The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water
Table 3
Mean concentration, standard deviation (only for THM4), minimum and maximum of the 4 studied THMa (), and mean and value of the two samples for MXb and bromatec () before and after the filtration experiments. Percentage of change in bold.
Reverse osmosis
Activated carbon pitcher-type filter
1 L
75 L
150 L
Before
After
Before
After
After
After
Chloroform (TCM)
Mean (SD)
7.3 (0.06)
3.21 (0.04)
3.46 (0.14)
0.31 (0.03)
0.70 (0.03)
1.17 (0.48)
Min–max
(7.25–7.39)
(3.17–3.27)
(3.31–3.61)
(0.27–0.33)
(067–0.74)
(0.88–1.89)
% change
−56
−91
−80
−66
Bromodichloromethane (BDCM)
Mean (SD)
15.09 (0.18)
0.58 (0.04)
8.75 (0.31)
0.99 (0.10)
1.99 (0.05)
2.20 (0.07)
Min–max
(14.94–15.33)
(0.56–0.64)
(4.48–9.13)
(0.88–1.09)
(1.92–2.04)
(2.12–2.28)
% change
−96
−89
−77
−75
Dibromochloromethane (DBCM)
Mean (SD)
35.48 (0.29)
0.10 (0.12)
27.25 (0.91)
2.82 (0.24)
6.15 (0.17)
6.67 (0.15)
Min–max
(35.08–35.72)
(0.02–0.27)
(26.40–28.26)
(2.58–3.11)
(5.90–6.26)
(6.47–6.80)
% change
−99
−90
−77
−75
Bromoform (TBM)
Mean (SD)
69.44 (0.89)
0.18 (0.25)
64.76 (1.86)
6.91 (0.65)
16.42 (0.37)
16.69 (0.19)
Min–max
(68.71–70.58)
(0.03–0.55)
(62.68–66.64)
(6.37–7.78)
(16.15–16.97)
(16.53–16.97)
% change
−99
−89
−75
−74
Sum of 4 THMs (THM4)
Mean (SD)
127.31 (0.87)
4.07 (0.41)
104.23 (3.18)
11.04 (1.00)
25.26 (0.56)
26.74 (0.72)
Min–max
(126.64–128.59)
(3.82–4.68)
(101.07–107.64)
(10.20–12.31)
(24.64–26.01)
(26.00–27.65)
% change
−97
−89
−76
−74
MX
Mean
0.8
<0.5
0.6
<0.5
<0.5
<0.5
Min–max
(0.7–0.8)
(all < 0.5)
(0.5–0.6)
(all < 0.5)
(all < 0.5)
(all < 0.5)
% change*
—
—
—
—
Bromate
Mean
2.3
0.5
2.90
2.6
3.10
2.55
Min–max
(2.2–2.4)
(all <0.5)*
(2.9-2.9)
(2.3–2.8)
(2.8–3.4)
(2.5–2.6)
% change
—
−12
7
−12
THM4 and all 4 species: concentration in g/L, limit of quantification of 0.4 g/L, all means .
bMX: concentration in ng/L, limit of quantification of 0.5 ng/L, all means .
cBromate: concentration in g/L, limit of quantification of 0.5 g/L, all means .
*Percentages of change when values were under the limit of quantification (LOQ) for MX and bromate are not reported due to high uncertainty in the estimate.
