In what scenario should a filter be taken out of service aside from scheduled maintenance?

A filter should be taken out of service if head loss approaches 4.5 feet because this measurement indicates a significant increase in resistance to flow through the filter media. Excessive head loss can lead to inefficient operation, potentially causing inadequate filtration and compromised water quality. By monitoring head loss and taking action when it exceeds recommended limits, operators can ensure that the filter continues to function effectively and that water is treated properly.

In contrast, while changes in the color of the filter media may warrant observation and potentially indicate an issue, it is not necessarily an immediate reason to take the filter offline. Increased raw water temperature might have some effects on filtration but does not on its own necessitate taking a filter out of service. Similarly, detecting odor in the effluent can suggest problems, but it does not automatically indicate that the filter needs to be removed; further investigation is required to identify the source of the odor before acting.