Sedona Wastewater Worry

By Staff Writer | Sedona.biz
 
(Sedona, Arizona) - The Sedona City Council met this week to discuss alternatives for the off-site disposal of treated wastewater (effluent) produced by the City's Wastewater Reclamation Plant.

The City has hired the engineering firm Burgess & Niple, Inc. to help it identify and analyze the various disposal alternatives.

As background, the Arizona Department of Environment Quality (ADEQ) does not currently permit the City of Sedona to dispose of treated wastewater (effluent) beyond the property lines of the wastewater facility.  The City currently disposes of its effluent either by spraying it into the air, allowing it to evaporate from holding ponds, or through plant transpiration (a loss of water by a plant by evaporation).

The City currently disposes of approximately 1.1 million gallons of effluent a day.  This requires a significant amount of land. The wastewater facility covers 426 acres that can only absorb 1.25 million gallons of effluent a day, a mere 150,000 gallons more than now, based on its current disposal methods.

Based on the anticipated population growth, the City estimates that it may need to dispose of 2.5 million gallons of effluent per day.

The City is, therefore, investigating off-site disposal options.  However, ADEQ requires that off-site effluent must be certain quality standards which the City wastewater treatment process may not always be able to achieve.  Consequently, the City is also investigating other on-site disposal alternatives.

Failure to dispose of effluent properly could impact the City's ability to connect to the sewer system and possible fines by ADEQ because of permit violations.

The preferred on-site option is a storage basin that can hold up to 73 million gallons (about 30 days of maximum disposal need).

There are four off-site ways to dispose of effluent: 

1) blending effluent with "raw water" from streams and lakes, known as indirect potable reuse.  Water from streams and lakes is called "raw water" because it tends to contain more pollutants than treated wastewater.  However, since the City's drinking water is well water, it would need to be specially treated and it would also require pumping the effluent uphill to a point upstream;

2) injecting the effluent into the Verde River Basin's underground water bed (aquifer), known as "recharge" since it is stored in the groundwater.  Since new home development along the Verde River is constrained by the available water supply, effluent injected into the Verde River Basin's aquifer could be sold by the City of Sedona to home builders as water credits, providing an additional source of revenue to the City.  Burgess & Niple estimate that the City's recharge could permanently support 85 new homes per year or 8,500 homes over a 20 year period.  Burgess & Niple estimates that the City could earn $3,360 per home, or $28.5 million over a 20 year period.  The Arizona Department of Water Resources (ADWR) recently allowed Prescott Valley to sell its effluent to developers. This option would require miles of pipeline;

3) using the effluent for recreational use by creating fishing ponds or lakes on a golf course.  This may require that the wastewater have a higher level of treatment since it might be consumed by people;

4) point discharge which means injecting the effluent into an off-site location.  Unlike "recharge," discharging the effluent means it couldn't be reused and there is no opportunity to sell it to developers. This option would require miles of pipeline.

The City Council decided to direct Burgess & Niple, Inc. to focus primarily on option 2) "recharge" since it could create additional revenue for the City.

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