How is Water Processed at a Sewage Treatment Plant?

Water is a necessity of life and is required in various activities. However, after use, this water becomes wastewater, which is harmful to the environment if not processed correctly. Sewage treatment plants play a critical role in ensuring that wastewater is treated and made safe for re-use. In this article, we will explore the process of how water is processed at a sewage treatment plant.

First Stage: Primary Treatment

The first stage of water processing at a sewage treatment plant is the primary treatment phase. During this stage, wastewater is screened for any large objects such as sticks, trash, or debris. The screening process is achieved using screens, and these large objects are removed and taken to a landfill for disposal. The wastewater is then allowed to settle in a clarification chamber, where suspended solids, oils, and grease float to the surface and are removed by skimmers. At this stage, the water is still cloudy and contains harmful pathogens.

Second Stage: Secondary Treatment

The second stage of water processing at a sewage treatment plant is the secondary treatment phase. During this stage, the wastewater is aerated to encourage the growth of aerobic bacteria that digest organic material, such as human waste, pathogens, and chemicals. The wastewater is then moved to a secondary clarification chamber, where the bacteria are allowed to settle to the bottom, and the water is removed from the top. However, some microorganisms are too small to settle, and their removal is achieved using a sand or membrane filtration system. At this stage, the water is drinkable but not yet considered safe for human consumption.

Final Stage: Tertiary Treatment

The final stage of water processing at a sewage treatment plant is the tertiary treatment phase. During this stage, the water is treated with disinfectants such as chlorine, ozone, or ultraviolet light to eliminate any remaining pathogens. The water is then filtered through an activated carbon filter, which removes any remaining chemicals, odors, or taste-causing agents from the water. The final product is safe and pure drinking water, ready for use by humans, plants, and animals alike.

Conclusion

Sewage treatment plants play an instrumental role in making wastewater safe for re-use, thus reducing the burden on fresh water reserves. The process of water treatment begins with primary treatment, where large objects are removed, and the water is allowed to clarify. Secondary treatment follows, where bacteria are encouraged to digest organic material, and finally, tertiary treatment ensures the water is disinfected and filtered, resulting in pure drinking water.