Disposing of hazardous waste indicated by numbers on chemicals
The numbering clearly is not a part of the international GHS (Globally Harmonized System of Classification and Labelling of Chemicals) labeling scheme.

On a side note, GHS requires 


hazard pictograms, 
coded hazard statements (Hnnn and EUHnnn)
coded precautionary statements (Pnnn)


but typically does not give any information on the how/where to dispose chemicals.



For classroom settings, the questions are:


How many different waste containers are needed?
How to label them?
Which chemicals go where?


To my knowledge, a global or EC-wide (European Community) scheme does not exist for this and I'd be astonished to find that the African Union has agreed upon a common scheme.

Instead, this is typically regulated on a nation-wise basis only. 

To give an example: In Germany, the classification scheme is provided by the Deutsche Gesetzliche Unfallversicherung (mandatory accident insurance) and you may find their suggestions for waste disposal in schools here (PDF in German, Stoffliste zur Regel
„Unterricht in Schulen
mit gefährlichen Stoffen“, 2017).

Consequently, without knowing the (national) origin of the source you are citing in your question, it is very difficult to say which number refers to which compound class.