Development of a constructed wetland water treatment system for selenium removal: incorporation of an algal treatment component.
On the basis of the fact that algae have the ability to volatilize substantial quantities of selenium (Se), we investigated the concept of including an algal pretreatment unit into a constructed wetland system for the removal of Se from river water entering the Salton Sea. Of six different algal strains tested, the most effective in terms of Se volatilization and Se removal from the water column was a Chlorella vulgaris strain (designated Cv). Cv removed 96% of Se (supplied as selenate) from the microcosm water column within 72 h, with up to 61% being removed by volatilization to the atmosphere. X-ray absorption spectroscopy revealed that the major forms of Se likely to be accumulated in an algal-wetland system are selenomethionine, a precursor of volatile Se formation, and elemental Se. Our results suggest that the inclusion of an algal pretreatment unit within a constructed wetland water treatment system should not only enhance the efficiency of Se removal but also significantly reduce the risk of the buildup of ecotoxic forms of Se by promoting the biological volatilization of Se.
Department of Plant and Microbial Biology, University of California , Berkeley, California 94720-3102, United States.
Jung-Chen
JC
Huang
María C
MC
Suárez
Soo In
SI
Yang
Zhi-Qing
ZQ
Lin
Norman
N
Terry
D001673:Biodegradation, Environmental; D002708:Chlorella / Q000378:metabolism*; D016566:Organoselenium Compounds / Q000378:metabolism*; D044444:Scenedesmus / Q000378:metabolism*; D018036:Selenium Compounds / Q000378:metabolism*; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods; D053833:Wetlands
D016566:Organoselenium Compounds; D018036:Selenium Compounds; D014874:Water Pollutants, Chemical