An excellent and well written report. Many thanks for the link. It's a variation -- and apparently a successful one -- of the toilets that were on the Whitney trail (evaporative)but which failed. It would be interesting to compare the designs and why the previous ones failed. Did the Whitney sites just not get enough sun? Are there better sites? Looking at the photos, it's hard to imagine the ones sited in the meadow would be approved today.
The key, as repeatedly stated, is regular maintenance. The use of llamas would also be important. It wouldn't make sense to be packing out 2,500 lbs of human waste while generating that amount or more of stock generated manure and urine using mules.
So, I'm now convinced it's technically possible (Yay!). But I'm still not convinced the cost, aesthetic intrusion of toilets and taking a chance on the long-term ability of USFS to provide maintenance is a justification (vs. wag bags). Building one or two would require an Environmental Assessment (maybe even an EIS).
Getting anything built within a designated wilderness would be a huge struggle. I'm totally winging it, but I would think you'd have to show serious environmental impacts -- such as water pollution and/or impacts as a result of wag bags being used -- that could be mitigated or solved by installing the toilets.
Arguably, you could send maintenance or rangers up every 3 weeks to scour the rocks for abandoned bags and pack them out on a much cheaper schedule and saving the cost of installing the toilets.
But beyond that -- and here dim memories of previous threads on this subject begin to surface -- is why this subject gets so emotionally charged? There seems to be some weird fastidiousness when crapping into a bag that I don't really understand.
Anyway, maybe worth pursuing and very likely useful for other sites (non-wilderness). Just don't see it happening on Whitney.
None of the views expressed here in any way represent those of the unidentified agency that I work for or, often, reality. It's just me, fired up by coffee and powerful prose.