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Pilot Testing Strong Base Anion Exchange for CrVI Removal
Author(s) -
Gorman Craig,
Seidel Chad,
Henrie Tarrah,
Huang Lifei,
Thompson Robert
Publication year - 2016
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.5942/jawwa.2016.108.0028
Subject(s) - hexavalent chromium , nitrate , ion exchange , ion exchange resin , chromium , sulfate , chemistry , base (topology) , water treatment , raw water , environmental chemistry , environmental engineering , waste management , pulp and paper industry , environmental science , ion , inorganic chemistry , engineering , mathematics , organic chemistry , mathematical analysis
California, the first state in the nation to regulate hexavalent chromium (CrVI) in drinking water, has set a maximum contaminant level (MCL) of 10 µg/L. To comply with the MCL, a California utility conducted extensive pilot studies to determine the best‐performing ion exchange resin, empty bed contact time (EBCT), and hydraulic loading rate (HLR). The CrVI removal capacities of four strong base anion exchange resins were tested at seven wells. Results showed that between 12,000 and 37,000 bed volumes of treatment can be expected before an 8‐µg/L breakthrough threshold. HLR was shown to have little effect on CrVI removal within the range tested (7.5 to 30 gpm/ft 2 ), whereas longer EBCTs (>45 s) appeared to improve performance. The presence of co‐occurring anions in the raw water—namely, sulfate and nitrate—had substantial effect on the resin's chromium loading capacity.