living organisms on Earth. State and federal laws regulate wastewater treatment to protect human health and the environment since the Clean Water Act of 1972 was enacted. Wastewater treatment facilities serve this purpose and thanks to them, serious waterborne diseases such as cholera and diphtheria are prevented.
Water entering wastewater treatment facilities contains waste from residential, commercial, and industrial sources. On average, it consists of 99.94% water and 0.06% waste. Some examples of such waste are human waste, food, dirt, soap, personal care products and other chemicals. After the treatment, water can be returned to rivers to be used again and again downstream. The treated wastewater must be suitable to support the primary ecological function of rivers as a habitat to various aquatic organisms, provide spawning opportunities to fish, or supply water to agriculture and industries.
The main processes of wastewater treatment plant
- Wastewater from toilets sinks, tubs, and washing machines passes through bar screens to remove larger debris.
- The water then enters primary clarifiers where solids settle to the bottom of the tanks.
- Next, the water undergoes biological treatment where microorganisms break down organic materials.
- The water is then disinfected to remove any remaining bacteria.
- At this point, the water is ready to be discharged to lakes, streams, and rivers, or to be used for irrigation. But to make it suitable for drinking requires a few more steps.
- The treated water passes through filters that remove the tiniest of contaminants, like viruses or pharmaceuticals, by reverse osmosis.
- Finally, ultraviolet is used to fully disinfect the water by scrambling the DNA of microorganisms that might still be living in it.
- The highly treated water is now pure, clean, and suitable for distribution.
Have a look at this infographic to get better understanding of how wastewater is treated, and why you should conserve water at home.
The source of the infographic: http://www.biopro.ie/
The text is written by Jenny Travens.