There are several ways to find a particular question in the Quest repository of Questions based upon the information you are given by the instructor.
Option 1 - Instructor want to know what questions are available in their area
I was able to find your question in the Quest editor
https://quest.cns.utexas.edu/editor/main
Environmental Engineering
Chapter - Water and Waste
Section - 16. Secondary Treatment .....
Instructor Wiki - Browse Questions for a Chapter
Option 2 - Instructor has the title of the question but can not find it
Go to editor, enter in the name in the appropriate search field, ensure it’s the correct question that comes up. Click on banks tab to see where it’s stored
Option 3 - Instructor has the Question ID number but can not find it
Here is the link to the question
https://quest.cns.utexas.edu/editor/draftitems/edit?itemversion=233235&tab_0=undefined
You can use the link above to find any question after logging into Quest by substituting the 233235 with the Question ID number you are searching for.