Sanitary Landfills Entomb Your Solid Waste Forever

Sanitary landfills are places where solid waste is disposed of, permanently or temporarily. The sanitary modifier indicates that there is an engineered attempt to contain the waste and its impacts to the facility itself, and not to spill over onto adjacent land, the air, or groundwater. This has been the most common method of waste disposal in recent decades in the U.S. and in many other parts of the world as well.

The term landfill may be applied, perhaps inappropriately, also to a transfer station, where garbage trucks temporarily deliver solid waste until it is transferred to the larger facility by truck. A landfill also may be a private facility used by only one or a small group of industries.

Solid waste is spread in layers and compacted soon after it is deposited on the sanitary landfill site, to keep the area of what is known as the daily cell as small as possible. This covering of the cell reduces the amount of vermin attracted to the site. Cells are devised either through digging a trench and filling it, constructing a ramp along which solid waste will be dumped, or setting aside a disposal area within the landfill.

Monitoring wells are dug outside the site so that any groundwater contamination will be identified as it happens.

Landfills often have a useful life of 15 to 20 years, although this varies widely depending on the characteristics of the site, the degree to which waste is compacted, the disposal and recycling habits of the local population, and regulatory requirements. State environmental agencies set the requirements for sanitary landfills in the U.S., although the EPA (U.S. Environmental Protection Agency) sets a minimum standard below which states cannot go.

These facilities also are categorized as either dry landfills, in which the goal is to segregate the waste as much as possible from air; or wet landfills, in which air is allowed and the leachate even recirculated to encourage more decomposition. Most of us have heard various scandals about what was sitting in the landfill and didn't decompose, so it's important to realize that most landfills are dry landfills and not really designed to decompose its contents. The wet landfill is an experimental attempt to make sure that more of the solid waste actually ends up returning to soil.

Locating Sanitary Landfills

Sometimes landfills take advantage of existing pits, such as those resulting from an extraction activity, or valleys. Often, however, the solid waste is simply stacked on the ground, building up a large mound over time. They should be located away from rivers and creeks and in areas where earthquakes are unlikely. Obviously wetlands and habitat supporting endangered species should be avoided, as well as ordinary floodplains. Since birds are attracted to landfills almost regardless of how well operated they are, sanitary landfills are not placed too close to airports.

The transportation network to deliver the solid waste to the site by truck or rail must be robust, and neighbors who might object ideally should be scarce. State and local regulatory authorities also may impact the siting of sanitary landfills.

Understandably, residential neighbors usually are highly opposed, even if only because of increased smelly truck traffic. Noise from compaction and the possibility of rodents and other pests are also problems, along with general fears that the facility will not be operated properly and that health and environmental concerns will surface when it is too late to do anything about them. Therefore the search for alternatives has accelerated.

Alternatives to Sanitary Landfills

Alternatives center around a waste reduction strategy, which at best postpones the time when new sanitary landfills must be constructed in a region. Incineration (burning in a specially designed apparatus) in some form has been a viable alternative for decades, but no one form of incinerator has emerged as the clear leader.

While the visionary claim that we should strive for zero waste is a worthwhile goal, it is unlikely that in the near future waste will be eliminated entirely, through re-use, re-purposing, recycling, and natural decomposition. So some consideration of sanitary landfills is likely to be a factor of urban life and rural regions for some time to come.

However, recycling, including mandatory home pick-up recycling, can make a major dent in the amount of material deposited in the landfill. More effort needs to be expended to make disposal of batteries, computers, televisions, and other electronic components more convenient. Some locations make hazardous waste disposal, including paint, chemicals, gasoline, and the like, relatively easy, and others have only occasional pick-ups or times and places where citizens can deliver their own hazardous waste.

Hazardous or electronic waste is a bad actor in sanitary landfills, for various reasons, and we can only urge our local authorities to be more industrious in assuring that recyclables and hazardous materials don’t wind up in sanitary landfills. And then householders could do much more to compost their waste; almost any organic matter, from yard waste to food scraps to egg shells and fish bones, eventually will decompose into a very nice fertilizer. Find yourself an attractive plastic composter that allows easy and non-manual turning of the material while it disintegrates.

And see our page about construction materials recycling, an exciting area that could reduce the landfill burden substantially.

Reclamation of Sanitary Landfills

Landfills frequently become golf courses or parks after they have been officially closed according to a fairly elaborate set of EPA standards. These include sealing the top with a very dense clay cap and digging a trench around the base to capture any rainwater.

Recently more adventurous land development has occurred on top of former sanitary landfills, including a California office park. However, when buildings are constructed atop a former landfill, methane gas extraction methods must be utilized to assure there is no explosion hazard. So it's unlikely that this trend will gain much in popularity, with the exception of areas where land values and demand for commercial spaces are extremely high.

Sometimes even during the operation of the landfill, one of the two gases commonly generated by sanitary landfills, methane, can tapped as a source of energy. Vertical pipes are sunk into the landfill pit to capture the methane. If it is not converted to electricity, generally it is simply burned off. The second common gas, by the way, is carbon dioxide.

Post-closure monitoring of sanitary landfills is absolutely essential and regulated by law in the U.S.

My advice to neighborhoods is to urge your local authorities to stay conventional, plant it in grass and make a park, agricultural land, or wildlife preserve. But no water features please. And don't drink the water downstream.

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