Advanced Treatment Technologies

Advanced Treatment Technologies

Nutrient removal in onsite waste treatment technologies

Nitrogen and phosphorus are nutrients that are critical for plant growth, but uncontrolled release of them into watersheds can lead to algal blooms that negatively impact both human and environmental health. While agricultural runoff represents the largest source of this pollution, human waste is a source of increasing concern, especially in areas served by onsite waste treatment systems (OWTS) such as septic tanks that are close to sensitive watersheds. OWTS systems present a particular challenge because of their small scale: technologies for nutrient removal used in municipal wastewater treatment do not typically work at the household or community scale.

We are pursuing several technologies to help close this gap in onsite treatment, including novel applications of mineral-based ion exchange materials and development of new composite materials for nutrient sorption, and recently published research into the use and regeneration of Polonite and clinoptilolite. In partnership with Triangle Environmental, we have also demonstrated a new membrane-based system that removes nitrogen and phosphorus from OWTS effluent that has potential to meet even the most demanding discharge standards at a competitive cost.

Presentations on previous research in nutrient removal:

Natural silicate minerals for nutrient removal from blackwater, Lena Trotochaud (2020).

Silicate minerals provide non-biological removal of ammonium and phosphate ions from oniste wastewater treatment effluent, Mariana Vasquez (2020).

Advanced sorbents for stormwater treatment

The Duke Center for WaSH-AID is working with Oldcastle Infrastructure, a CRH Company, to explore technologies to remove nitrogen from urban stormwater.

Nutrient pollution is a widespread and challenging problem in urban stormwater management. Stormwater runoff carries nitrogen and phosphorus from fertilizer, pet waste and other sources to creeks, rivers, and lakes, where these nutrients can contribute to algal blooms. Algal blooms can be toxic to humans and aquatic life and are exacerbated by climate change. Increases in impervious cover as a result of human activities increase stormwater management challenges.

Our researchers have developed a novel inorganic/organic material that shows strong performance for nitrogen and phosphorus removal in laboratory tests. This non-biological media is active immediately upon installation. The media is adaptable to use in stand-alone filter cartridges as well as mixed-media beds and can easily be retrofitted into existing bioretention or filtration systems. 

A pilot system has been built at Elon University to test the sorbent using real stormwater. The system, designed and built by Triangle Environmental, will pump stormwater from a catchment basin into the columns on the pilot unit during a rain event. The columns can be packed with a variety of sorbent media or doses of sorbent media to compare nutrient removal performance.

Past Projects

Applied Electrochemistry

Electrochemistry has been applied in a number of contexts relevant to water and sanitation, including oxidation of pollutants and additive-free generation of chlorine for disinfection. Our research includes improved mechanistic understanding of peroxide generation by diamond electrodes, and application of this knowledge to improve the efficiency of electrochemical disinfection of blackwater. Other projects include using electrochemical manipulation to eliminate malodor associated with sanitation technologies, which often presents a significant barrier to user acceptance and adoption. Our team also investigates the use of electrochemistry as a non-destructive characterization tool for water filtration membranes.


In many areas of the world, intestinal parasites called helminths are endemic and responsible for malnutrition and stunted growth. They are transmitted through fecal contamination of the soil, and are especially difficult to eradicate from water supplies due to the tough outer layers of their eggs which protect them from disinfectant chemicals. Our team, together with researchers from Elon University and Virginia Tech, have developed an electroporation method which uses a high-intensity electric field to disrupt the outer shell of the egg, enabling disinfectants like chlorine to enter and inactivate it.