Principal Water Pollutants

March 16, 2011

Standards

• W-5: SWBAT describe the process of wastewater treatment

• W-6: SWBAT list and describe the major types of water pollution

Wastewater

• Def: Water that contains waste from home and industry

Goal of Wastewater Treatment

• Water is filtered and treated to make the water clean enough to return to a river or lake

What’s in the Wastewater?

• Most of the wastewater from homes contain biodegradable material that can be broken down by living organisms

• Water from the kitchen and toilet contain plant and animal wasters, paper, and soaps all of which are biodegradable

Biodegradable Waste

Biodegradable or Not?

• Banana Peel

• Soda Can

• Slaughterhouse waste

• Manure

• Glass

• A polyester shirt

The Womp Womp Factor

• Wastewater treatment plants may not remove all the harmful substances in water

• Ex: Household water that contains toxic substances

Sewage Sludge• A byproduct of wastewater

treatment

• The solid material that remains after treatment

$$$• Sludge that contains a high

concentration of toxic chemicals must be disposed of as hazardous waste

• The sludge is often incinerated, and then the ash is buried in a secure landfill

Sustainable Sludge• If the toxicity of the sludge can be

reduced to safe levels, sludge can be:

• 1) Turned into fertilizer

• 2) Combined with clay to make bricks for buildings

Wastewater Treatment Process

• 1) Filtration

• 2) 1st Settling Tank

• 3) Aeration Tank

• 4) 2nd Settling Tank

• 5) Chlorination

Fats, Oils, and Grease (F.O.G’s)

• Builds up in the sewer system and can cause back ups

• Do’s:

• Recycle used cooking oil

• Put food scraps in trash

• Don’t:

• Pour F.O.G.s down the drain

• Use the toilet as a trash can

• Use rags or cloths towels to clean grease

#2 Artificial Eutrophication

• Eutrophication caused by humans

Eutrophication• def: A natural process where a

body of water receives excess nutrients, which causes a loss of oxygen.

• Some nutrients are GOOD, but too many may cause a body of water to become eutrophic

Causes of Eutrophication

• Fertilizers from farms, lawns, and gardens

• Phosphates in some detergents

Whiteboards

• On your whiteboards, write down the definition of thermal pollution and provide some major causes of such.

#3: Thermal Pollution• def: the degradation of water

quality by changing the temperature of a natural body of water

Sources of Thermal Pollution

• Power plants and other industries use water in their cooling systems and then discharge the warm water into a lake or river

• CFU

It’s getting hot in herre...

• As the water temperature rises, the amount of dissolved oxygen decreases

#4: Groundwater Pollution

• Pollutants usually enter groundwater when polluted surface water percolates down from the surface.

Leaking Underground Storage Tanks(LUST)

• Major source of groundwater pollution

• Estimated 1 million+ in the US

• Gas stations

• Storage tanks develop leaks as they age, allowing pollutants to enter the ground

Problems with LUST

• The location of an aging UST is not always known, so tanks cannot be replaced or repaired until they have leaked enough pollutants.

Love Canal, NY

Other Sources of Groundwater Pollution

• Septic Tanks

• Unlined landfills

It’s all connected!

Whiteboards-PPM• Water contamination is often

measured in parts per million (ppm).

• If the concentration of a pollutant is 5 ppm, there are 5 parts of the pollutant in 1 million parts of water.

• Q: If the concentration of gasoline is 3 ppm in 650,000 L of water, how many liters of gasoline are there in the water?

ppm Solution

• If there are 10 ppm of arsenic in 500,000L of water, how many liters of arsenic are there?

Clean-up Time

• Groundwater pollution is one of the most challenging environmental problem the world faces.

• The process for some aquifers to recycle water and purge contaminants can take 100s or 1000s of years

Sticky Icky Icky

• Pollution can cling to the materials that make up an aquifer.

• Putting clean water in a dirty aquifer is useless!

Ocean Pollution

• At least 85% of ocean pollution comes from activities on land

Oil Spills• Each year, approximately 37

million gallons of oil from tanker accidents are spilled into the oceans

Caution: Slippery when...Oily?

• Oil spills only account for 5% of oil pollution in the oceans.

• Most of the oil that enters the oceans come from cities and towns.

• 200-300 million gallons/yr

Quick Check

• How can limiting nonpoint sources of oil pollution help keep the oceans clean?

Biomagnification

• def: the build up of pollutants at higher levels of the food chain