Peeponics is a common method to start cycling of an aquaponic system. I've done it myself. One of the tricks is to bottle the pee for several days. Over those days the pH of the pee will rise dramatically and produce ammonia (which will help feed bacteria in the AP system). At the same time, this highly alkaline environment kills off bugs that may be present.
Technically, I can't think of a reason you couldn't do this indefinitely, but the freak-out factor is pretty high.
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