If taint spread is disabled, almost no way exists to actually get a taint biome. Taint biomes appear when fibrous tendrils appear and spread far enough. Without those spreading(which is what allows a taint biome to spread), no tainted biomes appear. So no matter how badly you muck up your infusion processes or how much you overflow your crucibles, the fibrous tendrils that spawn end up doing very little.
You end up with two options: Tainted Nodes(which are rare as all hell without the Node Modifier), or the Ecological Transmuter, from Technomancy, which can change wide swaths of land into either a magical forest, tainted land, or remove the effects of either of these biomes(thus turning them back to their old type if I understand correctly). Personally I suggest the latter, as it can both clean the land and taint it, both on a massive scale.
