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1. What standards and references are used for the review and approval of engineering designs?

A number of standards and references are used by the Water and Wastewater Treatment Program for the review of engineering designs and as regulatory tools. Review a list of commonly used standards and references.

2. What treatment processes have been utilized on previously approved projects?

Water Treatment Processes:
- Clarification
- Coagulation/Flocculation
- Disinfection – Chlorine, UV, Ozone, Chlorine Dioxide, etc.
- Dissolved Air Flotation
- Filtration
- Ground Water Treatment (Arsenic, Nitrate, Fluoride, TDS, etc. removal) – Absorption, Ion Exchange, Coagulation & Filtration, Membranes, etc.
- Membranes (electrodialysis reversal, micro, ultra, nano, reverse osmosis)
- Sedimentation
- Solids Handling – Thickeners, Presses, Centrifuges, Drying Beds, etc.
- Special Treatment – pH Correction, Polishing, Desalination, Brine Concentration, Evaporation, Distillation, Vapor Recompression, etc.

Wastewater Treatment and Water Reclamation Processes
- Activated Sludge/Extended Aeration
- Clarification (Primary and Secondary)
- Coagulation/Flocculation
- Disinfection - Chlorine, UV, Ozone, etc.
- Dissolved Air Flotation
- Effluent Disposal - Reuse, Recharge, Discharge
- Filtration
- Membranes (micro, ultra, nano, reverse osmosis)
- Odor Control - Chemical Injection Systems, Dry and Wet Scrubbers, Biofilters, etc.
- Oxidation Ditches
- Sedimentation
- Sequencing Batch Reactors (SBRs)
- Solids Handling - Aerobic/Anaerobic Digesters, Thickeners, Presses, Centrifuges, Drying Beds, Cyclones, etc.
- Special Treatment - pH Correction, Polishing, Desalination, Brine Concentration, Evaporation, Distillation, etc.

For more information, please email treatmentplantprogram@maricopa.gov.

3. 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 email treatmentplantprogram@maricopa.gov.

4. What are the separation distance requirements for underground piping?

The separation distance for potable water and sewer pipelines located in the public right-of-way is governed by Arizona Administrative Code (AAC) R-18-5-502.C. The separation distance for reclaimed water pipelines located in the public right-of-way is governed by AAC R-18-9-602.F. The Maricopa Association of Government’s "Uniform Standard Details for Public Works Construction" standards 404-1 and 404-2 detail the separation distance and protection requirements for the installation of potable water, reclaimed water and sewer pipelines for MAG participants.

The separation distance between potable water and sewer pipelines from other pipelines such as non-potable ground, surface, irrigation, storm, industrial, etc., pipelines located in the public right-of-way is not defined by the regulations or MAG standards. The MCESD recommends that these non-potable pipelines:
- Be separated from potable water pipelines as specified by AAC R-18-5-502.C.
- Be located no closer than two feet vertically nor six feet horizontally from all other pipelines unless the non-potable pipeline is encased in at least six inches of concrete or using mechanical joint ductile iron pipe or other materials of equivalent or greater tensile and compressive strength at least 10 feet beyond any point on the pipeline conveyance within the specified minimum separation distance.

The MCESD will determine the separation distance requirements for these pipelines and pipelines not located in the public right-of-way on a case-by-case basis. For more information, download the Uniform Standard Details for Public Works Construction (PDF).

5. What are the design requirements for hose bibbs and hose stations?

The basic design requirements are as follows:
- Appropriate backflow prevention devices (for example vacuum breakers) must be installed at all hose bibbs.
- Signage must be installed at all hose bibbs. Signs for non-potable water hose bibbs should state "Caution: Non-potable Water, Do Not Drink" and display the international 'do not drink' symbol. Signs for reclaimed water hose bibbs should state "Caution: Reclaimed Water, Do Not Drink" and display the international 'do not drink' symbol.
- Hoses and hose racks must be installed at all hose bibbs. This requirement may be waived for unmanned facilities which do not routinely require clean-up or maintenance using hoses.

For more information, please email treatmentplantprogram@maricopa.gov.