Corrosion Control by Deposition off CaCO3 Films: Part 3, A Practical Approach for Plant Operators

Low-calcium, low-alkalinity waters, such as those derived from snow melt, pose special problems for the operator because only part of the problem can be worked on C-L diagrams. In addition the treatment process is more complex, since two conditioning chemicals are often required. Example 10 shows how such problems can be handled. Example 10 The analyzed parameters of a river water are 1. Temperature = 25 C 2. TDS = 40 mg/1 3. Alkalinity = 10 mg/1 4. Calcium = 2 mg/1 5. Magnesium = 3 mg/1 6. pH = 8.3 7. Chlorides and sulfates are negligible. The problem is to determine if this water requires conditioning for corrosion control and, if so, how to carry it out. The distribution system is constructed of cast iron.