21st CENTURY LANDFILLS
What is a landfill?
Landfill - A carefully designed structure built into or on top of the ground in which trash is isolated from the surrounding environment, such as groundwater, air, and rain. This isolation is accomplished with a bottom liner and daily covering of soil.
* Sanitary landfill - landfill that uses a clay liner to isolate the trash from the environment
* Municipal solid waste (MSW) landfill - uses a synthetic (plastic) liner to isolate the trash from the environment
The purpose of a landfill is to bury the trash in such a way that it will be isolated from groundwater, will be kept dry and will not be in contact with air. Under these conditions, trash will not decompose much. A landfill is not like a compost pile, where the purpose is to bury trash in such a way that it will decompose quickly.
21ST CENTURY LANDFILLS
Today’s landfills are very different from the old ones where people just dumped their garbage in an open area. Landfills are constructed and operated to strict environmental standards, including liners to protect groundwater. Within this hierarchy, landfills are the last of the various solid waste management options that should be considered.
Waste-to-Energy facilities accept solid waste and combust it at very high temperatures producing heat that is used to convert water into steam. The steam is used to run turbines to generate electricity. Scrubbers, filters, and other pollution control equipment reduce pollutants released during the incineration process. Ash and other residues are landfilled.
Yet another way technology is working to make more efficient use of landfills, a gas-to-energy-plant uses the methane gas that is excreted from a landfill as an alternative energy source. Methane gas is one part of "landfill gas" that is produced as a by-product of the airtight decomposition of trash in a landfill, the other part being carbon dioxide. Traditionally, the methane gas is piped out of the landfill and burned off in a "flare." However, with a gas-to-energy-plant, one can use this excess in a productive way. For more information, visit: covanta.comand enviaenergy.com
The Oklahoma Experience Of:
Public Sector Services
5600 NW 4th Street
Oklahoma City, OK 73127
21st Century Landfills: Where Sustainability Meets Waste
If you are of the baby-boom era, as a large portion of the population is today, you probably remember the one time you visited the local landfill and still refer to it as the “city dump.” However, if you’re from a younger generation who now visits modern landfills to enjoy the wildlife habitats or to tour the gas to electricity plants there, you see a much different picture that better illustrates 21st Century landfills.
Today’s modern disposal facilities employ the latest advances in landfill technology. From selecting landfill locations to capping facilities that have been filled to capacity, every effort is made to ensure each site’s operational integrity as well as the safety of the surrounding ecosystems.
Liners form the primary barrier between the landfill’s content and the surrounding environment. State-of-the-art composite liners are made from both synthetic and natural materials. The exact composition of these liners depends on the nature of the waste that will occupy the landfill itself. Most liners include a high-density polyethylene(HDPE) geomembrane over a layer of recompacted welded by hand. Each seam is inspected and tested to prevent leaks. Quality control managers oversee every step of the liner construction.
MODERN LEACHATE COLLECTION AND TREATMENT SYSTEMS
Leachate is the term given to liquids that percolate through landfill waste. Modern leachate collection and treatment systems ensure leachate is captured, removed from the landfill and properly treated to prevent contamination of the surrounding environment.
The modern landfill of today has a custom-designed Leachate control system that takes into account:
• Environmental protection regulations
• Leachate composition
• Local climate
• Site age
• Site operations
• Waste type
Leachate may be treated at community wastewater treatment plants, or engineers may design on-site treatment facilities that use a combination of technologies, including:
• Air stripping
• Biological treatment
• Carbon absorption
• Chemical treatment
In some cases, collected Leachate is reintroduced into the landfill to help speed organic decomposition. In bioreactor landfills, Leachate issued to promote the growth of microorganisms and accelerate the breakdown of organic waste materials.
Choosing the Right Location
A successful landfill begins with the right location. The landfill must not only be convenient to the market it is designed to serve, but must also be constructed on a site that is physically and geologically conducive to permanent waste disposal.
Surveyors, engineers and designers employ the latest in computer imaging and CAD technology to:
• Scout potential landfill locations
• Perform comprehensive geological surveys
• Develop landfill designs that work harmoniously with the local environment
• Create physical and operational safeguards to protect local ecosystems
LANDFILL GAS COLLECTION AND MONITORING
Just as Leachate must be collected and processed to keep a landfill functioning properly, so must gases produced by organic decomposition –primarily methane and carbon dioxide – be collected and controlled.
Advanced gas monitoring equipment is available to ensure landfill gas emissions do not exceed EPA regulations. In addition, many landfills have been specially designed to collect landfill gas for use as an alternative energy source. Landfill gas powers over 1 million homes across the United States. In Tulsa, OK, the Quarry Landfill partners with LaFarge International and the methane collected replaces 15% ofthe fossil fuels they formerly used to power their kilns to make concrete. In Oklahoma City, OK, East Oak Landfill participated in a pilot program to create diesel and equipment lubricants from the methane produced by the decomposing garbage, and is now a Gas-to-Liquids Plant.
To ensure the integrity of the surrounding environment, permanent groundwater monitoring stations are installed. Groundwater well placement and design standards should be in accordance with the American Society of Testing and Materials (ASTM) and include the use of numerous components.
FINAL COVERS GIVE FORMER LANDFILLS LONG-TERM LIFE
Sooner or later, all landfills reach their capacity. However, that doesn’t mean it’s the end of their useful life. By “capping” landfills with synthetic membranes, clay and topsoil, closed disposal sites can be converted into beneficial community assets. Many closed landfills become:
• Natural Preserves
• Golf Courses
• Baseball fields
• Recreational facilities
• Community common grounds
Continuous, long-term monitoring of groundwater and Leachate conditions protect the environment and ensure the integrity of capped landfills for decades to come.
Ultimately, however, one of our long-term goals should be to keep as much material as possible out of landfills. What better way to do this than to follow the three “Rs”—Reduce, Reuse and Recycle.
Top Ten Things We Can Do To Make A Difference
1. Know what’s recyclable in your community. Usually, it includes:
a. Paper: newspapers, phonebooks, mail, office papers, school papers, boxes,
catalogs, and magazines. For every household that recycles it's daily
newspaper, 5 trees are spared each year!
b. Plastic beverage & food containers
c. Aluminum and Tin beverage & food containers. Did you know that 34.8
billion aluminum cans are thrown away annually?
2. Look for recycled or recyclable symbols on things you buy.
3. Save H2O! Turn off the water while you’re washing your hands. Rinse only under the water.
4. Save Energy! Turn off the lights when you leave a room. Also, keep bulbs dust free. Dust can reduce light emission by 10%
5. Use rechargeable batteries. Americans use about 2 billion disposable batteries a year. Using a set of rechargeable batteries will help keep toxins out of landfills, and can save you up to $2,000 in the long run since you can reuse them hundreds of times.
6. Wash clothes the cool way – Washing clothes in hot water uses 15x more energy than cold.
7. Don’t buy spray cans that contain CFC (chlorinated fluorocarbons).
8. Use the car less and carpool more.
9. Be “tote-ally” conscientious – Plastic bags kill about 1,000,000 birds and 100,000 sea mammals every year. So, when you shop, bring along a reusable tote bag(s) for your shopping.
10. Let your P.C. take a nap. Those screen saving fish swimming across your monitor are wasting energy. To keep them alive, your monitor runs on full power. So try sleep-mode: it uses hardly any electricity.
Sustainability means a world ……
• Where clean, alternative ways to produce power exist, forever putting to rest the threat of exhausting our natural resources.
• Where “reduce, reuse and recycle” becomes the slogan of every family and organization in Oklahoma..
• Where companies take a leadership position by investing in cleaner technologies so that air pollution is eliminated.
• Where the environment is respected and every day actions are aimed at recovery and restoration.
• Where stewardship of the environment is paramount.