A Hybrid Electrodialysis/Electrolysisn Unit for Combined Nitrate Removal and Conversion from Agricultural Wastewater

Nitrate is currently the most prevalent groundwater pollutant in Northern America primarily fromagricultural activities and changing nitrogen input to the land surface.State-of-the-art treatmenttechnologies such as reverse osmosis ion exchange and electrodialysis suffer from brinemanagement cost associated with nitrate removal. The core technology developed through thisSBIR project will be a hybrid electrodialysis (ED)/electrolysis (EL) unit to efficiently removenitrates from waste water and subsequently convert them to molecular nitrogen thereby eliminatingbrine management cost. The project objectives are: (1) To develop bi-functional electrodes thatoperate efficiently in both electrodialysis (nitrate removal) and electrolysis (nitrate conversion)mode; (2) Assemble and test 1 cm2 hybrid electrodialysis/electrolysis unit and evaluate theirperformance and durability for continuous removal and conversion of nitrates in different feedwater sources.The target is to achiever nitrate conversion efficiency >75% fresh water recovery efficiency >85%and energy efficiency >75%.If successful the proposed project will improve water recovery andreuse from agricultural return flows and improve nutrient management. An economical process oftreating nitrates with no brine generation can impact >1000 community drinking water systems thathave nitrate levels greater than maximum contaminant level of 45 mg/L.