Sali TDDeltapark,
I had the same problem at work. I then changed to stainless steel handles. You can order them through Amazone.
BTSKY® new brushed 304 stainless steel wine beer tap swivel drink dispenser (16mm)
They fit perfectly and have lasted for 2 years without any problems.
Can be used for kombucha without any problems. I bought the same vessel for the same purpose and used it successfully. Just don't close the lid completely during the process ... ;)