title: Metal ion and other key water quality constituent attenuation in soil columns.
abstract: A set of soil columns was constructed to simulate discharge of disinfected tertiary treated wastewater to a river via nearby land application or indirect discharge. The system was primarily designed to observe the fate of metal ions and nutrients. The following three experiments were conducted: (1) flow through saturated soils only, which simulates indirect discharge where water is directly applied to groundwater; (2) flow through unsaturated soil followed by saturated flow, which simulates vadose then saturated zone transport; and (3) saturated flow only using ethylene diamine tetraacetic acid-metal chelates, which determined effects of metal organic complexes on metal mobility through the soil. Metal ion attenuation was substantial but not complete in experiments 1 and 2 (removal: 68% Cu2+, 43% Ni2+, 98% Pb2+, and 96% Hg2+), which was somewhat contrary to modeling results. Cyanide attenuation was also monitored (92% removal). In experiment 3, lead attenuation was somewhat reduced (92% removal) and delayed (requiring additional residence time); copper attenuation was significantly reduced (38% removal) and delayed; and nickel concentrations were higher in the 28-day sample (> 80 microg/L) than in the column feed water (58 microg/L). Near-complete denitrification and total phosphorus attenuation were observed. For the water quality constituents studied, unsaturated (vadose zone) transport did not appear to add additional benefit.
authors.affiliation: Kennedy/Jenks Consultants, 303 Second Street, Suite 300 South, San Francisco, CA 94107, USA. jeandebroux@kennedyjenks.com
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Debroux
authors.forename: David W
authors.initials: DW
authors.lastname: Smith
authors.forename: Craig W
authors.initials: CW
authors.lastname: Lichty
authors.forename: Dan
authors.initials: D
authors.lastname: Carlson
mesh_terms: D000641:Ammonia / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002614:Chelating Agents; D008670:Metals / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D008670:Metals; D009566:Nitrates; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002244:Carbon; D000641:Ammonia; D010100:Oxygen