That's an impressive improvement! So if I understand correctly, the UV light remains continuously active to prevent any growth? I noticed you mentioned the considerable cost of UV lamps. as you can see here https://karavaanhoney.com/the-best-honey-in-pakistan/

I think it will go down but you have a nice idea I will suggest you to carry on working on it and make it a successful project just like I am working on office removals website project you can see here.

Cool, btw, if the enviornment is tough, e.g. in a sewage well，can the solution be maintained for a long term, e.g. 2 or 3 years？

Cool project. You bring up biofouling in your github documentation; since turbidity measurement relies on transmission and absorption of light, it seems like this will introduce drift into your measurement. Do you plan on some sort of automatic calibration system? How will you control biofilm growth? Will the UV lights you mention in the brainstorming document get rid of drift?

Yeah, biofouling is the major issue with the system, without effective management the sensor lifetime will only be measured in days. Calibration is possible with sensors spaced at different distances (assuming every sensor gets equal growth) but the real key will be preventing growth with UV sterilization.

Here's an example from a commercial UV protected product after 2 months of exposure: 

https://images.oceannews.com/images/Feature/Figure-3.png

Wow, that's a crazy improvement! So the UV light pretty much stays on to inhibit any growth? You mentioned the high price of UV lamps; could you get away with relatively cheap LEDs?

That's the hope, but it all comes down to frequency. UVC LEDs like the ones used in that product are relatively new (I don't think its been on the market for a year yet) so we'll have to do testing to see how effective UVA & UVB LEDs will be.