There are vertical "shaft graves," also known as "pit graves," also known as "vertical pits," all over Ireland and in fact all over Europe. Each pit is a deep hole lined with bricks, then inside lined with plaster.
If refuse (including human waste) is put in it, it is known as a "waste pit."
If water starts seeping through while it's being dug, it is finished off as a "well."
If it is blessed and used for the interment of the mortal remains of a person or persons who have died, it is consecrated as a "grave."
The point being that these things are, structurally speaking, practically identical, distinguished only by use. And there is no way on God's Green Earth that nuns would have "thrown" or "dumped" bodies into a septic tank. They were interred in consecrated ground.
The ignorance --- and malice--- evinced in these "septic tank" articles is just astounding.
I couldn’t believe that any serious sister would purposely put bodies in a sewer or latrine. And neither did the author of the lead article, even though he was skeptical about nuns. I thought that possibly confusion could have arisen and the sisters thought the facility was something other than what it was currently configured to be. Although, active use as a sewer certainly would have produced an unmistakable smell that would not be the same as the smell of a mausoleum.
Anyhow, if questions are arising, someone trustworthy ought to investigate and settle the question. And if a genuine mistake was made, appropriate prayers be made or whatever it takes to satisfy people that proper reverence was paid to God concerning the bodies of the deceased.
But panicking like the sky had fallen hampers any kind of sane resolution.
And yes there does seem to be some flavor of “Oh those dastardly Catholics, we finally caught them.” That has no class. For segments of Christendom to hoot that the other segments are devoid of Christ and ought to be treated that way, is just blind bigotry. The Lord lets it happen, but it does not please Him.