Regeneration and Reuse of Aqueous and Semi-Aqueous Wash Media: Dissolved Organics, Suspended Solids and Process Control

Version 0.2 supersedes ER-273 v0.1 dated 23 September 2026 and corrects citation linkage and reference identity without changing the scientific argument. Aqueous and semi-aqueous post-processing can reduce reliance on volatile organic wash solvents, but the spent wash medium becomes a formulation-dependent process stream containing dissolved, dispersed and suspended material. Water-washable does not mean contaminant-free, and optical clarity does not establish chemical cleanliness [3]. Direct published evidence shows that water and detergent can remove residual material from a specific water-washable dental photoresin and that washing conditions affect final-part properties [1]; however, this is evidence about part washing, not about repeated reuse of an increasingly loaded wash bath. The controlled corpus also establishes that wash-water disposition and waste classification remain separate questions owned by ER-178. ER-273 therefore defines a qualification architecture for regeneration and reuse: establish the incoming stream, separate dissolved from suspended loading, measure removal and carry-over, track bleed and make-up, verify cleaning performance on representative parts, and stop reuse when any non-compensatory gate fails. No universal filtration rating, carbon dose, UV treatment, conductivity limit, turbidity limit or reuse-cycle count is prescribed.

ER-273 · Version v0.2.