What is the recommended backwash rate for high rate sand filters?

The recommended backwash rate for high-rate sand filters is typically around 15 gallons per minute per square foot (gpm/ft²). This rate is effective for dislodging dirt and contaminants from the filter media, ensuring that the system operates efficiently. Backwashing at this rate allows for adequate flow to lift the sand and create the necessary turbulence to flush out accumulated debris while minimizing the chances of damaging the filter media.

Higher backwash rates, such as 25 or 30 gpm/ft², while effective in some scenarios, can disturb the sand bed too vigorously, potentially causing sand loss and compromising the filter's integrity. It is essential to adhere to the appropriate backwash rate recommendations to maintain optimal filtration and prolong the lifespan of the filter system.