Chapter 16Waste Generation and Waste Disposal

Paper or Plastic?

• Polystyrene – plastic polymer with high insulation value• Aka – styrofoam

• Is harmful to environment• In response to public sentiment • Switch to paper cup… but is this really better?

• Use cradle-to-grave or life-cycle analysis:

Humans generate waste that other organisms cannot use…• Inputs – plant materials, nutrients, water, energy• Outputs – waste

• Anything not useful or consumed and nonuseful products

Municipal Solid Waste

• We live in a throw-away society• Planned obsolescence

• Municipal solid waste - refuse collected by municipalities from households, small businesses, and institutions such as schools, prisons, municipal buildings and hospitals• Varies

• Some stats:

Content of the Solid Waste Stream

• Waste stream – the flow of solid waste that is recycled, incinerated, placed in a solid waste landfill, or disposed of in another way

Composition of Municipal Solid Waste… another analysis

• 31% - paper• 33%- organic materials (yard waste, food scraps, wood)• 12%- plastic • 18%- durable goods (appliances, tires)

E-Waste

• Electronic waste (E-waste) - televisions, computers, cell phones that contain toxic metals• Great environmental effect • Little incentive to recycle

• Voluntary?• Concern

• US exports e-waste to China

Reduce, Reuse, Recycle

• Reduce- waste minimization or prevention• Source reduction

• Other benefits:• Packaging is concern

• Substitution

• Reuse• May involve repairing an existing object • Agents of reuse

• Recycle- next slide

The 3rd R

• Closed loop recycling vs. open-loop • In US - increased since 1975 • Zero-sort recycling programs

• Benefits…

• Requires more energy • Goal of Recycling?

Composting

• Organic material (ie. food and yard waste) cause problems in landfills• Compost

• Compostable material includes…• Meat/dairy usually not composted

• Composting tips:• Simple vs. sophisticated• C:N ratio of 30:1• Turn over compost regularly

Landfills

• Open dumps – still common in developing world• Sanitary landfills• Leachate

Sanitary Landfill

Sanitary Landfills

• Costs:• Building landfill is very expensive• Tipping fee

• Choosing a site for sanitary landfill:• Some requirements:• Siting is often controversial and can be politically charged

• Some problems with landfills:

Incineration

• Incineration• Ash – residual nonorganic material that does not combust during

incineration• Bottom ash • Fly ash

• Pollutants released included

How does incineration work?

Incineration

• Waste-to-energy – when heat generated by incineration is used rather than released in the atmosphere

Hazardous Waste

• Hazardous waste- liquid, solid, gaseous, or sludge waste material that is harmful to humans or ecosystems• Collection sites

• Periodic collection held• Once collected - sorted into a number of categories

• Hazardous waste must be treated

Laws

• Resource Conservation and Recovery Act (RCRA) - designed to protect human health and the natural environment by reducing or eliminating hazardous waste• Also know as “cradle-to-grave” tracking• RCRA ensures that hazardous waste is tracked and properly disposed of

• 1984 – Hazardous and Solid Waste Amendments (HSWA)

Laws

• Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)• Also know as “Superfund”• Puts a tax on the chemical and petroleum industries

• This revenue is used to cleanup …• Requires the federal government to respond directly to the release of

substance that may pose a threat to human health or the environment• Problems:

Superfund Sites in US

Brownfields

• Contaminated industrial or commercial sites that may require environmental cleanup before they can be redeveloped or expanded• Includes…

• Critics: inadequate solution to contaminated locations in country

International Consequences

• Municipalities and industries may send waste to countries with less stringent regulations• Examples:

• Tugboat Break of Dawn (from NY in 1987) • Khian Sea (a Bahamian ship hired by Philly in 1986)• Mercury from India to PA

Life Cycle Analysis

• Looks at the materials used and released throughout the lifetime of a product

Life Cycle Analysis

Alternative Ways to Handle WasteIntegrated Waste Management

• A method that seeks to develop as many options as possible, to reduce environmental harm and cost• Utilizes reduction, recycling, composting, landfills, and incineration• No single method works for everyone