SOP For disposal method for disposing of microbial cultures s is described in this post which you can follow in the section of  microbiological lab. 

Objective:

This procedure has been established for disposing of microbial cultures.

Scope:

This procedure is applicable to microbiology lab.

Responsibility:

Microbiologist.                              

Accountability:

Quality Control Manager.             

Procedure:

Before disposing of the culture media used in microbiological testings first of all collect and wrap the media properly in aluminum foil and then final pack in polyethylene and autoclave the media  at 121°C /30 minutes/15psi. 
After autoclavation drain the liquid media into the sink under running tap water. 
Soak the empty glasswares in chromic acid solution for 2hr and then wash the glasswares and dip in 70% IPA Solution for 30minutes and then rinse with tap water and finally rinse with purified water and dry.

Allotment of load/batch number to disposal activity: 

Everytime when disposal activity is performed a load/batch number must be given.  

Disposal Number must e given in the following manner.

XXX/YYY/ZZZ
Where XXX indicates the year in which activity is performed e.g. 2022
YYY indicates the abbreviation of activity performed. e.g. disposal of used media (DUM).  

ZZZ indicates serial number e.g. (001) 

NOTE: Always use protective gloves, goggles, overall and face mask while performing the disposal activity. 
Always run an autoclavation activity with empty chambers at 121°C /30 minutes/15psi after the sterilization of used media. 
At the end of activity record the results in respective logbooks i.e. (Autoclave logbook, chemical/biological indicator logbook and disposal of used media logbook)