AGRICULTURAL
Table 1. Interpretation of the results at the different collection points.
Escherichia coli
(E-coli)
Predicted symptoms
include: Skin irritations,
infections & intestinal
disorders
Guideline
Blue Green Algae
Predicted symptoms
include: Skin irritations,
infections & intestinal
disorders
E.coli counts per 100ml at sample points
1 2 3 4 5 6 7 8 9 10
93 9 24,810 10,810 411 48 15 5,980 770,100 249
43 13 11,190 6,910 613 41 17 2,420 155,310 56
Low risk of
gastrointestinal
disorders
E.coli < 130
counts/100ml
Guideline
Significant risk of
gastrointestinal
disorders
E.coli < 200 - 400
counts/100ml
High risk of
gastrointestinal
disorders
E.coli < 400
counts/100ml
Blue Green algae counts at sample points
1 2 3 4 5 6 7 8 9 10
80 < 40 177 603 < 40 < 40 < 40 603 1,931 965
483 < 40 1,207 845 878 845 362 483 965
210
Low risk
Blue Green Algae
< 20,000 cells/ml
Guideline
Algal Pigments
Predicted nuisance
include: Scums &
smells
Slight risk of
gastrointestinal
disorders
E.coli < 130 - 200
counts/100ml
Moderate risk
Blue Green Algae
20,000 - 100,000 cells/ml
High risk
Blue Green Algae
> 100,000 cells/ml
Blue Green algae counts at sample points
1 2 3 4
13 46 8 10
Low risk
Chlorophyll-a < 15ug/l
now under the spotlight.
It is very difficult to reverse the impact
of pollution and natural ways of doing it
could take decades. Doing it by means
of modern technology could also take a
number of years at astronomical costs.
Tests were done in the Sebokeng,
Vanderbijlpark, Sasolburg and
Vereeniging areas and the figures in
Table 1 indicate the points where water
samples were taken and the interpretation
of the results at the different points.
TREATMENT METHODS TO PURIFY
WATER
Air Stripping
In terms of this process, air is used to
remove pollution. The system can effec-
tively remove chemicals, which evaporate
easily. Polluted water is pumped through
a huge compartment and sprayed over
a specific pressed material. The pressed
material allows the water to slowly filter to
the bottom of the tank. A fan simultane-
ously blows air upwards, which results in
the evaporation of the chemicals from the
5 6 7 8 9 10
12 25 62 173 13 76
Moderate risk
Chlorophyll-a 15 - 30ug/l
High risk
Chlorophyll-a > 30ug/l
water. The chemicals aggregate at the
top of the tank, where it is treated, with no
further danger of contamination.
Activated carbon filtering
The process is generally used to remove
pollution. Water is filtered by activated car-
bon filters. The polluted water is pumped
through columns of activating carbon. The
chemicals attach to the surface while the
clear water flows through. It is similar to the
domestic systems being used. The disad-
vantage of the system is that it does not
break down the contamination particles.
In order to remove these particles, the
filters have to be heated and air has to be
pumped through the columns to separate
the particles from the carbon.
Using bacteria bioremediation
Research done in New Delhi indicated that
pollution can be removed economically
from water by using biological products.
Very good results have been achieved
within a period of only two months. It is a
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SENWES SCENARIO | SUMMER 2018
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