I'm so glad you're thinking of these terrific professions. I really enjoy teaching at the university level, in civil engineering. Civil engineering makes good use of chemistry expertise, through its sub-discipline of environmental engineering (as well as materials and pavement engineering, for example). You'll notice that most departments of civil engineering are now titled Department of Civil and Environmental Engineering -- so your joint interests will fit in very nicely! Environmental engineering emphasizes water, air and soil quality and contamination. You could be modeling air pollution outside or in a home, ground water flows from a reservoir, drinking water quality, remediation (clean-up) techniques, and so forth.
Of course, a Department of Chemical Engineering is another option that also will marry your two interests. (There the focus tends to be much more microscopic, at the level of atoms, and how molecular reactions proceed, I believe.)
Good luck with your quest! Let me know if you have further questions.