Which process is listed as part of pretreatment in surface water treatment?

Which process is listed as part of pretreatment in surface water treatment?

• A. Desalination
• B. Filtration
• C. Disinfection
• D. Chemical oxidation

Answer: (D)

Pretreatment prepares water for the main treatment steps by adjusting and removing contaminants so downstream processes can work more effectively. Chemical oxidation fits this role because it chemically alters or breaks down substances that would hinder subsequent removal, such as color-causing compounds, taste and odor compounds, natural organic matter, and iron or manganese. For example, oxidants like potassium permanganate or ozone can oxidize metals and organics, making them easier to filter and harder to form disinfection byproducts later. Filtration and disinfection are typically considered later stages: filtration removes particulates, and disinfection inactivates pathogens after filtration, while desalination is a separate, extensive treatment step. So chemical oxidation is listed as part of pretreatment because its purpose is to modify contaminants before the primary treatment steps.

Pretreatment prepares water for the main treatment steps by adjusting and removing contaminants so downstream processes can work more effectively. Chemical oxidation fits this role because it chemically alters or breaks down substances that would hinder subsequent removal, such as color-causing compounds, taste and odor compounds, natural organic matter, and iron or manganese. For example, oxidants like potassium permanganate or ozone can oxidize metals and organics, making them easier to filter and harder to form disinfection byproducts later. Filtration and disinfection are typically considered later stages: filtration removes particulates, and disinfection inactivates pathogens after filtration, while desalination is a separate, extensive treatment step. So chemical oxidation is listed as part of pretreatment because its purpose is to modify contaminants before the primary treatment steps.