I would start by checking the pH of the chemicals they are using (including the water conditionong process). RO water may have a lower pH in the permeate or if they are using DI water that some of the regenerate chemicals are bleeding through.

grrun

Have them use a caustic blend as part of their cleaning solution or as Tom mentioned use caustic afterwards as elementary neutralization is rcra exempt.  

I would do a first rinse to the OWS with no cleaning agents and then route the wash water with the cleaning solution to bypass the OWS so it doesn't emulsify anything in the OWS.

Rather than raising pH, you should try to change the chemicals used. If appropriate chemicals used in proper quantity, then I am sure problem of your friend will be sorted out easily.