I feel that this is a good place to discuss remediation techniques for polluted landscapes.
There are many different methods which have already been developed, and many more are being researched. Bio-remediation, myco-remediation, and ecosystem restoration can all be used to restore large scale damaged ecosystems.
Recently I found out about the quarry life project. It is a group which collected research from around the world on how to restore quarry life. The projects are here: