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Filter Straw

The 3-stage water filter straw is designed to purify contaminated water in rural or emergency settings. It consists of three filtration stages:

  1. Open-pore sponge to trap solid particles.

  2. Activated charcoal to remove chemical impurities.

  3. Iodine crystals to kill bacteria, viruses, and pathogens

The straw is coated with a waterproof sealant to address the porosity of FDM 3D prints, ensuring water-tightness and preventing leaks.

This project introduced me to multi-stage water filtration, practical applications of chemical purification, and post-processing techniques for 3D prints.

Step-by-Step Working

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  1. Filtration Stages:

    • Stage 1: Pre-filtration (Solid removal)

      • The first stage consists of a coarse-pore sponge that blocks large solid impurities like dirt, sand, and debris.
         

    • Stage 2: Chemical Filtration (Activated Charcoal)

      • The second stage contains activated charcoal, which absorbs chemical contaminants, including chlorine, pesticides, and organic compounds.
         

    • Stage 3: Pathogen Elimination (Iodine crystals)

      • The final stage holds pure iodine crystals, which dissolve in the water, killing bacteria, viruses, and parasites.

  2. 3D Printing and Assembly:

    • The straw was 3D-printed in two halves and later assembled.

    • The seams were sealed with a waterproof coating to prevent leaks caused by the inherent porosity of FDM prints.

  3. Usage:

    • The user simply places the straw in contaminated water and sips through the mouthpiece.

As the water passes through each stage, it is progressively purified.

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