FINAL DESIGN
The AP6600-LX reverse osmosis system manufactured by AMPAC USA is the recommended alternative. It is able to treat 6,600 gallons per day, so it will take just over 2.25 days of all-day operation each year to treat the wastewater. It has a recovery rate of 50-75% so of the 15,000 total gallons to be treated, 7,500-11,250 gallons would be recovered as treated permeate water and 3,750-7,500 gallons would be rejected as concentrate water. It also has a rejection rate of 98%, so the permeate water will have a TDS ranging from 0.005-0.007 ounces TDS/gallon, less than the 0.04 ounces TDS/gallon maximum incoming wastewater requirements for the Williams WWTP. The RO system is able to set the pH anywhere between 6.5-10.0 so the pH will be able to be set below the maximum incoming wastewater pH requirements at the Williams WWTP of 9. The permeate water will be able to be disposed of to the Williams WWTP or reused onsite. Onsite reuse will save 150-225 dollars each year assuming a 0.02 USD/gallon water cost.
The concentrate water will be sent to the rainwater catchment basin that is now repurposed as an evaporation basin. The basin is currently able to hold 225,000 gallons and has an HDPE liner, and so would not require an ADEQ aquifer protection permit. The concentrate would have 0.36-0.72 ounces TDS/gallon equating to approximately 187 pounds of solids each year in the evaporation pond. These solids can be disposed of in the local landfill.
This design would also require an 8,000-gallon plastic storage tank to store permeate water after treatment.
The figure on the right displays the pretreatment process, along with approximate wastewater volumes, conditions, and criteria.
To learn more about the AP6600-LX reverse osmosis system visit the Design Alternatives page.
