Testing Metallic Iron Filtration Systems for Decentralized Water Treatment at Pilot Scale

There are many factors to consider for the design of appropriate water treatment systems including: cost, the concentration and type of biological and/or chemical contamination, concentration limits at which contaminant(s) are required to be removed, required flow rate, level of local expertise for on-going maintenance, and social acceptance. An ideal technology should be effective at producing clean, potable water; however it must also be low-cost, low-energy (ideally energy-free) and require low-maintenance. The use of packed beds containing metallic iron (Fe-0 filters) has the potential to become a cheap widespread technology for both safe drinking water provision and wastewater treatment. Fe-0 filters have been intensively investigated over the past two decades, however, sound design criteria are still lacking. This article presents an overview of the design of Fe-0 filters for decentralized water treatment particularly in the developing world. A design for safe drinking water to a community of 100 people is also discussed as starting module. It is suggested that Fe-0 filters have the potential for significant worldwide applicability, but particularly in the developing world. The appropriate design of Fe-0 filters, however, is site-specific and dependent upon the availability of local expertise/materials.