How does the rate of decrease of filter head loss indicate filtration effectiveness?

The rate of decrease of filter head loss is a significant indicator of filtration effectiveness as it reflects the success of both pretreatment processes and the filtration itself. When a filtration system operates effectively, the buildup of particles and other contaminants within the filter media results in a rise in head loss, which is the pressure needed to push water through the filter.

As the filter media becomes overloaded and starts to clog, there will be an increase in head loss. However, if the head loss decreases over time after a backwash or during optimal filtration conditions, it suggests that the filter is performing well. This decrease indicates that the particulates are being effectively removed from the water, allowing it to flow through the filter with less resistance. Hence, monitoring the rate of head loss provides valuable insight into the filtration system's ability to maintain clean and clear water output, confirming the efficacy of both pretreatment measures (like coagulation and sedimentation) and the filtration process itself.