Wastewater treatment is a process used to remove contaminants from wastewater or sewage and convert it into an effluent that can be reused or returned to the water cycle with minimum impact on the environment.
Normally, the treatment process happens in a Water Resource Recovery Facility (WRRF) also known as a wastewater treatment plant (WWTP) or sewage treatment plant.
Here the pollutants in municipal wastewater are removed or broken down in a process that generally takes place over three stages: primary, secondary and tertiary.
During primary treatment, wastewater is temporarily held in a settling tank where heavier solids sink to the bottom while lighter solids float to the surface.
Once settled, these materials are held back while the remaining liquid is discharged or moved through to the more rigorous secondary phase of wastewater treatment.
These large tanks are also often equipped with mechanical scrapers that continually drive collected sludge in the base of the tank to a hopper which pumps it to sludge treatment facilities.
Completing secondary wastewater treatment allows for safer release into the local environment, reducing common biodegradable contaminants down to safe levels.
Secondary treatment of wastewater works on a deeper level than primary and is designed to substantially degrade the biological content of the waste through aerobic biological processes, such as:
- Biofiltration — A process that uses sand filters, contact filters or trickling filters to ensure that any additional sediment is removed from the wastewater.
- Aeration – This is a long process which increases oxygen saturation by introducing air to wastewater. Typically, the aeration process can last for up to 30 hours — but it is very effective.
- Oxidation ponds – A warmer climate process, this method makes use of natural bodies of water such as lagoons, allowing wastewater to pass through for a set period before being retained for two to three weeks.
The tertiary wastewater treatment process is to raise the quality of the water to domestic and industrial standards, or to meet specific requirements around the safe discharge of water. In the case of water treated by municipalities, tertiary treatment also involves the removal of pathogens, which ensures that water is safe for drinking purposes.
Want to learn more? Tonex offers 2-day and 3-day
Want to learn more? Tonex offers 2-day and 3-day Water and Wastewater Treatment courses.
Additionally, Tonex offers nearly 400 classes, seminars and workshops in close to four dozen categories of systems engineering training.
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