What condition can result from screen equipment being constantly wetted and dried?

The choice that indicates debris can fall off due to the constant wetting and drying of screen equipment is correct because frequent changes in moisture levels cause physical stress on any debris or material that is clinging to the screen. This repetitive cycle can lead to detachment of lighter particles and contaminants, allowing for a more effective removal during operation.

When screens are wet, the adhesion of materials may increase, but upon drying, the bond may weaken, which enables some debris to dislodge and fall off. This process is particularly beneficial in maintaining the functionality of the screens, as it prevents excessive build-up that could impair water treatment processes.

Other choices such as contamination of water, increased efficiency, and build-up of bacteria are less desirable outcomes. Contamination and bacteria build-up can occur if screens remain stagnant with moisture, leading to potential biological growth. Increased efficiency does not directly relate to the physical interaction of debris and moisture changes, while build-up of bacteria is a concern if conditions are right, but constant wetting and drying actually help mitigate this risk due to the physical cleaning effect.