Sewage Treatment – Class 12 | Chapter – 10| Biology Short Notes Series PDF

Sewage Treatment: It is the process of removing contaminants from wastewater and household sewage, making it safe for release into the environment. The process typically includes several stages such as screening, grit removal, primary treatment, secondary treatment, and final treatment, including disinfection. The end goal is to produce treated effluent (water) that meets discharge standards set by environmental agencies and to minimize the impact on water quality and the environment.

A large amount of wastewater is released from the houses and industries every day, they are referred to as sewage. Sewage must be treated in the sewage treatment plants before permitting into rivers and streams to restrict the pollution. Microorganisms are widely used to treat wastewater in sewage treatment. The process of sewage treatment takes place in two stages: firstly, the primary treatment, and second is the biological treatment.

Advantage of Sewage treatment

Advantages of sewage treatment include:

  1. Protects public health: Treated sewage effluent is free of harmful pathogens, reducing the risk of waterborne diseases.
  2. Improves water quality: Treated sewage effluent is cleaner and less harmful to the environment, improving the quality of surface and ground waters.
  3. Reduces pollution: Sewage treatment reduces the release of pollutants and contaminants into the environment, helping to maintain a healthy ecosystem.
  4. Conserves water resources: Treated sewage effluent can be reused for non-potable purposes, conserving fresh water resources.
  5. Supports sustainable development: Sewage treatment helps to maintain the balance of ecosystems and supports sustainable development by reducing environmental degradation.
  6. Supports economic growth: Treated sewage effluent can be used for agricultural and industrial purposes, supporting economic growth and job creation.
  7. Increases property values: Communities with well-functioning sewage treatment systems generally have higher property values and a better quality of life.

Disadvantages of Sewage Treatment Plants

Disadvantages of sewage treatment include:
  • High cost: The process of sewage treatment requires a significant amount of money for building and maintaining the treatment plants.
  • Energy consumption: The treatment process consumes a lot of energy, which contributes to the increase in greenhouse gas emissions and energy costs.
  • Limited capacity: The capacity of treatment plants is limited, and in case of a sudden increase in population or industrial growth, it may become overburdened and unable to treat all the sewage effectively.
  • Environmental impact: The discharge of treated sewage into water bodies can still have negative impacts on the environment, such as the release of nitrogen and phosphorus that can lead to eutrophication and harm aquatic life.
  • Operation and maintenance: The plants need to be properly operated and maintained to ensure that they function efficiently and effectively, and failure to do so can result in the release of untreated or partially treated sewage into the environment.
  • Residuals disposal: The treatment process generates solid waste (sludge) that must be properly disposed of, which can also pose environmental and health risks if not managed properly.