For the past four years I have been working with Nils Volkenborn to study the biogeochemistry of innovative wastewater and groundwater treatment systems including permeable reactive barriers (PRBs) and nitrogen removing biofilters (NRBs) with the support of the Center for Clean Water Technology and in collaboration with Cornell Cooperative Extension of Suffolk County. Both technologies rely on nitrogen cycling microbes that convert nitrate to nitrogen gas which is ideal because nitrogen gas is harmless and makes up approximately 80% of our atmosphere.

 

Groundwater sampling event at the bulkhead PRB pilot installed by Cornell Cooperative Extension in collaboration with a local housing association.

An NRB is a residential wastewater treatment system which removes >90% of nitrogen from household wastewater thereby producing effluent with less than 10 milligrams of nitrogen per liter. A PRB is a trench filled with woodchips which is installed underground close to the shoreline to intercept and treat groundwater before it discharges into surface water. Installing PRBs in areas with high submarine groundwater discharge could immediately provide relief from nitrogen pollution of coastal water. Both NRBs and PRBs require woodchips, which is a sustainable material, and they require minimal or no external energy input so they are cost effective and environmentally friendly. The systems rely on microbes that exist naturally in the soil to perform the desired chemical reactions and studies suggest that the systems will continue to remove nitrogen for decades after installation.

 

Laboratory column experiment mimicking full-scale vertical NRB dimensions with replicate dosing frequency treatments

I am currently studying a pilot-scale PRB test site and full-scale NRB sites as well as conducting laboratory experiments to understand how to optimize the performance of these systems. My broad research focus is improving water quality through nutrient removal processes. More specifically I study the hydrological, biological, and chemical dynamics impacting the performance of PRB and NRB systems. As a research assistant, I develop experiments which incorporate planar oxygen optode imaging to answer research questions regarding nitrogen cycling in NRBs and PRBs. I use temperature, oxygen, conductivity and water level sensors to gather field data and evaluate PRB performance. I’m interested in optimizing the nitrogen removal performance and understanding the alternative metabolic pathways that occur in these systems which could lead to pollution swapping.