2 pages within 12 hrs

Topic 1

Water Resources

and

Drinking Water Treatment

Hyderabad, India Ghana, Africa

Learning Objectives

• Understand different sources of water, particularly, the groundwater

(aquifer) system

• Know diseases (dracunculiasis, cholera, E. Coli, arsenicosis, etc.)

related to drinking contaminated water

• Know the drinking water treatment process (coagulation and

flocculation, sedimentation, filtration, and disinfection)

• Know key differences between EPA tap water and FDA bottled water

regulations

Outline

• Sources of Water

• Adverse Health Effects from contaminated water

– Cholera, E Coli O157, Cryptosporidiosis, blue baby syndrome, arsenic

contamination

• The Drinking Water Treatment Process

– Group work

• Sources of Drinking Water

– Groundwater: Artesian vs. spring water

• Bottle vs. Tap Water

– Group work: water tasting

Three Basic Requirements for a Healthy Environment

The THREE most important environmental requirements to promote

healthy people/community?

1. Clean Air

2. Safe and sufficient water

3. Adequate and safe food

Food For Thought – California Drought

• Are we still in a drought?

• Will we run out of the water if we don’t conserve?

• If a person is more than willing to pay, should the government exclude

him/her from conservation efforts? Why or why not?

• After a rain, what happens the rainwater? In other words, where does

it go?

U.S. Drought Monitor – Time series (CA) http://droughtmonitor.unl.edu/

Freshwater systems

Although the water covers 75% of the

Earth’s surface, freshwater is rare

• 97.5% = Saltwater

• 2.5% = Freshwater

– 1.7% = Polar ice caps and

glaciers (unusable)

– 0.77% = Accessible fresh water

• Freshwater = relatively pure water

with few dissolved salts (< 0.1%)

Water Resources

All the Access to Freshwater in the World

Available Freshwater Supplies

• Surface water: All water naturally open to the atmosphere (rivers,

lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.)

• Groundwater: Supply of freshwater found beneath the earth’s surface,

usually in aquifers, which supplies wells and springs

Freshwater and human survival

• 37% of domestic water comes from groundwater sources

– 63% comes from surface water (rivers, lakes, reservoirs)

• Rural people in developing nations get water where they can

– Wells, rivers, lakes, rainwater

• Water in developing nations is often polluted with waste

– 1.1 billion people use polluted water

– 1.6 million (mostly children) die each year

Groundwater

Read “article #1 – What is groundwater?”

Unequal Water Distribution

Many areas with high population density are water-

poor and face serious water shortages

Estimated Water Demand in the U.S., 2010

U.S. Water withdrawals – surface vs. groundwater (2010)

Water Uses

• Proportions of these three types of use vary dramatically among nations

Categories of water use by States (2010)

Domestic Uses of Water in a Southern California Community

• What do you think are the largest categories of residential (domestic)

water use in Southern California?

Pair and Share

• Scenario:

An increasing number of people are moving to the arid southwestern

United States (e.g., CA, Nevada, etc.), even though water supplies are

already being overdrawn. If you were the governor of one of the states

in the is region, what policies would you advocate to address this

situation?

O.C. Water Sources

Colorado River Aqueduct (CRA)

O.C. Water Sources – Groundwater basin

• In Northern and central O.C., including

Fullerton, about 60-75% of water comes

from our local groundwater.

• The rest are imported from Colorado and

Northern California (San Joaquin) rivers.

https://youtu.be/Yv3VEFYkcJA

Read and Discuss – Saltwater Intrusion

• Read “Article #2 – Salt water intrusion”

• Review

– Why does salt water intrusion occur? What is the root of the problem?

• Food for thought

– What are some practical and cost effective ways to prevent the salt water

intrusion?

Groundwater Contamination – Saltwater intrusion

• In many coastal areas,

springs of outflowing

groundwater lie under the

ocean

• High water tables keep

pressure in the aquifer

– Freshwater flows into the

ocean

– Wells near the ocean yield

fresh water

• Lowering the water table

reduces pressure, allowing

salt water to flow into the

aquifer and wells

Water is heavy;

therefore, more

water in the aquifer

means more

pressure to push salt

water out

When water table is

lowered, there is less

water (pressure) to

push out salt water –

results in salt water

intrusion

Seawater Contamination: Southern Cal

Recycled water can increase water supply

• Would you drink waste water that has been

purified to meet the EPA’s drinking water

(tap water) standards?

– “Toilet-to-Tap.” Unfortunately, media coined

this term to depict the process of turning

wastewater into potable water.

• Recycled water can be used to irrigate golf

courses and landscapes. In fact, if done

properly (as is done in Orange County),

the treated water can be cleaner or just as

clean as water bottles.

Group work - Recycled water: what needs to be removed?

• In your group

1. Make a list all of the “things” that need to be removed from wastewater in order

to make it drinkable/potable.

2. Think of processes (physical, chemical, or futuristic) that can remove these

“things” that your group just listed.

http://youtu.be/p-f_F3tE9rA

OCWD – Groundwater Replenishment (GWR) System

• The GWR System purification process begins at the OCSD. The sewer

water is treated by the plant to remove nutrients and contaminants

(clean enough to be released into the ocean)

• Instead of disposing the water, up to half of the treated water is purified

even further by Orange County Water District (OCWD) through

microfiltration, reverse osmosis, and UV with hydrogen peroxide

• The portion of the purified water is used for seawater intrusion barrier

and the rest is pumped to Anaheim pond via 13 mile pipes.

GWR step #1: Microfiltration (MF)

• MF uses straws

with tiny holes in the

sides that are 300

times smaller than a

human hair.

• MF filters out

particles, protozoa,

and bacteria, as

well as any viruses

attached to these

objects

GWR step #2: Reverse Osmosis (RO) Pure

Water

Pure

Water Pure

Water

saline

Water

saline

Water

saline

Water

Reverse osmosis is

another filtration

process that uses

pressure to move

water across a very

fine (nano-size)

membrane.

GWR step #3: UV with Hydrogen Peroxide

• UV with hydrogen peroxide (H2O2) provides an additional safety barrier

that disinfects and destroys trace compounds that may have passed

through RO membranes

To watch a video of OC GWR process, go to - https://youtu.be/V7iX4o5Ul88

Why not desalinate rather than recycle wastewater?

• Desalination process uses large amount of pressure (energy intensive) to push water (in the

saltwater) through a RO membrane.

• Read “Article #3 - HB desalination plant OC Register” and decide whether you would or would not

support future desalination plants in Orange County. Then find someone with an opposite view as

yours and discuss your different perspectives.

Cost of Tap Water (2014)

• One acre foot of water is volume of water in about a football-field size

that is one foot deep. It can serve about two houses (4 members) for a

year.

• Imported water is about $1000 per acre foot

• OCWD (GWRS) water is about $430 per acre foot

– After subsidies, cities that are served by the O.C. groundwater basin will pay

about $350 per acre foot.

• In comparison, Carlsbad has a desalination plant that produces water

that costs about $1500 – $2000 per acre foot of water.