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Comparative Study on the Treatment of Landfill Leachate by Coagulation and Electrocoagulation Processes 全文
2019
C. Ramprasad, Karthik Sona, Mohammed Afridhi, Ram Kumar and Naveenatha Gopalakrishnan
Landfill leachate is a complex mixture of organic and inorganic compounds and their concentration level highly depends on the type of waste dumped, age of the landfill, etc. Last few decades, the researchers are exploring the feasibility of treating landfill leachate using physicochemical, biological, advanced processes and combination of these methods. The current study focused on the comparison of two commonly adopted technologies for landfill leachate treatment, chemical coagulation/flocculation and electrocoagulation process. The leachate samples were collected from two different places and examined for the following parameters: pH, turbidity, chemical oxygen demand, chlorides, alkalinity, hardness, solids and nutrients. The current study focused on studying the effect of different inorganic coagulants (alum and ferric chloride), coagulant dosages, different electrode material (titanium coated with platinum/stainless steel and aluminium/stainless steel), electrolysis time and current intensity on the removal of pollutants from leachate and reuse for non-potable applications. The raw leachates collected from the two sites were found to be significantly different in their characteristics due to the age of landfill and physiognomies of wastes dumped. The batch treatment studies showed that both the treatment systems are nearly displaying a similar kind of removal efficiency (more than 74%). Amongst that, the coagulation/flocculation process showed a better removal efficiency and cost effectiveness compared to electrocoagulation process. Additionally, the treated water was found to be not meeting the Indian Standard for inland disposal. Therefore, an additional post treatment like reed bed process or sand filtration will be a viable option for non-potable applications.
显示更多 [+] 显示较少 [-]Pollution Evaluation of a Phosphorus-Rich Area of Zhongxiang City 全文
2019
Miao Song
An extensive survey was carried out to understand the spatial distribution and possible sources of soil heavy metals in a phosphorus-rich area. A total of 615 topsoil samples were gathered, utilizing a regular sampling grid of 1×1 km squares, and the contents of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), vanadium (V) and zinc (Zn) were analysed to investigate the spatial distribution of these heavy metals, identify their sources, and assess levels of pollution. The results showed that the enrichment factor (EF) of the studied metals decreased in the order Cd > As > Pb > Co > Ni > Cr = Cu > Zn, and the mean contents of Cd, As and Pb were significantly higher than the background values. According to potential ecological risk (RI), 11.2% of the study areas had considerable potential ecological risk and the other areas had low to moderate potential ecological risk. The results of multivariate and geostatistical analyses indicated that Co, Cr, Ni and V, and to a lesser extent Cu and Zn, mostly originated from natural sources; while As and Pb, and to a lesser extent Cd, Cu and Zn, mainly originated from phosphorus-related industrial activities. The results also showed that Cd was affected by water with Cd pollution from the Hanjiang River. These results are useful for establishing policies for protecting local soil quality.
显示更多 [+] 显示较少 [-]Mutagenicity of Bulk, Aqueous and Organic Partitions of Air Particulate Matter in Differentially Ventilated Wards in a Public Urban Hospital 全文
2019
Aurora S. Nakpil, Emmanuel S. Bajaand Paul Mark B. Medina
The hospital environment requires indoor air quality conducive to the recovery of patients with poor health. Low indoor air quality is associated with an increased incidence of respiratory tract diseases and the development of cancer. This study investigated the mutagenicity of air particulate matter soluble in bulk, aqueous, and organic partitions collected from naturally and mechanically ventilated wards in the hospital environment through the Ames test and the mutagenicity testing with the D7 strain of Saccharomyces cerevisae. Bulk, aqueous, and organic fractions of air particulate matter at maximum (100% concentration), 10% concentration, and 1% were found to be mutagenic with both the Ames test (p < 0.05) and mutagenicity testing with D7 strain of S. cerevisae (p < 0.05). The Ames test suggested slight dominance of the aqueous phase-soluble mutagens in naturally ventilated wards (p < 0.05), and a more balanced mix of aqueous and organic phase mutagens in mechanically ventilated wards. Mutagenicity testing with the D7 strain of S. cerevisae showed no significant differences between the naturally and mechanically ventilated wards (p > 0.05), but showed the relative dominance of the organic phase-soluble mutagens over the other fractions (p < 0.05). Few other studies have compared naturally and mechanically ventilated wards through the lens of potential effect on the mutagenic activity of air particulate matter, but more understanding in this area is important in moving towards the development and implementation of policies to optimize ventilation systems for the health and safety of hospital staff and patients. Albeit coming from the study of concentrated air particulate matter samples, the mere presence of these mutagens in the air of the hospital highlights the importance of monitoring their quality and quantity such that they do not become concentrated enough to induce mutation-related etiologies of disease such as cancer.
显示更多 [+] 显示较少 [-]Process Optimization for the Preparation of Activated Coke from Industrial Waste Using Response Surface Methodology 全文
2019
Juanqin Xue, Xiande Jing, Shudi Hu, Yuhong Tian, Yonghui Song and Xinzhe Lan
Fine blue-coke and direct liquefaction residue of coal are byproducts in the process of coal chemical production. They were taken as raw materials for the preparation of activated coke by the activation of carbon dioxide. The conditions (activation temperature, activation time and carbon dioxide flow rate) for activated coke preparation were optimized by response surface methodology (RSM). Results showed that activation temperature and activation time had a significant effect on the activated coke iodine adsorption value. The synergistic effect of activation time and carbon dioxide flow had a great influence on iodine adsorption value of activated coke. RSM optimization experiment obtained the optimum activation conditions were activation temperature of 850°C, activation time of 90min and carbon dioxide flow rate of 60 mL/min. Under these conditions, the obtained activated coke iodine adsorption value can reach 401 mg/g, which could meet the needs of industrial desulphurization.
显示更多 [+] 显示较少 [-]Retrieval of the Canopy Chlorophyll Density of Winter Wheat from Canopy Spectra Using Continuous Wavelet Analysis 全文
2019
Qingkong Cai, Erjun Li, Jiechen Pan and Chao Chen
Continuous wavelet analysis (CWA) has been applied to leaf-scale spectral data for quantifying leaf chlorophyll content, but its application to canopy-scale spectral data for estimating the canopy chlorophyll density (CCD) of winter wheat at different growth stages requires further analysis. This study aims to estimate CCD by applying CWA to the canopy spectra of 185 samples from Guanzhong Plain, China. The five most informative wavelet features related to CCD were identified using the CWA method. Meanwhile, 10 commonly used spectral indices were selected to compare with the CWA method. Two partial least square regression (PLSR) models based on wavelet features and spectral indices were developed and compared. Results showed that the PLSR model using wavelet features (R2 = 0.64, RMSE = 0.43 g/m2) was better than that using spectral indices (R2 = 0.57, RMSE = 0.48 g/m2) and wavelet features were less sensitive to the growth stage variation than spectral indices. This result suggested that the CWA approach can derive robust wavelet features and was more effective than spectral indices for predicting CCD from canopy-scale spectral data for an agricultural ecosystem.
显示更多 [+] 显示较少 [-]Influence of Tourism Industry Development on Environmental Pollution and EcoCompensation Measures in Chongqing City, China 全文
2019
Jixia Zhou
Ecological environment is not only the basis for human survival and development but also the carrier of tourism industry development. However, such a basis for survival and development of the tourism industry is damaged given the excessive pursuit of economic benefits and neglect of ecological environmental protection in tourist attractions. Eco-compensation measures protect the tourism ecosystem and coordinate the contradiction between tourism industry development and ecological protection. Thus, the sustainable development of the tourism industry can be facilitated. In this study, research on environmental pollution caused by the tourism industry in Chongqing City, China, and relevant eco-compensation measures were first reviewed. Second, an empirical study on the relations of total tourism revenues with waste gas emission, wastewater discharge, and industrial solid waste emission in Chongqing City was conducted using a vector autoregression model. The study findings show that tourism industry development can influence environmental pollution slightly and that an eco-compensation mechanism coordinates the relationship between tourism and ecological environment. Tourism economic growth has long-term equilibrium relations and mutual Granger causality with waste gas emission, wastewater discharge, and industrial solid waste emissions. The conclusions provide a reference to understand the dynamic relations between tourism industry development and environmental pollution, construct a guarantee system for tourism eco-compensation mechanism, and achieve sustainable development of tourism industry and environmental protection.
显示更多 [+] 显示较少 [-]Heavy Metal Accumulation in Some Fishes Preferred for Consumption by Egrets in Odisha, India 全文
2019
Bibhu Prasad Panda, Biswajit Panda, Siba Prasad Parida, Biswajita Mahapatra, Aditya Kishore Dash and Abanti Pradhan
The reduction of wetlands due to the increase of urbanization and industrialization has been an emerging global concern and is a threat to the fish population. Fishes have been proved as excellent indicators of heavy metal contamination of the aquatic ecosystems. The present research aims to determine the metal accumulation in fishes of different wetlands. Fish samples were collected for analysis of different metals like lead (Pb), chromium (Cr), copper (Cu) and zinc (Zn) by atomic absorption spectrophotometer. Pb concentration varies from 0.41-44.33 µg/g and found to be highest at Hirakud, whereas Cr, Cu and Zn were highest at Koraput which vary from 1.3-10.36 µg/g, 1.29-4.17 µg/g and 20.97-54.99 µg/g, respectively.
显示更多 [+] 显示较少 [-]Biomonitoring of Water Bodies in Metro Manila, Philippines Using Heavy Metal Analysis and Erythrocyte Micronucleus Assay in Nile Tilapia (Oreochromis niloticus) 全文
2019
Zeba F. Alam, Charilen Kei V. Concepcion, Johnray D. Abdulrahman and Miguel Alvaro S. Sanchez
Environmental biomonitoring of water bodies is routinely done to assess the ecological state of aquatic systems by detecting the hazardous and genotoxic pollutants. In this study, a combination of atomic absorption spectroscopy and the fish micronucleus assay was used to determine and compare the genotoxic potential of water bodies specifically the two Esteros namely, Estero de Vitas and Estero de Paco, which are part of the Pasig River System, Philippines. As part of the strategy, the Esteros are being rehabilitated to control pollution in the river systems whereby Estero de Paco was recently rehabilitated, whereas, Estero de Vitas is still largely neglected. The elevated levels of micronuclei and nuclear abnormalities were observed in the erythrocytes of the genetic model, the Nile tilapia (Oreochromis niloticus) exposed to water samples from the two sources tested when compared to a control group indicating the presence of genotoxic and hazardous pollutants in the water bodies of Estero de Paco and Estero de Vitas. Further, the water samples from Estero de Vitas were found to be far more genotoxic as compared to the water samples from Estero de Paco (p<0.05). The observed genotoxic effects of the water samples appeared to be related to the physico-chemical characteristics studied using atomic absorption spectroscopy, which showed the presence of heavy metals in the water samples from both the sources. The AAS results also confirm the presence of heavy metals in the fish tissue exposed to the water samples from the two locations. Hence, the tilapia fish (a component of Filipino diet) should be consumed with precautions as it can absorb the heavy metals present in ecosystems. The results establish that the fish micronucleus test is an effective assay for environmental biomonitoring. The lower genotoxicity potential of Estero de Paco clearly demonstrates that the restoration of the Esteros can be an effective approach to control pollution of the water bodies, especially the Pasig river system.
显示更多 [+] 显示较少 [-]Vertical Distribution of Microplastics in Coastal Sediments of Bama Resort, Baluran National Park, Indonesia 全文
2019
Muhammad A. Asadi, Yody A.P. Ritonga, Defri Yona and Asus M.S. Hertika
Microplastic pollution is widely reported in different marine environments from shorelines to seabed of deep seas which pose an emerging threat to entire marine ecosystems. As the world’s secondlargest microplastics polluter, an understanding of the distribution of this type of pollution is important for the measurement of the magnitude of environmental risk. In the present study, the abundance and distribution of microplastics in coastal sediments of Bama Resort, Baluran National Park were measured at depths of 0-10 cm, 10-20 cm, and 20-30 cm. Microplastics characterization was performed using a modified flotation method while a sieve analysis was used to assess the particle size of the sediments. Results showed that there were 484 particles with a total average abundance of 116.41 ± 80.78 particles kg-1 DW. Fibres shared 37.8% of the total microplastics found with overall average of 43.71 ± 36.52 particles kg-1 DW. Overall, Tukey’s multiple comparisons test showed significant differences (P< 0.01) in vertical distribution of microplastics in which 55.46% of particles were found at the depths of 0-10 cm, whereas at the depths of 20-30 cm, the proportion was only 15.95%. There were two types of sediments, sandy gravel and gravelly sand in which the former type of sediments holds higher microplastic particles due to its grain dominance in upper sediments. These results imply that microplastics pollute coastal sediments of Bama Resorts, BNP, and their deposition increase over time as greater microplastics frequencies were observed in upper and more recent sediment.
显示更多 [+] 显示较少 [-]Estimation of Wood Residues Generation from Sawmilling Activities and Energy Potential in Kwara State, Nigeria 全文
2019
E. A. Alhassan, J. O. Olaoye, T. A. Adekanye and C. E. Okonkwo
The global concerns about the rise in anthropogenic gases have resulted in alternative clean energy sources. Biomass is one of the most prominent renewable energy sources, which can be found in wood and wood wastes, agricultural crops and their waste byproducts, municipal solid waste (MSW), animal wastes, food processing, aquatic plants and algae. Wood and by-products obtained from forest biomass stand at the centre of Renewable Energy Source (RES) due to its availability and usefulness in most developing countries. Sawdust is one of the wood processing residues that is in excess of local demand because of the near absence of its industrial demand in Kwara State. Data relating to its availability, industrial usage and energy potential are rarely available in this study area. This study investigates its availability and inherent energy potential that can be a vital tool for energy policy, planning and development. Wood wastes generated in the state were estimated to be 8012.8 m3/yr with inherent energy potential of 31298 GJ. By putting sawdust, seen as wastes in most wood processing plants, into efficient use will help reduce the competition for wood as a source of heat for cooking and heating.
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