Precipitation Kinetics
Although precipitation processes are among the most common water and wastewater treatment techniques, fundamental concepts of these reactions in complex systems are not well known. A long-term objective of this project is to apply to wastewater precipitation processes the design and control strategies used in industrial precipitation. Sludge management can be made more efficient if precipitate is formed in consideration of final product characteristics.

Evaluation of Oxide Adsorbents for Water and Wastewater Treatment
In contrast with traditional precipitation processes, oxide adsorption processes can minimize or eliminate sludge production and simplify recovery of metals from waste streams. Composite adsorbents have been prepared using granular activated carbon as a support medium with either iron or manganese oxides deposited on the surface. Measured adsorption capacities indicate that these composite adsorbents make very efficient use of the small amount of oxide surface coatings. Furthermore, by lowering the solution pH, adsorbed metals can be recovered in a much more concentrated solution. The regenerated adsorbent can be reused in multiple processes.

Anderson, P.R.; Fan, H.J. (2005) “Copper and cadmium removal by Mn oxide-coated granular activated carbon” in Separation and Purification Technology Vol 45: 61–67.

Lee, S.; Anderson, P.R. (2005) “EXAFS study of Zn sorption mechanisms on hydrous ferric oxide over extended reaction time” J. Colloid Interface Science Vol. 286:82-89.

Lee, S.; Anderson, P.R.; Bunker, G.B.; Karanfil, C. (2004) “EXAFS study of Zn sorption mechanisms on montmorillonite” Environ. Sci. Technol. Vol. 38, No. 20:5426-5432.

Anderson, P.R. and L. Axe, "Sr Diffusion and Reaction Within Fe Oxides: Evaluation of the Rate Limiting Mechanism for Sorption," J. Colloid and Interface Sci., 175: 157-165 (1995).

Anderson, P.R., D. Marani, and J.W. Patterson, "Alkaline Precipitation and Aging of Cu(II) in the Presence of Sulfate," Wat. Res., 29(5): 1317-1326 (1995).

Anderson, P.R., M. Su and D.K. Cha, "Influence of Selector Technology on Heavy Metal Removal by Activated Sludge: Secondary Effects of Selector Technology," Wat. Res., 29(3): 971-976 (1995).

Anderson, P.R.,V. Gounaris and T.M. Holsen, "Characteristics and Environmental Significance of Colloids in Landfill Leachate" Environ. Sci. Technol., 27(7): 1381-1387 (1993).

Anderson, P.R., B. Luo, and J.W. Patterson, "Kinetics of Cadmium Hydroxide Precipitation," Wat. Res., 26(6): 745-751 (1992).

Anderson, P.R., T.M. Holsen, E. Taylor, et al., "Removal of Sparingly Soluble Organic Chemicals from Aqueous Solutions with Surfactant-Coated Ferrihydrite," Environ. Sci. Technol., 25: 1585-1589 (1991).

Anderson, P.R., W. Chen and T.M. Holsen, "Recovery and Recycle of Metals from Wastewater with a Magnetite-Based Adsorption Process, Res. J.Wat. Pol.Cont. Fed., 63(7): 958-964 (1991).