Sewage Treatment Plant

A Sewage Treatment Plant (STP) is a facility designed to treat and clean wastewater, commonly known as sewage, which is generated from households, commercial establishments, and industries. The main goal of an STP is to remove contaminants, harmful microorganisms, and pollutants from the wastewater so that it can be safely discharged into the environment or reused for non-potable purposes such as irrigation, industrial processes, or flushing toilets.

The treatment process typically occurs in several stages. The primary treatment involves removing large solids and floating materials through screening and sedimentation. In the secondary treatment, biological processes -

-using bacteria and other microorganisms break down organic matter. The tertiary treatment is an advanced stage where any remaining nutrients, pathogens, or chemicals are removed through filtration, disinfection (often using chlorine or UV light), and other techniques.

Components of a Sewage Treatment Plant

• Screening Unit : Removes large debris like plastics, rags, sticks using metal screens.
• Grit Chamber : Settles sand, gravel, and other heavy particles that can damage equipment.
• Primary Sedimentation Tank : Slows down the flow to let solids settle at the bottom (forming sludge) and grease float to the top (scum).
• Tertiary Treatment Unit (Optional) : Further filters and disinfects the water using chlorine, UV light, sand filters, or membranes.

Benefits :

• Essential for smart cities and eco-friendly housing
• Water supply: Treated sewage can be reused, reducing demand on freshwater sources.
• Health care: Reduces waterborne diseases by removing pathogens from wastewater.
• Environmental cleanup: Prevents pollution of rivers, lakes, and soil.
• Supports regulatory compliance: Meets environmental laws and discharge standards.