外文翻译----固体废物填埋对环境的影响-环境工程(编辑修改稿)

外文翻译----固体废物填埋对环境的影响-环境工程(编辑修改稿)内容摘要：

tion stage and the rate of gas generation, and the nature of microbial populations within the waste, amongst other factors. Although many odorous trace pounds may be toxic, they have historically been perceived more as an environmental nuisance than as a direct health hazard (Young and Parker, 1984。 Young and Heasman, 1985). The extent to which odors spread away from the landfill boundaries depends primarily on weather conditions (wind, temperature, pressure, humidity). Leachate occurrence is by far the most significant threat to ground water. Once it reaches the bottom of the landfill or an impermeable layer within the landfill, leachate either travels laterally to a point where it discharges to the ground’s surface as a seep, or it will move through the base of the landfill and into the subsurface formations. Depending upon the nature of these formations and in the absence of a leachate collection system, leachate has reportedly been associated with the contamination of aquifers underlying landfills which resulted in extensive investigations for the past four decades (Zanoni, 1972。 Walls, 1975。 Dunlap et al., 1976。 Kelly, 1976。 MacFarlane et al., 1983。 Cheremissinoff et al., 1984。 Reinhard et al., 1984。 Ostendorf et al., 1984。 Mackay et al., 1985。 Albaiges et al., 1986。 Mann and Schmadeke, 1986). In fact, it is speculated that in the .,contamination by municipal landfills, to which every household contributes more than a gallon of hazardous wastes per year (Lee et al.,1986), could bee a bigger problem than contamination associated with the sole disposal of hazardous wastes in landfills (Senior, 1990). Currently, it is estimated that over 25% of the Superfund sites listed on the National Priority List are solid waste landfills (Arigala et al., 1995). Although methane and carbon dioxide are the two major ponents of the gas emitted from landfills, there is evidence that this gas contains numerous other constituents in trace amounts significant enough to cause environmental and health concerns(Lytwynyshyn et al., 1982。 Young and Parker, 1983。 Karimi, 1983。 Gianti et al., 1984。 Harkov et al., 1985。 Todd and Propper, 1985。 Young and Heasman, 1985。 Wood and Porter, 1986。 Rettenberg, 1984, 1987). Potential emissions of Volatile Organic Compounds (VOCs) from landfills can range from 410−4 to 110−3 kg/m2 /day (US EPA, 1989). Atmospheric gas emission rates through a landfill cover have been measured by several investigators. During dry soil conditions at a semiarid landfill site, Bogner et al. (1989) indicated that methane and carbon dioxide fluxes may be as high as 630 and 950 kg/ m2/yr, respectively. Using flux box measurements, Lytwynyshyn et al. (1982) and Kunz and Lu (1979, 1980), estimated that methane diffusion flux through landfill covers ranged between 390 and 1200 kg/m2/yr. These measurements are likely to underestimate actual emission rates because of aerobic oxidation of methane near the surface by methanotrophs. Although emission rates from controlled experiments may not be representative of actual emissions from landfills, they clearly demonstrate the propensity of gas release into the atmosphere. 5. Landfill gas and leachate control Landfill gas control measures are essential in order to eliminate or minimize its associated adverse environmental impacts. In most cases the installation of a gas recovery, collection and treatment system will assist in preventing gas migration away from the landfill boundaries or gas emissions through the landfill surface. Indeed many of the early gas recovery projects were developed as a consequence of, or as an adjunct to, existing gas migration control schemes. When landfill gas is recovered appropriately its methane content represents an energy reservoir of great potential. It is estimated that annual gas generation potential in the US alone exceeds 6 billion m3 (Dawson, 1981。 Marchant,1981). The energy represented by this gas could meet 1% of the total energy needs or5% of the natural gas utilization in the . (Lytwynyshyn et al., 1982). Reported estimates of worldwide annual gas generation potential vary widely, 30 to 430 billion m3 (Bingemer and Crutzen, 1987。 Lagerkvist, 1987。 Dessanti and Peter, 1984。 Sheppard et al., 1982). The upper range is questionable, particularly when pared with methane yield data from actual landfills with a recovery system. The economic feasibility of landfill gas recovery, processing, and utilization have indeed been demonstrated and reported by many investigators at sites under different climatic conditions (Boyle, 1976。 Lockman, 1979。 Kaszynski et al., 1981。 EMCON, 1983。 Mouton, 1984。 Wiqwist, 1986。 Gendebien et al., 1992). New landfills can be designed to prevent landfill gas accumulation even if no productive use of the gas is planned. Landfill gas control systems have been well documented in engineering practice (Wei。