APES Ch 22 waste management

sanitary landfills

In modern sanitary landfills, waste is buried in the ground or piled up in large mounds engineered to prevent waste from contaminating the environment and threatening public health.

top MSW in the US : before recycling

In the United States, paper, food scraps, yard trimmings, and plastics are the principal components of municipal solid waste, together accounting for two-thirds of what enters the waste stream.

industrial solid waste

Industrial solid waste includes waste from production of consumer goods, mining, agriculture, and petroleum extraction and refining.

brownfields

Later laws also charged the EPA with cleaning up brownfields, lands whose reuse or development is complicated by the presence of hazardous materials.

industrial ecology

-A holistic approach that integrates principles from engineering, chemistry, ecology, and economics, industrial ecology seeks to redesign industrial systems to reduce resource inputs and to maximize both physical and economic efficiency. -everything produced in a manufacturing process is used, either within that process or in a different one.

waste

-As the world's population rises, and as we produce and consume more material goods, we generate more waste. -Waste refers to any unwanted material or substance that results from a human activity or process. Waste can degrade water quality, soil quality, air quality, and human health. -Waste also indicates inefficiency—so reducing waste can save money and

hazardous waste

Hazardous waste refers to solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive.

regulation and industrial solid waste

-Businesses that dispose of their own waste on site must design and manage their landfills in ways that meet state, local, or tribal guidelines. -Other businesses pay to have their waste disposed of at municipal disposal sites. -Whereas the federal government regulates municipal solid waste, state or local governments regulate industrial solid waste (with federal guidance). -Regulation varies greatly from place to place, but in most cases, state and local regulation of industrial solid waste is less strict than federal regulation of municipal solid waste.

landfill gas

-Combustion in WTE plants is not the only way to gain energy from waste. -Deep inside landfills, bacteria decompose waste in an oxygen-deficient environment. -This anaerobic decomposition produces landfill gas, a mix of gases roughly half of which is methane. -Landfill gas can be collected, processed, and used in the same way as natural gas. -Today hundreds of landfills are collecting landfill gas and selling it for energy.

composting process

-Composting is the conversion of organic waste into mulch or humus through natural decomposition. -We can place waste in compost piles, underground pits, or specially constructed containers. -As waste is added, heat from microbial action builds in the interior and decomposition proceeds. -Banana peels, coffee grounds, grass clippings, autumn leaves, and other organic items can be converted into rich, high-quality compost through the actions of earthworms, bacteria, soil mites, sow bugs, and other detritivores and decomposers. -The compost is then used to enrich soil.

composting

-Composting is the practice of recovering organic waste (such as food and yard waste) by converting it to mulch or humus through natural biological processes of decomposition. -Recycling and composting are fundamental features of the way natural systems function; all materials in nature are broken down at some point, and matter cycles through ecosystems.

downsides to sanitary landfills

-Despite improvements in liner technology and landfill siting, however, liners can be punctured, and leachate collection systems eventually cease to be maintained. -Moreover, landfills are kept dry to reduce leachate, but the bacteria that break down material thrive in wet conditions. -Dryness, therefore, slows waste decomposition. -In fact, the low-oxygen conditions of most landfills turn trash into a sort of time capsule. -Researchers examining landfills often find some of their contents perfectly preserved, even after years or decades.

reuse strategies

-Habits as simple as bringing your own coffee cup to coffee shops or bringing sturdy reusable cloth bags to the grocery store can, over time, have substantial impact. -You can also donate unwanted items and shop for used items yourself at yard sales and resale centers. -Used items are often every bit as functional as new ones, and they are usually much cheaper.

hazardous waste reduction

-High costs of disposal, however, have also encouraged conscientious businesses to invest in reducing their hazardous waste. -Many biologically hazardous materials can be broken down by incineration at high temperatures in cement kilns. -Others can be treated by exposure to bacteria that break down harmful components and synthesize them into new compounds. -In addition, various plants have been bred or engineered to take up specific contaminants from soil and break down organic contaminants into safer compounds or concentrate heavy metals in their tissues. -The plants are eventually harvested and disposed of.

inefficiency in industrial solid waste

-However, physical efficiency is not always reflected in economic efficiency. -Often it is cheaper for industry to manufacture its products or perform its services quickly but messily. -In such cases, economic efficiency is maximized, but physical efficiency is not. -Because our market system awards only economic efficiency, all too often industry has no financial incentive to achieve physical efficiency. -The frequent mismatch between these two types of efficiency is a major reason why the output of industrial waste is so great. -Rising costs of waste disposal enhance the financial incentive to decrease waste.

types of hazardous waste

-Ignitable. Likely to catch fire (for example, gasoline or alcohol). -Corrosive. Apt to corrode metals in storage tanks or equipment (for example, strong acids or bases). -Reactive. Chemically unstable and readily able to react with other compounds, often explosively or by producing noxious fumes (for example, ammonia reacting with chlorine bleach). T-oxic. Harmful to human health when inhaled, ingested, or touched (for example, pesticides or heavy metals).

CERCLA

-In 1980, however, the U.S. Congress passed the Comprehensive Environmental Response Compensation and Liability Act (CERCLA). -This law established a federal program to clean up U.S. sites polluted with hazardous waste. -The EPA administers this cleanup program, called the Superfund. -Under EPA auspices, experts identify sites polluted with hazardous chemicals, take action to protect groundwater, and clean up the pollution.

sanitary landfill steps/characteristics

-In a sanitary landfill, waste is partially decomposed by bacteria and compresses under its own weight to take up less space. -Soil is layered along with the waste to speed decomposition, reduce odor, and lessen infestation by pests. -Some infiltration of rainwater into the landfill is good, because it encourages biodegradation by bacteria—yet too much is not good, because contaminants can escape if water carries them out. -The bottoms and sides of sanitary landfills must be lined with heavy-duty plastic and 60-120 cm (2-4 ft) of impermeable clay to help prevent contaminants from seeping into aquifers. -Sanitary landfills also have systems of pipes, collection ponds, and treatment facilities to collect and treat leachate

deep-well injection

-In deep-well injection, a well is drilled deep beneath the water table into porous rock, and wastes are injected into it. -The process aims to keep waste deep underground, isolated from groundwater and human contact. -However, wells can corrode and can leak wastes into soil, contaminating aquifers, and deep-well injection may very occasionally induce earthquakes.

the economics of recycling

-In fact, many of our popular municipal recycling programs are run at an economic loss. -The expense required to collect, sort, and process recycled goods is often more than recyclables are worth in the marketplace. -In addition, the more people recycle, the more glass, paper, and plastic is available to manufacturers for purchase, which drives down prices. -And transporting items to recycling facilities can sometimes involve surprisingly long distances. -The low commodity prices of recent years have also posed a challenge to recycling programs. -Recycling advocates, however, point out that market prices do not take into account external costs—in particular, the environmental and health impacts of not recycling.

incineration benefits

-Incinerating waste reduces its weight by up to 85% and its volume by up to 95%. -WTE production with combustion and steam/heat!

waste to energy facilities

-Incineration was initially practiced simply to reduce the volume of waste, but today it often serves to generate electricity as well. -Most incinerators now are waste-to-energy (WTE) facilities, which use the heat produced by waste combustion to boil water, creating steam that drives electricity generation or that fuels heating systems. -When burned, waste generates about 35% of the energy generated by burning coal. -Revenues from power generation, however, are often not enough to offset the considerable financial cost of building and running incinerators. -Because it can take many years for a WTE facility to become profitable, companies that build and operate these facilities sometimes require communities contracting with them to guarantee the facility a minimum amount of garbage.

life-cycle analysis

-Industrial ecologists pursue their goals in several ways: -They examine the entire life-cycle of a given product—from its origins in raw materials, through its manufacturing, to its use, and finally its disposal—and look for ways to make the process more efficient. -This strategy is called life-cycle analysis.

hazardous waste sources

-Industry, mining, households, small businesses, agriculture, utilities, and building demolition all create hazardous waste. -Industry produces the most, but in developed nations industrial waste disposal is often highly regulated. -As a result, households are now the largest source of unregulated hazardous waste. -Household hazardous waste includes a wide range of items, including paints, batteries, oils, solvents, cleaning agents, lubricants, and pesticides.

materials recovery facilities

-Items collected are taken to materials recovery facilities (MRFs), where workers and machines sort items using automated processes including magnetic pulleys, optical sensors, water currents, and air classifiers that separate items by weight and size. -The facilities clean the materials, shred them, and prepare them for reprocessing.

incineration

-Just as sanitary landfills are an improvement over open dumping, incineration in specially constructed facilities is better than open-air burning of trash. -Incineration, or combustion, is a controlled process in which garbage is burned at very high temperatures. -At incineration facilities, waste is generally sorted and metals are removed. -Metal-free waste is chopped into small pieces to aid combustion and then is burned in a furnace.

surface impoundments

-Liquid hazardous waste, or waste in dissolved form, may be stored in surface impoundments, shallow depressions lined with plastic and an impervious material, such as clay. -The liquid or slurry is placed in the pond and water is allowed to evaporate, leaving a residue of solid hazardous waste on the bottom. -This process is repeated and eventually the dry residue is removed and transported elsewhere for permanent disposal. -Impoundments are not ideal. -The underlying layer can crack and leak waste. -Some material may evaporate or blow into surrounding areas. -Rainstorms may cause waste to overflow and contaminate nearby areas.

three main components of waste management

-Minimizing the amount of waste we generate -Recovering discarded materials and finding ways to recycle them -Disposing of waste safely and effectively

source reduction

-Minimizing waste at its source—called source reduction—is the preferred approach. -We can achieve source reduction when manufacturers use materials more efficiently, or when consumers buy fewer goods, buy goods with less packaging, or use those goods longer. -Reusing goods you already own, purchasing used items, and donating your used items for others all help reduce the amount of material entering the waste stream.

electronic waste disposal

-Most electronic items we discard have ended up in conventional sanitary landfills and incinerators. -However, electronic products contain heavy metals and toxic flame-retardants, and research suggests that e-waste should instead be treated as hazardous waste. -The EPA and a number of states are now taking steps to keep e-waste out of conventional landfills and incinerators and instead treat it as hazardous waste. -Fortunately, the downsizing of many electronic items and the shift toward mobile devices and tablets mean that fewer raw materials by weight are now going into electronics being manufactured—and, as a result, U.S. e-waste generation appears to have recently peaked.

Resource Conservation and Recovery Act

-Most municipal landfills in the United States are regulated locally or by the states, but they must meet national standards set by the U.S. Environmental Protection Agency (EPA) under the Resource Conservation and Recovery Act , a major federal law enacted in 1976 and amended in 1984.

sanitary landfill recovery

-Once a landfill is closed, it is capped with an engineered cover consisting of layers of plastic, gravel, and soil. -Managers are required to maintain leachate collection systems for 30 years after a landfill has closed, and regulations require that groundwater be monitored regularly for contamination.

source reduction tactics

-One means of source reduction is to lessen the materials used to package goods. -Packaging helps to preserve freshness, prevent breakage, protect against tampering, and provide information—yet much packaging is extraneous. -Consumers can give manufacturers incentive to reduce packaging by choosing minimally packaged goods, buying unwrapped fruit and vegetables, and buying food from the bulk sections of stores. -Manufacturers can also reduce the size or weight of goods and materials -These lightweight polyethylene bags can persist for centuries in the environment, choking and entangling wildlife and littering the landscape—yet Americans discard 100 billion of them each year. -Financial incentives are also effective.

top MSW in the US: after recycling

-Paper is recycled at a high rate and yard trimmings are composted at a high rate, so after recycling and composting reduce the waste stream, food scraps and plastics are left as the largest components of U.S. municipal solid waste. -In developing nations, food scraps are often the primary component, and paper makes up a smaller proportion.

organic compounds and heavy metals

-Plastic containers, rubber tires, pesticides, solvents, and wood preservatives are useful to us precisely because they resist decomposition. -We use these substances to protect buildings from decay, kill pests that attack crops, and keep stored goods intact. -However, the capacity of these compounds to resist decay is a double-edged sword, for it also makes them persistent pollutants. -Many synthetic organic compounds are toxic because they are readily absorbed through the skin and can act as mutagens, carcinogens, teratogens, and endocrine disruptors. -Heavy metals such as lead, chromium, mercury, arsenic, cadmium, tin, and copper are used widely in industry for wiring, electronics, metal plating, metal fabrication, pigments, and dyes.

cradle-to-cradle approach

-Regardless of how well we reduce our waste stream through source reduction and recovery, there will likely always be some waste left to dispose of. -The linear movement of products from their manufacture to their disposal is often described as "cradle-to-grave." -As much as possible, however, the modern waste manager attempts to follow a cradle-to-cradle approach instead—one in which the materials from products are recovered and reused to create new products.

toxic fly ash

-The ash remaining after trash is incinerated contains toxic components and therefore must be disposed of in hazardous waste landfills. -Moreover, when trash is burned, hazardous chemicals—including dioxins, heavy metals, and polychlorinated biphenyls (PCBs) —can be created and released into the atmosphere. -Particulate matter, called fly ash, often contains some of the worst dioxin and heavy metal pollutants in incinerator emissions. -To physically remove these tiny particles, facilities may use a huge system of filters known as a baghouse.

three steps: recycling

-The first step is to collect and process used goods and materials, as is being done on so many campuses. -Once readied, these materials are used to manufacture new goods—the second step in the recycling loop. -If the recycling loop is to function, consumers and businesses must complete the third step in the cycle by purchasing ecolabeled products made from recycled materials.

recovery

-The next-best strategy in waste management is recovery, which consists of recovering, or removing, waste from the waste stream. -Recovery includes recycling and composting.

"the throwaway society"

-The relative wastefulness of the U.S. lifestyle, with its excess packaging and reliance on nondurable goods, has caused critics to label the United States "the throwaway society." -However, thanks to source reduction and reuse (especially by busi- nesses looking to cut costs), Americans now generate slightly less waste per capita than they did in the period between 1990 and 2005. -In developing nations, people consume fewer resources and goods and, as a result, generate less waste. -However, consumption is intensifying in developing nations as they become more affluent, and consequently these nations are generating increasing amounts of waste.

bottle bills

-To encourage recycling, composting, and source reduction, waste managers frequently offer consumers economic incentives to reduce the waste stream. -Bottle bills are another approach hinging on financial incentives. In the 10 U.S. states and 23 nations that have these laws, consumers pay a deposit on bottles or cans upon purchase—often 5 cents per container—and then receive a refund when they return them to stores after use. -inflation is a problem, however

electronic waste

-Today's proliferation of computers, printers, smartphones, tablets, TVs, DVD players, MP3 players, and other electronic technology has created a substantial new source of waste. -These products have short life spans before people judge them obsolete, and most are discarded after just a few years. -The amount of this electronic waste—often called e-waste—has grown rapidly, and now makes up more than 1% of the U.S. solid waste stream by weight.

Resource Conservation and Recovery Act: hazardous waste

-Under the Resource Conservation and Recovery Act, the EPA sets standards by which states manage hazardous waste. -The act also requires large generators of hazardous waste to obtain permits. Finally, it mandates that hazardous materials be tracked "from cradle to grave." -As hazardous waste is generated, transported, and disposed of, the producer, carrier, and disposal facility must each report to the EPA the type and amount of material generated; its location, origin, and destination; and the way it is handled. -This process is intended to prevent illegal dumping and to encourage the use of reputable waste carriers and disposal facilities.

municipal solid waste

Municipal solid waste is nonliquid waste that comes from homes, institutions, and small businesses.

recycling

Recycling is the process of collecting used goods and sending them to facilities that extract and reprocess raw materials that can then be used to manufacture new goods.

leachate

Sanitary landfills also have systems of pipes, collection ponds, and treatment facilities to collect and treat leachate, liquid that results when substances from the trash dissolve in water as rainwater percolates downward.

where do landfills need to be away from?

To protect against environmental contamination, U.S. regulations require that landfills be located away from wetlands and earthquake-prone faults and be at least 6 m (20 ft) above the water table.

waste stream

the flow of waste as it moves from its sources toward disposal destinations.