ch. 19 material diff

Solid Waste Management Solid Waste Management and Disposaland Disposal

OutlineOutline

BackgroundWaste Disposal Methods– Landfills– Incineration

Source ReductionRecycling– Pros and Cons

IntroductionIntroduction

Lack of dumping space has become a problem for many large metropolitan areas

Communities are increasingly concerned about waste disposal costs, and groundwater and air quality hazards.

Disposable DecadesDisposable Decades

In the mid 1950’s a disposable lifestyle was marketed as the wave of the future, and as a way to reduce household duties.

Consumerism began in earnest following WWII.

Convenience was sold to prosperous post-war consumers. “Convenience” was quickly changed to necessity.

Nature of the ProblemNature of the Problem

Garbage = Municipal Solid Waste US produces 220 million metric tons of

municipal waste per year. US volume has more than doubled since 1960. MDCs have a higher standard of living, and

thus produce more waste. Traditional Methods (dumping and burning)

are no longer accepted.

Waste Disposal MethodsWaste Disposal Methods

Landfills Landfilling has traditionally been the primary

method of waste disposal - cheap and convenient.

Modern landfills have complex impermeable bottom layers to trap contaminants, and daily deposits are covered by layer of dirt.– Methane gas and leachate detection

systems.

Currently, almost 80% of NA municipal solid waste is deposited in landfills.

New landfills are often resisted due to public concerns over groundwater contamination, odors, and truck traffic.

Due to tight, anaerobic conditions, biological decay in modern landfills is retarded.

What is the largest man made structure on the planet?

Opened as a "temporary landfill" in 1947, The Fresh Kills Landfill covers 2200 acres, can be seen with the naked eye from space and is taller then the Statue of Liberty, at a height of 225 ft. It is situated on the western shore of Staten Island and is made up of four sections which contain fifty plus years of landfill, mostly in the form of household waste. The waste disposed at the Fresh Kills Landfill and the decomposition products of this waste contain numerous chemicals. The chemicals can enter into the environment in a variety of ways: releases into the air from barge unloading and garbage trucks unloading; the cement crushing trucks releases chemical dust into the air; and into the local groundwater by leaching.

IncinerationIncineration

Prior to 1940, incineration was common in NA and western Europe.

Many incinerators were eliminated because of aesthetic concerns.

Currently, about 16% of US municipal solid waste is incinerated.–Derived heat often used for electrical

generation.

Incinerators drastically reduce the amount of municipal solid waste - up to 90% by volume and 75% by weight.

Even with modern pollution controls, small amounts of pollutants are still released into env.

Cost and siting of new incinerators major problems facing communities.

Source ReductionSource Reduction

Most fundamental method of reducing waste is to prevent it from being produced.– Since 2 liter soft drink bottle was

introduced in 1977, weight has been reduced by 35%

– Since 1965, aluminum cans have been reduced in weight by 35%.

RecyclingRecycling

Currently 23% of NA waste is recycled.Recycling initiatives have grown rapidly

in NA during the past several years.

Recycling BenefitsRecycling Benefits

Resource ConservationPollution ReductionExample: Crushed glass reduces the

energy required to manufacture new glass by 50%

Example: One Sunday edition of N.Y. times consumes 62,000 trees. Only 20% of NA paper is recycled.

Recycling ConcernsRecycling Concerns

Plastics are recyclable, but technology differs from plastic to plastic.– Industry is researching new

technologies.Economics are of concern. Unless

demand for products keeps pace with growing supply, recycling programs will face an uncertain future.

Long-term success of recycling programs is also tied to other economic incentives such as taxation and the development of and demand for products manufactured from recycled materials.

Currently in the US, it is often still cheaper to use virgin material than transport recycled materials.

SummarySummary

Post WWII, increased consumption of consumer goods became a way of life.

Municipal solid waste is managed by:– Landfilling Incineration– Waste Reduction Recycling

Waste prevention is the most fundamental waste reduction technique

Recycling can only be successful if markets exist for recycled materials.

Maybe the best method of “disposal” is not to produce it in the first place ...