Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
List the major pollutant categories (four) that are produced by each of the four principal sources of wastewater.
|
Oxygen-demanding materials (organic matters), nutrients (N, P), pathogens (bacteria, protozoa), suspended solids.
|
|
|
List the two nutrients of primary concern with respect to a receiving body of water
|
Nitrogen and Phosphorus
|
|
|
Define biochemical oxygen demand.
|
BOD is a measurement of biodegradable organic materials in water by measuring the change in oxygen concentration over time.
|
|
|
Explain the procedure for determining BOD and specify the nominal values of temperature and time used in the test.
|
Water sample containing organic matter is placed in a closed container and inoculated with bacteria. Oxygen consumption is measured over 5 or 7 days at temperature 20 degrees.
|
|
|
List three reasons why the BOD rate constant may vary.
|
- nature of waste (degradation occurs slowly or rapidly)
- ability of organism to utilize waste - temperature of water changes throughout the year |
|
|
List the most important pollutants affecting water quality in rivers and explain how each affects the water quality.
|
Nitrogen: NH3-N is toxic to fish, low concentration of NH3 and NO3- serve as nutrients for excess growth of algae, conversion of NH4+ to NO3- requires large DO.
Phosphorus: Vital nutrient for algal growth -> algal death produces much OM -> low DO -> fish die |
|
|
List the most important pollutant affecting water quality in lakes and explain how it affects the water quality.
|
Phosphorus contributes to eutrophication of lake (more ability to support food chain by cycling of nutrient) by increasing algae growth.
|
|
|
Sketch and compare the epilimnion and hypolimnion with respect to the following: location in the lake, temperature, and oxygen abundance (DO).
|
Epilimnion is the upper part of the lake and hypolimnion is the bottom part of the lake. In summer, epilimnion is warm and aerobic due to well mixing. Hypolimnion is cold, not mixed, thus anaerobic. In the fall, the surface water cools down and becomes more dense, so turnover occurs. Turnover stops when hypolimnion temperature reaches 4 degrees where water is most dense. In winter, epilimnion part temperature is zero.
|
|
|
Explain the difference between eutrophic and oligotrophic lakes in terms of productivity and water quality.
|
Eutrophic lakes: high productivity (nutrients), turbid because of algae growth, oxygen depletion due to decomposition of algae.
Oligotrophic: low productivity, clear water. |
|
|
Explain the process of eutrophication.
|
Lakes become more shallower and productive because of nutrient introduction and cycling of nutrient. Strengthened by algae growth and phosphorus abundance. It is a naturally occuring process, but it can be enhanced by human activity.
|
|
|
Name the limiting nutrient and explain why it is a limiting nutrient.
|
Phosphorus: it is not obtainable from the atmosphere like nitrogen or the natural water supply.
|
