2,4-D removal via denitrification using volatile fatty acids

摘要

Many countries have waters contaminated with both herbicides and nitrates; however,ninformation is limited with respect to removal rates for combined nitrate and herbicidenelimination. This research investigates the removal of 2,4-D via denitrification, with a particularnemphasis on the effect of adding naturally generated volatile fatty acids (VFAs). The acids werenproduced from an acid-phase anaerobic digester with a mean VFA concentration ofn3153±801mg/L (as acetic acid). Initially, 2,4-D degrading bacteria were developed in an SBR fednwith both sewage and 2,4-D (30–100mg/L). Subsequent denitrification batch tests demonstratednthat the specific denitrification rate increased from 0.0119±0.0039 using 2,4-D alone ton0.0192±0.0079 gNO3-N/g VSS per day, when 2,4-D was combined with natural VFAs from thendigester. Similarly, the specific 2,4-D consumption rate increased from 0.0016±0.0009 using 2,4-Dnalone to 0.0055±0.0021 g 2,4-D/g VSS per day, when using 2,4-D plus natural VFAs. Finally, anparallel increase in the percent 2,4-D removal was observed, rising from 28.33±11.88 using 2,4-Dnalone to 54.17±21.89 using 2,4-D plus natural VFAs.