waste disposal

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