Hello! I'm currently working on my bachelor's thesis which is a water quality monitoring system using Arduino sensors. My main focus is bacterial pathogens. My question is what are the sensors that is capable in detecting contaminating bacteria in a water, may it be one sensor or many. Thanks in advance!
You're skirting the bounds of double posting here - your existing thread is much the same question.
I suspect you'll be lucky to get much help here with identifying sensors - it's a bit too specialized and looks like a rather expensive proposition for hobbyist folks to have worked with. Your thesis advisor would hopefully be a better resource.
If you can find an appropriate sensor that can talk to an Arduino in some way, you can expect plenty of help with your code if you struggle with interfacing it though.
Try searching Amazon for this: "Portable ATP Hygiene Monitoring System Hygiene Moniter Meter Bacteria Analyzer Tester ATP Fluorescence Rapid Detector". Pricey, and likely not what you're really looking for, but, as I expect google has told you, such things don't seem to be common.
Whenever you see an obvious application like this, I want you to realize that the reason you don't have them out yet is NOT because nobody else has thought to attach some common sensor to an Arduino and invent one. You're never going to be the inventor that way.
I mean, if such a sensor really exists, do you really think you're the first person to think that it might be used to test water quality? And if it really is so obscure that you might be the first to think of it, would one of us know about it? I mean I promise, if I already knew of such a sensor then I would have already designed the device and be retired as a billionaire.
The reason something like this doesn't exist is almost always going to be because the sensor doesn't exist. We get tons of great ideas for products in posts on these forums, if only such a sesor for this thing or that thing exists.
Just remember, lots of people know how to use an Arduino. If there is some obvious application with some existing sensor then it will have been done. You either need to find an application that isn't so obvious or get started trying to invent a sensor. Just be aware that whole teams of hundreds of engineers with lots of money and resources have already been trying. So be sure to keep your expectations realistic.
Now if you're at a good University with good resources I can give you some ideas on bacterial detection, but they're not going to involve Arduino.
You can try using flow cytometry and try to find some way to specifically label the bacteria you want to see. Custom antibodies come to mind but that's hard to develop. Genomic methods like FISH (look it up) might be easier to develop but are harder to actually perform.
If someone has a mass spec with a MALDI front end you could see if there is any way to molecularly fingerprint the bugs you're looking for. That's going to take a LOT of data and a LOT of computing power but I know for a fact that it can be done.
It all depends on what sort of degree you're going for and what sorts of things you want to learn.