A study published in Environmental Science and Ecotechnology reports a self-powered platform that turns wastewater into a source of clean water and fertilizer. Researchers from Temple University and the New Jersey Institute of Technology developed a closed-loop system that links electrically assisted forward osmosis (eFO) with a microbial desalination cell (MDC), allowing electricity produced by wastewater-fed microbes to drive nutrient and water recovery.
The system addresses the growing need to recover resources from wastewater amid water scarcity, energy constraints, and fertilizer demand. Conventional treatment focuses on pollutant removal, but the integrated design enables the recovery of water, nutrients, and energy in one stable process. The eFO module uses an osmotic gradient to pull water from wastewater toward a magnesium sulfate draw solution. When a mild electric field is applied, magnesium ions migrate back toward the wastewater side, reacting with ammonium and phosphate to form struvite, a slow-release fertilizer.
The MDC component houses electroactive microorganisms that oxidize organic matter, generating electrons that support desalination. The researchers harvested this microbial electricity, stored it in a 400-farad supercapacitor, regulated the voltage, and fed it back to the eFO unit. At bench scale, the MDC generated more than 7.0 milliwatts, while the eFO module consumed less than 1.0 milliwatt. Compared with the control, water flux rose by 57%, struvite recovery increased from 0.25 to 0.71 grams at 1.8 volts, and total desalination efficiency improved by 45%. At higher voltage, struvite recovery reached 1.03 grams at 3.8 volts.
To guide operation, the team developed a hybrid model combining mechanistic transport equations with a support vector machine (SVM), enabling prediction of struvite recovery, chemical oxygen demand (COD), conductivity, and power output across different conditions. The authors emphasized that the study shows how wastewater treatment can be redesigned as a connected resource-recovery loop rather than separate unit operations. The internal feedback, where microbial electricity directly controls ion movement and fertilizer formation, makes the approach more practical for nutrient-rich streams such as livestock wastewater.
The results point to applications in decentralized wastewater treatment, agricultural waste management, and future resource-recovery facilities. However, scale-up will require engineering work: the MDC produced enough power for the eFO module, but hydraulic retention times, module sizing, struvite harvesting, membrane scaling, and electrode durability need optimization. A techno-economic assessment estimated a bench-scale net treatment cost of $10.2 per cubic meter, falling to $3.3 per cubic meter in an engineering scale-up scenario.
The study was partially supported by the U.S. Bureau of Reclamation (Award# 13761566 and R22AC00433) and the NSF/BSF project (Award# 2215387). Publication was funded in part by the Temple University Libraries Open Access Publishing Fund. The full study is available at https://doi.org/10.1016/j.ese.2026.100730.
