Development of an effective bioremediation technology for volatile ...
Development of an effective bioremediation technology for volatile ...
Development of an effective bioremediation technology for volatile ...
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tel-00730195, version 1 - 7 Sep 2012<br />
Table I.h (cont’nd):<br />
Source <strong>of</strong><br />
Pollut<strong>an</strong>t<br />
BTEX<br />
(fuel)<br />
Electron<br />
Acceptor(s)<br />
KNO3<br />
(electron<br />
acceptor)<br />
<strong>an</strong>d<br />
ammonium<br />
polyphosph<br />
ate<br />
(nutrients)<br />
(<strong>an</strong>aerobic)<br />
I.2.3.3. Natural processes<br />
Result(s) Reference(s)<br />
- The data indicated that the BTEX in nitrateenriched<br />
aquifer was biodegraded in-situ under<br />
denitrifying conditions.<br />
-BTEX declined by 78% in water from the<br />
monitoring well which was most contaminated<br />
initially <strong>an</strong>d by nearly 99% in water from one<br />
<strong>of</strong> the extraction wells.<br />
-At one <strong>of</strong> the extraction wells, down-gradient<br />
<strong>of</strong> the monitoring well, nitrate appeared in<br />
signific<strong>an</strong>t concentrations after week 124; this<br />
appear<strong>an</strong>ce coincided with a marked decline (><br />
90%) in monoaromatic concentration.<br />
Gersberg et<br />
al. 1995<br />
Intrinsic <strong>bioremediation</strong>, which is also known as natural attenuation or passive<br />
<strong>bioremediation</strong>, is <strong>an</strong> environmental site m<strong>an</strong>agement approach that relies on naturally<br />
occurring microbial processes <strong>for</strong> petroleum hydrocarbon removal from groundwater, without<br />
the engineered delivery <strong>of</strong> nutrients, electron acceptors or other stimul<strong>an</strong>ts (Curtis <strong>an</strong>d<br />
Lammey, 1998; Clement et al., 2000; Kao <strong>an</strong>d W<strong>an</strong>g, 2000; Kao <strong>an</strong>d Prosser, 2001;<br />
Widdowson, 2004; Maurer <strong>an</strong>d Rittm<strong>an</strong>n, 2004; Reinhard et al., 2005; Kao et al., 2006).<br />
Natural <strong>bioremediation</strong> removes <strong>an</strong>d decreases org<strong>an</strong>ic pollut<strong>an</strong>ts from m<strong>an</strong>y contaminated<br />
sites (Röling <strong>an</strong>d Verseveld, 2002). It is more cost <strong>effective</strong> th<strong>an</strong> engineered conditions but it<br />
takes more time <strong>for</strong> org<strong>an</strong>ic biodegradation (Kao <strong>an</strong>d Prosser, 1999; Andreoni <strong>an</strong>d Gi<strong>an</strong>freda,<br />
2007).<br />
Mineralization <strong>of</strong> org<strong>an</strong>ic compounds in groundwater under natural <strong>bioremediation</strong> is,<br />
just like with engineered situations, connected to the consumption <strong>of</strong> oxid<strong>an</strong>ts such as oxygen,<br />
nitrate <strong>an</strong>d sulfate <strong>an</strong>d the production <strong>of</strong> reduced species such as Fe +2 , Mn +2 , H2S, CH4 <strong>an</strong>d<br />
CO2 (Lovley, 1997; Bolliger et al., 1999). Some studies <strong>of</strong> BTEX removal from contaminated<br />
groundwater through natural in-situ <strong>bioremediation</strong> are summarized in Table I.i.<br />
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