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