Natural Resources: Water Quality and Conservation (Unit 8)

Question 1

What percentage of the Earth’s surface is covered by water? Why is water considered a universal solvent? How does this make it susceptible to pollution?

Answer 1

Water covers nearly 71 percent of Earth’s surface. Water is a universal solvent, which means it dissolves more substances than any other liquid. This characteristic of water makes it susceptible to pollution.

Question 2

Water Pollution Definition

Answer 2

harmful substances contaminating a stream, river, lake, ocean, aquifer, or other body of water, lowering water quality and making the water toxic

Question 3

Groundwater Definition

Answer 3

water stored in the cracks and spaces of underground rock

Question 4

Surface Water Definition

Answer 4

bodies of water on the surface of Earth such as oceans, rivers, and lakes

Question 5

True or False: Because Earth has a limited freshwater supply, water pollution can be devastating.

Answer 5

True

Question 6

Most water pollution is the result of what?

Answer 6

Most water pollution is the result of human activities.

Question 7

How does groundwater get polluted?

Answer 7

Groundwater, or the water stored in the cracks and spaces of underground rock, gets polluted when contaminants seep down into the aquifer (an underground water reservoir). Once an aquifer is polluted it can be very difficult and costly to make the water safe again.

Question 8

How does surface water get polluted?

Answer 8

Surface water includes bodies of water on Earth’s surface such as oceans, rivers, and lakes. Surface water gets contaminated when biological, chemical, and physical contaminants are dumped or runoff into water supplies. Understanding the source or causes of these pollutants can help protect water resources.

Question 9

What is point source pollution?

Answer 9

Point source pollution is pollution that comes from a known and specific location, such as pipes from a factory or treatment plant or a leaking storage tank.

Question 10

What is nonpoint source pollution?

Answer 10

Nonpoint source pollution is pollution that does not have a specific point of origin. These contaminants are difficult to trace to a specific site. Runoff carries nonpoint source pollution from places such as cities, farms, or feedlots.

Question 11

How is runoff nonpoint source pollution?

Answer 11

Runoff can carry waste, oil, and debris from city streets and it can carry animal waste, pesticides, or fertilizers from feedlots, farms, and lawns.

Question 12

Point Source Pollution Definition

Answer 12

pollution that comes from a known and specific location

Question 13

Nonpoint Source Pollution?

Answer 13

pollution that does not have a specific point of origin

Question 14

What causes algae to form?

Answer 14

Occurs when there are too many nutrients, warm water temperatures, or reduced water flow.

Question 15

What are the effects of algal blooms on the water and the environment?

Answer 15

Harms aquatic life by clogging fish gills, reducing oxygen levels, and smothering streams, lake beds, and submerged vegetation; Some algae blooms can produce poisons that harm humans, pets, wildlife, and livestock when swallowed.

Question 16

What are ways to reduce algal blooms?

Answer 16

Reduce algae blooms by using fertilizer sparingly, regularly checking and pumping septic tanks, and properly storing and disposing of animal and plant waste.

Question 17

What causes dioxins to form?

Answer 17

Formed by burning trash or leaded gasoline and from manufacturing some pesticides.

Question 18

What are the effects of dioxins?

Answer 18

Increases cancer risk and may harm the immune system, hormone levels, and fetal development.

Question 19

What are ways to reduce contamination by dioxins?

Answer 19

Exposure to dioxins occurs largely through the food eaten; Pay attention to local fishing advisories for fish you catch and eat yourself.

Question 20

What causes mercury to be emitted?

Answer 20

Released into the air by coal-fired power plants, it is washed into waterways; Spills and improper treatment can increase mercury levels in water.

Question 21

What are the effects of mercury?

Answer 21

Mercury can build up in fish, which then poses health risks to people and animals that eat them.

Question 22

What are ways to reduce and prevent the emission of mercury?

Answer 22

Purchase mercury-free products and correctly dispose of products that contain mercury.

Question 23

What causes nutrients (nitrogen and phosphorus) to go into water supplies?

Answer 23

Present in fertilizers and can get washed up in waterways with agricultural runoff.

Question 24

What are the effects of the emission of nutrients (nitrogen and phosphorus)?

Answer 24

Causes harmful algae blooms; can also create low oxygen conditions that harm fish and other aquatic life.

Question 25

What are ways to reduce the emission of nutrients (nitrogen and phosphorus)?

Answer 25

Reduce the use of lawn and plant fertilizers.

Question 26

What causes oil and grease to enter into the water supply?

Answer 26

Results from leaks and spills occurring on land and on the water.

Question 27

What are the effects of oil and grease?

Answer 27

Oil and grease can be toxic to plants and animals even in small amounts.

Question 28

What are ways to reduce and prevent the emission of oil and grease?

Answer 28

Dispose of car oil and paints properly and never in storm sewers and drains, clean up spilled oil and grease with absorbent towels instead of hosing them into the street, and fix oil leaks from vehicles right away.

Question 29

What causes pathogens to enter the water supply?

Answer 29

Enter waters through septic tank leaks, sewage discharges, farm and feedlot manure runoff, boat discharges, and pet and wildlife waste.

Question 30

What are the effects of pathogens?

Answer 30

People can become ill by eating contaminated fish or shellfish, or swimming in waters with high levels of these microbes.

Question 31

What are ways to reduce and prevent the emission of pathogens?

Answer 31

Never dump animal or boat waste in a waterway, fix leaky septic tanks, pick up pet waste, and don’t apply manure close to shorelines or drainage ditches.

Question 32

What causes pesticides to enter into the water supply?

Answer 32

Enter waters through stormwater or irrigation runoff, discharge from industries, wastewater treatment plants.

Question 33

What are the effects of pesticides?

Answer 33

Pesticides can affect the health of aquatic insects, fish, plants, and animals.

Question 34

What are ways to reduce or prevent the emission of pesticides?

Answer 34

Use insecticides and herbicides in proper doses—well away from waters or drainage ditches and only on days without any storms or rains—and dispose of waste properly.

Question 35

What causes salts to enter into the water supply?

Answer 35

Used for de-icing roads and gets washed into waterways; also comes from industrial wastewater.

Question 36

What are the effects of salts?

Answer 36

Toxic to freshwater plants and animals; makes water unusable for drinking, irrigation, and livestock, and harms the roots of plants.

Question 37

What are ways to prevent and reduce the emission of salts?

Answer 37

Minimize the use of de-icing salts to avoid runoff into waterways, storm drains, and ditches.

Question 38

What causes trash to enter into the water supply?

Answer 38

Litter left on sidewalks, streets, yards, or other open areas carried by rainwater to storm drains that discharge into waterways.

Question 39

What are the effects of the pollutant trash?

Answer 39

Trash can be contaminated with toxins or bacteria, and it can harm fish and wildlife that eat it or become entangled in it.

Question 40

What are ways to prevent and reduce the emission of trash into the environment?

Answer 40

Properly dispose of trash, avoid littering in or near waterways, prevent trash from being blown away, and pick up visible trash in and near waterways.

Question 41

For over a century, what was the Cuyahoga River used as by the city of Cleveland? How many fires did this cause? When the River caught on fire again on June 22, 1969, which movement made the country finally take notice? How did the first photographs of Earth change people’s perception on the planet? What did Rachel Carson’s “Silent Spring” discuss, made in 1962?

Answer 41

For over a century, the Cuyahoga River was used by the city of Cleveland as a dumping ground for chemical and sewage wastes. It was such a problem that the oil slicks on the river caught fire 13 times. However, when the river caught fire on June 22, 1969, the country finally took notice. This is because the cultural revolution of the 1960s and 1970s included a new awareness and appreciation of the environment. The first photographs of Earth taken by astronauts inspired people to view the planet as a small, finite resource. In 1962, books like Silent Spring by Rachel Carson highlighted the damage caused by the irresponsible use of toxic chemicals. People began to wonder how things could be changed and if the damage to the environment could be undone.

Question 42

About how many gallons of sewage does the United States produce everyday?

Answer 42

34 billion

Question 43

Prior to the Clean Water Act (CWA), how was wastewater treated and disposed of?

Answer 43

Prior to the Clean Water Act (CWA), wastewater could be legally dumped into surface waters with little or no treatment. Industrial wastewater was also dumped directly into the nearest body of water. These practices led to situations like the Cuyahoga River fire.

Question 44

In 1970, President Nixon signed the National Environmental Policy Act (NEPA), which led to the creation of which agency? Why was the Clean Water Act created? Under the Clean Water Act, what does the Environmental Protection Agency have the right to do? What did the Clean Water Act outlaw? What did the Clean Water Act fund?

Answer 44

In 1970, President Nixon signed the National Environmental Policy Act (NEPA), which led to the creation of the Environmental Protection Agency (EPA). The Clean Water Act was created in order to regulate water pollution. It gave the EPA the authority to set standards for industrial wastewater. It made it illegal for anyone to discharge pollutants without a tightly controlled permit. The CWA also funded the construction of sewage treatment plants to help reduce municipal point-source pollution.

Question 45

Clean Water Act (CWA) Definition

Answer 45

regulates discharges of pollutants into U.S. waters and regulates the quality standards for surface water

Question 46

Environmental Protection Agency (EPA) Definition

Answer 46

a federal agency of the United States government that sets and enforces guidelines that protect the environment

Question 47

What environmental crisis/campaign happened on September 27, 1962?

Answer 47

September 27, 1962: Rachel Carson’s Silent Spring detailed the damage done to wildlife through the overuse of pesticides.

Question 48

What environmental crisis/campaign happened on January 28, 1969?

Answer 48

January 28, 1969: A massive oil spill occurred off the coast of Santa Barbara, CA.

Question 49

When was Earth day first celebrated in the United States?

Answer 49

April 22, 1970

Question 50

Going into effect on January 1, 1970, what was the National Environmental Protection Act?

Answer 50

January 1, 1970: The National Environmental Policy Act (NEPA) went into effect. The act requires that any project funded by a federal agency must include an environmental assessment. There must also be an environmental impact statement, describing how the project could affect the ecosystem.

Question 51

Being founded on December 2, 1970, what was the Environmental Protection Agency (EPA)?

Answer 51

December 2, 1970: The Environmental Protection Agency (EPA) was officially founded. The EPA has power as a regulatory agency. It can create and enforce standards for air and water quality. It can also regulate specific pollutants.

Question 52

Going into effect on October 18, 1972, what was the Clean Water Act?

Answer 52

October 18, 1972: The Clean Water Act (CWA) was created to remediate and protect surface waterways. The CWA regulates point sources of pollution. It also provides funds for municipalities to build or upgrade sewage treatment plants.

Question 53

Going into effect on December 16, 1974, what was the Safe Drinking Water Act (SDWA)?

Answer 53

December 16, 1974: The Safe Drinking Water Act (SDWA) was enacted. The SDWA ensures that drinking water is safe. It requires drinking water be monitored for microorganisms, disinfectants, disinfectant by-products, inorganic and organic chemicals, and radionuclides. The SDWA monitors groundwater and public drinking water sources, as well as drinking water on board airplanes. However, it does not monitor bottled water. That is left up to the Food and Drug Administration.

Question 54

Enacted on December 11, 1980, what was the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)?

Answer 54

December 11, 1980: The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) was enacted in 1980. It provides a Superfund to clean up sites contaminated with hazardous waste.

Question 55

What are the costs of environmentally regulations?

Answer 55

Environmental regulations do have costs. The costs include businesses having to find a way to safely dispose of wastes, instead of simply discharging them into the water or ground. Because the CWA made point-source pollution illegal, the EPA can fine businesses that break the law.

Question 56

What was the cost of the Deepwater Horizon oil spill in 2010? What did the oil company’s fine help pay for?

Answer 56

• $2.5 billion hit to Louisiana’s fishing industries
• $3 billion hit to Florida’s tourism industry
• $20 billion fine paid by BP

(The oil company’s fine helped pay for damages to local fishing and tourism industries. The fine also helped to cover the costs of rehabilitating the ecosystem.)

Question 57

What do supporters of the Clean Water Act argue, concerning the interconnection of water? What are the economic benefits of having cleaner water?

Answer 57

Supporters of the CWA argue that all water is connected in the water cycle. Therefore, wastes that are discharged into ditches or ponds will run into larger bodies of water over time. Supporters also point to the economic benefits of having cleaner water:

• Municipalities save money on cleaning water for drinking when the water is less polluted.
• Tourism earnings increase when the water is clean enough to swim or fish in.
• Waterfront property usually has a higher value when the water is cleaner.

Question 58

How is the funding of projects and treatment plants an advantage of the Clean Water Act? What is the State Revolving Fund, added to the Clean Water Act in the late 1980s?

Answer 58

Another major benefit of the CWA is that by the late 1990s, it provided more than $62 billion in grant money for municipalities to construct or expand their treatment works. In the late 1980s, the CWA was amended to include the State Revolving Fund, which has provided over $126 billion in loans to states. As the money is repaid, it returns to the fund where it can be loaned to fund additional projects.

Question 59

How do statistics show the impact of the Clean Water Act and the Safe Drinking Water Act?

Answer 59

Prior to the CWA, only about one-third of U.S. waterways were safe for swimming and fishing; now nearly two-thirds of waterways qualify. While wetlands are still being lost, the rate has dropped from 500,000 acres per year to 60,000 acres per year. Now, about 93% of water systems for U.S. communities meet all the health-based standards of the Safe Drinking Water Act (SDWA). This is an increase of over 14% since 1993.

Question 60

Safe Drinking Water Act Definition

Answer 60

act passed in 1974 that ensures drinking water is safe by requiring drinking water be monitored for microorganisms, disinfectants, disinfectant by-products, inorganic and organic chemicals, and radionuclides

Question 61

What is one weakness of the Clean Water Act and the Safe Drinking Water Act, concerning nonpoint-source pollution?

Answer 61

One of the weaknesses of the CWA and SDWA is that, while point-sources of pollution have become much more strictly regulated, not enough has been done to address nonpoint-source pollution such as city and farm runoff. Areas that are heavily populated, used for livestock, or where pesticides and fertilizers are applied all produce a great deal of runoff pollution that ends up in rivers, lakes, and oceans.

Question 62

Remember: While it’s true that most municipalities in the U.S. now treat their sewage wastewater, overflows do still happen resulting in raw sewage being leaked or dumped into waterways. This is largely due to how sewers developed through history. Initially, before flush toilets and running water, sewers were only designed to handle stormwater to reduce flooding in streets. As plumbing was installed in housing, sewage drained into existing stormwater sewers. Up until the 1970s, in many places the combination of stormwater and household sewage was simply dumped into a local body of water. Now, however, nearly all combined sewage wastewater is sent to the local publicly owned treatment works (POTW) where sewage sludge is separated out. (Sludge is an unpleasant combination of fecal matter, toilet paper, and various solids that have been flushed or washed into storm drains.) The wastewater is then cleaned before being reintroduced to local waterways. However, because populations have grown dramatically, the combined sewer systems must now handle far more wastewater than they were designed for. During heavy rains, this leads to overflows.

Answer 62

While it’s true that most municipalities in the U.S. now treat their sewage wastewater, overflows do still happen resulting in raw sewage being leaked or dumped into waterways. This is largely due to how sewers developed through history. Initially, before flush toilets and running water, sewers were only designed to handle stormwater to reduce flooding in streets. As plumbing was installed in housing, sewage drained into existing stormwater sewers. Up until the 1970s, in many places the combination of stormwater and household sewage was simply dumped into a local body of water. Now, however, nearly all combined sewage wastewater is sent to the local publicly owned treatment works (POTW) where sewage sludge is separated out. (Sludge is an unpleasant combination of fecal matter, toilet paper, and various solids that have been flushed or washed into storm drains.) The wastewater is then cleaned before being reintroduced to local waterways. However, because populations have grown dramatically, the combined sewer systems must now handle far more wastewater than they were designed for. During heavy rains, this leads to overflows.

Question 63

Biodiesel Definition

Answer 63

a fuel similar to fossil diesel fuel that is derived from organic sources such as plant or animal oils

Question 64

What is the Cuyahoga River like today?

Answer 64

In the 1960s, it was a fire hazard with little or no wildlife. Today, the river has been repopulated with fish that require clean water to live, such as the steelhead trout and northern pike. While fishing is now permitted in much of the Cuyahoga River, advisories are still in place regarding fish caught from the river and its tributaries. Officials warn against eating more than one meal a week of fish caught from the river because of high levels of harmful chemicals.

Question 65

What do ecosystems facilitate? Why is biodiversity important?

Answer 65

Ecosystems regulate climate processes; break down wastes and recycle nutrients, filter and purify water; buffer against flooding; maintain soil fertility; purify air; and provide natural resources and, of course, food. Biodiversity is a fundamental part of ecosystem health. Reduction in biodiversity can lead to the collapse of these ecosystems on which people depend. Understanding and tracking water quality is an essential part of managing water ecosystems’ resources and maintaining biodiversity.

Question 66

In water ecosystems, why is the quality of the water so important? What do scientists use to determine the overall health of a water ecosystem?

Answer 66

In water ecosystems, the qualities of the water itself are central to defining the health of the whole ecosystem. The water must provide the nutrients for aquatic life. Too high a level of nutrients leads to the overgrowth of algae, plankton, and other microorganisms, which can have a serious negative effect on other aquatic life. To determine the overall health of a water ecosystem, scientists look for water conditions that do not promote eutrophication or promote a toxic environment for aquatic life.

Question 67

Eutrophication Definition

Answer 67

excessive nutrients in a water body causing overgrowth of algae, plankton, and other microorganisms

Question 68

What are the four parameters water quality is measured by?

Answer 68

Turbidity, Temperature, pH, and Dissolved Oxygen?

Question 69

What is turbidity?

Answer 69

Turbidity is a measure of the relative clarity of the water.

Question 70

How is turbidity measured?

Answer 70

Turbidity is measured using a disc with contrasting black and white sections, which is called a secchi disc. The disc is lowered into the water until the black and white sections cannot be clearly distinguished. The higher the depth measurement (usually feet and inches), the less turbid the water.

Question 71

Why is measuring turbidity important?

Answer 71

Water that is highly turbid will absorb heat (see effects of temperature) and block sunlight. Underwater plants are dependent on sunlight for photosynthesis, so blocking the light causes these plants to die off. Many aquatic organisms depend on the plants for oxygen, food, and shelter.

Question 72

How is temperature measured in a water ecosystem?

Answer 72

Temperature is measured in degrees F or C. In a body of water, temperatures will vary based on the depth of the sample.

Question 73

Why is measuring the temperature of water ecosystems important?

Answer 73

Aquatic life of various types have optimal temperatures for survival. Temperatures that are either too warm or too cold will cause loss of aquatic life and diversity. Temperature also affects the solubility of toxic chemicals and heavy metals. Many toxic chemicals and heavy metals will better dissolve in warmer water. Warmer temperatures also increase the metabolic rate of organisms. Increasing the metabolic rate of plants increases their need for oxygen for photosynthesis. Increasing the metabolic rate of other aquatic organisms can weaken them and leave them subject to parasites and disease.

Question 74

What is pH?

Answer 74

pH is a measure of how acidic or basic (alkaline) the water is.

Question 75

How is pH measured?

Answer 75

pH is cited as a figure between 0 and 14 defining how acidic or basic a body of water is along a logarithmic scale. The lower the number, the more acidic the water is. The higher the number, the more basic it is. A pH of 7 is considered neutral.

Question 76

Why is measuring pH important?

Answer 76

At either extreme, aquatic organisms die. pH also affects the solubility and toxicity of chemicals and heavy metals in the water. Also, the solubility of phosphorus and nitrogen is affected by variations in pH, making these nutrients more available for plant growth. This means that pH levels that promote phosphorus and nitrogen availability to plants can be part of a chain of effects leading to eutrophication.

Question 77

What is dissolved oxygen and what are its sources?

Answer 77

Though oxygen is one of the atoms in a water molecule, this oxygen is not available for living aquatic animals. They need the oxygen molecule (O2) just like we do. Oxygen can be dissolved in water just like carbon dioxide is dissolved in soft drinks. You don’t see it (until you see the CO2 bubbles), but it is jostling around among the water molecules. Dissolved oxygen gets into the water primarily from the atmosphere, secondarily from groundwater. Faster flowing water will have higher levels of dissolved oxygen than stagnant water.

Question 78

How is dissolved oxygen measured?

Answer 78

There are different testing methods for determining how much dissolved oxygen is in a water sample. Whichever test method is used, the final reading will be the milligrams of oxygen per liter. Dissolved oxygen in a waterway may measure in a range from 0 mg/l to 18 mg/l. The amount of dissolved oxygen in the water will be inversely related to the temperature. The warmer the water, the less dissolved oxygen it will contain.

Question 79

Why is measuring dissolved oxygen important?

Answer 79

Dissolved oxygen is essential for aquatic life. Plants need dissolved oxygen for photosynthesis. Animals breathe the dissolved oxygen in the water, not the oxygen from water molecules. One result of eutrophication is bacteria from decaying organic matter consuming all of the dissolved oxygen, resulting in death of aquatic life.

Question 80

Remember: The inside of an ultrafiltration membrane system at a water treatment plant shows hollow fiber bundles bunched together. The ultrafiltration membranes are semipermeable and remove almost all of the solids from water.

Answer 80

The inside of an ultrafiltration membrane system at a water treatment plant shows hollow fiber bundles bunched together. The ultrafiltration membranes are semipermeable and remove almost all of the solids from water.

Question 81

True or False: Distillation, filtering, boiling, and adding chlorine are some of the most common water purification methods. These small- to medium-scale methods can be used in households, labs, and other facilities.

Answer 81

True

Question 82

True or False: According to the United Nations World Water Development Report, 80% of the world’s wastewater flows back into the environment without being reused or treated.

Answer 82

True

Question 83

What is the water filtration practice of distillation?

Answer 83

• This purifies water by a process of heating and cooling.

• It removes a broad range of contaminants. As the water
boils, most contaminants remain behind in the liquid.

• The process removes oxygen and minerals from water.
• It requires large amounts of energy and is very costly.

• Equipment must be carefully maintained to ensure
purity.

• Some contaminants can be carried into the water vapor
and can be found in the distilled water. Organics such
as herbicides and pesticides cannot be removed.

• Distilled water has a lower pH and can also be very
acidic.

• Distilled water is mainly used for industrial processes.

Question 84

What is the water filtration practice of deionization?

Answer 84

• This removes ions and dissolved inorganics through an ion exchange process.
• It does not remove particles, organics, or microorganisms such as bacteria.
• Over the long term, deionization has a high operating cost.

Question 85

What is the water filtration practice of carbon absorption?

Answer 85

• This purifies water by using porous activated carbon (in granular or powder form).
• It involves physical and chemical processes.

• It removes organic compounds, most chemicals and gases, and some
microorganisms.

• It does not usually remove total dissolved solids, hardness, or heavy
metals such as lead. Some specialized carbon filters do remove things
such as lead or asbestos.

• This helps improve the taste and odor of water.

• When using the granular activated carbon, the carbon medium can be
cleaned and reused.

• It has a lower cost than other filtration types and is commercially
available to anyone.

• When the adsorption medium reaches its capacity, it has to be replaced.

• Carbon adsorption can be reversed; compounds can desorb after
capacity is reached.

Question 86

What is the water filtration practice of reverse osmosis?

Answer 86

• The process uses pressure to reverse the flow of water in a natural process of osmosis. Water passes from a more concentrated solution to a more dilute solution through a semi-permeable membrane filter.
• The pore size for a reverse osmosis filter is 0.0001 micron.
• This removes protozoa, bacteria, viruses, and common chemical contaminants such as sodium, copper, and lead.
• It has a low cost and does not require much maintenance
• This removes beneficial minerals and changes the pH of water, making it more acidic.
• Small pore size limits the flow rate.

Question 87

What is the water filtration practice of ultraviolet radiation?

Answer 87

• This process uses ultraviolet light to disinfect pre-filtered water or reduce the amount of bacteria found in the water.
• It is highly effective at removing protozoa and bacteria.
• As there is no filter, heavy metals cannot be removed.
• It is inefficient at removing chemical contaminants
• This can only be used with pre-filtered water or the particles can block UV light.

Question 88

What is the water filtration practice of ultrafiltration?

Answer 88

• This is a process by which water moves through a physical medium that absorbs liquids, gases, and other matter that adhere to the pores of the medium.
• It effectively removes organics, such as protozoa, viruses, bacteria.
• It does not remove most dissolved organics or common chemicals, such as lead, radium, or asbestos.
• This process helps filter and produce a higher quality of water using the least amount of energy.

Question 89

What is the objective of water treatment? How do processes used to treat water vary?

Answer 89

Water treatment plants use several filtration methods that involve physical, chemical, and biological processes. The objective of water treatment is to make the water environmentally safe and produce solid waste that can be reused or disposed of in landfills. Processes used in water treatment and sanitation of water vary depending on the source and kinds of water. Municipal water is treated differently from industrial water as contaminants vary.

Question 90

What are the two basic stages in the treatment of waste?

Answer 90

The two stages are primary and secondary. In the primary stage, solids are allowed to settle and then removed from wastewater. The secondary stage uses biological processes to further purify wastewater.

Question 91

What is the importance of a grit chamber?

Answer 91

In a grit chamber, cinders, sand, and small stones settle to the bottom. A grit chamber is particularly important in communities with combined sewer systems where sand or gravel may wash into sewers along with stormwater.

Question 92

What is sludge?

Answer 92

Sludge is the mass of solids produced in the primary stage.

Question 93

How is activated sludge better than trickling filters?

Answer 93

The activated sludge process speeds up the work of the bacteria by mixing new sewage with air and sludge filled with bacteria. After the sewage leaves the settling tank in the primary stage, it is pumped into an aeration tank, where it is mixed with air and sludge loaded with bacteria and allowed to remain for several hours. During this time, the bacteria break down the organic matter into harmless by-products. This sludge can also be reused again and again.

Question 94

Why is chlorine added?

Answer 94

Chlorine is added to disinfect, to kill pathogenic bacteria, and to reduce odor.

Question 95

What are some advanced wastewater treatment techniques and why are they needed?

Answer 95

Examples of advanced wastewater treatment techniques are filtration, carbon adsorption, distillation, and reverse osmosis. These techniques are being used to remove pollutants such as heavy metals, chemical compounds, and toxic substances.

Question 96

What caused the water to change and suddenly become unsafe in Flint, Michigan?

Answer 96

Flint switched from the Detroit Water and Sewage Agency to taking water from the Flint River. Officials decided to not sufficiently treat the water and it began to cause corrosion in the pipes.

Question 97

How does lead get into water?

Answer 97

Lead gets into water by leaching (or seeping) out of old plumbing pipes made of lead. The more corrosive the water, the more lead leaches out.

Question 98

What is the Environmental Protection Agency’s (EPA) limit on lead in water? What levels of lead were detected in households in Flint?

Answer 98

The EPA has set a limit for lead at 15 parts per billion for drinking water. In Flint, lead was found at levels around 104 parts per billion, nearly seven times higher (one household had levels up to 13,200 parts per billion) .

Question 99

What are some problems associated with lead poisoning in children?

Answer 99

Lead poisoning can lead to a number of problems including developmental delays, learning disabilities, irritability, decrease in appetite, fatigue, abdominal pain, and vomiting.

Question 100

How did city and state officials respond to reports of high lead levels?

Answer 100

Officials initially denied that there were high lead levels and did not warn residents about the risks.