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As U.S. Environmental Protection Agency radium regulations tightened, some cities found themselves above the allowed limits. The city of Mason, Mich., had levels that fluctuated from below to just slightly above the limit. Since radium was an issue that had never been dealt with by Mason officials, they sent out a public inquiry for the best system for radium removal. Seven teams presented their ideas and bid on the project.
Layne Christensen Co. was asked to join the Wolverine Engineering team to present options on the radium removal treatments. Layne presented approximately six techniques and determined that hydrous manganese oxide (HMO) was the most effective for radium removal with the added benefit of iron removal (iron was found at higher levels in at least two of the city’s four wells). Layne conducted pilot tests at Mason’s Ash Street Well. It was determined that the HMO system was the most suitable and cost-efficient option available. Since there were four wells, an engineering evaluation determined that treating at one central location was preferable to treating at each well facility separately.
In addition to the four existing wells, a fifth well was drilled at the time of the treatment plant installation. All wells were piped to a central location where Layne installed eight 6-ft-diameter vessels for radium removal using HMO with LayneOx catalytic media. The system’s combined operating capacity is 2.5 million gal per day. The Layne Bridgewater plant fabricated the skid and controls. Layne also provided extensive technical support for startup and program debugging.
Installation and Results
The LayneOx treatment system for radium removal utilizes the HMO process to help adsorb and co–precipitate radium from water. With the installation of the eight smaller vessels instead of one large vessel, a high loading rate was achieved and the redundancy built into this system allows for greater flexibility. One vessel could be down for maintenance without taking the whole system offline, keeping the system operable while saving time and money. The system uses a fully automated backwash system for minimal operator oversight.
The HMO system also has lower chemical costs compared to other radium treatment technologies such as softening systems, which consume salt; and the long-term maintenance cost is lower as well. HMO also removes iron without any additional processes, which provides better quality water with no extra time or cost.
The LayneOx treatment vessels were provided as two four-vessel skids, which were pre-piped and wired for reduced installation cost. The system uses Catalytic Filtration Media for Higher Loading Rates [6 to 12 gal per minute (gpm)/sq ft vs. Greensand at 3 gpm/sq ft]. At the design flow rate, the system is operated at a loading rate of 6.25 gpm/sq ft.
The radium removal system has been online and performing well since September 2008.
In 2010, Wolverine Engineering won a Project of the Year award for the treatment plant from the American Public Works Assn.
David Osgood is marketing manager for Layne Christensen Co. Osgood can be reached at [email protected] or 262.246.4646