Washer Drain Hose + Sump
When I bought my house, the washing machine would drain into the sump, and them be pumped into the sewer. Since this is not up to code in my county, and if waste water from the laundry sat in the sump for too long it would begin to smell, I decided to try my hand at correcting the issue by add a "T" so the sump pump and washer drain hose would each have their own access to the sewer line.
In doing so I now hear a slow air hiss after water from either the sump or washer has been pumped into the sewer and the pumps on either have stopped. The hoses for both also seem to retain a bunch of water after the pumps stop.
I've attached a picture of what the new configuration looks like.
The sewer pipe (yellow at the bottom of pic) is about 4 feet off the floor extending from the wall, the black top hose is from the sump as I've run the hose up and over to the sewer, and the gray washer hose is up and into the right.
Questions. 1) Is this a fair/correct configuration? 2) Should some water remain in the lines after the pumps have stopped? 3) Does elevating the hoses add any value/help to prevent a backwash? 4) How can I eliminate the hiss? And if this means a relief hole, where would I put that in the "T".
Thanks in advance for your time and assistance.