(I got this off of the web)
I'm guessing that you could unscrew the fittings, dispose of the frits, flush out the stationary phase, rinse with hexanes, remove the labels and then recycle the steel?
100 columns disassembly is though. Usually it goes to dry chemical waste unless it was used for biologics or extremely toxic compounds. In the former case it goes to biologics, in the latter-talk to your safety (if available)
Disposal of HPLC columns is very dependent on the industry and company that you work for. In all cases it needs to follow the EHS procedures for your company and location.
The Agilent HPLC column bodies are made of stainless steel and are sometimes internally coated with peek for inertness. The media in the column is made from silica or polymeric particles. Each column has an MDS sheet located here which contains the media and media phase chemical information for the column.
The chemicals that are injected into the column are critical to understand when talking with your EHS department. If the columns are used for biological samples then most likely they will be disposed of through a biohazard process. If they are used for radioactive samples they will need to follow a radioactive disposal process.
If the injected samples are standard chemical samples it is possible to clean the column media of injected sample by flowing a strong solvent through the column then running three times the column volume of DI water through the column. After the media cleaning process the column can be opened up to dispose of the media through a chemical disposal process and the stainless steel column body through a metal disposal process.
Your local EHS department will have the details on proper disposal. Provide them the information above and they will be able to determine the proper disposal process per local regulations and company policies.