hi! other responses are more than welcome, but you can get started on some very brief info in this thread

The Berlin Airlift moved vast amounts of materiel into the city. What happened to the waste the city produced?

This is a map of West Berlin. As you can see theres quite a bit of open area in it. It wasnt 100% building. Thus, airlift or no airlift, there was definitely some space if required.

http://37.media.tumblr.com/1365591fac83d4054aa503a713bfa701/tumblr_mpbz06iPB21qzs1dro1_1280.jpg

Furthermore. This page here has substantial detail on the issue in its first paragraph. http://www.berlin.de/mauer/mauerweg/schoenefeld_lichtenrade/index.en.php

I used "west berlin garbage dump" in google to find it. to find it. Dörferblick seems to be a garbage hill from around that era.