Chapter 16 - 17

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<p>Slide 1</p> <p>80,000+ tons spilled via broken storm pipe</p> <p>2008: Tennessee dam break spills 1.1 billion gallonsCoal ash spilling into North Carolinas Dan RiverChapter 16Waste DisposalKinds of wasteConventional solidConventional liquidHazardous wasteNuclear waste</p> <p>Solid WastesAgriculture (crops &amp; animals): more than 50%Mineral industry (spoils, tailings, slag, etc)Cities and towns(small amount of municipal waste)Manufacturing (highly toxic)</p> <p>Major source of solid waste in U.S. are:</p> <p>The big onesLandfills</p> <p>Important to control the migration of leachateSites for sanitary landfills are often controversial NIMBY issues</p> <p>Open Dumps unlovely, unhealthy, and unappetizingSanitary Landfills alternate layers of compacted trash and a covering materialBarriers lock in toxins and chemicals, reduce leakage into the environmentCheap when space is availableRecyclingLess volume at the end of the waste stream means less landfill space needed and slower filling of available sites. </p> <p>Treated organic waste can be fed to swine or composted, or even converted to energy onsite or at specialized facilitiesRecycling any reuse of waste reduces volume at landfillsRecover recyclable waste by source separation; separate waste into useful categories</p> <p>Twin Cities recycling rate is still low: 30 50% recovery of the recyclable materialsSaint Paul will see major changes soon: single sort, addition of more types, and curbside composting are all planned for the near future</p> <p>Liquid Waste DisposalStrategies:Dilute and disperseConcentrate and containSecure Landfills Holding tanks or dams commonAlternative is to place in sealed drums with impermeable lining materialDeep wells inject deep into the crustLeachate not containedExpensive and uncertain</p> <p>Ajka, Hungary 2010</p> <p>Aluminum sludge dam breaks, kills 7; pH = &gt;9Sewage Treatment</p> <p>Septic Systems: soil microbes and oxygen complete the breakdown of the organic matterMunicipal Sewage TreatmentPrimary treatment: removal of solids from organic liquid wastebacteria and fungi act to dissolve and breakdown the organic matterfiltration, chlorination, and other chemical treatment may occurWaste-to-energy alternatives can </p> <p>Organic solid waste requires treatmenthazardous wastes</p> <p>Extra steps to contain and stabilize hazardous waste can be expensiveRadioactive WastesEstablished by Nuclear Waste Policy Act of 1982 establish a high-level disposal site in the westCharacteristics:Volcanic host rockArid climate, low regional water tableLow population density (but Las Vegas is 60 miles to the southeast)Apparent geologic stability [??]</p> <p>Enormous and costly legal fight, still no solution but project is near death$ 40,000,000,000</p> <p>Radioactive Decay unstable nuclei decay and produce lots of energy constant rateRadioisotopes each have their own rate of decay measured in a half-life 30 years about contaminated groundwater</p> <p>State alerts Minneapolis neighborhood about 'potentially harmful vapors</p> <p>Scrutiny of PolyMet proposal turns to cleanupAcid Mine DrainageProposed copper-nickel mining involves exposure of sulfide minerals to air, waterMetalSO2 + H2O H2SO4Pollution could migrate to wetlands, parks, streams</p> <p>Mining plan includes treatment but timespan could be 200-500 years!water pollution solutionsBarriers can be constructed to isolate polluted sediments - plastic (impermeable) liners can also isolated toxic water in a systemAddition of nutrients - aluminum, calcium, iron reduces eutrophicationDredging removes sediments with toxic compounds - expensive but likely necessary</p> <p>Oxygen levels in a lake that is oxygen-depleted can be restored by aerationOften the most effective and economical way to treat polluted ground water is allow natural processes to remove or destroy pollutants; can be boosted by addition of beneficial organisms</p> <p>Decontamination after extraction is the last resort</p>