Since 3D printed are out, I beleive in one thing combinating Structured Carbon layers with differents filters in one straw. Everything design as an open kit with differents carbon layers that can be fill and clean with carbon. You aspirate, water passthrought big layers that evolve to tiny layers then water reach you and you can drink in one move.
Then density of carbone stack structure can be enought to clean. You can add or remove layers to change use.
Main material is everywhere, straw need bio-materials.
You can also create structured 3d carbon box/bubble that can fit to existing straw or other thing , this bubble can have big porus outside with road to the inside that shrink at the end. I hope it can be done.