What filter needs to be backwashed during a long-term shutdown?

During a long-term shutdown, a multimedia filter needs to be backwashed to ensure that it remains in good working condition and does not become fouled or clogged over time. Multimedia filters are designed to remove various types of particles from water through multiple layers of different media, making them highly effective for filtration.

Backwashing is a crucial maintenance procedure that involves reversing the flow of water through the filter to dislodge and flush out accumulated contaminants. This is particularly important during prolonged downtime, as stagnant water can lead to bacterial growth and biofouling, which can compromise the effectiveness of the filter when it is put back into service. Regular backwashing helps maintain the structural integrity of the filter media and ensures clear water flow when the system is restarted.

The other options, such as RO vessels and bag filters, do not typically require backwashing during a long-term shutdown. RO vessels often involve a different maintenance protocol focused on preventing membrane fouling through chemical cleaning or maintaining system pressure and conditions. Bag filters, while requiring maintenance, are usually replaced rather than backwashed due to their simpler design and function. Hence, focusing on the multimedia filter and the specific needs it has during a shutdown highlights the importance of maintaining system performance and ensuring effective filtration upon resuming operations.