What should the volume of backwash water used in rapid sand filters not exceed?

The volume of backwash water used in rapid sand filters should not exceed 4% of the total volume of water processed. This guideline is crucial for maintaining efficient filtration while ensuring that the backwash process effectively cleans and rejuvenates the filter media.

Using a backwash volume that exceeds this percentage could lead to problems such as inadequate cleaning of the filter bed, increased water wastage, and the potential for reduced operational efficiency due to the loss of valuable filter media. Keeping the backwash at or below this threshold allows the system to operate effectively while minimizing disruption to the overall filtration process.

By adhering to this practice, operators can maintain the integrity of the filtration system, ensure sufficient velocity for removing trapped contaminants, and manage water resources effectively.