What is a high rate sand filter?

A high rate sand filter is characterized by its ability to operate at elevated filtration rates, which is typically measured in terms of gallons per minute per square foot of filter surface area. The correct answer identifies a filter that operates within a range of 12-20 dpm/ft². This range reflects the capacity at which high rate sand filters can effectively remove particles and impurities from water while maintaining adequate water quality and flow rates.

In practice, the design and operation of high rate sand filters allow them to achieve these filtration rates without losing efficiency, making them suitable for various water treatment applications. This capability ensures that they can handle larger volumes of water while still providing effective filtration, which is crucial in both municipal and industrial contexts.

High rate sand filters typically utilize specially designed processes and equipment to manage the increased flow, as the rates in the other provided ranges might indicate lower or even inefficient filtration designs or methods associated with different types of filters. Understanding these operational parameters is essential for environmental health and safety applications, ensuring safe and effective water treatment solutions.