Environmental Engineering Reference
In-Depth Information
concentrations in surface waters may reach values far above the value proposed as
provisional guideline for drinking water by the WHO of 1
g/l for MCYST-LR.
When a well is installed in the vicinity of a river or lake shore, part of the pumped
water originates from surface water, which is called bank filtrate. When bank filtrate
is utilized for drinking water, it has to be ensured that concentrations in pumped
water are below the threshold. For that reason, it is important to understand the
sorption and degradation processes during the sub-surface passage of the bank
filtrate water. Batch experiments using surface water and characteristic porous
materials are a first approach for such an examination.
In a batch experiment microcystin, dissolved in water, was brought into contact
with porous sediments. The original concentration was 1
m
g/l. In aqueous sediments
microcystin is subject to sorption and biodegradation. In order to obtain retardation
factors and degradation rates batch experiments can be run. The decrease of
the concentration was measured at several time instants after the first contact. The
following table and figure shows example concentrations for five instants of time
(Gr
m
utzmacher
2006
) (Table
10.1
) (Fig.
10.1
):
In MATLAB
€
the values are entered as two line vectors:
®
tfit = [0.25 1 2 4 8];
cfit = [0.7716 0.5791 0.4002 0.1860 0.1019];
Table 10.1 Example data-set from microcystin batch experiment
Time (h)
0.25
1
2
4
8
Concentration (
m
g/l)
0.9405
0.5537
0.3994
0.1509
0.0592
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
1
2
3
4
5
6
7
8
Fig. 10.1 Quadratic curve fitting for example batch experiment
