Transfers and transformations of zinc in constructed wetlands: Mitigation of a refinery effluent

Autor: Philip B. Dorn, W.B. Gillespie, Manuel L. Cano, W.Bradley Hawkins, John H. Rodgers
Rok vydání: 2000
Předmět:
Zdroj: Ecological Engineering. 14:279-292
ISSN: 0925-8574
DOI: 10.1016/s0925-8574(98)00113-x
Popis: Two pilot-scale wetlands were constructed to facilitate transfers and transformations of Zn in a secondary refinery wastewater effluent. The wetlands (6.1×30.5 m, width×length) were planted with Scirpus californicus and were operated with 24-h nominal hydraulic retention times (HRT). To evaluate wetland performance in terms of Zn removal at two water depths, one wetland was amended with a nominal concentration of 4.0 mg Zn/l as ZnCl2 for 144 days at an operational water depth of 0.3 m, and for an additional 22 days at a water depth of 1 m. The second wetland served as an unamended control. From wetland inflow to outflow, approximately 38% of total recoverable and 65% of soluble Zn was removed during the experiment at the 0.3-m water depth. During the flooded period (1.0-m water depth), approximately 18% of total recoverable and 66% of soluble Zn was removed from the effluent. Toxicity of effluent to Ceriodaphnia dubia Richard and Pimephales promelas Rafinesque decreased from inflow to outflow by ∼54 and 73%, respectively, at the 0.3-m water depth, and by at least 100% at the 1.0-m water depth. These data illustrate successful construction of wetlands for transfers and transformations of Zn from the water column and for decreases in associated toxicity.
Databáze: OpenAIRE
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