Electrodialytic nutrient recovery from wastewater

Nutrient pollution contributes to global water quality issues in the form of eutrophication, which leads to algal blooms and dead zones due to oxygen depletion, as well as public health issues such as methemoglobinemia. A major source of that nutrient pollution is inadequately treated sewage, in particular, from non-sewered sanitation systems (NSSS) which are not designed to remove nutrients before discharge into the environment. The USA and global populations reliant on NSSS are large and growing. Further, the EPA estimates that over 2.6 million existing NSSS may require technical treatment improvements for nitrogen removal due to their location in nitrogen-sensitive watersheds [2]. The forms of nitrogen and phosphorus exiting from these systems is almost entirely as ammonium (NH4+) and phosphate (PO43-), respectively. Triangle Environmental’s Technology Innovation: Electrodialytic Nutrient Recovery (ENR), selectively removes these ions from wastewater streams, creating separate nutrient-free and nutrient-rich steams.Electrodialysis is a proven technology for desalination and treatment of certain wastewater streams but requires more research for application to NSSS. ENR can be implemented as an add-on polishing step to existing NSSS so that final effluent can meet discharge limits or incorporated into other advanced NSSS under development to meet the growing demand. Most traditional approaches to advanced NSSS for nutrient removal are reliant on biological process. In comparison, ENR provides a much higher level of removal efficiency and reliability while having a much smaller footprint. These strengths enable NSSS to be more viable in areas increasing in population density or with environmental conditions requiring smaller systems. Triangle Environmental expects to be able to sell the final product within a range of $5,000-10,000, a competitive price point for septic upgrades and price that can be fully covered by tax credits in some states.While the uncontrolled release of these ions contributes to environmental concerns, these ions are critical nutrients for agriculture. The capture and reuse of them using ENR not only mitigates pollution but provides an increasingly scarce commodity for global food production. ENR can improve the quality of water discharged and generate a nutrient-rich product ready for agricultural application.By achieving the following milestones, Triangle Environmental aims to ready ENR for household wastewater treatment applications: M1. Prototype construction and model solution testing. M2.Characterization of membrane fouling. M3. Evaluation of ENR performance with different household wastewater mixtures. M4. Projection of full-scale sizing, energy demand, and membrane life.