© 2011 Pearson Education, Inc. AP Environmental Science Mr. Grant Lesson 74 Wastewater and Its Treatment.

© 2011 Pearson Education, Inc.

AP Environmental Science

Mr. Grant

Lesson 74

Wastewater and Its Treatment

© 2014 Pearson Education, Inc.

Mastery Check

Name three types of water pollutants and provide an example of each. Explain which classes of water pollutants you think are most important in your home area.

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Objectives:

• Define the terms point-source pollution and non-point-source pollution.

• Assess problems of water quality and propose solutions to address water pollution.

• Explain how we treat drinking water and wastewater.

• TED - Too much of the world lacks access to clean drinking water. Engineer Michael Pritchard did something about it -- inventing the portable Lifesaver filter, which can make the most revolting water drinkable in seconds. An amazing demo from TEDGlobal 2009.

© 2011 Pearson Education, Inc.

Point-Source Pollution:

A source of pollution that involves the discharge of wastes from an identifiable point, such as a smokestack or sewage treatment plant.

Non-Point-Source Pollution:

A source of pollution that cannot always be traced to an exact point of entry.

Define the terms point-source pollution and non-point-source pollution.

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Explain how we treat drinking water and wastewater.

• Municipalities treat drinking water by filtering and disinfection in a multistep process.

• Septic systems are used to treat wastewater in rural areas.

• Wastewater is treated physically, biologically, and chemically in a series of steps at municipal wastewater treatment facilities.

• Artificial wetlands enhance wastewater treatment while restoring habitat for wildlife.

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We treat our drinking water

Technology and government regulation have improved our pollution control Treated drinking water is widespread and successful

in developed nations

Before water reaches the user, it is chemically treated, filtered, and disinfected

The EPA sets standards for over 90 drinking water contaminants Local governments and

private water suppliers must meet these standards

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We treat our wastewater

Wastewater includes water that carries sewage and that from households, manufacturing, stormwater runoff, etc. It is treated before being released into the environment

Septic systems = the most popular method of wastewater disposal in rural areas Underground septic tanks separate solids and oils from

wastewater

The water drains into a drain field, where microbes decompose the pollutants

Solid waste is periodically pumped out and landfilled

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We treat our wastewater

© 2014 Pearson Education, Inc.

We treat our wastewater

In populated areas, sewer systems carry wastewater to treatment locations

Primary treatment = physically removes contaminants in settling tanks (clarifiers)

Secondary treatment = water is stirred and aerated Aerobic bacteria degrade organic pollutants

Water is treated with chlorine (and/or ultraviolet light) to kill pathogens

This water, called effluent, is piped into rivers or oceans

Reclaimed water is used for lawns, irrigation, or industry

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Municipal sewer systems

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A typical wastewater treatment facility

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We treat our wastewater

Sludge = solid material resulting from treatment of wastewater Is decomposed microbially in digesters

Resulting “biosolids” are dried then landfilled, incinerated, or used as fertilizer on cropland

Methane-rich gas created by decomposition can be burned to generate electricity

Six million dry tons of sludge are generated in the United States each year

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Constructed wetlands can aid treatment

Natural wetlands have long filtered and purified water Human-constructed wetlands can do the same thing

After primary treatment at a conventional facility water is pumped into the wetland Microbes decompose the remaining pollutants

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Constructed wetlands can aid treatment

Cleansed water is released into waterways or percolates underground

They are havens for wildlife and for human recreation The United States has over 500 artificially constructed

or restored wetlands

Released effluent has helped rebuild coastal wetlands along the Gulf Coast

© 2011 Pearson Education, Inc.

Artificial wetlands clean wastewater

The U.S. has over 500 artificially constructed or restored wetlands

© 2014 Pearson Education, Inc.

TED Video

With cutting-edge nanotech, Michael Pritchard's Lifesaver water-purification bottle could revolutionize water-delivery systems in disaster-stricken areas around the globe.

"On the outside, it looks like an ordinary sports bottle. On the inside, there's a miracle: an extremely advanced filtration system that makes murky water filled with deadly viruses and bacteria completely clean in just seconds."

Allison Barrie, FoxNews.com

Michael Pritchard's water filter turns filthy water drinkable (9:29)