Question

11 multiple choice 1 point what is the purpose of an educter? to clean screens to introduce chlorine gas into water for disinfection to backflush filters to ensure that water stays in a liquid state 12 multiple choice 1 point what procedure is used to remove accumulated contaminants that plug a sand filter? sifting raking back flushing replacing the filter

Explanation:

For question 11: An eductor (in water treatment) uses fluid dynamics to create suction, which is used to backflush filters by reversing flow and dislodging trapped particles. The other options do not match its core purpose.
For question 12: Back flushing involves reversing the flow of water through a sand filter, which dislodges and flushes out accumulated contaminants that clog the filter media. Sifting, raking, and full filter replacement are not standard procedures for this issue.

Answer:

1. To backflush filters
2. Back flushing