BroadfordingScience

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_{Date Published: 11 December 2023}

Water Treatment System

Wonjae Lee and Younghyun Lee

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On November 13th, high school science students at Global Vision Christian School Broadfording went on a field trip to the Hagerstown Water Treatment Plant. The students went to the water supply facility and the sewerage arrangement of the water treatment plant and learned the general processes of the water treatment system.

Water is the most essential element for most of the biological organisms. Water can keep temperature, protect the spinal cord, and get rid of waste through urination, perspiration, and bowel movements. When it comes to using water, proper water treatment is crucial. Water treatment is a process of various types of operations that removes contaminants and hazardous substances from the water. The aim of water treatment is to eliminate contamination or non-desirable characteristics of water. There are two main types of water treatment: waterwork and sewerage.

Waterwork is a system of buildings and pipes in which a public supply of water is stored and treated from which it is sent out. It transports water from treatment facilities to the public. During filtration, clear water passes through filters that have different sizes and of different materials by using chlorine. These filters remove dissolved particles and germs, such as dust, chemicals, parasites, bacteria, and viruses. It supplies usable water, discharges used water, and purifies water to make it reusable.

Wastewater, known as sewage, is the polluted water generated from industrial processes, human activities, or rainwater runoff. Since the wastewater has contaminants, its treatment separates these pollutants from the wastewater, leaving an effluent that has no negative impact on the environment. Sewage can be treated in three phases: primary, secondary, and tertiary. 

Primary treatment is the removal of a portion of the suspended solids and organic matter from the sewage. It allows sewage to pass through a basin where heavy solids can settle to the bottom, while oil, grease, and lighter solids float to the surface. The settled and floating materials are removed, and the remaining liquid may be discharged or subjected to secondary treatment.

Secondary treatment is the removal of biodegradable organic matter from sewage or wastewater. This biological process can be done with either a suspended growth or a biofilm process. This treatment can also be processed through aerobic or anaerobic to reduce organic matter. In contrast to the primary treatment, which removes solids and organic matter in the general process, the secondary treatment removes them in specific biological processes.

Tertiary treatment is the advanced sewage treatment to improve the effluent quality before it is discharged to the receiving water body or reused. If disinfection is practiced, it is always the final process called effluent polishing. Tertiary treatment may include the removal of biological nutrients, disinfection, and micropollutants, such as environmental persistent pharmaceutical pollutants. 

Sewerages utilize the methane gas generated as a substitute for natural gas, serving as an alternative energy source. The energy produced during the incineration process is commonly harnessed to power the operation of the treatment facility. Furthermore, the residual sediment, after treatment, is often repurposed as resources for fertilizers, cement raw materials, and dry materials, contributing to the creation of sustainable future value for a clean environment. Following meticulous sewage treatment procedures, water released into rivers embarks on an extensive natural purification journey within rivers and seas. After undergoing this intricate process, it transforms into freshwater. This completes a holistic cycle in the journey of water treatment.

Just like the water supplied to households, wastewater undergoes purification processes as well. Despite the complexity of these procedures, tap water in the United States undergoes water quality testing for approximately 300 items, surpassing the 164 criteria recommended by the World Health Organization. 

While water shortage does not seem imminent, it’s essential to recognize that there are nations facing water scarcity. Therefore, fostering an appreciation for water resources and adopting a conservative mindset is crucial. To emphasize the significance of water, the 47th UN General Assembly, inspired by the Rio Environmental Conference in Brazil in 1992, declared March 22 as World Water Day. This annual commemoration serves as a reminder to reflect on the preciousness of water resources and encourages individuals to take action towards their preservation.