Chapter 14 Water Pollution

WATER POLLUTION Water pollution causes illness and death in humans and other species and disrupts ecosystems. Chief sources of water pollution: Agricultural activities Industrial facilities Mining BUT growth in population and resource use make it increasingly worse Added period

WATER POLLUTION Water pollution Any chemical, biological, or physical change in water quality (produced through human activities) that contaminates streams, rivers, lakes, oceans, or groundwater decreasing water quality Wastewater Water produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing of clothes and dishes. Fixed spacing

WATER POLLUTION Point source A specific location from which pollution is directly produced. - Easy to identify, monitor and regulate - Factories, oil tankers, sewage treatment plants Nonpoint source A broad, diffuse area that produces pollution. - Difficult to identify and control, expensive to clean - Runoff from cropland, golf course, parking lots, streets, lawns, logged forests

HUMAN + LIVESTOCK WASTEWATER POSES PROBLEMS Problems from wastewater fall into three categories: 1. Oxygen demand 2. Nutrient release 3. Disease-causing organisms

1. OXYGEN DEMAND Biochemical oxygen demand (BOD) The amount of oxygen a quantity of water uses over a period of time at specific temperatures. Dead zone In a body of water, an area with extremely low oxygen concentration and very little life.

  2. NUTRIENT RELEASE Eutrophication A phenomenon in which a body of water becomes rich in NATURAL nutrients. - Caused by increase in nutrients, like fertilizers Cultural eutrophication An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients. -Human activities accelerate input of nutrients, like phosphates and nitrates Eutrophication can cause a rapid growth of algae which eventually dies, causing the microbes to increase the BOD.

GULF OF MEXICO - DEAD ZONE Every year, a "dead zone" appears in the Gulf of Mexico. Area where water doesn't have enough oxygen for fish to survive. Mississippi River delivers a heavy load of nutrient pollution, specifically nitrogen and phosphorus, into the Gulf. 2017 dead zone = biggest one ever measured. Covered 8,776 square miles — area the size of New Jersey. - Adding fuel to a debate over whether state / federal governments are doing enough to cut pollution coming from farms.

3. DISEASE-CAUSING ORGANISMS Throughout the world people routinely use the same water source for drinking, bathing, and sewage. Wastewater can carry a variety of pathogens. Diseases that can be contracted by coming into contact with contaminated water include: Cholera Typhoid fever Stomach flu Diarrhea Hepatitis

DISEASE-CAUSING ORGANISMS Because of the risk that water-borne pathogens pose, we need a way to test for pathogens in our drinking water. Indicator species A species that indicates whether or not disease-causing pathogens are likely to be present. Fecal coliform bacteria A group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful microorganisms associated with contaminated sewage.

TECHNOLOGIES TO TREAT WASTEWATER Treating wastewater properly reduces the risk of waterborne pathogens. Two common ways to handle human wastewater: Septic systems Sewage treatment plants Fixed spacing on botom line

SEPTIC SYSTEM Septic system A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas. Septic tank Large container that receives wastewater from house as part of a septic system. Sludge Solid waste material from wastewater. Septage Layer of fairly clear water found in middle of a tank Leach field Component of a septic system, made up of underground pipes laid out below the surface of the ground.

SEPTIC SYSTEM A septic system. Wastewater from a house is held in a large septic tank where solids settle to the bottom and bacteria break down the sewage. The liquid moves through a pipe at the top of the tank and passes through perforated pipes that distribute the water through a leach field.

SEWAGE TREATMENT PLANTS In developed countries, municipalities use centralized sewage treatment plant that receive wastewater from hundreds or even thousands of households. In traditional waste treatment plants, there are two phases of treatment: Primary - physical process Secondary - biological process Tertiary (Advanced) - bleaching, chlorination

SEWAGE TREATMENT PLANTS The contaminants in wastewater are removed by different unit processes: Primary - Physical process (sedimetation, flotation, screening, filtration) Secondary - Biological process (trickling filters, RBC, activated sludge) Tertiary - Chemical process (chemical precipitation, ozonation, chlorination)

Sewage Treatment Plants A sewage treatment plant. In large municipalities, great volumes of wastewater are handled by separating the sludge from the water and then using bacteria to break down both components.

LEGAL SEWAGE DUMPING Did you know: Raw sewage can sometimes be directly pumped into rivers and lakes? Older sewage treatment plants also receive water from stormwater drainage systems. During periods of heavy rain, the combined volume of storm water and wastewater overwhelms the capacity of the plants Raw sewage overflows occur ~40,000 times/year in the US

ANIMAL FEED LOTS & MANURE LAGOONS Manure from CAFOs is a problem because of volume. It can also contain hormones and antibiotics that are given to the animals.  Manure lagoon Human-made pond lined with rubber built to handle large quantities of manure produced by livestock. After the manure is broken down by bacteria, it is spread onto fields as fertilizers.