Recycling programs are, of course, a major thing that college campuses can do. However, there are other things that they could do to contribute to a more sustainable environment.
One thing to do is to change how they deal with much of the trash that they do throw out. In particular, they could change how they deal with food scraps. Colleges produce large amounts of such things. Those could be composted and used to naturally improve the soil in areas such as flower beds on campus. This would reduce the flow of garbage to landfills and help reduce the amount of chemicals used by the people in charge of landscaping.
A second possibility would be to create things like “green roofs” or to put solar panels on the tops of buildings. Solar panels would capture the sun’s energy and could be used to do things like heating the buildings. Green roofs would help to insulate buildings. They would also capture precipitation instead of allowing it to run off into storm drains. Green roofs also lower the temperature (in the summer) in their immediate vicinity because they do not capture and radiate the sun’s heat.
A third possibility would be to change to much more of a paperless system. Professors could, for example, require many or all kinds of homework to be handed in electronically. This would dramatically reduce the amount of paper being used on campus.
All of these would be things that a college could do that would lessen the impact that its campus has on the environment.