Ashley Walsh

 Ashley Walsh
Mentor: Dr. Treavor Boyer
College of Engineering
"I initially worked under a PhD candidate to gain research experience, before applying and receiving USP funds to begin my own research."


Environmental Engineering



Research Interests

  • Sustainability
  • Source Separation of Urine
  • Nutrient Recovery and Reuse

Academic Awards

  • UF University Scholars Program
  • W.A. Godron Scholarship
  • University Honors Program


  • Society of Environmental Engineers
  • Society of Women Engineers


  • Shift Leader, Office of Sustainability

Hobbies and Interests

  • Traveling
  • Reading
  • Exploring
  • Eating

Research Description

pH-Stat Experiments to Measure Precipitation Rates of Urine
Urine precipitation causes blockages in urine-collecting systems, leading to build-up and continued maintenance issues as well as restrictions in later treatments when source-separated. The inorganic precipitates in the urine are triggered by the hydrolysis of urea by bacterial urease, most notably struvite and octacalcium phosphate (OCP)—the final precipitate of which is hydroxyapatite (HAP). If the urine is diluted with tap water, calcite forms as well. Since urine contains many nutrients and micropollutants, urine is being studied for possible separation from current wastewater treatment processes. For this, urine-separating toilets and waterless urinals are used to collect undiluted or low diluted urine. Since phosphate is a desirable nutrient, recycling urine into fertilizer harnesses it as a resource and does not allow it to become a pollutant. However, frequent and persistent blockages caused by these precipitates strongly reduces the content of soluble phosphate in urine-separating systems, occurring in traps, connecting pipes, and storage tanks. My research involves investigating the mechanisms of urine precipitation in order to harness potential nutrient gains, and to remedy issues that arise when urine is source separated.