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Iron coagulation and direct microfiltration to remove arsenic from groundwater
Author(s) -
Ghurye Ganesh,
Clifford Dennis,
Tripp Anthony
Publication year - 2004
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 - 10.1002/j.1551-8833.2004.tb10605.x
Subject(s) - microfiltration , chemistry , arsenic , flocculation , leaching (pedology) , ferric , hydroxide , fouling , ferrous , membrane fouling , coagulation , sulfuric acid , nuclear chemistry , environmental chemistry , membrane , inorganic chemistry , environmental science , soil water , biochemistry , organic chemistry , psychiatry , psychology , soil science
Arsenic (As) removal using ferric hydroxide coagulation followed by direct microfiltration without flocculation was investigated for an application in Albuquerque, N.M. Typically, the influent drinking water (unchlorinated) was contacted with ferric hydroxide for ≤20 s in a rapid mixer and passed through a membrane microfiltration unit with a nominal pore size of 0.2 μm. Variables investigated included pH, iron (Fe) dose, mixing time and energy, filtrate flux, and backwash interval. The pH and ferric dose were found to be the most important variables controlling As removal. As removal to low levels (<2 μg/L) was achieved using either a dose of 7 mg/L Fe without deliberate pH reduction or a smaller dose of 1.9 mg/L Fe after sulfuric acid addition to reduce pH to 6.4. Extended operation (three to five days) showed that consistent As removal was obtained without any membrane fouling. Both the backwash water and the dried sludge passed the toxicity characteristic leaching procedure test as a nonhazardous waste.