Research Projects

Human urine accounts for less than 1% in sewage by volume, yet it contributes nearly 80% of the nitrogen, 50% of the phosphorus, and 60% of the potassium excreted by humans. These nutrients are present in much higher concentrations in urine typically 8-11 g/L for nitrogen, 0.2-0.3 g/L for phosphorus, and over 0.8-1.5 g/L for potassium, in contrast, combined domestic sewage contains only 30–70 mg/L N, 4–15 mg/L P, and 10–25 mg/L K. This makes urine nearly 100 times more nutrient-rich and far more suitable for targeted nutrient recovery as an efficient and untapped resource management. Direct utilization of urine is not feasible due to its lower pH, a diverse range of antibiotics and pathogens that can persist in the environment and are not fully removed by conventional recovery methods. Their presence can contribute to antimicrobial resistance and pose risks when the effluent is reused in agriculture or discharged into water bodies. Due to increasing fertilizer demand, undiluted urine is the best source and researchers are working physicochemical methods for their recovery. Unfortunately, antibiotics and pathogens are found in recovered products and pose risk towards their applications. To address these concerns, the proposed project develops a novel hybrid treatment system for adsorption and mineralization of antibiotics and pathogens on membranes. Highly hydrophilic hollow fiber membrane (PVDF/MXene) will be prepared and their surface will be modified by a visible light responsive photocatalyst (TiO₂-g-C₃N₄). Hypothesis is that the source-separated urine will be passed through the shell side of PVDF-Mxene Hollow fiber Nanofiltration Membrane (HNM). The outer surface of these fibers coated with photocatalyst, will generate reactive oxygen species (ROS) capable of degrading a wide range of adsorbed antibiotics, urea, and microbial pathogens, and ultimately reduce fouling. Due to vacuum, clean water will permeate into the membrane lumen, allowing water separation. The concentrated urine, containing ions and degradation byproducts, will undergo struvite precipitation for phosphorus and ammonium recovery (by air stripping). The remaining concentrate will be tested for direct application in hydroponic systems. Scientific Objectives 1. Design and optimization of a photocatalytic HNM reactor for urine treatment. 2. Evaluate the system’s ability to generate ROS, adsorb and degrade pollutants under visible illumination. 3. Analyze fouling behavior, catalyst stability, and degradation performance using real urine. 4. Assess membrane selectivity, water flux, and ion rejection under photocatalytic conditions. 5. Study compositional changes in urine during treatment, including breakdown products and ion formation and their impact on plant growth in hydroponics process. Significance Integration of adsorption, advanced oxidation and membrane separation for safe nutrient recovery and reuse with manageable fouling is the sole of the proposal.