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Toxic Waste Decomposition: 

Toxic Waste Decomposition Environmental Microbiology By Brian Lee

General Overview: 

General Overview History Significant events The EPA, the Superfund, and the NPL The state of toxic waste in the U.S. today Landfills Incineration Bioremediation

The Beginnings : 

The Beginnings World War II brings an unprecedented growth in the economy and business Breakthroughs in organic chemistry War effort and postwar economic boom Huge volumes of wastes generated by this evolving industry Lack of knowledge on environmental and health ramifications of waste disposal

Results of mismanagement of waste: 

Results of mismanagement of waste Rachel Carson publishes Silent Spring in 1962 Provoked widespread public alarm with her attack on pesticide usage, emphasizing the unintended ecological consequences of pesticide use Illustrated interconnected web of life and how such “elixirs of death” were stored in humans

Contamination Incidents: 

Contamination Incidents Two cases in Japan make worldwide headlines Hundreds paralyzed due to mercury poisoning caused by eating shellfish affected by products of a chemical plant Rash of miscarriages blamed on use of rice-cooking oil contaminated with Poly Chlorinated Biphenyls (PCBs)

Contamination Incidents: 

Contamination Incidents Love Canal, August 1977 Black sludges bleed through basement walls in suburban subdivision of Niagara Falls, NY Reports of benzene fumes in kitchens, headaches, skin problems, respiratory discomfort Shortly, dioxin detection, miscarriages and birth defects Government pays for evacuation, at cost of $30 million

Love Canal, con’t: 

Love Canal, con’t Evacuation process piecemeal over three years amidst climate of high tension, misinformation, broken promises May 19, 1980 – Love Canal activists take two government representatives hostage overnight Caused by one hundred thousand drums of chemical waste dumped into an abandoned canal by Hooker Chemical and Plastics Corporation Shows that some kind of regulation is needed

Government Action: 

Government Action 1970 – Environmental Protection Agency (EPA) formed to give national government a structure coordinate an attack on pollutants which harm human health and degrade the environment 1980 – Congress passes the Comprehensive Environmental Response, Compensation and Liability Act, aka “Superfund” Tax on chemical and petroleum industries Broad federal authority to respond to releases or threatened releases of hazardous wastes


Landfills Majority of waste is deposited in landfills First “sanitary” landfills developed in 1920s Solid wastes are spread out in thin layers, compacted, and covered daily with fresh clay or plastic Solved problem of foul smell and reduced incineration needs But by 1960s, evident that not capable of containing groundwater contamination

Landfills, con’t: 

Landfills, con’t Modern landfills are lined with clay and plastic before being filled with garbage Bottom is covered with a second impermeable liner, usually made of several layers of clay, thick plastic, and sand This liner collects leachate, rainwater contaminated as it percolates through the solid waste, which is then pumped from bottom of the landfill, stored in tanks, and sent to a sewage treatment plant

More on Landfills: 

More on Landfills Anaerobic conditions are created within landfill waste Slow stabilization of waste mass occurs, producing methane Explosive and toxic over long periods of time One study found that aerobic degradation of waste within a landfill can significantly increase the rate of waste decomposition and settlement, decrease production of methane gas, reduce level of toxic organics in leachate, and decrease amount of leachate that need treatment


Bioremediation Biological treatment of hazardous waste Compounds like used oil, battery acid, PCBs, heavy metals, detergents, pesticides, and radioactive wastes are poisonous to us But some microbes use such ‘toxic’ compounds as food

Bioremediation, con’t: 

Bioremediation, con’t Phytoremediation – the use of natural or genetically engineered plants to filter and remove contaminants Clean up soil and water contaminated with pesticides, organic solvents, radioactive metals, and toxic metals such as mercury and lead. Chernobyl disaster (1986) leaves iodine, cesium-137, strontium and plutonium in soil, plants and animals Green plants used to remove toxins from soil

Current Research: 

Current Research Motivation is to look at waste as potential resources Wastewater reclamation by microfiltration and ultraviolet disinfection as an alternative Termites for wood fiber degradation as a means of controlled biodegradation

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