Waste Disposal Chapter 15. Solid Wastes Major source of solid waste in U.S. are: Major source of...
-
Upload
clifton-nicholson -
Category
Documents
-
view
219 -
download
0
Transcript of Waste Disposal Chapter 15. Solid Wastes Major source of solid waste in U.S. are: Major source of...
Waste DisposalWaste Disposal
Chapter 15Chapter 15
Solid WastesSolid Wastes
Major source of solid waste in U.S. are:Major source of solid waste in U.S. are:
– Agriculture (crops and animals): more than Agriculture (crops and animals): more than 50%50%
– Mineral industry (spoils, tailings, slag, and Mineral industry (spoils, tailings, slag, and other rock and mineral wastes)other rock and mineral wastes)
– Municipalities (small amount of municipal Municipalities (small amount of municipal waste)waste)
– Industry (highly toxic)Industry (highly toxic)
Figure 15.1Figure 15.1
Figure 15.2Figure 15.2
Municipal Waste DisposalMunicipal Waste Disposal
Open Dumps – unsightly, unsanitary, and Open Dumps – unsightly, unsanitary, and smellysmelly
Sanitary LandfillsSanitary Landfills – alternate layers of – alternate layers of compacted trash and a covering materialcompacted trash and a covering material– In U.S. open dumps no longer toleratedIn U.S. open dumps no longer tolerated– Landfill design is importantLandfill design is important– Barriers need to lock in toxins and chemicals; must Barriers need to lock in toxins and chemicals; must
reduce leakage into the environmentreduce leakage into the environment– Important to control the migration of Important to control the migration of leachateleachate out out
of the landfillof the landfill Sites for sanitary landfills often controversialSites for sanitary landfills often controversial
– NIMBY, NIMFY, NIMEY, and NOPE laws applyNIMBY, NIMFY, NIMEY, and NOPE laws apply
Figure 15.3Figure 15.3
Fig. 15.4 Sanitary Fig. 15.4 Sanitary landfillslandfills
Fig. 15.5 landfill and Fig. 15.5 landfill and LeachateLeachate
Fig. 15.6 “bathtub Fig. 15.6 “bathtub effect”effect”
Figure 15.7 Remaining landfill capacityFigure 15.7 Remaining landfill capacity
IncinerationIncineration Partial solution to space problems faced by Partial solution to space problems faced by
landfillslandfills Burning waste produces abundant carbon Burning waste produces abundant carbon
dioxide plus other toxic substancesdioxide plus other toxic substances Recent technology have improved incinerators Recent technology have improved incinerators
to burn hotter that breakdown complex toxic to burn hotter that breakdown complex toxic substances to less dangerous onessubstances to less dangerous ones
Expensive to operate and still produce a Expensive to operate and still produce a residual waste; often toxic and require proper residual waste; often toxic and require proper storagestorage
The considerable heat generated by an The considerable heat generated by an incinerator can be recovered and usedincinerator can be recovered and used
Figure 15.8 Proportions of municipal wasteFigure 15.8 Proportions of municipal waste
Figure 15.9 Waste-to-energy incineration facilityFigure 15.9 Waste-to-energy incineration facility
Ocean DumpingOcean Dumping Ship board incineration, over the open Ship board incineration, over the open
ocean, and dumping residual waste into ocean, and dumping residual waste into the oceanthe ocean– Similar to land-based incineration but at seaSimilar to land-based incineration but at sea– Incineration not 100% effective, residual toxic Incineration not 100% effective, residual toxic
materials and chemicals dumped into the ocean materials and chemicals dumped into the ocean will still pollute the oceanwill still pollute the ocean
Ocean dumping without incineration still Ocean dumping without incineration still popular in many places around the worldpopular in many places around the world– Very disastrous to local oceans where practicedVery disastrous to local oceans where practiced
A dumping site for one very high-volume A dumping site for one very high-volume waste product: dredge spoilswaste product: dredge spoils
Figure 15.10 Dumping sediments with pollutantsFigure 15.10 Dumping sediments with pollutants
Reduce Waste VolumeReduce Waste Volume Less volume means less landfill space and Less volume means less landfill space and
slower filling of available sitesslower filling of available sites Handling (Nontoxic) Organic MatterHandling (Nontoxic) Organic Matter
– Treated nontoxic organic waste can be fed to Treated nontoxic organic waste can be fed to swine or compostedswine or composted
Recycling – any reuse of waste reduces Recycling – any reuse of waste reduces volume at landfillsvolume at landfills– Recover recyclable waste by Recover recyclable waste by source separationsource separation; ;
separate waste into useful categories (wood, separate waste into useful categories (wood, paper, plastics, various metals, …) at the user’s paper, plastics, various metals, …) at the user’s sitesite
– Deposits on reusable material (glass, cans, Deposits on reusable material (glass, cans, containers, …) often attractive incentivecontainers, …) often attractive incentive
– Many applications to this idea yet unexploredMany applications to this idea yet unexplored
Figures 15.12 Solid wastes and paper recycleFigures 15.12 Solid wastes and paper recycle
Figure 15.13 Recycling Figure 15.13 Recycling
SymbolsSymbols
Figures 15.14 RecyclingFigures 15.14 Recycling
Reduce Waste VolumeReduce Waste Volume
Another optionsAnother options• Recycle crushed pavement as new Recycle crushed pavement as new
roadbed materialroadbed material• Recycle steel into other useful objectsRecycle steel into other useful objects• Re-use bricks as footpathsRe-use bricks as footpaths• Innovation has no limit hereInnovation has no limit here
Figure 15.15 Municipal waste disposalFigure 15.15 Municipal waste disposal
Figure 15.16 Main generators of hazardous wastesFigure 15.16 Main generators of hazardous wastes
Liquid-Waste DisposalLiquid-Waste Disposal Sewage and by-products of industrial Sewage and by-products of industrial
processesprocesses Strategies:Strategies:
– Dilute and disperseDilute and disperse– Concentrate and containConcentrate and contain
Neither strategy is safe in long termNeither strategy is safe in long term Secure LandfillsSecure Landfills – is it possible?– is it possible?
– Placing liquid-waste into sealed drums, and Placing liquid-waste into sealed drums, and covering with impermeable lining material; idea is covering with impermeable lining material; idea is to assure that the leachate will not migrateto assure that the leachate will not migrate
Deep wells – inject deep into the crustDeep wells – inject deep into the crust– Leachate not containedLeachate not contained– May act to lubricate faultsMay act to lubricate faults– Expensive and unsafeExpensive and unsafe
Fig. 15.17 Careless toxic-waste disposal leads to Fig. 15.17 Careless toxic-waste disposal leads to pollutionpollution
Figure 15.18 A secure landfill design for toxic-waste Figure 15.18 A secure landfill design for toxic-waste
disposaldisposal
Fig. 15.19 Deep-well Fig. 15.19 Deep-well disposal for liquid disposal for liquid wasteswastes
Other StrategiesOther Strategies
Incineration – produces carbon Incineration – produces carbon dioxidedioxide
Treatment by chemicals to Treatment by chemicals to breakdown or neutralized liquid breakdown or neutralized liquid waste is a possibilitywaste is a possibility– Generate a less toxic liquid or residueGenerate a less toxic liquid or residue– Would still require proper storageWould still require proper storage
Sewage TreatmentSewage Treatment Septic Systems: individual user-level Septic Systems: individual user-level
treatmenttreatment– Settling tank: solids separated and Settling tank: solids separated and
bacterial breakdown beginsbacterial breakdown begins– Leach field or absorption field: liquid with Leach field or absorption field: liquid with
remaining dissolved organic matter seeps remaining dissolved organic matter seeps out of porous pipesout of porous pipes
– Soil microorganisms and oxygen complete Soil microorganisms and oxygen complete the breakdown of the organic matterthe breakdown of the organic matter
– Soil permeability and field size are Soil permeability and field size are controlling factorscontrolling factors
Figure 15.20 Septic tank systemFigure 15.20 Septic tank system
Sewage TreatmentSewage Treatment Municipal Sewage TreatmentMunicipal Sewage Treatment
– Primary treatment: removal of solids Primary treatment: removal of solids from organic liquid wastefrom organic liquid waste
– Secondary treatment: bacteria and fungi Secondary treatment: bacteria and fungi act to dissolve and breakdown the act to dissolve and breakdown the organic matterorganic matter
– Tertiary or advanced treatment: Tertiary or advanced treatment: filtration, chlorination, and other filtration, chlorination, and other chemical treatment may occurchemical treatment may occur
Figure 15.21 Primary, secondary, and Figure 15.21 Primary, secondary, and tertiary stages of municipal treatmenttertiary stages of municipal treatment
Ghosts of Toxins Past:Ghosts of Toxins Past:SuperfundSuperfund
Disposal of identifiable toxic wastes Disposal of identifiable toxic wastes in U.S. is currently controlledin U.S. is currently controlled
Congress has mandated and Congress has mandated and provided billions of dollars to control provided billions of dollars to control and clean-up toxic spills from the and clean-up toxic spills from the pastpast– ExpensiveExpensive– Political dynamitePolitical dynamite
Figure 15.22 The first Figure 15.22 The first 951 toxic-waste dump 951 toxic-waste dump sitessites
Figure 15.23 Figure 15.23 Completed removals Completed removals of Superfund, 1980-of Superfund, 1980-19901990
Radioactive WastesRadioactive Wastes
Radioactive Decay – unstable nuclei decay Radioactive Decay – unstable nuclei decay and produce energyand produce energy
Radioisotopes each have their own rate of Radioisotopes each have their own rate of decay measured in a decay measured in a half-lifehalf-life
Half-lives of different radioisotopes vary Half-lives of different radioisotopes vary from microseconds to billions of yearsfrom microseconds to billions of years
The decay of a radioisotope can not be The decay of a radioisotope can not be accelerated or delayedaccelerated or delayed
Energetic radioisotopes must be contained Energetic radioisotopes must be contained out of the environment for ‘ever’out of the environment for ‘ever’
Figure 15.27Figure 15.27
Figure 15.25Figure 15.25
Table 15.2Table 15.2
Figure 15.26Figure 15.26
Effects of RadiationEffects of Radiation
Alpha, beta, and gamma rays are types of Alpha, beta, and gamma rays are types of ionized radiation given off by the decay of ionized radiation given off by the decay of various radioisotopesvarious radioisotopes
Cancer, tumors, tissue burns, and genetic Cancer, tumors, tissue burns, and genetic mutation can result due to exposure of mutation can result due to exposure of high doses of radiationhigh doses of radiation
Large doses result in deathLarge doses result in death Accidents have occurred:Accidents have occurred:
– Chernobyl and Three Mile IslandChernobyl and Three Mile Island
Nature of Radioactive Nature of Radioactive WastesWastes
Radioisotopes with half-lives of a few years Radioisotopes with half-lives of a few years to hundreds of years present the most riskto hundreds of years present the most risk– Radioactive enough to cause harmRadioactive enough to cause harm– Persistent in the environment long enough to Persistent in the environment long enough to
require managementrequire management– Some are toxic chemical poisonsSome are toxic chemical poisons
Levels of radioactive waste:Levels of radioactive waste:– Low-level: do not require extraordinary Low-level: do not require extraordinary
disposal precautionsdisposal precautions– High-level: require extraordinary precautions; High-level: require extraordinary precautions;
must be isolated from the biosphere with must be isolated from the biosphere with confidence for a long timeconfidence for a long time
Historical Suggestions for Historical Suggestions for StorageStorage
SpaceSpace Antarctic IceAntarctic Ice Plate Tectonic Subduction ZonesPlate Tectonic Subduction Zones Seabed DisposalSeabed Disposal Bedrock Caverns for Liquid WasteBedrock Caverns for Liquid Waste Bedrock Disposal of Solid High-Level Bedrock Disposal of Solid High-Level
WastesWastes– Multiple barrier conceptMultiple barrier concept
Figure 15.28Figure 15.28
Waste Isolation Pilot Plant Waste Isolation Pilot Plant (WIPP)(WIPP)
Southeast New Mexico site for storage Southeast New Mexico site for storage of of transuranic wastestransuranic wastes– Opened March 26, 1999Opened March 26, 1999
WIPP is located in bedded salt WIPP is located in bedded salt underlain by evaporites and overlain underlain by evaporites and overlain by mudstoneby mudstone– Located 2150 feet below the surface in a Located 2150 feet below the surface in a
dry and stable tectonic regiondry and stable tectonic region– Tectonic stable for over 200 million yearsTectonic stable for over 200 million years
Figure 15.29 aFigure 15.29 a
Figure 15.29 bFigure 15.29 b
Figure 15.30Figure 15.30
Yucca MountainYucca Mountain Established by Nuclear Waste Policy Established by Nuclear Waste Policy
Act of 1982 – establish a high-level Act of 1982 – establish a high-level disposal site in the westdisposal site in the west
Yucca Mountain Attractive Yucca Mountain Attractive Characteristics:Characteristics:– Tuff host rockTuff host rock– Arid climateArid climate– Low population densityLow population density– Low regional water tableLow regional water table– Apparent geologic stabilityApparent geologic stability
Geological studies were detailed and Geological studies were detailed and revealingrevealing
Figure 15.31 aFigure 15.31 a
Figure 15.31 bFigure 15.31 b
Figure 15.32Figure 15.32