Which of the following factors does NOT influence the filtration rate in sand filters?

The filtration rate in sand filters is influenced by several key factors, and it is essential to understand how they impact performance. When considering the effect of filter media age, it's important to recognize that while the condition and characteristics of the filter media can change over time due to factors like clogging or biofilm growth, the age itself does not directly affect the physical filtration rate in the same way that other factors do. In essence, the age might indirectly affect the performance by changing the filter's condition, but it is not a direct factor that influences the rate of filtration as sand particle size, dissolved gas concentration, or water temperature would.

Sand particle size directly impacts how easily water can flow through the filter, affecting the rate at which water is filtered; larger particles may allow for faster flow but less effective filtration, while smaller particles can enhance filtration effectiveness but may slow the rate. Dissolved gas concentration could influence water chemistry and potentially affect particle adhesion or clogging, ultimately impacting the filtration rate. Water temperature affects the viscosity of water, with warmer water typically flowing more freely, thus affecting the filtration speed as well. These factors are fundamental to understanding how sand filters operate effectively, while age primarily plays a role in the overall condition rather than the immediate filtration capacity.