| Just few years ago, the word green described | | | | is the cost of maintenance. And those costs are |
| only one thing - a color. Now, it is the name of a | | | | often the burden of the taxpayer. |
| worldwide movement aimed at making the world | | | | Another drawback with ultraviolet water |
| a healthier, cleaner place. Naturally, one of the big | | | | treatment is the lack of a residual effect in the |
| challenges is how to purify water without using | | | | water. Once the water has passed through the |
| chlorine to kill bacteria because some claim it may | | | | ultraviolent unit, and into pipes in the ground away |
| be harmful to the body. And light may hold the | | | | from the light, bacteria can begin to grow again |
| key. | | | | unless the supplier adds a sufficient amount of |
| Although the concept of using ultraviolet light to kill | | | | chlorine, at least 1ppm(1 part per million) to keep it |
| bacteria in water has been around for 75 years, | | | | safe to drink. For now, the hope is that |
| only recently have ultraviolet treatment systems | | | | ultraviolent light disinfection will at the very least |
| been designed and built to do just that. The | | | | help to lessen the amount of chlorine used by |
| process is used frequently as the last step in | | | | suppliers. |
| water a treatment facility before the water is | | | | What about solar? |
| carried through pipes to the end user. | | | | Solar energy captured by solar panels is also being |
| Water passes through a tube inside and ultraviolet | | | | used to help slow the growth of bacteria in water |
| light unit where it is exposed to ultraviolet | | | | storage tanks as well. |
| florescent bulbs. The light from these bulbs is | | | | Bacteria inherent in water will grow if left standing |
| sufficient to kill bacteria almost instantly without | | | | for too long even if chlorine is present. It |
| putting anything in the water. The light source, | | | | becomes stagnant and stale, which renders the |
| however, must be kept clean so that it maintains | | | | chlorine residual less effective and makes the |
| its full bacteria-killing effect. Bulbs can get dirty | | | | water susceptible to bacteria growth. |
| and need to be cleaned or changed or they will | | | | Solar-powered pumps keep water circulating, |
| lose their effectiveness. | | | | which helps maintain the chlorine residual enabling |
| While it is true that the use of ultraviolet light has | | | | the chlorine to kill bacteria. They use no electricity |
| helped modernize the water disinfection process, | | | | and therefore do not pollute nor do they |
| the cost of installing these systems is high and so | | | | contribute to pollution. |