Chapter 22 Topics:  Types of waste  Managing waste  Conventional waste disposal  Management tools  Industrial solid waste management  Managing hazardous waste

Types of waste  Waste = any unwanted material or substance that results from human activity or process  Municipal solid waste = non-liquid waste from homes, institutions, and small businesses  Industrial solid waste = from production of goods, mining, agriculture, petroleum extraction and refining  Hazardous waste = solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive  Wastewater = from household, business, or industry; or polluted runoff from streets and storm drains

Waste management  The objective of waste management:  Minimize the amount of waste generated (source reduction)  Reuse or re-purpose  Recover waste materials and recycle/compost them  Dispose of waste safely and effectively  Source reduction is the preferred approach

The flow of waste  Waste stream = the flow of waste as it moves from its sources toward disposal destinations  Source reduction = use materials efficiently, consume less, buy goods with less packaging, use goods longer  Recovery (recycling, composting) = next best strategy in waste management  Recycling = sends used goods to facilities to manufacture into new goods (e.g., newspaper)  Composting = recovery of organic waste  But there will always be some waste left to dispose of

Municipal solid waste  Municipal solid waste also called “trash” or “garbage”  In the U.S., paper, yard debris, food scraps, and plastics are the principal components of municipal solid waste  Even after recycling, most solid waste is paper  Most municipal solid waste comes from packaging and nondurable goods (discarded after a short time of use)  As we get more goods, we generate more waste – U.S. citizens generate 1 ton/person each year

Disposal methods have improved  People used to dump their garbage wherever it suited them  Now, most industrialized nations bury waste in lined and covered landfills or burn it in incineration facilities  Recycling is reducing the pressure on US landfills

Sanitary landfills  Sanitary landfills = waste buried in the ground or piled in large, engineered mounds designed and constructed to prevent contamination and health threats  U.S. landfills are regulated under the Resource Conservation and Recovery Act (RCRA) of 1976  Waste is partly decomposed by bacteria and compresses under its own weight to make more space  Soil layers reduce odor and infestation by pests  Closed landfills must be capped and maintained

Landfill leachate  Leachate = formed within a landfill as waste liquids and infiltration react chemically with the solid waste  Leachate management  Reduce leachate production by minimizing infiltration – this is done with landfill “covers” (soils and membranes)  Preventing the migration of leachate out of the bottom of the landfill – this is done with a “liner”  Collecting and treating the leachate that accumulates at the bottom of the landfill – this is done with a “collection system”

Landfill design features

Landfill gas recovery  Landfill gas = produced when bacteria decompose waste in a landfill’s oxygen-deficient  A mix of gases that consists of 50% methane  Can be collected, processed, and used like natural gas  When not used commercially, landfill gas is burned off to reduce odors and greenhouse emissions

Incineration  Incineration = a controlled process that burns garbage at very high temperatures  Incineration reduces the volume of waste  Incineration in specially constructed faculties can be an improvement over open-air burning of trash  The remaining ash must be disposed of in a hazardous waste landfill  Hazardous chemicals can be created and released

A typical solid waste incinerator

Waste-to-energy  Waste-to-energy (WTE) facilities = use the heat produced by waste combustion to create electricity  Over 100 facilities are in use across the U.S.  They process nearly 100,000 tons of waste per day  But they take many years to become profitable  Companies contract with communities to guarantee a minimum amount of garbage  Long-term commitments interfere with the communities’ efforts to reduce and recycle waste

Management tools – reduction  Source reduction = preventing waste in the first place  Avoids costs of recycling and disposal  Helps conserve resources  Minimizes pollution  Can save consumers and businesses money  Most waste consists of materials used to package goods – source reduction to address this issue would include  Using minimal packaging  Using recyclable packaging  Reducing the size or weight of goods and materials

Management tools – reuse  Reusing items keeps them out of the waste stream  Use durable goods used instead of disposable ones  Donate items to resale centers (e.g., Goodwill)  Rent or borrow items instead of buying them  Bring your own cup to coffee shops  Buy rechargeable batteries  Make double-sided copies

Management tools – composting  Composting = the conversion of organic waste into mulch or humus through natural decomposition  Home composting:  Householders place waste into composting piles, underground pits, or specially constructed containers  Heat from microbial action builds up and decomposition proceeds  Earthworms, bacteria, and other organisms convert waste into high-quality compost

Large-scale composting  Municipal composting reduces landfill waste by diverting food and yard waste from the waste stream to central composting facilities  Half of U.S. states now ban yard wastes from the municipal waste stream, accelerating the move to composting  The resulting mulch can be used for gardens and landscaping  Enriches soil and encourages soil biodiversity  Makes healthier plants and more pleasing gardens  Reduces the need for chemical fertilizers

Management tools – recycling  Recycling = collecting materials that can be broken down and reprocessed to manufacture new items  Recycling diverted 61 million tons of materials away from incinerators and landfills in 2008  Greenhouse gas emissions equal to 10 billion gallons of gas are prevented each year

Recycling must go full circle  There are three parts to recycling  collection and processing of recyclable materials through curbside recycling or designated locations  using recyclables to produce new goods  consumers purchasing goods made from recycled materials  All three parts are necessary

Recycling rates vary widely

Perspectives on recycling  Growth in recycling results from  Municipalities’ desire to reduce waste  The public’s satisfaction in recycling  Recycling is not always profitable  It is expensive to collect, sort, and process materials  The more material recycled, the lower the price  Market forces do not take fully into account  The health and environmental effects of not recycling  The enormous energy and material savings

Industrial waste  Waste from factories, mining, agriculture, petroleum extraction, etc.  U.S. industries generate 7.6 billion tons/year  97% is wastewater  State/local governments regulate industrial solid waste (with federal guidance)

Economics plays a bigger role  Most methods for industrial waste reduction, recycling, and disposal are similar to municipal solid waste  State/local regulations may not required permits, installation of liners or leachate collection systems, or monitoring groundwater for contamination  Industries are awarded for economic, not physical, efficiency  So they don’t have incentives to decrease waste  It may be cheaper to generate waste than to avoid it

“Industrial ecology”  Industrial systems could function like ecological systems, with little waste  Industrial ecology = redesigning industrial systems to reduce resource inputs while maximizing physical and economic efficiency  Life cycle analysis = examines the life cycle of a product to make the process more ecologically efficient  Waste products can be used as raw materials  Eliminates harmful products and materials  Creates durable, recyclable, or reusable products

An example of industrial ecology

Hazardous waste  Hazardous waste is a liquid, solid, or gas and is one of the following:  Toxic = harms human health when inhaled, ingested, or contact human skin  Reactive = chemically unstable and readily reacts with other compounds, often explosively or by producing noxious fumes  Ignitable = easily catches fire (natural gas, alcohol)  Corrosive = corrodes metals in storage tanks or equipment

Sources of hazardous waste  Industry produces most of our hazardous waste  Mining, manufacturing, agriculture, utilities, building demolition, and businesses all produce hazardous wastes  Industrial waste generation is highly regulated

Sources of hazardous waste  Households are the largest source of unregulated hazardous wastes, including paint, batteries, solvents, cleaners, and pesticides.  Since the 1980s, cities have designated sites or collection days to gather household hazardous waste

“E waste” – new to the scene  Electronic waste (“e- waste”) = waste from electronic devices such as computers, printers, cell phones, TVs, etc.  Americans discard 400 million devices/year – 67% are still in working  They should be treated as hazardous waste but are not

Chemistry of hazardous waste  Organic compounds and heavy metals are hazardous because their toxicity persists over time  Hazardous site investigations analyze for  Volatile organic compounds (VOCs) – solvents and fuels  Semi-volatile organic compounds (SVOCs) – plasticizers, tars, polycyclic aromatic hydrocarbons  Pesticides and PCBs (polychlorinated biphenyls)  Heavy metals (e.g., lead, chromium, arsenic, cadmium)

Hazardous waste disposal  Hazardous waste used to be discarded without special treatment  The degree of harm was not understood  “Dilution is the solution to pollution”  Hazardous waste generation and disposal in now regulated by the Resource Conservation and Recovery Act (RCRA) (1976, 1984)

“Cradle to grave”  Under RCRA, hazardous waste gets a “paper trail”  Generators of hazardous waste must obtain permits describing how the waste is generated, and how it is managed or stored on site before being shipped to a treatment or disposal facility  Transporters of hazardous waste must be licensed  Treatment and disposal facilities must obtain permits describing how the waste will be managed, and the measures taken to ensure waste constituents do not migrate into the environment

Disposal methods - landfills  Design and construction standards are stricter than for ordinary sanitary landfills  Must have several impervious liners and leachate removal systems  The hazardous character of the waste is not changed, but the waste is isolated from people, wildlife, and ecosystems

Disposal methods – impoundments  Surface impoundments, shallow depressions lined with plastic and clay, store liquid hazardous waste  The water evaporates and the residue is transported elsewhere for treatment or disposal

Disposal methods – injection  Deep-well injection = liquid waste is injected into a well drilled deep in the Earth, isolating it from the environment  The disposal layer has highly saline ground- water that is not suitable for drinking  Micro-earthquakes have been linked to this method

Radioactive waste  Radioactive waste is very dangerous and persistent  The U.S. has no designated single disposal site and waste is accumulating at individual power plants  The Waste Isolation Pilot Plant (WIPP) = the first underground repository for transuranic waste from nuclear weapons development  Caverns are 2,150 ft below ground in a huge salt formation thought to be geologically stable  WIPP became operational in 1999 and is receiving thousands of shipments of waste

CERCLA – Cleaning up the past  Many former military and industrial sites are contaminated with hazardous waste  Illegal dumping also created large numbers of sites contaminated with hazardous waste  Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (1980) “Superfund” established a federal program to clean up U.S. sites polluted with hazardous waste

The origins of Superfund  Two events spurred creation of Superfund  Love Canal, New York, families were evacuated after buried chemicals rose to the surface  Times Beach, Missouri, the town was evacuated after oil sprayed on roads was found to contain dioxin

The Superfund process  Once a potential Superfund site is identified, EPA scientists perform a Preliminary Assessment/Site Inspection (PA/SI) to determine:  How close the site is to human habitation  If wastes are currently confined or likely to spread  If the site threatens drinking water supplies  If an imminent hazard is posed, an expedited Immediate Removal action can be taken.

The Superfund process  Sites with the potential to pose long-term, continuing hazards are placed on the National Priority List (NPL)  Sites are investigated in detail (Remedial Investigation – RI)  Ranked by their level of risk to human health and the environment (Risk Assessment)  The feasibility of different cleanup options is evaluated and a remedial action is proposed (Feasibility Study – FS )

The Superfund process  Public hearings are held to inform area residents of the RI/RA/FS findings and to receive feedback on the proposed remedial action  The Remedial Action is performed as funds are available  Long-term monitoring of the Remedial Action is performed

Who pays?  Superfund was designed to operate under the principle that “the polluter pays”  If the responsible parties could be identified, they paid  If not, a trust fund (based on a federal tax on petroleum and chemical industries) was used  Congress allowed the tax authorization to expire and the trust fund is bankrupt  Taxpayers pay all investigation and cleanup costs  Fewer cleanups are being completed (341 have been cleaned up but 1,279 sites remain listed)