Environmental Engineering Reference
In-Depth Information
1.00E + 10
untreated
BA + DB
BA + DB + Pa64
1.00E + 09
1.00E + 08
1.00E + 07
1.00E + 06
1.00E + 05
1.00E + 04
0
20
40
60
80
100
120
Time (days)
Figure 7.22 Plate counts from POPILE soil incubated in flask microcosms with and
without soil amendments.
7.4.2 LTU pilot project
7.4.2.1 Chemical characteristics
The initial nutrient composition of the soil is provided in Table 7.14. Com-
pared to the optimal C:N:P of 100:10:1 for land farming, and as anticipated
for a highly contaminated soil, the initial nitrogen content in the soil was
found to be an order of magnitude below optimum. During the first 6
months, a commercially available soluble fertilizer, as NH 4 , was applied at
approximately a 0.2% rate to increase the nitrogen concentration in the
system to the target ratio (100:10:1). Although the target concentration could
be reached temporarily, it could not be maintained due to the high concen-
trations of hydrophobic organics bound to the soil matrix that impeded the
soil's ability to absorb moisture and the associated aqueous phase nutrients.
A solid nitrogen addition (0.2% application rate), again a commercially
Table 7.14 Initial Nutrient Analysis of
PAH-Contaminated Soil from the POPILE Site
Concentration
(mg/kg)
Nutrient
Total Kejldahl nitrogen (TKN)
159 ± 18
Nitrite nitrogen (NO 2 -N)
1.88 a
Nitrate nitrogen (NO 3 -N)
17 ± 4
Ammonia nitrogen (NH 3 -N)
4 ± 1
Total phosphate (TP)
456 ± 89
Ortho-phosphate (OPO 4)
32 ± 10
Total organic carbon (TOC)
28,672 ± 3245
a Estimated value, below machine detection limits.
 
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