to the accumulation and growth of pollutants in the low-altitude piedmont areas of southern Yunnan but had little impact on that in high-altitude areas of central and northern Yunnan.
2023 Vol. 43 (9): 4459-4468 [Abstract] ( 180 ) [HTML 1KB] [ PDF 2164KB] ( 2337 )
4469 Simulation of aerosol radiative forcing based on blue sky albedo
WANG Heng-yang, LI Xiang-chen, WANG Shuang, TANG Hong-zhao
This article calculated the blue sky albedo using MODIS shortwave Black Sky Albedo (BSA) and White Sky Albedo (WSA) data combined with the 6S radiation transfer model simulated sky scattering light proportion factors. Based on the aerosol optical depths (AOD), particle size distribution, and complex refractive index data from the AERONET station in Baotou, the 6S radiation transfer model was used to simulate the surface (SFC) and top of atmosphere (TOA) ARF from 2018 to 2021. The differences between different types of albedos (BSA and WSA) and different aerosol models ARF and the true ARF were compared. The results showed that the average TOA ARF was (1.54±3.8)W/m2, and its value was related to the surface albedo and single scattering albedo (SSA). The continental and urban TOA ARF were positive values, about 2.2 and 8.6 times the real value, respectively. The desert TOA ARF was mostly negative, and in some months with large albedo, it was positive. The average SFC ARF was (-30.39±9.5)W/m2, with lower absolute values in summer and autumn. The continental, urban and desert SFC ARF were about 1.1, 1.76 and 0.77 times the real value, respectively, and different aerosol models had little effect on SFC ARF. The results of the three wavelengths method simulation of black carbon (BC) ARF showed that the average SFC and TOA BCARF were (-6.82±4.3)W/m2 and (2.23±1.5)W/m2, respectively, and SFC BCARF accounts for 7.3% to 40.4% of the total SFC ARF, with a higher proportion in summer.
2023 Vol. 43 (9): 4469-4477 [Abstract] ( 200 ) [HTML 1KB] [ PDF 989KB] ( 1651 )
4478 Research on dynamic discharge characteristics of inland river vessels based on data restoration-An example in Chongqing
LIU Kui, ZHANG Xue-ting, YAO Da-wen, YANG Xin-ru, LIU Yong-hong
As the emission inventories of inland ships usually do not consider the static parameters and trajectories of ships, this paper corrects the ship static parameters based on the XGboost algorithm and improves the long-distance trajectory data using channel trajectories. Then the emission inventories of ships in Yangtze River in Chongqing are calculated based on the repaired data, and the spatio-temporal characteristics of ship emissions are analyzed. Research results show that the proposed method performs excellently in data restoration of inland ships, with R2=0.963 for the main engine rated power restoration, and R2=0.871 for the design speed restoration. Moreover, the full trajectory is incorporated and the repairing time is greatly reduced, which provides data support for ship emission calculation. The results further show that the total emissions of pollutants from inland river ships in Chongqing are 1869.01 tons, in which NOx emissions accounting for the highest proportion of all pollutants. The main sources of pollutions in the water area are dry bulk ships and passenger ships. The order of emissions under different driving conditions is as follows: cruising>parking>maneuvering. The emission characteristics of passenger ships are different from those of other ship types. The peak of passenger ships emissions occurs at night, while other types of ships reach their emission peaks during the day. The spatial emission characteristics of different ships are different. Container ships and dangerous goods ships generate emissions on the main line of the Yangtze River, while passenger ships have high emissions concentrated in passenger terminals.
2023 Vol. 43 (9): 4478-4489 [Abstract] ( 216 ) [HTML 1KB] [ PDF 1265KB] ( 1708 )
4490 Development and characteristics of vehicle emission inventory with high spatiotemporal resolution in Jiangsu Province
SUN Shi-da, WANG Bo, SUN Lu-na, HUANG Xu, WANG Xing-xing, ZHANG Shi-da, BO Yu
In this study, the traditional methodological framework was systematically optimized by considering month-by-month emission calculation, mileage weighting, and traffic data integration to address the low spatiotemporal resolution associated with the top-down method of establishing vehicle emission inventory. Based on this, the vehicle emission inventory in Jiangsu Province in 2018 was developed, and the structural level characteristics, socio-economic correlation, and spatiotemporal distribution of emissions were analyzed. Vehicle emissions of CO, VOCs, NOx, and PM2.5 in Jiangsu Province were 839.97, 166.80, 617.16, and 21.15kt, respectively, in 2018. CO and VOCs were mainly contributed by gasoline cars, while NOx and PM2.5 were mainly contributed by heavy-duty diesel trucks. Higher emission contribution was exhibited by vehicles that met China 3 (or below) standard than their vehicle population shares, and vehicle emissions in winter were higher than in other seasons. At the city level, vehicle emissions were concentrated in Suzhou, Wuxi, Nanjing, Xuzhou, Nantong, Lianyungang, and Changzhou, and the correlation between CO and VOC emissions per capita and road emissions intensity was higher than that of NOx and PM2.5. Vehicle emissions were highly correlated with GDP and the size of the built-up area. Vehicle CO and VOC emissions were concentrated in the urban area, while NOx and PM2.5 emissions were distributed in strips. Additionally, the "two peaks and one valley" characteristic was demonstrated by the temporal profile of daily emissions.
2023 Vol. 43 (9): 4490-4502 [Abstract] ( 192 ) [HTML 1KB] [ PDF 4219KB] ( 1628 )
4503 Numerical prediction technology of extended period PM2.5 in autumn and winter in Tianjin based on Nudging method
TANG Ying-xiao, QIN Ming-yue, CAI Zi-ying, YANG Xu
Based on the Tianjin extended period Air Quality Numerical forecasting system (CFS/WRF-Chem), this study introduced Nudging technology to restrict the model integration process, and conducted sensitivity experiments by Grid Nudging and Spectral Nudging. Through the optimization scheme experiments of parameters such as Nudging wave number, Nudging time and Nudging variables, the improvement applicability of Nudging technology in the extended period PM2.5 numerical prediction to effectively enhance the accuracy of air quality trend prediction for 10~45 days in autumn and winter in Tianjin. The results showed that: Compared to the extend period numerical model prediction without Nudging technology, no matter the Grid Nudging or Spectral Nudging, prediction improved after using Nudging technology. The correlation coefficient between daily prediction and observed PM2.5 concentration increased from 0.1without Nudging technology to 0.35 by Grid Nudging and 0.43 by Spectral Nudging, and the prediction accuracy of PM2.5 grade increased from 33% to 47% and 44%, respectively. Compared to the selection of Grid Nudging and Spectral Nudging scheme, the optimal configuration of parameters such as Nudging wave number, Nudging time and Nudging variables, was more critical to the application of Nudging technology. In Grid Nudging, the best prediction was the experiment by Nudging coefficient was 5×10-5, Nudging time was 6h, and Nudging variable was θ-q-uv. In Spectral Nudging, the best prediction is the experiment by Nudging wave number was 1, truncated wavelength was 1800km, and Nudging variable was θ-q-uv. Even using Nudging technology, there are still great uncertainties in the extended period daily PM2.5 concentration prediction, which is more suitable for trend prediction (increase or decrease). According to the analysis of the PM2.5 concentration trend between pentads, the prediction accuracy was 50% without Nudging technology, and increased to 75% by Grid Nudging, and 88% by Spectral Nudging. Spectral Nudging provided a slightly better prediction, which could effectively support the extended period PM2.5 trend prediction by pentad resolution.
2023 Vol. 43 (9): 4503-4511 [Abstract] ( 225 ) [HTML 1KB] [ PDF 1046KB] ( 1329 )
4512 Characteristics and influencing factors of black carbon aerosol in Mountain Lushan
LIU Cheng, DENG Li-chen, QIAN Yue, YAN Ai-jun, FANG Xiao-zhen, PAN Yuan-yuan, GUO Wei, XIE Ya-jun
The characteristics, influencing factors and sources of black carbon (BC) aerosol in Mt. Lushan were analyzed with BC observations from 2018 to 2020, together with meteorological variables, air pollutant data and backward trajectory model. The results showed that the average BC concentration in Mt. Lushan displayed a decreasing trend in the study period, with an annual average BC concentration of (0.606 ± 0.474) μg/m3 for the three years, but the background BC concentration increased by about 0.035μg/m3 per year. For the monthly variation of BC concentration, its minimum value occurred in July [(0.455 ± 0.184)μg/m3] and the maximum value occurred in January [(0.742 ± 0.603)μg/m3]. The diurnal variation of BC concentrations showed a unimodal distribution with maximum values in the midday and afternoon, and the BC concentrations were higher on weekends than on weekdays in all seasons, our findings at Mt. Lushan were in contrast to the results in urban areas. The BC/PM2.5 ratio decreased with increasing PM2.5 concentrations (5.2% to 2.4%) during the observation period, and the average ratio was 3.4%. The correlation coefficients of BC with SO2 and NO2 were 0.27 and 0.26, respectively, but no significant correlation was found between BC and CO, indicating that the local source emissions in Mt. Lushan had ignorable influence and BC were mainly related to meteorological processes such as regional transport or downhill vertical transport. The results of backward trajectory and PSCF indicated that the BC source of Mt. Lushan varied from season to season. In winter and spring, Mt. Lushan was mainly influenced by the air mass from northwest China and North China, and the BC potential source regions were primarily from Shaanxi, Henan, Hubei and Yangtze River Delta (YRD). The air mass in autumn was mostly from the YRD and North China, while the air mass was mainly from the southeast coast in summer, and the corresponding potential source contribution region of BC was similarly distributed.
2023 Vol. 43 (9): 4512-4524 [Abstract] ( 234 ) [HTML 1KB] [ PDF 4476KB] ( 1594 )
4525 Characteristics and sources of atmospheric VOCs pollution in Jincheng
ZHANG Peng-hui, HU Dong-mei, PENG Lin, NIU Wei-li, GONG Xing-xiao, YAN Yu-long, NIU Yue-yuan, DONG Jia-qi
Volatile organic compounds (VOCs) samples were collected at environmental sampling sites in Jincheng, and the characteristics of VOCs components under different wind direction were analyzed. The VOC sources were identified by diagnostic ratios and positive matrix factorization (PMF), the hybrid single-particle lagrangian integrated trajectory (HYSPLIT) was used to trace the contribute of typical contaminated areas in summer. The results showed that the average VOC concentration was (19.4 ±7.1) μg/m3 under southerly wind, and (33.3±17.3) μg/m3 under northerly wind. VOCs concentration in northerly wind was nearly 70% higher than that in southerly wind, and northern industrial park had a great impact on VOCs concentration in urban areas. The components concentration showed the characteristics of alkane > aromatic > alkene >alkyne. The concentration of alkane and aromatic was significantly higher in the northerly wind than that in the southerly wind, and the concentration of alkyne was similar in different wind directions. The average concentration of ozone formation potential (OFP) was (50.5±17.1) μg/m3 under southerly wind, and (84.30±44.0) μg/m3 under northerly wind. Under different wind direction, the contribution of components showed the characteristics of alkene > alkanes > aromatics > alkynes. The hourly variation range of VOCs components and OFP under the north wind direction was significantly higher than that under the south wind direction, especially in the morning and evening and during the rush hour. The northern industrial park and the vehicular emissions had a prominent impact on the urban area. Atmospheric VOCs were controlled by aging air mass under northerly and southerly winds, and the changes of OFP and O3 concentration showed the opposite trends under different wind directions. There was a strong potential source area in the northern border region of Henan, and its percentage contribution to Jincheng summer VOCs was about 25.3%. Local combustion, vehicular emissions and industrial process were the key sources of VOCs control in Jincheng, especially to strengthen the control of industrial and vehicular emissions in the northern region of Jincheng City.
2023 Vol. 43 (9): 4525-4533 [Abstract] ( 176 ) [HTML 1KB] [ PDF 1620KB] ( 2038 )
4534 An investigation of the causes of different adsorption properties of carbon disulfide vapor in gas on polymeric resin and activated carbon
QU Hong-chang, MA Jia-kai, LONG Chao
The reasons for the variations in adsorption performance were investigated as they related to the effects of water vapor and hydrogen sulfide on the adsorption of carbon disulfide onto activated carbon and polymeric resin in a fixed bed column. The findings demonstrated that water, whether co-adsorbed or pre-adsorbed, had a much greater influence on the adsorption of carbon disulfide onto activated carbon than it did onto polymeric resin. This was primarily due to the fact that activated carbon had more oxygen-containing groups (hydroxy and carbonyl groups) with strong affinity for water molecules, which led to the water molecules occupying the adsorption sites. Pre-adsorbed hydrogen sulfide dramatically reduced the ability of carbon disulfide to adsorb onto activated carbon while having no impact on polymeric resin. The results of X-ray photoelectron spectroscopy (XPS) and pore structure analysis demonstrated that hydrogen sulfide reacted on the surface of activated carbon to produce by-products like elemental sulfur, resulting in a reduction of specific surface area and total pore volume by 59.6% and 57.3%, respectively. In addition, inverse gas chromatography was used to evaluate the dispersive components of the surface free energy of the two adsorbents. Higher surface free energy dispersive components were present in activated carbon. The dispersive components of surface free energy can be used to more effectively explain why activated carbon is better at adsorbing a single component of carbon disulfide than W-8resin when compared to pore structure parameters like specific surface area.
2023 Vol. 43 (9): 4534-4541 [Abstract] ( 254 ) [HTML 1KB] [ PDF 1002KB] ( 1942 )
4542 Effect of relative humidities on heterogeneous reaction of SO2/NH3 on the surface of α-Fe2O3
WANG Shuang-xi, HE Xiang, WU Jian-jun
Heterogeneous reactions of SO2/NH3 on the surface of α-Fe2O3 particles were investigated by in situ diffuse reflection Fourier transform spectroscopy. The effect of relative humidities (RHs) on the formation of sulfate particles under the action of NH3 were studied. The results show that sulfate (1271, 1244, 1163, 1069cm-1) and ammonium salt (1698, 1435cm-1) were formed on the surface of particulate matter under dry conditions. NH3 can cooperate with SO2 to promote the formation of sulfate particles. Sulfate peak (1244cm-1) was redshifted to bisulfate (1239cm-1), which implies the formation of bisulfate under wet conditions. As RH increased from 0% to 78%, the formation rate of sulfate decreased from 9.38×10-17 ions/(g×s) to 4.33×10-17 ions/(g×s) on particle surface. Moreover, the uptake coefficient (γ) of SO2 decreased from 2.04×10-6 to 9.43×10-7. These indicated that the water vapors inhibited heterogenous reaction of SO2/NH3 with α-Fe2O3 particles.
2023 Vol. 43 (9): 4542-4549 [Abstract] ( 162 ) [HTML 1KB] [ PDF 662KB] ( 1237 )
4550 Preparation of nitrogen-doped petroleum coke based activated carbon and its performance in catalytic oxidation of hydrogen sulfide at room temperature
ZHENG Hao-ming, ZHU Wen-fu, LUO Ying-hong, WANG Zi-kun, LIU Mei-yin, HUANG Hao-min, YE Dai-qi, LI Hong-xiang, WU Jun-liang
A novel nitrogen-doped porous carbon was successfully prepared using petroleum coke as the carbon source and the solid waste from melamine production as the nitrogen source. The catalyst exhibited excellent H2S catalytic oxidation capacity in room temperature with a breakthrough sulfur capacity of 398.4mg/g. Three process parameters, namely, the amount of activator, nitrogen doping temperature and nitrogen source, changed the specific surface, N configuration and N content of the catalysts, respectively, during the preparation process. By optimizing the process conditions, the highest reactive center, pyridine N, could be achieved at 2.88at.%. Compared with the catalyst prepared using traditional raw material, it achieves waste utilization and green preparation. The results of this paper provide a new approach for the preparation of porous carbon materials with low cost and high breakthrough sulfur capacity.
2023 Vol. 43 (9): 4550-4560 [Abstract] ( 185 ) [HTML 1KB] [ PDF 2529KB] ( 1174 )
4561 Inactivation of Aspergillus niger in liquid desiccant solution enhanced by non-contact ultrasound
ZHAO Zi-heng, YANG Zi-li, GU Yu-qian, MA Ming, WANG Xin-yi, YAN Hong-xu, LIU Feng
This paper introduced the non-contact ultrasound in desiccant solution air-conditioning systems to improve the inactivation effect of liquid desiccant on airborne mold spores. A. niger spores, commonly detected in the air conditioning system, were adopted as mold samples. Experiments were performed with typical liquid desiccant (LiCl solution) under different ultrasound operating modes, i.e., non-ultrasound, non-contact ultrasound, and contacting ultrasound. Various ultrasound and LiCl conditions were also designed to clarify the improvement effects on the inactivation performance. The microbes’ viability was assessed by the methods of microbial culture and SEM observation. The results showed that non-contact ultrasound significantly enhanced the sterilization rate of mold spores in LiCl solution; the reinforced sterilization increased with exposure time to the LiCl solution and the solution’s concentration. Furthermore, the inactivation improvement was not affected the acting distance of the non-contact ultrasound to the liquid desiccant. To realize an optimal inactivation efficiency (80.8% in this paper) and avoid the possible solution crystallization, it was recommended that the liquid desiccant air-conditioning systems apply the 36% LiCl solution with non-contact ultrasound operated at a distance of 20cm for 30s. The underlying mechanism of the inactivation improvement was attributed to the increased permeability of the mold cell membranes by the ultrasonic cavitation effect that allows more ions (Li+and Cl-) to enter the cells. Compared to contacting ultrasound, non-contact ultrasound showed the advantages of not changing the liquid temperature and low power consumption (90±5W), which was 16.07% of the contact ultrasound. The results may provide a new way to improve airborne mold sterilization in liquid desiccant air-conditioning systems.
2023 Vol. 43 (9): 4561-4567 [Abstract] ( 176 ) [HTML 1KB] [ PDF 1857KB] ( 1766 )
Water Pollution Control
4568 Construction and efficiency analysis of reverse photocatalytic oxidation system: a novel pattern to overcome bottleneck of light attenuation
ZHANG Xun-zhi, LU Jin-suo, ZHANG Zhi-qiang, YANG Jing, PANG He-liang
The traditional photocatalytic oxidation technology was greatly limited by water translucency and light energy attenuation. In this study, a high transmittance TiO2film was prepared by liquid phase deposition method, and an innovative reverse photocatalytic oxidation system was constructed. The Rhodamine B (RhB) was employed as the targeted pollutant, and the degrading speed was used to evaluate the performance of reverse photocatalytic oxidation system. The effects of film preparation parameters and mass transfer efficiency on degradation were explored, while the comparisons between forward and reverse photocatalytic systems were expounded. Moreover, the major contributors for RhB degradation and the stability of TiO2film were clarified. It was demonstrated that the RhB degradation process in reverse photocatalytic system obeyed pseudo-first-order kinetics. The TiO2film with the optimum photocatalytic performance was obtained at the following parameters: deposition temperature at 60 ℃ for 1.5h, heat treatment at 700℃ for 1h. The reverse photocatalytic system produced numerous active species (e.g. ·OH), which dominantly contributed to pollutant degradation. The traditional forward photocatalytic system presented significant degrading performance with thin transparent liquid layer, while the reverse photocatalytic system displayed satisfactory degrading performance with the thick transparent liquid layer. Additionally, stable photocatalytic performances were observed in the reverse photocatalytic system in the case of TiO2reuse. The proposed reverse photocatalytic system has potential research and application values in the field of water treatment with poor light transmittance.
2023 Vol. 43 (9): 4568-4577 [Abstract] ( 138 ) [HTML 1KB] [ PDF 963KB] ( 1208 )
4578 The remediation and clogging performance of chlorinated hydrocarbons treated by biochar-iron permeable reactive barrier
CHEN Rui-xin, JIANG Mei-yang, WANG Fei
Column tests were used to study the permeability, clogging and remediation performance of PRB in treating chlorinated hydrocarbon-contaminated groundwater (at different time points within 24hours). The results show that the permeability of carbon iron composite increased with time in 24hours. The removal rate of these PRB columns was the highest at 74.23% after 4hs of operation. The removal rate of which decreases to 64.59% after 8hs’ operation. The removal rate of PRB reactive materials in remediating trichloro ethylene was affected by multiple factors. When the permeability of PRB is low, the water flow rate through which is low as well. Under this condition, hydroxide ions are formed in these PRB system. Hence, ions in the groundwater are precipitated stably and completely, which leads to the clogging of the PRB system. When the water flow is fast, although there are hydroxide ions generated all the time, flushing leads to a higher permeability of the PRB system.
2023 Vol. 43 (9): 4578-4584 [Abstract] ( 183 ) [HTML 1KB] [ PDF 434KB] ( 1330 )
4585 Effect of CO3-• on the degradation kinetics of sulfapyridine in UV/PMS system
ZHOU Die, LIU Hua-ying, WANG Nian, ZHANG Tan, TU Yi-na, LI Ying-jie
Take sulfapyridine (SPD), which is detected frequently in sewage, as the target compound to explore the effect of HCO3- on the degradation of SPD in the UV/PMS system, and discussed the effects of HCO3- concentration, pH, SPD concentration and dissolved organic matter (DOM) on the degradation of SPD in detail. By constructing a free radical kinetic model, the influence and contributions of CO3-• on the degradation of SPD under different environmental conditions were explored. It was found that the addition of NaHCO3 promoted the degradation of SPD, and the apparent degradation rate constant (k) doubled; and with the initial pH value of the solution increasing (5~8), the k value of SPD increased by about 3times; and with the initial concentration of SPD (5~25μmol/L) and the increase of HA (0~20mg C/L), so k value decreased by about 81% and 84% respectively. The constructed free radical kinetic model could better predict the rate constant of UV/PMSoxidative degradation of SPD in different water substrates, with an error range of 0.44%~5.53%. The model showed that CO3-• played an important role in the UV/PMSoxidative degradation of SPD, and its contribution gradually increased with the increase of HCO3-concentration and pH, upped to 34%. With the increase of the initial concentration of SPD and the concentration of HA, their contributions gradually decreased from 34% to 9% and 17% respectively.
2023 Vol. 43 (9): 4585-4595 [Abstract] ( 210 ) [HTML 1KB] [ PDF 1308KB] ( 1424 )
4596 Adsorption mechanism of methyl orange by using the magnetic biochar -Based on density functional theory and batch adsorption experiment study
WANG Shi-sheng, ZHANG Meng-meng, SHENG Guang-hong, TIAN Yong-pan, LIU Yi-yun, ZHANG Hui-juan, LIU Yong-xin
Magnetic biochar (Fe3O4@C-NH2) was used as the adsorbent for removal of Methyl Orange (MO) in this study. The effects of concentration, temperature and pH on the adsorption performance were investigated, and then the Spectroscopic analysis and density functional theory were used to reveal the adsorption mechanism. The results demonstrated that the adsorption kinetics followed the pseudo-second-order model and the Freundlich model, and the process owned the characteristics of spontaneity, endothermic and entropy increasing. The equilibrium adsorption capacity decreased with the increment of pH (3~10). Spectroscopic analysis showed that the adsorption forces contain the hydrogen bonding, π-π bond accumulation, π-π electron donor-acceptor (EDA) and electrostatic interaction. According to the analysis of electrostatic potential and frontier orbit, the binding energy and energy gap of carboxyl group were Eads = -139.08kJ/mol, Egap = 3.07eV respectively, which were higher than those of hydroxyl group (Eads = -94.47kJ/mol, Egap = 3.16eV), amino group (Eads = -76.10kJ/mol, Egap = 3.17eV) and aromatic ring (Eads = -41.99kJ/mol, Egap = 3.18eV). It was found that the hydrophobic action existed in the adsorption process; besides, the hydrogen bond and π-π EDA were the main forces in the process based on the results integrating the independent gradient model and Hirshfeld partition and Atoms in molecules (IGMH-AIM).
2023 Vol. 43 (9): 4596-4605 [Abstract] ( 196 ) [HTML 1KB] [ PDF 2406KB] ( 1996 )
4606 Preparation of silver-based photocatalyst W-Ag3PO4 and its visible light degradation of antibiotic levofloxacin
PANG Zu-zu, DING Ning, LIU Hong
Silver phosphates with different tungsten doping ratios were successfully synthesized by a facile chemical precipitation method, and their degradation effects on levofloxacin were investigated. The morphology, structure and optical properties of the photocatalytic materials were characterized by X-ray diffraction, Fourier infrared spectroscopy, scanning electron microscopy, X-ray energy spectroscopy and UV-vis diffuse reflectance spectroscopy. W6+ enters the silver phosphate lattice, occupies the position of P5+ and enhances the crystallinity of the material. The particle size of tungsten-doped silver phosphate was reduced, the crystallinity was enhanced, and the light absorption range was increased, which further promoted the separation of photogenerated electron-hole pairs. The results of photocatalytic degradation experiments showed that W-Ag3PO4 with 0.5% tungsten content degraded levofloxacin by up to 89% after 90min of light exposure at pH 5. Further analysis of the degradation mechanism revealed that h+ was the major oxide in the photocatalytic process, while ·OH and ·O2- played only a subordinate role. Under visible light irradiation, the modified W-Ag3PO4 exhibited higher catalytic effect on levofloxacin compared with Ag3PO4 alone. The modified silver-based photocatalyst prepared in this study enhanced the photocorrosion resistance of silver phosphate and improved its stability, providing a new route for the efficient degradation of levofloxacin.
2023 Vol. 43 (9): 4606-4615 [Abstract] ( 222 ) [HTML 1KB] [ PDF 2530KB] ( 1735 )
4616 The way of coupling intermittent aeration strategy to inhibit NOB activity in mainstream environment and the dynamic response of microorganisms
XIE Yi-yi, LI Xiang, YUAN Yi, XU Pei-ling, HUANG Yong, WU Peng
The key conditions and inhibition mechanism in nitrification process were analysed by using different sludge sources and anoxic/aerobic ratios of intermittent aeration process under mainstream conditions. The results showed that nitrite accumulation was difficult to obtain in partial nitrification system relying only under low-dissolve oxygen (DO) and intermittent aeration. When coupled with anammox process, NO3--N concentration in effluent decreased from 41.64mg/L to 11.54mg/L under the same NH4+-N conversion environment, and the nitrification process was significantly inhibited. The quantitative analysis shows that Nitrate-oxidizing bacteria (NOB) had strong adaptability in the environment of low-DO and intermittent aeration, with a maximum increase of 2.9 times after 15days of operation, while in a mixed system with anammox bacteria, the maximum increase was only 1.4 times. The results of microbial community structure change showed that in low DO coupled intermittent aeration environment, the abundance of NOB inoculated in mixed sludge system increased faster than that in nitrification sludge system. Therefore, strengthening nitrite utilization and reducing its exposure concentration in aerobic stage is a key condition for achieving NOB inhibition in intermittent aeration process.
2023 Vol. 43 (9): 4616-4625 [Abstract] ( 180 ) [HTML 1KB] [ PDF 1144KB] ( 2005 )
4626 Solubility of in situ SDS microemulsion on chlorinated hydrocarbon mixed pollutants in an aquifer
HAN Yu-jiao, ZHANG Wei hong, DONG Jun, MO Yan-yang, LIANG Xue
In order to prepare an in situ microemulsion suitable for the efficient solubilization of a variety of chlorinated hydrocarbon mixed pollutants in aquifers, this study used a mixture of chlorinated hydrocarbons such as PCE, CT, TCE and CF as the organic phase, and selected a mixture of sodium dodecyl sulfate (SDS), n-butanol and potassium chloride (KCl) as the precursor solution of microemulsion to construct an in situ microemulsion system. The effect of layer temperature and inorganic salt composition on the solubilization effect of in situ microemulsion was evaluated. The experimental results show that there is a quadratic function relationship between the concentration of n-butanol in microemulsion and the equivalent alkyl carbon number (EACN) of mixed chlorinated hydrocarbons, which can be used to determine the formulation parameters of the precursor liquid of microemulsion in the contaminated site of mixed chlorinated hydrocarbons. The solubility of chlorinated hydrocarbons in microemulsion can reach more than 500g/L,and the solubilization capacity is PCE>CT>TCE>CF. The viscosity of the precursor fluid was less than 2cp, and it had good migration performance in the underground environment. zeta potential was negative, which means it is not easy to be absorbed by a negatively charged medium. Temperature (10~20°C) has little effect on the solubilization of chlorinated hydrocarbons in microemulsion. The low concentration of chemical composition in water favored the dissolution of chlorinated hydrocarbons in microemulsion, and the order of influence of inorganic salt cations is Ca2+>Mg2+>K+>Na+.
2023 Vol. 43 (9): 4626-4631 [Abstract] ( 148 ) [HTML 1KB] [ PDF 839KB] ( 1562 )
4632 The abiotic natural attenuation of 1,2-dibromoethane mediated by FeS
GU Chun-yun, LIAO Gao-ming, DENG Yi-rong, MA Jie
The reduction degradation of 1,2-dibromoethane (EDB) by FeS in anaerobic environment was studied. The experimental data showed that FeS could effectively degrade EDB under anaerobic conditions. The degradation reaction conformed to the pseudo-first-order reaction kinetics. The corrected kobs value was (0.065±0.003) d-1 (R2=0.91). The degradation half-life was 11days. FeS were characterized by BET, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope-energy spectroscopy (SEM-EDS). The results showed that FeS had a large specific surface area, which increased the number of reaction sites and thus enhanced the reduction degradation of EDB by FeS. In addition, FeS transformed to goethite and greigite during the reduction reaction. The degradation rate of EDB increased with increases in concentrations of sulfide (HS-) and FeS. At high pH, the reduction degradation of EDB by FeS was faster. In addition, the presence of transition metal ions Co2+ and Cu2+ could promote the degradation of EDB by FeS, while the presence of Mn2+ could inhibit the degradation of EDB. In general, the presence of FeS in the ground can achieve abiotic natural attenuation of EDB in EDB-contaminated groundwater sites.
2023 Vol. 43 (9): 4632-4638 [Abstract] ( 178 ) [HTML 1KB] [ PDF 1142KB] ( 1050 )
4639 Study on heat transfer and aniline remediation effect of thermal enhanced circulation well
LU Liang, PU Sheng-yan, LI Bo-wen
In-situ thermal remediation technology was adopted to enhance the remediation effect of circulation well on semi-volatile organic pollutants in this study. The effects of aeration flow rate, heating temperature and groundwater velocity on the heat transfer law of thermal enhanced circulation well were primarily investigated. Additionally, the remediation effect of aniline contaminated groundwater by thermal enhanced circulation well was simulated. The results revealed that the heat transfer law mainly depends on the hydraulic stimulation of the circulation well. The variation of the heating area with time can be accurately represented by an exponential function. In the medium sand aquifer, when the aeration flow rate was 0.3m3/h, the temperature was 60℃, and the groundwater flow rate was 0.2m/d, the heat transfer has the best operation effect. In the process of enhanced remediation of aniline contaminated groundwater, an efficient remediation area centered on the circulating well was gradually formed. After 48h of remediation, the average concentration of aniline decreased from 97.95mg/L to 0.168mg/L. In compared with the single circulating well technology, remediation effect has been improved 25.8% by integrated remediation technology, effectively avoiding the occurrence of tailing phenomena.
2023 Vol. 43 (9): 4639-4647 [Abstract] ( 226 ) [HTML 1KB] [ PDF 1414KB] ( 1523 )
4648 effects of pH control methods on anaerobic fermentation of waste activated sludge
BI Hao-hua, GAO Chun-di, LIU Yi-wei, XING Yi-yan, PENG Yong-zhen
This experiment focuses on the wasted sludge from municipal sewage treatment plants. Batch texts were taken to explore the effects of different pH regulation methods, which include constant pH adjustment with values of 5,7,9,10 and phased pH adjustment, on the dissolution of organic matter in anaerobic fermentation. The variations of microbial community structure of fermentation sludge under different pH adjustment conditions were analyzed by High-throughput sequencing technology. Results showed that more organic matter could be dissolved under both alkaline and acidic conditions with constant pH adjustment, and the accumulation reached the maximum when pH value was 10. At this point, solluted chemical oxigen demand (SCOD) concentration was 323.77mg/gVSS, and the VFAs was 183.38mgCOD/gVSS. In the case of phased pH adjustment, a constant pH of 10was controlled only in the initial stage of fermentation (the first 4days) and the pH value was naturally reduced in the later stage, this method showed more conducive to the production of VFAs in the acid production stage. This maximum yield was 208.78mgCOD/gVSS, which was 13.90% higher than the maximum total VFAs of same pH value but with constant pH adjustment. At the phylum level, significant differences in microbial abundance appeared after different pH adjustment operations , but the main dominant microorganisms were still Firmicutes, Proteobacteria, Actinobacteriota and Chloroflexi. Under constant pH regulation, the relative abundance of Firmicutes and Actinobacteriota reached 61.14% and 15.57% when pH value was 10, which was the highest beyond other pH values. As for the phased pH regulation, the relative abundance of Firmicutes and Actinobacteriota increased to 68.46% and 18.43% respectively , which grew more proportion than the condition of constant pH adjustment mentioned above. At the genus level, the bacterial abundance related to hydrolytic acidification (Proteiniclasticum, Bacillus, Acetoanaerobium, Proteocatella and Alkaliphilus, etc.) accounted for 32.38% when pH value was constantly 10, and 51.62% under phased regulation. The phased pH regulation improved the relative abundance of hydrolytic acidifying bacteria and was more contributive to the accumulation of VFAs during fermentation.
2023 Vol. 43 (9): 4648-4657 [Abstract] ( 333 ) [HTML 1KB] [ PDF 1382KB] ( 1890 )
4658 Effect of inoculated sludge and pH on the anaerobic degradation of sodium carboxymethyl cellulose as well as microbial community analysis
BAN Qiao-ying, ZHANG Si-yu, WANG Yang, ZHANG Li-guo, YAN Rui-feng
In order to reveal the anaerobic degradation efficiency of sodium carboxymethyl cellulose (CMC-Na), the effects of different types of inoculation sludge and initial pH on the anaerobic degradation of CMC-Na were investigated by batch culture. The response of microbial community on initial pH was revealed by Illumina MiSeq sequencing. The results showed that the flocculent sludge had strong hydrolysis and fermentation acid-producing capacity under the initial CMC-Na concentration of 5g/L condition. However, this system was unfavorable for syntrophic acetogenesis and methanogenesis, resulting in the methane yield was reached 10.0mL/g CMC-Na. On the contrary, the high methane fermentation capacity of the granular sludge made the methane yield reached 100.2mL/g CMC-Na. The effects of initial pH on anaerobic degradation of CMC-Na showed that the methane production was significantly inhibited by initial pH 4.5 and 9.5. However, the methane yield reached the maximum (123.4 and 123.2mL/g CMC-Na) at the initial pH 7.5 and 8.5. Illumina MiSeq sequencing showed that the microbial composition in different initial pH conditions was significantly different. At initial pH 7.5, Metanothrix and Metanobacterium were the dominant methanogens, while Macellibacteroides, Petromonas, Trichococcus, Anaerofilum and Brooklawnia were the dominant fermentation acid-producing bacteria. When the initial pH was 4.5 or 9.5, Metanosarcina also became a dominant genus, and the relative abundance of the main fermentation acid-producing bacteria was changed significantly.
2023 Vol. 43 (9): 4658-4665 [Abstract] ( 194 ) [HTML 1KB] [ PDF 668KB] ( 1909 )
4666 Characteristics of extracellular polymer substances and signal molecule function in autotrophic nitrifying granular sludge
CHEN Ning, LIU Chong, LI Yu-guang, ZHANG Xin, SHEN Fei, WANG Shuo, LI Ji
Autotrophic nitrifying granular sludge (ANGS) was cultivated using activated sludge as the inoculated sludge in SBR. The cultivation of autotrophic nitrifying granular sludge was relatively long and the control of granulation process was difficult, however, ANGS with good sedimentation property can be obtained, and ammonia nitrogen removal was higher than 90%. TB-EPS had the highest proportion of protein and polysaccharide, and the respective content of TB-PN and TB-PS were 90.69mg/gVSS and 53.69mg/gVSS on the 70th day. As the core of sludge particle structure, TB-EPS played an important role in the granulation process. Hydrophobic tryptophan and tyrosine are beneficial to the SMP layer and LB-EPS to enhance the adhesion between the sludge, thereby promoting the formation of autotrophic nitrifying granular sludge. The relative proportion of 8hydrophobic amino acids increased from the initial 34% to the highest 66%, indicating that hydrophobic amino acids play an important role in the critical period of granulation process. Polymerase chain can enhance the binding force between sludge particles, and β- folding structure was able to provide more hydrophobic sites to promote the accumulation of the sludge particles, which was favorable to the formation of ANGS. The concentration of C4-HSL reached 112.00ng/L, and it could combine with LuxR protein to promote protease activity and EPS production. C6-HSL and C8-HSL could regulate the biofilm formation of nitrification bacteria. C6-HSL was up to 30μg/L on the 30th day, and its content was the highest, indicating that it plays an important role in the signal transmission of autotrophic nitrification granular sludge. 3OC6-HSL was positively correlated with protein substances, and its correlation coefficients with SMP-PN and LB-PN were 0.77 and 0.71, which may enhance the adhesion of sludge by guiding the synthesis of protein substances, thus facilitate the aggregation of sludge particles.
2023 Vol. 43 (9): 4666-4675 [Abstract] ( 186 ) [HTML 1KB] [ PDF 1635KB] ( 2144 )
4676 Study on the performance of AnMBR in treating the co-digestion of sewage sludge and food waste
CHENG Dong-xing, HU Yi-song, QU-Yi, LIU-Le, WANG Jia-shun
A high-solid anaerobic membrane bioreactor (AnMBR) process was developed to investigate the effects of organic loading rate (OLR) on the treatment of excess sludge and food waste. When the OLR was 4gCOD/(L·d), the methane yield reached (301.5±4.2) mLCH4/gCODfed, which was related to the high hydrolysis rate (78.8%) and specific methanogenic activity. When the OLR was 4~8gCOD/(L·d), a long-term stable operation at a low membrane fouling rate (0.3kPa/d) was achieved by adjusting the effluent pump operating mode. After physical and chemical cleaning, SEM-EDX analysis showed that the fouled membrane could be restored to the original form, and the contents of C, Fe, P and other elements were significantly reduced. Metagenomics sequencing showed that Defluviitoga was the dominant genus of bacteria when the OLR was 4gCOD/(L·d). Methanosarcina was the dominant archaea (76.9%). When the OLR increased to 8gCOD/(L·d), the relative abundance of Methanothrix improved significantly to 50.4% being the dominant archaea at this stage, and the archaea community was greatly affected by OLR variations. Under high OLR conditions (such as 11g COD/(L·d)), the relative abundance of Methanoculleus increased gradually (0.7% to 2.4%). The results of macrogene sequencing showed that the inhibition of hydrogen-trophic methanogenesis activity under high load may be related to the changes in the proportion of metabolic pathways of K14126(mvhA), K00205 (fwdF, fmd) and K00125(fdhB). Selecting appropriate OLRs is conducive to establishing stable microbial community and efficient anaerobic co-digestion metabolic pathway, which promotes the bioconversion of organic wastes to methane.
2023 Vol. 43 (9): 4676-4687 [Abstract] ( 154 ) [HTML 1KB] [ PDF 2099KB] ( 1625 )
4688 Formation process and microscopic characteristics of autotrophic nitrifying granular sludge
LIU Chong, LI Yu-guang, CHEN Ning, ZHANG Xin, SHEN Fei, WANG Shuo, LI Ji
In this study, mature aerobic granular sludge and flocculation activated sludge were both used as inoculation sludge in sequencing batch reactor (SBR) to rapidly culture ANGS. The experimental results showed that the addition of mature aerobic granular sludge is conducive to the rapid formation of ANGS and quick start-up of SBR. Aerobic granular sludge can provide the attachment carrier for nitrifying bacteria, and rapidly cultivate ANGS with good ammonia nitrogen removal performance. Extracellular polymeric substances (EPS) plays an important role in the formation process of ANGS, and tightly bound-EPS (TB-EPS) had the highest protein and polysaccharide contents, they reached 192.197 and 59.380mg/g vss, indicating that the microbial communication was intensive TB-EPS layer, and TB-EPS is beneficial to the formation of ANGS. Hydrophobic tryptophan and tyrosine up to 70% can provide more hydrophobic adsorption sites for soluble microbial products-EPS (SMP-EPS) and loosely bound-EPS (LB-EPS), thereby enhancing the adhesion of the sludge particles and promoting the formation of ANGS. In addition, the increased proportion of humic acid and soluble microbial metabolites in TB-EPS are beneficial to enhance the flocculation ability of ANGS. Glutamic acid, as the crossing point between carbon and nitrogen metabolism, accounts for 11.18% to 13.64%, is the basic amino acid of nitrogen metabolism, and the increase of proline content is helpful to maintain the stability of biofilm structure. The favorable aggregation structures including a-helix, b-angle and reverse b-folding of protein secondary structures in the amide Ⅰ region were much higher than the unfavorable aggregation structures, indicating that the stability of ANGS was enhanced during the granulation process.
2023 Vol. 43 (9): 4688-4696 [Abstract] ( 236 ) [HTML 1KB] [ PDF 1340KB] ( 1552 )
4697 Effects of the increased solid content of waste activated sludge on syntrophic acetate oxidation for methane production through thermophilic anaerobic digestion
ZHU Jun-zhao, ZHUO Yang, HUA Fei-hu, ZHOU Meng-yu, WANG Xue-na, LIU Jin-yang, HAN Yun
This study investigated the kinetic rate variations of each stage involved in anaerobic digestion under different ammonia loadings, in this process, the inoculated sludge was obtained from a thermophilic anaerobic digestion system with solid content of 2%. Furthermore, effects of the quick switch between low solid content (2%) and high solid content (10%) on methane production potentials were explored through feeding thermal hydrolyzed sludge to a continuous flow model. Results showed that with ammonia loading increasing, the specific methanogenic activities of typical substrates like acetic acid, propionic acid, butyric acid, and thermal hydrolyzed sludge were all decreased, while the hydrogen utilization rates (HUR) and syntrophic acetate oxidation (SAO) rates were not significantly affected. With continuous flow model, although the chemical oxygen demand (COD) removal ratio was insufficient (27.99±3.66)% and the VFAs accumulation (10.41±2.25) g COD/L was observed when the organic loading reached 14g COD/(L·d), the pH values remained stable at (7.74±0.09). This result suggested that this switching strategy was feasible in achieving stable operating condition. The predominant hydrogen-producing acetogen and syntrophic acetate oxidizing functional genera were Coprothermobacter (15.29%), Anaerobaculum (8.89%), Tepidimicrobium (17.99%), and Syntrophomonas (1.60%) at stable stage. Moreover, Methanothrix, acetoclastic methanogen, was eliminated, while Methanosarcina and Methanothermobacter, being involved in the syntrophic acetate oxidation process, was significantly enriched. It can be concluded that the above anaerobic digestion system resists the environmental stress of high temperature and ammonia through establishing syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis (SAO-HM) pathway. Overall, using conventional thermophilic anaerobic digestion sludge as the inoculated sludge is an effective strategy to achieve switching from conventional solid content to high solid thermal hydrolysis pretreatment following thermophilic anaerobic digestion (THP-TAD), and the syntrophic acetate oxidation activity of the inoculated sludge is the key factor for this successful switch.
2023 Vol. 43 (9): 4697-4707 [Abstract] ( 139 ) [HTML 1KB] [ PDF 1181KB] ( 1954 )
4708 The improvement of sludge dewaterability by bio-iron/cerium nanoparticles combined with sodium percarbonate
CHEN Yue, GUO Bo, XING Hai-shuang, MENG Jia-qi, CAO Qun
Bio-Fe/Ce-nanoparticles (Fe/Ce-NPs) prepared from grape-peel-seed extracts, Fe2+ and Ce3+salts, were combined with sodium percarbonate (SPC) for activated sludge conditioning. Under the optimum conditions (molar ratio of iron to cerium 4:1, Fe/Ce-NPS dosage 30mg/g·TSS, SPC dosage 200mg/g·TSS, pH3 and 30min reaction), the specific resistance to filtration (SRF), Time to filtration (TTF) and water content of mud cake was reduced from 9.74×1013m/kg, 92s and 80.5% to 2.67×1013m/kg, 42s and 71.2%, respectively. Then, the water content can be further reduced to 65.8% with the combination of polyacrylamide (PAM). When at initial pH 6, the pH value of sludge after conditioning is 7.1 (free from subsequent adjusting pH to neutral), and the conditioned sludge still maintain good dewaterability. During the Fenton-like reaction (Fe/Ce-NPs+SPC), electron transfer between Fe and Ce promoted the production of · OH greatly (0.9 times higher than the traditional Fenton reaction) and reduced the absolute value of Zeta potential drastically (from -17.5mV of raw sludge to -4.6mV after pretreatment). Three-dimensional fluorescence spectrum (3D-EEM) and FTIR characterization showed that Fe/Ce-NPs+SPC oxidation could interrupt the hydrogen bonds maintaining α- Helical and change the conformation of the secondary structure of extracellular protein, causing the looser protein structure, the more bound water in the sludge flocs releasing. Compared with Fenton systems (Fe2+/H2O2) and (Fe2+/SPC), sludge dewaterability could be improved distinctly by Fenton-like system (Fe/Ce-NPs+SPC), especially conditioning sludge at near-neutral pH 6 with great reduction of acid-base dosage. Hence, Fe/Ce-NPs+SPC would be a new eco-friendly, efficient and practical technology for enhancing sludge dewaterability.
2023 Vol. 43 (9): 4708-4717 [Abstract] ( 213 ) [HTML 1KB] [ PDF 1889KB] ( 1828 )
4718 Influence of operation mode on the bacterial-algal symbiotic granular sludge system
LI Dong, CHAI Chen-xu, LI Shuai, ZHANG Fu-dan, ZHANG Jie
A sequencing batch reactor and a continuously stirred tank reactor were used to start the bacterial-algal symbiotic granular sludge system for the investigation into the impact of different operation modes, including the differences in algal content, pollutant removal performance and microorganisms in the two systems. The results showed that the spatial distribution of algae in the bacterial-algal symbiotic granular sludge was different in the two operation modes, and the algae in the SBR system acted the inner layer and the bacteria were mainly distributed in the outer layer, and the granules were more likely to disintegrate when the external environment changed. While the algae in the CSTR system were uniformly distributed throughout the granules, and the filamentous bacteria were able to act as a skeletal network to trap suspended algae and bacteria in the granulation process, which facilitated the enrichment of algae and rapid granulation of sludge. The removal pathway of total inorganic nitrogen differed between the two modes of operation, which was dominated by functional bacteria in the SBR system, while dominated by algae assimilation in the CSTR system due to the inhibition of nitrite oxidizing bacteria with better removal efficiency. The removal rates of chemical oxygen demand, total phosphorus and total inorganic nitrogen in the CSTR system were about 96%, 96% and 60% at the end of the experiment. The microbial communities were different between the two modes of operation, with more algal species and higher abundance in the CSTR system and more functional bacteria in the SBR system.
2023 Vol. 43 (9): 4718-4727 [Abstract] ( 226 ) [HTML 1KB] [ PDF 1073KB] ( 1457 )
4728 Effect of red mud-based biochar carrier on the enrichment of anaerobic ammonia oxidation sludge
QIN Yong-li, WEI Qiao-yan, JIANG Yong-rong, CHEN Rui-hong, LIAO Ji-qing, YAN Jia-qi, WU You
To achieve rapid enrichment of anaerobic ammonia oxidation (Anammox) sludge, the red mud-based biochar carrier was prepared using red mud as the iron source and Erianthus arundinaceus straw as the biochar precursor, and then mixed it with the natural pond sludge treated for aquaculture digestate and dosed into an up-flow anaerobic sludge bed (UASB) reactor. The changes in the nitrogen removal performance, sludge performance and microbial community structure of reactors during the domestication of Anammox sludge were investigated, and the effect mechanism of the red mud-based biochar carriers on Anammox sludge enrichment was evaluated. We found that the Anammox sludge was successfully enriched in R2reactor containing red mud-based biochar carrier after 59days incubation, and the removal rates of NH4+-N and NO2--N were 1.47kg/(m3·d) and 1.91kg/(m3·d), respectively. Whereas the Anammox sludge enrichment was happened in R1reactor without carrier at day 92. Compared with R1 reactor, R2 reactor showed significantly effective in the process of Anammox sludge domestication, including the extracellular polymeric substances (EPS) secretion, sludge particle size and granulation. At the end of domestication, high population of anaerobic ammonia oxidizing bacteria (AnAOB) attached to the pores of red mud-based biochar carrier and accumulated iron surrounding AnAOB were observed in R2reactor, while the AnAOB from R1reactor were relatively small and dispersed. The specific anaerobic ammonia oxidation activity (SAA) of R2 was 2.3 times higher than that of R1, and the Anammox gene copy number from R2 was increased by 3.8times comparison from R1 at the end of domestication. These results suggest that the red mud-based biochar carrier could markedly accelerate the enrichment of Anammox sludge. This carrier not only provides a "house" for AnAOB to resist the unfavorable environment, also plays a role in the metabolism and agglomeration growth of AnAOB which depends on the active components of red mud, iron. Importantly, the red mud-based biochar carrier was made of solid waste, which is economically effective in practical applications.
2023 Vol. 43 (9): 4728-4739 [Abstract] ( 211 ) [HTML 1KB] [ PDF 2192KB] ( 1865 )
Soil Pollution Control
4740 Level of 137Cs in Chinese terrestrial surface soils and plants
ZHAI Shao-jing, ZHANG Xiao-lin, ZHANG Hai-tao, YI Xiao-wei, LIN Jian-feng, ZHANG Wei-chao, ZHANG Jia-mei, ZHANG Zi-lu, DANG Hai-jun
In order to assess the artificial radioactivity level in China, 137Cs contents in soil and plant samples were analysed by anti-Compton HPGe γ spectrometry, with Monte-Carlo method used to correct the detection efficiency for samples with different geometry and density. The analysis results showed that the highest artificial radioactivity of soil samples was observed for Hami region in the northwest with a specific activity of 29.9Bq/kg, followed by the Hanwula region in the northeast with a specific activity of 24.6Bq/kg; The relatively high level zone was a band of about 3000km long and 200km wide from Hami to Hanwula, basically same as the transporting route of the radioactive clouds from the atmospheric nuclear tests in the upwind test sites in the last century. Beyond this band, the 137Cs level of the soil was very low. However, the 137Cs content in all the soil samples lies in the range of the global fallout with the most probable specific activity was 1.74Bq/kg. The 137Cs level in plant samples was very low overall, most of which was lower than 1.5Bq/kg. A few high values were observed for Yunnan, Henan Province, where the exchangeable 137Cs content of soil samples are probably rather high.
2023 Vol. 43 (9): 4740-4749 [Abstract] ( 193 ) [HTML 1KB] [ PDF 2301KB] ( 1657 )
4750 Characteristics and mechanism of nitrate on adsorption of monothioarsenate in soil
SHI Qian, SHAN Hui-mei, LIU Ji-gang, LI Zhe-ying, ZHANG Jin-xian
In this study, batch experiments were carried out to investigate the effects of NO3- (0~50mg/L) addition on monothioarsenate (MTA) adsorption by natural soil. Characterization analysis of XRD, SEM-EDS, XPS, etc. was conducted to further identify the mechanisms. Results showed that: (1) the equilibrium adsorption capacity of MTA on soil (Qe) gradually increased with the increase of NO3- concentrations. Specifically, when the NO3- concentration increased from 0to 50mg/L, Qe increased from 27.73mg/kg to 32.95mg/kg,respectively. Besides, SEM-EDS results showed that after the reaction, the As content of the soil increased slightly with the increasing concentrations of NO3- in the reaction system. These findings indicated that the presence of NO3- can promote the adsorption of MTA on soil, and higher concentrations of NO3- lead to more MTA adsorbed by soil. (2) After MTA adsorption, the NO3- content in the solution decreased to various degrees and NH4+ was detected in the MTA-soil-NO3- system, meanwhile aluminum oxides and iron oxides containing arsenic and nitrogen were formed on the surface of soil. This was attributed to the fact that MTA was mainly adsorbed by iron and aluminum oxides in soil. When NO3- was present in the reaction system, accompanied by NO3- partially reduction to NH4+, Fe(II) was oxidized to Fe(III) (hydrogen) oxide on the soil surface, which helped improve the MTA adsorption.
2023 Vol. 43 (9): 4750-4759 [Abstract] ( 217 ) [HTML 1KB] [ PDF 1337KB] ( 1329 )
4760 Empirical analysis of soil and groundwater remediation in contaminated sites in Tianjin
MENG Hao, MEI Dan-bing, DENG Jing-fei, LIU Peng, DONG Jing-qi, XIAO Meng, ZHANG Hong-zhen, LI Xiang-lan
This study selected Tianjin as the research area and revealed the impact of remediation behavior at the regional scale by analyzing remediation characteristics, pollutant fate, technology application, and remediation carbon emissions. During the 7 years from 2015 to 2021, 44 industrial contaminated sites, 8788100m3 of contaminated soil and 20 groundwater contaminated sites, covering an area of 1066400m2, were remediated. In the future, the volume of remediation would keep rising. Organic pollution was the main type of soil remediation, and 40270.48t of 6types of characteristic contaminants were remediated. The remediation technology showed a trend of off-situ transition to in situ, in which in situ chemical oxidation, barriers and pump and treat were the most frequently applied in soil and groundwater remediation, respectively. The total carbon emission and carbon emission intensity in the past 7 years were 1253900t and 0.14t/m3, respectively, and groundwater remediation also depended on high carbon emission remediation technology, and the overall sustainability of remediation need to be strengthened. The calculated results of this study had certain uncertainties, among which the average concentration of pollution factors in soil and carbon emission factors of remediation technology had a great impact on the material flow and carbon emission results. It is suggested to strengthen the assessment system of green sustainable remediation of contaminated soil and groundwater at the regional level, improve the dynamic tracking level of contaminated material flow and management ability, and explore the sustainable risk management system under coastal facies geological conditions.
2023 Vol. 43 (9): 4760-4767 [Abstract] ( 223 ) [HTML 1KB] [ PDF 1280KB] ( 1796 )
4768 Effect of pH and cations on co-transport of ciprofloxacin and soil colloids
LIU Xiao-wen, SHAO Ming-yan, XU Shao-hui, LIN Qing
Soil colloids play an important role in the transport and transformation of antibiotics in underground environments, but the transport forms of antibiotics in dissolved and colloidal states have not been fully studied. The co-transport characteristics of ciprofloxacin (CIP) and brown soil colloids under different pH and cationic conditions were studied by static adsorption and column experiments. The results showed that CIP transport was inhibited by brown soil colloids at pH 4.0. At pH 7.0 and 9.0, soil colloids had no significant effect on CIP transport, but some CIP was transported in the colloidal form. Compared with pH, cations (Na+/Ca2+) had more significant effects on the co-transport of CIP and soil colloids. Except for low NaCl concentration (0.001mol/L), CIP transport was inhibited by large amounts of deposited colloids on the quartz sand. With the increase of ionic strength and cationic valence, the inhibition effect weakened due to the decreased adsorption capacity of CIP on brown soil colloids. Under 0.01mol/L NaCl, CIP was activated with the release of soil colloids as the ionic strength in bulk solution decreased, but this phenomenon did not occur under CaCl2, which can be explained by the DLVO theory and straining effect. In addition, CIP inhibited the transport of brown soil colloids under all tested conditions due to the increased surface charge heterogeneity and aggregation of colloids. Our findings demonstrated that the mobility of soil colloids and their adsorption capacity jointly determined the influence of colloids on CIP transport, and the antibiotic transport form not just the total amount should be carefully considered as assessing the potential environmental risks of antibiotics.
2023 Vol. 43 (9): 4768-4779 [Abstract] ( 167 ) [HTML 1KB] [ PDF 1020KB] ( 1581 )
Environmental Ecology
4780 Spatio-temporal variation of biodiversity maintenance function and its driving factors in the Yellow River Basin from 2000 to 2020
LI Jing, LI Shuai, ZHANG Ying, PANG Jia-cheng
This study constructed a model that incorporates habitat quality, climate, altitude, and habitat type to comprehensively assess the biodiversity maintenance function. The spatio-temporal variation characteristics of biodiversity maintenance function in the Yellow River Basin from 2000 to 2020were analyzed, and the impact factors were detected and analyzed using GeoDetector. The model accurately assessed the biodiversity maintenance function of the Yellow River Basin. The southeast region had a high biodiversity maintenance function, while the northwest region had a low function. The Hengduan Mountains, Qinling Mountains, Ziwuling Mountains, Luliang Mountains, Taihang Mountains, and Taiyi Mountains had high biodiversity maintenance function, while the western desert, the source region of the Yellow River, and the urban construction area had low biodiversity maintenance function. The biodiversity maintenance function of the Yellow River Basin continued to improve from 2000 to 2020, and the proportion of areas with strong or extremely strong biodiversity maintenance function increased by 13.41% in the past 20 years. The biodiversity maintenance function of the Yellow River Basin showed strong spatial autocorrelation and polar aggregation. Habitat quality was the most important factor affecting the spatial variation in biodiversity maintenance function. Annual precipitation and average annual mild habitat type also had significant explanatory power, and human factors gradually increased in explanatory power over the study period. The change in biodiversity maintenance function of the Yellow River Basin from 2000 to 2020 was mainly driven by the change in habitat type and habitat quality, with habitat type being the main reason for the decrease and increase in biodiversity maintenance function. In the future, scientific afforestation, afforestation, and grass planting should be carried out to change the habitat type from low maintenance function to high maintenance function. Additionally, ecological engineering implementation should focus on improving the quality of habitat types.
2023 Vol. 43 (9): 4780-4790 [Abstract] ( 189 ) [HTML 1KB] [ PDF 3267KB] ( 1619 )
4791 Response of phytoplankton to haze addition in various water layers in the Yellow Sea and the Bohai Sea
ZHANG Yan-song, WANG Qin, ZHANG Chao, JIN Hao-yu, GAO Hui-wang
The effects of haze on phytoplankton in different water layers were investigated through ship-based containment culture experiments in the South Yellow Sea and Bohai Sea. Surface seawater (Sur) and Deep Chlorophyll Maximum seawater (DCM) were collected and mixed 1:1 in mixed layer seawater (Mix). Ship-based isolation culture experiments were conducted with haze added to seawater in three water layers. The results showed that haze addition could alleviate N limitation in nutrient-poor seawater and promote the growth of phytoplankton. However, under multi-factor limiting conditions, the responses of phytoplankton to haze addition varied significantly. In the southern part of the South Yellow Sea, the response degree of phytoplankton to haze addition was DCM layer > Mix layer ≈ Sur layer due to the increase of N nutrients with depth. In the northern part of the South Yellow Sea, phytoplankton was affected by Si restriction, especially in the surface layer, and the response degree of phytoplankton to haze addition was DCM layer > Mix layer > Sur layer. In the southern Bohai Sea, phytoplankton was affected by light restriction, especially in the deep layer, and the response degree of phytoplankton to haze addition was Sur layer ≈ Mix layer > deep layer. In addition to promoting the growth of phytoplankton, haze addition can also shift the size structure of phytoplankton from small particle size to large particle size. Specifically, the proportion of microsized phytoplankton decreases, while the proportion of nanosized phytoplankton increases because the addition of haze can increase the N/P in seawater. The overall particle size structure of phytoplankton increased, resulting in the decrease of POC/Chl a value in seawater.
2023 Vol. 43 (9): 4791-4800 [Abstract] ( 203 ) [HTML 1KB] [ PDF 1055KB] ( 1360 )
4801 Effects of nutrient addition on vegetation productivity and community structure stability
YOU Chun-he, GAO Ji-xi, TIAN Mei-rong, LI Han-ting, ZHU San-ning, LI Han-Cong
Taking degraded grassland in Xilin Gol, Inner Mongolia as the research object, this study evaluated grassland productivity and community structural stability by adding nitrogen, phosphorus and potassium nutrients to the experimental plots based on the method of "3414" test design. The effects of compound nutrient on the structure and stability of grassland community varied under different ratios, and that an appropriate nitrogen, phosphorus and potassium ratio, significantly increased grassland biomass, promoted the recovery of dominant vegetation and improved the community stability. The comprehensive evaluation results indicated that the ratio of N 4.19g/m2, P 1.85g/m2and K 1.21g/m2could significantly increase the density, height and aboveground biomass of the dominant species Leymus chinensis(P<0.05), and notably reduce the density and biomass of the degradation indicator species Cleistogenes squarrosa(P<0.05), which means the importance value of the dominant species was increased while that of the degradation indicator species was decreased. Reasonable nutrient regulation pattern can be an important approach to grassland ecological restoration.
2023 Vol. 43 (9): 4801-4809 [Abstract] ( 255 ) [HTML 1KB] [ PDF 1768KB] ( 1559 )
4810 Distribution characteristics of various forms of phosphorus and the traceability of phosphorus in particulate form in Hulun Lake basin
LU Xiao-feng, GUO Yi-nan, WANG Guo-xi, JIANG Xia, WANG Kun
In this paper, we selected 23 sites in the Hulun Lake area to analyze the concentration of different phosphorus forms in the sediments of Hulun Lake and its inlet and outlet rivers. The composite fingerprint identification technology was then used to explore the sources of particulate phosphorus (PP) and the relative contributions of different sources. Results showed that the total phosphorus (TP) concentration in Hulun Lake Basin ranged from 0.04 to 0.33mg/L, with an average of 0.14mg/L. The proportions of PP to TP was 45.79% ~ 92.78%. The main source of PP in Hulun Lake sediments was degraded grassland (34.1%~100.0%), followed by grassland (0%~50.7%) and farmland (0%~15.2%). Degraded grassland was also the main source of PP in the sediments of Urson River (49.4%~57.1%), Xinkai River (artificial river, 100%) and Yinhejihu River (artificial river, 83.6%). Grassland contributed an additional 42.9%~50.6% of PP in the Urson River sediments. This study provides a theoretical basis for the control of phosphorus pollution in the Hulun Lake Basin and the improvement of the lake water environment.
2023 Vol. 43 (9): 4810-4818 [Abstract] ( 195 ) [HTML 1KB] [ PDF 1040KB] ( 2008 )
4819 Spatial distribution and quantitative source identification of heavy metals in sediment cores of Jiaomen Waterway
YANG Chen-chen, WANG Zhuo-wei, LI Rui, TIAN Di, WU Qi-rui, YANG Zai-zhi, LIANG Zuo-bing, GAO Lei, LIAN Jian-bin, CHEN Jian-yao
To explore the spatial distribution characteristics, pollution risks and potential sources of heavy metals in the sediments of Jiaomen Waterway, a tidal reach of the Pearl River estuary, six cores to a depth of 15cm were collected with basic physicochemical properties and geochemical fractions of heavy metals analyzed for all sediment samples of every 1cm. The results showed that the concentrations of heavy metals of Cd, Cr, Zn, Ni, Cu and Pb in sediments were higher than those of the background value in the Pearl River estuary, and conductivity (EC), pH and sediment organic carbon (SOC) were found to be the main factors affecting the spatial distribution pattern of heavy metals. e.g., the concentrations of Cd, Zn, Cu and Pb decreased significantly with the increase of salinity (p<0.05). In addition, the main fraction of of heavy metals changed accordingly with salinity, i.e., the acid soluble fraction of Zn, Ni, Cu and Pb showed a general decreasing trend with the increasing salinity, while an opposite trend was observed for the residual fraction. The pollution level and potential ecological risk of sediment metals generally descended with increase in salinity, and Cd was identified to be the main element inducing ecological risks. Anthropogenic activities were considered the main cause for enrichment of Cd, Cu, Pb, Zn, Fe and Mn in sediments, with agrochemicals recognized as the main source for sediment Cd and Cu, traffic activities for Pb, and industrial activities for Zn, Fe and Mn, while natural weathering of parent minerals were judged as the principal origins of other metals such as Ti, Ni, Cr and Co.
2023 Vol. 43 (9): 4819-4827 [Abstract] ( 186 ) [HTML 1KB] [ PDF 767KB] ( 1530 )
4828 Spatiotemporal variation of water color conditions in the Bohai Sea based on Sentinel-3OLCI data
WANG Lin, WANG Xiang, CHEN Yan-long, GAO Si-wen, ZENG Yi-le, MENG Qing-hui, WANG Xin-xin
The Forel-Ule scale was introduced to record the colors of oceans and inland waters. It classified natural water colors into 21 grades ranging from dark blue to reddish brown. With satellite data, it has been possible to extract the Forel-Ule index (FUI) , which correspond to 21 levels of the Forel-Ule scale. Based on Sentinel-3OLCI satellite data, the monthly and annual FUI of the Bohai Sea for the past five years from 2018 to 2022 was extracted. In addition, spatial and temporal variations in water color conditions were investigated. As can be seen from the results, both the spatial and temporal variation of FUI in the Bohai Sea was significant. High FUI values were observed in the coastal waters of Liaodong Bay, Bohai Bay, and Laizhou Bay. This indicated turbid water and poor water color. In contrast, low FUI values were observed in Qinhuangdao and other offshore waters, reflecting relatively clear water and good water color. A "V" shaped change, i.e., the FUI varied from large to small and then to large, from January to December, in the variation of the monthly FUI average in the Bohai Sea was captured, illustrating the process of the Bohai Sea's water color condition from turbid to clear and then to turbid. An overall decreasing trend in the annual FUI average value was detected, corresponding to the water color condition getting better, from 2018 to 2022. During this period, the highest decreasing rate happened from 2018 to 2019, subject to the Bohai Sea comprehensive management battle. The lowest level was in 2020, followed by a slight rebound in 2021. The annual FUI average value reached its lowest level in 2022. Compared with 2020, the percentage of sea area with improved, stable, and deteriorating water color in 2022 was 36.05%, 50.45%, and 13.50% respectively. This was the best performance in five years. Therefore, it was seen that comprehensive management of the Bohai Sea had played an active role in improving its ecological environment. Monitoring FUI with remote sensing increased the capacity for regular inspections and supervision of China's marine ecological environment. This was of great practical importance.
2023 Vol. 43 (9): 4828-4836 [Abstract] ( 257 ) [HTML 1KB] [ PDF 1370KB] ( 1790 )
4837 The current status and prospects of biodegradation of chlorinated hydrocarbons under micro-aerobic conditions
XING Zhi-lin, SHI Yun-chun, SU Xia, GOU Fang, ZHAO Tian-tao
The biodegradation characteristics of chlorinated hydrocarbons (CAHs) in micro-aerobic environments were summarized in this study. A systematic investigation of CAHs contamination in micro-aerobic environments was conducted, revealing extensive CAHs pollution in locations such as groundwater, soil vadose zones, riverbed sediments, and landfill sites with micro-aerobic conditions. Additionally, the study compiled the pathways of CAHs degradation under oxygen regulation and analyzed the transformation characteristics, microbial activity, and functional gene expression of CAHs in micro-aerobic environments. It was concluded that oxygen had five distinct effects on CAHs degradation under micro-aerobic conditions, with degradation rates often surpassing those observed under strictly aerobic or anaerobic conditions. Moreover, both aerobic and anaerobic degraders coexisted in micro-aerobic environments, as evidenced by the detection of aerobic functional genes (etnC and etnE) and anaerobic functional genes (vcrA and bvcA) in various micro-aerobic pollution sites, indicating that aerobic transformations and anaerobic dechlorination could occur simultaneously in the same spatial and temporal settings. Finally, future development directions were projected in four aspects, including monitoring device development, adaptation mechanisms, transformation mechanisms, and microecological evolution patterns. These results offer valuable insights for the study of pollutant transformation in micro-aerobic environments and the formulation of pollution control strategies.
2023 Vol. 43 (9): 4837-4848 [Abstract] ( 184 ) [HTML 1KB] [ PDF 1303KB] ( 2570 )
4849 Indicative role and significance of bacterial pigments in aquatic environments
KAN Jia-wei, DUAN Li-qin, SONG Jin-ming, YUAN Hua-mao, LI Xue-gang
Bacterialchlorophyll (Bchl), as the main pigment of anaerobic photosynthetic bacteria (APB), serves as an important biomarker for studying paleoenvironmental changes in sediment. This paper provides a comprehensive review of the sources of bacterial pigments, distribution of APB, analytical methods for bacterial pigments, and its applications in indicating hydrological conditions in modern and ancient aquatic environments, polar ice cover changes, occurrence of hypoxia events and primary production. Bacterial pigments primarily originates from APB such as green sulfur bacteria (GSB) and purple sulfur bacteria (PSB) at the chemocline. PSB exhibits a higher carbon isotope fractionation compared to GSB. Due to the unique living environmental conditions of APB, the produced pigments can indicate changes in the depth of chemocline and the meromixis history of lakes. Currently, spectroscopy, chromatography and chromatography-mass spectrometry are the main analytical methods for bacterial pigments, with chromatography-mass spectrometry demonstrating advantages in bacterial pigment identification and quantification. The preservation of bacterial pigments in water and sediment is susceptible to physical, chemical and biological disturbances, and its stability is still uncertain. The analytical methods, and degradation and preservation mechanisms require further exploration and optimization to facilitate the widespread application of bacterial pigments in paleoenvironmental and paleoclimate reseaerch.
2023 Vol. 43 (9): 4849-4858 [Abstract] ( 185 ) [HTML 1KB] [ PDF 758KB] ( 1832 )
4859 Evaluation of urban greening cooling effect based on Spatio-temporal series observation
WANG Yu-bai, BAI Ting-ting, XU Dong, LI Ming-feng, TAN Ding
A general conceptual model based on systematic time-series observations was designed for Beijing, and the first Urban Greening (UG) cooling effect map for China from 2001 to 2018 was published. The study showed that there was a significant positive correlation between urban surface temperature (UST) and imperviousness, negative correlation between UST and imperviousness in the time dimension. In addition, the cooling effect of UG in the core and sprawling areas of Beijing was highly heterogeneous, with the cooling effect in the core area being approximately twice that of the sprawling area. Combining observed and simulated UST’s trends, this study quantified a cooling effect of 1.09K in Beijing, which mitigated 43.25% of the urban warming trend. However, the UST in Beijing has increased by 1.42K. Therefore, the construction of the urban thermal environment in Beijing still faces greater challenges. This study may provide a reference for mitigating potential warming’s trends due to future urban expansion.
2023 Vol. 43 (9): 4859-4867 [Abstract] ( 191 ) [HTML 1KB] [ PDF 1583KB] ( 1541 )
4868 Nitrate dependent ferrous oxidation in the sediments of Lake Taihu
CHEN Xiao-feng, WANG Run-zhu, ZHU Shi-ya, CHEN Jing
The sediments collected from different areas of Lake Taihu were anaerobically cultured, in combination with high-throughput sequencing and isotope enrichment technologies, to explore whether nitrate dependent ferrous [Fe(II)] oxidation (NDFO) can occur in the sediments of Lake Taihu, and whether Fe(II) addition can promote nitrogen removal from Lake Taihu. After anaerobic incubation for 24h, the concentrations of NO3−-N and Fe(II) in the overlying water decreased simultaneously, showing a significantly positive correlation (P<0.01). The relative abundance of NDFO related genera in cultured sediments increased from 0.69%±0.07% to 4.23%±0.90%. Combined with the change of sediment color, it can be inferred that NDFO occurred during anaerobic culture. The concentrations of NO3−-N in the control and the treatment added with lowest levels of Fe(II) (2.8mg) were significantly higher than those in other treatments (P<0.05, ANOVA), while the concentration of nitrite (NO2−) increased significantly with the increase of Fe(II) addition (P<0.01, ANOVA), indicating that a certain amount of Fe(II) can promote the reduction of NO3− and cause the accumulation of NO2−. After the addition of a small amount of Fe(II) (about 1.9mg/g sediment), the potential denitrification rate of the sediment in the different areas of Lake Taihu reached 213~252mg N/(m2·d), indicating that Fe(II) may play an important role in the denitrification process in Lake Taihu.
2023 Vol. 43 (9): 4868-4875 [Abstract] ( 232 ) [HTML 1KB] [ PDF 911KB] ( 1530 )
4876 Changes of vegetation ecological quality in the Chengdu-Chongqing economic circle from 2000 to 2020 and its response to extreme climatic factor
ZHANG Yan-jun, LI Zi-hui, GUAN Dong-jie, LI Zhen-liang
As the fourth pole of China's economic growth, the Chengdu-Chongqing economic circle has great responsibility to build a solid ecological barrier in the upper reaches of the Yangtze River, which is of great significance to the strategy of ecological environmental protection. In this study, based on the NPP and vegetation coverage FVC data from 2000 to 2020 in the Chengdu-Chongqing urban area, the vegetation ecological quality index (EQI) was constructed, and the spatiotemporal variation characteristics of vegetation ecological quality and the response of extreme climatic factors were analyzed. The results showed that: (1) from 2000 to 2020, the EQI in Chengdu-Chongqing area was generally stable and alternately up-down, and the average value of vegetation ecological environment quality for many years was 63.96; (2) the EQI in Chengdu-Chongqing urban area showed a spatial distribution pattern of low in the middle and high in the surrounding areas. The areas with large values of the average ecological environment quality index were mainly concentrated in the mountainous areas around the Chengdu-Chongqing economic circle, and the southeast area of Chongqing also has a high average EQI. The distribution of the average ecological environment quality index in the central region was similar between years with a little change; (3) from 2000 to 2020, the slope of ecological environment quality in Chengdu-Chongqing economic circle showed a good development trend. The areas with the minimum slope grades (-3.17~-0.42) were mainly distributed in Chengdu and the surrounding areas of Chongqing main city. The slopes of the ecological environment quality trend in the eastern and central parts of the Chengdu-Chongqing urban area showed a growing trend; (4) in the Chengdu-Chongqing economic circle, there are the significantly positive correlations at 0.01level between the EQI and the number of days with daily maximum temperature>25℃ (SU) in the extreme climate index, at 0.05level between the EQI and the number of days with daily maximum temperature higher than 90% of the quantile (TX90P), and at 0.05level between the EQI and the number of days with daily minimum temperature<0℃ (FD). Whereas, the EQI is of negative correlation at 0.05level to the number of days with daily minimum temperature higher than 90% of the quantile (TN90P). The results can provide a basis for understanding the changes of vegetation habitat quality and its response to extreme climate in the Chengdu-Chongqing economic circle.
2023 Vol. 43 (9): 4876-4885 [Abstract] ( 182 ) [HTML 1KB] [ PDF 1748KB] ( 1844 )
4886 Research advances in ladderane lipids of anammox bacteria
WANG Yi-cheng, YAN Peng, CHEN You-peng
Anaerobic ammonium-oxidizing bacteria (AnAOB) play an important role in the global nitrogen cycle and environmental pollution control. AnAOB contain unique ladderane lipids, whose key structure is three or five linearly concatenated cyclobutane moieties. Ladderane lipids have not been found in other bacteria so far, and their biosynthetic pathway and physiological function remain unknown. In this work, the advances in the discovery, structure, properties, types, applications, and synthesis of AnAOB ladderane lipids were comprehensively reviewed, and the current issues and prospected future research directions were discussed.
2023 Vol. 43 (9): 4886-4895 [Abstract] ( 251 ) [HTML 1KB] [ PDF 1387KB] ( 2030 )
4896 Effects of temperature and exogenous CaCO3 on the microbial degradation of ammonia nitrogen in waterworks sand filters
LIU Ming-hui, DING Cheng-long, ZHU Min, LI Yi, WU Jun-kang, JING Zhao-qian, YU Ran
In this paper, the ammonia degradation performance and variations of microbial community composition of the attached microbes in waterworks sand filters under different temperatures (10, 15, 25 and 37℃), ammonia concentrations (1 and 2.5mg-N/L) and exogenous addition of CaCO3 were investigated. The nitrifiers were successfully extracted from the sand filter in the waterworks, which included ammonia oxidizer, nitrite oxidizer and complete ammonia oxidizer as characterized by PCR- electrophoresis. The results of temperature influenced test showed that: the ammonia oxidation rate notably decreased by 48.1% and 47.3%, respectively under 1 and 2.5mg-N/L ammonia concentrations when the temperature decreased from 25℃ to 10℃. At 10℃, the system displayed high total nitrogen removal capacity (~48.1%), but the nitrite oxidation activity was significantly inhibited, and the increase of ammonia nitrogen concentrations exerted adverse effects on the nitrite oxidation. In contrast, the temperature as high as 37℃ caused the complete loss of the nitrification performance. Moreover, exogenous addition of CaCO3 significantly improved the ammonia oxidation rate by more than 90%. High-throughput sequencing results showed that a decrease in temperature (10℃ and 15℃) significantly inhibited the growth of Nitrosospira and Nitrosomonas (both relative abundance < 1%). When the temperature decreased to 10~15℃, Nitrospira outcompeted the other nitrifiers with the relative abundances increased by 63.3%-113.7%. Besides, the addition of CaCO3 caused a 2.5-fold increase in the relative abundance of Nitrospira, while the relative abundances of the other nitrifiers were all less than 1.0%. Therefore, it is inferred that the complete ammonia oxidation Nitrospira under cold condition had a high contribution to ammonia degradation.
2023 Vol. 43 (9): 4896-4904 [Abstract] ( 153 ) [HTML 1KB] [ PDF 1831KB] ( 1657 )
4905 Preparation and immobilization mechanism of weathered coal-immobilized microbial cells
JIAO Zi-le, LI Jian-hua, CHEN Xiao-jing, LU Jin-jing, GAO Chun-hua, XU Ming-gang
In this study, the modified weathered coal was used as the carrier to prepare for immobilized microbial cells by adsorption immobilization method. PBD (Plackett-Burman) and PBB (Box-Behnken) were used to optimize the immobilization process of microbial cells, so that the ability of this cells was maximized to passivate lead polluted water. A variety of characterization techniques were used to study the binding characteristics of microbial cells and carriers. These results showed that the quantity of microbial cells, immobilized temperature and pH were the key factors. When inoculation quantity was 7, the immobilized temperature was 31℃, and pH was 6.5, the unit Pb2+ adsorption capacity and removal rate of immobilized microbial cells could reach 313.83mg/g and 80.42%, which were 3.8times higher than free microbial cells. Compared with similar materials at home and abroad, it has a high level. Surface adsorption, pore filling, electrostatic attraction and covalent bonds (-OH, -NH2, -CONH2, -COOR) promote the immobilization of microorganisms on weathered coal jointly. This study can provide theoretical support for the preparation of immobilized microbial cells by weathered coal carriers.
2023 Vol. 43 (9): 4905-4915 [Abstract] ( 199 ) [HTML 1KB] [ PDF 2400KB] ( 1862 )
Emerging Contaminants and Environmental Toxicology
4916 Macroplastics and microplastics affect soil properties and cadmium bioavailability
CAO Yan-xiao, CHEN Tian-tian, CHEN Nuo, ZHAO Meng-jie, LI Hong-hu, SONG Yong-wei, HOU Jing-tao, ZHANG Jing-dong
In order to investigate the effects of macroplastics (>5mm) and microplastics on the transformation of heavy metal speciation in soil, macroplastics and microplastics with different doses (0.1%, 1%, and 7%) were mixed in cadmium (Cd) contaminated farmland soil for incubation to evaluate their impacts on soil properties, bioavailability and chemical speciation of Cd. Results showed that after 120 days of incubation, compared with the control treatment, macroplastics and 0.1% microplastics had less impact on soil pH, while 1% and 7% microplastics addition reduced soil pH by 0.13 and 0.36 units, respectively. Besides, the content of soil dissolved organic carbon (DOC) was increased by 6.45%~14.38% in the presence of macroplastics, but decreased by 17.10% in the presence of 7% microplastics. In addition, macroplastics showed little effect on Cd bioavailability, while microplastics increased the exchangeable fractionation and bioavailability of Cd in soil, and the effect was positively correlated with the dose. Among them, 7% microplastics increased the proportion of the exchangeable and carbonate-bound Cd by 12.77%, and the proportion of the Diethylene triamine pentaacetate acid (DTPA) extractable Cd was increased by 7.91%. The results of this study will provide a theoretical basis for preventing and controlling the combined pollution of plastic and heavy metals in agricultural soils.
2023 Vol. 43 (9): 4916-4925 [Abstract] ( 173 ) [HTML 1KB] [ PDF 616KB] ( 1956 )
4926 Pollution characteristics and exposure risk of PCDD/Fs from plastic waste recycling industry
YANG Yan-yan, LI Shi-ping, XIE Dan-ping, FU Jian-ping, DING Zi-rong, HAN Jing-lei, ZHANG Su-kun
The pollution level, emission characteristics and exposure risk of PCDD/Fs from a number of waste recycling enterprises were investigated in a certain province of China. The results showed that the TEQ values of PCDD/Fs in the flue gas samples ranged from 0.0796 to 0.478ng/m3(I-TEQ) with an average value of 0.194ng/m3(I-TEQ). In addition, the level of PCDD/Fs in plastic waste recycling industry was higher than the current standard limit(0.1ng/m3). The concentrations of PCDD/Fs in the ambient air samples of waste recycling enterprises area ranged from 0.256 to 2.15pg/m3 (I-TEQ) and the reference point ranged from 0.0356 to 0.178pg/m3(I-TEQ). The results of fingerprint analysis showed that high-chlorinated monomers including OCDF, OCDD, 1,2,3,4,6,7, 8-HpCDF and 1,2,3,4,6,7,8-HpCDD were the primary PCDD/F congeners in the flue gas and ambient air samples. 2,3,4,7,8-PeCDF was the most dominant congener contributing to TEQ values. The concentration of PCDFs was higher PCDDs in the ambient air samples, which was characterized by heat source. The exposure risk assessment suggested that human exposure to PCDD/Fs via inhalaition for the residents living in the studied area was at a relatively safe level. The contribution rate of respiratory exposure to PCDD/Fs for some individuals exceeded the evaluation standard and deserves more attention.
2023 Vol. 43 (9): 4926-4933 [Abstract] ( 159 ) [HTML 1KB] [ PDF 556KB] ( 1650 )
4934 Association between perfluoroalkyl substances exposures and depression in the adults: Based on NHANES 2005~2018
JU Ying-hui, WU Rui, WANG Meng-lin, GAO Ya, ZHU Yue
To investigate the relationship between perfluoroalkyl substances (PFAS) exposure and the risk of adult depression. We integrated the data in National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2018, and recruited a total of 5424 men and 5438 women. We examined the association between four PFAS exposures, including perfluorooctanoic acid (PFOA), perfluorooctanesulfonate acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and the risk of adult depression using a weighted logistic regression model and restricted cubic spline curves. Subgroup analysis was also conducted according to gender and age. After adjusting for all covariates, higher exposure to PFOA, PFOS, PFHxS, and PFNA significantly reduced the risk of depression. Compared to the first quartile (Q1), the odds ratios of the groups with the fourth quartile (Q4) level of PFOA, PFOS, PFHxS and PFNA were 0.519 (95%CI: 0.367~0.735), 0.612 (95%CI: 0.422~0.887) and 0.608 (95%CI: 0.422~0.875) and 0.658 (95%CI: 0.467~0.927), respectively. Restricted cubic splines showed a negative linear dose-response relationship between PFAS exposure and the prevalence of depression. Subgroup analysis found that the negative association between PFAS exposure and depression was more significant in women and individuals aged 18~39 years, respectively. Our study suggests a negative association between PFAS exposure and adult depression risk, with gender and age differences. However, more investigations are needed to confirm our findings.
2023 Vol. 43 (9): 4934-4941 [Abstract] ( 206 ) [HTML 1KB] [ PDF 895KB] ( 3991 )
4942 Bioinformatics-assisted zebrafish model reveals the mechanism of EHDPP-induced metabolic disease
NI An-yu, LI Jin-yun, FANG Lu, WAN Ke-wei, CHEN Yang, WANG Hui-li, YAN Jin
This study utilized data mining from public databases, such as CTD and GEO, to demonstrate that EHDPP has the risk of inducing metabolic diseases by modulating various cell membrane receptor-mediated biological signaling pathways, which are related to the development of metabolic disorders and inflammation. Then, zebrafish larvae were utilized as models and exposed to a sublethal dose of EHDPP in order to validate the aforementioned findings. The findings revealed that after 5days of 500μg/L-EHDPP exposure, the content of triglycerides and total cholesterol in zebrafish larvae increased by 53.8% and 32.1%, respectively. Additionally, qRT-PCR results indicated that the lipid metabolism pathway mediated by Pparγ may serve as a potential pivotal mechanism for the induction of abnormal lipid accumulation in zebrafish caused by EHDPP.
2023 Vol. 43 (9): 4942-4950 [Abstract] ( 157 ) [HTML 1KB] [ PDF 1799KB] ( 2316 )
4951 Air pollutant exposure levels of different travel modes at short distances
GENG Yi-shuo, LI Sai, WU Peng-peng, QI Ling, CAO Su-zhen, DUAN Xiao-li
To investigate the differences in air pollutant exposure levels of commuters under different travel modes and to provide a scientific basis for health protection from air pollutant exposure during short-distance travel, portable individual air exposure monitors were used to monitor the exposure of five air pollutants (NO2, CO, O3, PM2.5 and PM10) at a fixed route in Beijing on four travel modes: bus, subway, bicycle and car. The key findings are: (1) At the same ambient air pollution level, the exposure levels of air pollutants among different travel modes were significantly different. Travel by subway had the highest exposure level of NO2 (46.46μg/m3). Exposure level of CO (1334.99μg/m3) when travel by bus was slightly higher than those using the other three travel modes. Cycling has the highest exposure level of O3(28.83μg/m3), PM2.5(21.98μg/m3) and PM10 (25.57μg/m3). (2) Considering travel time and inhalation rate, travel by bicycle has the highest exposure doses of NO2, CO, O3, PM2.5 and PM10, followed by bus, subway and car. (3) Ambient pollutants’ concentrations strongly affect individual exposure levels for different travel modes. When the ambient NO2 and CO concentrations are low (NO2 £ 18μg/m3, CO £ 300μg/m3) and O3 concentrations are high (O3 > 65μg/m3), the individual exposure concentrations of the three pollutants are lower for subway travel than for other modes. In contrast, when the ambient NO2 and CO concentrations are high (NO2 > 18μg/m3, CO > 500μg/m3) and O3concentrations are low, individual exposure concentrations of the three pollutants are lower for car travel. When ambient concentrations of particulate matter are low (PM2.5 £ 20 μg/m3, PM10 £ 30 μg/m3), exposure levels for subway and bus are relatively lower. When choosing their travel modes, commuters should consider both the ambient air pollution levels and their travel needs. We suggest choosing public transportation mode instead of private cars for short-distance travel need when ambient air quality is great for health benefit.
2023 Vol. 43 (9): 4951-4960 [Abstract] ( 223 ) [HTML 1KB] [ PDF 700KB] ( 1752 )
Carbon Emission Control
4961 Development status of global greenhouse gas remote sensing satellite industry
QIN Bing-xue, ZENG Jing-jing
Compared with the ground-based greenhouse gases (GHGs) observation network, which is affected by the uneven distribution of stations, high precision and resolution remote sensing satellite monitoring has been rapidly developed as an effective means to obtain GHGs concentration information. In recent years, Japan, the European Union, the United States, Canada and China are actively planning to launch greenhouse gas remote sensing satellites and lay out the satellite networks. By reviewed the main greenhouse gas satellite observation technologies, deployments and application examples, the development status of greenhouse gas remote sensing satellite industry were summarized. On the one hand, the GHGs remote sensing satellite industry needs to make further breakthroughs in remote sensing imaging, satellite networking, cooperative observation between sky and ground, data processing and capital investment. On the other hand, it is necessary to strengthen the research of related field on high precision satellite, data assimilation system, sky-ground cooperative observation, inversion algorithm and satellite recycling technology. Meanwhile, in order to make further progress in the international competition, China's GHGs remote sensing satellite monitoring industry should actively develop in scientific and technological innovation and strategic deployment, supporting private capital investment, and participating in international exchanges and cooperation.
2023 Vol. 43 (9): 4961-4974 [Abstract] ( 228 ) [HTML 1KB] [ PDF 919KB] ( 5604 )
4975 Incentive effects of marine carbon sink on carbon emission disclosure: An analysis considering purchase price from a game-theoretic perspective
ZHANG Feng-xuan, HE Yi-xiong, WANG Yan-wei, XIE Su-mei, LIU Run-zi, XU Min
To fully leverage the offsetting effect of marine carbon sinks, enhance the quality of carbon emission information disclosure by high-carbon emitting enterprises, and realize the value of marine carbon sinks, the actual role and value of government regulation, media supervision, and the net benefits brought by marine carbon sinks in encouraging high-carbon emitting enterprises to disclose real information were compared and demonstrated using evolutionary game analysis. Additionally, the formation of prices for marine carbon sinks was explored based on differential game theory. The results indicated that strict government regulation and media supervision tended to trap enterprises in an unstable state of decision-making. In contrast, the higher net benefits brought by marine carbon sinks proved to be more effective in maintaining enterprises in a stable state of disclosing real information. Marine carbon sinks were found to possess significant potential in terms of ecological and economic value. Under the premise of fully respecting the market, a reasonable equilibrium price could be formed through government coordination, bargaining efforts, and other means. Moderate regulation, supervision, and a rational price for marine carbon sinks served as powerful safeguards in enhancing the quality of carbon information disclosure by high-carbon emitting enterprises.
2023 Vol. 43 (9): 4975-4987 [Abstract] ( 197 ) [HTML 1KB] [ PDF 2735KB] ( 1865 )
4988 Assessment of the relative contribution of climate change and land use change on net primary productivity variation in the middle and lower reaches of the Yangtze River Basin
XU Yong, LU Yun-gui, DAI Qiang-yu, ZHAO Chun, HUANG Wen-ting, CHEN Tian-wei, ZHANG Yan
Quantitatively distinguishing the relative contribution of climate change and land use change on the net primary productivity (NPP) variation of vegetation ecosystems in the middle and lower reaches of the Yangtze River Basin at regional and grid scales can provide reference for regional ecological environment protection and vegetation resource management. The spatio-temporal variation and its future changing trend of the vegetation ecosystem NPP in the middle and lower reaches of the Yangtze River Basin were firstly explored using Theil-Sen Median analysis, Mann-Kendall significance test, and rescaled range (R/S) analysis based on MODIS data, meteorological data, and land use type data. The relative contribution of climate change and land use change on the vegetation ecosystem NPP in the middle and lower reaches of the Yangtze River Basin were then quantitatively distinguished by relative contribution analysis on the basis of scenario settings. Results showed that, on the temporal scale, the vegetation NPP had fluctuated and increased in the middle and lower reaches of the Yangtze River Basin from 2000 to 2021 with a magnitude of 6.99g/(m2·a). The NPP of forest land, grassland, and cultivated land ecosystems showed upward trends. The increasing rates of NPP in descending order were observed in forest land, grassland, and cultivated land ecosystems with magnitudes of 9.79g/(m2·a), 8.84g/(m2·a), and 2.34g/(m2·a), respectively. On the spatial scale, the changing rate of vegetation NPP presented a spatial distribution pattern of "high in the south and low in the north" of the study area. In the middle and lower reaches of the Yangtze River, the proportion of areas with NPP increase in the whole region as well as forest land, grassland, and cultivated land ecosystems was larger than the proportion of areas with NPP decrease, among which, the proportion of areas with NPP increase in forest land and grassland ecosystems was 91.43% and 91.48% respectively. The proportion of the area with NPP increase in the future was smaller than that with NPP decrease in the study area. The relative contribution of climate change and land use change can be obtained on the basis of the results of the relative contribution analysis that, on the regional scale, the relative contribution of climate change and land use change on the NPP variation of vegetation ecosystem in the study was 85.60% and 10.85%, respectively. Furthermore, the NPP variation in forest land ecosystem and grassland ecosystem was dominated by climate change dominated, while the NPP variation in cultivated land ecosystem was dominated by land use change. On the grid scale, the proportion of the areas with NPP variation dominated by land use change accounted for 54.99% in the cultivated land ecosystem and 56.91% in the grassland ecosystem in the study area, respectively. The proportion of the areas with NPP variation dominated by climate change account for 71.96% in the forest land ecosystem. The relative contribution of other factors on the NPP variation in cultivated land ecosystem was higher than that in forest land and grassland ecosystems.
2023 Vol. 43 (9): 4988-5000 [Abstract] ( 217 ) [HTML 1KB] [ PDF 5985KB] ( 1994 )
Environmental Impact Assessment and Management
5001 Study of urban multi-source solid waste collaborative disposal mechanism and park planning method
WEN Zong-guo, ZHANG Jia-yue, FEI Fan, DU Hao-yan, CHEN Yan, BAI Wei-nan
Based on the physical and chemical characteristics of municipal solid waste, such as household waste, kitchen waste and hazardous waste, and the metabolism characteristics of disposal facilities, this paper put forward three collaborative disposal mechanisms of waste disposal park, systematically sorted out the collaborative points of 8typical solid waste disposal technologies, such as incineration, landfilling and anaerobic digestion, etc., and developed a four-step planning method including waste generation prediction, flow stimulation and demand analysis, technology selection and scale matching, and quantitative evaluation. Empirical analysis based on Chang’an Vein Industrial Park in Chengdu showed, by considering collaborative mechanism and adopting this planning method, the park annual solid waste disposal volume would increase 61.3% than base year, annual power generation would be 1.361billion degrees, annual CO2 emission would reduce 639,800tons, waste reduction rate would reach 67.8%, the fly ash and slag would be completely safely treated, and the waste water recycling rate would reach 80.3%. The correlation degree of this park could reach 0.33, which would form a new resource recycling base, integrating collaborative disposal of solid waste, supply of energy and production of building materials.
2023 Vol. 43 (9): 5001-5010 [Abstract] ( 384 ) [HTML 1KB] [ PDF 979KB] ( 2437 )
5011 Research on the impact mechanism of property right division on the integrity of forest ecosystem
ZENG Xian-gang, DUAN Cun-ru
Excessive property right division leads to fragmentation of forest ecosystem, resulting in "fence effect" and reducing the integrity of forest ecosystem. Based on the data of the 6th, 7th and 8th national forest resources inventory, this study takes Shanxi Province, Jilin Province and Jiangxi Province as the research objects, and uses the generalized progressive DID method to analyze the impact mechanism of property right division on forest ecosystem integrity. The level of forest ecosystem integrity in each province is not high, and the regional difference is obvious. The property right division has a negative effect on the forest ecosystem integrity, which leads to a significant decline in the community composition and structure index, but will have a positive impact on the landscape pattern. Biodiversity plays an intermediary role between property right division and forest ecosystem integrity. Property right division has a negative impact on biodiversity, and has a negative impact on ecosystem integrity by changing biodiversity. This study provides a practical reference for further innovation of the property rights system of natural resources.
2023 Vol. 43 (9): 5011-5019 [Abstract] ( 160 ) [HTML 1KB] [ PDF 423KB] ( 1630 )
5020 Improving municipal solid waste management practices in Ningbo
ZHU Fen-fen, ZHAO Bing, LIU Xiao-yan, WANG Huan, ZHOU Tian-tian, WANG Yi-yu, QIU Yu-qun
Ningbo, a city in southeastern China, was selected as the research city. The participant observation method and semistructured face-to-face interviews were used to get a comprehensive understanding of municipal solid waste (MSW) management in the Chinese city, followed by Wasteaware model to rank the waste management practices. The results showed that the recycling rate, recycling quality and governance factors of MSW were not ranked high in Ningbo City. San Francisco’s pay-as-you-throw (PAYT) program and material recovery facility (MRF), as well as Munster's duales system deutschland (DSD) system, should be studied. The informality that exists in the recycling process can be improved, and residential sorting behavior along with financial sustainability can be increased. In Ningbo, large multifamily buildings are more prevalent, which make a flat rate easy to implement. PAYT need further development of source traceable compostable bags/bins to be supervised and strictly enforced laws. The combination of MRF and formal manual sorting will give a better recovery rate. In Ningbo, DSD may enhance at least 3%~5% excess expense of a plastic enterprise, which need government take the leading role. Ningbo needs more time to internalize MSW sorting action as moral norms even as social norms. In addition, the continuous delivery of the results expected by the residents of local government is essential to create a virtuous cycle.
2023 Vol. 43 (9): 5020-5030 [Abstract] ( 191 ) [HTML 1KB] [ PDF 1281KB] ( 1791 )
5031 Study on the carrying capacity of “ecology, environment and resources” based on visualization analysis
DUAN Hai-xu, ZENG Wei-hua, CHEN Jia-jun
In order to further investigate the scientific research level, research hotspots and development trend about the carrying capacity of global "ecology, environment, and resources", in this work, the core collection database of the Web of Science was used to search the literature from 1990 to 2021. Besides, CiteSpace and VOSviewer analytic tools were utilized to visualize and assess the carrying capabilities, and the results indicated that the number of relevant publications presented an overall increasing trend. China is ranked first in the comprehensive ranking for international collaboration. The Chinese Academy of Sciences held the dominant position in the number of publications among scientific organizations. The research hotspots primarily focused on water environmental, ecological and resource carrying capacities and their interrelationships. The priority research areas included the sustainable development, various carrying capacities and the ecological relationship between them. Environmental and ecological science is the main research area. The publications by Shen Liyin ranked 1st, and the author with the highest frequency of co-citation was Wackernagel M. 《Desalination and Water Treatment》 had the most number of publications. 《A new scenario framework for climate change research: the concept of shared socioeconomic pathways》 was the most cited paper. It is obvious that the studies on the carrying capacities of ecological, environmental and resource had received the extensive attention of scholars. Therefore, the summary and analysis of relevant research status and application trends from this article were conducive to the synergistic thinking on the goals of ecological environment and resource.
2023 Vol. 43 (9): 5031-5040 [Abstract] ( 245 ) [HTML 1KB] [ PDF 1991KB] ( 1853 )
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