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1. Lecture 14Lecture 14
WASTE MANAGEMENTWASTE MANAGEMENT
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2. Waste ManagementWaste Management
WastesWastes are any unwanted or discarded material from residential,are any unwanted or discarded material from residential,
commercial, industrial, or agricultural activities that may causecommercial, industrial, or agricultural activities that may cause
environmental problemsenvironmental problems
Waste managementWaste management is the collection, transport, processing oris the collection, transport, processing or
disposal, managing and monitoring ofdisposal, managing and monitoring of wastewaste materialsmaterials
Waste management is a problem in both urban and rural areas inWaste management is a problem in both urban and rural areas in
our country as elsewhere in the worldour country as elsewhere in the world
The goals of waste management:The goals of waste management:
To minimize waste quantityTo minimize waste quantity
To reduce the amount of raw materials consumedTo reduce the amount of raw materials consumed
To dispose of non-hazardous waste cost-effectivelyTo dispose of non-hazardous waste cost-effectively
To dispose of hazardous waste with minimal risk to human healthTo dispose of hazardous waste with minimal risk to human health
and the environmentand the environment

3. Waste ManagementWaste Management
 How Pollutants Enter the EnvironmentHow Pollutants Enter the Environment::
Hazardous-waste pollutants from a solid-waste disposal site mayHazardous-waste pollutants from a solid-waste disposal site may
enter the environment by as many as six paths:enter the environment by as many as six paths:
Methane, ammonia, hydrogen sulfide, and nitrogen gases may enterMethane, ammonia, hydrogen sulfide, and nitrogen gases may enter
the atmospherethe atmosphere
Heavy metals, such as lead, chromium, and iron may be retained inHeavy metals, such as lead, chromium, and iron may be retained in
the soilthe soil
Heavy metals and other toxic materials may enter food chain viaHeavy metals and other toxic materials may enter food chain via
plant uptake growing near the disposal siteplant uptake growing near the disposal site
Crop residue containing toxic substances returns these to the soilCrop residue containing toxic substances returns these to the soil
after decompositionafter decomposition
Soluble materials, such as chloride, nitrate, and sulfate may reachSoluble materials, such as chloride, nitrate, and sulfate may reach
the groundwater systemthe groundwater system
Overland runoff may transport leachate into streams and riversOverland runoff may transport leachate into streams and rivers

4. Waste ManagementWaste Management
Early conceptEarly concept of disposal wasof disposal was dilute and dispersedilute and disperse
With industrialization and urbanization early concept became inadequateWith industrialization and urbanization early concept became inadequate
AA new conceptnew concept known asknown as concentrate and containconcentrate and contain became popularbecame popular
However Containers may leak or break and allow waste to escapeHowever Containers may leak or break and allow waste to escape
Modern TrendsModern Trends
Consider waste as resource out of placeConsider waste as resource out of place
Cost of raw materials, energy, transportation and land make itCost of raw materials, energy, transportation and land make it
economically feasible toeconomically feasible to reuse & recyclereuse & recycle this kind of resourcesthis kind of resources
Under this concept waste would not exist because of recyclingUnder this concept waste would not exist because of recycling
If produced would be reused as a resourceIf produced would be reused as a resource
This concept is referred to as the “Zero waste” movementThis concept is referred to as the “Zero waste” movement

5. Waste ManagementWaste Management
Integrated Waste ManagementIntegrated Waste Management
A set of management alternativesA set of management alternatives
includesincludes thethe three R’sthree R’s of wasteof waste
prevention, incineration,prevention, incineration,
composting, and landfillcomposting, and landfill
TheThe ultimate objective of theultimate objective of the
three R’s of IWMthree R’s of IWM is to reduce theis to reduce the
amount of urban and other wasteamount of urban and other waste
By utilizingBy utilizing IWMIWM technologytechnology
weight of urban refuse could beweight of urban refuse could be
reduced to 50%, perhaps asreduced to 50%, perhaps as
much as 70% by early in the 21much as 70% by early in the 21stst
centurycentury
A 50% reduction by weight ofA 50% reduction by weight of
urban waste could be facilitatedurban waste could be facilitated
byby
1. Source r1. Source reductioneduction (10% reduction)(10% reduction)
2. R2. Recyclingecycling programs (30%programs (30%
reduction)reduction)
3. Large scale3. Large scale compostingcomposting programsprograms
(10% reduction)(10% reduction)
Two typesTwo types of recycling:of recycling:
(1)(1) closed-loopclosed-loop——
recycled to producerecycled to produce
new products of thenew products of the
same typesame type
(2)(2) Down cyclingDown cycling––
converted into differentconverted into different
lower quality productslower quality products
Through intensiveThrough intensive
recycling as much asrecycling as much as
80-90% of waste might80-90% of waste might
be recovered (USbe recovered (US
example)example)
More realistic is partialMore realistic is partial
recycling that canrecycling that can
provide 30% reductionprovide 30% reduction
Steel crushed & baled for
recycling

6. Waste ManagementWaste Management
CompostingComposting
A component of IWMA component of IWM
A biochemical process by aerobicA biochemical process by aerobic
organisms of rapid, partialorganisms of rapid, partial
decomposition of moist, solid, organicdecomposition of moist, solid, organic
waste such as lawn clippings andwaste such as lawn clippings and
kitchen scraps to a rich, soil-likekitchen scraps to a rich, soil-like
materialmaterial
Reduces volume, can be used asReduces volume, can be used as
organic fertilizerorganic fertilizer
Nevertheless, compost can be used asNevertheless, compost can be used as
an organic soil fertilizer, topsoil, oran organic soil fertilizer, topsoil, or
landfill coverlandfill cover
An active compost heap

7. Waste ManagementWaste Management
IncinerationIncineration
Combustible waste is burned at 900-1000Combustible waste is burned at 900-1000
00
C to consume all combustible material,C to consume all combustible material,
leaving only ash and noncombustibles toleaving only ash and noncombustibles to
dispose of in a landfilldispose of in a landfill
May reduce the volume of waste by 75%May reduce the volume of waste by 75%
to 95% (actually to 50%)to 95% (actually to 50%)
Incineration can be used to supplementIncineration can be used to supplement
other fuels and generate electric powerother fuels and generate electric power
 DrawbacksDrawbacks
Not a clean processNot a clean process
May produce pollution and toxic ashMay produce pollution and toxic ash
May emit oxides of nitrogen, sulfurMay emit oxides of nitrogen, sulfur
Heavy metals– lead, cadmium, mercuryHeavy metals– lead, cadmium, mercury
Carbon monoxideCarbon monoxide

8. Waste ManagementWaste Management
Open DumpsOpen Dumps
(Landfill)(Landfill)
Open dumps createOpen dumps create
a nuisance by beinga nuisance by being
unsightly, providingunsightly, providing
breeding groundsbreeding grounds
for pests, creating afor pests, creating a
health hazard,health hazard,
polluting the air,polluting the air,
pollutingpolluting
groundwater andgroundwater and
surface watersurface water

9. Waste ManagementWaste Management
Sanitary LandfillsSanitary Landfills
Most common and economic method in manyMost common and economic method in many
countriescountries
Concentrate and contain refuse (contrast to openConcentrate and contain refuse (contrast to open
dumping) without creating a nuisance or hazarddumping) without creating a nuisance or hazard
to public health or safetyto public health or safety
It is covered with a layer of compacted soil at theIt is covered with a layer of compacted soil at the
end of each day of operationend of each day of operation
Covering the waste is what makes the landfillCovering the waste is what makes the landfill
sanitarysanitary
The compacted layer minimizes the amount ofThe compacted layer minimizes the amount of
surface water entering into and gas escapingsurface water entering into and gas escaping
from the waste and restricts continued access tofrom the waste and restricts continued access to
the waste by insects, rodents, and other animals,the waste by insects, rodents, and other animals,
such as seagullssuch as seagulls
Modern sanitary landfills are engineered toModern sanitary landfills are engineered to
include multiple barriers, such as clay and plasticinclude multiple barriers, such as clay and plastic
liners to limit movement of leachateliners to limit movement of leachate

10. Environmental Impacts of LandfillsEnvironmental Impacts of Landfills
 A major concern with regard toA major concern with regard to
landfills is the potential water pollutionlandfills is the potential water pollution
from the rainwater that percolatesfrom the rainwater that percolates
through the wastes, dissolving andthrough the wastes, dissolving and
carrying away all organic andcarrying away all organic and
inorganic contaminantsinorganic contaminants
 Many of the contaminants in landfillMany of the contaminants in landfill
leachate are highly toxic and wouldleachate are highly toxic and would
create a serious pollution problem ifcreate a serious pollution problem if
they reach the groundwaterthey reach the groundwater
 The production of methane gas by theThe production of methane gas by the
anaerobic decomposition of organicanaerobic decomposition of organic
wastes in a landfill can present a verywastes in a landfill can present a very
serious explosion hazard if the gas isserious explosion hazard if the gas is
not collectednot collected
 Possibly burned as an energy sourcePossibly burned as an energy source
Electricity generator powered by landfill waste

11. Products we Use Potentially Hazardous Waste
Leather Heavy metals, organic solvents
Medicines Organic solvents and residues, heavy metals (e.g., Hg, Zn)
Metals Heavy metals, fluorides, cyanides, acid and alkaline
cleaners, solvents, pigments
Oil, gasoline & other
petroleum products
Oil, phenols and other organic compounds, heavy metals,
ammonia, salts, acids
Paints Heavy metals, pigments, solvents, organic residues
Pesticides Organic chlorine compounds, organic phosphate
compounds
Plastics Organic chlorine compounds
Textiles Heavy metals, dyes, organic chlorine compounds, solvents
Table W: Products and the Potentially Hazardous Waste they Generate (Q)
Of 70,000 chemicals approximately 35,000 are definitely or potentially hazardous to public health
Uncontrolled dumping of chemical waste pollutes soil, surface water and groundwater
Hazardous Chemical Waste Management

12. Hazardous waste
Industrial waste

13. Waste ManagementWaste Management
Hazardous chemical waste management is one of the most serious environmentalHazardous chemical waste management is one of the most serious environmental
problemsproblems
Management involves recycling, on-site processing to recover by-products, microbialManagement involves recycling, on-site processing to recover by-products, microbial
breakdown, chemical stabilization, high temperature decomposition, incineration, disposalbreakdown, chemical stabilization, high temperature decomposition, incineration, disposal
by secure landfillby secure landfill
A number of technological advances have been made in toxic-waste management, and asA number of technological advances have been made in toxic-waste management, and as
land disposal becomes more expensive, the recent trend toward on site treatment is likelyland disposal becomes more expensive, the recent trend toward on site treatment is likely
to continueto continue
On-site treatment will not eliminate all hazardous chemical wasteOn-site treatment will not eliminate all hazardous chemical waste
Disposal of some waste will remain necessaryDisposal of some waste will remain necessary
All available technologies cause some environmental disruptionAll available technologies cause some environmental disruption
There is no simple solution for all waste management issuesThere is no simple solution for all waste management issues
Even with extensive safeguards land disposal cannot guarantee that the waste isEven with extensive safeguards land disposal cannot guarantee that the waste is
contained and will not cause environmental disruption in the futurecontained and will not cause environmental disruption in the future
Pollution of groundwater is perhaps the most significant risk, because groundwater providesPollution of groundwater is perhaps the most significant risk, because groundwater provides
a convenient route for pollutants to reach humans and other living thingsa convenient route for pollutants to reach humans and other living things

14. End of SlidesEnd of Slides
Thank YouThank You