Related Experiment Videos
Characterisation of materials causing discolouration in potable water systems
1Department of Chemical and Process Engineering, University of Sheffield, Newcastle Street, Sheffield S1 3JD, UK. A.Seth@sheffield.ac.uk
Summary
Flushing water mains mobilizes iron, which is the primary cause of discoloured water complaints. Metal concentrations during flushing are independent of pipe material, diameter, or age.
Area of Science:
- Environmental Science
- Water Treatment Engineering
- Materials Science
Background:
- Discoloured water is a major source of customer dissatisfaction for UK water suppliers.
- Current understanding of the mechanisms and materials causing discolouration during water mains flushing is limited.
- Effective strategies for preventing red water events require characterization of mobilised materials.
Purpose of the Study:
- To characterise the materials mobilised during water mains flushing that are responsible for water discolouration.
- To investigate the relationship between flushing, pipe characteristics, and the concentration of mobilised materials.
- To identify the dominant materials contributing to discoloured water events.
Main Methods:
- A collaborative monitoring program of mains flushing was conducted by the University of Sheffield and two UK water companies.
- Discrete samples were collected during flushing operations involving pipes of varying materials, diameters, ages, source water types, and hydraulic conditions.
- Analysis focused on identifying and quantifying the materials present in the mobilised water, with a focus on metals and turbidity.
Main Results:
- Iron was identified as the dominant material mobilised during flushing, regardless of the pipe material.
- A direct correlation was observed between turbidity, iron, and manganese concentrations in all samples.
- Lead, copper, aluminium, and zinc were also detected, with their mobilisation concentrations being independent of pipe material, diameter, or age.
Conclusions:
- Iron is the primary material responsible for discolouration events triggered by water mains flushing.
- Turbidity, iron, and manganese levels are key indicators of potential discolouration.
- Water quality management strategies should consider the consistent mobilisation of iron and other metals irrespective of pipe infrastructure specifics.