The Official 'Zonju V Secrets' thread *SPOILERS*
There are two (2) secrets on this level. Both are related to the big building near the center where there are two elevators, up elevator on one side and down on the other.
#1 - you are on a catwalk below the catwalk that has a pipe under it. The elevator you can't switch from there is to your right. In front of you is what looks like a bulkhead which you can make a double jump to get to the top of, and collect some booty - check it with Sense if there is any question.
#2 - go inside that building, and take the elevators all the way to the top. There are two window switches - one works and the other is fried. The working one opens the windows and you can walk the ledge around to where there is just the thin round pipe below you that leads to the building with the Comm equipment on top. Do a controlled fall down to the pipe (one level at a time) and cross it to collect some more goodies. When you cross back, you should continue dropping down ... it's safer.
Dopelar effect (n.) The tendency of stupid ideas to seem smarter when they come at you rapidly.