I am looking for procuring AQUASIM software to carry out ADM1 modelling of anaerobic digesters. But I could not find any appropriate source for procuring the software. What are the other possible options (alternative software) preferably open source that could be availed to carry out the ADM1 model?
ADM1 is basing on ordinary differential equations (ODEs) and can be carried out by any software which will provide solvers for ODEs systems. You can run it in Python, Matlab, even C++ or C#, however the last two options are significantly slower than the rest. Some time ago I've written an article in this topic, If you are interested:
Article A comprehensive comparison of ODE solvers for biochemical problems
However keep in mind, that doing this requires much more knowledge and experience, than just running it in Aquasim. This software is very simple, you can just load the file, and change few variables and that's it - some don't even need to understand what ODE is. If you decide to port this model to one of mentioned environments (Pythons is a good start point I think), you need to rewrite everything manually. Aquasim is relatively uncommon platform, I doubt you can find any tool to convert it to Python for example. And this would require much deeper understanding of the process and model data flow. A special focus need to be put on pH aspect, as the Aquasim does not clearly shows how it is calculated - you would possibly need to figure out your own way to solve it.
The other free alternatives are
* Matlab, and get the ADM1 files - there was a question posted on ResearchGate as to the location of those files. The original files ran under Matlab 7. Updated files are available under GitHub.
* OpenModelica, using the wastewater library. You need the updated version which adds ADM1.
* STOAT, which I work on. The ADM1 implementation was influenced by the Lund University 'standard benchmark' version, i.e. the Matlab files described in the 1st bullet point.
I have not tried the OpenModelica version, as I have not got to grips with Modelica.
Tutorial is shared here in this link
https://www.eawag.ch/fileadmin/Domain1/Abteilungen/siam/software/aquasim/reichert_1998_aquasim_tutorial.pdf