4/1/16 Using Water Wisely

Wait… How much? Only 3% of Earth’s water is drinkable (fresh water) Of that 3%, 75% is frozen in icecaps/glaciers Yet, humans continuously pollute those remaining “available” water sources  Rivers, streams, groundwater

Point-Source Non-point source Pollution that comes from ONE specific site Examples include a sewer pipe, industrial waste from factories Can be controlled because source is identifiable Pollution comes from MANY sources Examples include runoff from gutters, drainage from mines Difficult to control because there is no single source Water Pollution

Point vs. Non Point Pollution

Cleaning Polluted Water Sewage treatment plants are used in most urban and suburban settings  Facilities that remove waste materials from water for cities and towns Septic tanks are used in some suburban and most rural areas  Large underground tank that cleans water from household

Sewage Treatment Septic Tank Protects environment from pollution and humans from diseases Goes through two treatments  Primary: solid objects are caught in a screen; smaller objects can sink and be filtered out  Secondary: water is mixed with (good) bacteria and then disinfected with chlorine Water from household enters tank, where solids sink to the bottom Bacteria at bottom of tank break down these wastes Water leaves tank through buried pipes called a drain field Sewage Treatment Plants vs Septic Tank

Sewage Treatment Diagram

Water Usage in the United States Average household’s use of a 100 gallons of water

Conserving Water at Home Install low-flow shower heads and low-flush toilets Take shorter showers and turn off the water while brushing your teeth Limit watering of lawn and other plants

How Do We Know it is Clean? Scientists determine the “health” of a water system by looking at several factors such as:  Dissolved Oxygen Levels  Levels below 4.0 mg/L can cause stress on aquatic organisms  Nitrate Levels  Compounds composed of Nitrogen and Oxygen; elevated levels are harmful to aquatic organisms  Alkalinity Levels  Water’s ability to neutralize acids; a pH below 6.0 is too acidic  Presence of certain insect larva  Such as stoneflies and mayflies

Industry Agriculture About 20% of water used is for industrial purposes Used to manufacture goods, extract minerals, and generate energy More and more factories are recycling their water Largest use of water in Western U.S.  Ogallala aquifer is largest known in North America  Supplies one-fifth of water  Dropped so low it would need 2,000 years to replenish Most water is lost through evaporation and runoff  New technology has limited water loss Outside the home