July 2014
Environmental Science Ch # 17.
SOLID WASTE MANAGEMENT and DISPOSAL
Introduction
Nature of Problems
Kinds of Solid Waste Solid – produced on site
Mining
Industrial
Agricultural
Municipal solid waste
Composition
Problems - Space
Causes
Waste Production
Historical Disposal method
Methods of Waste Disposal
Landfilling
Incineration
Composting
Source Reduction
Recycling – Examples
Concerns
What can you do to Reduce Waste and Save $$
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Introduction
Roots of solid waste disposal are in the post WW2 era. The “Throw away society” convenience.
Solid waste is 40% paper, 17% yard and 30% metal, glass and plastics.
Photo of the Day
Barge loaded with Solid waste (Fresh kill at Islip, NY), looking for a place to offload. 1987.
Reason: land cost, GW Contamination, Air Quality, Rodents and increase waste due to population
growth.
Nature of the Problem
17 – 1. Kinds of solid Waste
materials which people no longer want – 200 Million tons/ year. Discarded materials , approx 2
kg/day.
The nations with the highest std of living produce the most waste (paper, wood metal, glass, plastics)
Mining waste is left at the site of extraction – Tailings often contains hazardous material. Treated in
ponds.Contamination is restricted locally. 2000MMTons (max) /year produced
Strip mining > 75,000 sq km.
Agricultural waste is the 2nd. Most abundant. Derived from processing animals, seeds and
peelings,harvesting crops and trees. It is generally treated by incineration or used as a fertilizer.
Ground water pollution is associated with the latter method of disposal. (1240 M met Tons/year)
Industrial Waste - 200 to 600 MMTons/year. Aquatic, scraps, demolition waste and Sludge.
17 – 2. Municipal Waste –
In the US ¾ Ton/person/year produced. (4 lbs/person/day) more than 2X the waste in 1960.
Conclusions: Nations with high Standard of Living produce more solid waste per person than those
in the Undeveloped nations. It is anticipated that many cities in NA will run out of space by 2015 in
spite of waste reduction by 50%.
Historically, waste was disposed off by dumping outside the city limits, and later burnt.
Presently, landfill dumping is cheapest, next burning and then recycling. Waste reduction not
measured.
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17 – 3. Methods of Waste Disposal
Five techniques used.
1. Land fills. Not just a hole in the ground in which garbage is dumped. A modern landfill is
a depression with an impermeable clay layer. Furthermore, lined with an impermeable liner
membrane (plastic sheet). Each day’s deposit is covered over by earth.
The site has complex bottom layers for trapping leachate; monitoring system to detect methane gas;
ground water contamination testers; and cost is more than $1M / hectare to prepare.
Locating a new landfill requires:
Geological information.
Overcoming local opposition (NIMBY).
Japan sends 15% of waste to landfills, the US >57%.
2. Incineration. Prior to 1940 it was common practice in the US. It is now stopped due to
odor, ash, smoke and gases. Today there are 115 units operating, incinerating about 15% of the
waste. The heat is used to generate electricity.
Mass burn – high temp. operation 1300 degree C. Not used in the US due to waste composition. This
can reduce the volume of waste by up to 90% (weight by 75%).
Modern incinerators have precipitators, dual scrubbers and fabric filters (bag houses)
Its primary risk involves air quality issues, toxicity and ash. Small quantities of pollutants are
released into the atmosphere (metals, dioxins, furans- a class of chemicals, and acid gases).
The bottom ash may contain Hg, Pb, Cadminum, arsenic and other hazardous materials. Cost to
construct $45 to 350 M.
3. Producing Mulch and Compost
Composting. Harnessing the natural process of decomposition to transform organic matter into
compost. (green matter N2 is mixed with dry/ brown material) Carbon 1:3 ratio good after 8 – 10
weeks.
Large scale composting – material processed by shredding, turning and mixing.
Windrow – material formed into long rows and turned periodically.
Static aerated piles – material put into large piles and insulated with layers of manure.
Enclosed vessel – put material into a drum.
Benefits to using compost: Reduces bulk density, improves workability and soil porosity.
4. Source Reduction. The most fundamental way to reduce waste is to reuse. The benefits
are:
Reduces waste disposal and handling costs.
Conserves resources
Reduces pollution including greenhouse gases.
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Reduces toxicity in waste (cost).
Reduces reliance on other forms of waste disposal.
Economic savings to community.
Future : Pay as you throw, however that depends on how much is thrown away. Packaging is
reduced. Fewer raw material is purchase.
5. Recycling. Most successful in the US.
Container laws leads to 28% of solid waste kept out of landfills and incinerators.
A “Bottle Bill” enacted in Oregon 1972, bans the use of one time use beverage cans and bottles.
Purpose to reduce the amount of litter.
Maine expanded law to include all non dairy containers.
Examples: 1 Sunday Edit NY Times requires 62,000 trees – 40% recycled.
US imports 100% Al. Recycles 60%
Tin imported 100%. Possible to recover 2Kg from every 1000 cans
Glass cutlets use reduces energy requirements by 50% in addition to pollution.
Recycling concerns:
Technical – process varies from 1 product to another.
Economics – demand for recycled products
Currently the paper industry is committed to spend $1 B.
The Government tax structure does not support recycling programs.
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