Water Pollution

1. Water Pollution

2. Do you want to drink this water? Name some pollutants that you see in this water. Name some pollutants that you might not be able to see in this water. Have you seen places like this?

3. PotableWater Clean, fresh, drinking water Water fit for human consumption

4. Water Pollution • Any physical or chemical change in water that adversely affects the health of humans or other organisms • both natural sources & human activities • 2 types of pollution source: • Point source pollution • Nonpoint source pollution

5. Point Source Pollution • Pollutants discharged from a specific location • “direct discharge into water” • Ex) Pipes, sewers, ditches easily identified with source of pollution • Easily identified & traced • Today, less than 15% of pollution

6. Nonpoint Source Pollution • Also called polluted runoff • Pollutants enter bodies of water over large areas • “indirect discharge into water” • Ex) contaminated runoff- precipitation picks up & carries away pollutants a • difficult to trace because of multiple sources

7. Point vs. Nonpoint Point NonPoint • Oil Spills caused by Shipwrecks, oil drilling, etc. • Sewer treatment plant overflows • 72% of water pollution attributed to agricultural runoff • Fertilizer runoff • Animal wastes • Pesicides • Soil erosion • Municipal Water Pollution- • Urban runoff (untreated garbage, oil, grease)

8. 8 Types of Water Pollutants • Sewage • Infectious Agents/Pathogens • Sediment • Plant Nutrients • Inorganic chemicals • Organic chemicals • Radioactive substances • Thermal pollution

9. 1. Sewage • release of wastewater and organic waste such as animal manure, plant debris, and detergents. • Sources: Sewage, dishwashers, animal feedlots, paper mills, & food processing facilities. • Harmful effects: • decomposing bacteria degrade water quality by depleting dissolved oxygen • causes fish & other forms of oxygen-consuming aquatic life to die. • Can cause disease • Tijuana, Mexico- pollution caused by dumping raw sewage into rivers & coastal waters has forced beaches in San Diego Calif to close • outbreaks of cholera and dysentery have occured

10. 2. Infectious Agents/Pathogens • Infectious organisms that cause diseases enter water systems through raw sewage or animal wastes • Viruses, parasites, bacteria • Typhoid, cholera, dysentery, schistosomiasis, malaria, polio, infectious hepatitis • 1993 Cryptospridium contaminated water supply in Milwualkee • 370,000 people with diarrhea, several people with weakened immune systems died

11. 3. Sediment • Excessive sediment suspended in water • Soil and silt • Sources: Land Erosion- agriculture, construction, mining, logging, etc. • Harmful effects:1) cloud water & reduce photosynthesis 2)carry pesticides, bacteria & other harmful substances, 3) settle out & destroy feeding and spawning grounds of fish (reefs and shellfish beds) 5) clog & fill lakes, artificial reservoirs, stream channels & harbors.

12. 4. Plant Nutrients • Chemicals used to stimulate plant growth • Water soluble & contain nitrate, phosphate and ammonium ions.’ • Sources: Sewage, manure, and runoff of agricultural and urban fertilizers. • Harmful effects: • Cause excessive growth of algae & other aquatic plants, which die, decay, deplete water of dissolved oxygen and kill fish. • Eutrophication- process in which lakes receive nutreitns causeing increase in plant growth and photosynthesis Oligotrophic Eutrophic

13. To much Nutrient: The Dead Zone in The Gulf of Mexico • “The Dead Zone in the Gulf of Mexico”- Mississippi River deposits nutrient pollutants into Gulf • Area of Gulf a “dead zone” because of algae blooms dying off and decomposers depleting the dissolved oxygen • Shrimp and fish avoid it but slower sea stars, crabs, and clams die from lack of oxygen

14. 5. Organic Chemicals • Contain carbon • Oil, gasoline, plastics, pesticides, cleaning solvents, detergents, hormones • Sources: Industry, household cleansers, surface runoff from farms & yards. • Harmful effects: • threaten human health by causing nervous system damage (some pesticides), reproductive disorders (some solvents) and some cancers (gas, oil, solvents). • harm fish and wildlife. • Plastics- littering waterways, killing fish, birds, and aquatic organisms • Oil Spills- • 1991 Persian Gulf War • 1989 Exxon Valdez

15. 6. Inorganic Chemicals • Elements & compounds that lack carbon • Water soluble, acids, lead, mercury, heavy metals, arsenic, chromium • Do not break down easily & remain in water for long time • Sources: seepage and surface runoff, (Point and nonpoint) industrial discharge, mines, and household cleansers. • Harmful effects:1) make fresh water unusable for drinking or irrigation 2) Poisonous- cause liver, kidney and brain damage 3) harm fish and other aquatic life • Ex) Mercury and Minamata, Japan Mother bathing her fetal-poisoned 16 year old daughter physically crippled since birth due to environmental industrial mercury poisoning in the local Minamata, Japan, water supply.

16. 7. Radioactive Substances • Radioactive isotopes that emit radiation Ex) iodine, radon, uranium, cesium & thorium • Sources:Nuclear & coal-burning power plants, mining and processing of uranium and other ores, nuclear weapons production, natural sources.Harmful effects:Genetic mutations, miscarriages, birth defects, and certain cancers. • Ex) 1973- Richland, Washington radioactive waste leaked into soil • 21,000 people exposed when it made its way into Columbus River • 1950’s SRS discharged radioactive waste into Savannah River • Dept of Energy still studying possible health effects

17. 8. Thermal Pollution • Excessive heat or temperatures • Sources: • Water cooling of electric power plants & some types of industrial plants. • Almost half of all water withdrawn in United States is for cooling electric power plants. • Harmful effects: • Lowers dissolved oxygen levels & makes aquatic organisms more vulnerable to disease, parasites, and toxic chemicals. • power plant first opens or shuts down for repair, fish & other organisms adapted to a temperature range can be killed by the abrupt change in water temperature- known as thermal shock. http://www.absorblearning.com/media/attachment.action?quick=v4&att=2230

18. Water Management and Treatment

19. Water Management: Increasing the Supply of Freshwater • Competition for water resources exist between private companies, states, and countries • Dams and reservoirs built to store more freshwater for large populations • Aqueducts and canals help divert it from plentiful areas to areas in need • Wells increase the use of groundwater • Colorado River- Dams, Reservoirs and Aqueducts manage its water

20. Water Management Issues • Controversies and expense are main drawbacks to management • Water rights disputes between states and countries • Groundwater- withdraw more than can be replenished naturally • Also increased risk of pollutants- toxic chemicals, sediment, pathogens, and nutrients • Dams and reservoirs increase population of pathogens • Disrupt natural flow of surface water systems • Ecosystems can be destroyed • Affects migration of fish (dams and transport of water)

21. Water Management Examples: Hoover Dam and Colorado River • Benefits • Lake Mead provides water to many areas in the region • Hydroelectric power • Controlled flooding of Colorado River • Drawbacks • Disruption of ecosystems and aquatic organisms • Silt carried by Colorado River to Gulf of California no longer travels downstream • part of reason Colorado River dries up before it reaches Gulf • Political Issues- • Water Rights and Water allocation between states- Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. On November 24, 1922, these states signed the Colorado River Compact

22. Three Gorge Dam, China • Benefits • flood control • 10% of China’s energy needs • navigation of large barges • water directed to water-starved north • Drawbacks • soil erosion deposits of silt at the dam • Increase in pathogens • Endangered species threatened • Issues • a million people displaced communities without compensation • possible contamination by toxic pollutants

23. Invasive Species- Drawback of Water Management non-indigenous species (e.g. plants or animals) that adversely affect the habitats they invade economically, environmentally or ecologically • introduced into waterways via canals and aqueducts, water management strategies that help cause the spread of invasive species • Ballast Water

24. Water Management- Desalination: Increasing the Supply • Salty groundwater or ocean water made fit to drink • Expensive because it requires a large energy output • Used in North Africa and Mid East • Saudi Arabia- 27 plants produce 70% of water supply • Problems- what to do with left over salt • Returned to source increases salinity and could harm ecosystems

25. Desalination Methods:Distillation • Distillation- salts are removed by heating and boiling water • One of the oldest methods for obtaining freshwater from saltwater • Also eliminates most natural and unnatural contaminants • Process occurs in nature- evaporation & condensation • Water evaporates and salt crystals are left behind • Cooled water is fresh and potable • Expensive process-requires a lot of heat to evaporate the water & coolant to condense water

26. Desalination Methods:Reverse Osmosis & Freezing • Reverse Osmosis- salt water forced through a strainer (membrane with tiny pores • Less expensive process, used in many coastal regions • Water sometimes has a taste • Freezing- freezing salt water separates salt as a brine slush • Ice is fresh water • Occurs naturally (icebergs) • Requires energy artifically

27. Which method of desalination would you use and why? • You are a small country located beside a large, salty sea in an arid region. While short on freshwater resources you have ample access to oil reserves. • You are a large, island country located near the Artic Circle. Ice covers the majority of your land and your harbors are often frozen over with ice. You also have access to plenty of geothermal energy from the dormant volcanoes that helped form your island several centuries ago. • You are a small, coastal city and because of an increase in population and construction of new homes and shopping centers your aquifer is becoming stressed. Salt-water is intruding into the aquifer.

28. Water Treatment • The process of of cleaning water to make it safe for people to drink (potable) or for any other uses • Raw Water Treatment • Wastewater Treatment • Treatment is performed so that it meets desired water quality criteria for its fitness for the intended use. • physical, chemical and biological characteristics of water are tested • Water quality standards vary significantly due to different environmental conditions, ecosystems, and intended human uses • temperature, pH, dissolved oxygen, conductivity, nitrogen, ammonia, dissolved metals, microorganisms (pathogens)

29. Raw Water Treatment • Raw Water- Water obtained from natural sources such as streams, reservoirs, and wells. • always contains impurities • Treatment performed to: • Increase water resources • Treat contaminated or dirty water

30. Raw Water Treatment • In U.S, municipal water- treated to remove impurities • Safety checks monitor quality to ensure it is safe to drink • In Mexico, China, & parts of Africa- tap water not considered safe to drink • A large supply of potable, freshwater is essential to national development • Why?

31. Reasons to Treat Raw Water • Industrial wastewater discharged into the river • Farm chemicals often flow into rivers as non-point pollution • Any chemicals or pathogens entering the river (not removed by wastewater treatment) must be removed

32. Steps of Raw Water Treatment process • Source- The Savannah River is the primary source for Columbia County, Richmond County, and most of North Augusta • Intake- Water taken from the source. • Screening- large objects and debris are screened out of water as it is drawn into treatment plant. • Pretreatment- Addition of Alum and chlorine • Alum- added for coagulation • Chlorine added for disinfection • Coagulation and Flocculation- • Coagulation- particles in water stick Alum • Flocculation- particles stick together

33. Steps of Raw Water Treatment • Sedimentation- Water and flocculation flow into a sedimentation basin • Floc settles to the bottom & is removed from water • Filtration- water flows through filters of sand & gravel to remove any remaining particles • Final Chemicals added • Chlorine as a disinfectant • Fluoride to help prevent tooth decay • Phosphate and other corrosion control chemicals • Storage- allows time for chlorine to mix with water & provides space for storage before public use

34. Steps of Raw Water Treatment

35. Raw Water Treatment and Water Quality • Sampling and Analysis- performed to make sure processes are working and water is safe before it leaves the plant • Federal and State governments set standards for drinking water • Safe Drinking Water Act- main federal law that ensures the quality of Americans' drinking water. • passed by Congress in 1974 to protect public health by regulating the nation's public drinking water supply. • actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and ground water wells. (SDWA does not regulate private wells which serve fewer than 25 individuals.) Source: http://www.epa.gov/safewater/sdwa/

36. Raw Water Treatment: Water Quality Tests • Turbidity- cloudiness of water caused by suspended material (soil, etc) • Measure by passing a beam of light through the water & seeing how much light is reflected off the particles. • Hardness- caused by dissolved minerals (Calcium & Magnesium) in water. Makes it difficult to lather soap • Hard water can damage equipment & shorten life of fabrics

37. Raw Water Treatment: Water Quality Tests • pH Adjustment for Corrosion Control- goal is to reduce amount of lead & copper leaching into water from pipes • Low pH water (< 5) is acidic & can cause pipe corrosion • Phosphate- adding phosphate decreases solubility of lead in drinking water

38. Municipal Sewage Treatment / Wastewater Treatment • Wastewater- spent or used water with dissolved or suspended solids, discharged from homes, commercial establishments, farms, and industries. • used in washing, flushing, manufacturing, etc.; sewage. • Why treat wastewater? • Wastewater (sewage, ) usually undergoes several treatments at a sewage treatment plant to prevent environmental and public health problems. • Treated wastewater is then discharged into rivers, lakes, and oceans

39. Treatment Steps • Primary Treatment • Secondary Treatment • Tertiary Treatment

40. Primary Treatment • Removes suspended and floating particles (sand, silt, paper trash, sticks, etc.) through mechanical processes • 1st- passes through a metal grate/screen to pull out paper trash and sticks • 2nd – brief residence in a grit tank that allows sand and gravel to settle out. • Solids settled out are identified as Primary Sludge • Does little to remove organic and inorganic compounds • Wastewater treatment facilities for about 11% of population have only primary treatment

41. Secondary Treatment • Biological degradation of remaining suspended solids using microorganisms (aerobic bacteria to decompose them • 2 forms of this process • 1) Trickling filters- aerated rock beds • 2) Aeration tanks- activated sludge made up of bacteria decompose remaining solids

42. Secondary Treatment • Water is removed from top and secondary sludge- particles and microorganisms that settle out is removed from the bottom • Secondary sludge can be landfilled or can be spread on the land as fertilizer • Water undergoing primary and secondary treatment is free of organic wastes such as sewage • 62% of wastewater treatment plants in the U.S use both Primary and Secondary Treatment • most water is chlorinated & released into surface water

43. Tertiary Treatment • Last phase removes carbon-based compounds (organics) and some inorganic compounds (heavy metals, nitrates, and phosphate) • Nitrate and phosphate are nutrient pollutants • Heavy metals are inorganic pollutants • Advanced wastewater treatment methods that include a variety of biological, chemical and physical processes • Tertiary treatment often used to purify wastewater in communities where water is scarce

44. Tertiary Treatment • 27% of U.S population has wastewater treatment facilities using tertiary treatment • Example- use of artificial and natural wetlands for both secondary & tertiary • Secondary- Sewage is piped in to holding ponds where solids settle out and are decomposed by bacteria and fungi • Tertiary-Than effluent flows through marshes (wetlands) where it is filtered & cleansed by aquatic plants (duckweed, water hyacinth, • etc.) • Richmond County employs constructed wetlands at Phinizy Swamp

46. Disposal of Sludge 5 possible methods 1) Anaerobic bacteria digests sludge in large digesters (containers) and kept warm (about 35 C) break down organic materials into gases (methane and CO2) • Methane can be trapped and burned to heat the digesters • Sludge used as fertilizers 2) could be used directly as a fertilizer3)

47. 3) Incinerated- dried sludge can be burned (may contribute to air pollution) & heat can be used to generate electricity 4) Ocean dumping- some countries dump sludge into the ocean directly Ocean Dumping Ban Act- barred ocean dumping of sludge and industrial waste in 1988 5) disposal in sanitary landfill- space costs money

49. Septic Tanks • Many private residences in rural areas use as sewage disposal method • How does it work? • Household sewage is piped to septic tank • Particles settle to the bottom • Grease & oils are at the top where bacteria decomposes much of it

50. How does it work? • Wastewater containing suspended organic and inorganic material flows into the drain field through network of perforated pipes set in gravel or crushed stone trenches • Located just below surface, bacteria decompose remaining material • Purified wastewater percolates into groundwater or evaporates from soil