I'm attempting to install a new sump pump in my basement after having a few minor flooding incidents and addressing as much of the external causes as possible (gutters, etc). The pump is only used for dewatering the foundation soil; nothing else drains into it.
I live in Rochester NY, which does allow connecting sump pumps to sanitary lines, which is probably the most reasonable option. I could entertain discharging to the outside, but there's not much avenue for that, given the geography and how little land there is around my house.
The sump is located 2 feet to the right in the below picture; discharge tube isn't connected yet. Bottom of the discharge has a standard check valve.
I was wondering what is the correct way to tie the sump discharge into to the sewer stack, pictured below:
Question 1: What would be the easiest place to tie in?
I was thinking of tying into the 2-inch pipe on the left of the picture using a 45 degree wye pointing to the right, given that it has the most pipe to work with and is probably the cleanest to work with. I would run the discharge pipe up the wall on the right, angle it on top of the sill you see at the top of the picture, behind the existing iron-cast pipe, and down next to the 2-inch pipe on the left.
Question 2: Do I need any sort of p-trap? The discharge line has a check valve at the bottom of it, so there should always be a significant amount of water (10 feet) in the discharge riser to prevent sewer gas leaking back.
Question 3: Does the horizontal run of the pipe need to be sloped?
Question 4: Do I need an air admittance valve at the top of the discharge? The large pipe at the top-right of the photo has an air admittance valve about 10 feet off the floor, and I believe the pipe I'm tying into has an AAV, 2 floors up.
Question 5: How much height do I need off of the wye from the 2-inch before I go horizontal? I was planning on cutting into the pipe in the middle just for convenience.