A Midwest biotechnology facility utilizes groundwater for process and cooling water to produce animal feed supplements and industrial amino acids. Iron and manganese concentrations in the natural groundwater interfered with process and cooling water uses and lead to excessive maintenance costs. In 1985, a Vyredox method in situ treatment plant was installed to reduce iron and manganese concentrations in three 1,200 gallon per minute (gpm) groundwater supply wells. Vyredox uses a batch method to recharge oxygenated groundwater around a production well to facilitate the in situ biochemical transformation of iron and manganese from the soluble to the insoluble phases. The process causes these metals to be precipitated out of solution prior to reaching the production well. The Vyregard method relies on similar in situ processes but continuously recirculates aerated groundwater in the aquifer. In the proper hydrogeologic setting, these methods provide cost-effective alternatives to conventional ex situ iron and manganese treatment. Includes 5 references, tables, figure.