Hello all, I've got a sewer gas problem in my basement and need some advice on how to prevent it from getting in :( The drain is 6" internal diameter inside the pipe..not at the surface. I can take another picture with the measuring tape inside if I need to. It appears to be a clay pipe, but I can test with a magnet to see if it's metal I guess..We have two pvc drain pipes dumping into this drain and every time water is flowing into it, the sewer smell comes out. The pvc drains are from a dump sink and an AC condensate pump so it's just water or sometimes some handsoap being dumped in there. The washing machine drain is connected into this below the concrete as well. There doesn't appear to be any J or P or any kind of trap to prevent sewer gas from coming up. I can't afford to have someone come dig it up and put in a proper trap, so I'm wondering what products are available for this if at all? I found a SureSeal Inline Floor Drain Trap Sealer but they only go up to 4"! that looks like it would be exactly what I need. The first picture shows the drain and the two pvc drain pipes [ATTACH]68840[/ATTACH] Second picture shows inside the big pipe and the water flow direction [ATTACH]68843[/ATTACH]

Greetings I am attempting my first bathroom build, in my old farmhouse. I am concerned about any potential sewage problems. Here is what I have so far. Thank you for your time. [ATTACH]68851[/ATTACH]