Waste Disposal
Chapter 15
Some Facts
In 1996, U.S. residents, businesses, and
institutions produced more than 209 million
tons of MSW, which is approximately 4.3 pounds
of waste per person per day, up from 2.7 pounds
per person per day in 1960 = mass of Statue of
Liberty every 5 years
United States
has 8% of world population
Consume 1/3rd of World’s resources
Produces ½ of World’s garbage
Handled on site
Not toxic
Not toxic
Areas of concern
1991 data
Paper: 50%
Municipal Waste
Open Dump
Sanitary Landfill
Incineration
Ocean dumping
Open Dump
Unsanitary, draws pests and vermin,
harmful runoff and leachates, toxic gases
Still accounts for half of solid waste
Several thousand open dumps in the USA
Sanitary Landfill
Sanitary Landfill
Layer of compacted trash covered with a layer of earth
once a day and a thicker layer when the site is full
Require impermeable barriers to stop escape of
leachates: can cause problem by overflow
Gases produced by decomposing garbage needs venting
1 acre/10,000 people: acute space problem: wastes piling
up over 150 million tons/year;
# of landfills down from 8000(1988) to 3091(1996)
NIMBY, NIMFYE, NIMEY, NOPE
NJ ships >5 million tons of waste every year
Incineration
Solves space problem but:
produces toxic gases like Cl, HCl, HCN, SO2
High temp furnaces break down hazardous compounds but
are expensive ($75 - $2K/ton)
Heat generated can be recovered: % of waste burnt
Japan 67%, Switzerland 80%, USA 6%
North Little Rock, AK saving $50K in heating cost and
reducing landfill requirement by 95%
How many MSW combustors exist in the United States?
In 1996, 110 combustors with energy recovery existed
with the capacity to burn up to 100,000 tons of MSW per
day.
Ocean Dumping
Out of sight, free of emission control norms
Contributes to ocean pollution
Can wash back on beaches, and can cause death of
marine mammals
Preferred method: incineration in open sea
Ocean Dumping Ban Act, 1988: bans dumping of
sewage sludge and industrial waste
Dredge spoils still dumped in oceans, can cause
habitat destruction and export of fluvial pollutants
Reducing Waste
Incineration, compacting
Hog feed: requires heat treatment
Composting: requires separation of organics from
glass and metals
Recycling and Reusing
Recycle of glass containers: 5 million tons
Plastic: marked by types for easy recycling
Converted into Fibers, trash bags, plastic lumber, fill for
pillows, insulation etc
Junked cars: 150 – 200 kg of plastics: soon to be recycled
•In 1996, recycling of solid waste
in the United States prevented the
release of 33 million tons of
carbon into the air—roughly the
amount emitted annually by 25
million cars.
•1 ton of newspaper=18 trees, 3
m3 of landfill, 60% less energy.
Govt recycling saving 223,000
tons, 4 million trees, $7.4 million
Auto Steel Aluminum Paper & Yard Glass Plastic Tires
Batteries Cans Packaging Paperboard waste container container
Waste Exchange
One persons waste can be another persons
raw material
Fluorite from Al smelter in MD
Isopropyl alcohol = cleaning solvent
Nitric Acid from Electronic Industry = high
grade fertilizer
Spent acid of steel industry = control for H2S
Liquid Waste
Sewage
Highly toxic Industrial Waste & Used Oil
Dilute and Disperse
Concentrate and Contain
Secure Landfill
Sealed drums to be put in impermeable holds with monitoring
wells to check for leakage: does not work
Deep well Disposal
Pumping in deep porous layer bounded by impermeable
formations, well below water table
$1 million to drill, $15-20/ton afterwards
Restricted by geological considerations, can trigger
earthquakes
Story of Love Canal
A ditch 20m wide, 3m deep and 1km long
1890: Built near Niagara falls for hydro-power
1905: Hooker Electrochemical established
1942: Hooker buys the site for waste disposal, 20,000 tons of toxic
chemical dumped in 10 yr
1953: site bought by Niagara School board for $1, Hooker absolved of any
future damage
1977: study shows toxic effects in adjoining homes,>40 toxic chemicals
identified
1978: Health advisory, 100 families to be shifted
1980: remedial measures taken, EPA study shows chromosome defects in
residents, President Carter declares emergency, provides federal aid
1981: Over 500 families moved out, hundreds waiting for aid
EPA estimate: 30,000 hazardous waste sites in US, only 10% of hazardous
wastes properly disposed, 300 million tons generated each year
Sewage Treatment
Individual scale
Settling tank (solids settle and are broken down)
Leaching field: receives liquids from septic tank
through porous pipes. Bacteria and oxygen breaks
down organics and disease causing germs
Should have soil layer = 60 cm below 150cm
above
Should not be within 15m of any water body
0.5 to 1 acre per dwelling
Municipal Sewage Treatment
75% of US population served by sewage system
and <5% releases untreated sewage
Primary treatment: removal of solids
Secondary treatment: biological
Bacteria and fungi breaks down organics
Chlorinated to kill germs, can form chloroform
which is carcinogenic
Tertiary treatment: Filtration and chemical
treatment: expensive
Sludge is a by-product and is rich in organics and
nutrients
Radioactive Waste Disposal
Isotopes with short half-lives are gone quickly, those
with long half-lives will decay too little
Low level wastes: 90% of all radioactive wastes
20 temporary and 6 commercial disposal sites
States to take care of their low level waste
High level wastes e.g., spent nuclear fuel rods
Should be so disposed as to cause less than 1000 death in
10,000 years
High Level Waste Depository
Rocketing to sun
Under Antarctica Ice sheet
Subduction Zone
Sea bed disposal
Bedrock caverns
Granites, basalt, tuff, shale, salt caverns
Salt: High melting point, impermeable in dry
condition, self-sealing, cheap resource
No permanent high level waste repository yet
Requirements for a radio-active
waste disposal system
Design and Fabricate a System that will
Last thousands of years longer than recorded
human history
Be robust enough to isolate highly radioactive
material so that it will not threaten human
health and environment for more than ten
thousand years.
Story of Yucca Mountain Site
1982: Nuclear Waste Policy Act
Congress charges DOE with the task
Two high level waste depository in the eastern and
the western USA
Billions collected from tax on utilities
1986: Hanford, Wa, Yucca Mtn, Ne and Deaf
Smith County, Tx shortlisted as western sites
1987: Congress suddenly decides on Nevada
(screw Nevada bill)
Nevada to receive $20 million/year
Feb 15, 2002: Pres. Bush approved Yucca Mtn as
the site for high level nuclear waste respository
Yucca Mountain Site
Geologically stable (?)
Limited fault displacement
No volcanism in 10,000 years
Tuff host rock, 1000 ft below the surface, 1000 ft
above the water table
Arid climate, no streams, low water table
Low population density
Federally owned land, close to Nevada test sites