| > | | | | pollutants. Municipal water treatment plants were built |
| In America, there have been different types of | | | | to take care of the problem of filtering the water |
| filtration with varying amounts of success dating back | | | | and making it clean again. |
| since 1892. Today, we have sophisticated methods | | | | Different types of filtration have been tried with |
| of filtering surface water that allow us to be free | | | | varying amounts of success. Back in 1892, there |
| from parasites and other harmful organizms that | | | | were only 27 American cities that provided |
| could threaten our health and well being. | | | | wastewater treatment for their citizens. Now we |
| In the early days of its existence, no one had to | | | | have over 16,000 water treatment facilities spread |
| worry about treating America’s wastewater. | | | | throughout the country. Water filtration starts when |
| Left to nature, the purification process took place | | | | wastewater enters the treatment plant where it |
| slowly but surely. However, now that the population | | | | passes through screens of varying densities. Some |
| has grown by leaps and bounds and more | | | | screens with holes about ½ square remove |
| contaminants are ending up in the water supply, | | | | large debris from the water, while screens with finer |
| steps need to be taken in order to speed up | | | | mesh remove even very small particulates. |
| nature’s cleaning process. The Clean Water | | | | Ion-exchange resins are often used in the water |
| Act of 1972 was designed to provide a basis for | | | | purification process. These are made up of insoluble |
| maintaining the country’s most valuable | | | | beads with a surface covered with highly-structured |
| resource, clean water. | | | | pores where ions are easily trapped and released. |
| Up until the mid 1900s, the nation’s | | | | Ion-exchange resins are used successfully to remove |
| waterways in urban areas were filled with pollutants, | | | | poisons and heavy metals from water. Sometimes |
| but no one was overly concerned about it. Now, | | | | the resins are mixed with an activated-charcoal filter |
| however, we not only realize that clean drinking | | | | in order to remove organic contaminants from water. |
| water is a precious commodity but also that clean | | | | The filtration methods used by municipal water |
| water is imperative to maintaining the ecosystems of | | | | treatment plants are complex. After all, wastewater |
| our world and critical in maintaining national health. | | | | can be filled with microorganisms or pathogens that |
| Cities, then, have became responsible for taking the | | | | cause human diseases. Therefore, the methods |
| steps necessary to treat the wastewater generated | | | | used to clean the water are all important in the lives |
| in their community and ridding it of dangerous | | | | of everyone. |