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Analysis of the Spatial Patterns of Particulate Pollution in the Persistent Haze in Northeast China: A Case Study in Harbin City Texte intégral
2020
Lei Wang, Jiarong Deng, Lijin Yang, Yunlong Yao , Dawei Xu
With the help of PM2.5, PM10, and the Air Quality Index (AQI) and other air quality data, the posterior trajectory model of the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT-4) model, having researched fire points of the straw in Harbin City, spatial pattern characteristics and genesis of the persistent haze in Harbin City from 20th October 2016 to 11th November 2016 were analysed. During the study period, the highest value of PM2.5 reached 1880?g/m3, the PM10 reached 1411?g/m3, the daily average concentration was high, and the AQI concentration reached a maximum value on 28th October and 4th November, and the persistent haze phenomenon was the most significant. Besides, the study found that the haze incident and a large quantity of pollutants due to the concentration of burning straw around Harbin had a strong connection. The burning of particulate matter had a significant impact on the region’s pollution level. The results of this study contribute to the control of particulate pollution in winter cities of developing countries.
Afficher plus [+] Moins [-]Effects of Soybean Stover-Derived Biochar on Microbial Community and Structure in Loess Soil Texte intégral
2020
Baowei Zhao, Alexandar J. Niebuhr, Yude Lv , Khamhak Douangdalangsy
Soil microorganisms play a crucial role in nutrient availability and overall soil health. However, the effects that biochar has on soil microbial communities are not well understood. This study analysed the effects of biochar pyrolysis temperature and application rate on the soil microbial community of loess. Two biochars derived from soybean stover were produced at 300 and 600°C (BC300 and BC600, respectively) and were applied to loess at the rates of 1, 3, and 5% (w/w). After fifteen weeks of incubation, soil microbial analysis was performed using 16S rDNA amplicon sequencing technology. All of the BC300 and BC600 treated soils were shown to have an increase in the relative abundance of Gemmatimonadetes and a decrease in Actinobacteria and Chloroflexi. Proteobacteria also showed a significant increase in the majority of the biochar treated soils. Biochar led to a shift in the soil microbial community and caused a significant increase in the relative abundance of bacteria from the genus Lysobacter. Based on the results of this study, soybean stover-derived biochar should be considered as a potential soil amendment for improving the health of loess or other soils in semi-arid climates.
Afficher plus [+] Moins [-]Heavy Metal Accumulation in Soil-Wheat System of Coal Mining Area and Health Risk Assessment: A Case Study in Northern Anhui Province, China Texte intégral
2020
Q. Li and S. B. Zhou
An investigation of 43 soil samples and their corresponding wheat samples collected from Qinan (QN) and Luling (LL) coal mining areas in Suzhou, China, was conducted to study the accumulation of heavy metals (Cu, Pb, Zn, Cd, Cr and Ni) in the soil-wheat system, and to evaluate the potential human health risk posed by heavy metals from long-term ingestion of local wheat. Results showed that Cu, Zn, Cd and Ni were accumulated in the soils from the two mining areas, higher proportions of all the investigated metals in residual fraction were recorded, while large amounts of Cd, Cu, Zn, Pb were also observed in the bioavailable or potential bioavailable fractions. Metal contents in the different parts of wheat mainly followed the order of Root>Stem>Grain. The trends of Bioaccumulation factor (BF) and Translocation factor (TF) values were Zn>Cd>Cu>Ni>Pb>Cr and Cu>Cd>Zn>Cr>Pb>Ni, respectively. Correlation analysis suggested that the accumulated metals in the grain were mainly supplied from exchangeable and carbonate bound fractions in soil. Since the health risk posed by heavy metals ingestion was very close to the maximum allowable limit, the safety of wheat consumption in the coal mining areas should be continually concerned.
Afficher plus [+] Moins [-]Comprehensive Assessment of Water Supply Benefits for South-to-North Water Diversion in China from the Perspective of Water Environmental Carrying Capacity Texte intégral
2020
Haitao Chen, Xiaonan Chen, Lin Qiu, Wenchuan Wang
The South-to-North Water Diversion Project in China is an important measure to promote the ecological civilization construction in the receiving areas. Since the operation of the east and middle routes, the comprehensive benefits are more and more remarkable. It is very significant to quantitatively evaluate the comprehensive benefits of the South-to-North Water Diversion Project. The idea of quantitative evaluation by the improved degree of the carrying capacity of regional water environment after water diversion is put forward in this paper. On the basis, combining with variable fuzzy set and cloud theory, a new comprehensive assessment model is established. According to the evaluation index system of water environmental carrying capacity and the index values of research area, the linear difference function value is generated randomly by triangular forward cloud generator, and then the variable fuzzy comprehensive evaluation is carried out. Taking Haihe River Basin and Beijing City as typical research areas respectively, the comprehensive benefits of water supply from the diversion project in 2030 are analysed. The comprehensive evaluation method with variable cloud model considers both “good” and “bad” aspects and considers both randomness and fuzziness. Results show that the model is feasible and efficient. It is worth popularizing and applying.
Afficher plus [+] Moins [-]Centrifugal Reduction Treatment Process for High-Water-Content Sludge in Oilfield Texte intégral
2020
Xingwang Wang, Jiwei Wang and Shuangqing Chen
To ensure that injection water quality reaches the standard, oil field sewage stations adopt a continuous sludge dredging process to reduce the content of suspended solids and sand. A large amount of highwater- content oily sludge is produced, which results in increased costs of transportation and subsequent harmless treatment. Therefore, a sludge reduction treatment is necessary. A set of centrifugal reduction processes for oily sludge was designed in this study, with the horizontal screw centrifuge as the key piece of equipment. In the laboratory, CPAM flocculant was screened. In the field test, the effects of four factors rotational speed, differential speed, the feeding quantity of sludge, and flocculant dosage on the reduction effect were determined. The results show that when the rotational speed is higher, the differential speed is lower, and the feeding quantity of sludge remains lower, and the flocculant dosage remains higher, after treatment, the water content of the sludge is lower and the solid content of the sludge is higher. The optimal parameters of the centrifugal reduction process were determined using an orthogonal experimental design as follows: rotational speed 2,607 rpm, differential speed 8 rpm, the feeding quantity of sludge 7 m3/h, and flocculant dosage 100 g/m3. After treatment, the average water content of the sludge decreased from 92.75% to 56.57%, and the average solid content of the sludge increased from 2.30% to 36.72%. The split ratio of the water-outlet and sludge-outlet was in the range of 8.71:1 to 12.57:1, and the corresponding sludge reduction ratio was 89.70% to 92.63%, confirming successful sludge reduction.
Afficher plus [+] Moins [-]Influence of Tannery Effluents on Morphological Characters of Ipomoea pes-caprae (L.) Sweet and Clerodendron inerme (L.) Gaertn. Texte intégral
2020
A. Venkatesan
Tannery industry is common in many parts of the world, which is polluting groundwater ecosystems and producing major heavy metals and sodium chloride. The present study is aimed at some morphological characters in phytoremediation of heavy metals and ions from tannery effluents by using halophytic species such as Ipomoea pes-caprae and Clerodendron inerme. The morphological characters were analysed at an interval of 30, 60, 90 and 120 days. The results indicated that all the morphological characters were increased with an increasing concentration of tannery effluents and no injury symptoms in growth condition. It may be concluded that these halophytic species are potentially suitable for phytoremediation of heavy metals from the tannery effluent contaminated soils, which will reclaim the soil for further use as crop cultivation or crop improvement.
Afficher plus [+] Moins [-]Changes in Enzyme Activity and Bacterial Succession During Sewage Sludge Composting Texte intégral
2020
Chuang Ma, Hui-jia Jin, Bin Hu, Nan Liu, Ke Zhang, Ji-hong Zhao , Hong-zhong Zhang
To study the variations in microorganisms and enzyme activity during sewage sludge composting, the dynamic changes in temperature, enzyme activity and microorganism composition were studied by co-composting municipal sludge and corn straw. The results show that the pile underwent mesophilic, thermophilic, and cooling phases and that the high-temperature duration (³ 50 °C) had reached 5 days, which meets harmlessness requirements. During the composting process, the protease, arylsulfatase (ARS) and cellulase content increased gradually; urease content first decreased and then increased rapidly; and peroxidase (POD) content first increased and then decreased. Ureibacillus, Bacillus, Pseudomonas, Flavobacterium and Sporosarcina were the dominant bacteria during sludge composting. Microorganisms played different roles at different stages of the composting. Ureibacillus and Bacillus were the dominant strains in the mesophilic and thermophilic phases, respectively, and Pseudomonas and Flavobacterium were the dominant strains in the cooling phase. Sporosarcina mainly played a role later in the thermophilic and cooling phases. The effect of different bacteria on enzyme activity varied; Pseudomonas played a clear role in promoting the production of urease while Bacillus had a clear inhibitory effect on the production of urease. Ureibacillus inhibited the production of ARS, POD, protease and cellulase. By studying the changes in microbial and enzymatic activities at different stages of sludge composting, it is possible to thoroughly explore the nature of the latter and provide a reference for optimizing composting processes.
Afficher plus [+] Moins [-]Study on Removal of Thallium from Wastewater by Chitosan/Fly Ash Composite Adsorbent Texte intégral
2020
Li Hai-hua, Chen Jie, Hua Yong-peng, Yan Shao-feng, E. Zheng-yang and Su Hang
Thallium (TI) is a kind of emerging contaminant with strong toxicity. In this study, a low-cost, renewable, biologically low-toxic and environmentally friendly fly ash/chitosan (FACS) composite adsorption material was synthesized by combining the characteristics of chitosan and fly ash to remove thallium from wastewater. SEM, FTIR and XRD analyses showed that the adsorbent mainly contained silicate compounds, and the surface of the particles contained a large number of micro porous structures. The adsorption process was rapid, reaching the adsorption equilibrium after 60min. When the pH value was 8, FACS had the best adsorption effect on TI, which was not conducive to the adsorption of TI in either strong acid or strong base environment. The co-existence of Fe3+ and Mn2+ could facilitate the adsorption of TI by FACS. The adsorption isotherm data were better fitted for the Freundlich model, while the Second-order kinetic model was more suitable for describing the kinetic data. Since the main chemical bond composition and chemical groups of FACS would not change after the adsorption of TI, the removal rate of TI was still high when it was reused after desorption. Because of its simple operation, low cost and reusability, FACS is considered to have certain potential in the removal of TI from wastewater.
Afficher plus [+] Moins [-]Capital Allocation Efficiency Evaluation of Energy Conservation and Environmental Protection Enterprises in the Yangtze River Delta of China Texte intégral
2020
Hongjun Xiong
Various measures are implemented to promote the construction of China’s ecology. These measures aim to accelerate the green transformation of the economy and promote the rapid development of energy conservation and environmental protection industry under the promotion of relevant policies. Consequently, the numbers of enterprises and the market scale have shown explosive growth. However, energy conservation and environmental protection enterprises are faced with lack of technological innovation, shortage of capital, and high cost. Effective measures must optimize the efficiency of capital allocation. To evaluate the capital allocation efficiency of energy conservation and environmental protection enterprises, 26 listed companies of energy conservation and environmental protection in the Yangtze River Delta of China were selected as samples. Monetary capital, accounts receivable, inventory, fixed assets, and construction in progress were used as input scalars. Net profit, undistributed profit, and surplus reserve were used as output variables. The Data Envelopment Analysis (DEA) model was used for analysis. Results show that capital allocation efficiency of 11 sample companies is DEA-effective. Power, heat, gas, water production, and supply industry rank first with the real estate industry divided by industry. Shanghai ranks first in the regional division. Specific improvement strategies are proposed for non-DEA effective sample enterprises.
Afficher plus [+] Moins [-]Comparative Assessment of Trace Metal Concentrations and Their Eco-Risk Analysis in Soils of the Vicinity of Roundhill Landfill, Southern Africa Texte intégral
2020
Nyika Joan Onyari Ednah, Megersa Olumana Dinka , Shivani Bhardwaj Mishra
Soil is a vital media in transmitting contaminants in the environment. Contamination of soils by trace metals has received much attention due to their associated toxicity, persistence, bioaccumulation and non-biodegradability that is harmful to the ecology. This study assayed the concentrations of trace metals in topsoils of the vicinity of Roundhill landfill using inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray fluorescence (XRF), compared the detection capabilities of the two techniques and determined ecological risks of the contaminants using geographical information system. Soils were collected from nine sampling sites around Roundhill landfill in the Eastern Cape and analysed for five trace metals using the two techniques. Mean concentrations of Cr, Cu, Ni and Zn determined by ICP-MS and XRF were normally distributed (p<0.05) from the parametric test while no significant differences between the two datasets were established from the non-parametric test. Under-estimated elemental concentrations determined by XRF were attributed to its high detection limits, matric effects, inter-elemental peak interferences and low sensitivity of the equipment. Correlation values of Cr, Cu and Ni showed a high degree of linearity compared to Pb. Evaluated eco-risk indices revealed low to extremely high ecological risks, posed by assessed trace elements in soils. Cr had the highest potency. Assayed trace metals were ecologically harmful to soils and their origin was linked to landfill leachate pollution.
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