Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

waste water > Lesson Seven > Flashcards

Lesson Seven Flashcards

(55 cards)

Start Studying
1
Q

Conventional Surface Water Treatment Process Steps

A

Intake and screen,
Low lift pumping,
Rapid mix and coagulation,
Flocculation,
Clarification/sedimentation,
Filtration,
High lift pumping into the distribution system

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

direct filtration

A

Similar to conventional filtration but without the clarification step.
Generally limited to raw water with turbidity less than 20 NTU and color less than 40 TCU.

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

Intakes - Purpose

A

To draw water from lakes, reservoirs, or rivers.

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

Single-Level Intakes - Advantages

A

Usually less complicated.
Less costly to construct and operate than multi-level structures.

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

Single-Level Intakes - Disadvantages

A

Water entering during spring, summer, and fall can be of poor quality due to lake stratification.
Issues can arise in deeper, more complex lake environments.

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

Multi-Level Intakes - Advantages

A

Multi-Level Intakes - Advantages

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

Multi-Level Intakes - disadvantages

A

Generally more complex and expensive to construct and operate than single-level intakes.

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

Intake Gates - Purpose

A

To control the flow of water into the intake structure.

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

Common Types of Intake Gates/Valves

A

Slide gates (steel or cast iron),
Gate valves,
Butterfly valves

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

Screens - Purpose

A

To remove large debris from raw water (e.g., logs, fish, algae).

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

Bar Screens - Purpose and Cleaning

A

Screen out large debris.
Cleaned either mechanically or manually.

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

Wire Mesh Screens - Material and Cleaning

A

Usually made of corrosion-resistant material (e.g., stainless steel).
Rotating “travelling screens” use a water jet to discharge debris.

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

Microstrainers - Purpose

A

Primarily to remove algae and other aquatic organisms.

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

Coagulation and Flocculation - Objective

A

To develop a chemical precipitate (floc) to enable the removal of suspended matter, especially non-settleable solids (turbidity, algae, color).

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

Coagulation - Definition

A

Rapid dispersion of coagulant in water to destabilize particles so they can agglomerate and form precipitates.

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

Coagulation Mechanisms

A

Charge neutralization
Sweep flocculation

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

Rapid Mixing (Flash Mix) - Purpose

A

To rapidly and thoroughly mix the coagulant chemical throughout the water.

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

Flocculation - Definition

A

Gentle agitation of water to promote contact between particles to form larger floc.

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

Factors Affecting Coagulation/Flocculation Effectiveness

A

Raw water quality (turbidity, color, alkalinity, pH, temperature).
Dosage/type of coagulant and coagulant aid.
Degree of coagulant dispersion (rapid mixing).
Intensity of mixing during flocculation

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

Clarification - Purpose

A

To remove suspended solids to reduce the particulate load on filters and extend filter run times.

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

Sedimentation - Definition

A

Clarification accomplished by decreasing the velocity of the water being treated so that settleable suspended material will sink by gravity.

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

Zones of a Sedimentation Basin

A

Inlet Zone
Settling Zone
Sludge Zone
Outlet Zone

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

Inclined Plates or Tube Settlers - Purpose

Study These Flashcards
A

To increase settling efficiency in sedimentation basins by providing a high ratio of effective settling surface area per unit volume.

24
Q

Solids-Contact Units - Definition

Study These Flashcards
A

Units that combine coagulation, flocculation, and sedimentation in a single unit.

25
and Ballasted Flocculation/Settling
Microsand is added to the water along with coagulation chemicals to accelerate the process.
26
Dissolved Air Flotation (DAF)
Pressurized water is injected, forming small gas bubbles that attach to solids and float them to the surface.
27
Filtration - Purpose
To remove particles and floc from the water that is not removed during clarification.
28
Rapid Gravity Filtration - Mechanism
Water level or pressure (head) above the media forces water through the filter media. Impurities are captured.
29
Common Filter Media
Sand Anthracite (coal) Granular activated carbon (GAC) Garnet Gravel (as supporting layers)
30
Backwashing - Purpose
To clean filters by pushing clean water backwards through the filter, loosening and carrying away trapped particles.
31
Filter Run - Definition
Length of time a filter is in service between backwashes.
32
Parameters for Determining Backwash Need
Head loss Increase in turbidity/particle counts (breakthrough) Filter run time (specific period elapsed)
33
Pressure Filtration - Key Difference from Gravity
Filter is completely enclosed in a pressure vessel and operated under pressure.
34
Diatomaceous Earth Filtration - Mechanism
Filter media (diatomaceous earth) is added as a slurry and collects on a septum. Water passes through this coating.
35
Slow Sand Filtration - Mechanism
Water goes through the filter media by gravity at much lower rates. Particles removed by straining, adsorption, and biological action.
36
Cartridge Filters - Material and Effectiveness
Typically made of spun cellulose. Most effective for water with low levels of turbidity and microbiological contamination.
37
Bag Filters - Mechanism
Similar to cartridge filters (physical screening process). Pore size determines particle removal
38
Membrane Filtration - Mechanism
Pressure or vacuum-driven physical separation process where particulate matter is rejected by an engineered permeable membrane.
39
Types of Membrane Filtration (Largest to Smallest Pore Size)
Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis
40
Aeration - Purpose
Stripping/removing volatile organic compounds or undesirable gases H2s methane). Oxidation of inorganic substances (iron, manganese) and selected organics (taste/odor compounds).
41
Fluoridation - Purpose
The process of adding fluoride to water to promote dental health.
42
Chemicals Used in Fluoridation
Sodium Fluoride, Hydrofluosilicic Acid, Sodium Silicofluoride
43
Taste and Odour Control - Importance
Most common type of consumer complaint. Addressing at the source and through plant maintenance is most effective and least expensive.
44
Common Causes of Taste and Odour in Surface Water
Biological growth (algae). Environmental conditions (eutrophication). Urban runoff. Agricultural wastes. Chlorine. Household plumbing.
45
Common Causes of Taste and Odour in Groundwater
Bacterial action. Presence of iron and manganese. High total dissolved solids. Human activities (chemical dumping, landfills).
46
Taste and Odour Control Methods at a Plant Level
Improved coagulation/flocculation/sedimentation. Aeration. Chemical Oxidation. Activated Carbon Adsorption.
47
Chemical Oxidants Used for Taste and Odour Control
Potassium permanganate, Ozone, Chlorine dioxide, Chlorine
48
Activated Carbon Adsorption - Mechanism
Non-specific action over a broad range of taste and odour causing organic compounds. Can be Powdered Activated Carbon (PAC) added to water or Granular Activated Carbon (GAC) in a stationary bed.
49
Iron and Manganese Control - Reasons
Staining of laundry and plumbing fixtures. Red, brown, or blackish water. Taste and odour problems (related to iron bacteria).
50
Techniques for Iron and Manganese Control
Oxidation and filtration. Sequestering. Ion exchange.
51
Oxidation and Filtration for Fe & Mn - Oxidizing Agents
Aeration (for low iron concentration). Chlorine (readily oxidizes iron, slowly manganese). Potassium permanganate (faster manganese oxidation)
52
Sequestering for Fe & Mn - Mechanism
Chemical binding to keep metals in solution (using polyphosphates with chlorine or sodium silicate with chlorine).
53
Ion Exchange for Fe & Mn - Conditions
Effective if iron and manganese are present in a soluble form (e.g., well water without oxygen).
54
Filter Ripening - What is it?
The initial period after backwashing where filter effluent turbidity may be higher until a layer of floc forms on the media.
55
Air Stripping - What does it do?
A type of aeration that passes water over a medium while air flows through to remove volatile compounds.

waste water (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions