A new approach for easy synthesis of Bacillus pseudomycoides immobilized polyvinyl alcohol (PVA)/glutaraldehyde (GA) hydrogel for application in a wastewater treatment system is reported. Optimization studies revealed that GA/PVA mass ratio of 0.03 and acidic pH of 2 were required for hydrogel synthesis and eventually for bacterial cell immobilization. The synthesized crosslinked matrix possessed a pore size suitable for microbial cell entrapment while maintaining cell accessibility to external environment for bioremediation. Possible crosslinking and bacterial cell immobilization in the hydrogel were evidenced by FTIR, XRD, and SEM studies, respectively. Further, the extent of crosslinking of GA with PVA was investigated and confirmed by transmittance and permeability experiments. The viability and proliferation of hydrogel embedded cells (after 25 days) was confirmed by confocal fluorescence microscopy which also indicated that acidic pH of polymer solution did not affect the immobilized live cells. B. pseudomycoides immobilized hydrogel were demonstrated to be effective for treatment of municipal wastewater and reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and protein content below the recommended levels. Overall, the results from this bench-scale work show that employing bacteria-embedded PVA/GA hydrogel for the treatment of municipal wastewater yield promising results which should be further explored in pilot/field-scale studies.
Ambient air dust samples were collected from industrial, commercial and residential areas of four metropolitan cities (Delhi, Calcutta, Madras and Cochin) in India, and were analysed for 27 elements (As, Ba, Br, Ce, Co, Cr, Cs, Cu, Eu, Hf, Hg, Fe, Ga, La, Lu, Na, P, Sb, Sc, Se, Sr, Ta, Tb, Th, Rb, Yb and Zn) by Instrumental Neutron Activation Analysis (INAA). Samples were irradiated with thermal neutrons in a nuclear reactor for 1 day and counted by high resolution gamma spectrometry at different intervals. Several environmental standards such as Coal (SRM 1932b); Urban Particulate Matter (SRM 1648) from NIST, USA; Vehicle Exhaust from NIES, Japan; and Soil-5 from IAEA, Vienna were also analysed for quality assurance. The results reveal that the concentrations of several pollutant elements in dust samples from the four cities are highly variable. Wide differences were observed for elemental concentrations of As, Ba, Br, Cu, Cr, Hg, Fe, Sb, Se and Zn and these variations are explained in terms of their possible sources of origin. 相似文献
Owing to accurate future air quality estimates, need for detecting the anomalously high increase in concentration of pollutants cannot be adjourned. Plentiful approaches were proposed in the past to substantially determine the abnormal conditions, but most of the statistical approaches were computationally expensive and ignored the false alarm ratios. Thus, a hybrid of proximity- and clustering-based anomaly detection approaches to identify anomalies in the air quality data is suggested in this work. The Gaussian distribution property of the real-world data set is utilized further to segregate out anomalies. The results depicted twofold advantages of our approach, by efficient extraction of anomalies and with increased accuracy by reducing the number of false alarms. Specifically, the presence of NO2 concentration in air is investigated in this work, considering its constant increase over decades as well as its inevitable health risks. Furthermore, spatiotemporal segments with anomalously high NO2 concentrations for 14 residential, industrial, and commercial areas of five cities in India are extracted. To validate the results, a comparative analysis with existing approaches of anomaly detection and with two benchmark data sets is performed. Results showed that our method outperformed the existing methods of anomaly detection, when evaluated over metrics such as sensitivity, miss rate, and false alarms. Further, a detailed analysis of extracted anomalies and a detailed discussion about the factors responsible for such anomalies are presented in this work. This study is helpful in educating government and people about spatiotemporal, geographical, and economic conditions responsible for anomalously high NO2 concentrations in air.
Implications: Using our methodology, days with extremely high concentration of any pollutant in air, at any particular location, can be extracted. The reasons for such extremely high pollutant concentration on particular days of a year can be studied and preventive measures can be taken by the government. Thus, by identification of causes of anomalies, future similar events can be avoided. This would also help in people’s decision making in case such events occur in the future. 相似文献
Measurements of temperature, salinity, dissolved oxygen, nitrogen as ammonia, nitrate and nitrite, and phosphate along with chlorophyll were carried out at three stations on the coastal waters of Cochin, south west India, at two-levels of the water column over a period of five years. The data set has been factorised using principal component analysis (PCA) for extracting linear relationships existing among a set of variables. A graphical display of the scores generated from the PCA was done by means of boxplots and biplots, which helped in the interpretation of the data. The major factors conditioning the system are related to the input of fresh water from the estuary of the Periyar river and the high organic load of the bottom sediment in the coastal area which results in a reducing environment, as reflected in the parameters of dissolved oxygen, ammoniacal-nitrogen and nitrite-nitrogen. Another factor which contributes to the variation in the system is related to the unloading activity in the port area. The present approach presents a logical way to interpret the complex data of the physico-chemical measurements. 相似文献
Personal cooling garments (PCGs) have gained increased attention in recent years due to heat stress and strain in the working environment. The present study was conducted in hot environments of an iron foundry to evaluate the efficacy of a battery-operated PCG. Twenty-four workers were exposed to climatic conditions of 35.89?±?1.25?°C, 35% relative humidity during 90-min work with PCG and habitual clothing (HC). Mean weighted skin temperature was significantly lower by 4.84?±?1.05?°C compared with HC 0.38?±?1.02?°C (p?0.05). A statistically significant difference was also observed for 0.492?±?0.26?g mean sweat loss in the PCG group compared with 0.775?±?0.42?g in the HC group (p?0.05). Heart rate, and back and chest skin temperatures were comparatively more reduced in the PCG group compared with the HC group. PCG provides a practical and economical way of alleviating the physiological effects of heat stress when environmental control is not feasible. 相似文献
We propose, discuss and validate a theoretical and numerical framework for sediment-laden, open-channel flows which is based
on the two-fluid-model (TFM) equations of motion. The framework models involve mass and momentum equations for both phases
(sediment and water) including the interactive forces of drag, lift, virtual mass and turbulent dispersion. The developed
framework is composed by the complete two-fluid model (CTFM), a partial two-fluid model (PTFM), and a standard sediment-transport
model (SSTM). Within the umbrella of the Reynolds-Averaged Navier-Stokes (RANS) equations, we apply K–ε type closures (standard and extended) to account for the turbulence in the carrier phase (water). We present the results
of numerical computations undertaken by integrating the differential equations over control volumes. We address several issues
of the theoretical models, especially those related to coupling between the two phases, interaction forces, turbulence closure
and turbulent diffusivities. We compare simulation results with various recent experimental datasets for mean flow variables
of the carrier as well as, for the first time, mean flow of the disperse phase and turbulence statistics. We show that most
models analyzed in this paper predict the velocity of the carrier phase and that of the disperse phase within 10% of error.
We also show that the PTFM provides better predictions of the distribution of sediment in the wall-normal direction as opposed
to the standard Rousean profile, and that the CTFM is by no means superior to the PTFM for dilute mixtures. We additionally
report and discuss the values of the Schmidt number found to improve the agreement between predictions of the distribution
of suspended sediment and the experimental data. 相似文献
Crop losses due to bacterial pathogens are a major global concern. Most of the available pesticides for these pathogens suffer from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and environmental hazards. To overcome these drawbacks, the present study was undertaken to find a potent bactericide. Therefore, a series of compounds comprising bioactive furyl and oxazolone rings was synthesized under microwave irradiation and screened for in vitro antibacterial activity. The reactions were completed in fewer than 2 minutes with minimal use of solvents and resulted in high yields. These compounds were screened for antibacterial activity against plant pathogens, Xanthomonas oryzae, Ralstonia solanacearum and nitrifying bacteria, Nitrosomonas species under laboratory conditions. Five compounds were active as antibacterial agents against Xanthomonas oryzae and Ralstonia solanacearum. However, all compounds were effective against the Nitrosomonas species and the best one was 2-furyl-4-(3-methoxy-4-hydroxybenzylidene)-5(4H)-oxazolone. The study revealed the fast and environmentally friendly synthesis of bioactive title compounds, which also hold promise to be used as prototypes for the discovery of potent analogues. 相似文献
India is the first country to introduce environmental legislation in the constitution but because of lengthy legal procedures,
it is very difficult to control environmental deterioration. There are many factors responsible for this deterioration. Coal
mining is one such activity where deterioration is very severe and the present communication aims this aspect. Coal is the
one of the most essential mineral having large reserves in India. It’s mining and beneficiation produce a variety of pollutants.
The main pollutants emitted during the processing of coal are green house gases, coal dust and acid mine drainage. Many reports
on different aspects of coal mining are available including reports on emission of different pollutants but the present work
is probably only of it’s kind in which the authors have tried to determine environment liability directly in terms of economy.
It was found that greenhouse liabilities, coal dust liability and sulphur liability are accounted for 12.07, 5.0 and 101.97
US$, making an overall 2.4% of the total economic gains due to coal mining. During the calculations approximate number of
total workers and other parameters have been taken into consideration. Who pays for this irreversible damage is a question.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
Industrial waste is one of the main causes of environmental pollution. Laser-induced breakdown spectroscopy (LIBS) was applied to detect the toxic metals in the sludge of industrial waste water. Sludge on filter paper was obtained after filtering the collected waste water samples from different sections of a water treatment plant situated in an industrial area of Kanpur City. The LIBS spectra of the sludge samples were recorded in the spectral range of 200 to 500 nm by focusing the laser light on sludge. Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique was used for the quantitative measurement of toxic elements such as Cr and Pb present in the sample. We also used the traditional calibration curve approach to quantify these elements. The results obtained from CF-LIBS are in good agreement with the results from the calibration curve approach. Thus, our results demonstrate that CF-LIBS is an appropriate technique for quantitative analysis where reference/standard samples are not available to make the calibration curve. The results of the present experiment are alarming to the people living nearby areas of industrial activities, as the concentrations of toxic elements are quite high compared to the admissible limits of these substances. 相似文献