The course on introduction to environmental engineering (ciee e4252) is one of the few I have taken at Columbia in three years that actually focuses on actual environmental engineering. Chandran actually is able to convey some very complex concepts in a very clear manner I beginners (although I think there were some Grad students in the class). There are lot of real world examples and the course also stresses the importance solving real problems. Lectures are very interactive and the professor encourages conversation during class. Textbook might look scary, but you will only cover the most important material. As long as you come to lecture and do the assignments you should be fine. There was a field trip mentioned but in the end we ran out of time.