Why Arizona Honored by Water & Wastes Digest

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Project Name: Why Utility Co. Project

Location: Why, Arizona

Footprint: Lot size approx. ¼ acre (70X60 ft)

Category: Water

Project Goals

The town of Why, AZ, like so many towns in the southwestern portion of the United States, had high levels of arsenic in their well water, well beyond the allowable limit. Why Utility Company has three water wells to supply the town’s 100 service connections and regular population of approximately 400, and the increased winter population or seasonal visitors. Of the towns' three wells, all had arsenic levels which exceeded the allowable limit set by the Environmental Protection Agency. Their water required treatment in order to be in compliance with the Arizona Dept. of Environmental Quality as well as the US Environmental Protection Agency limits. Why, Arizona needed a cost efficient and water efficient solution to this problem.

Project Challenges

The main challenge was getting the town's arsenic levels which were in excess of 150 ppb down below the Maximum Contaminant Level of 10 ppb as determined by the EPA and to also satisfy the requirements the Arizona Department of Environmental Quality.

Filtronics pilot tested the water with a combined flow from two of their wells. The testing indicated the need for two-stage filtration. The primary stage was coagulation and filtration with Filtronics Electromedia? filter. The arsenic from the primary stage was reduced to 11 to 18 ppb. The second filter, an adsorptive unit, dropped the arsenic to less than 3 ppb.

Surprisingly, with some adjustments to the treatment chemistry, the filter in the primary stage consistently reduces the arsenic from 150 ppb to1 or 2 ppb, lessening the demand on the second stage. The full scale adsorptive filters now need only take a side stream of about 30% of the flow, rather than 100%. The lower than expected usage and lower levels of arsenic to the absorptive filters will extend the life of the adsorptive media by a factor of more than three. Overall operating costs have been significantly reduced by the performance of the primary filter. It is likely with further testing, the secondary stage will be unnecessary.

Start Date November of 2005

Finish Date September of 2008

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