There are threads regarding WTA in the E-Liquids forum. That would be my recommendation as where to start looking for information. It's a rather niche product and not likely something very many new members are familiar with. You can also visit the Aroma E-
juice thread in the suppliers forum, they sell WTA products.
ETA: Just to clarify, WTA isn't added to juice. Simply put, the process refers to
not removing some of the naturally occurring alkaloids when extracting nicotine.