Color Removal from Groundwater By Ion Exchange and Sludge Recycle Techniques

摘要

Several towns in Mississippi and in the southeastern United States are plagued with groundwater which exceeds the secondary maximum contaminant level of 15 color units, set by the United States Environmental Protection Agency. The primary objective of this study was to investigate two treatment techniques for removing the organic color from a groundwater. Ion exchange was the first treatment technique which was investigated. Eight different resins were tested in batch studies, and two pilot plant studies were conducted at a well site. Both the batch study, and the pilot plant studies indicated that IRA-904, a Rohm and Haas strong base styrene-divinylbenzene anion resin, performed the best. A batch study, which was conducted to determine the best regenerate, indicated that a 10 percent solution of 5 parts NaCl to 1 part NaOH was the best regenerate for resin, IRA-904. In the second pilot study the regenerate solutions were used twice, and it appeared that the resins were satisfactorily regenerated with the used regenerate solutions. Resin, IRA-904, was regenerated seven times, and a loss in capacity was experienced with each regeneration. In the coagulation study ferrous sulfate, ferric sulfate, and alum were administered along with chlorine, lime, and starch in several standard jar tests. The results indicated that alum, when used alone, performed best as far as color removal, but dosages of 250 mg/l to 300 mg/l were required to remove all the color from the raw water. When the alum sludge was recycled, it was discovered that a 10 percent by volume recycle of sludge along with an additional 10 mg/l of new alum could remove all the color from the raw water.