Test solution no. | Na2S2O8 applied (g) | pH (before heating) |
Observation of treated water |
Comments |
---|---|---|---|---|
1 | 10.01(3) | 9.4 | Clear and colourless solution. No sludge formation. |
Oxidant applied was in large excess. |
2* | 5.00(2) | 10.2 | Clear and colourless solution. No sludge formation. |
Oxidant applied was in excess of about 25%. |
3 | 4.01(6) | 10.9 | Clear and colourless solution. No sludge formation. |
“Optimal” concentration was established with this data point. |
4 | 3.04(4) | 11.6 | Transparent, very pale orange. No sludge formation. |
Inadequate oxidant. |
5 | 2.01(0) | 12.1 | Transparent and bright orange. No sludge formation. |
Inadequate oxidant. |
6 | 1.03(7) | 12.3 | Transparent and bright orange. No sludge formation. |
Inadequate oxidant. |