It's interesting work with a wide variety of designs and materials used. I've worked on wood, concrete, prestressed concrete, steel and aluminum. You're given a large latitude as long as your designs meet the intent of the process (and don't fall down). Plants, especially wastewater, tend to be built in areas with challenging soil conditions.
The downside is that it's tough to break into management, if that's your goal. You're going to have to work for environmental engineers. But they're terrified of anything structural, so they usually leave you alone.
