I downloaded it just today and I love the simplicity of it but my landfill recipe seems to have vanished. I downloaded the mod after I had already researched landfill and I still have some landfill available to me in chests and stuff. I would have gone back to a previous save but I didn't notice this before the autosave overwrote the previous saves without the mod. I've tried Turning it off and finally deleting it but my recipe is still not there though the research still is

you have to research the tech to unlock it, landfill is a different tech

yes but the research still says it's already been completed

just reread you message and this is waterfill and has nothing to do with landfill. landfill is a game default thing.
if you cant make waterfill then take a screenshot and show me your completed research and your crafting menu on the first tab (logistics) also a save file would allow me to check too