Wastewater treatment is a process used to remove contaminants from wastewater or sewage and convert it into an effluent that can be returned to the water cycle with acceptable impact on the environment, or reused for various purposes. The treatment process takes place in a wastewater treatment plant (WWTP), also referred to as a Water Resource Recovery Facility (WRRF) or a Sewage Treatment Plant (STP) in the case of domestic wastewater. Pollutants in wastewater are removed, converted or broken down during the treatment process.
Types of treatment plants
Wastewater treatment plants may be distinguished by the type of wastewater to be treated, i.e. whether it is sewage, industrial wastewater, agricultural wastewater or leachate.
Sewage treatment plants
It is the process of removing organic based solid substances in wastewater from wastewater by disintegration by microorganisms. At the end of the shredding process, the cleaned wastewater remains on top while the microorganisms settle on the bottom. This system is also called activated sludge system. The most common aerobic biological treatment application is the activated sludge process. Activated sludge processes consist of pre-precipitation pools, aeration pools, final precipitation pools and a disinfection unit. Disinfection is the process of removing bacteria and viruses in the wastewater treatment plant before the effluent is discharged.
Industrial wastewater treatment plants
It is the treatment processes applied to ensure that substances that are dissolved or suspended in water are deposited by changing their physical state. The units of the chemical treatment process are the neutralization section where the wastewater is brought to the appropriate pH range, the coagulation section where the chemical substances that provide the wastewater sedimentation are added, and the flocculation section where the coagulant added wastewater is mixed at the proper rate and the flocculation occurs and precipitation occurs. With the chemical treatment process, parameters such as suspended solids, COD, BOD, heavy metal and phosphorus are removals.