MetSorb HMRG® outperforms competitive products in pilot study for reduction of arsenic from drinking water
Elevated concentrations of arsenic are found in many regions of the world. Naturally occurring arsenic in drinking water affects about 10% of the drinking water supplies in the United States, especially groundwater supplies. One of those supplies is located in Hopewell, New Jersey. Graver Technologies, in conjunction with researchers from Stevens Institute of Technology and scientists from the New Jersey Department of Environmental Protection, conducted a pilot test of the well water to demonstrate an efficient and economical way to reduce the arsenic levels.
Operating costs of the MetSorb® HMRG system are estimated to be substantially lower than for the other adsorptive media. These costs comprise mainly the periodic replacement of the media and the disposal of the spent media (typically adsorptive media for arsenic removal are not regenerable but rather a one time use). The use of the media is therefore optimized by running two adsorbers in series in a lead/lag mode, thereby allowing a greater utilization of the capacity of the MetSorb® HMRG. The spent MetSorb® HMRG media from the trial has been tested by the Toxicity Characteristic Leach Procedure, and has been determined to be nonhazardous waste.
The operating cost is also very dependent on the inlet levels of arsenic; as might be expected, lower operating costs are seen for an inlet of 15 ppb of arsenic than for 50 ppb. An expected range of treatment costs for HMRG is $0.10 to $0.50 per 1000 gallons of treated water, including disposal costs.
The Testing
Several adsorptive media (an iron based product), activated alumina, modified activated alumina, and MetSorb® HMRG were tested side by side on the Hopewell well water in identical test units. All were tested with an empty bed contact time of three minutes and the units were run beyond a breakthrough of arsenic in the effluent water of 10 ppb (the new federal standard for allowable arsenic in drinking water). No preconditioning of the water was done.
Test Results
Based on these tests, the treatment capacity decreased in the following order:
- MetSorb® HMRG
- Iron based media
- Modified activated alumina
- Activated alumina
The complete breakthrough curves are shown in the graph above as well, and clearly indicate the superiority of the HMRG in removing the arsenic.
Operating costs of the MetSorb® HMRG system are estimated to be substantially lower than for the other adsorptive media. These costs comprise mainly the periodic replacement of the media and the disposal of the spent media (typically adsorptive media for arsenic removal are not regenerable but rather a one time use). The use of the media is therefore optimized by running two adsorbers in series in a lead/lag mode, thereby allowing a greater utilization of the capacity of the MetSorb® HMRG. The spent MetSorb® HMRG media from the trial has been tested by the Toxicity Characteristic Leach Procedure, and has been determined to be nonhazardous waste.
The operating cost is also very dependent on the inlet levels of arsenic; as might be expected, lower operating costs are seen for an inlet of 15 ppb of arsenic than for 50 ppb. An expected range of treatment costs for HMRG is $0.10 to $0.50 per 1000 gallons of treated water, including disposal costs.
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