【正文】 環(huán)境和健康問題。從壓力對流講，從高壓力區(qū)向低壓區(qū)遷移。在垃圾填埋環(huán)境下，從后者往往是受到限制的。例如，近 80在美國產(chǎn)生的危險廢物都是填埋處置的。EMCON, 1983。 Wood and Porter, 1986。 Walls, 1975。 Mosey, 1983。 Gendebien et al., 1992). Alternatives to landfilling are considered as volume reduction processes because they produce waste fractions ( and slag from bustion processes that represent the second leading method of waste disposal) which ultimately must be landfilled (Emberton and Parker, 1987). Resorting to landfills is not limited to the disposal of municipal solid waste, but it icludes most other industrial wastes. For instance, nearly 80% of hazardous wastes generated in the . is dumped in landfills (Eichenberger et al., 1978). Solid waste position varies substantially with socioeconomic conditions, location, Most organic materials are biodegredable and can be broken down into simpler pounds by aerobic and anaerobic microorganisms, leading to the formation of gas and leachate. The following sections provide an overview of the mechanisms of gas and leachate formation in land?lls, their environmental impacts, and appropriate control methods to eliminate or minimize these impacts. 2. Land?ll Gas Formation Mechanisms At the time of waste deposition in a land?ll, oxygen is present in the void space, giving rise to aerobic deposition during which biodegradable organic materials react quickly with oxygen to form carbon dioxide, water, and other byproducts (. bacterialcells). Carbon dioxide is produced in approximate molar equivalents to the oxygenconsumed. Oxygen depletion within the land?ll marks the onset of the anaerobic depositon phase. Although a land?ll ecosystem undergoes an initial short aerobicdeposition phase, the subsequent anaerobic phase is the dominant phase in its age and the more important one from the perspective of gas formation. Much of what is known or assumed concerning anaerobic processes in land?lls has primarily e from work with anaerobic digesters. Microbial populations in both environments appear to be similar however, the major di?erence is that the substrates may vary in their relative content of fat, protein, and carbohydrates, and conversely to land?lls, the environment in anaerobic digesters is well controlled and often under optimal conditions. Investigators have recognized several major steps to describe the anaerobic deposition phase during which organic materials are converted to methane and carbon dioxide (Alexander, 1971。 Leone and Flower, 1982。 Karimi, 1983。 Gendebien et al., 1992). New land?lls can be designed to prevent land?ll gas accumulation even if no productive use of the gas is planned. Land?ll gas control systems have been well documented in engineering practice (Weiss, 1974。本文對填埋氣體，堆填區(qū)滲濾液的形成機理和對環(huán)境造成不良影響做了概述，并介紹了消除或減少這些影響的方法。 一般而言，有機質(zhì)在厭氧生態(tài)系統(tǒng)的分解按順序從復雜到稍微復雜的顆粒物質(zhì)水解開始到更復雜的高分子蛋白質(zhì)，碳水化合物和脂肪 ， 進一步水解產(chǎn)生如氨基酸，糖，高分子脂肪酸。 4．環(huán)境影響 從歷史上看 ，垃圾填埋 的實施 ， 主要是為了保護環(huán)境和社會，減輕其他垃圾處理方法的不利影響，例如露天焚燒，露天傾倒和海洋傾倒。在何種程度上遷移到堆填區(qū)邊界以外，主要取決于天氣條件（風，溫度，壓力，濕度）。填埋氣體回收適當?shù)募淄楹?，是對潛力巨大的能源。特定處理工藝選擇將取決于滲濾液質(zhì)量和數(shù)量。 通過在有限范圍內(nèi)密切監(jiān)測和分析填埋垃圾可以控制滲瀝液的組成。雖然從控制實驗的排放率不是從垃圾填埋場實際排放量的代表，但是它們清楚地表明了氣體釋放到大氣中的傾向。 臭氣味 氣味，主要是將（在垃圾填埋氣體的酯，硫化氫，有機物，烷基苯，檸檬烯 和其他碳氫化合物，）排放到空氣。由于微生物的活動也可能有助于滲濾液形成，但 是 量很少。雖然經(jīng)歷了一個垃圾填埋場生態(tài)系統(tǒng)短期好氧分解的初步階段，隨后的厭氧階段在持續(xù) 的 時間 和 氣體形成的角度 看 是主要的反應階段 。 2. numerical simulation. Water Resources Research, 21,1–26. Adamse, A. D., Hoeks, J., DeBont, J. A. M. and Kessel, J. F. (1972). Microbial activities in soil near natural gas leaks. Archiv fur Microbiologie, 83, 32–51. Albaiges, J., Casado, F. and Ventura, F. (1986). Organic indicators of groundwater pollution by a sanitary land?ll. Water Research, 20, 1153–1159. Alexnder, M. (1971). Microbial ecology. New York: John Wiley amp。 Kaszynski et al., 1981。 Mackay et al., 1985。 Parker and Williams, 1981。 Rushbrook, 1983。 Pohland et al., 1983。 Cheremissino? et al., 1984。 Dessanti and Peter, 1984。 Shen et al., 1990). In addition to gas recovery and active gas pumping, control measures include: (1) the installation of impermeable barriers before site operations to secure the perimeter of the land?ll (cement walls, clay trenches, impervious liner materials such as plastics, rubber, asphalt, polyvinyl chloride, high density polyethylene, etc.)。 2． 填埋氣體的形成機理 在填埋廢物分解的過程中，產(chǎn)生氧氣，導致可降解有機物迅速與氧氣發(fā)生反應，形成形成二氧化碳，水和其他的產(chǎn)物。 3．滲濾液形成機制 滲濾液形成 是 可溶性物質(zhì)在垃圾中以水的形式不均勻和間歇滲透的結果。損害發(fā)生主要是由于填埋氣 體對植物根部氧氣的直接替換而導致的缺氧。在一個半干旱填埋場 干燥的土壤條件，使用通量箱測量， Bogner 指出，甲烷和二氧化碳通量可高達630 和 950 公斤高 / m2/yr。 （ 2）被動式排氣 在填埋場邊界設置一個盲溝，在背部用粗料如礫石（回填）創(chuàng)建一個將被氣體優(yōu)先使用的高滲透率區(qū)域。填埋氣體的遷移和滲濾污水向堆填區(qū)邊界的外移和以及對周圍環(huán)境釋放是目前新的嚴重環(huán)境問題，包括潛在的健康危害，火災，爆炸，破壞植被，臭氣，垃圾填埋場沉降設施，地下水污染，空氣污染和全球變暖。全球每年的天然氣發(fā)電潛力估計 是 很大的， 30至 4300 千萬 立方米 ， 但 在與有回收系統(tǒng)的實際填埋場的甲烷產(chǎn)量數(shù)據(jù)進行了對比后上限是有質(zhì)疑的。這取決于材料的性質(zhì)，滲濾液收集系統(tǒng)的有無，過去 40 年的廣泛調(diào)查的結果發(fā)現(xiàn) ， 滲濾液與堆填區(qū)底部的含水層接觸 ，會 導致含水層的污染。 4． 1 火災和爆炸危險 雖然垃圾填埋氣甲烷回收是能源恢復的一個機會，它往往被 認為是不利的，由于其易燃性，它能與空氣形成爆炸性混合物，其有水平和垂直遷移的傾向而擴散 到 堆填區(qū)邊界以外。醋酸分解形成甲烷和二氧化碳。事實上