Hi. I have a bath with a tiled roman tub next to my shower that is approx. 48" across and has no overflow. I'm on a septic system. This drain is the lowest in the house and closest to the tank. I would like to get rid of it by capping the drain and filling it in then tiling over it. The drain body looks like just a flange with a coverplate that screws to the top of the flange. Wondering if anyone has seen this setup before and has any suggestions on how to cap it off. Pics attached. Thanks.