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1.
The biowaste fractions in municipal solid waste (MSW) are the main odor sources in landfill and cause widespread complaints from residents. The ammonia (NH3) and hydrogen sulfide (H2S) generation processes were simulated and compared between four typical biowaste fractions individually and combined in the mixed MSW. Food waste was found to be the main contributor to odor emission in mixed MSW, with H2S generation potential of 48.4 μg kg?1 and NH3 generation potential of 4742 μg kg?1. Fruit waste was another source for NH3 generation, with 3933 μg kg?1 NH3 generation potential. Meanwhile, nitrogen (N) was released in a faster way than sulfur (S) in waste, since 31% and 46% of total NH3 and H2S were generated in the first 90 days after disposal, with 1811 and 72 μg kg?1, and more emphasis should be placed in this initial period.

Implications:?Monitoring of odor generation from biowastes in MSW on a laboratory scale showed that food waste is the main source for NH3 and H2S generation, whereas waste fruit is another main contributor for NH3 released. Generally, N was released in a faster way than S from mixed-waste landfilling.  相似文献   

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A method for setting air quality standards for long-term cumulative exposures of a population based on epidemiological studies has been developed. It uses exposure estimates interpolated from monitoring stations to zip code centroids, each month applied to zip code by month residence histories of the population. Two alternative cumulative exposure indices are used—hours in excess of a threshold, and the sum of concentrations above a threshold. The indices are then used with multiple logistic regression models for the health outcome data to form dose response curves for relative risk, adjusting for covariates. These curves are useful for determination of at what exposure amounts and threshold levels, effects which have both statistical and public health significance begin to occur. The method is applied to a ten year follow-up of a sub cohort of 7,343 members of the National Cancer Institute-funded Adventist Health Study. Up to 20 years of residence history was available. Analysis for prevalence of symptoms was conducted for four air pollutants— total oxidants, sulfur dioxide, nitrogen dioxide, and total suspended particulates. For each pollutant, cumulated exposures were calculated above each of five different thresholds. Statistically significant effects were noted for total suspended particulates, total oxidants, sulfur dioxide, past and passive smoking.  相似文献   

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ABSTRACT

The kinetics of pentachlorophenol (PCP) ozonation in terms of the gaseous O3 and dissolved PCP concentrations has been investigated. When the O3 concentration in the gas phase was in the range of 10 to 40 g O3/m3, the O3 dissolved for a short time period was proportional to the gaseous O3 concentration. In this range, the ozonation reaction was first order for each reactant and the overall reaction was second order. At 25 °C, in an aqueous solution, the reaction rate constant was estimated to be 10.048 L/mol-sec. The reaction rate was much greater than the mass-transfer rate, indicating that the reaction of O3 and PCP was an interface reaction on the surface of gaseous O3 bubbles. The final product of the PCP ozonation was oxalic acid, with the carbon yield of the reaction being 59.4%. The ozonation of PCP in the aqueous solution was not a radical reaction but a direct reaction between O3 and PCP molecules under the conditions investigated in this study, since O3 has a high selectivity toward PCP. The reaction rate increased with the reaction temperature up to 35 °C but decreased at temperatures greater than 35 °C due to the decreased solubility of O3. The addition of H2O2 did not increase the reaction rate significantly.  相似文献   

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In the April 1989 issue of JAPCA, current information about regulatory agencies at the state and local levels in the United States and at the federal, provincial and local levels in Canada was published. U.S. Environmental Protection Agency appointments at the federal and regional levels had not been completed in time for April publication but are published in this supplement. Also listed are the individuals in the Minerals Management Service of the U.S. Department of Interior who have regulatory responsibility for air pollutant emissions from oil, gas and mineral extraction activities in the Outer Continental Shelf (OCS) areas of the United States.  相似文献   

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Abstract

Clay that contains kaolinite has been used extensively as a raw material for manufacturing of bricks and china at 900–1100 °C. This study used clay to stabilize the contaminant chromium(VI) [Cr(VI)] through a heating process at 500–1100 °C. X-ray absorption spectroscopic results indicated that the 500–900 °C heating process transformed hazardous Cr(VI) to nontoxic Cr(III); Cr2O3 was the species detected as most abundant. The 1100 °C heating process caused the formation of Cr2SiO5, which was not detected in the samples heated at 500–900 °C. Fourier transformed extended X-ray absorption fine structure spectra were fitted by use of WinXAS software. Phase shifts and backscatter(ing) amplitudes for specific atom pairs, based on the crystallographic data for CrO3 and Cr2O3, were theoretically calculated with the FEFF software. The processed XAS data show that the first shell coordination numbers were similar to each other as the temperature was increased from 500 to 900 °C and 1100 °C, implying that their Cr(III) crystallite size was relatively similar. The interatomic distance between the target center element and the first shell for the 500– 1100 °C samples was 1.98Å. The Debye-Waller factor for the 1100 °C sample was increased compared with the 500 and 900 °C samples and probably indicates the formation of Cr2SiO5.  相似文献   

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APCA Is Thriving     
Fiscal nineteen seventy three-four was another busy year for the Association. It was a year of expanded services, publications, and meetings. New initiatives on the part of the Board of Directors, the Technical Council and its committees, local APCA Sections and the Headquarters staff were undertaken. All of the statistical reports are positive, and show increased membership, pages published, advertising, meetings, and involvement of members. But of more importance, APCA is filling its role in a positive and meaningful way, and is continuing to attract persons working in the air pollution control profession to its many programs.

As most of you know by now, dues for individual members have been increased from $25 to $35 annually because of the continued inflation in postage, paper, and cost of doing business.  相似文献   

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On June 5 and 6 of 1980, two parallel plume oxidation studies were carried out in the vicinity of the Tennessee Valley Authority's Colbert Steam Plant. One study was performed in a smog chamber into which stack gases were injected and mixed with ambient air. The other study included direct airborne sampling of the power plant plume. Atmospheric oxidation rates for the conversion of SO2 to SO4 2- and the removal rates of NO x (which is presumably the rate of NO3 - formation) were estimated for both studies. The SO2 to SO4 2- rate coefficients were found to be 0.022 ± 0.009 h-1 for both chamber experiments and the first airborne sampling day. For the second day, a rate constant of 0.041 ± 0.052 h-1 was estimated from the aircraft data. The large deviation in this value is explained by the fact that the plume from the power plant combined and reacted with the urban plume from the city of Florence, AL. The formation of a very large "O3 bulge" on this day is also attributed to the mixed plumes. The first order rate coefficients for NO x removal were estimated to be 0.27 ± 0.14 h-1 for both chamber experiments and the first airborne sampling day. A NO x removal rate could not be determined for the second airborne sampling day.  相似文献   

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The atmospheric, edaphic, and vegetative components of the roadside ecosystem contain elevated levels of lead originating from the combustion of lead containing gasolines by motor vehicles. The size of this ecosystem approximates 3.04 X 107 hectares (118,000 square miles) in the United States. Recent evidence has greatly refined our understanding of the distribution and localization of lead in the roadside environment. This paper is a representative review of some of this recent evidence. Vehicles release approximately 80 mg of lead/km to the atmospheric compartment in the form of inorganic lead salts ranging in size from 1 to 5 µ. Lead content of roadside atmospheres may be elevated 2-20 times non-roadside atmospheres. Sedimentation from the atmospheric compartment results in lead contamination of the soil and vegetative compartments. Lead in the upper 5 cm of the soil profile may be elevated 30 times non-roadside soil within a few m of a street or highway. The soil lead is largely bound by organic matter exchange sites or present as the relatively insoluble lead sulfate. The increased lead burden of plants, largely due to surface deposition, may be 5-20,50-200, and 100-200 times baseline lead levels for unwashed agricultural crops, grass, and trees respectively. Invariably most plant studies demonstrate a strong inverse correlation between plant lead level and sampling distance normal to the highway and a less strong, but direct, correlation between lead burden and traffic volume. While our appreciation of the distribution of lead in the roadside ecosystem is good, our understanding of its chemistry and the effects on the biota are deficient. Acute and direct impacts of lead on components of the roadside biota are not apparent. The potential for interactive effects with other stress factors and for subtle impact is considerable, however, especially in regard to plant surface and soil microbiota, foraging insects and animals, and plant leaf and root metabolism.  相似文献   

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