CEE 370 Lecture #1 9/9/2015

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David Reckhow CEE 370 L#1 1

CEE 370Environmental Engineering

Principles

Lecture #1Introduction I

Reading: Chapter 1 in Mihelcic & Zimmerman

Updated: 9 September 2015 Print version

Introduction to Environmental Engineering

CEE-370Lecture 1

Presented by: Rassil and Julie

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Introduction to CEE 370

Syllabus

Environmental Engineering

The application of science and engineering principles: To care for and/or restore our natural environment

To solve environmental problems associated with human activities

Impacts everyone and everything Plants

Insects

Animals

Humans

Ecosystems

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The Big Picture Human overpopulation (~7,363,183,400)

Resource use (land, water, fossil fuels, crops, meat…)

Intensive farming Higher meat production and crop farming

Increased irrigation

Nutrient pollution

Land use Desertification

Habitat change

Land pollution

Hydrology Distribution of water resources

Quality of water resources

Challenges:• Fresh water supply• Running out of oil• Climate change• Mounting of solid

waste

Main Umbrellas - Air

Air pollution

Acid rain

Greenhouse gases

CO

Particulate matter

O3 at the ground level

Pb

Nitrogen oxides

Sulfur oxides

Indoor air quality

CO

Radon

Mold and moisture

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Main Umbrellas - Land

Land/soil quality Heave metals: Pb

Insecticides

Pesticides

Fertilizers

Petrols, oils, solvents etc..

Ash

Main Umbrellas – Drinking Water

Water quality Surface water

Ground water Microorganisms (Fecal and total coliform, Legionella, Giardia

lamblia, cryptosporidium, viruses, turbidity)

Disinfection by-products (Haloacetic acids, trihalomethanes, bromate, chlorite, others)

Inorganic chemicals and metals (As, Pb, F, Chromium, nitrates, nitrites, Cd, Asbestos…)

Organic chemicals (dioxin, PCBs, toluene, vinyl chloride… )

Radionuclides (radium, uranium…)

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Cycling of Mercury

(http://www.mfe.govt.nz/publications/waste/mercury-inventory-new-zealand-2008/2-mercury-environment)

Common Environmental Engineering Terms

Pollution prevention At source rather than at end-of-pipe

Sustainable engineering

Water/wastewater treatment technology

Environmental remediation Contaminant removal from environmental media

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Some Basic Rules

mass(g)=MW (g/mol) x n (Moles) Example: What is the number of moles of KCl (MW=74.45

g/mol) in 74.45 g of KCl?

n=mass/MW=0.07445/74.45= 0.001 mol

Molar concentration: Ci (mol/L)=ni (mol) / Volume (L) In 1 L of water: Ci=0.001/1=0.001 mol/L

Mass concentration: Ci (g/L)=massi (g) / Volume (L) In 1 L of water: Ci=0.001 g/L

Some Basic Rules

Dilution: C1V1=C2V2

Example: You have a 12.0 M solution of hydrochloric acid (HCl) and your experiment requires 150.0 mL of 8.0 M HCl. How much water and how much 12.0 M HCl should you use to make 150.0 mL of 8.0 M HCl?

How much HCl?

12V1= 8*150

V1= 8*150/12= 100 mL of HCl

How much water?

150-100=50 mL of water

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Mass Balance

Conservation of mass to account for “material” entering and leaving a system to analyze physical systems

1. Define you control volume

2. Choose the material of interest

3. Consider all possible sources (inputs) and sinks (exports)

Typical mass balance

Evaporation Precipitation

Sediment BottomAlgae

Surface water

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Basic Questions

What is the “stuff ”? Identify the species of interest

How much “stuff ” is there? Concentration Concentration: the “amount” of a substance per “amount” of

media Common forms (assuming constant pressure):

Mass balances of substance A in air:

CA=MassA / VolumeAir

Chemical reactions of substance A in air:

[A]=MolesA / VolumeAir

Basic Questions

How fast is the “stuff ” entering and exiting a specified volume? Flow rate or Q Flow rate: the volume of fluid that passes through a given

media per unit time

Q (L3/T)= Volume / time = Area * velocity

If we have 10 gallons of tap water in 10 minutes:

Q=10 gal/10 min=1 gal/min

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Typical mass balance

Example: N

Accumulation= Σimports – Σexports + Σsources – Σsinks

=ΣCinQin-ΣCoutQout+S-kVC

Evaporation Precipitation

Sediment BottomAlgae

Surface water

Qin

Cin

Qout

Cout

Lab Session #1

Objective: To measure volumetric flow rate (Q) and mean velocity (v) of a small stream

Three methods: Floating markers

Tracer-dilution

Mechanical current meters

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Floating Markers Method

A measure of the time it takes for an object to float a specified distance downstream, or a measure surface velocity (vsurface)

Eq. 1,2

Eq. 3

Eq. 4

Tracer-Dilution Method(Instantaneous)

A measure of the downstream concentration of a tracer (known volume and concentration) discharged/injected instantaneously (sudden/slug) upstream over time until the concentration reaches the background level.

Calculating the discharge from the slug injection method involves integration, or calculating the area under the curve of concentration vs. time

Tra

cer

conc

entr

atio

n (C

)

Time (t)

Area

Cb

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Mechanical Current Meters Method

Swoffer meter: Based on stream velocity at a specific point (depth and width) for a specified time frame (in seconds).

0.6D 0.2D

0.8D

Lab Session #1

Today: Make groups of 4. Read and understand the lab session handout for next week’s lab exercise for

all three methods.

Day of: Expect to step into the stream (knee-depth at most) so wear appropriate

clothing (flip-flops, shorts). Bring a notebook to record your data and take notes. Leave on time to reach Groff Park by 2:25 PM If you don’t know the directions and/or need a ride, talk to your TA.

Write-up Prepare a write up (1 per group) as per technical report handout and the lab

handout (last couple of pages) Turn in your write-up at the beginning of the following lab session. You have a two-week period instead of the traditional one-week period.

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Next To next lecture

Reading for next class:

M&Z: Chapter 1 Hardin’s “Tragedy of the Commons” Science, 13 Dec

1968 (pg 1243)

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