One of the things I always get asked when customers see my display kitchen with the under sink drawers is “How does the waste work?” It’s something I always explain as requiring the back mounted waste kit by Oliveri, or “Opti-Space Connector Kit”
This allows for the waste pipe to be mounted flat at the very back of the cabinet, which in turn means that a drawer can be installed into the cabinet. The drawer will need to be around 100mm shorter in depth than usual due to the waste still be required.
Also if you’re floor waste comes up in the middle to front of the cabinet, it should ideally be returned under the kick board with two ninety degree bends so that it can be brought up at the back of the cabinet as well.
This can also be achieved by using a double bowl connector, then fitting a ninety degree bend pointing towards the back of the cabinet, then another ninety degree bend pointing downwards being joined into the normal s trap as per normal.