- Moreno Gabriel
0009-0008-8260-2625 - ETH Zürich, Global Health Engineering — design, construction, testing, writing
- Jakub Tkaczuk
- Caetano Dorea
- Elizabeth Tilley
0009-0008-8260-2625Open-source, 3D-printable membrane-filtration manifold for Escherichia coli quantification in drinking water. Three printed parts: base, funnel, filter support, printable without support structures on any FDM printer allow for testing drinking water with a syringe and a membrane filter. Validated against a Millipore EZ-Fit™ stainless-steel manifold as the reference instrument for the household drinking-water testing used in WHO/UNICEF water-quality surveys. 3DPLAM does not replace Millipore EZ-Fit™; its contribution is that the design is open and can be printed locally at low cost, whereas the reference instrument can only be bought for comparatively high price.
Full site, with photos, renders and the print-settings requirement are available here.
| Characteristic | Description |
|---|---|
| Parts | Base + funnel + filter support (2 concurrent alternatives), no supports |
| Material cost | ≈ $0.80 per set (ABS) |
| Mass | ≈ 32 g |
| Print time | ≈ 100 min |
| Reference instrument | Millipore EZ-Fit™ stainless-steel manifold (≈ $2,460) |
| Validation | 8 sites × 3 manifolds × 3 replicates = 72 filtrations, 16 printed-vs-reference comparisons |
| Headline result | 15 of 16 classifications accepted within the 5% WHO boundary-tolerance rule; 12 of 16 match exactly with no tolerance applied |
| Sustainable route | Funnel and filter support printable in rPET from recycled bottles |
- Read
hardware/README.mdfor the parts table, envelopes, and the choice between the two filter-support and two funnel variants. - A manifold sliced at default settings is porous: the syringe draws air through the walls instead of pulling water through the membrane, and filtration fails. Import the profile for your printer from
hardware/print-profiles/and readhardware/print-profiles/README.mdfor the any-slicer equivalents. - Print
stl/base.stl,stl/funnel.stlandstl/filter-support-strand-mesh.stl(the default, validated filter support) as separate jobs. - Assemble and operate the manifold following
docs/assembly.mdanddocs/operation.md.
When printing in recycled PET instead of ABS, use the geometry in hardware/rpet/, not hardware/stl/ and see docs/rpet.md.
hardware/ CERN-OHL-S v2 — the parts to print
├── README.md Parts table, envelopes, variant choices
├── stl/ Printable meshes (millimetres)
├── step/ Editable B-rep — modify the design here
├── rpet/ Shrinkage-compensated geometry for recycled PET
├── assembly/ Reference assembly (not a printable part)
├── print-profiles/ Slicer settings for a gas-tight print
└── onshape.md Source CAD, by version
docs/ CC BY 4.0 — how to print, build, run and interpret it
├── printing.md Print settings, orientation, materials matrix
├── assembly.md Putting the three parts together
├── operation.md The E. coli filtration protocol, verbatim
├── validation.md What was tested and the headline result
├── rpet.md Bottle-to-filament, with upstream credit
├── design-history.md Version history predating this repository
└── thesis.pdf The BSc thesis this release is drawn from
data/ CC BY 4.0 — the tidied functional and material test data
tools/ Scripts that regenerate every figure and gate CI
site/ This repository's GitHub Pages site (Astro)
CITATION.cff Machine-readable citation metadata
If you use this hardware, please cite it — see CITATION.cff for the machine-readable record:
3DPLAM — 3D-Printed Lightweight Affordable Manifold for Microbial Water Quality Testing. Moreno Gabriel, Jakub Tkaczuk, Caetano Dorea, Elizabeth Tilley. ETH Zürich, Global Health Engineering. https://github.com/Global-Health-Engineering/3dplam
Different parts of this repository are released under different licenses, following standard practice for open-hardware projects:
| Component | License |
|---|---|
Hardware design (CAD, STL, STEP in hardware/) |
CERN-OHL-S v2 |
Documentation (docs/, this README) |
CC BY 4.0 |
Datasets (data/) |
CC BY 4.0 |
Site and tooling (site/, tools/) |
CC BY 4.0 |
The rPET route in hardware/rpet/ and docs/rpet.md rebuilds Petamentor2, an open-source PET-bottle-to-filament machine designed by Ondřej Šraitr (https://petamentor2.com/) — credited, not redistributed; build your own from the upstream project.