Inquiry (采购产品): Sand Filter I am an environmental consultant currently working on a project in eastern KY. We are operating a pump and treat system to remediate groundwater of gasoline which was relaease at the site several years ago. The treatment system consists of the following: - Groundwater passes through an oil water separator, where it is then run through an air stripper; - From the air stripper it is run through 3 X air sparge tanks; - After the air sparging tanks, the water is pumped through 2 X 55 gallon activated carbon canisters; - From the carbon units, the water is discharged into a nearby creek. The system currently pumps an average of 5-7 GPM 24/7. It is anticipated that the system will need to run for at least another year and quite possibly 10 years. The State NPDES permit requires bi-monthly discharge sampling be conducted on the effluent before entering the creek. All gasoline related constituents are below the States maximum allowable limits for discharge water. However, we have had exceedences for total suspended solids (TSS). The elevated concentrations of TSS in the discharge water is directly due to precipitated iron. Water comes out of the ground clear, but during the air sparging process, the water turns extremely turbid, dark rusty brown in color. The carbon canisters filter out the iron precipitate for several weeks before becomming clogged resulting in elevated TSS numbers. We have replaced the carbon and have started back flushing the carbon filters, which work for a while, only to have the same thing happen again. Continuous replacement of the carbon and back flushing is not a cost effective way to treat this problem. We need to come up with a pre- filtering system, taking into account the initial costs of component installation and the yearly costs for O&M. We have thought about using a sand filter before the carbon units and then backflushing the sand filter routinely into a large settling tank. The top water in the settling tank would then have to be pumped off and run through the carbon filters to make room for more back flush water. This would require a lot of costly O&M. One of our service technicians thought about adding an iron precipitant chemical before the sand filter. Please respond with any suggestions or thoughts you might have on this matter. **** Hidden Message ***** John Lydzinski PO Box 848 Bluefield Industrial Park Bluefield, VA 24605 USA Company: Marshall Miller & Associates Title: Project Manager Phone: 276-322-5467 Fax: 276-322-1510 E-mail: john.lydzinski@mma1.com **** Hidden Message ***** john.lydzinski@mma1.com
