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Solid Waste Management and Disposal

Chapter 18

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Kinds of Solid Waste

• Solid Waste is generally made of objects or particles that accumulate on the site where they are produced.

– Typically categorized by the sector of the economy responsible for producing them.

• Mining Wastes– Waste Material Left on Surface– Milling Tailings– Waste or Tailings Drainage

• Agricultural Waste– Includes waste from raising animals as well as crop and

tree harvesting. 90% is used as fertilizer or other forms of soil

enhancement.

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Kinds of Solid Waste• Industrial Solid Waste - Solid waste other than mining.

– Estimated 180-540 million tons annually. Demolition Waste Sludge Combustion Ash

• Municipal Solid Waste– All the materials people in a region no longer want.

230 million tons annually.• In modern society, many products are discarded when they are

broken or worn out, while others only have a temporary use.– Those that have only temporary uses make up the majority of solid

waste.• Unites States produces about 230 million tons of municipal solid

waste annually.– Equates to 2 kg of trash person / day.

Per capita waste has increased 70% since 1960.

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Municipal Solid Waste

• In modern society, many products are discarded when they are broken or worn out, while others only have a temporary use.

– Those that have only temporary uses make up the majority of solid waste.

• Unites States produces about 230 million tons of municipal solid waste annually.

– Equates to 2 kg of trash person / day. Per capita waste has increased 70% since 1960.

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Waste Generation and Lifestyle

•Nations with a higher standard of living tend to produce more municipal solid waste per person than less-developed countries.

–Large metropolitan areas have the greatest difficulty dealing with solid waste.

Traditional Methods (dumping and burning) no longer accepted.

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Methods of Waste Disposal

• Landfills– Municipal solid waste landfill typically a

depression in impermeable clay layer, lined with impermeable membrane.

Each day’s deposit of fresh garbage is covered with a layer of soil to prevent it from blowing around and to discourage animal scavengers.

Traditionally been primary method of waste disposal.

Cheap and Convenient

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Landfills

• New landfills have complex bottom layers to trap contaminant-laden leachate.– Monitoring systems are necessary to

detect methane gas production and groundwater contamination.

In some cases, methane collected and used to generate electricity.

• Currently cost up to $1 million per hectare to prepare.

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Modern Landfill

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Landfills

• Number of landfills is declining.– Many small landfills not meeting

regulations.– Capacity has been reached.

• New landfills often resisted due to public concerns over groundwater contamination, odors, and truck traffic.– Politicians are often unwilling to take

strong positions that might alienate constituents.

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Reducing the Number of Landfills

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Incineration• Currently, about 15% of U.S. municipal solid

waste is incinerated.– Production of electricity partially offsets

disposal costs.Most incinerators burn unprocessed

municipal solid waste. Mass Burn

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Incineration• Incinerators drastically reduce the amount of municipal waste.

– Up to 90% by volume and 75% by weight.• Primary risks of incineration involve air quality problems and

toxicity and disposal of ash.• Even with modern pollution controls, small amounts of

pollutants still released into environment• Cost of land and construction for new incinerators are also

major concerns facing many communities. Construction costs in North America in 2000 ranged

from $45 - $350 million.• U.S. EPA has not looked favorably on construction of new

waste-to-energy facilities.– Encouraged recycling and source reduction as more

effective solutions to deal with solid waste.

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Producing Mulch and Compost

• Mulch is organic material used to protect areas where the soil is disturbed, or to control growth of unwanted vegetation.

– Organic material chopped or shredded into smaller pieces.

• Composting is using natural decomposition to transform organic material into compost (humus-like product).

– With proper management of air and water, composting can transform large quantities over a short period of time.

• About 3,800 composting facilities currently in use in the United States.

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Diverting Waste Through Composting

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Source Reduction

• Simplest way to reduce waste is to prevent it from ever becoming waste in the first place.

– Source reduction is the practice of designing, manufacturing, purchasing, using and reusing materials so that the amount of waste or its toxicity is reduced.

• Design Changes– Since 2-liter soft drink bottle introduced in 1977, weight has been

reduced by 25%.• Manufacturing Processes

– Reduce waste, increase efficiency.• Purchasing Decisions

– Choose reduced packaging and plan quantities accordingly.• Reusing Items

– Delay or prevent entry of items into waste collection stream.

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Recycling

• In the United States, recycling (including composting) diverted about 30% of solid waste stream from landfills and incinerators in 2001.– Benefits

Resource ConservationPollution ReductionEnergy SavingsJob CreationLess Need for Landfills and Incinerators

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Recycling

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Recycling Programs

• Container Laws – Required deposit on all reusable beverage

containers.National bottle bill would reduce litter,

save energy and money, create jobs, and help conserve natural resources.

• Mandatory Recycling Laws– Provide statutory incentive to recycle.

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Recycling Programs

• Curbside Recycling– 1990 - 1,000 U.S. cities had curbside

recycling programs.Grown to 9,000 cities by 2000.

Cities with curbside recycling tend to have higher recycling rates than cities that lack such programs.

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Recycling Concerns

• Plastics are recyclable, but technology differs from plastic to plastic.– Milk Container

High-Density Polyethylene (HDPE)– Egg Container

Polystyrene (PS)– Soft-Drink Bottle

Poly-Ethylene Terephthalate (PET)http://lifecycle.plasticsresource.com/

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Increasing Amounts of Plastic in Trash

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