day 3 week 3

#1 ISDS


1.

2. Evaporation- removes dissolved substances
    Filtration- removes nearly all suspended matter
    Bacterial action- converts dissolved organic contaminants into a few simple compounds


3. The properties of aluminum hydroxide are related to the process of flocculation because aluminum hydroxide traps and removes the suspended particles, which is a process called flocculation. Both of these processes are involved in water purification.


4. Calcium oxide is sometimes added in the final steps of municipal water treatment because it neutralizes acidic water, raising it's pH to a correct level.


5. The purpose of flouride being added in the last stage of municipal water treatment is to reduce tooth decay. About 1 ppm of flouride is added to the treatment.


6. The advantages of chlorinated drinking water compared to untreated water is that chlorinated drinking water contains less bacteria.


7. The disadvantage in chlorination is that there are certain substances, that in high concentrations can be harmful to human health, like chloroform which is a substance that is known to cause cancer.


8. Water from a clear mountain stream may require chlorination to make it safe for drinking because  chlorination removes harmful organisms in the water, for example, wastewater.


9. Two alternatives to the use of chlorination in municipal water treatment are charcoal filters, and ultraviolet lights.


18. If water evaporation suddenly stopped, then the Earth's hydrologic cycle would suffer, and other processes would have to be made to make up for the absence of evaporation.


19. The hydrologic cycle, functioning in all three states of water,  (solid, liquid, and gas) wouldn't be able to function if the states of water were not involved.


20. The EPA limits the concentration of THMs to 80 ppb because chlorine can be harmful, but water without chlorine could also be harmful because of the presence of bacteria and other unhealthy substances.


21. The steps in the foul water lab compare with the steps in municipal water supplies because they involve some of the same processes, like filtration. 


22. One day- 1 ppm flouride
     One week- 7 ppm flouride
     One year-  365 ppm flouride