Basement septic lift station-check valve

[Eagle45]

Recently had plumber install lift station for our basement sewage. Inspector noted the following missing reqiuirements from the 2-inch ABS discharge pipe:
-union
-shutoff
-check valve.

My main question is what type of backfow valve to use. I picked up one with a flapper valve inside, but a note that came with it indicates this is for a horizontal installation. So I have another valve (photo attached) that slides right inside the 2-inch ABS. Is this the correct valve to use in this application?
What keeps this type of valve from moving up & down inside the pipe?

Also wondering as to positioning of the 3 missing items. My guess would be, starting at the bottom, the union, then the check valve, then the shutoff at the top? Does it matter what height each is at? I figured the shutoff should be right close to the top where it enters the main sewage line.

For the shutoff, I figured just I would use just an ordinary gate valve?

Thanks in advance.

 

[Redwood]

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