Apparently the state of Dubai doesn't have a piped sewage system. Instead, hundreds of sewage tanker trucks collect waste from all over the place and take it to a central processing facility. Apparently the backup of trucks waiting to discharge their loads can be three days long!
Here's a video clip of the extraordinary line of vehicles. LANGUAGE ALERT - the people filming the trucks aren't particularly careful of their vocabulary.
I shudder to think of the stench if one or more of them were to suffer a major collision or accident . . .