What information is required for a blending plan approval?
The following information should be included in the blending plan submittal package:
- A brief narrative describing the dilution and contaminant sources and the methodology used to achieve proper blending. The narrative should detail how proper blending is to be maintained using manual or automatic controls, safety interlocks, online analyzers and operational procedures.
- An analysis of possible failure modes which might affect the blending system and identification of any special conditions such as emergency or seasonal operation of the blending system.
- If construction work is associated with the blending plan then design drawings are required as part of the blending plan submittal. Otherwise, a sketch showing the existing configuration of the blending system, including major system components connected to the blending system such as wells, reservoirs and booster pumps should be included in the blending plan submittal package.
- Identification of the Point-of-Entry downstream from the blending point.
- Laboratory analyses and reports documenting the contaminant concentrations of all dilution and contaminant sources. If sufficient historical water quality data are available a 90th percentile value should be calculated for various sources' contaminant concentrations.
- The nominal flow rate and contaminant concentrations for each of the dilution sources.
- The nominal flow rate and contaminant concentrations for each of the contaminant sources.
- If a dilution or contaminant source is a well then the Arizona Department of Water Resources (ADWR) well identification number and the physical address of the well should be provided.
- The physical address of the blending point. If a physical address is not available then the cross streets or GPS coordinates of the blending point should be submitted.
- Identification of the point downstream of the blending point which will provide proper mixing of the blended stream (i.e. a static mixer or storage reservoir) prior to the blended stream being discharged into the water distribution system.

For more information, please call 602-372-2861.

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