Heavy metal retention and partitioning in a large-scale soil-aquifer treatment (SAT) system used for wastewater reclamation.
Soil aquifer treatment (SAT) of wastewater relies on extensive biogeochemical processes in the soil and aquifer to achieve large-scale and economic reclamation of municipal effluents. Removal of trace metals from the wastewater is a prime objective in the operation, but the long-term sustainability of the adsorptive filtration capacity of the soils is an open question. Solid/solution partitioning (measured by the distribution coefficient, K(d)) and solid/solid partitioning (measured by selective sequential dissolution, SSD) of heavy metals were measured in soils sampled from active recharge basins in a wastewater reclamation plant and were compared to the adjacent pristine dune. K(d) values for the adsorption of Cu, Ni and Zn, measured in short-term adsorption experiments positively and significantly correlated with solution pH. Quantitative estimation of Cu, Ni and Zn adsorption on multi-sorbents indicated that surface adsorption and precipitation on Fe oxides and/or carbonate may be the major mechanisms of metal retention in these soils. SSD analyses of metal partitioning in soils exposed to approximately 20yr of effluent recharge showed that all solid-phase components, including the most stable 'residual' component, competed for and retained added Cu and Zn. Copper preferentially partitioned into the oxide component (32.0% of the soil-accumulated metal) while Zn preferentially partitioned into the carbonate component (51.6% of the soil-accumulated metal).
Lin
Chunye
C
Department of Soil and Water Sciences, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel. linchuny@agri.huji.ac.il
Shacahr
Yiftach
Y
Banin
Amos
A
D000327:Adsorption; D005618:Fresh Water / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007557:Israel; D019216:Metals, Heavy / Q000032:analysis*; D008956:Models, Chemical; D012987:Soil / Q000032:analysis*; D013054:Spectrophotometry, Atomic; D014865:Waste Disposal, Fluid; D018508:Water Purification
D019216:Metals, Heavy; D012987:Soil