Reddit mentions of BALDR Y Type High Precision Drip Irrigation Disc Filter-Male Pipe Threads 1 Pack (3/4 Inch)

Here is an old topic about PVC https://www.reddit.com/r/aeroponics/comments/8j1pyk/does_nobody_care_that_pvc_isnt_food_safe/

And that is the simplest disc filter https://www.amazon.com/BALDR-Style-Irrigation-Filter-Male-Threads/dp/B07CBTW465/ref=sr_1_10?ie=UTF8&qid=1527744612&sr=8-10&keywords=disc+filter

There are a lot of self-cleaning disc filters, in most cases they are designed for industrial use. Just search em in your region like "self cleaning disc filter"

https://azudusa.com/?portfolio=201-2

https://www.wateronline.com/doc/arkal-super-galaxy-self-cleaning-disc-filter-0001

https://www.exportersindia.com/hidry/self-cleaning-disc-filter-greece-889078.htm

UPD: I now understand your concern with PVC - ask the supplier for the relevant certificates.

I can speak now only for Russia, but here chemical properties of such simple polymers, as PVC, are studied in chemistry lessons at school. So it's obvious for everyone that PVC is safe. In the case of certification, this question is not even asked

About roots - a wrote at the beginning about filters, that you can use to clean water before pumping it. And Growing Medium zipgrow use is a foam, and, looks like, it is suitable for one, or a maximum of two grow cycles.