Effluent Treatment Plant
Collection and treatment of industrial waste water along with purifying and returning the extracted water back to the environment is an important aspect to resource conservation and public health and safety. With the growing industrialization, urbanization and population, effluent treatment plants are becoming a necessity.
ETP (Effluent Treatment Plant) is a process design for treating the industrial waste water for its reuse or safe disposal to the environment. These processes act as barriers to eliminate different types of waste and chemical contamination. The untreated industrial waste water is known as influent and the treated industrial waste water that leaves the ETP is called the effluent. The waste extracted from influent during the processing is called sludge.
Some of the major reasons for using ETP’s are:
- To clean industry effluent and recycle it for repeated or further usage
- To reduce the usage of fresh / potable water during industrial processing.
- To reduce the costs incurred on procurement of water
- To meet the Standards for emission or discharge of environmental pollutants from various Industries set by the Government and avoid compliance related and environment compensation related penalties.
- To safeguard environment against pollution and contribute in sustainable development.
A typical effluent treatment plant works in following stages
Preliminary Stage: The purpose of this stage is for physical separation of big sized impurities like threads, cloth, plastics, wood logs, paper or any foreign objects. The commonly used techniques at this stage are Screening, Sedimentation or
Primary Stage: This stage involves the removal of floating and settleable materials such as suspended solids and organic matter. The techniques used in this stage are a combination of physical and chemical methods. Chemical processes use the addition of chemicals to the wastewater to bring about changes in its quality in terms of pH control, coagulation, chemical precipitation and oxidation.
Secondary Stage: This stage comprises the use of biological and chemical processes. Most of the biological processing are based around microorganisms, mainly bacteria and could be Aerobic or Anaerobic.
Tertiary Stage: Final cleaning process that improves wastewater quality before it is reused, recycled or discharged to the environment. This stage removes remaining inorganic compounds and substances, such as the nitrogen and phosphorus. Bacteria, viruses and parasites, which are harmful to public health, are also removed at this stage so that the treated output can be put to its intended usage or discharged safely into the environment.