Removal of selenate in simulated agricultural drainage water by a rice straw bioreactor channel system.
Removal of selenium (Se) from agricultural drainage water is important in protecting wetland wildlife. Three flow-through bioreactor channel systems (BCSs), each with three channels filled with rice (Oryza sativa L.) straw, were set in the laboratory to determine removal of selenate [Se(VI)] (1020 microg L(-1)) from drainage water with a salinity of 10.4 dS m(-1), a pH of 8.1, and a nitrate (NO3-) range of 0 to 100 mg L(-1). Results showed that the rice straw effectively reduced Se(VI) during 122 to 165 d of the experiments. Calculation of Se mass in the three BCSs showed that 89.5 to 91.9% of the input Se(VI) was reduced to red elemental Se [Se(0)], where 96.6 to 98.2% was trapped in the BCSs. Losses of each gram of rice straw were almost equal to the removal of 1.66 mg of Se from the drainage water as a form of red Se(0), indicating that rice straw is a very effective organic source for removing Se(VI) from drainage water.
Zhang
Yiqiang
Y
Department of Environmental Sciences, University of California, Riverside, CA 92521-0424, USA.
Frankenberger
William T
WT
D000383:Agriculture; D019149:Bioreactors; D005374:Filtration; D012275:Oryza; D064586:Selenic Acid; D018036:Selenium Compounds / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000302:isolation & purification*
D018036:Selenium Compounds; D014873:Water Pollutants; D064586:Selenic Acid