Theia Takes on Iron Using an Air Stripper
Location: Rhode Island
Air stripping is an effective and efficient groundwater technology. However the presence of iron in most groundwater formations in the northeastern US as well as many other regions in the US can make these systems difficult to operate. Fortunately there is a better solution.
Challenge: A customer is operating a groundwater treatment system in Rhode Island. In addition to chlorinated solvents the groundwater contains very high levels of iron (30- 50 mg/l) as well as lower but still unacceptable levels of arsenic. The existing tray air stripper was not able to handle the iron and needed to be disassembled and pressure washed every 2-3 weeks. As part of a new permit, the system not only had to deal with the iron but the customer was required to remove both the iron and arsenic.
Solution: Theia Air proposed the use of our innovative air stripping process that cannot clog or foul. Not only does this unique design not need any protection but it is actually part of the iron removal and metals treatment process. The system will directly oxidize any iron in the groundwater rendering it insoluble while also elevating the dissolved oxygen sufficiently to eliminate the need for a chemical oxidant when iron filters are being used. Because of the exceptionally high turbulence, additional metals treatment chemicals can be introduced if the target metals need treatment beyond oxidation.
Understandably, this all sounded a little too good to be true, and the state and the customer required a demonstration. This test had to be conducted quickly and could only last one day due to the constraints of the site and the weather. Theia Air quickly assembled a trailer mounted system from available equipment and brought it to the site for the demonstration.
Results: the vast majority of the VOC’s were removed as required. The system fully oxidized all the iron in the groundwater rendering is fully insoluble and had Dissolved Oxygen to spare. As can be seen from the pictures and video, the water coming in appears crystal clear but quickly turns red and then brown as it passes through the air stripper. The water in the discharge sump is not only full of oxidized iron but has a DO reading of 8.5. This design allows for the removal of very high iron loading without ANY chemicals.
