Private wells in agricultural and rural areas frequently contain both iron and PFAS — a combination that complicates treatment design. Iron interferes with activated carbon and RO membrane performance, necessitating a carefully sequenced treatment approach that addresses iron before PFAS-specific treatment stages.
How Iron Affects PFAS Filtration
Dissolved ferrous iron oxidizes and precipitates as ferric hydroxide when it contacts oxygen or oxidizing agents, forming reddish-brown particles that rapidly clog filter media. In carbon systems, iron precipitation on carbon surfaces blocks adsorption sites available for PFAS. In RO systems, iron fouling on membranes reduces water flux and can permanently damage membrane polymers. Addressing iron before PFAS treatment is essential for system longevity and performance.
Iron Removal Technologies
Common iron removal approaches include air injection oxidation, greensand filtration, and oxidizing media such as manganese dioxide. Each converts dissolved iron to particulate form that can be filtered. After iron removal, a sediment filter captures residual particles before the PFAS treatment stage. This sequencing — iron removal, sediment filtration, then PFAS treatment — protects downstream components and maintains PFAS removal effectiveness.
Testing as the Starting Point
Well water quality varies enormously, and effective treatment design requires a comprehensive water analysis covering iron, manganese, hardness, pH, total dissolved solids, and PFAS. A water treatment professional familiar with well water systems in your region can specify an appropriately integrated system based on your specific analysis results rather than a generic approach that may underperform for your water chemistry.