ekolog16
Civil/Environmental
- Feb 5, 2010
- 17
I'm supporting a groundwater treatment system that has problematic fouling. It's about a 10 gpm system from a french drain that pumps shallow groundwater through bag filters and then two 500-lb activated carbon filters to remove BTEX (~1 ppm total). It's to prevent contamination to a small river where the treated water discharges to. The pump and treat system is mandated but in-situ remediation is forth coming of the plume.
The pumps, piping, and bag filters are subject to fouling and require frequent cleaning. Iron levels are around 8 mg/L entering the building, mostly dissolved. We measured ferrous iron at about 5 ppm. I suspect most of the oxidized iron is from the ferrous iron mixing with air in the french drain and sump. Calcium and magnesium hardness is also high (250 mg/L as CaCO3) but pH is around 7.1. Manganese is around 0.4 mg/L.
We're considering dosing a sequestering agent (polyphosphate) for iron control and peroxide for biofouling into the sump. I don't have much experience with iron sequestration and am concerned it won't be entirely effective or may increase the activated carbon frequency. Does anyone have success using a sequestering agent before activated carbon?
It's a remote site in a small building with no sewer discharge (nearest sewer is 5 miles away). Installation of aeration and sedimentation or sand filter are the other options being considered but require significant construction (site is in lower Midwest). Are there any other options I should be considering?
Thanks,
Ekolog
The pumps, piping, and bag filters are subject to fouling and require frequent cleaning. Iron levels are around 8 mg/L entering the building, mostly dissolved. We measured ferrous iron at about 5 ppm. I suspect most of the oxidized iron is from the ferrous iron mixing with air in the french drain and sump. Calcium and magnesium hardness is also high (250 mg/L as CaCO3) but pH is around 7.1. Manganese is around 0.4 mg/L.
We're considering dosing a sequestering agent (polyphosphate) for iron control and peroxide for biofouling into the sump. I don't have much experience with iron sequestration and am concerned it won't be entirely effective or may increase the activated carbon frequency. Does anyone have success using a sequestering agent before activated carbon?
It's a remote site in a small building with no sewer discharge (nearest sewer is 5 miles away). Installation of aeration and sedimentation or sand filter are the other options being considered but require significant construction (site is in lower Midwest). Are there any other options I should be considering?
Thanks,
Ekolog