You know what it is like when you are on a plane or train and you have to do some work but a fellow passenger wants to engage you in conversation. 

“What brings you to this part of the world?” they ask. “What do you do?” For me, the quickest way to get back to work is to answer: “I am in effluents and industrial wastewater.” As a conversation-killer this typically does the job. It is 
also a fairly accurate description of what I do for a living.…