1. Diagram of the hydrologic cycle:
2. The three major process that occur in natural water include evaporation from ocean water or other water sources. This process leaves behind dissolved heavy metals, minerals, or molecules. The next step is when bacterial action converts dissolved organic contaminations into a few simple compounds like water or carbon dioxide. The third major step is when water seeps further into the ground to that is filtered through sand and gravel that remove almost all suspended matter.
3. The properties of aluminum hydroxide are related to the process of flocculation because they trap and remove suspended particles and moves them to the bottom.
4. Calcium oxide is sometimes added in the final step of municipal water treatment because it is a basic substance and can neutralize acidic water to raise its pH to a proper level.
5. About 1 ppm of fluoride is added to the last stage of the water treatment plant to reduce tooth decay.
6. The advantages to using chlorinated drinking water compared to untreated water is that chlorine kills disease-producing microorganisms.
7. Yes, there is a disadvantage to using chlorination in water treatment because chlorine in water can react with organic compounds produced by decomposing animal and plant matter to form substances that can be harmful to humans. One example of this is THM which is a substance known to cause cancer.
8. Water from clear mountain streams may require chlorination to make it safe for drinking because the water can contain harmful bacteria, such as feces left by animals, and heavy metal ions.
9. Two alternatives to the use of chlorination in municipal water treatments include charcoal filtration and and the use of ozone.
18. If water evaporation suddenly stopped, then Earth's hydrologic cycle wouldn't work. Evaportation is the first step to the hydrologic cycle. Without it water would not enter the clouds containing just water and leaving behind dissolved heavy metals, minerals, or molecules. At this process water also turns into a gas as water vapor.
19. The hydrologic cycle would not be able to occur if water wasn't able to turn into water vapor (gas), or fall as precipitin (rain or snow) and then turn back into water. The hydrologic cycle wouldn't function the without it's three physical states (solid, liquid, gas).
20. EPA limits the concentration of THMs to 80 ppb instead of requiring their total elimination from municipal water supply because THMs is a chloroform, a substance known to cause caner, but it also cant be eliminated because chlorine is needed to kill bacteria.
21.The process used in the foul-water investigation are similar to steps in the natural purification of water because when water seeps into the ground and passes through gravel, sand, or rock; this demonstrates filtration that was used in both the foul- water lab and the natural purification.
22.
a. one day: 1 ppm of fluoride
b. one week: 7 ppm of fluoride
c. one year: 365 ppm of fluoride
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