Proceedings

The water industry is focusing its attention on water quality complaints, particularly the ‘red-water’ complaints linked to corrosion of pipes. Developing a robust conditioning strategy to do this is complex, requiring detailed understanding of water chemistry, pipes materials, potential for corrosion in the network, sampling and assessment of treated and network water quality and the balancing of conflicting water quality needs. The use of the well-known Langelier Saturation Index is very widespread but has its limitations and some water companies are moving away from setting final water quality targets solely based on this index.

The fundamental question has to be asked: why use an index based on calcium carbonate chemistry to control the corrosion of iron pipes? Sometimes the only way of meeting all the water quality needs is to change the treated water quality more fundamentally than just adjusting the pH. This paper discusses Wessex Water’s recent changes to its approach to corrosion control.

Lisa Barrott, MWH, Buckingham Court, Frederick Place, London Road, High Wycombe, Bucks HP11 1JU