3DPLAM

• Moreno Gabriel 0009-0008-8260-2625 (ETH Zürich, Global Health Engineering) design, construction, testing, writing
• Jakub Tkaczuk 0000-0001-7997-9423 (ETH Zürich, Global Health Engineering) supervision, page development & maintenance
• Caetano Dorea 0000-0001-9367-0668 (University of Victoria) supervision
• Elizabeth Tilley 0000-0002-2095-9724 (ETH Zürich, Global Health Engineering) supervision

Open-source, 3D-printable membrane-filtration manifold for Escherichia coli quantification in drinking water. Three printed parts (base, funnel and filter support, all printable without support structures on any FDM printer) test 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 the 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, at a comparatively high price.

Full site, with photos, renders and the print-settings requirement are available here.

At a glance

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

Quick start

1. Read hardware/README.md for the parts table, envelopes, and the choice between the two filter-support and two funnel variants.
2. 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 read hardware/print-profiles/README.md for the any-slicer equivalents.
3. Print stl/base.stl, stl/funnel.stl and stl/filter-support-strand-mesh.stl (the default, validated filter support) as separate jobs.
4. Assemble and operate the manifold following docs/assembly.md and docs/operation.md.

When printing in recycled PET instead of ABS, use the geometry in hardware/rpet/, not hardware/stl/ and see docs/rpet.md.

Repository layout

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 in Onshape, copy it and edit your own

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
├── 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

Citation

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. Version 1.0.0. https://doi.org/10.5281/zenodo.22025813

License

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.