We live outside the city limits, and have a sewerage treatment system.  Originally we had 8 very large ligustrums planted around the sewerage treatment plant, but they were starting to encroach onto the driveway, so we moved them.  Some we put along the back property line, and some we put along the East property line.  I wanted to plant something to camouflage the sewerage treatment plant after moving these shrubs.  I decided to put some irises, as the roots are fairly shallow, and if necessary, they can be moved fairly easily.