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Upflow Anaerobic Filter for the Treatment of Wastewater from a Natural Rubber Latex Concentration Unit Texte intégral
2021
Nithya Gopinath, Madhu G. and Joseph Francis
In this study, wastewater from a centrifuge rubber latex concentration unit was experimentally treated by an up-flow anaerobic filter (UAF) at variable hydraulic detention time to investigate the COD removal efficiency and the gas production rate. The UAF reactors were made of PVC pipe with an inside diameter of 9.5 cm, 180 cm in height, with a bed volume of 12.8 L, and filled with polyethylene media. The initial COD concentration of wastewater was in the range 4620 - 10400 mg.L-1. HRTs were controlled at 20 days, with the organic loading rate varying from 2.9 to 10.5 kg.day.m-3. The findings show that the COD removal efficiency of the system was in the range of 85% to 92% for the varying organic loading rates. In addition, the specific methane production rate varied from 8.2 to 14 L of CH4 produced/g of COD destroyed/day for the different organic loading rates.
Afficher plus [+] Moins [-]Assessment of Soil Environment Pollution Based on Fuzzy Pattern Recognition Model Texte intégral
2021
Xin Huang and Lin Qiu
As one of the basic elements of the ecosystem and natural environment, the soil is closely related to human life. However, the problem of soil environment pollution is becoming more and more serious, which needs to be solved urgently. It will provide a reference for solving the problem of soil environment pollution if a suitable method can be found to evaluate the degree of soil environment pollution. The degree of soil environment pollution belongs to the fuzzy concept. It is a fuzzy pattern recognition problem to evaluate the degree of soil environment pollution according to the soil environment level standard value. The fuzzy pattern recognition method of soil environment pollution assessment makes full use of the fuzzy characteristics existing in soil environment assessment, considers the common influence of the weight of evaluation factors and the index value, and also considers the correlation between indexes and the similarity of index characteristics of different sampling points, therefore, the interference of some man-made certain factors is concealed. The model was applied to the soil sampling point in Wudi County of Shandong Province in the Yellow River basin of China. The results showed that the evaluation of soil environment pollution by this method accorded with the actual situation and can provide a basis for ensuring the stability of soil ecological environment, improving the quality of cultivated land, and improving regional ecological conditions. At the same time, in view of the current problem of soil environment pollution, the paper calls on human beings to pay attention to environmental protection and be responsible for their own safety and also proposes four aspects of treatment schemes and measures.
Afficher plus [+] Moins [-]Surface Water Pollution Risk From Vietnam Water Quality Index (VN-WQI) in the Ca Mau City, Mekong Delta Texte intégral
2021
Nguyen Ngan Ha, Tran Thi Thu Huong, Pham The Vinh and Tran Thi Van
This paper presents the study of integrating the remote sensing technology with in-situ ground observation for assessing the status of water quality in Ca Mau city through the Vietnam Water Quality Index (VN-WQI). The Sentinel-2 image and in-situ surface water samples were collected on 20 February 2020 for this study. The sample results were then specified by samples’ coordination. Besides, Sentinel-2 imaging was processed by radiometric and atmospheric correction, geometric registration, and extracted pixel spectral values from the sample locations. The multiple linear regressions of seven water quality parameters including BOD5, COD, NH4, PO4, TSS, pH, Coliform with surface water’s pixel spectral values from the satellite images were calculated and used to simulate water quality parameters on the satellite image. They were integrated into the VN-WQI to estimate, classify, and evaluate the general surface water quality of the Ca Mau city. The results show that there is a regressive correlation between measured data and image spectral values, and the simulation also well fits with the data with an acceptable error. The surface water quality of Ca Mau city is heavily polluted with almost all water quality parameters recognized at B1 to above B2 level according to the QCVN08-MT:2015/BTNMT. In terms of VN-WQI, the results also illustrate the low quality of surface water and heavy pollution only used for water transportation, not for domestic use. This approach can be a powerful method in spatially monitoring water quality and supporting environment management.
Afficher plus [+] Moins [-]Application of Cationic Surfactant Modified Mengkuang Leaves (Pandanus atrocapus) for the Removal of Reactive Orange 16 from Batik Wastewater: A Column Study Texte intégral
2021
Megat Ahmad Kamal Megat Hanafiah, Shariff Ibrahim, Nur Izah Fasihah Mohamad Subberi, Nesamalar Kantasamy and Is Fatimah
The feasibility of Mengkuang leaves (Pandanus atrocarpus) as a non-conventional low-cost adsorbent for the removal of an anionic dye, Reactive Orange 16 (RO16), was investigated. Among the dyes that have been commonly used in the Batik industry was reactive dye. In this study, Mengkuang leaves were chemically modified with cetyltrimethylammonium bromide (CTAB), a cationic surfactant, to improve their adsorption performance toward anionic dyes. The adsorbent’s morphological characteristics were analyzed using a scanning electron microscope (SEM). The surface of modified Mengkuang leaves seems to be irregular and uneven, with more porous structures than raw Mengkuang leaves. Adsorption of RO16 dye in fixed bed column using modified Mengkuang leaves adsorbent indicated the breakthrough time increased at higher bed height and lower flow rate. The breakthrough times for bed height of 0.5, 2, and 4 cm were at 16, 68, and 165 min, respectively. Meanwhile, breakthrough time for the flow rate of 2,5 and 7 mL.min-1 were at 327, 104, and 43 min, respectively. However, the study utilizing raw Mengkuang leaves showed no significant removal of RO16. Thus, it can be concluded that the cationic surfactant modification of Mengkuang leaves is advantageous for anionic dye removal. This anionic dye removal is significantly influenced by column parameters such as bed height and flow rate as the plotted breakthrough curves obtained from experimental data were similar to the typical breakthrough curve. When applied to the Yoon-Nelson model, the adsorption data provided the best fit with the R2 value above 0.95. The time taken for the breakthrough is very similar to model prediction values. Experiments with real batik dye wastewater showed the immense potential of modified Mengkuang leaves where total removal of real Batik wastewater was instantaneous.
Afficher plus [+] Moins [-]Solid Selective Catalytic Reduction: A Promising Approach towards Reduction of NOx Emission from Exhaust of CI Engines Texte intégral
2021
M. K. Yadav and A. K. Srivastava
The rising rate of pollution in urban areas has become a worldwide concern in recent years. Diesel engines are considered one of the largest contributors to environmental pollution caused by exhaust emissions, and they are responsible for several health problems as well. Diesel engines contain carbon monoxide, carbon dioxide, unburned hydrocarbons, and oxides of nitrogen. The reduction of Nitric oxides (NOx) emission from diesel engine exhaust is currently being researched by automotive manufacturers. After much research, selective catalytic reduction (SCR) technology was discovered to be effective in reducing nitrogen oxide emission from diesel engine exhaust. This paper is an attempt to explore the problems associated with the use of selective catalytic reduction (SCR) and compares selective catalytic reduction (SCR) with the latest technology named solid selective catalytic reduction (SSCR) for efficient reduction of NOx emission from the exhaust of diesel engines. The issue of contamination, malfunctioning, and freezing of diesel exhaust fluid (DEF) at low temperatures are the major problems associated with the application of SCR. It is observed that by controlling the quantity of ammonia slip, SSCR can give better performance in the reduction of NOx emission from the exhaust of diesel engines.
Afficher plus [+] Moins [-]Erosion Resistance and Fertility of Frost-Resistant Ecological Substrate in Alpine Region Texte intégral
2021
Cailing Xue, Ailinaizaier Ainiwaer, Jiazhen Gao and Zhaohui Qin
This research was conducted to quantitatively evaluate the application effect of the frost-resistant ecological substrate in the rock slope of the hydropower station. Field sampling and laboratory tests were conducted to determine the erosion resistance and fertility of frost-resistant ecological substrate, and the test results were compared with those of natural soils with similar site conditions. The research conclusions were as follows. Compared with the natural soil, the content of > 0.25 mm mechanical-stable aggregates, > 0.25 mm water-stable aggregates, average weight diameter, geometric average diameter, organic matter, available nitrogen, available phosphorus, and available potassium of frost-resistant ecological substrate, significantly increased. On the contrary, erodibility factor, percentage aggregate disruption, aggregate degree, and dispersion rate decreased evidently. These results showed that erosion resistance and fertility of the frost-resistant ecological substrate have a better prospect in the engineering application of alpine regions. In addition, the principal component analysis showed that the principal component value of frost-resistant ecological substrate increased by 1.9 times that of natural soil. According to the correlation study, the increase in the amount of > 0.25 mm macro-aggregates and organic matter is the primary reason that ecological substrate has greater stability and fertility than natural soil. In conclusion, the frost-resistant ecological substrate was a suitable soil to create a suitable vegetation growth environment on the surface of rock slope in the alpine region.
Afficher plus [+] Moins [-]Analysis and Evaluation on Characteristics of Heavy Metal Pollution in the Coastal Farmland Soil along the Wuma River Texte intégral
2021
Xiongfei Cai, Die Xu, Shijie Zhao, Li Lei, Ji Wang and Bin Xuan
The thesis is aimed to provide a reference for the sustainable utilization of farmland soils along the Wuma River, an upstream tributary of the Chishui River in Guizhou Province. Geo accumulation index method, Nemero comprehensive pollution index method, and potential ecological hazard index method were used based on the experimental data for analyzing and evaluating the heavy metal pollution status of farmland soil along Wuma River. The results showed that: (1) The contents of heavy metals Ni, Cu, Zn, Pb and Hg in farmland soil exceeded the soil background values of 9.82%, 47.80%, 13.72% and 76.06% in Guizhou Province, respectively, but did not exceed the standard limit class II based on the environmental quality. (2). The pollutants of Pb and Zn in the research area mainly come from mineral exploitation, waste residue accumulation, and transportation. The enrichment of Cr and Cu may originate from the domestic garbage dumping and incinerated waste by residents along the coast and irrational agricultural activities. The main contents of Cd, As and Hg come from soil geochemistry. (3) The ranking of accumulations of eight heavy metals was IPb>IHg>ICu>INi>IZn>ICr>IAs>ICd, among which Pb was non-moderately polluted and the remaining heavy metals were at the clean level; Nemero comprehensive pollution index showed that As, Cr, Zn, and Ni were mildly polluted, while Pb, Hg, and Cu were moderately polluted. The ranking of potential ecological risk levels for the eight heavy metals was Hg, Pb, Cu, Ni, As, Cd, Cr, Zn. The overall ecological risk level is mild.
Afficher plus [+] Moins [-]Study on the Electrochemical Anticorrosion Effect of Piezoelectric Materials in the Internal Environment of Water Supply Pipeline Texte intégral
2021
T. Li, G. Li, X. Zhang, S. Xu and H. Ghougassian
The problem of corrosion in water supply pipelines not only poses a considerable threat to the safety of drinking water but also causes a large amount of water wastage due to the leakage of the pipeline network, which can be a chronic problem for a municipal water supply system, as observed in Beijing and other cities in China. In this study, a new piezoelectric PVDF fiber membrane was prepared by electrospinning process, and a piezoelectric anticorrosive film was fabricated based on the internal environment of the pipeline. In the simulated water supply pipeline environment, based on the principle of the piezoelectric effect and the principle of cathodic protection, the electrochemical corrosion protection effect of piezoelectric materials in the water supply pipeline environment, under different water quality conditions, was investigated by a single factor experiment. The results show that piezoelectric anti-corrosion tablets have an obvious inhibitory effect on pipeline corrosion under different pH values, ammonium nitrate concentrations, chloride ion concentrations, and sulfate ion concentrations. Furthermore, under the conditions of pH neutral, alkaline, and high ion concentration, the piezoelectric anti-corrosion sheet can protect the pipeline by 100%. Additionally, since the piezoelectric material can convert mechanical energy into electrical energy and does not cause pollution during the experiment, it has good environmental and economic benefits. The use of piezoelectric materials for preventing corrosion of pipelines is a frontier exploration. We believe that the improvement and development of material properties, and the combination of these new materials and traditional techniques, will provide new ideas and methods for pipeline anti-corrosion technology.
Afficher plus [+] Moins [-]An Empirical Research on Pig Farmers’ Adoption Behaviours of Waste Disposal Texte intégral
2021
Wenjie Yao and Liguo Zhang
Based on the field survey data of 608 pig farmers in Zhejiang Province, this paper carries out empirical analysis on pig farmers’ current adoption behaviours of waste disposal and its influencing factors and the change of pig farmers’ waste disposal behaviour intention caused by the implementation of environmental subsidy and its influencing factors. The research shows that the implementation of environmental subsidy has a great impact on the willingness of pig farmers to change their waste disposal behaviours, and they will be more inclined to adopt the behaviours that can fully realize the utilization of resources to dispose of their waste. The implementation of environmental subsidy is effective and can encourage pig farmers to change the existing relatively unreasonable and inefficient waste disposal behaviours on the premise that the pig breeding scale, the expected net income from waste disposal, the knowledge of waste reduction methods, the willingness of waste disposal training, the awareness of policies to ban and limit pig breeding, the distance between the pig farm and the nearest river and many other factors can be controlled. Therefore, the government should focus on implementing environmental subsidy for waste disposal with high utilization of resources such as biogas technology and composting technology.
Afficher plus [+] Moins [-]Coordination Relationship Between Green Innovation Efficiency and Environmental Protection: Evidence From the Yangtze River Economic Belt Texte intégral
2021
Na Hou, Zhi Zeng, Qianying Zhu, Dahong Zhang and Wenwen Liu
Green innovation plays an important role in coordinating the relationship between ecological environment and economic development and has become a new driving force for the development of a resource-saving and environment-friendly economy. To explore the effects and logic of innovation efficiency and environmental protection, using the inter-provincial (city) panel data of the Yangtze River Economic Belt from 2007 to 2017 in China, the green innovation efficiency and environmental protection level of the upper, middle, and lower reaches of the Yangtze River Economic Belt were analyzed. Results show that the overall environmental protection level of the Yangtze River Economic Belt is on the rise. From a regional perspective, the environmental protection level in the upper reaches is the highest, which is greater than the overall level of the Yangtze River Economic Belt, followed by the lower and middle reaches, which are less than the overall level of the Yangtze River Economic Belt. The efficiency of green innovation has promoted the overall environmental protection level of the Yangtze River Economic Belt, inhibited the environmental protection level in the downstream areas, promoted the environmental protection level in the upstream areas, and has no obvious impact on the environmental protection level in the middle reaches. Further mechanism analysis shows that the possible transmission path of green innovation efficiency to environmental protection is as follows: green innovation efficiency promotes the environmental protection level by improving the ecological environmental efficiency. The robustness of the above conclusion is tested, and it has good robustness. The research conclusions of this study provide reliable empirical evidence and policy enlightenment for the development and optimization of green innovation efficiency and the realization of green innovation efficiency driving environmental protection.
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