Presentation on theme: "ESC110 Chapter Thirteen Solid and Hazardous Waste."— Presentation transcript:
ESC110 Chapter Thirteen Solid and Hazardous Waste
Chapter Thirteen Readings & Objectives Required Readings Cunningham & Cunningham Chapter 13: Solid & Hazardous Waste At the end of this lesson, you should be able to: identify the major components of the waste stream, and describe how wastes have been - and are being - deposited in North America and around the world. explain the differences between dumps, sanitary landfills, and modern, secure landfills. summarize the benefits, problems, and potential of recycling and reusing wastes. analyze some alternatives for reducing the waste we generate. understand what hazardous and toxic wastes are and how we dispose of them. evaluate the options for hazardous-waste management. outline some ways we can destroy or permanently store hazardous wastes.
Chapter Thirteen Topics Waste Waste-Disposal Methods Shrinking the Waste Stream Hazardous and Toxic Wastes
PART 1: WASTE Agricultural waste (50%) Residues produced by mining and primary metal processing (30%) Industrial waste million metric tons/year (3.6%) with a large toxic/hazardous part! Municipal waste million metric tons/year (1.8%) or 2 kg/person/day. The United States produces 11 billion tons of solid waste each year.
Composition of U.S. Domestic Waste
The Waste Stream Waste stream is the steady flow of varied wastes we all produce. In spite of recent progress in recycling, many recyclable materials end up in the trash. A major problem is refuse mixing where recyclable and nonrecyclable materials, hazardous and nonhazardous materials are mixed and crushed together is the collection process.
PART 2: WASTE DISPOSAL METHODS Low to High Preferences of Waste Disposal Are: Open Dumps Ocean Dumping Landfills Exporting Waste Incineration
Open dumping is a predominant method of waste disposal in developing countries. Illegal dumping classifies as a type of open dumping. Groundwater contamination is one of the many problems with open dumping. Open Dumps
Sanitary Landfills Landfills control and regulate solid waste disposal with less smell, litter and vermin Refuse compacted and covered everyday with a layer of dirt. Dirt takes up as much as 20% of landfill space. Since 1994, all operating landfills in the US have been required to control hazardous substances. More than 1,200 of the 1,500 existing landfills in the U.S. have closed, and many major cities must export their trash.
Exporting Waste and “Garbage Imperialism” Although most industrialized nations in the world have agreed to stop shipping hazardous and toxic waste to less developed countries, the practice still continues. Within rich nations, poor neighborhoods and minority populations are more likely to be the recipients of Locally Unwanted Land Use (LULUs). Toxic wastes are sometimes “recycled” as building materials, fertilizer or soil amendments.
Incineration and Resource Recovery Incineration is burning refuse to reduce disposal volume by 80-90%. Energy recovery is possible through heat derived from incineration. Steam from this process can be used for heating buildings or generating electricity. Refuse-derived fuel is when waste is sorted to remove recyclable and unburnable materials. This yields refuse with a higher energy content than raw trash. Mass burn means everything smaller than major furniture and appliances is loaded into furnace. It results in greater problems with air pollution. Residual ash has toxic components including dioxins. High construction costs and environmental regulations have resulted in closures and waste exportation.
Mass-Burn Garbage Incinerator Initial construction costs are usually between $100 and $300 million for a typical municipal facility. Tipping fess are often much higher at incinerators than tipping fees at landfills.
PART 3: SHRINKING THE WASTE STREAM Reduce, Reuse and Recycle (the 3 R's) Reusing is a wash & refill process unlike recycling. Recycling success stars are aluminum & auto batteries. Problems include fluctuating market prices & contamination. Recycling is better than dumping or burning. Recycling is the reprocessing of discarded material into new, useful products.
Recycling Benefits –Saves money, raw materials, and land. –Encourages individual responsibility. –Reduces pressure on disposal systems. Japan (an island nation short on land) recycles about half of all household and commercial wastes. –Lowers demand for raw resources. –Reduces energy consumption and air pollution. Benefits Example –Recycling 1 ton of aluminum saves 4 tons of bauxite, 700 kg of coke and pitch, and keeps 35 kg of aluminum fluoride out of the air. –Producing aluminum from scrap instead of bauxite ore cuts energy use by 95%.
Municipal Waste, 1995
Source Separation in the Kitchen
U.S. Recycling Rates
U.S. Recycled Materials
Ways Other Than Recycling to Shrink the Waste Stream Composting is the biological degradation of organic material under aerobic conditions. Energy can be obtained from waste. Demanufacturing is the disassembly and recycling of obsolete consumer products such as computers & household appliances. Reuse is exemplified each time you clean a bottle and drink from it again. A reusable glass container makes an average of 15 round-trips between factory and customer before it has to be recycled. Generating less waste by not consuming originally or using more compostable and degradable packaging.
Shrinking the Waste Stream Excess packaging of food and consumer products is one of our greatest sources of unnecessary waste. Paper, plastic, glass, and metal packaging material make up 50% of domestic trash by volume. Producing less waste Some environmentalists think that society currently places too much emphasis on recycling, thus ignoring better solutions such as reduced consumption and reuse.
Demanufacturing Demanufacturing is the disassembly and recycling of obsolete consumer products Refrigerators and air conditioners produce CFC's. The CFC's can be recycled, thus avoiding their release too the environment. Computers and other electronics produce both toxic and valuable metals A problem is that electronics that are turned in for recycling in the U.S. are sometimes dumped in developing countries where their components end up as environmental toxins.
Reuse Better than recycling or composting. Salvage from old houses is an increasingly popular trend in construction. Glass and plastic bottle potential for reuse is poorly realized. Large national companies favor recycling over reuse.
Producing Less Waste Reduction in consumption is the best way to reduce our waste stream. Excess packaging of food and consumer products is one of our greatest sources of unnecessary waste. Photodegradable plastics break down when exposed to UV rays. Biodegradable plastics can be decomposed by microorganisms. There are problems with photodegradable and biodegradable plastics.
PART 4: HAZARDOUS AND TOXIC WASTES Hazardous wastes are discarded solids or liquids with substances that are fatal in low concentrations, toxic, carcinogenic, mutagenic or teratogenic. This includes corrosive, explosive, reactive and flammable materials. U.S. industries generate about about 265 million metric tons of officially classified toxic wastes each year. Chemical and petroleum industries are the biggest sources of toxins
U.S. Hazardous Waste Producers
Hazardous Waste Disposal Legislation Resource Conservation and Recovery Act (RCRA) Comprehensive program requiring rigorous testing and management of toxic and hazardous substances with cradle to grave accounting. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund Act) Superfund Amendments and Reauthorization Act (SARA) created a Toxic Release Inventory. The act requires manufacturing facilities to report annually on releases of hundreds of types of toxins.
Tracking Toxic and Hazardous Wastes
Superfund Sites EPA estimates 36,000 seriously contaminated sites in the U.S. and by 2000, 1,551 sites were placed on the National Priority List for cleanup with with Superfund financing. Superfund is a revolving pool designed to: Provide immediate response to emergency situations posing imminent hazards. Clean-up abandoned or inactive sites.
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). –Modified in 1984 by Superfund Amendments and Reauthorization Act. Aimed at rapid containment, cleanup, or remediation of abandoned toxic waste sites. –Toxic Release Inventory - Requires >20,000 manufacturing facilities to report annually on releases of more than 300 toxic materials. In order to act the government does not have to prove anyone violated a law, or what role they played in a superfund site. –Liability under CERCLA is “strict, joint, and several”, meaning anyone associated with a site can be held responsible for the entire clean-up cost.
National Priority List (NPL) & Brownfields EPA estimate: 36,000 seriously contaminated sites in the U.S. General Accounting Office (GAO) estimates that there are > 400,000 seriously contaminated sites NPL sites are waste sites that are especially hazardous to human health or environmental quality How clean is clean? Brownfields are large areas of contaminated properties that have lost their potential value. Because of the presence of assumed pollutants, the areas are considered liability risks. This business attitude discourages redevelopment and can be >30% of the land within urban areas. In many cases, property owners complain that unreasonably high purity levels are demanded in remediation programs.
Options for Hazardous Waste Management Produce less waste using 3 R's Physical treatments (isolation) Incineration Chemical processing (transformation Bioremediation (microorganisms) Permanent retrievable storage Secure landfills
When Hazardous Waste Management Options To Cleanup Fail, Storage Is Required Ways to Store Permanently are: –Retrievable Storage Can be inspected and periodically retrieved. –Secure Landfills Modern, complex landfills with multiple liners and other impervious layers and monitoring systems. To guard and monitor these sites for leakage is very costly.