Environmental Engineering Reference
In-Depth Information
grinded, and three particles sizes (0.2-2.0, 0.125-0.2, and <0.125 mm) were prepared for
further evaluation.
33.11 Batch- and Column-Scale Testing
All tests were carried out with simulated runoff solution with spiked concentrations of ive
contaminant categories (Table 33.3). Pollutant removal eficiency, hydraulic performance,
and metal leaching were all studied before Fe-Osorb and Zn-Osorb were selected for
ield-scale testing and commercial development because of the combination of their rela-
tively low production costs, low toxicity, long-term reactivity, and stability.
In batch tests, results showed that all ive Osorb-metal composites were successful in
removing a signiicant percentage of most tested contaminants from water. Observed
results included ~99% removal of both petroleum hydrocarbons and pharmaceuticals
(Table 33.4), 96% removal of pesticides (Figure 33.4), and 30%-50% removal of nutrients.
No signiicant removal of antifreeze was observed.
Column-scale testing conirmed that the Osorb-metal composites do not negatively
affect the hydraulic performance of a bioretention system, and removal results were con-
sistent to batch-scale results with one notable exception: as the amount of Osorb-metal
TABLE 33.3
Composition of Simulated Runoff
Parameter
Pollutants
Concentration (mg/L)
Petroleum hydrocarbons
Motor oil
1000
Nutrients
Nitrate (NO
3
-N)
10-20
Phosphate (PO
4
-P)
10
Herbicide
Atrazine (C
8
H
14
ClN
5
)
0.5-1.0
Pharmaceuticals
Ethinylestradiol (C
20
H
24
O
2
)
0.5-1.0
Triclosan (C
12
H
7
Cl
3
O
2
)
0.5-1.0
Antifreeze/de-icer
Ethylene glycol (C
2
H
6
O
2
)
1000
TABLE 33.4
Residual Concentrations of Runoff Pollutants after 1-Min Treatment with Osorb Composites
(1% W/V)
Motor Oil (mg/L)
Ethinylestradiol (μg/L)
Triclosan (μg/L)
Particle Size (mm)
Particle Size (mm)
Particle Size (mm)
Osorb-Metal
Composites
>0.2
0.125-0.2
<0.125
>0.2
0.125-0.2
<0.125
>0.2
0.125-0.2
<0.125
Al-Osorb
3.8
2.5
0.6
10.3
3.1
0.1
50.1
10.3
3.1
Fe-Osorb
4.1
3.6
0.5
8.2
1.8
0.1
42.6
3.1
0.9
Mg-Osorb
3.7
2.8
0.9
7.8
2.0
0.1
48.5
8.5
4.2
Ni-Osorb
3.6
3.0
0.1
7.6
3.8
0.1
32.9
7.8
5.1
Zn-Osorb
2.8
2.0
0.5
10.0
2.4
0.1
31.4
8.8
4.5
