Environmental Engineering Reference
In-Depth Information
Reservoir
Sand
Sand
Sand
Sand
Sand
Sand
Fig. 1
Experimental layout
C3. For mechanical protection, a 10 cm sand layer was applied to the top and to the
bottom of the filter bed. The filter media composition was defined in previous pilot
scale studies based on their hydraulic conductivity behavior.
Each column was fed with a synthetic highway runoff by regulated flow pumps.
This synthetic solution was obtained from the dilution of Zinc acetate dehydrate
(CH
3
COO)
2
Zn x 2H
2
O), Copper (II) acetate monohydrate ((OOCCH
3
)
2
Cu × H
2
O)
and Lead (II) acetate trihydrate ((CH
3
COO)
2
Pb × 3H
2
O). The maximum solubility
values for these reagents, at 20°C, are: 430, 72, and 410 g/L, respectively.
Laboratory analyses were carried out according to Standard Methods
[7]
.
Reagent grade chemical products and ultra-pure water were used. All glassware
coming in contact with the samples was washed with nitric acid and rinsed with
de-ionized water.
After the samples were collected, the physicochemical parameters (pH, conductivity
and temperature) as well as the hydraulic head were measured immediately. The
sample was then filtered on a 0.45 mm porosity membrane, and acidified to pH < 2
with HNO
3
. All the samples where then preserved at 4°C. Pb was analyzed by
Graphite Furnace Atomic Absorption Spectrometry (GFAAS), while Zn was
analyzed by Inductive Coupled Plasma Atomic Emission Spectrometry (ICP-AES).
Cu was analyzed by GFAAS or ICP. Detection limits were of 0.001 mg/L (GFAAS)
and 0.01 mg/L (ICP-AES) for Cu, 0.002 mg/L (GFAAS) for Pb and 0.01 mg/L
(ICP-AES) for Zn. Materials and experimental details are presented in
[6]
.
