Why should the under drain channel be drained in a trickling filter during periods of shut down?

Draining the under drain channel in a trickling filter during periods of shutdown is essential primarily to prevent odors and insect problems. When water sits stagnant in the under drain, it can lead to anaerobic conditions, which tend to produce unpleasant odors due to the breakdown of organic matter. Additionally, stagnant water can create an environment conducive to the breeding of insects and pests, which can become a nuisance and lead to further operational challenges.

Maintaining proper conditions in a wastewater treatment system is crucial, and preventing the accumulation of unpleasant smells and insects is part of maintaining a safe and healthy environment around the treatment facility. This approach not only contributes to better operational performance when the system is back in service but also to community relations and compliance with environmental standards.