TABLE 4. Comparison of Biological Treatment Technologies*
Type/cost ($/yd^3 )
Land treatment
$30-$90
Bioventing
$50-$120
Bioreactor
$150-$250
Advantages- Can be used for in situ or ex
situ treatment depending upon
contaminant and soil type - Little or no residual waste
streams generated - Long history of effective
treatment for many petroleum
compounds (gasoline, diesel) - Can be used as polishing
treatment following soil
washing or bioslurry treatment - Excellent removal of volatile
compounds from soil matrix - Depending upon vapor
treatment method, little or no
residual waste streams to
dispose - Moderate treatment time
- Can be used for in situ or ex
situ treatment depending upon
contaminant and soil type - Enhanced separation of many
contaminants from soil - Excellent destruction efficiency
of contaminants - Fast treatment time
Disadvantages- Moderate destruction efficiency
depending upon contaminants - Long treatment time relative to
other methods - In situ treatment only practical
when contamination is within
two feet of the surface - Requires relatively large,
dedicated area for treatment
cell - Treatment of vapor using
activated carbon can be
expensive at high
concentrations of contaminants - System typically requires an air
permit for operation - High mobilization and
demobilization costs for small
projects - Materials handling
requirements increase costs - Treated solids must be
dewatered - Fullscale application has only
become common in recent
years
* Chemical Engineering magazine.high degree of public acceptance of bioremediation vs. alternatives such as incineration.
The Resource Conservation and Recovery Act (RCRA) defines hazardous waste as
specifically listed wastes or as wastes that are characteristically toxic, corrosive, flamma-
ble, or reactive. Wastes at this site fit certain of these categories.
Table 4 compares three biological treatment technologies currently in use. The type of
treatment, and approximate cost, $/ft
3
($/m
3
), are also given. Since petroleum hydrocar-
bons are less than 500 ppm at this site, biological land treatment will be chosen as the
treatment method.
Looking at the range of costs in Table 4 shows a minimum of $30/yd^3 ($39/m^3 ) for
land treatment and a maximum of $250/yd^3 ($327/m^3 ) for bioreactor treatment. This is a
ratio of $250/$30 = 8.3:1. Thus, where acceptable results will be obtained, the lowest cost
treatment technology would probably be the most suitable choice.