Building on Landfills

This article lists the types of things being built on landfills, and explains the concerns with this practice.

(PRWEB) April 11, 2004 --With the increase in population and subsequent development in many urban areas, the value of land is rising. In many areas, little land is left untouched -- including that on old landfills. Many cities are now looking to utilize this land in a multitude of ways.

Some of the more popular items to be built on old landfills include parks, schools, golf courses, amphitheaters, and even homes. Granted, while many of these additions are beautiful and benefit the community, there are a variety of concerns ranging from the leakage of potentially dangerous methane gas, leachate (leading to contaminated water) and settlement of structures built upon the filled landfill.

Lets take a closer look at each of these concerns and what can be done about them.

Methane Gas
Methane is a result of the decomposition of landfill. Its a natural gas and an energy source but is also considered a greenhouse" gas contributing to the depletion of the ozone layer. Methane is flammable and explosive in certain concentrations so it needs to be controlled. Modern day landfills are designed to vent or somehow use this methane gas.

Some recent problems have resulted from older landfills that were not designed correctly or modern day facilities that, once closed and built over, have not been properly monitored. For instance, In 1999, at an Atlanta playground build on an old landfill, an 8 year old girl was seriously burned when methane gas caused an explosion. Or in 1994 a Charlotte, NC woman was seriously burned by a methane blast while playing soccer in a park built over a landfill. Both cases were from old landfills that were not properly vented to let mounting gas escape.

At Shoreline amphitheater in Menlo Park, CA methane gas is burned through a specially designed venting system. The amphitheater is part of a 750 acre recreational and wildlife area built on an old landfill that is now home to parks, lakes, an estuary and golf course. While this is a good example of proper management, the monitoring of methane can still be a problem. Many times people have no idea that the building they work in or that their child is being taught in is residing on an old dump.

Leachate
Leachate is produced when water derived from solid waste and added water sources such as rain and snow, flows through landfill waste (similar to how water flows through coffee grounds) transporting contaminants from within the landfill. To prevent contamination of groundwater and potentially toxic exposure to outside land sources, a complex combination of liners, filters, monitoring wells and capping of the landfill must be maintained. Constant monitoring must be maintained to ensure the health and safety of the public.

Settlement of Waste
Eventually, waste in our landfills does begin to decompose. As this process occurs, the ground settles and takes up less space causing the ground above to sink. This can result in the sliding of homes from their foundations, significant cracks in walls and damage to plumbing and overall building safety.

Some developers take great care in the restructuring of landfill land by using engineered fill to account for settlement and make the natural process less damaging. Eventually, the land will stabilize, however, there still is the factor of the unknown and this is what poses the greatest concern to this author. What are the long term effects of building on landfills? How will these structures hold up during severe earthquakes? Is there regular testing for the leaching of hazardous chemicals? Is the soil tested on a regular basis for contamination?

Its nearly impossible to test the combinations of chemicals at different levels for each landfill site and its affect on human health. While many of the known chemicals such as benzene are considered non-toxic in small doses, we know nothing of the results when many of these chemicals are mixed together and humans are exposed to them over a period of time.

Building on landfills is, and always will be, of concern. Land is precious and every inch in urban areas will be maximized. One of the most important things that we can do is to minimize the amount of landfills that we create and fill. This all goes back to decreasing our trash. And more importantly, be aware and conscious of what is disposed of in your household trash. All hazardous materials need to be properly disposed of - contact your city if you need locations of local hazardous waste drop-off locations.

You never know, your children may be attending school on top of your household waste. Wouldnt you want to know whats in there?

Written by Val Reddemann ~ President of greenfeet.com

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