landfill



THE LANDFILLS INFRASTRUCTURE

What is the largest construction you can think of? Does a landfill come to your mind? Probably not. One of the largest buildings on the face of the earth is the Pyramid of the sun, constructed in Mexico and covers approximately thirty million cubic feet of space. Now if you think that is big just imagine an even larger structure: a landfill that occupies over seventy million cubic feet of biosphere, we are talking about the Durham Road landfill, outside San Francisco. It is a sad monument, indeed, to the excesses of modern society [Gore 151].

One might assume such a monstrous mound of garbage is the largest thing ever produced by human hands. Unhappily, this is not the case. The Fresh Kills Landfill, located on Staten Island, is the largest landfill in the world. It sports an elevation of 155 feet, an estimated mass of 100 million tons, and a volume of 2.9 billion cubic feet. In total acreage, it is equal to 16,000 baseball diamonds [Miller 526]. By the year 2005, when the landfill is projected to close, its elevation will reach 505 feet above sea level, making it the highest point along the Eastern Seaboard, Florida to Maine. At that height, the mound will constitute a hazard to air traffic at Newark airport [Rathje 3-4].

A modern state-of-the-art sanitary landfill is a graveyard for garbage, where deposited wastes are compacted, spread in thin layers, and covered daily with clay or synthetic foam. In a landfill there are four major sections: The bottom liner (layers of clay or synthetic flexible membrane), a leachate collections system (collection of badly contaminated water from landfills), a cover (it is an "umbrella" that covers the landfill preventing water to get inside), and the natural hydrogeologic system (the actual terrain surrounding the landfill). The modern landfill is covered with impermeable layers of clay, sand, and plastic before any garbage is put into it. This liner prevents liquids, called leachates, from going into the groundwater. Leachates result from rainwater mixing with fluids in the garbage, making a highly toxic "juice" containing inks, heavy metals, and other poisonous compounds. Ideally, leachates are pumped up from collection points along the bottom of the landfill and they are sent to liquid waste disposal points or put back into the upper layers of garbage, to resume the cycle. The aim is to avoid any hydraulic (water-related) connection between the wastes and the surrounding environment, particularly groundwater [The basic of landfills]. Unfortunately, most landfills have no such pumping system [Miller 527]. Until the formation of the Environmental Protection Agency by Nixon in 1970, there were almost no regulations on the construction, operation, and closure of landfills. As a result, 85 percent of all landfills existing in this country are unlined (covered with impermeable layer). Many are located in close proximity to aquifers or other groundwater features, or near geologically unstable sites. Many older landfills are leaching toxins into our water supply at this very moment, with no way to stop them. For example, the Fresh Kills landfill leaks an estimated one million gallons of toxic ooze into the surrounding water table every day [Miller 527].

Pros and Cons
Sanitary landfills do offer certain advantages. The daily cover of clay or other material dramatically reduces offensive odors, the mainstay of the old city dump. Vermin and insects, both of the terrestrial and airborne varieties, are denied a free meal and the opportunity to spread disease, by the daily clay layer. Furthermore, modern landfills are less of an eyesore than their counterparts of yore.

Nevertheless there are more disadvantages in this system, although we have to take into consideration that without this structures, god knows where would all this garbage be floating. The daily compacting and covering of the garbage deposits effectively squeezes the available oxygen out of the material. Whatever aerobic bacteria are present in the garbage can not survive for very long and so decomposition stops. Anaerobic bacteria, by their very nature, are not present in appreciable numbers in our biosphere. What few manage to enter and survive in the garbage deposits are slow-acting and perform little in the way of breaking down the materials. In other words, rather than the giant compost heap