Independent Evaluation of: East Midlands Water Company GAC Filter
Commissioned by: Dr D Walke, East Midlands Water Co
Comments
The East Midlands Water Co BTU 1 filter proved to be extremely effective at removing both free and total chlorine, this effectiveness remained at a high level >93% throughout the projected life of the filter (40,000 litres).
There were also good removal rates for aluminium and copper, these being between 77% and 94% removal.
The filter was also tested to identify any problems with pollutants being "dumped" back into the outlet water from the filter medium. This test was carried out after a throughput of 35,000 litres towns mains (STW plc). Samples were taken immediately before and after the filter and analysed for:-
Aluminium, copper, iron, lead, manganese, nitrate, chloride and total hardness.
No increase in the concentrations of any of the above were detected in the output water, ie there was no evidence of "dumping" taking place.
Results
Filter after 20,000 litres towns mains.
Flow rate of test solution through the filter was 1.5 litres per minute.
Analysis
Analyte
Chlorine (free)
Chlorine (total)
Aluminium
Copper
Iron
Lead
Manganese
Nitrate as NO
Chloride
Total hardness (as CaCO) |
inlet
conc*
2.50
2.60
0.87
1.99
1.72
1.84
0.90
20.90
43
205 |
outlet
conc
0.10
0.19
0.11
0.21
0.74
0.74
0.70
8.14
43
205 |
% removal
96
93
87
89
57
60
22
61
Nil
Nil |
*All concentration values are given in Parts Per Million (ppm) which are equivalent to milligrams per litre (mg/1).
Results
Analyte
Clorine (free)
Chlorine (total)
Aluminium
Copper
Iron
Lead
Manganese
Nitrate as NO
Chloride
Total hardness (as CaCO) |
inlet
conc*
1.84
2.00
0.62
2.02
1.65
1.42
3.6
18.92
32
190 |
outlet
conc
N.D.
0.04
0.09
0.12
1.05
0.04
2.4
8.8
32
190 |
% removal
>99
98
85
94
36
72
33
53
Nil
Nil |
*All concentration values are given in Parts Per Million (ppm) which are equivalent to milligrams per litre (mg/l)
> = greater than N.D. = none detected
|
