Which statement concerning ozone is incorrect?

The statement that all statements are correct cannot be valid, as it implies there is no incorrect information among the other options concerning ozone. Each of the other statements contains factual information about ozone's characteristics and applications in disinfection and water treatment.

Focusing on the other statements: Ozone indeed has a strong residual that can last for several hours in certain conditions, making it effective but variable depending on the treatment context. Ozone is recognized for its rapid disinfection properties, often outperforming chlorine in terms of speed of pathogen inactivation, particularly for certain microorganisms. Additionally, the cost factor is significant; ozone treatment systems typically require a higher initial investment and operational costs compared to conventional chlorine treatment, which is widely used and usually more economical.

Given this understanding, asserting that all statements are correct is inaccurate because at least one assertion must be incorrect for the initial question to hold true. A careful examination of each statement reveals that there is more nuance and context to consider, leading to the conclusion that not all statements can be correct simultaneously.