AWWA ACE65173

The objective of this study was to investigate the ability of polypropylene fibers to retain a high iron-oxide coating under reasonable washing flow rates during media development through column studies. High surface area polypropylene fibers were coated with iron-oxide. In column studies, iron-oxide coated polypropylene geosynthetic fibers were tested under hydraulic flow conditions to evaluate the ability of the fibers to retain the coating. Experiments were also conducted to determine its ability to be regenerated physically. The polypropylene mat achieved an iron density of up to 100 mg Fe/g of material and retained 72% of this coating after being subjected to hydraulic flows several times the reasonable rate. However, even after washing at 100 bed volumes, the suspended iron concentration of the effluent water periodically exceeded the secondary maximum contaminant level (MCL) for iron in drinking water by a small amount. Further investigation should include systematic exploration of the factors which influence iron retention and consideration of more polar fibers which may bond more tightly to the iron oxide, minimizing iron loss in effluent water. Includes 9 references, figures.