Pure Water

Unit Map Set Up

Unit Name: Water Purification and Wastewater treatment

Unit Essential Question: Why is it important to purify and treat water?

Unit Map Set UpLesson essential questions and vocab (as we go)

Lesson Essential QuestionWhy must water be purified?

ObjectivesUnderstand that water is not pure

Understand why water is not pure

“Pure” waterWhat do you think of when you hear this?

Let’s test this.

Pure WaterWater is never pure in nature

Most effective of all natural solvents

Examples: Sugar Water, Coca Cola

Pure WaterWater holds substances in suspension

Fast moving- holds large particles

Slow moving- holds smaller particles

VocabSolution- molecules of one substance dissipated among the molecules of another substance

Suspension- solid particles held temporarily or permanently in a liquid

Solvent- substances that dissolve other substances

Exit Question What did you see in your water?

Water Processing

Warm-upWhat is a solution? Give an example.

Lesson Essential QuestionHow is water processed?

ObjectivesDiscuss how water is processed

Processing WaterTreated depending on where it comes from

Clean groundwater needs little pre treatment

Processing WaterMunicipal reservoir water, upland streams, and lakes with limited inflow need minimal treatment

Processing WaterWater from rivers with industrial agriculture and municipal wastes needs extensive treatment

Treatment Systems2 types in use

Individual Household systemsSeptic treatment systems

Large-scale wastewater treatment systemsVary based on nature and size

ActivityPollution travel map

Exit QuestionWhy is it important to understand what is in our water?

Water Impurities

Warm-upWhat is this?

Lesson Essential QuestionWhat are some chemical water impurities?

ObjectivesOutline impurities that must be removed from water for use by humans.

Water Impurities 3 categoriesChemicalBiologicalturbidity

Chemical Impurities Can result in 1 of 3 conditionsWater that is dangerous to drink

Undesirable color or smellToo acidic or alkaline

Chemical Impurities To be used for human consumption, water pH should be near 7.0

Minerals, metals and salts are almost always present in clear water

Chemical Impurities Distilled water is close to pure, but contains impurities

Low levels of dissolved minerals and metals is healthy for people

Chemical Impurities When concentrations get high, water no longer good and becomes detrimental to human health

Chemical Impurities Water from ground supplies contains dissolved iron or manganese Forms rust when exposed to oxygenToilet bowls, sinks, plumbing fixtures

Chemical Impurities Hard water-result of excess calcium or magnesium, form scale deposits that clog up pipes and plumbing Make soap less effectiveTastes badTreated with “softening” agents

Chemical Impurities Sulfur content in water

Sulfur dioxide- rotten egg smell

Yellows clothes if washed

Chemical Impurities Dissolved nitrogen and phosphorusCommon fertilizers, water-soluble

Promote algae growthCause serious health problems

Chemical Impurities Dissolved hydrocarbonsDisolved methane, methanol, and various alcohols

Tannin- hydrocarbon from decaying organic matter

Excess chlorine- bad tasteExcess fluorine- discolorations on teeth

Chemical Impurities Testing for Pesticide Concentrations Lab

Turn in Questions at the end of class

Vocab Hard water- a result of excess calcium or magnesium

Water Impurities

Warm-up

How is hard water treated?

Lesson Essential QuestionWhat are some biological impurities in water?

ObjectivesOutline impurities that must be removed from water for use by humans.

Biological ImpuritiesRange from mammals to viruses and from aquatic trees to algae

In water treatment, fish, crustaceans, worms, and macro-invertebrate are removed at the beginning by screening

Biological ImpuritiesLarger plants and plant parts are also removed by screening

Small plants, including algae are not completely removed by screening, they require treatment

Biological ImpuritiesAlgae

Tiny green plants that grow in sunlight and air

Generally harmless but can remove oxygen from water that will kill fish

Biological ImpuritiesBacteria and Fungi

Serve as decomposers and help break down organic matter and chemicals into harmless compounds

Biological ImpuritiesBacteria and Fungi

Can be dangerous as pathogens (disease causing organisms)Typhoid fever and cholera

Biological ImpuritiesBacteria and Fungi

Protozoa- single-celled animals that occur naturally in all healthy water supplies

Biological ImpuritiesBacteria and Fungi

Certain protozoa pathogenicDiarrhea and dysentery (inflammation of intestine that causes diarrhea- fatal)

Helmiths- microscopic wormlike organisms that can infest the intestinal tract causing illness.

TurbiditySolid matter suspended in liquid

Naturally solid matter held in suspension

Visible concentration= aesthetically unpleasing

Removal important step for human use

VocabMacroinvertebrate- organisms that do not have a backbone and are visible without a microscope.

Algae- tiny green plants that grow in sunlight and air

VocabProtozoa- single-celled animals that occur naturally in healthy water supplies

Helmiths- microscopic wormlike organisms that can infest the intestinal tract causing illness

Water Treatment

Warm-upHow do we treat wastewater?

Lesson Essential QuestionHow are different types of water treated to be safe for human consumption?

ObjectivesList and describe kinds of wastewater generated

Describe how septic systems are designed and how they work

Discuss how wastewater is treated before it is returned to the water

Water TreatmentObjective- produce potable water supply

Majority of water must be purified before it is safe for human consumption

Well WaterGenerally safe Test periodically for biological or chemical contaminants

May contain undesirable levels of iron, manganese, or sulfur, excess calcium or magnesium

Well WaterTreatment systems from commercial sources to remove metals and minerals

Water softeners availableCommercial iron and sulfur removal systems and activated charcoal filter systems for household use

Municipal Water Treatment PlantsVary depending on size of the community and nature of the water source

influent- water moving into a treatment system

Effluent- water that comes out the other end of the system and is ready for use

Municipal Water Treatment PlantsTypical Plan

Figure 15.5

VocabPotable water- water that is chemically and microbiologically safe and that is otherwise suitable for human consumption

VocabInfluent- water moving into a treatment system

Effluent- water that comes out the other end of the system and is ready for use

VocabCoagulation- physical process of smaller particles clumping together to form larger particles that will later be allowed to settle out of the water

VocabFlocculation- process of stirring together influent with coagulants or other additives that assist in the water purification process

Flocculator – large tank where paddles stir the water to induce clumping

Exit Question

What type of system does your family have? Do you do anything extra to make sure the water that you are drinking is pure?

Water Treatment

Warm-up

List the steps in a municipal water treatment plant.

Lesson Essential QuestionHow is water processed through a municipal water treatment system?

ObjectivesList and describe kinds of wastewater generated

Describe how septic systems are designed and how they work

Discuss how wastewater is treated before it is returned to the water

Municipal Wastewater Treatment3 phases

Primary waste treatment

Secondary waste treatment

Tertiary waste treatment

Primary Waste TreatmentMechanical system that collects the wastewater and removes the items that settle from it

Includes a screening device, grit chamber, settling tank, sludge digester, and drying beds

Primary Waste TreatmentRemoves 2/3 of wastes from water

Grit chamber- wastes ground into finer particles to speed up the decomposition

Primary Waste TreatmentWastes then settle into the sedimentation tank

Wastes removed and placed into sludge digester

Secondary Waste TreatmentBiological processing of sewage

½ of all city plants contain this system

Extension of the primary system

Secondary Waste TreatmentPiped through aeration tank to increase oxygen contentAerobic bacteria increase, increases efficiency of treatment

Water then pumped into sedimentation tank for settling

Remaining water discharged after treated with chlorine

Secondary Waste TreatmentSludge sent through aeration tank to allow decomposition

Removes 90% of organic wastes

Chemical compounds (nitrates, phosphates) remain and require more treatment

Tertiary Waste TreatmentChemical processing of sewage wastewater

Removes nitrates and phosphates

More costly Used only when water is being reused

Tertiary Waste TreatmentAdd lime to remove phosphates

Stripping tower to remove nitrates

VocabStripping tower- vertical tank through which the water moves slowly while the lime and water are in contact, allowing the chemical reaction that removes the excess nitrates.

VocabGrit chamber- wastes ground into finer particles to speed up the decomposition

Water Conservation

Warm-upWhat can we do to conserve water?

Lesson Essential QuestionHow can water be preserved?

Water ConservationShould reserve top quality water for drinkingUse lesser quality for washing cars, flushing toilets, and water our lawns

Water ConservationRecycle ALL water, even sewage water

Federal government placing tighter pollution standards on industrial water supplies=forces them to reuse water over and over.

Test ReviewWorksheet