Effluent Treatment Plants

Description

An ETP (Effluent Treatment Plants) is a process designed for treating the industrial waste water for its reuse or safe disposal in the environment. Treatment Levels & Mechanisms of ETP.

• Treatment levels: preliminary
• Primary - Physical separation of big - sized impurities like cloth, plastics, wood logs, paper, etc. Common physical unit operations at preliminary level are:
• Screening: A screen with openings of uniform size is used to remove large solids such as plastics, cloth, etc. Generally, a maximum of 10mm is used.
• Sedimentation: A physical water treatment process using gravity to remove suspended solids from water.
• A Clarification: Used for separation of solids from fluids.

Chemical unit processes

• Chemical unit processes are always used in physical operations and may also be used with biological treatment processes.
• Chemical processes use the addition of chemicals to the wastewater to bring about changes in its quality.
• Example: pH control, coagulation, chemical precipitation and oxidation.

Secondary: - Biological unit process

• To remove, or reduce the concentration of organic and inorganic compounds.
• The biological treatment process can take many forms, but all are based around microorganisms, mainly bacteria.
• Aerobic treatment processes take place in the presence of air (oxygen).
• Utilises those microorganisms (aerobes), which use molecular/free oxygen to assimilate organic impurities i.e. convert them into carbon dioxide, water and biomass.

Tertiary (or advanced)

A final cleaning process that improves wastewater quality before it is reused, recycled or discharged to the environment.