A 2-p brochure from USFilter, Schaumberg, IL, discusses the ARRT Acid Recovery and Recycling System, which recovers nitric, hydrochloric, hydrofluoric, fluoboric, and sulfuric acid and acid mixtures from concentrated baths that usually must be discarded. The system uses an advanced membrane separation technology, known as diffusion dialysis, designed for the metal finishing industry to avoid dumping concentrated acid baths.