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Industrial Monitoring and Protection > Unit 3-5 > Flashcards

Unit 3-5 Flashcards

1
Q

What is waste water treatment

A

The removal of undesirable components to improve quality to release into the environment via physical, chemical or biological processes

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2
Q

Objectives of biological treatment

A

Reduce BOD and Convert majority of organic compounds into stable biomass, which can be settled as sludge.

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3
Q

Two biological treatment systems

A

Lagoon and activated sludge

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4
Q

Lagoons are categorized as ____________-growth systems

A

Suspended

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5
Q

What are three broad levels/stages of wwt

A
  1. Primary/preliminary
  2. Secondary
  3. Tertiary
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6
Q

Goals of primary treatment

A

To remove large materials and corse solids to enhance subsequent treatments

Remove course and settleable solids
Equalize WW flow
Neutralize flow

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7
Q

What are comminutors and when are they used?

A

After course screens where fine screens aren’t used.

Grinds up remaining solids

Dried, baled and sent to landfill
Or sent to next stage

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8
Q

What level would you find a grit chamber?

A

Preliminary

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9
Q

Neutralization is a commonly used in municipal waste water treatment plants

A

Yes?

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10
Q

Grit chamber sludge vs sludge at the bottom of 1• clarifier

A

Removal of Inorganic solids vs organic solids

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11
Q

What is the purpose of 2• biological treatment?

A

Removal of suspended solids, mainly organics, no removed by preliminary treatment

Remove dissolved biodegradable organics
Nitrogen and phosphorus

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12
Q

Aerobic vs anaerobic

A

Bacteria consume organic pollutants as food

Organics+O2 –> CO2+H2O+energy+biomass

Absence of O2
Organics -> CO2+CH4/acid+energy
Very slow and sensitive

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13
Q

Where is anaerobic digestion used?

A

Sludge digesters

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14
Q

Factors affecting bacteria digestion rate/processes

A

Food/nutrients (N P K S Ca Mg)

Temperature

Oxygen

PH

Presence of toxins

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15
Q

Why is the addition of O2 required (WWT)

A

To promote aerobic processes.
2mg/L

Ratio of nitrogen and phosphorus

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16
Q

What is activated sludge

A

Settled sludge that contains living or active microbes that are retuned to the reactor (increasing available biomass and speed)

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17
Q

What is mixed liquor

A

Combination of microbes and waste water in the reactor

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18
Q

RAS

A

Return Activated Sludge

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19
Q

WAS

A

Waste activated sludge

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20
Q

What is the importance of pulp and paper industry in Canada

A

One of Canada’s largest and most profitable industries.

Employs 41,000 Canadian

Major export

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21
Q

Source material for pulping

A

90% softwood & hardwood
Fibers->Cellulose

Recycled materials (paper/cardboard)

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22
Q

Soft vs hardwood fibers

A 
Soft
Spruce/fir
Long fibers
High quality strength 
Bags and boxes
Hard
Aspen, birch
Short fibers
Lower strength 
Printing paper (smooth and evenness)
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23
Q

Main components of wood?

A
  1. Cellulose and hemicellulose organic fibers (used for pulp)
  2. Lignin (hold fibers together)
  3. Extractants (removed and recovered- ie fatty acids and turpentine)
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24
Q

What is pulp

A

Pulp is the raw material used for paper. It is made of cellulose/fibers of wood.

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25
Q

What is pulping

A

Process of extracting fibers cellulose from wood or other raw material to make pulp

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26
Q

What are the two types ofpulping?

A

Mechanical and chemical

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27
Q

Which pulping process yields the most?

A

Mechanical

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28
Q

Which pulping process makes higher quality paper?

A

Chemical

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29
Q

4 types of mechanical pulping

A

SGW

PGW

RMP

TMP

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30
Q

Chemi-mechanical pulping types (2)

A

CTMP

BCTMP

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31
Q

What is the name for chemical pulping

A

Kraft

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32
Q

SGW

A

Stone Groundwood

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33
Q

PGW

A

Pressure Groundwood

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34
Q

RMP

A

Refinery Mechanical Pulp

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35
Q

TMP

A

Thermal Mechanical Pulping

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36
Q

CTMP

A

Chemi-thermo-Mechanical pulping

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37
Q

BCTMP

A

Bleached chemi-thermal Mechanical pulping

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38
Q

General processes/steps of pulping in order

A
  1. Debarking
  2. Wood chipping
  3. Defibration/delignification
    1. 1 liquor recovery
  4. Bleaching
  5. To paper plant or market
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39
Q

2 types of debarkers

A

Drum- logs tumble and roll in a large drum

Ring- fed and stripped through teeth on rotating heads

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40
Q

defibration vs delignification

A

removal of ligni from wood by mechanical (force and pressure), heat or chemical processes to release wood fibers

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41
Q

what is stone ground pulp

A

logs are pushed against a grindstone. teases fibers out. Lignin is retained.

High yield, bad quality

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42
Q

SGW vs PGW

A

Wood is ground in grindstone vs pressurized grinder

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43
Q

what is a refiner (pulp)

A

woodchips go into a large refiner

  • large round metal disks
  • spin opposite directions
  • teeth

medium yield and quality

44
Q

What is the raw material for thermo-mechanical pulp? What is the quality of paper produced

A

chips or fines exposed to high-pressure steam

yield high, quality better than other mechanical

45
Q

Explain BCTMP process

A 
woodchips, 
washed/steamed/drained, 
chemicals to soften and remove lignin
refiners,
pulp washed, screened and then bleached
46
Q

What method of pulping is mostly used in canada

A

Kraft

47
Q

Explain Kraft pulp process

A

Woodchips

High temp and chemicals (acidic sulfite and kraft- alkaline) break down chemical bonds of lignin.

sulfite added to enhance bleaching

liquor cycle

48
Q

Explain Liquor recovery process (long answer test)

A

White->black->green->white

  1. White (NaOH) is added to wood chips
  2. Lignin dissolves into liquor and turns it black
  3. black liquor is evaporated
  4. Black liquor is then burnt to remove bonded lignin-> generates heat and electricity
  5. smelt (inorganics) is recovered from boiler and water is added. Green liquor (Na2CO3)
  6. causticize with Ca(OH) to return back to the white liquor
49
Q

difference between white and black liquor

A

Lignin

50
Q

Which yield more pulp, kraft or refiner mechanical?

A

mechanical

51
Q

Give an example of energy recovery in liquor recovery cycle

A

When lignin is burnt out of black liquor to produce smelt. The heat from burning off the bonded lignin is used to make heat, steam, turn turbine and create electricity

52
Q

Name three oxidant agents used in the bleaching process

A

Elemental Cl2
Chlorine dioxide (ClO2)
Oxygen (O2)
Ozone (O3)

53
Q

what is the conventional method of bleaching? What is the concern?

A

Elemental Cl2

produces large amount of dioxins
- Toxic, cancerous, bioaccumulates

54
Q

What are the purposes of mechanical and chemical bleaching?

A

mechanical- Remove chromorphores (pigments) not lignins

Chemical- remove all lignins

55
Q

Difference between integrated and market pulp

A

Integrated (paper factory is with pulp factory)

Market pulp, pulp is packaged and sold to paper producer as raw material

56
Q

4 components of a paper machine

A
  1. Wet end (forms slurry, vibrated and gravity into a mat)
  2. Pressing (removes water)
  3. Drying (steam heated cylinders)
  4. Calender (presses to desired thickness and unifrom)
  5. sheets cut into desired sizes and baled/stacked/shipped
57
Q

Energy use of pulp and paper (vs others)

A

Energy-intensive 30% of Canada’s industrial energy use

3rd largest industrial polluter

58
Q

What has been done to alleviate energy use in the pulp sector

A

Switching to renewable biomass for fuel/energy

increases in energy efficiency

59
Q

How can pulping sludge be reused?

A

Very good fertilizer (biomass, N, P, wood fiber and water)

Crop yield increase and increases soil quality (ie. water retention)

60
Q

Name environmental issues regarding pulp and paper

A 
Energy-intensive
water intensive
water pollution (n, p, solids, chemicals and temp)
bleaching (toxic by-products)
sludge and toxic waste
air emmissons
deforestation
smell
Ink (heavy metals)
Paper is thrown out
61
Q

There is always a textbook solution available for treatment of any raw water, as water treatment techniques are well
developed. (T/F)

A

No. Only generalized designs using a combination of several processes

62
Q

Pre-sedimentation is an effective way to remove H₂S from untreated water. (T/F)

A

False. Pre-chorination step

63
Q

What is meant by “water stabilization”?

A

pH adjustments

Many processes are pH dependant (ie. coagulation)

64
Q

Name three main treatment processes of water treatment.

A

Coagulation, Flocculation, Sedimentation, Filtration, Disinfection

65
Q

Why suspended particles don’t settle down? What are the key processes to remove suspended particles?

A

Most have an electrostatic negative charge. Prevent from colliding and repel each other

Coagulation and Flocculation

Overcome charges and bring particles together to form larger particle (flocs) that settle faster

66
Q

What is a coagulant? Which one is not a coagulant?

a. Alum or aluminum sulphate, AL₂(SO₄)₃
b. Sodium hydroxide (NaOH)
c. Ferric chloride, FeCL₃

A

A and C are cogulants

67
Q

Turbulent flow is desirable during flocculation. (T/F).

A

False. Gentle mixing

68
Q

Name three aesthetics factors of source waters.

A

Taste, color, ordor

69
Q

Sedimentation basin (clarifier) is always right after a coagulator. (T/F)

A

False- flocculator

70
Q

What are the fundamental differences between conventional and alternative sedimentation basins?

A

Space they need. Alternative make larger floccs that settle faster so the basin can be shorter

71
Q

Why v-notch weirs are usually used in different basins of a water treatment plant?

A

Launders: outlet structure that takes water from the very top that all floccs have settled out of

72
Q 
Where is turbulence desirable?
A. clarifier 
B. flocculator 
C. coagulator 
D. storage reservoir
A

C. Uniform distribution of coagulants

73
Q

Name two types of conventional circular basin.

A

center feed and periferal feed

74
Q

Why the bottom of many clarifiers is sloped?

A

settles sludge is swept by a scraper to the center into a collection chamber

75
Q

When a DAF system is used?

A

When particles do not settle out easily (air diffuser, bubbles, fine floc attach to bubbles, skimmed of top, water collected lower in tank

76
Q

What is the main purpose of filtration?

A

removing remaining suspended solids by passing through a porus medium
clays, silts, micobes, ions, flocs

77
Q

Pre-sedimentation is an effective way to remove H₂S from untreated water. (T/F)

A

False. Pre-chlorination step

78
Q

Concentration of pathogens and suspended particles in groundwater sources are often insignificant, yet many treatment plants include a filtration process for better treatment. Why?

A

Avoid the risk of something happening, like the walkerton tradgedy. It is a back up incase something goes wrong in the process or with the source

79
Q

The pore size of a rapid sand filter should be smaller than the size of suspended particles. (T/F)

A

False. Larger. Stuck in pores or adhere to sand

80
Q

When is a backwash cycle triggered?

A
  1. a predetermined level of head loss
  2. increase in filter effluent turbidity
  3. at a pre-set interval
81
Q

What are the functions of the under drain in a filter?

A
  1. covers the floor of the filter box
  2. support the filter media
  3. collect and convey filtered water
  4. distribute backwashed water and air
82
Q

Direct filtration is the common system for rivers with variable turbidity. (T/F)

A

F. best waters with low and steady turbidity (lakes)
(coag-floc-filtration)

rivers are best in a conventional system (coag-floc-sedimentation-filtration)

Inline (ground and upland surface)
(coag, filtration)

83
Q

Explain the purpose and steps of the jar test in detail.

A

To determine the optimal dosage of coagulants and optimal chemical conditions

  1. Test color, turbidity, pH, and alkalinity of raw water
  2. addition of coagulant (does differ) to 6 samples
  3. mixing high to low
  4. water settles for an hour
  5. measure again and look for the sample with optimal does
84
Q

Sedimentation basin (clarifier) is always right after a coagulator. (T/F)

A

False- flocculator

85
Q

What are the fundamental differences between conventional and alternative sedimentation basins?

A

Space they need. Alternative make larger flocs that settle faster so the basin can be shorter

86
Q

Why v-notch weirs are usually used in different basins of a water treatment plant?

A

Launders: outlet structure that takes water from the very top that all flocs have settled out of

87
Q

two factors for effectiveness of disinfection

A

contact time and concentration

88
Q

Name two types of conventional circular basin.

A

center feed and perifferal feed

89
Q

Name two advantage and two disadvantages of chlorination.

A

Residual- protects water for a long time
cheap, quick, reliable and easy to use

  • reacts with organics creating THM’s and HAA’s
  • Potential health risk
  • does not work on protoza
90
Q

THMs and HAAs are by-products of ozonation. (T/F)

A

False. Chlorine

91
Q

What is the main purpose of filtration?

A

removing remaining suspended solids by passing through a porus medium
clays, silts, microbes, ions, flocs

92
Q

Ozonation is a very strong chemical disinfectant. (T/F)

A

True. Strongest. O3. Extra bond. toxic to most microorganisms

93
Q

Concentration of pathogens and suspended particles in groundwater sources are often insignificant, yet many treatment plants include a filtration process for better treatment. Why?

A

Avoid the risk of something happening, like the walkerton tragedy. It is a back up incase something goes wrong in the process or with the source

94
Q

Why do you think the use of UV technology for disinfection is on the rise?

A

reduced risk of toxic by-products,
People dont like the idea of ingesting Cl2
chemical free

95
Q

Which disinfection technique is most common? Most effective? Most time-efficient?

A

Chlorine
Ozone (but no residual)
UV (no contact time)

96
Q

When is water softening required in Prairie Provinces? Why?

A

when water sources are hard (high in Ca and Mg deposits) dolomite areas

97
Q

Hardness should be removed from water as it has negative health impacts. (T/F)

A

False. Removed to increase lifespan of plumbing and machinery

build up, soaps and taste

98
Q

Define water disinfection

A

The removal, deactivation or killing of pathogenic micro-organisms (bacteria, virus, protozoan)
found in all raw water

99
Q

Groundwater sources often contain optimal level of fluoride. (T/F).

A

True. Added to surface water

100
Q

What is the composition of sludges?

A 
Mineral solids (clay/silt/sand)
chemicals from treatment process
101
Q

Which source of water results in production of more sludge: surface or groundwater?

A

Surface- more TSS

102
Q

Explain the general processes of sludge treatment.

A

Thickened (concentrated), Dewatered, Dried, baled, reused (fertilizer) or landfilled

103
Q

What are the advantages of sludge thickening?

A

Reduces volume (reduces storage needs, transportation, disposal, processing)

104
Q

How sludge can be reused?

A

fertilzer for cropland or golf courses
alum recovery
cement or bricks

105
Q

Energy conservation and efficiency is very important in water and wastewater treatment plants, because this industry is energy-intensive. (T/F)

A

True

Increasing demands and regulations

106
Q

Why do you think the use of UV technology for disinfection is on the rise?

A

reduced risk of toxic by-products,
People don’t like the idea of ingesting Cl2
chemical free

107
Q

How sludge can be reused?

A

fertilizer for cropland or golf courses
alum recovery
cement or bricks

Industrial Monitoring and Protection (5 decks)

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