Most people think of landfills as dumps. Open holes where garbage is deposited, swarming with vermin and other animals.A landfill is a bit more carefully designed. Usually a hole built into the ground with a bottom liner, isolating garbage from coming into contact with the environment.
Two types of landfills: Sanitary: lined with layers of clay, sand and plastic. Secure: almost same as a sanitary landfill, but with thicker layers of clay and plastic. For dumping hazardous materials (sometimes separated into barrels to prevent mixing of incompatible wastes). Federalregulation restricts building landfills near faults or bodies of water.
Landfills are not compost piles. Buried waste is kept away from moisture and oxygen and therefore is not decomposed easily. After closing, the site and especially the groundwater have to be monitored for up to 30 years. Fresh Kills Landfill: Staten Island, NY
Two categories of solid wastes: Municipal solid waste (~1%): from residences, businesses, etc. Paper, yard wastes, food scraps, plastics, metals, glass. Non-municipal solid waste (~99%): industry, agriculture, mining, oil and gas production. Construction materials, waste water, sludge, pesticide containers.
Daily,the average American produces 4.6 lbs of garbage. Annually, the US produces over 545 million tons of solid waste (both MSW and non-MSW). Not including hazardous industrial waste. Equivalent to 247,000 space shuttles or 2.3 million Boeing 747s.
The US leads the pack in sending 53.4% of its MSW to landfills. China sends 43% of its MSW to landfills. USestimated to have about 10,000 abandoned landfills, but UNEP says there may be as many as 40,000. 6 European countries, combined, estimated to have 55,000 abandoned landfills. About 1,000 or so are active.
Contamination of groundwater. Rainwater percolates through landfills collects at the bottom liner, from where it is piped out. This leachate contains things like dioxin, mercury, and pesticides and can contaminate nearby aquifers. Cracks/breaks in piping or liners. 2008: 82% of surveyed landfills had leaks; 41% had leaks larger than a square foot.
Many older landfills built before stricter regulations were introduced are located near large bodies of water. Resulting ease of dilution of contaminants makes it difficult for monitoring wells to detect initial leaks.
Releasing methane (CH4): 20x more effective greenhouse gas than CO2. Aerobic bacteria quickly deplete any O2 available for decomposition, after which anaerobic bacterial decomposition dominates the overall process. Landfills in the US release ¼th of all CH4. Gas-to-energy: more efficient landfills collect up to 75% of this CH4, but less efficient ones collect a mere 9%.
Incinerators: Most landfills have incinerators that burn a certain portion of the garbage dumped in them. Waste-to-energy: produce steam that generates electricity. Only 0.3% of US power generation. Produces CO2, SO2, various oxides of nitrogen, mercury/other heavy metal compounds and dioxins. Climate change, smog, carcinogens.
Pollution caused by transportation of garbage. Diesel trucks and trains. Nearly 40 toxic substances in diesel exhaust. EPA identifies as potential human carcinogen.
Running out of space to build landfills. Less active landfills, but newer ones more likely to be larger. Also, less than 10-15% of closed landfills get redeveloped. NIMBY syndrome: Many states, like New York and New Jersey, ship their garbage to other states willing to take them. Hazardous materials to sub-Saharan Africa.
http://www.youtube.com/watch?v=mYLsX50 Cj1Y Recycle! Reduces environmental costs of using landfills and incinerators. Reduces demand for natural resources. Pre-consumer and post-consumer recycling. Curbside, drop-off, and recycling centers.
Composting: Recycles organic yard wastes and food scraps. Returns nutrients to soil like in natural systems. Home composters and municipal composting facilities.
Reuse! Paper, plastic bags, bottles, etc. Reduce overall consumption. Use less packaging. Make fewer individual packages. Use less material to produce goods.