Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Ultrafiltration:

"

:*Capable of exceeding regulatory standards of water quality, achieving 90–100% pathogen removal [3] UF processes are currently limited by the high cost incurred due to membrane fouling and replacement.[4] Additional pretreatment of feed water is required to prevent excessive damage to the membrane units.