Analysis of nitrogen speciation and removal in direct potable reuse in El Paso, Texas

Oluwaseye Michael Owoseni, University of Texas at El Paso


Population growth and increasing demand for potable water is causing a need for additional sources to water portfolios in areas with water scarcity. Direct Potable Reuse (DPR) is gaining recognition in these regions and ensuring appropriate measures for the removal of nitrogen and other contaminants cannot be overemphasized. Two nitrogen species, nitrate and nitrite are known to cause harmful effects on young infants below the age of six months. El Paso Water Utilities conducted a pilot test for DPR to ascertain the viability of DPR as an additional source to the current water portfolio. Non-chlorinated secondary clarifier effluent from a wastewater treatment plant was treated through several barriers for different contaminants. The effectiveness of the barriers provided in the treatment train for nitrogen species removal was evaluated in this paper. These barriers include the wastewater treatment plants nitrification process, denitrification filters, and nanofiltration /reverse osmosis membranes. To generate confidence in the results of analyses of the nitrogen species, the accuracy or reliability of the measurements for nitrogen species was evaluated. The inter and intra laboratory comparisons used showed good relationships indicating accuracy. The denitrification filters had challenges with variabilities in influent water nitrogen speciation and was removed from the pilot test. The NF/RO membranes were consistent in nitrogen removal and performed stably during the pilot test. Nitrification inhibition rate tests performed on the wastewater showed low rates in comparison to a standard model. Overall, the pilot test helped in identifying key factors that will enhance nitrogen removal in the DPR facility.

Subject Area

Environmental engineering

Recommended Citation

Owoseni, Oluwaseye Michael, "Analysis of nitrogen speciation and removal in direct potable reuse in El Paso, Texas" (2016). ETD Collection for University of Texas, El Paso. AAI10118233.