Kyushu University · Engineering
Professor Mitali Nag's research lab specializes in environmental remediation and waste management, with a primary focus on stabilizing hazardous heavy metals and mitigating greenhouse gas emissions from municipal solid waste and incineration residues. The lab investigates innovative, low-cost treatment technologies—such as using natural zeolites (e.g., mordenite), fishbone-derived hydroxyapatite, and pozzolanic bottom ash—to immobilize toxic metals like lead and zinc in fly ash. A key research direction involves understanding and controlling nitrous oxide emissions during landfill aeration and nitrification processes, particularly under varying temperature and oxygen conditions. The lab emphasizes sustainable, nature-based solutions for enhancing the environmental safety of waste-derived materials.
Figures are computed from collected data and may differ slightly.
Landfill aeration can accelerate the biological degradation of organic waste and reduce methane production; however, it induces nitrous oxide (N2O), a potent greenhouse gas. Nitrification is one of the pathways of N2O generation as a by-product during aerobic condition. This study was initiated to demonstrate the features of N2O production rate from organic solid waste during nitrification under three different temperatures (20°C, 30°C, and 40°C) and three oxygen concentrations (5%, 10%, and 20%
Investigation of nitrous oxide production potential during in situ aeration in an old landfill site revealed that increased temperatures and oxygen content inside the landfill site are potential factors for nitrous oxide production. Temperatures within the range of optimum nitrification process (30-40°C) induce nitrous oxide formation with high oxygen concentration as a by-product of nitrogen turnover. Decrease of oxygen content during nitrification leads increase of nitrous oxide production, wh
The current study investigated the sorption process of heavy metals, especially lead (Pb2+) and Zinc (Zn2+), in Municipal Solid Waste Incineration (MSWI) fly ash applying natural zeolite, namely mordenite, as an inexpensive adsorbent to assess its feasibility for the treatment of fly ash. Batch experiments were performed to investigate the effects of the influential parameters, such as metals initial ion concentration, dosage of adsorbent, liquid to solid (L/S) ratio, and equilibrium concentrati
Incineration is a common technique worldwide for treating Municipal Solid Waste (MSW). However, incineration residues (e.g., bottom and fly ash) require special treatment to prevent environmental risks due to the high content of heavy metals. The present study evaluated the stabilization degree of Pb, a toxic heavy metal in MSW incineration fly ash (IFA) treating by size-fractionated natural fishbone (FB) hydroxyapatite (HA). Bones from various fish species were used at different size fractions
Stabilizing heavy metals in Municipal Solid Waste Incineration (MSWI) fly ash by using natural zeolite is one of the state-of-the-art technologies. The current study focused on the sorption process of heavy metals by applying mordenite, an inexpensive natural zeolite adsorbent, and assessing the efficacy of the treatment of fly ash. Batch experiments were conducted to investigate the effects of the influential parameters, such as the initial metal ion concentration, the liquid-to-solid (L/S) rat
Fine-fraction of Municipal Solid Waste (MSW) incineration bottom ash (IBA) contains amorphous silica, known as pozzolan is one of the potential heavy metal stabilizers in MSW incineration fly ash (IFA) by forming the cementitious compounds of calcium silicate hydrates (C - S - H) and calcium aluminate hydrates (C-A-H). The technique can be called the 'Ash-by-Ash Treatment Method' (AATM). To optimize the AATM, effects of water (L/S ratios) and IBA amounts (IFA/IBA ratios) were examined in this st
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