AWWA WQTC55068

Preliminary work has demonstrated that arsenate removal by granular ferric hydroxide (GFH) material is less sensitive to competition from common water quality constituents than activated alumina. GFH particle size affected pseudo-equilibrium results, but sufficient time for intraparticle diffusion may not have been provided with the large size material. As received GFH material has a wide range of particle sizes. Pilot and rapid small scale column test (RSSCT) operation demonstrated limited ability to compare results, although operation of GFH media in on-off cycles improved overall arsenate removal. A conceptual approach paralleling that developed for natural organic matter (NOM) removal by granular activated carbon (GAC) may be applicable for inorganic ion removal (e.g., arsenate) by porous sorbents (e.g., GFH). However, such scaling approaches must go back to the fundamental principles that we used to (GAC) scaling equations for organic macromolecules, and verify their applicability for smaller inorganic ions. Includes tables, figures.