Description:

Resource Efficient Microbial Bioprocesses for Shortcut Nitrogen and Phosphorus Removal from Wastewater  

Conventional wastewater treatment is an energy intensive process that consumes as much as 3% of the total electrical energy demand in the United States, in large part due to high aeration demands. Moreover, conventional treatment processes often do not remove nitrogen or phosphorus, the discharge of which can lead to eutrophication in surface waters and the death of aquatic life. Emerging processes in biological wastewater treatment include energy saving methods for shortcut nitrogen removal such as anaerobic ammonia oxidation (anammox) via the partial nitritation/ anammox (PN/A) process, which does not require organic carbon and requires less aeration than conventional processes. Application of the PN/A process to mainstream wastewater such as that in Chicago, subject to low temperatures and fluctuations in flow due to wet weather events, remains a challenge due to the growth of undesirable nitrite oxidizing bacteria at low temperatures and the low growth rate of anammox. My research focuses on the integration of shortcut nitrogen removal processes with biological phosphorus removal (which can facilitate phosphorus recovery via struvite precipitation) in the challenging environment of mainstream wastewater in the Chicago area. I have investigated two treatment trains; a one-stage process (single reactor) and a two-stage process (separate reactors for nitrogen and phosphorus removal), both of which demonstrated robust combined nitrogen and phosphorus removal at lower retention times and energy demand than conventional processes. The application of such technology holds potential for decreasing the carbon and ecological footprint of wastewater treatment across the globe.

Bio:
Paul Roots is a fifth-year Ph.D. candidate at Northwestern University studying low energy biological methods for nutrient removal from wastewater. Before attending Northwestern he graduated from the University of Illinois at Chicago with a B.S. in civil engineering and worked for two years as a consultant in the solid waste industry.