Lecture 3

Question 1

How much time each element spends in a liquid
reservoir, such as a river stream, lake or ocean, is
called the?

Answer 1

Residence Time

Question 2

Residence Time

Answer 2

How much time each element spends in a liquid

reservoir, such as a river stream, lake or ocean,

Question 3

Point Source Pollution

Answer 3

comes from a specific source, like a pipe factories, industry,

can be monitored and controlled by a permit system

Question 4

nonpoint source

Answer 4

pollution associated with stormwater or runoff

cannot be traced to a direct discharge point such as a wastewater treatment facility

Question 5

Examples of NP

Answer 5

oil & grease from cars

fertilizers

animal waste

grass clippings

septic systems
sewage & cleaners from
boats

household cleaning products

Question 6

Pollutant Transport

Mechanisms

Answer 6

NPS pollutants build up on land surfaces during dry
weather

Atmospheric deposition
Fertilizer applications
Animal waste
Automotive exhaust/fluid leaks

Question 7

Pollutants from Agriculture

Answer 7

Sediment

Nutrients

Pathogens

Pesticides

Question 8

Sediment رواسب

Answer 8

Reduces light penetration

Clogs gills of fish and aquatic animals.

Question 9

ِِِNutrients

Answer 9

Act as fertilizer for algae & aquatic plants which can cause highly varying dissolved oxygen levels.

At low DO levels, the aquatic life has the potential to be harmed.

Question 10

Toxics

Answer 10

Can impact life and contaminate drinking water supplies.

Question 11

Bacteria/Pathogens

Answer 11

Are an indicator of possible viruses present in the system.

Question 12

Water Pollution sollution

Answer 12

Fertilize garden and yard plants with manure or compost
instead of commercial inorganic fertilizer.

• Minimize your use of pesticides.
• Do not apply fertilizer or pesticides near a body of water.
• Grow or buy organic foods.

• Do not drink bottled water unless tests show that your tap
water is not contaminated. Merely refill and reuse plastic
bottles with tap water.

• Compost your food wastes.
• Do not use water fresheners in toilets.
• Do not flush unwanted medicines down the toilet.

• Do not pour pesticides, paints, solvents, oil, antifreeze, or other
products containing harmful chemicals down the drain or onto
the ground.

Question 13

Controlling Water

Pollution

Answer 13

Upstream:

before the problem occurs

Downstream:

After the problem occurs

Question 14

Upstream Methods of

Controlling Water Pollution

Answer 14

Process modification in industry:
Elimination of pollutants and toxics

Avoidance of direct discharge into:
water bodies
storm sewers
sanitary sewers

Identification of storm drains

legislation and regulation: guidelines and
laws establishing limits on discharge

Question 15

Downstream Methods of
Managing Sewage: Small scale

Temporary /short term:

Answer 15

packing it out
pit privies
single-use holes
trench latrines

Question 16

Downstream Methods of
Managing Sewage: Small scale

Long-term

Answer 16

settling ponds

septic tanks

septic fields

Question 17

Downstream Methods of

Sewage Treatment: Large Scale

Answer 17

domestic sewage treatment:

preliminary: screening and removal of large
contaminants

primary: straining and settling of solids

secondary: removal of biodegradable organic
matter and nutrients

tertiary: removal of residual dissolved
nutrients

Question 18

Downstream Methods of

Sewage Treatment

Answer 18

mechanical: filtering, gravity separation

chemical:
flocculation, coagulation

biological:
microbes or macrophytes

aerobic or anaerobic

disinfection: chlorination, ozonation, etc.

(pathogen control)
‘physical plant’/ ‘engineered’ approach
(usually centralized, large scale)

‘constructed wetland’ approach (centralized or
decentralized, large or small scale)

Question 19

Many naturally occurring elements, minerals and chemicals are naturally cycled through the environment (it is similar to the hydrologic cycle)

Answer 19

Geochemical Cycles

Question 20

Geochemical Cycle

Answer 20

Elements, minerals and chemicals naturally cycled by the environment