At Jefferson Peaks, the overall energy consumption for the plant was reduced by approximately 37 percent and the cost saving was approximately 53 percent. The additional saving was attributed to the reduced demand charges from the electricity company.
Implementation of the NPXpress technology required minimal capital improvement to the existing wastewater treatment plants. The simple payback period was calculated by comparing the capital investment and the savings for the two full scale plants. The simple payback period for Mapleton and Jefferson Peaks was 3.1 months and 4.6 months respectively.
Since the conversion of the Jefferson Peaks and Mapleton treatment works, the elimination of supplemental carbon translates to further savings on chemical cost and the related operation and maintenance costs.
Patent Award and On-going Effort
The NPXpress technology was awarded a patent in September 2011. The technology is being installed at six other American Water wastewater treatment plants as part of the company's overall "green" initiatives. The technology has demonstrated promising capabilities to achieve wastewater treatment and nutrient removal in a sustainable way and provided opportunities for wastewater utilities to design, build, and operate an energy neutral wastewater treatment plant.
About the Author: Mark W. LeChevallier, Ph.D., is currently the Director of Innovation & Environmental Stewardship at American Water, the largest publicly traded U.S. water and wastewater utility company, providing drinking water, wastewater and other related services to approximately 15 million people in more than 30 states and parts of Canada. Circle No. 290 on Reader Service Card
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