What is one disadvantage of using ozone in water treatment?

• A. It has a high operational cost
• B. It is unstable and decomposes quickly
• C. It produces bad taste
• D. It is not effective against certain pathogens

Answer: (B)

One significant disadvantage of using ozone in water treatment is its instability and the fact that it decomposes quickly. Ozone is a powerful oxidant and is effective in disinfecting water and removing contaminants. However, its half-life is relatively short, which means that it can lose its effectiveness rapidly once generated. This instability necessitates the need for immediate application right after ozone generation, as it cannot be stored for later use. This can complicate the treatment process, requiring efficient and timely operations to ensure effective disinfection.

The other choices highlight potential concerns associated with ozone use, but they do not define its main disadvantage as accurately as the instability factor. For instance, while ozone can contribute to taste and is costly operationally, these aspects are often outweighed by its effectiveness. Additionally, although ozone is effective against a wide range of pathogens, some resistant strains may not be completely eliminated, but this is not as critical to operational considerations as the rapid decomposition rate of ozone itself.