Question #1: Why is the vapor pressure of a compound important in remediation? Question #2: Based on class information and selected readings, briefly discuss the obstacles or threats associated with...

1. Why is the vapor pressure of a compound important in remediation?
Vapor pressure may be defined as; the pressure which is exerted by a compound in the
airspace above its pure state. It can also be described as; a measure of distribution of a compound
or its partitioning between its pure form and the airspace above it. If the vapor pressure of the
compound is significantly high then, it would prefer to be in the vapor phase means; it would
reflect a considerably volatile nature and vice-versa (Otterpohl et al., 2003).
Now, this property might prove to be helpful in remediation of such contaminants that
have high vapor pressures for instance; Volatile Organic Compounds (VOCs). VOCs may also
be described as; compounds with vapor pressures which can exceed 1 millimeter (mm) of
mercury (Hg) at temperatures that are usually met (15ºC to 20ºC) (Malmén et al., 2003).
To understand it clearly, we might take the example of “Soil Venting technology” which
can also be termed similar to “Soil Washing” except that it applies gases in place of liquid for the
purpose of transportation of pollutants out of the subsurface. In soil venting, air is pumped into
bore holes and is sucked out via other holes or through pipes that are placed in a horizontal mode
(Otterpohl et al., 2003).
Because of such pumping of air, Volatile Organic Compounds are converted into their
vapor phase and could be extracted from the subsurface. To induce the procedure, hot air may
also be used as; it can enhance the vapor pressure of a compound and in this way, may force the
vaporization of contaminants in a rapid manner (Malmén et al., 2003).
2. Briefly discuss the obstacles or threats associated with establishing clean up objectives.
Though, because of accumulation of waste stuff in a considerable quantity, it has become
necessary to remove the same otherwise, it might prove to be life threatening yet, this cannot be
called an easy target after all. In fact, there could be found various obstacles that are associated
with waste treatment for instance; it‟s not always possible to define the extent of the crisis or the
basis of trouble (Otterpohl et al., 2003).
Besides, development of an effective strategy to tackle the issue can prove to be another
challenge associated with establishment of clean up objectives. According to researchers, such
plan can be launched only after getting an idea about the source of problem and clean-up
standards. Moreover, arrangement of necessary funds to implement the clean up techniques is
another issue that should be resolved successfully (Malmén et al., 2003).
In addition, technology applied for the purpose of waste removal can be a modification of
traditional technique(s). Such variations are introduced on case by case basis and can further
enhance the application costs because of need of proper confirmation of their effectiveness
otherwise; these might slow down the waste treatment procedure and can defeat the purpose
(Otterpohl et al., 2003).
3. How important is temperature and pH in chemical oxidation and why?
Chemical oxidation can be utilized for the purpose of conversion of chemically
dangerous pollutants to harmless or less toxic compounds which are more stable, less
transportable, and/or static. The agents used for oxidation are termed as; oxidizing substances
which can involve ozone, hydrogen peroxide, hypo-chlorites, chlorine, and chlorine dioxide etc
elements/compounds (Malmén et al., 2003).
Such oxidants can be used for destruction of several toxic chemicals (for example;
unsaturated aliphatic and aromatic compounds) in a rapid as well as efficient manner, but their
implementation can prove to be successful in only those circumstances which could be termed
„optimum‟ for their activity. These may include proper temperature as well as pH conditions
(Otterpohl et al., 2003).
The importance of such circumstances can be understood via taking the example of
Ozone gas. Ozone can oxidize pollutants directly or indirectly. It can work in an efficient manner
only in such pH conditions that can be termed „acidic‟ by nature and increment in pH condition
might induce the decomposition of Ozone into OH-radicals.
1. O3 + OH
-
→ HO2
-
+ O2
2. O3 + HO2- →
•
OH + O2
•-
+ O2
In the same way, an increment in temperature may also induce the degradation of Ozone
in to hydroxyl radicals and thus; may affect the oxidation process governed by Ozone in an
adverse manner.
4. What kind(s) of technology is good for removing contamination from deep seated sites in
the subsurface with high concentration of contaminants and why?
Though, there could be found several waste treatment plans, but all of them...