Theo 1.0.0-rc2 · released 7 October 2026

Download Theo

The dynamic process simulator for municipal wastewater treatment plants: biology, chemistry and hydraulics in one model, on your own computer. Free to download and try — without a license, every session is a ten-minute demo with everything except saving.

Theo runs on Windows, macOS and Linux.

WindowsmacOSLinux

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Theo running the UCT with digester example: the flowsheet, a data table and a COD fate diagram
What's in the download

One installer, everything to start with

  • The Theo desktop application — the flowsheet editor, charts, tables and reports, with the simulation engine that runs on your own computer.
  • Seventeen example plants — complete plants to open, run and take apart, from an MLE and an oxidation ditch to a UCT-MBR and four SBRs on a fill queue riding out a storm.
  • The user manual — installed with Theo, readable offline.
  • A connection for AI assistants — an MCP server, so an assistant such as Claude can drive Theo, run your models and read every result.
Theo's Examples gallery: complete plants to open, run and take apart
From demo to license

Try it free, license it when you are ready

  1. Install and explore

    Without a license each session runs for ten minutes with everything except saving: build a plant, run it, chart the results, export a report. Restart Theo for another ten minutes.

  2. Get a license

    In Theo, open Help ▸ License… and copy your machine code. Buy a license online, or email the code to info@nonlineum.com and we send the license file back.

  3. Load it

    Click Load license file… in the same dialog. Theo unlocks at once; the plant you are working on stays open, ready to save.

Buy a licenseEmail us

Evaluating Theo for your organisation? Ask us for an evaluation license: it runs for a short, fixed period and needs no machine code.

The Theo License dialog in a demo session, with the time left and the machine code to send

All platforms

Theo 1.0.0-rc2, released 7 October 2026

Windows

  • Windows 10 or 11, 64-bit
  • An Intel or AMD processor with AVX2 (Intel from 2013, AMD from 2017 on)
  • Installs for you alone or for all users; networks can deploy the MSI with Group Policy or Intune
  • Signed by Nonlineum Labs Kft.
MSI installer

75.9 MB · Theo-1.0.0-rc2-installer.msi

SHA-256 checksume8fcd04a1a8a1fb3699a52981ef35bb93f261ba91cd4c1478738bafa2ca23d72

macOS

  • macOS 13 Ventura or later
  • Apple silicon (M1 or newer); Macs with an Intel processor are not supported
  • Open the disk image and drag Theo to Applications
Disk image

76.4 MB · Theo-1.0.0-rc2.dmg

SHA-256 checksum96e4f717f130741774ee65817ccccc7a733eb70eb81da9b4d7fa6d9848c78063

Linux

  • 64-bit, with glibc 2.39 or newer: Ubuntu 24.04 LTS, Debian 13, Fedora 40 or later
  • An Intel or AMD processor with AVX2
  • The AppImage runs without installing; the .deb installs with apt
AppImage

103.1 MB · Theo-1.0.0-rc2-x86_64.AppImage

SHA-256 checksum3343564a835009ac543d58acea7e95b1da3d11bcc9d389b747aa32811390d96c
.deb package

77.8 MB · theo_1.0.0~rc2_amd64.deb

SHA-256 checksumdf087820147bc201f12ddc7182edec30da3a4744afe694588719b5dd804ed3b9

To check a download, compare its checksum with the output of Get-FileHash in PowerShell or shasum -a 256 on macOS and Linux.

Older versions

Every Theo release stays available here, with its release date — to reproduce an earlier result, or to install the last version your license covers.

Version Released Windows macOS Linux Highlights
1.0.0-rc1 2 October 2026 71.3 MB 71.6 MB 98.3 MB 73.4 MB