What are the three main processes involved in wastewater treatment?

The three main processes involved in wastewater treatment are primary treatment, secondary treatment, and tertiary treatment.

Primary treatment focuses on the physical removal of solids from wastewater. This typically involves processes such as screening and sedimentation, which help to reduce the load of suspended solids and some pollutants.

Secondary treatment is a biological process where microorganisms break down organic matter. This step significantly eliminates biodegradable materials and further reduces the contaminant load in the water.

Tertiary treatment is the advanced stage of wastewater processing that aims to remove remaining contaminants, including nutrients like nitrogen and phosphorus, which can lead to environmental issues such as eutrophication. This stage often employs methods like filtration, chemical treatment, or advanced oxidation processes to improve the water quality before it is discharged or reused.

Recognizing these key stages helps in understanding the complete cycle of wastewater treatment and the importance of each phase in ensuring water safety and environmental protection. Other options listed refer to processes that either do not specifically apply to the stages of wastewater treatment or represent methods not typically utilized in standard processes. For instance, ozonation and chlorination are disinfection methods rather than primary treatment methodologies.