gsc 1620 chapter 16 waste disposal. waste disposal most people think little about what happens to...

GSC 1620 Chapter 16

Waste Disposal

Waste Disposal

Most people think little about what happens to their refuse, but waste disposal has economic, environmental, health, even political ramifications

North America hosts about 8% of the world’s population, consumes one-third of the world’s resources and produces about half the world’s nonorganic garbage

In the U.S. the average person generates about 4.6 pounds of “garbage” daily

Waste Categories

In this chapter we’ll discuss solid and liquid waste disposal issues

The U.S. produces about 4 billion tons of solid waste annually but the primary sources of this waste surprises most people (see slide)

Primary solidwaste sourcesin the U.S., mid1980s

1990, US EPA

Solid Waste Disposal

Most people are also surprised to learn that paper is the primary source of municipal solid waste (see slide)

Typical municipalsolid waste sources, 2010


Although industrial solid waste constitutes only 8% of the total solid waste profile in the U.S., industrial solid waste releases the most environmental toxins (see slide)

Industrial solidwaste sources

*

• * projected tokeep increasingsubstantially; Why?

Important Future Issue

The book, Garbage Land: On the Secret Trail of Trash (published in 2005) notes that Americans now discard more than 100 million computers, cellular phones and other electronic devices (called e-waste) each year!

It’s estimated that 60 million computers have already been buried in landfills

Some efforts are being made to reduce e-waste (see slides) but e-waste recycling methods expose many to harmful substances especially in poor Asian countries or cities

E-waste

E-waste

Currently, most e-waste is recycled in Asia by poor people in unprotected conditions

Solid Waste Disposal Methods

Open Dumps – refuse dumped directly onto the ground; perhaps half of U.S. solid waste still disposed this way! (Relationship to “midnight dumping”?)

Associated problems: Exposed refuse is a fire hazard; foul-smelling

garbage attracts rodents and insects (increased disease transmission risk)

Exposed refuse a possible source of groundwater, surface water, soil and air contamination


Sanitary Landfill – in use since early twentieth century – a layer of compacted trash is covered each day by a layer of dirt (~ 3 - 6 in); this method reduces the odor and vermin

Often sited in old gravel pits or natural valleys; the ideal setting would have low permeability materials beneath the site and a deep water table (see slides)

Sanitary Landfill

Sanitary Landfills

Sanitary Landfills

Improper location increases the chance of ground and surface water and soil contamination from landfill leachate (infiltrated water and dissolved substances) (see slides)

Leachate

Potential leachate problems withimproper sanitarylandfill placement

Sanitary Landfills

Today most sanitary landfills are constructed with an impermeable base liner (usually plastic sheeting overlain with clay sediments) to prevent leachate escape

Unfortunately, virtually all sanitary landfills leak at some time, and even when they don’t the accumulating leachate can rise and escape the landfill margins (see slide)

Leachate“bathtub”effect

Sanitary Landfills

Extraction pipes can be used to pump the accumulated leachate from the landfill – but the extracted leachate creates another disposal problem

The average leachate composition (see table) may not seem threatening unless you understand that prolonged ingestion of seemingly low concentration toxins can be very harmful

Example of Some Dissolved Substances in Municipal Landfill Leachate

Substance Concentration Range (ppm)

copper 0 - 9

iron 0.2 – 5,500

lead* 0 - 5

manganese 0.06 – 1,400

nitrate 0 – 1,300

phosphate 0 - 154

zinc 0 – 1,000• *The Safe Water Drinking Act maximum contaminant level forlead is 15 ppb!

Landfills

Many sections of the U.S. face looming landfill capacity shortages (see slide), usually not due to lack of space for new landfill construction but public opposition to new site construction (e.g., NIMBY – Not in My Back Yard; NIMFYE – Not in My Front Yard Either)

1996 U.S.EPA assessment ofremaininglandfillcapacity

What controversy,partiallyinternational,surroundsMichigan’slandfill operators?

Typical landfilldisposal costs:New York: $140 perton; Ohio: $33 per ton!

2005

(What international treaty made this bandifficult to enact?)

In 2010, only 53% ofToronto’s solid wastewas trucked to MI landfills; rising fuel costs for transporting the refuse led to multiple new recycling and waste diversion programs


Incineration – combustion of solid waste Advantages: on average, reduces the volume of

solid waste by 80% Modern high-temperature (up to 3000O F)

incineration can decompose many harmful compounds into less hazardous substances

The combustion heat energy can be employed in a “waste-to-energy” facility to generate steam for space heating or electrical energy production (see slide)

Schematic diagram of a waste-to-energy facility

Incineration

Disadvantages: incineration solid residue may contain highly concentrated toxins

Requires separation of noncombustible waste, increasing costs

Typically releases a variety of pollutants to the air (e.g., chlorine gas, acidic vapors, toxic metals, carbon dioxide)

Even the high-temperature incinerators can’t destroy toxic elements (e.g., mercury, arsenic)

The high-temperature incinerators are very expensive to operate (~ $2000 per ton of waste), although the less effective low-temperature incinerators are more cost competitive (~ $75 per ton of waste)

Incineration

There is usually public opposition to new incinerator construction: a municipal incinerator proposed for Auburn Hills in the early 1990s was never constructed due to public opposition


Ocean dumping: methods – direct dumping or shipboard incineration followed by dumping of ash

Some view dumping waste into the ocean as a reasonable approach. Why?

Hundreds of millions of tons of solid waste and 6-10 million gallons of liquid waste dumped each year into the open ocean


The U.S. Ocean Dumping Ban Act of 1988 prohibited dumping of U.S. sewage sludge and industrial waste after 1991; unfortunately there is little compliance monitoring

While most industrial countries limit this practice, most Third World coastal countries are increasing ocean dumping


Some international treaties regulating ocean dumping have been negotiated but were never ratified by enough signatory countries to take effect

Dredge spoils (sediments dredged from reservoirs and streams) are still dumped into the oceans (including by the U.S.) at a rate of ~ 200 million tons/year

Dredge spoils can: cloud waters; introduce pollutants; alter water chemistry - Sediments can pollute waterways and negatively impact aquatic ecosystems


Ocean dumping is an example of the “dilute-and-disperse” philosophy of waste disposal

Reducing Solid Waste Volume

Composting – suitable for most organic material; finished compost is a soil additive, not a soil substitute

Many municipalities now require separation of leaves, grass clippings and other yard waste from the solid waste stream for municipal composting

Can you think of potential problems associated with small-scale (i.e., individual) and large-scale (i.e., municipal) composting?


Recycling – is most effective when the waste substance is pure or uncombined with other substances; e.g., aluminum cans are readily recycled because of their purity

Successes: state bottle deposit laws have reduced roadside litter and fostered recycling of certain materials

Potential problems: Requires source separation by individuals and businesses;

A market must exist for the recycled substance


We need to ensure that the appeal of recycling doesn’t conflict with overall waste and pollution reduction goals (Read “Decisions, Decisions” on page 377 of the text and consider how a “cradle to grave” analysis of material use is complicated and still may not produce satisfactory decision making knowledge concerning material use and disposal)


An Oakland Press article (11/28/04) stated that Michigan’s recycling rate (e.g., paper, cans and glass) lies between 15-20%; 46th in the nation (James Clift, Michigan Environmental Council)

According to the article, Minnesota spends $14.2 million, Wisconsin $29 million, and Indiana $3.2 million (annually) promoting and coordinating recycling efforts – Michigan spends about $200 thousand annually

Michigan’s estimated recycling rate in 2007: 20% (state report); about 10% lower than the Great Lakes states average


Packaging reduction – involves the elimination of unnecessary packaging, the design of packaging that requires less material and the design of manufacturing processes that necessitate less packaging for the products

Examples? College degrees (even Ph.D.s) are now offered

in packaging design and construction (locally: MSU)


Another option: “Waste Exchanges” Idea: “One man’s waste is another man’s

_______” The Internet has greatly facilitated the

market for waste exchanges Illustrate to me how this process was

utilized in the construction of the playing field bed at Detroit’s Ford Field.


A personal way to reduce solid waste – join a group like freecycle.org

What’s another personal choice that could reduce solid waste volume that involves liquid consumption?


Note in the following slides: The solid waste disposal practices

worldwide may differ substantially A lesser proportion of solid waste is being

landfilled in the U.S. compared to prior decades

The U.S. generates more solid waste than any other country

USA update: 1996 67 16 17

: 2007 54 13 33

Landfilled Incinerated Recycled

USA Recycling Data

Overall, only 8% of plastic products are recycled!

Comparative Solid Waste Generation

kilograms per capita per year

2009

Waste Consideration

It’s important to realize which waste is hazardous and what possible hazards may result from inadequate disposal

2001

Liquid Waste Disposal

Generally two categories: by-products of industrial processes and sewage

A huge problem of which most are unaware; example: over 1 billion gallons of petroleum-based used lubricants are produced in the U.S. each year – at least 400 million gallons are poured onto the ground or enters storm drains!

Huge volumes of liquid animal waste from Concentrated Animal Farming Operations (CAFOs) another concern we’ll review next chapter


Much liquid waste has been dumped into lakes, rivers and the oceans, following the dilute-and-disperse disposal philosophy

An opposite approach: concentrate-and-contain Examples: a secure landfill or deep-well

disposal; ideally multiple barriers are present to minimize the possibility of waste leakage and migration (see slides)

Secure Landfill

Bedrockdisposalof liquidwaste

(deep injectionwells)

Deep-Well Disposal

The federal government has utilized deep-well disposal for hazardous liquid waste for decades

Opponents have filed periodically successful lawsuits legally delaying the operation of MI’s first commercial deep disposal well (near Romulus) (see slides)

Deep-Well Disposal

Deep-well disposal of liquid waste is risky in active fault zones – Remember our earlier discussion?

Rocky Mountain Flats Arsenal, CO


Other strategies: Waste Exchanges Waste neutralization or decontamination

by chemical treatment (e.g., acid + base salt + water)

Incineration

Sewage Treatment

Obviously sewage contains disease-causing microorganisms – other problems will be discussed in the next chapter

In the U.S. about 20% of the population’s sewage is treated by “septic systems”, about 75-80% is treated by a municipal wastewater treatment facility

A properly operating septic system consists of a settling tank (accumulates solids) and a leaching field (filters certain contaminants from wastewater) (see slide)

Sewage Treatment

A properly operating septic system illustrates how some contaminants can be removed from polluted water; septic drain (leach) fields are composed of well-sorted (all particles about the same size) sands or gravels

The drain field works like a window screen; particles in the water bigger than the sediment pore spaces get trapped in the sediments (see slide); others may get absorbed to the material

Certain rocks and sediments (e.g., sands, permeable sandstones) may act similarly

What are somepotential problemswith this method?

Sewage Treatment

Municipal wastewater treatment can involve primary (mainly physical), secondary (mainly biological) and tertiary treatment (mainly chemical) (see figures)

Only about 2% of U.S. households served by tertiary treatment

More costly thanprimary andsecondarytreatment

~2% of U.S.population

Chicago produces~ 600 tons (dry)per day!

Detroit areaproblems:storm and sewerdrainsinterconnected.So?

Our Toxic Legacy

Thousands of environmental contamination sites exist in the U.S. because of improper waste disposal

A 1980 federal law known as “Superfund”, reauthorized several times since, sought to identify and remediate the worst sites of environmental contamination in the country

Although progress has been made (see slides) the problem is daunting: new sites are identified as, or more, quickly than the old ones can be cleaned!

The projected cost of Superfund sites cleanup exceeds $1 trillion!

Our Toxic Legacy (Superfund)

Superfund Sites, 2012 Remediated Sites RemovedFrom Superfund List

Radioactive Waste

What is the primary concern associated with solid or liquid radioactive waste?

Remember – there are different types of nuclear radiation with different penetration energies (see slide)

Penetration energies of different types of nuclear radiation

Radioactive Waste

Important consideration: the radioactive material’s half-life

Half-life – the time required for half of the radioactive atoms present to decompose; half-lives of radioactive elements vary from fractions of a second to billions of years! (see slide)

Radioactive Waste

The more energetic the nuclear radiation and the longer a radioactive substance’s half life the greater the disposal problem

E.G., Plutonium has a half-life of ~ 24,000 years and emits highly energetic nuclear radiation; plutonium waste would require at least 10 half-lives isolated storage for even modest amounts to have the radioactivity reduced to “safe” exposure levels

Radioactive Waste

Radioactive waste possesses another significant environmental and economic problem to the U.S. (see slide)

Radioactive Waste

Radioactive waste classification is imprecise; two broad categories recognized: Low-level radioactive waste: low-energy radioactivity emission; nearly 90% of all radioactive waste (e.g., certain medical waste, smoke alarms, protective clothing and filters from nuclear power plants) High-level radioactive waste: high-energy radioactivity emission (e.g., depleted U-fuel rods, most nuclear plant waste)

Although nearly 90%of radioactive wasteis “low-level”, the highest energyradiation is associated with “high-level” waste,especially depleted (spent) nuclear fuel

Radioactive Waste Disposal

No permanent repository exists anywhere in the world for high-level radioactive waste; very few sites have been constructed to accept low-level radioactive waste

The U.S. government created the Waste Isolation Pilot Plant (WIPP) to store transuranic waste (a type of nuclear waste with low-energy radioactivity emission but very long half-lives) produced during more than 50 years of nuclear weapons research and production


The waste will be deposited about 2,150 feet underground in tunnels and chambers dug into 225 million-year-old thick salt deposits

By law, no other low- or high-level radioactive waste can be deposited at the WIPP

The WIPP facility started receiving waste late in 2000 and should be able to store 6 million cubic feet of transuranic waste during its 35 year life expectancy (see slides)

Waste Isolation Pilot (WIPP) Plant Schematic Design

WIPP “multibarrier”containmentvessel

WIPP waste vessels are mechanically emplacedinto holes bored into salt walls


Suggestions for high-level radioactive disposal:

1) Space disposal 2) Ice sheet disposal (Antarctica) 3) Deep seabed disposal 4) Subduction zones 5) Bedrock caverns (e.g., like WIPP) or bedrock disposal

(Yucca Mountain, Nevada?) See slide illustrating multibarrier approach of bedrock

disposal (most likely to be employed in the U.S. for commercial high-level radioactive waste)

Example of bedrockdisposal for high-level radioactivenuclear waste


The Nuclear Waste Policy Act (NWPA) of 1982 mandated the establishment of two high-level radioactive waste disposal sites for commercial waste

In 1987 this Act was amended: only Yucca Mtn., Nevada was authorized to be investigated as a possible repository

The Yucca Mountain site has been beset by delays in the mandated Environmental Assessment and by legal challenges by state and local governments and individuals (see slide of Yucca Mtn. region seismicity)

Yucca Mountain, Nevada

Location of major faults Significant earthquakes


The NWPA of 1982 mandated the government open a permanent storage facility for high-level radioactive waste by 1998 – if the Yucca Mountain site is completed it will likely not open to 2015 or beyond! The 2010 budget eliminated all funding for Yucca Mountain!

The average nuclear power plant in the U.S. produces about 500 pounds of plutonium per year and 30 metric tons of high-level radioactive waste each year!

Where is this high-level radioactive waste stored now? (see slide for example)

12/27/05

The Russian government (2006)proposed storing, for payment, high-level radioactive waste like spentfuel rods. A good idea?


Technical and legal problems have also plagued construction of a new generation of low-level radioactive waste dumps – federal law is being violated

Discuss Michigan’s withdrawal from the Great Lakes compact on low-level radioactive waste disposal


We need to also worry about radioactive material contamination of the environment from other sources (e.g., a Russian nuclear-powered submarine with nuclear missiles sank in the northern Atlantic Ocean in 1986 with about 200 pounds of plutonium - an unknown amount leaked into the ocean)


The Hanford crisis is just one of numerous worrisome nuclear waste sites in the U.S.

Summary

Two broad waste disposal philosophies exist:1) Dilute-and-Disperse (i.e., “The solution to

pollution is dilution”.); example – ocean dumping

2) Concentrate-and-Contain (i.e., concentrate waste and isolate it from the environment); example – secure landfills, bedrock disposal of nuclear waste

Remember – neither of these approaches is risk free

gsc 1620 chapter 16 waste disposal. waste disposal most people think little about what happens to...

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