Apparatus including a rigid fluid-permeable body, having a first non-planar fluid-permeable body surface, and having a second fluid-permeable body surface; a plurality of fluid-permeable cells in the fluid-permeable body; and a plurality of raised micro-scale features on the first fluid-permeable body surface. Apparatus including a fluid-permeable body having first and second fluid-permeable body surfaces; a plurality of fluid-permeable cells in the fluid-permeable body; a plurality of raised micro-scale features on the first fluid-permeable body surface; and a fluid containment body forming, together with the second fluid-permeable body surface, a second fluid containment structure. Methods, utilizing an apparatus, of treating a liquid with a fluid, and of maintaining a superhydrophobic surface.