The biggest challenge to the distribution operator is to maintain the quality of the water established at the treatment plant until it reaches the customer’s tap. Since 40 percent of recent waterborne illness outbreaks are attributed to distribution deficiencies, it is very important that distribution operators protect the system from events or situations that will degrade water quality. Distribution operators should have knowledge of water chemistry, hydraulics, biology and water quality parameters. Coupling this knowledge with a solid maintenance program can lead to smaller differences in treatment plant to customer tap water quality. Some factors that greatly affect water quality are pathogens, corrosion, scaling, turbidity and hardness.
Pathogens cause serious or fatal health issues. These organisms can reproduce under conditions of poor operation or maintenance practices or excessive water age. Pathogens can be reduced by attaining proper disinfection residual levels and keeping them consistent. Chemical and biological characteristics can cause metallic decomposition that causes corrosion. Deposits of calcium carbonate on distribution piping can also lead to water quality issues. This problem can usually be attributed to pH, alkalinity, total dissolved solids, temperature and hardness. Turbidity is suspended particles in the water that can indicate microbial growth in the distribution system. Turbidity can be the cause of taste, odor issues and color issues, as well as prohibit disinfection. Hardness is when water contains high concentrations of calcium and magnesium.
As the operator learns to tackle these issues and situations, the water quality can be maintained in the distribution system. As you continue to improve your distribution operation and maintenance practices, here are a few key areas to monitor or consider to help with improvement.
- Proactive unidirectional flushing
- Storage tank cleaning and maintenance
- Water age
- Limit dead-end lines
- Establish cross-connection control programs
- Establish leak detection programs
- Monitor water quality frequently
- Train your personnel
- Communicate with the treatment plant often
- Disinfect new and repaired lines properly