By reducing pHReducing pH ...

1. By reducing pH

Reducing pH means acidifying the water. This can be done by adding hydrochloric or sulphuric acid to the water to lower pH below 6.0 units. Acidifying the water aims to keeps scale forming calcium and magnesium ions in solution as the water moves through the pipeline. Be aware that reducing pH could cause corrosion in metal pipework.

1. Sequestering agent.

Adding sequestering agents (scale inhibitors) such as sodium hexametaphosphate to water may inhibit the precipitation of scale. They may also form a lining on the pipe wall to deter the deposition of scale. One such agent, sodium hexametaphosphate, is marketed under the trade name of ‘calgon’

1. Pipeline operation

To avoid sedimentation and Precipitation of scale forming compounds can be accelerated if there are constrictions in the pipeline. A change in the flow pattern can mean a change in pressure or velocity that will trigger precipitation in susceptible waters. You should ensure that unnecessary bends or constrictions such as a change in pipe diameter, are eliminated. A change to a pipe of larger diameter could be considered if flow velocities are high. Calcium carbonate may also precipitate out if there is a change in water temperature. In situations where the pipeline is near to or at ground surface, it can absorb sufficient heat to cause deposition. This is particularly so where flow is intermittent and long periods of no flow in the hot sunlight are likely.