Chapter 16Waste Generation and

Waste Disposal

Refuse collected by municipalities from households, small businesses, and institutions such as schools, prisons, municipal buildings and hospitals.

Municipal Solid Waste

31% - paper 33%- organic materials (yard waste, food

scraps, wood) 12%- plastic 18%- durable goods (appliances, tires)

Composition of Municipal Solid Waste

1.5% of total waste stream 33% of MSW is recycled or composted,

55% landfilled, 15% burned in incinerator 3M company reduced solid waste by

70%, saved 750 million

Electronic waste (E-waste) televisions, computers, cell phones that contain toxic metals.

E-Waste

Reduce- waste minimization or prevention

Reuse- reusing something like a disposable cup more than once

Recycle- materials are collected and converted into raw materials and then used to produce new objects

Reduce, Reuse, Recycle

Reduce use Redsign manufacturing process Trash taxes (Denmark) Pay as you throw (trash bags)

Denmark, Finland, and Prince Edward Island have banned beverage containers that can’t be reused

San Francisco has banned the use of plastic shopping bags. Residents are encouraged to use cloth.

Plastic vs paper grocery bags Less energy, less landfill space vs renewable

resource, less danger if swallowed (cloth is best)

Disposable vs cloth diapers Manufacuring, landfill vs cleaning effects

Tires (250 million discarded each year) 2.5 to 4 billion used tires are in US

MSW: 50% recycled in Switzerland and Japan, 33% in US

Primary (closed loop) vs secondary recycling (playground mulch from tires)

Paper can be downgraded (writing paper to newsprint to toilet paper)

High quality is available

2000, US recycled 49% of wastepaper

Chlorine used to bleach, hydrogen peroxide and ozone are replacing chlorine

Recycled from preconsumer vs post consumer waste

Germany: take back packaging

Netherlands: no pckg in landfill

Sell service instead of goods (Xerox)

Large scale (480 in US)

Separate, recycle or burn (electricity) Source separation (home or business) has

advantages Single stream recycling is done at Archmere Ash to landfill

Aluminum is valuable

4 % of US plastic is recycled

Difficult to recycle b/c many different, incompatible layers of polymers are used (PET [polyethylene terephthalate] in 2 liter bottles has one polymer, 20% is recycled)

Coca-Cola announced goal to recycle 100% of PET bottles

Compost- organic material that has decomposed under controlled conditions to produce an organic-rich material.

Composting

Turn periodically to raise temp, kill pathogens and weed seeds

Siting plants is difficult (NIMBY)

Fig. 21-10, p. 570

Uses worms to aerate organic material

Sanitary landfills- engineered ground facilities designed to hold MSW with as little contamination of the surrounding environment as possible.

Leachate- the water that leaches through the solid waste and removes various chemical compounds with which it comes into contact.

Landfills

When landfill is full, layers of soil and clay seal in trash

Topsoil

Sand Electricity generator buildingClay

Garbage Methane storage and compressor building

Leachate treatment system

Probes to detect methane leaks

Pipes collect explosive methane for use as fuel to generate electricity

Methane gas recovery well

Leachate storage tankCompacted

solid waste

Leachate pipesGarbage Leachate pumped

up to storage tank for safe disposal

Groundwater monitoring wellSand

Synthetic liner

Leachate monitoring wellSand Groundwater

ClayClay and plastic lining to prevent leaks; pipes collect leachate from bottom of landfill

Subsoil

54% of waste in US is landfilled Sand, clay layers around synthetic liner Leachate is pumped from bottom, sent to

water treatment plant Except for Phila, NYC no shortage of

space Methane (anaerobic decomp) can be

collected (Tullytown, PA)

Incineration- the process of burning waste materials to reduce its volume and mass and sometimes to generate electricity and heat.

Incineration

Temperatures up to 3,600oF 16% of MSW is burned 170 incinerators in US

Fig. 21-13, p. 575

Electricity

Turbine SmokestackCrane

Steam

Generator

FurnaceWet

scrubberBoiler

Electrostatic precipitator

Waste pit

Water added

Conveyor

Bottom ash

Dirty water Fly ash

Ash for treatment, disposal in landfill, or use as landfill cover

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

Collection sites for hazardous waste must be staffed with specially trained personnel.

Hazardous waste must be treated before disposal.

Hazardous Waste

Resource Conservation and Recovery Act (RCRA)- designed to reduce or eliminate hazardous waste. Also know as “cradle-to-grave” tracking.

RCRA ensures that hazardous waste is tracked and properly disposed of.

Laws

Resource Conservation and Recovery Act, 1976, amended in 1984

Requires EPA to identify hazardous waste and set standards for management by states

Firms with more than 220 lbs need permit stating how waste is managed

Permit holders use “cradle to grave” system

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 abandoned and nonoperating hazardous waste sites where a responsible party cannot be found.

Requires the federal government to respond directly to the release of substance that may pose a threat to human health or the environment

Superfund

Comprehensive Environmental Response, Compensation, and Liability Act, 1980

National Priorities List Polluter pays principle Joint and several liability 321 sites cleaned up, average $20 million

per site

Fig. 21-26, p. 583

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

Old factories, industrial areas and waterfronts, dry cleaners, gas stations, landfills, and rail yards are some examples.

Brownfields

Abandoned industrial and commercial sites, usually contaminated (factories, gas stations, etc)

450,000-600,000 in US, 40k redeveloped Clean up efforts are hampered by fear of

liability Congress and many states have passed

laws limiting liability of lenders and developers

A method that seeks to develop as many options as possible, to reduce environmental harm and cost.

Reduction, recycling, composting, landfills, and incineration are some ways IWM is utilized.

Integrated Waste Management

US National Academy of Sciences offers three priorities for dealing with haz mat Produce less of it Convert it to less hazardous substances Put rest in long-term, safe storage

1/3 of hazardous waste produced in Europe is sold as raw materials to other industries In US, only 10% is recycled

Basel Convention on Hazardous Waste 1995 amended version, bans export of

hazardous waste from developed to developing countries

Created due to Khian Sea waste disposal incident (Philadelphia incinerator ash)

US has signed but not ratified

Fig. 21-18, p. 579