Electrochemical Nutrient Extraction from Digestate

The proposed technology addresses the need for mitigation of the impacts of animal agriculture on the environment via recovery of phosphorus and nitrogen. Concentrated animal feeding operations create significant amounts of waste in the form of manure digestate; disposal at a cost of $1.6B. Microbial electrolysis cells have been explored as a chemical free, energy efficient method of extracting nutrients from wastewater while generating renewable energy sources. Initial results with batch-fed, single-chamber reactors show soluble phosphorus removal up to 85%. Energy consumption was significantly less than that needed by extraction methods based on aeration and chemical additions. Faraday and the University of Illinois will build upon prior work to demonstrate the potential scability of the microbial electrolysis cell technology, identify pulsed waveforms that enhance nutrient recovery from manure digestate, minimize or eliminate cathode scale formation, and optimize performance metrics such as phosphate precipitation rates and energy consumption. Faraday will demonstrate the potential for an economically-viable, sustainable, industrial-scale nutrient extraction process that reduces agricultural cost while co-generating hydrogen, predicated upon the strengths and flexibility of FARADAYIC® pulse-processing, in particular increased control over dynamics and mass transport. Phase II will build upon this effort by designing and optimizing an alpha-scale system.