Abstract
Removals of dissolved organic carbon (DOC), ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) and carboxylated alkylphenol polyethoxylate metabolites (APECs) were studied at the Sweetwater (Tucson, Ariz.) soil aquifer treatment site that treated chlorinated secondary effluent. The site was operated in a first phase by flooding irregularly for weeks interrupted by days of drying and in a second phase by a regular schedule of flooding for 3 days and drying for 4 days. The average hydraulic loading rates were 0.13 and 0.17m/day in the first and second phases, respectively. During drying, oxygen intruded at least 3m deep into the unsaturated subsurface causing nitrification of the ammonium that was retained in the top layer during flooding. Nitrification increased nitrate concentrations to >200mg/L but most was removed to <10mg/L during transport to 38m depth. At 38m depth, removals of DOC, EDTA, NTA, and APECs during the first phase were 85, 80, 90, and 98%, slightly higher (<7%) than during the second phase. Most of the DOC removal occurred during transport to 3m and most of the trace organics removal occurred during transport from 3 to 38m depth.
Original language | English (US) |
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Pages (from-to) | 674-682 |
Number of pages | 9 |
Journal | Journal of Environmental Engineering |
Volume | 132 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2006 |
Keywords
- Aquifers
- Arizona
- Dissolved organic carbon
- Effluents
- Water reuse
ASJC Scopus subject areas
- General Environmental Science
- Environmental Engineering
- Environmental Chemistry
- Civil and Structural Engineering