Interesting. I note that several of the ideas have come from this forum. But why complicate things...... In the US bob-cat hydraulic deep-well hose re-fitting facilities are readily available.
As for all this talk of evacuation etc etc; they ought to simply flush out the units and pipes, refill, stopper the open ends and.......... Or read how to make a hydro vac and pressure pump for £25 on this forum!