Effects of nitrate concentration in interstitial water on the bioremediationof simulated oil-polluted shorelines
XIA Wen-xiang , LI Jin-cheng , SONG Zhi-wen , SUN Ying-jie
DOI:
Received February 26, 2007,Revised July 18, 2007, Accepted , Available online
Volume 19,2007,Pages 1491-1495
- Summary
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Nutrient addition has been proved to be an e ective strategy to enhance oil biodegradation in marine shorelines. To determine the
optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches, nitrate was added to the simulated shoreline
models in the initial concentration of 1, 5 and 10 mg/L. Whenever the NO3-N concentration declined to 70% of its original value,
additional nutrients were supplemented to maintain a certain range. Results showed adding nutrients increased the oil biodegradation
level, the counts of petroleum degrading bacteria (PDB) and heterotrophic bacteria (HB), and the promoted e ciency varied depending
on the concentration of nitrate. Oil degradation level in 5 mg/L (NO3-N) group reached as much as 84.3% accompanied with the
consistently highest counts of PDB; while in 1 mg/L group oil removal e ciency was only 35.2%, and the numbers of PDB and HB
were relatively low compared to the other groups supplemented with nutrients. Although counts of HB in the 10 mg/L group were
remarkable, lower counts of PDB resulted in poorer oil removal e ciency (70.5%) compared to 5 mg/L group. Furthermore, it would
need more NO3-N (0.371 mg) to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group (0.197 mg). In conclusion,
Nitrate concentration in 5 mg/L is superior to 1 and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.
