Final study terms (water pollution)

Question 1

how does water pollution happen?

Answer 1

• water pollution occurs when discharges of energy or materials degrade water

Question 2

How is water pollution measured

Answer 2

Water pollution is measured by the concentration of pollutants in the water body and their effects on other water uses

Question 3

What are some water pollutants of concern?

Answer 3

• Oxygen-demanding wastes
• nutrients
• thermal pollution
• toxic material
• acidification
• pathogens

Question 4

What is one of of the most important measures of the quality of water?

Answer 4

DISSOLVED OXYGEN (D.O.) present

Question 5

What is eutrophication?

Answer 5

A process whereby water bodies receive excess nutrients that stimulate excessive plant growth
This enhanced plant growth, often called an algal bloom, reduces dissolved oxygen in t he water when dead plant material decomposes and can cause other organisms to die

Question 6

What are some causes of thermal pollution?

Answer 6

• Power plants creating electricity from fossil fuel and water used as cooling agent
• Deforestation of shoreline
• soil erosion

Question 7

What are some toxic materials that can affect the health of aquatic organisms?

Answer 7

heavy metals (heavy metals only bad when they show up in large amounts due to industrialization)
pesticides (herbicides, insecticides, fungicides, nematicides, rodenticides)
volatile organic compounds (vinyl chloride, tetrachloroethylene PCE)

Question 8

What are some effects of acidification?

Answer 8

Acid deposition (acid rain and acid particles)
Minerals (mercury, aluminum, lead become more soluble and therefore more harmful in low pH environments)

Question 9

What are pathogens and how do they affect water quality?

Answer 9

Pathogens are disease-causing bacteria, viruses and protozoa, usually from human sewage
- Bacteria (cholera, dysentery, typhoid)
- Viruses (hepatitis)
- Protozoa (dysentery, giardiasis)
- Helminth (parasitic worms)

Question 10

what are the steps of wastewater treatment?

Answer 10

***depends of effluent discharge requirements (ocean, inland stream, environmentally sensitive lakes, streams, estuaries, groundwater)
- Preliminary treatment
- Primary treatment
- Secondary treatment
- Advanced (tertiary) wastewater treatment

Question 11

Classification of preliminary treatment (for wastewater)

Answer 11

pumping, screening, grit removal

Question 12

Classification of primary treatment (for wastewater)

Answer 12

sedimentation (a portion of suspended solids and organic matter removed approx. 30% BOD and 60% TSS

Question 13

Classification of secondary treatment (for wastewater)

Answer 13

Further treatment of effluent from primary treatment for residual organic matter and suspended solids removal approx. 90% BOD and TSS
Typically biological reactors (i.e. activated sludge process, trickling filter)

Question 14

Classification of advanced (tertiary) wastewater treatment (for wastewater)

Answer 14

Effluent from secondary treatment may be further treated to reduce specific chemical constituents in wastewater (phosphorous, nitrogen) if discharged to environmentally sensitive estuaries

Question 15

what are the mechanisms that affect DO in rivers?

Answer 15

oxygen demanding wastes removes DO
photosynthesis adds DO during the day
plants remove DO at night
respiration of organisms living in water and sediments removed DO
tributaries add their own DO inputs and DO demands
rising water temps reduces oxygen solubility in water
winter ice blocks atmospheric recharge

Question 16

Describe the lake water quality for the season of winter

Answer 16

lake is thermally stratified with cold (approx 0 deg) water near the surface and warmer (2-4 deg) denser waters near the bottom

Question 17

Describe the lake water quality for the season of spring

Answer 17

As the surface waters warm toward 4 deg in spring, they become denser and sink, bringing colder waters to the surface to warm
the process of mixing by convection, aided by wind energy, circulates the water column, leading to an isothermal condition termed spring turnover

Question 18

Describe the lake water quality for the season of summer

Answer 18

As lake waters continue to warm above 4 deg, the lake thermally stratifies. Surface waters are significantly warmer and less dense than the lower waters during summer stratification

Question 19

Describe the lake water quality for the season of fall

Answer 19

The input of solar energy decreases and heat is lost from the lake more rapidly than it is gained.
As surface waters cool, they become denser, sink, and promote circulation through convection, aided by wind, this phenomenon called fall turnover again leads to isothermal conditions

Question 20

What is BOD and how is it created?

Answer 20

BOD is biochemical oxygen demand and is created by oxygen demanding organic wastes decaying in the water body