Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Environmental health > Water Treatment Technologies > Flashcards

Water Treatment Technologies Flashcards

1
Q

First law of ecology

A

everything is conected to everything else

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

can’t be removed through filtering

A

dissolved inorganic matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

examples of dissolved inorganic matter

A

® Minerals leaching into groundwater leading to hardness, alkalinity, and other mineral contents
® Fertilizer runoff, mostly phosphates, nitrate, and sulfates
® Industrial discharges of all kinds, especially from metal finishing trade
® Salinity (principally chlorides) from sea water or saline ground water intrusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

® Natural impurities from decay of vegetable and animal matter
® Domestic waste, general biological debris and decay products, soap, detergents
® Industrial discharges (e.g. food processing and intensive agriculture, tanning, papermaking, and organic chemical
industry)- fats, oils, and solvent
® Residues of pesticides

A

Dissolved organic matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

examples of suspended impurities

A

• Colloids (organic and inorganic: clay, and iron or manganese oxides)
• Suspended Inorganic
• Suspended Organic
(Plant and animal particles; Industrial and domestic products)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

sources of colloids

A

® Industrial wastes from e.g. china clay or paper processing

® A component of sewage solids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

examples of suspended inorganic impurities

A

sand, Industrial materials from coal washings, mining wastes, lime
and other sludge, oxide dust, fly ash, flue washings, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

living matters impurities

A

• Microorganisms
® Algae, viruses, protozoa, micro-fungi, etc.
® Occurrence is promoted by nutrients and favorable breeding grounds (e.g. domestic sewage)
® Exposure to light promotes algal growth
® E. coli is a common contaminant tested
• Larger life
® Fish, worms,crustaceans, insect larvae, etc.
® Occur naturally and may breed in large numbers where food is plentiful
® Aquatic plants, floating and rooted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

gases which occur in all natural waters

A

o2 and co2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

underground sources contain this gas

A

high co2, h2s (from volcano)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

can result from biological decay from industrial discharge

A

NH3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

gas which is often dosed deliberately

A

Cl2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

algal growth effect on gas

A

removes co2 and raise 02 to supersat in daytime

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

T or F: water treatment method would depend on nature of impurities

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T or F: dissolved impurities and living matter can be removed by filtration

A

false, only suspended matter can be removed

microorganisms: must disinfect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

commonly involved in removal of suspended solids and color and also in bacteria removal

A

sedimentation
coagulation
filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Passing the water through a layer of sand or other material that retains the suspended solids

A

Filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

limitations of filtration

A
  • Capacity of the sand to remove impurities is compromised

- Backwashing (reversing the flow) is recommended so that the filter would not clog

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Permitting water to remain quiescent in large settling basin so
that the suspended solids may settle to the bottom

A

Sedimentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T or F: Sedimentation can remove dissolved matter and suspended matter that are too small

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

involves coagulants ie aluminum sulfate –most used and effective

A

coagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

mechanism of coagulants

A

(Coagulants: certain chemicals applied to the water wc produce an insoluble gelatinous and flocculent precipitate and precipitate absorbs and entraps the suspended solids in the water and thus hastens their sedimentation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

bacteria removal vs solid

A

bacteria need final disinfection (with chlorine or other acceptable agents to ensure destruction of bacteria that may cause disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how many minutes should bacteria be hoild?

A

3-5 minutes starting from time bubbles form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

method of removal or Neutralization of Tastes, Odors, Objectionable
Minerals, and Dissolved Gases

A

aeration, treatment with certain chemicals

copper sulfate to control algae) and activated carbon (carbon absorbs toxins, remedy water with odor and taste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

exposing water in thin films or droplets to the o2 of atmosphere to volatize or vaporize organic conaminants

A

aeration (to remove volatile compounds esp pesticides wc cannot be removed by filtration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How to remove hardness or softening

A

ion exchange

membrane filtration such as reverse osmosis or nanofiltration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Common treatment processes for surface water source

A

aeration (air stripping)

disinfection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

a waterfall aeration process wherein raw water trickles over a medium within a cylinder to mix water and air

A

packed tower aeration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

used to control spread of communicable water diseases; kills pathogenic microorganisms found in drinking water

A

disinfection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

effects of disinfecting agent in water supply

A
  • bacterial: capacity to destroy pathogenic microoganisms in a given treatment process
  • residue/remnant: ability to disinfect water that is re-contaminated in the
    distribution system due to seepage of pathogens into the pipes
32
Q

Things to consider in residue/remnant effect

A
  • Handling is an important consideration on how water can
    be contaminated again.
  • a property that is unique to chlorination (Residual chlorine is important in order to address the contamination that is acquired as the water passes from the source to its final destination since pipes that carry
    water can also contaminate it)
33
Q

Factors affecting effectiveness of disinfection

A
  • Contact duration between disinfecting agent and pathogens
  • Nature and concentration
  • Dosage and strength of disinfecting agent
  • Characteristics or condition of water during disinfection
34
Q

Conditions for effective disinfection:

A
  • Low Suspended Solids (1 mg/L)
    § Suspended solids may prevent the action of disinfecting agents with the pathogens
  • Low Organic Matter and Other Oxidizable Subs
    § May react with disinfectants and reduce the effect the
    disinfecting agents have on the pathogens
35
Q

most widely used disinfectant for water supplies

A

chlorination (min contact time: 30 minutes; residual must be 3-5 ppm)

36
Q

treatment method with residue effect

A

chlorination

37
Q

When is the best time to put chlorine in drinking water?

A

afte three processes

38
Q

Properties of chlorination

A
  • Poisonous, corrosive
  • 2.5 times heavier than air
  • Greenish yellow gas
  • Fatal if inhaled in large quantities
  • Sharp, suffocating
    odor
  • Causes irritation to mucus lining of
    the lungs
39
Q

commercial preparation of chlorine

A
  • Liquid chlorine
  • Gas chlorine
  • High test hypochlorite (HTH), granular (75%)
  • Bleaching agent, NaOCl
    § Cannot be used since it has detergent and not pure chlorine
40
Q

Another method of disinfection which uses a strong oxidizing agent wc is naturally occurring component of fresh air and serves as protective layer produced by the reaction between UV rays of sun and earth’s upper atmosphere

A

ozonization

41
Q

T or F: ozone is a very reactive and unstable gas with a short half-life before it reverts back to oxygen

A

true

*Most powerful and rapid acting oxidizer talo niya cl (all bacteria, mold, yeast spores, organic material,
and viruses)

42
Q

Ozone is usally used on

A 
® Microflocculation 
® Viral inactivation
® Turbidity reduction 
® Bacterial disinfectant
® Taste, odor, and color
removal
® Iron and manganese
oxidation
® Organics removal
43
Q

Ozone concentrations for inactivation

A
  • 0.5 - 0.6 mg/L: 99.9% enteric viruses
  • 1.1 mg/L: 99.99% Cryptosporidium oocysts
  • 0.5 mg/L: G. lamblia
44
Q

uses corona discharge principle

A

ozone genration

45
Q

Explain corona discharge principle

SEE DIAGRAM PUTA

A
  • Dry air or oxygen is passed between high-voltage electrode and ground electrode separated by a dielectric material
  • In excess of 80% of the applied energy is converted to heat
    that, if not rapidly removed, caused the ozone to decompose
46
Q

method of disinfection which uses oxidizing and germ-killing effect through UV lamp

A

UV Radiation

*most natural purification and disinfection principle

47
Q

How does UV radiation inactivate pathogens

A

destroy DNA thus preventing replication

48
Q

Most sensitive to UV radiation are viruses and bacteria in vegetative forms such as:

A
  • Salmonella typhosa
  • Mycobacterium tuberculosis
  • Vibrio cholerae
  • Hepatitis virus
  • Shigella dysenteriae
    (higher doses: g lamblia cysts and cryptosporidium oocysts)
49
Q

T or F: spores need higher doses of UV to be destroyed

A

true

50
Q

germicidal lamp that converts electrical power into UV-C

A

UV Generators

51
Q

Membrane Filtration Processes

A

• Feed (Solution which enters the system and is pressurized)
• Permeate (Solution (usually purified water) which passes through the
membrane and is collected for use)
• Concentrate (brine, retentate- Solution, which exists from the system, that has not passed
through the membrane; Enriched in particular rejected material)

52
Q

• Applications of Membrane Filtration

A
  • Suitable for removal of particulates from pre-treated water in
    the range of 0.1-100 micrometers
    § Provided that the total suspended solids do not exceed 100 ppm
53
Q

one of the most important membrane process; a pressure drive process that retains virtually all ions and passes water

A

reverse osmosis

*effectively removes most organics, bacterial and particulate matter and also inorganic contaminants with rates of 60-99%

54
Q

Pressure applied in reverse osmosis must exceed what?

A

osmotic pressure of salt solution against semipermeable membrane leaving salts behind, only pure water can pass through the other side

55
Q

final product of reverse osmosis

A

purified water, beneficial minerals can be removed

56
Q

process that uses semi-permeable membranes to separate macromolecules in solution; applied to municipal systems and removes organic contaminants

A

ultrafiltration

57
Q

important factors in retention in ultrafiltration

A

size of solute

molecular shape of solute

58
Q

Ultrafiltration vs reverse osmosis

A

membranes have looser pore structure than reverse osmosis

59
Q

• Membrane properties involved in ultrafiltration

A

• Available in cellulose, acetate, polysulfone, acrylic, noncellulosic polymers
• Have been prepared from polymers such as: polycarbonate,
polyvinyl chloride, plolyamides, polyvinyl fluoride

60
Q

Applications of ultrafiltration system

A
  • Municipal water treatment plants (both surface and groundwater supplies)
  • Removal of total organic carbon, trihalomethane and color
  • NF membranes exhibit as high as 40% rejection of salts (May react with disinfectants and reduce the effect the disinfecting agents have on the pathogens)
61
Q

nanofiltration involves water softening using what

A

low-pressure reverse osmosis membranes

62
Q

nanofiltration softening and organics removal is usually done on

A

low total dissolved solids and slightly brackish water

63
Q

molecular weight cut off membranes for nanofiltration

A

<200-500 as opposed to tight RO membranes

64
Q

other characteristics of nanofiltration

A

• Rejects hardness
• Repels bacteria and virus
• Removes organic-related color without generating undesirable
chemical compounds (e.g. chlorinated hydrocarbons)

65
Q

Distillation process

A

® Water is heated to boiling point then changed to gas, leaving
non-volatile impurities
® Water is cooled then changed once more to water that is now free from dissolved and dissolved matter
® Distillation process may retain 0.3% to 0.5% of water impurities after treatment
® Bacteria may re-colonize on the cooling coils during inactive
periods

66
Q

Impurities removed by distillation

A
  • Almost all impurities from water (99.5% of impurities)
  • Microorganisms
  • Dissolved solids
  • Nitrate
  • Most organic compounds
  • Sodium
  • Heavy metals
  • Hardness
  • Radionuclides
67
Q

T or F: any form of volatile organic contaminants and certain pesticides can be rmoved by distillation

A

false

68
Q

uses of distillation

see treated water quality

A
  • Small scale application in laboratories
  • Preparation of purified water in pharmacy for injection
  • Production of potable water from sea and brackish water
69
Q

water softening uses

A

ion exchange process (one type of ion contained in water is absorbed into an insoluble solid material and replaced by an equivalent quantity of another ion in the same charge)

70
Q

resin used in ion exchange process has what

A

sodium ion (when hard water passes, it exchanges with calcium and magnesium ions; used again for regeneration)

71
Q

• Uses of ion exchange process:

A
  • For upgrading municipal or private water in industry
  • Water softening
  • Purification of boiler needs
72
Q

Why must hard water be softened?

A
  • Interferes with all types of cleaning tasks
  • Dishes and glassware washed with hard water may be spotted when dry
  • Causes films on glass shower doors, walls, and bath tubs
  • Hair washed in hard water may feel sticky and look dull
  • Scale build up in hot water heater
  • Scale deposits corrode and clog plumbing
73
Q

Impurities Removed by Activated Carbon (AC) Filters

A 
• Organic chemicals that cause taste, odor, color problems,
mutagenicity, toxicity
• Chlorine and chlorination by-products
• Inorganic such as arsenic, chromium, mercury
• Pesticides and solvents
• Polychlorinated biphenyls
• Polycyclic aromatic hydrocarbons
• Radon
• Toxic contaminants
74
Q

Impurities Not Removed by Activated Carbon (AC) Filters

A 
• Microbes
• Sodium
• Nitrates
• Fluoride
• Hardness
• Lead and other heavy metals are removed only by specific types
of AC filter
75
Q

(See exposure time and effect on bacteria)

A

(See exposure time and effect on bacteria)

Environmental health (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions