Although individuals and corporations alike are making strides to reduce the amount of waste that goes into nation-wide landfills, trash and by-products are still populating landfills. After reuse, recycling, and composting efforts 54% of America’s municipal solid waste meets it’s final destination in a landfill.
While landfill disposal is the least desirable option in the waste management hierarchy, it’s important to know that modern landfills shouldn’t carry the same negative connotations of older versions.
The Modern Landfill vs the Old Dump
So, what is a modern landfill? You may have heard them called municipal solid waste landfills and they are highly regulated and advanced. They are very different than the old-fashioned “dumps” you probably picture when thinking about waste disposal.
In the past, dumps were created very simply, digging a hole in the ground and filling it with trash. Once the trash reached a certain limit, it was burned and then the entire opening was covered with new soil.
Initiated by The Resource Conservation and Recovery Act (RCRA), passed by Congress in 1976, these dumps were overhauled and have become more efficient and environmentally conscious. The RCRA expanded the federal government’s role in managing waste disposal, divided waste into non-hazardous and hazardous categories, and developed design and operational standards for sanitary landfills.
In today’s municipal solid waste landfills we see evidence of advanced regulation and sustainability efforts in the following improvements:
- Locations & Operations
- Better Designs
- Environmental Protection
- Reclamation & Reuse
Problems Addressed by This New Landfill Design
Many of the environmental concerns attributed to landfills of the past have been addressed and eliminated as modern landfill techniques began to be used.
1. Unsafe and Inappropriate Locations
Prior to RCRA regulation, dumps were potentially created on any large, unused space with little concern for its impact on the surrounding areas. Waste was compacted each day and covered with soil to reduce odor and contamination. New landfills, however, take into consideration the health of individuals and the environment. Today’s landfills cannot be constructed near floodplains, wetlands or fault areas/unstable areas.
2. Groundwater Contamination
Another problem with older landfill design was that waste was deposited directly onto the soil with no barrier or liner. This allowed water (referred to as leachate) to percolate through the waste, pick-up harmful contaminates, and then enter into the soil. Improved landfill design requires that protective liners, made of clay or plastic, provide a barrier between the disposed waste and the ground below. Now any liquid that develops among the waste is collected and treated to prevent contamination.
3. Release of Methane Gases
Methane gas and carbon dioxide, also known as greenhouse gases, are a natural by-product of any landfill, whether old or new. They are created as organic waste matter decomposes. These gases are known to trap and hold heat in the atmosphere, known as the greenhouse effect, and are recognized as being a leading contributor to global warming.
Modern advances in landfill technology have made it possible to minimize the number of greenhouse gases released from landfill waste. Under the Clean Air Act, larger facilities, where gas emissions reach 55 tons per year are required to install a gas collection and destruction system. Additionally, many smaller facilities have voluntarily installed similar systems. When greenhouse gases are captured, they can be destroyed or treated to generate energy sources such as electricity and fuel.
4. Reuse of Space
In the past, when dumps were no longer usable, a final layer of soil was added to the top and, in some instances, vegetation was planted. But often, vegetation couldn’t even grow due to the methane gas and contaminated soil found below and the space was never useable again.
But limited land and growing interest in cultivating community and green space has changed the way that closing landfills are used. Modern landfills are designed from the start for reuse once the landfill closes. Almost indistinguishable from other land, you can now find parks, sports fields, parking lots, commercial space, and even agricultural land thriving over landfill land.
The Future of Modern Landfills
Always looking for a way to implement more sustainable and green practices, the waste industry is developing further enhancements for the future of landfills. This includes the use of bioreactors and biocovers.
Bioreactor landfills add liquid and air to the disposed waste, which in turn accelerates the degradation of the waste. When waste breaks down faster, there is a shortened period of time that greenhouse gases are produced and a quicker turnaround of the land for reuse in the community.
A biocover is created when a facility uses composted yard waste as the final cover for a landfill. Biocovers go even further in reducing the number of greenhouse gases released by waste facilities, as the gases are oxidized and stabilized by the compost.