Re: ultraviolet light (edited)

This is one way to disinfect swimming pools and spas. It's a bit expensive; but better than chlorine. I use to have a countertop water purifier, attached to my faucet, that had an UV bulb in it as well as a charcoal block. I think that the water has to touch the bulb to be disinfected.

I also have an air purifier that has an UV bulb in it.

UV is supposed to kill all parasites.

Ozone is another good parasite killer. I have a fairly cheap ozonater that I put in the sink or bowl of water where I also have new produce from the grocery store. I keep it in for about 5 minutes. Makes me feel that I'm cleaning the veggies.