It's really interesting to see the lengths that fracking companies put between themselves and wastewater, basically outsourcing the wastewater manage process to entirely separate companies explicitly for the purpose of no longer being responsible for the wastewater. They've done this pretty much from the start, too.
Actually the reason for that is not as nefarious as you think, and its the same reason for outsourcing construction, operation, commissioning, maintenance and many of the other activities various companies outsource.
The idea is simple. The companies make their money by getting shit out of the ground and selling it. Their value lies in the exploration rights and their proven reserves. Everything else is technical details. Most upstream oil companies are staffed with geophysicists, geologists, and anyone capable of holding a divining rod, as well as a few project managers to hold the whole thing together. They then borrow shitloads from the bank and sink even more shitloads into 3rd parties who will build, maintain and run the equipment. Then they can reap massive profits without having to actually have the expertise to do anything. Ever wonder why BP's oil spill involved a platform owned by someone other than BP, run by someone other than BP, drilling a hole which was cemented by someone other than BP, yet the profits of the operation (were it to have been successful) would have gone to none other than BP?
The entire industry is like that. Wastewater isn't complicated but there are plenty of specialist contractors who are willing to do it for you, so why waste the time and resources to doing it yourself, when you can focus on other things while also partially shifting liability.