Looking into the history of processing I cannot fully agree.
Hi, which part is in question? Do you mean who did the most research?
Here are several examples... researchers such as (going from memory) Rami Mina and Pedro Quinones of Kodak did research on the use of ion-exchange resins with effluent. Then CPAC, of New York state, built equipment, based on that research. I have personal experience with these systems - one was used to remove (primarily) bromide ion from a color developer (EP2/3) to allow regeneration of the developer overflow (waste). The other was to remove silver from wash water, which normally has too small a concentration for more conventional silver recovery methods. NO OTHER MAJOR MANUFACTURERS PUBLISHED SUCH RESEARCH.
In other silver recovery studies, Austin Cooley of Kodak published numerous papers with respect to optimizing the conditions used for both electrolytic silver recovery and the use of metallic replacement (ie steel/iron wool recovery cartridges).
Fwiw silver in the wash water was a major problem for photofinishers in certain areas. I mentioned wash water ion-exchange systems previously. I oversaw the operation of one such system where we were regulated to something like 0.2 mg/l silver. (As I mentioned, this is an incredibly low concentration with respect to photofinishing.) Our ion-exchange system was able to achieve this when the resin was fairly fresh, but after a number of resin "stripping" and regeneration cycles the effectiveness would fall off.
Kodak researchers came up with yet another technology, called TMT precipitation to achieve much lower concentrations of silver. Because of the expense such a system would be used only for the final "cleanup" or "polishing" of silver-bearing waste. I don't recall who built equipment, but there were small scale machines built, that could be used in a minilab. (But at that point it would have probably been more cost effective to use a "washless" system and simply have the waste hauled off by a licensed waste hauler.)
But the issue pointed out by Maris still remains - WHAT is being done with that waste!? As I have become older I've become more aware of how sneaky and crooked some of our government agencies/bureaucracies are. So when users of community Hazardous Waste pickups, and that sort of thing, DON'T KNOW exactly what happens to the waste, I get suspicious. But I digress.
I could go on and on... I recall having a discussion at an IS&T conference with a young Kodak researcher who had presented a paper on the use of diamond anodes in an experimental electrolysis system for the destruction of photographic waste. I (and and one of my coworkers) were asking, WHY, and WHO would ever use such a system? (Not to mention, what is the mechanism?) Essentially they just wanted to get the results out there, practical or not.
Fwiw pentaxuser would be perfectly justified to call me out on deviating so much from the original topic, and I would agree. I'm guilty (but will probably continue.)