This powerpoint presentation outlines the field of tank mixing and potential water quality impacts of distribution system storage facilities. Much of this presentation is based on an AwwaRF sponsored study titled "Water Quality Modeling of Distribution System Storage Facilities". The primary causes of water quality deterioration in water tanks and reservoirs are outlined. Water aging as a primary cause is outlined, along with operational changes that can decrease water age; poor mixing is another cause of water aging including factors such as dead zones, short circuiting, and stratification. Examples of different tank design are provided, as are examples of mixing devices. Various modeling and monitoring tools are discussed that can be used to assess mixing and aging in storage facilities. These tools can also be useful in assessing alternative design, retrofit and operational schemes to improve mixing and decrease water age. Modeling is especially useful for assessing both existing conditions and alternative mitigation schemes. Monitoring can be used to assess whether there is an existing mixing or aging problem. General costs for the various modeling and monitoring methods are listed, and a suggested evaluation process is presented for evaluation of all tanks within a water system in order to prioritize them based on potential problems. Includes tables, figures.
