Exam 5

Municipal solid waste (MSW)

consists of materials that are discarded from homes, small businesses, and institutions (e.g., hospitals and universities)

Industrial solid waste (ISW)

Waste produced in industrial processes before a finished product reaches the consumer

Current types of waste disposal

• waste-to-energy incineration

• sanitary landfills

• composting

• dumping (illegal)

No. 1 waste disposal option in the US

sanitary landfills

Characteristics of modern landfills

• trenches to deposit waste
• compacting to compress waste into smaller chunks
• daily burial to keep waste underground and combat rodent and odor problems
• pipes to vent gases
• plastic lining and impervious clay to protect groundwater

Modern Landfills are designed to:

• prevent accumulation of methane gas
• prevent contamination of groundwater
• prevent creation of odors
• reduce and control of pests (disease vectors)

Leachate

polluted liquid produced by water passing through buried wastes in a landfill

Environmental risks of landfills

• Groundwater contamination (failing liners)
• Greenhouse gas leaking
• Long-distance transport
• Loss of useful materials (paper, metals, plastics)
• Landfills must be monitored for decades after closure to ensure no pollution concerns
• Landfills are filling up and construction of new landfills is not keeping up with the amount of waste produced

Marine Protection, Research and Sanctuaries Act (MPRSA)

- often called the Ocean Dumping Act (1972)
• Regulates the dumping of all materials which would adversely affect human health

Compost

• decayed organic matter that can be used to improve the fertility and water-holding capacity of soil (improves plant growth)
• Rich in nutrients

Composting

aerobic (with oxygen) decomposition of organic waste by bacteria

hazardous waste

waste that is flammable, corrosive, explosive, or toxic

source-specific waste

• unique to particular industries.
• Examples: Sludge and wastewater from petroleum refiners and pesticide manufacturers

nonspecific-source waste

• produced by common manufacturing and industrial processes
• Solvents used for cleaning or degreasing, including those used by commercial dry cleaners

Discarded commercial chemical waste

• commercial chemical products (e.g., unused paints, pesticides, and pharmaceuticals)

types of hazardous waste

• Source-specific waste

• Nonspecific-source waste

• Discarded commercial chemical waste

household hazardous waste

common household products that have hazardous waste - batteries, computers, cleaners, nail polish, mobile phones, antifreeze

Methods used to manage hazardous waste

• Permanent retrieval storage sites

• Bioremediation

• Injection into deep wells in porous rocks

• Phytoremediation

Biomedical waste

waste that can spread infections or disease or may decompose and produce toxins and noxious odors.
• human and animal body parts and tissue, blood, used bandages and dressings, discarded gloves, and "sharps" (needles, scalpels)

Phytoremediation

Planting trees and other green vegetation to uptake contaminants
• Degrade volatiles or immobilize heavy metals

Bioremediation

• living organisms (microorganisms, plants, or fungi) break down hazardous wastes into less harmful components.
• Used to clean up spills of hazardous chemicals (oil spills)

permanent retrieval storage sites

waste is monitored to ensure they do not leak into the surrounding environment; can be recovered for reuse or for more permanent disposal; chemical processing and incineration are used to convert some hazardous waste to less toxic ash or gases.

E-waste

discarded electronic equipment such as computers, cell phones, television sets, etc.

E-waste is a source of _______

heavy metals including lead, cadmium, and mercury

radioactive waste

Materials from a nuclear reaction that emit radiation; contact with such particles may be harmful or lethal to people; therefore, the materials must be safely stored for thousands of years

• any material that is either intrinsically radioactive or has been contaminated by radioactivity

low-level radioactive waste

• contains comparatively low amounts of radioisotopes and represents the greatest volume of radioactive waste

Examples of low-level radioactive waste are __________

• radiation in hospitals and research laboratories
• contaminated clothing, filters, wiping rags, medicinal swabs, tubes, syringes, and the carcasses and tissues of laboratory animals
• residues from nuclear reactor wastewater

high-level radioactive waste

radioactive wastes that produce high levels of ionizing radiation; waste from nuclear power plants (fuel rods) and weapon labs , more dangerous, requires long-term storage & management

geologic repositories

• used fuel rods encased in special metal casks would be placed in deep caves in geologic strata that are isolated from the biosphere
• It is hoped that the metal casks and the surrounding rock will prevent the radioactive materials from leaking into the environment

Hierarchy of sustainable waste management:

• Preventing waste
• Reduce waste
• Reusing waste
• Recycling waste
• Energy Recovery
• Disposal

closed-loop recycling

when materials, such as plastic or aluminum, are used to rebuild the same product. An example of this is the use of the aluminum from aluminum cans to produce more aluminum cans.

open-loop recycling

when materials are reused to form new products

Challenges of recycling

• Economic feasibility

• Consumer demand

• Convenience plays role

(e.g., curbside collection)

Resource Conservation and Recovery Act (RCRA; 1976)

• Hazardous wastes must be tracked from the time they are generated until their final disposal
• RCRA reduces the amount of hazardous waste illegally disposed

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (1980)

• "polluter pays" principle (companies are responsible)
• Tax on industries that produce hazardous waste
• Revenues go into the "Superfund" and provided for the clean-up and remediation of closed and abandoned hazardous waste sites (hundreds of thousands of sites in the US)

Nonconsumptive water use

activities that use water and then return it to streams or aquifers
• generation of hydroelectric power
• disposal of wastewater in septic systems

Consumptive water use

a considerable amount of water evaporates into the atmosphere; much of the water is not returned to streams or aquifers
• irrigation and industrial cooling

Three major uses for water

residential, agricultural, and industrial

Industrial Water Use

• manufacture goods, disposal of wastes, generate power
• most of the water that is used in industry is used to cool power plants

Water Sources for Southern Nevada

• 90% from the Colorado River

• 10% groundwater

Groundwater

water that fills the cracks and spaces in underground soil and rock layers

watershed (drainage basin)

The land from which surface water drains into a particular river, lake, wetland, or other body of water

open watershed

the area of land drained by rivers that eventually make their way to the sea

closed watershed

inland basins that do not drain to the sea

Aquifer

saturated zone beneath the water table from which water can be extracted/pumped

• any porous geologic material that can yield water in economic quantities

• Sand or sand and gravel deposits

• Highly fractured sedimentary rocks

• primary source of drinking water in many parts of the world

water table

• underground depth where rock and sediment are completely saturated with water

recharge zone

an area in which water travels downward to become part of an aquifer

confined aquifer

A groundwater storage area trapped between two impermeable layers of rock.

unconfined aquifer

an aquifer made of porous rock covered by soil out of which water can easily flow

Aquiclude

• any porous geologic material that may yield water but not in economic quantities

• Silts and clays (mud-sized particles)

• Igneous, metamorphic, and unfractured sedimentary rocks

• Igneous & metamorphic rocks hold no water

A body of rock that will absorb water slowly, but will not transmit it fast enough to supply a well.

Porosity

percentage of the total volume of a rock or sediment that consists of open spaces.

Permeability

The ability of a rock or sediment to let fluids pass through its open spaces, or pores.

artesian well

A well in which water rises because of pressure within the aquifer

flooding

Water input exceeding capacity of stream

Which human activities intensify flooding?

• Deforestation
• Increased urbanization leads to less infiltration and more runoff (impervious surfaces: pavement, roof)

Flood control strategies

• Construction of artificial structures (levees)
• Channelization
• Pervious pavement
• Green roofs

Subsidence

the sinking of regions of the Earth's crust to lower elevations; sinking of land above an aquifer, can happen slowly

saltwater intrusion

Movement of salt water into freshwater aquifers in coastal and inland areas as groundwater is withdrawn faster than it is recharged by precipitation.

Total Maximum Daily Load (TMDL)

The amount of particular pollutants that a water body can receive from both point and nonpoint sources and still meet water quality standards.

point-source pollution

pollution that comes from a specific site

non-point source pollution

water pollution that does not have a specific point of origin

Effects of water pollution:

• Eutrophication (lakes)

• Dead zones (ocean, estuaries)

• Ocean acidification

• Ocean garbage

Water management strategies

• improved techniques for irrigating crops
• recycling of municipal and industrial water
• more efficient use of residential water

Negative impacts of dams

• sediment redistribution (create lakes with little or no water movement, sediments accumulate, decreased water storage capacity)
• Destroy ecosystems
• Reduce flow downstream (water available to floodplains, altering ecosystems)
• Water diversions (canals) move water to new locations, less flow toward sea

Channelization and artificial levees

- prevent flooding
- control flow of water
- provide floodplains for agriculture and urban development
- protect adjacent land but speed flow of water
- increase flood potential downstream

water conservation strategies

• Use recycled water (gray water)
• Non-potable purposes (irrigation, construction, etc.)
• Discontinue wasteful or inefficient practices
• Use of drip irrigation
• Desert landscaping in arid environments
• Find alternative sources
• Desalination

irrigation efficiency

the percentage of the water applied to fields that is actually used by crop plants

Alternatives to flood irrigation

surge irrigation, drip irrigation

Desalination

the removal of salt from seawater to make it usable for drinking and farming

• Distillation: boiling water and condensing the steam (pure)

• Reverse osmosis: filtering water through a selective membrane

Saving Water at Home

• install low-flow fixtures in bathrooms
• choose water-saving appliances in the kitchen and laundry
• mulch flower beds
• irrigate landscaping with soaker hoses or at the coolest time of day
• take shorter showers and turn off the tap while you brush
• Plug the sink when washing dishes
• wash only full laundry loads
• use rinse water for sprinkling houseplants or flushing toilets
• install a rain barrel for your outdoor irrigation needs
• wash your car on the lawn.

Riparian Water Rights

• derived from English common law
• all landowners with property adjacent to a body of water have a right to make reasonable use of it (defined by each state, domestic water use, swimming, boating, and fishing)
• Rights can be sold or transferred only to adjacent landowners, and water cannot be transferred out of a watershed.

prior appropriation water rights

Water law in which the person who first uses a quantity of water from a water source for a beneficial use has the right to continue to use that quantity of water for that purpose indefinitely. Rights to the remaining water are similarly allocated to subsequent users. When water runs short, users with the earliest appropriation get their full allocation; later users may get no water.

Water Conservation Law - US

• 1948 Water pollution control act: first comprehensive national law to manage water quality

• 1973 Endangered Species Act: protects flow of water in rivers and streams (habitats)

• 1972 Clean Water Act

• 1987 Water Quality Act

Based on the definition, a mineral must be:

• solid

• inorganic (or identical to an inorganic mineral)

• natural (or made in a way that mimics nature, has been found in nature)

• chemically homogeneous (that is, the mineral contains the same chemicals throughout; one chemical formula describes the mineral)

• crystalline (the atoms in a mineral are arranged in an orderly and repeating pattern)

Beneficiation

process of extracting the desired mineral or element from ore

Mineral resources

minerals or rocks mined from Earth and used in products we use daily

rock

A naturally occurring solid mixture of one or more minerals or organic matter

ore

a rock that contains a large enough concentration of a mineral making it profitable to mine

metal

an element that is shiny and that conducts heat and electricity well, opaque, malleable

Uses of nonmetallic minerals

• Building materials: Sand and gravel; Clay (ceramics)

• Decorative rocks: limestone, granite, marble

• Industrial use

• Agricultural use: Phosphate for fertilizer

strategic metals and minerals

Materials that a country cannot produce itself, but are essential... so they have to trade

Addressing limited mineral availability

• Continued exploration (find more)

• Find a substitute

• Conserve and increase efficiency

• Recycle

Mining

systematic removal of rock, soil, or other material to remove the minerals of economic interest

Economically valuable metals

copper, iron, lead, gold, aluminum

Mineral recovery steps

• Locating it (Exploration)

• Obtaining it (Extraction)

• Concentrating it (Beneficiation/Smelting/Refining)

• Cleaning up during/afterward (Remediation/Reclamation/Mine Closure)

enrichment factor

ratio of the metal concentration needed for an economic ore deposit over the average abundance of that metal in Earth's crust

exploration

• First phase in the mining process
• combination of methods to find suitable mining locations and determine the location, size, depth, and the orientation/trend of the deposit

Factors affecting the financial viability of extraction

– Concentration of mineral (ore grade)

– Depth to ore

– Technology available

– Potential environmental impact

– Transportation and/or water needs

– Regulations

– Politics and/ or political boundaries

– Social norms

– Human health concerns

alloy

metal is mixed, melted, or fused with another metal or nonmetal substance

Smelting

The process by which ore is melted to separate the useful metal from other elements.

flotation

This process mixes the slurry with a reagent and adds bubbles. Due to the (specifically selected) chemistry, the desired minerals will attach to the bubbles and both will float to the top where they can be skimmed off and the mineral can be further concentrated

Leaching

• use of chemicals (such as sulfuric acid or sodium cyanide) to dissolve the desired metals and transport them, in solution, to a collection area
• desired metals are precipitated out of that solution
takes place in a vat after milling or instead of milling (pre- or post-crushing) in large outdoor piles (heaps) or even within the ground itself (in-situ)

tailings

waste product from the flotation process; pumped into impoundments called tailing ponds, which are usually downhill from the mill (to use gravity to help transport the material)

Social effects of mining

• Mine blasting cracks foundations and walls
• Floods and rockslides affect properties
• Overloaded coal trucks speed down rural roads
• Coal dust and contaminated water cause illness
• Local politicians do not help
• High-efficiency mining reduces the need for workers

Reclamation processes

• Backfilling
• Recontouring
• Replacement of top soil
• Reseeding or Revegetation
• Replace overburden

Reclamation

restoration of land to either natural conditions or another useful purpose, often involves stabilizing soils and slopes in an area through grading and use of vegetation. Usually soil treatment, or addition of new soil, is necessary prior to revegetation

Remediation

process of fixing, removing, or counteracting an environmental problem. In mining, often the water leaving the mine must be remediated before being released back into the natural system. Sometimes the soil itself must be relocated to specialized repositories.

General Mining Act of 1872

• Encourages metal and mineral mining on federal land

• Any citizen or company can stake a claim on any public land open to mining for $5 per acre

• The public gets no payment for any minerals found.