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1.
Kimpo metropolitan landfill has received various kinds of wastessince January 1992. The leachate level was measured to be 10.3 m in May 1995 and the level increased to 12.2 m in August 1996. Therefore, to prove the reason for the increasing leachate level, we calibrated hydraulic conductivity of each waste andintermediate layer using the HELP (Hydrologic Evaluation ofLandfill Performance) model. The leachate generation data measured from February 1993 to October 1995 was used in the model calibration. As a result of a model calibration, we obtained anaverage infiltration ratio and used this in analysis of the total water balance to predict elevation of leachate level. Main causes of the elevation of the leachate level were the high water content of the waste and the degradation of the leachate-drainage system caused by the subsidence of a naturalbarrier layer. 相似文献
2.
Assessment of Pb uptake, translocation and immobilization in kenaf (Hibiscus
cannabinus L.) for phytoremediation of sand tailings 总被引:1,自引:0,他引:1
The potential of kenaf (Hibiscus cannabinus L.) for phytoremediation of lead (Pb) on sand tailings was investigated.A pot experiment employing factorial design with two main effects of fertilizer and lead was conducted in a nursery using sand tailings from an ex-tin mine as the growing medium.Results showed that Pb was found in the root,stem,and seed capsule of kenaf but not in the leaf.Application of organic fertilizer promoted greater biomass yield as well as higher accumulation capacity of Pb.In Pb-spike... 相似文献
3.
Daniel S. Cohan Bonyoung Koo Greg Yarwood 《Atmospheric environment (Oxford, England : 1994)》2010,44(26):3101-3109
Air quality models rely upon simplified photochemical mechanisms to efficiently represent the thousands of chemical species that interact to form air pollution. Uncertainties in the chemical reaction rate constants and photolysis frequencies that comprise those mechanisms can generate uncertainty in the estimation of pollutant concentrations and their responsiveness to emission controls. A high-order sensitivity analysis technique is applied to quantify the extent to which reaction rate uncertainties influence estimates of ozone concentrations and their sensitivities to precursor emissions during an air pollution episode in Houston, Texas. Several reactions were found to have much larger proportional effects on ozone’s sensitivities to emissions than on its concentrations. In particular, uncertainties in photolysis frequencies and in the rate of reaction between NO2 and OH to form nitric acid can significantly influence the magnitude and sign of peak ozone sensitivity to nitrogen oxide (NOx) emissions. Ozone sensitivity to VOCs exhibits a much more muted response to uncertainties in the reaction rate constants and photolysis frequencies considered here. The results indicate the importance of accurate reaction rate constants to predicting the ozone impacts resulting from NOx emission controls. 相似文献
4.
Bonyoung Koo Chao-Jung Chien Gail Tonnesen Ralph Morris Jeremiah Johnson Tanarit Sakulyanontvittaya Piti Piyachaturawat Greg Yarwood 《Atmospheric environment (Oxford, England : 1994)》2010,44(19):2372-2382
Natural emissions adopted in current regional air quality modeling are updated to better describe natural background ozone and PM concentrations for North America. The revised natural emissions include organosulfur from the ocean, NO from lightning, sea salt, biogenic secondary organic aerosol (SOA) precursors, and pre-industrial levels of background methane. The model algorithm for SOA formation was also revised. Natural background ozone concentrations increase by up to 4 ppb in annual average over the southeastern US and Gulf of Mexico due to added NO from lightning while the revised biogenic emissions produced less ozone in the central and western US. Natural PM2.5 concentrations generally increased with the revised natural emissions. Future year (2018) simulations were conducted for several anthropogenic emission reduction scenarios to assess the impact of the revised natural emissions on anthropogenic emission control strategies. Overall, the revised natural emissions did not significantly alter the ozone responses to the emissions reductions in 2018. With revised natural emissions, ozone concentrations were slightly less sensitive to reducing NOx in the southeastern US than with the current natural emissions due to higher NO from lightning. The revised natural emissions have little impact on modeled PM2.5 responses to anthropogenic emission reductions. However, there are substantial uncertainties in current representations of natural sources in air quality models and we recommend that further study is needed to refine these representations. 相似文献
5.
Effects of organic amendments on the reduction and phytoavailability of chromate in mineral soil 总被引:9,自引:0,他引:9
In this study, seven organic amendments (biosolid compost, farm yard manure, fish manure, horse manure, spent mushroom, pig manure, and poultry manure) were investigated for their effects on the reduction of hexavalent chromium [chromate, Cr(VI)] in a mineral soil (Manawatu sandy soil) low in organic matter content. Addition of organic amendments enhanced the rate of reduction of Cr(VI) to Cr(III) in the soil. At the same level of total organic carbon addition, there was a significant difference in the extent of Cr(VI) reduction among the soils treated with organic amendments. There was, however, a significant positive linear relationship between the extent of Cr(VI) reduction and the amount of dissolved organic carbon in the soil. The effect of biosolid compost on the uptake of Cr(VI) from the soil, treated with various levels of Cr(VI) (0-1200 mg Cr kg(-1) soil), was examined with mustard (Brassica juncea L.) plants. Increasing addition of Cr(VI) increased Cr concentration in plants, resulting in decreased plant growth (i.e., phytotoxicity). Addition of the biosolid compost was effective in reducing the phytotoxicity of Cr(VI). The redistribution of Cr(VI) in various soil components was evaluated by a sequential fractionation scheme. In the unamended soil, the concentration of Cr was higher in the organic-bound, oxide-bound, and residual fractions than in the soluble and exchangeable fractions. Addition of organic amendments also decreased the concentration of the soluble and exchangeable fractions but especially increased the organic-bound fraction in soil. 相似文献
6.
Design and operating parameters, and cause and effect relationships among feedstocks and products in the pyrolysis of waste polymers are needed if this method of processing is to be used for energy recovery from waste plastics. The purpose of this study was to quantify the effect of various operating factors for the pyrolysis of common polymeric wastes. Experiments were performed using a conventional retort tube as a batch reactor. The operating factors considered were temperature and reaction time at constant heating rate. High density polyethylene (PE) and polystyrene (PS), the most common plastic waste in Korea, were used singly and in mixture.The pyrolysis time for maximum oil production from a PE-PS mixture was shorter than in the case of PE alone, showing an enhancement effect from the PS. The maximum gas production time from PE-PS mixtures was shorter than for PE alone at 500° C; above 600° C, this does not occur. Small aromatic compounds (which can be valuable) are produced at maximum with an 1:1 mixture of PE and PS at 600° C, showing the possibility of process control for the maximum recovery of desirable pyrolysis products. The maximum yield of toluene, xylene, styrene, and 1-propenyl benzene were 8.6, 8.9, 51.0 and 7.4 wt.% of feed for pyrolysis PS at 700° C, respectively. For naphthalene, it was at 700° C with 1:1 PE:PS (by wt.). The maximum recovery was 1.3 wt.%. Diels-Alder theory can explain the formation of aromatic compounds in the pyrolysis products. The yield of these secondary pyrolysis products can be controlled by reaction time, pyrolysis temperature and mixing ratio of plastic wastes in the pyrolysis feed. 相似文献
7.
Morris R Koo B Yarwood G 《Journal of the Air & Waste Management Association (1995)》2005,55(11):1683-1693
Version 4.10s of the comprehensive air-quality model with extensions (CAMx) photochemical grid model has been developed, which includes two options for representing particulate matter (PM) size distribution: (1) a two-section representation that consists of fine (PM2.5) and coarse (PM2.5-10) modes that has no interactions between the sections and assumes all of the secondary PM is fine; and (2) a multisectional representation that divides the PM size distribution into N sections (e.g., N = 10) and simulates the mass transfer between sections because of coagulation, accumulation, evaporation, and other processes. The model was applied to Southern California using the two-section and multisection representation of PM size distribution, and we found that allowing secondary PM to grow into the coarse mode had a substantial effect on PM concentration estimates. CAMx was then applied to the Western United States for the 1996 annual period with a 36-km grid resolution using both the two-section and multisection PM representation. The Community Multiscale Air Quality (CMAQ) and Regional Modeling for Aerosol and Deposition (REMSAD) models were also applied to the 1996 annual period. Similar model performance was exhibited by the four models across the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Clean Air Status and Trends Network monitoring networks. All four of the models exhibited fairly low annual bias for secondary PM sulfate and nitrate but with a winter overestimation and summer underestimation bias. The CAMx multisectional model estimated that coarse mode secondary sulfate and nitrate typically contribute <10% of the total sulfate and nitrate when averaged across the more rural IMPROVE monitoring network. 相似文献
8.
Miao Tian Heekwang Koo Qinwen Xu Jun Li 《International journal of occupational safety and ergonomics》2013,19(1):118-126
Effects of work boots and load carriage (6.4?kg and 12.8?kg) on gait pattern were investigated. The protective work boots were examined by comparison with running shoes through human performance tests with 15 male participants. The loads were carried symmetrically and asymmetrically on the shoulder and hand. Statistical data analysis showed a prolonged stance phase and decreased double support for work boots. A significantly increased ground reaction force was found in work boot conditions as the weight of loads increases. This study demonstrates that inflexible and heavy work boots restrict foot movement and require greater torque at the ankle to propel the body forward, which may increase physical strain and the risk of musculoskeletal injuries. Development of improved fixation methods for work boots, increased use of flexible protective layers and further study of anthropometry of human foot morphology for improved safety and work efficiency of industry workers are suggested. 相似文献
9.
Yus Donald Chaniago Jae-Kyeong Kim Myung-Jun Park Kee-Kahb Koo Moonyong Lee 《Journal of Material Cycles and Waste Management》2016,18(2):366-376
Currently, waste photoresist stripper from the semiconductor industries is generally incinerated at high temperatures or processed as a high-calorie fuel, which can have adverse effects on the environment and economy. Recovery of valuable solvents from waste photoresist strippers is, therefore, very important for thin flat transistor-liquid crystal display (TFT-LCD) manufactures to reduce the production costs and protect the environment against industrial waste. In the present work, systematic laboratory-scale distillation experiments were carried out to regenerate the organic solvents from the waste photoresist stripper and determine if they are feasible to recycle for commercial TFT-LCD grade chemicals: in particular, 1-hydroxyethylpiperazine and methyl diglycol were mainly tried to retrieve. Based on the experiment results, possible alternative distillation sequences were examined through intensive techno-economic analysis using a rigorous process simulator. As a result, an optimal distillation sequence and condition were drawn to separate valuable organic solvents from waste photoresist stripper for a commercial purpose recovery process. 相似文献
10.
Whole effluent toxicity (WET) tests, with Daphnia magna and Selenastrum capricornutum, were introduced to evaluate the biological toxicities of effluents from the wastewater treatment plants (WWTPs) in Korea.
In WET tests of WWTPs effluents, 33.3% (33/99) for D. magna and 92.6% (75/81) for S. capricornutum revealed greater than 1 toxic unit (TU), even though all the treatment plants investigated were operating in compliance with
the regulations, as assessed using conventional monitoring methods (i.e., BOD and total concentration of N or P, etc). There
were only minor differences in toxicities according to the types of influents (municipal and agro-industrial) in all treatment
plants. However, the effluents treated by an activated sludge treatment process were found to exhibit significantly lower
toxicity than those treated by rotating biological contactor (RBC) and extended aeration processes. The seasonal variations
in the toxicity were lower in the summer compared to winter, which may have been due to the rainfall received to the sewage
intake system during the former period. The impact of WET on river water was also investigated based on the discharge volume.
At sites A and B, the total impact of toxicity to stream and river waters was observed to be 70.9% and 90.4% for D. magna and S. capricornutum, respectively. The other four small treatment plants (sites F, G, H and I), with relative discharging volumes between 0.001
and 0.002, contribute less than 1% to the total toxicity. 相似文献