College
College of Engineering
Mentor Information
Daniel Yeh
Description
Nitrogen pollution poses serious risks to human and ecological health, driving toxic algal blooms, degrading fisheries, and threatening communities that rely on clean water resources, making sustainable nitrogen removal technologies essential. This study evaluates whether zeolite—a naturally porous, cation‑adsorbing mineral with high NH₄⁺ capacity—can be biologically regenerated through nitrification and denitrification, eliminating the costly chemical regeneration typically required for long‑term use. A lab‑scale Nutrient Capture System (NCS) was constructed using a granular activated carbon (GAC) bed followed by two tidal‑flow zeolite beds to simulate the Modified Ludzack‑Ettinger process. Synthetic wastewater containing approximately 70 mg/L total nitrogen and 260 mg/L COD was treated under controlled recirculation ratios, with beds inoculated using activated sludge and monitored twice weekly for COD, TN, NH₄⁺, NO₂⁻, NO₃⁻, alkalinity, and pH. Preliminary results show 60% total nitrogen removal and 95% COD removal at a 1:1 recirculation ratio, with nitrogen species transformation confirming effective nitrification in the zeolite beds and denitrification in the GAC bed. The zeolite maintained stable biological activity over extended periods without chemical regeneration, demonstrating its viability as a sustainable media for decentralized wastewater treatment. These findings suggest that zeolite bioregeneration can significantly reduce operational costs, eliminate chemical regenerants, and support long‑term nutrient removal in remote or small‑scale systems. Future work will refine recirculation strategies, quantify full‑scale applicability, and further evaluate how biologically regenerated zeolite can enhance resilient, low‑maintenance nitrogen management.
Biological Regeneration of Zeolite for Long-Term Nitrogen Management in Onsite Wastewater Treatment Systems
Nitrogen pollution poses serious risks to human and ecological health, driving toxic algal blooms, degrading fisheries, and threatening communities that rely on clean water resources, making sustainable nitrogen removal technologies essential. This study evaluates whether zeolite—a naturally porous, cation‑adsorbing mineral with high NH₄⁺ capacity—can be biologically regenerated through nitrification and denitrification, eliminating the costly chemical regeneration typically required for long‑term use. A lab‑scale Nutrient Capture System (NCS) was constructed using a granular activated carbon (GAC) bed followed by two tidal‑flow zeolite beds to simulate the Modified Ludzack‑Ettinger process. Synthetic wastewater containing approximately 70 mg/L total nitrogen and 260 mg/L COD was treated under controlled recirculation ratios, with beds inoculated using activated sludge and monitored twice weekly for COD, TN, NH₄⁺, NO₂⁻, NO₃⁻, alkalinity, and pH. Preliminary results show 60% total nitrogen removal and 95% COD removal at a 1:1 recirculation ratio, with nitrogen species transformation confirming effective nitrification in the zeolite beds and denitrification in the GAC bed. The zeolite maintained stable biological activity over extended periods without chemical regeneration, demonstrating its viability as a sustainable media for decentralized wastewater treatment. These findings suggest that zeolite bioregeneration can significantly reduce operational costs, eliminate chemical regenerants, and support long‑term nutrient removal in remote or small‑scale systems. Future work will refine recirculation strategies, quantify full‑scale applicability, and further evaluate how biologically regenerated zeolite can enhance resilient, low‑maintenance nitrogen management.
