Planet Earth has often been called a “water world,” and for good reason. It is well-known that three-quarters of the Earth’s surface is covered with oceans and other bodies of this liquid, from the Great Lakes of North America to Lake Chad to the Caspian Sea. But there’s only so much to go around. Out of all of that, only 3% of it is fresh (non-salty), and 1% of it all is fit to drink. There are plenty of thirsty mouths on the planet, not to mention industrial use for fresh water. Keeping that liquid clean and usable is more important than ever, and there are several methods on hand.
What Goes in the Water?
Even though it is “fresh,” many natural and man-made contaminants means there is polluted water everywhere. Some species of bacteria are common in contaminated liquid, such as salmonella. This disease enters a system via animal waste, and can cause multiple symptoms such as cramps and fever, according to Global Hydration. Hepatitis A is another liquid-borne disease in the United States, entering the system through infected human waste that is carried by damaged sewer systems of overflows.
Ground water can also become polluted, but remediation services are available. It makes up 95% of fresh water, and according to Industrial Environmental Contraction, dirty water results from fertilizer, pesticides, leaked materials from landfills, and industrial spills. This contaminated water is no doubt useless for drinking or commercial use, so groundwater environmental services come into play. One method is a physical one: pumping water up, treating it with chemicals or biological agents, then returning it. Or, the it can be left in its natural place and loaded with biological or microorganism agents directly, destroying the industrial chemicals polluting it. Chemical treatment is also possible, using oxidation, ion exchange, or carbon absorption.
A water treatment plant can also handle polluted water. This facility begins the process by drawing liquid from a lake, river, stream, or other natural source. According to Interesting Engineering, the treatment plant will place coagulant chemical agents into the water to form large clumps and granules of pollutants. Once this liquid enters a sedimentation basin, the large particles of impurities settle and are left behind when the process moves on.
Next, a sand filter is used on the smaller particles and bacteria, and typically, the water flows from the bottom of the sand filter and through the top, even cleaner than before. Some bacteria will remain, however, and chemicals, such as chlorine-based compounds, are used to kill off whatever bacteria are left. In fact, chlorine treatment is present beyond the treatment plant, often found in a city’s pipes to prevent more bacteria from entering. Ultraviolet radiation is another option, since the radiation damages the bacteria’s DNA and renders them incapable of reproduction, so they are alive but harmless when consumed. However, this treatment only works at the plant, and does nothing to prevent bacteria from entering the water through pipes.