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CE 380. Environmental Science and Engineering. Assignment. Write on a piece of paper your name and your answer to the following question: What do environmental engineers do ?. Environmental Engineering (Section 1.1). In general:

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Ce 380

CE 380

Environmental Science and Engineering


Assignment
Assignment

Write on a piece of paper your name and your answer to the following question:

What do environmental engineers do?


Environmental engineering section 1 1
Environmental Engineering(Section 1.1)

In general:

The application of scientific and engineering principles to minimize the adverse effects of human activity on the environment and to safeguard human health and welfare


Assignment1
Assignment

Write on the same piece of paper your answer to the following question:

Why do you need to know this stuff?


Course organization

Air

Noise Pollution

Solid Waste

Hazardous and Radioactive Waste

Water

Wastewater

Course Organization

Sustainability


Sustainability

Sustainability

Primary Chapter: 1

Supplemental Chapter: 17



Assignment due fri
Assignment – Due Fri.

Answer the following questions.

  • What is sustainability?

  • How does it pertain to civil engineering?

  • What are the potential pros and cons of integrating sustainability into projects/policies?


Water part 1

Water, Part 1

Primary Chapter: 10

Supplemental Chapters: 3, 9


Water quantity sources

Section 10.1

Water Quantity & Sources


Water on earth

Total Water Supply

Fresh Water Supply

Available Fresh Water Supply

Salt Water Supply

Water on Earth


Potable water sources
Potable Water Sources

Deep Wells

Springs

Shallow Wells

Intakes

Fresh and Saline



U s water withdrawals in 2005
U.S. Water Withdrawalsin 2005


Water quality

Sections 9.1 – 9.2

Water Quality


Exercise
Exercise

Water, water everywhere but which drop can you drink?

  • Would you drink this?

  • What about it makes it seem okay or not?


Review laws and regulations
Review: Laws and Regulations


The process
The Process

Public concern and/or a recognition of link between cause and effect

Law

Regulations



Drinking water legislation

Section 9.3

Drinking Water Legislation


Activity 1
Activity - 1

Where can promulgated (final) federal laws and regulations be found?

  • Federal Register

  • Code of Federal Regulations

  • Washington Times


Activity 2
Activity - 2

What is the primary law regulating drinking water treatment?

  • Safe Drinking Water Act

  • Clean Water Act

  • Resource Conservation and Recovery Act


Activity 3
Activity - 3

What are the differences between primary and secondary standards?

  • Enforceability

  • Purpose

  • Size of plant covered



Drinking water treatment

Section 10.2

Drinking Water treatment


Drinking water treatment1
Drinking Water Treatment

  • Primary goal: Prevention of disease

  • Secondary goals:

    • Good taste, odor, and color

    • Low hardness

    • Meet irrigation and fire protection needs


Process for potws
Processfor POTWs


Intake
Intake

Surge Tank

Horizontal Centrifugal Pump

Screw


General water treatment
General Water Treatment

Conventional

Vs.

Advanced


Softening

Section 10.2.1

Softening


Why?

Why do we soften water?



What?

What is hardness?


How?

How do we soften water?


Units

= ?

±

Units

How do we get to from mg/L of ions to mg/L as CaCO3?


Example
Example

Find total hardness (in mg/L as CaCO3) of water containing:

Ca2+ = 80 mg/L, Mg2+ = 30 mg/L,

Pb2+ = 160 mg/L, Fe 3+ = 50 mg/L

Na+ = 72 mg/L, K+ = 6 mg/L

Cl- = 100 mg/L, SO42- = 201 mg/L,

HCO3- = 165 mg/L

pH = 7.5


Units section 3 1 2
Units (Section 3.1.2)

ppm vs. mg/L

1 ppm is equivalent to 1 minute in:

a) 1 day

b) 2 years

c) 6 weeks


Approximations and sig figs section 3 2
Approximations and Sig Figs(Section 3.2)

Consider:

  • Problem 3.26 (p. 108)

  • Problem 3.27 (p. 108)

  • Problem 3.29 (p. 108)


Reminder hints for quantitative problems
Reminder Hints for Quantitative Problems

  • Write down the general equation.

  • Write down your units throughout! And use them to come up with your final units.

  • Be reasonable with sig figs.

  • Ignore irrelevant data.

  • If your answer doesn’t make sense, check. If your check gives you the same answer, state why it doesn’t make sense.


More on total hardness
More on Total Hardness

TH = CH + NCH


Calculating alkalinity

CO2

CO2(aq) + H2O H++HCO3-

H++OH-

H++CO32-

+

Ca2+

Limestone

(CaCO3)

Calculating Alkalinity



Example1
Example

Find carbonate and noncarbonate hardness of water containing:

Ca2+ = 80 ppm, Mg2+ = 30 ppm,

Pb2+ = 160 mg/L, Fe 3+ = 50 mg/L

Na+ = 72 ppm, K+ = 6 ppm

Cl- = 100 ppm, SO42- = 201 ppm,

HCO3- = 165 ppm

pH = 7.5


Reminder
Reminder

  • Calculate TH and ALK.

  • Determine CH.

  • Calculate NCH.


Example2
Example

Find the speciation of the hardness of water containing:

Ca2+ = 80 mg/L, Mg2+ = 30 mg/L,

HCO3- = 165 mg/L

pH = 7.5


Reminder1
Reminder

  • Calculate

    • CCH.

    • CNCH

    • MCH

    • MNCH

  • Check your calculations!


Lime soda softening

Sedimentation

Sludge

Lime-Soda Softening

Lime and/or Soda Ash

Hard Water

Mixing

Flocculation

CO2

Sedimentation

Soft Water

Recarbonation

Sludge


Lime soda softening1
Lime-Soda Softening

CO2:

CO2 + 1 Ca(OH)2  1 CaCO3  + H20

CCH:

Ca(HCO3)2 + 1 Ca(OH)22 CaCO3+ 2 H2O

CNCH:

CaSO4 + 1Na2CO3 1 CaCO3  + Na2SO4

MCH:

Mg(HCO3)2 + 1 Ca(OH)21 CaCO3 + MgCO3 + 2 H2O

MgCO3 + 1 Ca(OH)2 1Mg(OH)2 + 1CaCO3

MNCH:

MgSO4 + 1Na2CO3 MgCO3 + Na2SO4

MgCO3 + 1 Ca(OH)2 1Mg(OH)2 + 1 CaCO3



If we’re trying to take calcium out of the water, why do we add lime, which is a calcium-based chemical?


Example softening
Example – Softening we add lime, which is a calcium-based chemical?

To solubility limits with 90% quicklime, 90% soda ash

5 MGD flowrate


Example continued
Example continued we add lime, which is a calcium-based chemical?

First: Determine TH


Example continued1

0 we add lime, which is a calcium-based chemical?

3.5

4.3

4.6

meq/L

Na+

Ca2+

Mg2+

CO2

HCO3-

SO42-

Cl-

Example continued

Second: Determine speciation


Example continued2
Example continued we add lime, which is a calcium-based chemical?

Third: Determine chemical amounts (Section 3.1.3)


Assumptions
Assumptions we add lime, which is a calcium-based chemical?

ALWAYS clearly state you are making an assumption and what that assumption is.

Examples: Assume purity = 98%

Assume generation = 4.2 lb/c/d


Example continued3
Example continued we add lime, which is a calcium-based chemical?

Fourth: Determine sludge quantity


Split treatment ls softening
Split Treatment - LS Softening we add lime, which is a calcium-based chemical?

Lime and/or Soda Ash

Plant Influent

Mixing

Flocculation

Hard Water

CO2

Recarbonation

Sedimentation

Soft Water

Soft Water

Sludge

To Rest of Treatment


Selective ca 2 removal
Selective Ca we add lime, which is a calcium-based chemical?2+ Removal

If Mg2+ ≤ 40 mg/L as CaCO3

(maximum Mg hardness)


Examples
Examples we add lime, which is a calcium-based chemical?

Can selective Ca2+ removal be used if all the hardness is Ca2+ and Mg2+?

1. TH = 210 mg/L as CaCO3

Ca2+ = 120 mg/L as CaCO3

2. TH = 180 mg/L as CaCO3

Ca2+ = 138 mg/L as CaCO3


Example continued4
Example Continued we add lime, which is a calcium-based chemical?

TH = 180 mg/L as CaCO3

Ca2+ = 138 mg/L as CaCO3

Mg2 + = 42 mg/L as CaCO3

Calculate the amount of quicklime and soda ash required in meq/L if you (1) remove the Mg2+ and (2) leave the Mg2+ (selective Ca2+ removal). Assume ALK = 105 mg/L as CaCO3 and CO2 = 20 mg/L as CaCO3.


Other benefits of ls softening
Other Benefits of LS Softening we add lime, which is a calcium-based chemical?

  • Removal of other metals, arsenic, & uranium

  • Reduction of solids, turbidity, & TOC

  • Inactivation of bacteria & viral removal

  • Prevention of corrosion

  • Removal of excess fluoride


Ion exchange softening
Ion Exchange Softening we add lime, which is a calcium-based chemical?


Softening1
Softening we add lime, which is a calcium-based chemical?

  • Softening reaction:

    Na2R + Ca(HCO3)2  CaR + 2 Na(HCO3)

  • Regeneration reaction

    CaR + 2 NaCl Na2R + CaCl2


Example3
Example we add lime, which is a calcium-based chemical?

An ion exchange water softener has 0.1 m3 of ion-exchange resin with an exchange capacity of 57 kg/m3. The occupants use 2,000 L of water per day. If the water contains 280.0 mg/L of hardness as CaCO3 and it is desired to soften it to 85 mg/L as CaCO3, how much should be bypassed? What is the time between regeneration cycles?


Mixing
MIXING we add lime, which is a calcium-based chemical?

Section 3.1.2


Mixing1
Mixing we add lime, which is a calcium-based chemical?

Parshall Flume

Rapid Mix Tank

Fine Air Diffusers


Design equation hydraulic retention time section 3 1 4
Design Equation we add lime, which is a calcium-based chemical?: Hydraulic Retention Time (Section 3.1.4)


In class activity
In-Class Activity we add lime, which is a calcium-based chemical?

A 0.5-MGD water treatment plant will use one flash mixer designed for a 1-minute retention time. Determine the diameter of the mixer. Assume the water depth will equal 80% of the diameter.


Solids removal
SOLIDS REMOVAL we add lime, which is a calcium-based chemical?

Sections 10.2.2 and 10.2.3


Coagulation and Flocculation we add lime, which is a calcium-based chemical?

(Section 10.2.2)


Flocculator
Flocculator we add lime, which is a calcium-based chemical?

Vertical Shaft Type

Horizontal Shaft Type

Baffled Flow Type


Solids by size section 9 1 3
Solids by Size we add lime, which is a calcium-based chemical?(Section 9.1.3)


Coagulation flocculation
Coagulation & Flocculation we add lime, which is a calcium-based chemical?

Al -13 Polycation

Fe-12 Polycation


Sedimentation we add lime, which is a calcium-based chemical?

(Section 10.2.3)


Sedimentation
Sedimentation we add lime, which is a calcium-based chemical?

Purpose: Remove solids


Sedimentation another view
Sedimentation: Another View we add lime, which is a calcium-based chemical?


Design equation overflow rate
Design Equation: we add lime, which is a calcium-based chemical?Overflow Rate


In class activity1
In-Class Activity we add lime, which is a calcium-based chemical?

The detention time and overflow rate for a circular settling basin were determined to be 1.5 h and 0.5 gpm/ft2, respectively. The flow rate will be 250,000 gpd. Calculate the dimensions of the basin.


In class activity2
In-Class Activity we add lime, which is a calcium-based chemical?

A 2-MGD water treatment plant will use two rectangular sedimentation basins designed for a 3-hour total detention time. If the basins will be twice as long as wide, what will be their dimensions? What will be the OFR for each basin? Assume the water depth will equal the width.

  • Assume parallel flow.

  • Assume series flow.


Filtration
FILTRATION we add lime, which is a calcium-based chemical?

Section 10.2.4


Filtration we add lime, which is a calcium-based chemical?


Filtration methods
Filtration Methods we add lime, which is a calcium-based chemical?

Gravity Filters

Biflow Filter

Upflow Filter

Pressure Filter


Filtration mechanisms
Filtration Mechanisms we add lime, which is a calcium-based chemical?


Slow vs rapid sand filters
Slow vs. Rapid Sand Filters we add lime, which is a calcium-based chemical?


Typical gravity filter
Typical Gravity Filter we add lime, which is a calcium-based chemical?

Water level during filtering

Water level during backwash

0.5 m

Wash-water trough

Freeboard, 0.6 m

Sand, 0.65 m

Gravel, 0.5 m

Underdrain System


Disinfection
DISINFECTION we add lime, which is a calcium-based chemical?

Sections 9.1.5 and 10.2.5


Disinfection we add lime, which is a calcium-based chemical?


Activity 11
Activity - 1 we add lime, which is a calcium-based chemical?

Why is drinking water disinfected?


Activity 21
Activity - 2 we add lime, which is a calcium-based chemical?

Who linked contaminated water to infectious disease?

Leonard McCoy

John Snow

Marcus Welby


Activity 31
Activity - 3 we add lime, which is a calcium-based chemical?

When was the discovery made?

1600s

1700s

1800s


Activity 4
Activity - 4 we add lime, which is a calcium-based chemical?

In general, what is an indicator organism and why is it used?


Size comparison

10 microns we add lime, which is a calcium-based chemical?

Virus

0.05 - 0.1 m

Bacteria

0.5 - 1.5 m

Red Blood Cell

5 m

Sperm

60 m

Size Comparison


Pathogen removal inactivation
Pathogen Removal/Inactivation we add lime, which is a calcium-based chemical?

Where does this occur in a water treatment plant?


Activity 5
Activity - 5 we add lime, which is a calcium-based chemical?

What are the options for disinfecting water?


Activity 6
Activity - 6 we add lime, which is a calcium-based chemical?

What are characteristics of the ideal disinfectant?


Activity 7
Activity - 7 we add lime, which is a calcium-based chemical?

Adequate disinfection is a balance between which two variables?

Concentration and Time

Concentration and Flow rate

Flow rate and Surface area


Chlorination
Chlorination we add lime, which is a calcium-based chemical?

chlorinator


Chlorine demand or breakpoint chlorination
Chlorine Demand or we add lime, which is a calcium-based chemical?Breakpoint Chlorination

Chloro-organic and chloramine destruction

Chlorine removal by reducing compounds

Formation of free chlorine

Chloro-organic and chloramine formation

Chlorine residual

Free Residual

Breakpoint

Combined Residual

Chlorine added


In class activity3
In-Class Activity we add lime, which is a calcium-based chemical?

  • If 1.5 mg/L of chlorine is being used and the demand is 1.2 mg/L, what is the residual?

  • For the same plant, if 550,000 gpd is being treated and chlorine will be bought in 1-ton containers, how long will one container last?


Ultraviolet light
Ultraviolet Light we add lime, which is a calcium-based chemical?

Hg Vapor

Hg Vapor


Ozonation
Ozonation we add lime, which is a calcium-based chemical?


Storage and distribution
STORAGE AND DISTRIBUTION we add lime, which is a calcium-based chemical?

Section 10.3


Storage and Distribution we add lime, which is a calcium-based chemical?


Sludge management
SLUDGE MANAGEMENT we add lime, which is a calcium-based chemical?


Sludge Management we add lime, which is a calcium-based chemical?


Other treatment options
OTHER TREATMENT OPTIONS we add lime, which is a calcium-based chemical?

Section 10.2.6


Lead we add lime, which is a calcium-based chemical?


Membrane treatment
Membrane Treatment we add lime, which is a calcium-based chemical?


Phoenix proposed wtp
Phoenix Proposed WTP we add lime, which is a calcium-based chemical?


In class activity4
In-Class Activity we add lime, which is a calcium-based chemical?

Why would an industrial plant treat incoming potable water?

Why would a resident treat incoming potable water?


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