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1. Evaluation of Physicochemical Treatment Technologies for Landfill Leachate Induced Dissolved Organic Nitrogen (DON).

   Md Redowan Rashid, Md Ashik (June 2023, AEESP Research and Education Conference, Northeastern University, June 20-23, 2023)

   Landfill leachate contains high levels of dissolved organic nitrogen (DON) that can be detrimental to aquatic life and water quality because it promotes the growth of harmful algal blooms (HABs). This study used physicochemical treatment technologies such as Fenton treatment and Granular Activated Carbon (GAC) adsorption to assess the breakdown and removal of landfill leachate-induced DON. The physicochemical treatments were applied to effluents of two bioreactors treating blended wastewater and landfill leachate. Bioreactor-1 (R1) was fed with high organic landfill leachate, and bioreactor-2 (R2) was fed with low organic landfill leachate. For R1 effluent, the Fenton treatment removed 66±9.2% COD and 52.4±8.7% DON at an optimum dosage of 200mg/L H2O2 and 1000mg/L FeSO4.7H2O. On the other hand, GAC removed 94.4±4.9% COD and 85.9±4.6% DON at an optimum dosage of 10g/L GAC. For R2 effluent, the Fenton treatment removed 75.8±6.6% COD and 60.3±3.2% DON at an optimum dosage of 200mg/L H2O2 and 1000mg/L FeSO4.7H2O. On the contrary, GAC treatment removed 92.2±4.3% COD and 92.3±3.7% DON at an optimum dosage of 10g/L GAC. Moreover, fluorescence spectrophotometry combined with parallel factor analysis (PARAFAC) was employed to provide insight into the DON degradation mechanisms. The study found that Fenton treatment and GAC adsorption both can effectively reduce DON in landfill leachate. However, GAC treatment was superior to Fenton treatment in eliminating DON from landfill leachate, while Fenton treatment may convert DON into inorganic nitrogen. The study emphasizes properly handling landfill leachate to avoid nitrogen contamination and harmful algal blooms in aquatic ecosystems. 

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2. Co-treatment of landfill leachate and municipal wastewater: what we’ve learned and what’s next?

   Zhao, Renzun (May 2025, AEESP 2025 Conference)

   ABSTRACT Landfill leachate management is a critical challenge for the municipal solid waste (MSW) industry due to its significant environmental impact and high operational costs. In the United States, sanitary landfilling remains the primary MSW disposal method, with more than half of generated waste landfilled as of 2022. The U.S. generates between 7.1 and 11.3 billion gallons of landfill leachate annually, with up to one-third of landfill operational costs dedicated to leachate management. Leachate production can persist for decades after landfill closure, necessitating long-term management strategies. Around 61% of landfill leachate is disposed of at publicly owned treatment works (POTWs). These facilities face challenges in treating hazardous leachate components, including high Total Nitrogen levels, UV quenching substances (UVQS), refractory dissolved organic nitrogen (rDON), elevated temperature landfill (ETLF) leachate, micro- and nanoplastics (MP/NP), and per- and polyfluoroalkyl substances (PFAS). This presentation will explore the historical context of landfill leachate management and the challenges of co-treating leachate at POTWs. It will also identify emerging solutions and technologies aimed at improving treatment processes, enhancing environmental protection, and reducing costs. Addressing these challenges is crucial for minimizing the environmental footprint of landfill operations and ensuring compliance with regulatory standards. 

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3. Near-term potential of organic waste management infrastructure for soil carbon sequestration in rangelands

   https://doi.org/10.1088/2634-4505/ac970f  

   Hall, A. L.; Potts, M. D.; Silver, W. L. (November 2022, Environmental Research: Infrastructure and Sustainability)

   Abstract Contemporary food and agricultural systems degrade soils, pollute natural resources, and contribute to greenhouse gas emissions. The waste output from these systems, however, can be repurposed as an agricultural input, reducing emissions associated with organics disposal while actively sequestering atmospheric carbon in soils—thus transitioning the sector from a carbon source to a carbon sink. This research estimates the near-term technical and economic potential of utilizing composted organic feedstocks as a soil amendment to mitigate climate change and improve long-term soil quality, in line with California’s organics diversion policies, by connecting food scraps and organics residuals in California’s municipal solid waste to existing infrastructure and working lands in the state. The multi-objective spatial optimization results indicate considerable carbon sequestration benefits in the range of −1.9 ± 0.5 MMT CO₂eq annually, by applying compost to 6 million hectares of California rangelands at a price of approximately $200 per ton, presenting a cost-effective climate change mitigation strategy within proposed federal sequestration credits. Expanding composting capacity is predicted to increase the total amount of carbon sequestered while reducing the cost per ton and per hectare treated. This model aids decision makers in considering the technical, economic, and institutional potential of actively managing the State’s organic materials in municipal waste streams for climate change mitigation. 

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4. Fate and Transport of the Biologically Treated Landfill Leachate Induced Dissolved Organic Nitrogen (DON)

   Md Ashik Ahmed*, Md Redowan (June 2023, AEESP Research and Education Conference, Northeastern University, June 20-23, 2023)

   This study evaluated the performance of sequencing batch reactors (SBR) in the fate and transport of dissolved organic nitrogen (DON) using a blend of wastewater and landfill leachate. Most nitrogen removal methods concentrate on inorganic nitrogen, whereas some biological processes add DON to the effluent. Two reactors were introduced with wastewater and landfill leachate of high and low organic carbon and compared them to a reactor without leachate. DON transformation, characterization, and microbial community dispersion were examined to understand the effects of leachate-induced effluent DON on the biological nitrogen removal process. The ammonium removal efficiencies were found 96, 97, and 98%; COD removal efficiencies were 75, 59, and 63%; and total nitrogen (TN) removal efficiencies were 83, 86, and 88%, for R1, R2, and R3, respectively. The effluent nitrate concentrations were found 1.67 ± 0.89 (R1), 3.05 ± 2.08 (R2), and 1.31 ± 1.30 (R3) mg/L and DON went down from 9.67 ± 2.5 to 6.02 ± 2.8 mg/L (R1), 9.29 ± 3.4 to 7.49 ± 3.6 mg/L (R2), and 3.59 ± 1.6 to 2.08 ± 1.1 mg/L (R3). Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and excitation-emission matrices (EEMs) with parallel factor (PARAFAC) analysis were used to characterize DON. Microbial community analysis was also conducted. Leachate-induced DON discharge's environmental effects were assessed using in-situ aquatic ecosystem algal bioassay. SBR system removed most inorganic nitrogen species and a small amount of leachate-induced DON. The study emphasizes the need for independent investigations to assess their effects on receiving water bodies. 

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5. CO2 Sequestration using BOF slag: Application in landfill cover

   Reddy, K.R.; Kumar, G.; Gopakumar, A.; Rai, R.K.; Grubb, D.G. (July 2018, International Conference on Protection and Restoration of the Environment XIV)

   Fugitive methane (CH4) and carbon dioxide (CO2) emissions at municipal solid waste (MSW) landfills constitute one of the major anthropogenic sources of greenhouse gas (GHG) emissions to the atmosphere. In recent years, biocovers involving the addition of organic-rich amendments to landfill cover soils is proposed to promote microbial oxidation of CH4 to CO2. However, most of the organic amendments used have limitations. Biochar, a solid byproduct obtained from gasification of biomass under anoxic or low oxygen conditions, has characteristics that are favorable for enhanced microbial oxidation in landfill covers. Recent investigations have shown the significant potential of biochar-amended cover soils in mitigating the CH4 emissions from MSW landfills. Although the CH4 emissions are mitigated, there is still considerable amount of CO2 that is emitted to the atmosphere as a result of microbial oxidation of CH4 in landfill covers as well as the CO2 derived from MSW decomposition. Basic oxygen furnace (BOF) slag is a product of steel making has great potential for CO2 sequestration due to its strong alkaline buffering and high carbonation capacity. In an ongoing project, funded by the U.S. National Science Foundation, the potential use of BOF slag in landfill covers along with biochar-amended soils to mitigate both CH4 and CO2 emissions is being investigated. This paper presents the initial results from this study and it includes detailed physical and chemical and leachability characteristics of BOF slag, and a series of batch tests conducted on BOF slag to determine its CH4 and CO2 uptake capacity. The effect of moisture content on the carbonation capacity of BOF slag was also evaluated by conducting batch tests at different moisture contents. In addition, small column experiments were conducted to evaluate the gas migration, transport parameters and the CO2 sequestration potential of BOF slag under simulated landfill gas conditions. The result from the batch and column tests show a significant uptake of CO2 by BOF slag for the tested conditions and demonstrates excellent potential for its use in a landfill cover system. 

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