“What is this cylindrical shape about 10 meters high with some sort of filter on top?”
“Giant air-vac. It allows air in and out in the event of vacuum or overpressure conditions inside a pipeline while keeping water from escaping the pipeline. It prevents pipeline rupture or collapse due to overpressure or over-vacuum condition.”
What I don't understand is why the downvotes?
"I don't understand it and I am displeased therefore I downvote"
something like that I guess.