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.

Links

Publisher Full Text

Authors

Debroux JF, Smith DW, Lichty CW, Carlson D

Institution

Kennedy/Jenks Consultants, 303 Second Street, Suite 300 South, San Francisco, CA 94107, USA. jeandebroux@kennedyjenks.com

Source

Water environment research : a research publication of the Water Environment Federation 84:2 2012 Feb pg 134-43

MeSH

Ammonia
Carbon
Chelating Agents
Metals
Nitrates
Oxygen
Phosphorus
Soil
Soil Pollutants
Time Factors
Water Pollutants, Chemical

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22515063