Tetra Pak cartons are recycled in some countries, although this is a fairly scattered service. As they are composed of cardboard, polythene and aluminium, traditional recycling is not possible.
The cartons are basically soaked to remove the card. The pulp is then used for various paper products. The remaining polythene and aluminium is used in a variety of processes. For example, in Germany it is used as a catalyst in cement production.
Recycling will probably only increase due to public presuure or stronger legislation.
Tetra Pak site