A basic question: Are there specific definitions for preliminary tests, small-scale tests, medium-scale tests, etc.?

A basic question: Are there specific definitions for preliminary tests, small-scale tests, medium-scale tests, etc.? Or what is the criterion for classification? Treatment water volume? Also, are these words used only for the period from the emergence of a new process to its official adoption? My personal understanding: Most tests are aimed at industrial wastewater. Determine which water and what treatment process are appropriate. Because not every type of wastewater can be treated using the same method. After all, given its complexity, it’s difficult to master; after all, it is experiments that provide conclusive evidence. For the initial stage: for example, when given a project related to industrial wastewater, one needs to recommend several treatment methods based on theory and experience, and then through experiments select 1-2 processes that offer good treatment results and other favorable characteristics. Generally, this is sufficient for treating small to medium-sized amounts of wastewater.