Electricity generation and emission characteristics during the poultry litter and natural gas co-combustion process has rarely been studied. In this study, a Stirling engine was successfully integrated into the existing lab-scale swirling fluidized bed combustion system in order to further investigate the poultry litter and natural gas co-combustion process. Electricity, gaseous emissions, particulate matter (PM), and fly ash composition were analyzed under various operating conditions. Results indicated that the electricity reached 905 W under a water flow rate of 13.1 L/min and an engine head temperature of 584 °C. It was found that excess air (EA) ratios between 0.79 and 1.08 can relatively produce more electricity with lower emissions. At a secondary air (SA) height of 850 mm, secondary air/total air (SA/TA) ratios between 0.22 and 0.44 may significantly reduce NO_x and CO emissions. By increasing the mixing ratio (MR), SO₂ was reduced while NO_x increased at the beginning of co-combustion process but then decreased again. Additionally, PM results were lower than Maryland emissions standards. The fly ash results showed a higher nutrient content (close to 16%). This study shows the possibility of using poultry litter as a sustainable energy source for energy production while emitting lower emissions in the small decentralized combustion system.

This study systematically compares the environmental and economic performance of three wastewater treatment systems: constructed wetlands (CWs), microbial fuel cells (MFCs), and their integration (CW–MFC). Lab-scale units of each system were constructed using a multi-media matrix (gravel, zeolite, and granular activated carbon), composite native wetland species (Juncus effusus, Iris sp., and Typha angustifolia), carbon-based electrodes (graphite), and standard inoculum for CW and CW–MFC. The MFC system employed carbon-based electrodes and proton-exchange membrane. The experimental design included a parallel operation of all systems treating domestic wastewater under identical hydraulic and organic loading rates. Environmental impacts were quantified across construction and operational phases using life cycle assessment (LCA) with GaBi software 9.2, employing TRACI 2021 and ReCiPe 2016 methods, while techno-economic analysis (TEA) evaluated capital and operational costs. The key results indicate that CW demonstrates the lowest global warming potential (142.26 kg CO₂-eq) due to its reliance on natural biological processes. The integrated CW–MFC system achieved enhanced pollutant removal (82.8%, 87.13%, 78.13%, and 90.3% for COD, NO₃, TN, and TP) and bioenergy generation of 2.68 kWh, balancing environmental benefits with superior treatment efficiency. In contrast, the stand-alone MFC shows higher environmental burdens, primarily due to energy-intensive material requirements and fabrication processes. TEA results highlight CW as the most cost-effective solution (USD 627/m³), with CW–MFC emerging as a competitive alternative when considering environmental benefits and operational efficiencies (USD 718/m³). This study highlights the potential of hybrid systems, such as CW–MFC, to advance sustainable wastewater treatment technologies by minimizing environmental impacts and enhancing resource recovery, supporting their broader adoption in future water management strategies. Future research should focus on optimizing materials and energy use to improve scalability and feasibility.

Sustainability assessment of municipal solid waste management requires a holistic approach in evaluating the impacts of current technology and processes. In this study, the sustainability analysis of the Municipal Solid Waste (MSW) incineration plant in Baltimore city was performed to determine its environmental, economic, and social impacts. The city’s major waste-to-energy generation plant has benefitted the city of Baltimore since inception till date in terms of waste processing, resulting in electricity and steam production for more than 40,000 homes and over 200 businesses. The life cycle impact of the incineration plant was analyzed using the Simapro life cycle assessment (LCA) software with the Building for Environmental and Economic Sustainability (BEES) database for correlation. The results obtained upon analysis show larger values of Global Warming Potential and eutrophication potential as 6.46 × 10⁸ Gg of CO₂ equivalence and 2.27 × 10⁶ Gg N equivalence, respectively. These values resulted from the higher amount of fossil CO₂ and NOx emitted from the plant. The acidification potential of 1.66 × 10¹⁷ H⁺ mmole eq resulted from the SO₂ emitted by the incineration plant. The incineration plant exceeded the limitations set by the Environmental Protection Agency (EPA) on NOx (150 ppm), which is detrimental to the well-being of people as shown by this study. Installing an improved processing technology such as a Selected Catalytic Reactor (SCR) can drastically reduce the NOx emission to 45 ppm. Life Cycle Assessment was confirmed suitable in evaluating the environmental impacts of the MSW-to-energy treatment approach.

Excessive land application of poultry litter (PL) may lead to surface runoff of nitrogen (N) and phosphorus (P), which cause eutrophication, fish death, and water pollution that ultimately have negative effects on humans and animals. Increases in poultry production in the Delmarva Peninsula underscore the need for more efficient, cost-effective, and sustainable disposal technologies for processing PL instead of direct land application. The pyrolysis conversion process can potentially produce nutrient-rich poultry litter biochar (PLB), while the pyrolysis process can change the N and P to a more stable component, thus reducing its runoff. Pyrolysis also kills off any microorganisms that would otherwise trigger negative environmental health effects. This study is to apply an integrated method and investigate the effect of pyrolysis temperature (300 °C, 500 °C), poultry litter source (different feedstock composition), and bedding material mixture (10% pine shavings) on PLB qualities and quantities. Proximate and ultimate analysis showed PL sources and bedding material addition influenced the physicochemical properties of feedstock. The SEM and BET surface results indicate that pyrolysis temperature had a significant effect on changing the PLB morphology and structure, as well as the pH value (7.78 at 300 °C vs. 8.78 at 500 °C), extractable phosphorus (P) (18.73 ppm at 300 °C vs. 11.72 ppm at 500 °C), sulfur (S) (363 ppm at 300 °C vs. 344 ppm at 500 °C), and production yield of PLBs (47.65% at 300 °C vs. 60.62% at 500 °C). The results further suggest that adding a bedding material mixture (10% pine shavings) to PLs improved qualities by reducing the content of extractable P and S, as well as pH values of PLBs. This study also found the increment in both the pore volume and the area of Bethel Farm was higher than that of Sun Farm. Characterization and investigation of qualities and quantities of PLB using the integrated framework suggest that PL from Bethel Farm could produce better-quality PLB at a higher pyrolysis temperature and bedding material mixture to control N and P runoff problems.

Compared with the waste-to-heat and electricity-based hybrid refrigeration system, the innovative lab-scale refrigeration system integrated with the DC and AC cooling units that able to use solar and electricity as energy resources. Previous studies found that temperature control and uniform temperature distribution in refrigeration systems are both critical factors reducing vibrio growth on raw oysters and saving energy consumption. Therefore, this refrigeration system also equipped a specially designed divider and was used to test various air circulation strategies to achieve uniform temperature distribution in six individual compartments. The objective is to investigate and evaluate the effects of air circulation strategies and operating conditions on the cooling performance, including temperature distribution, standard deviation of compartment temperatures, and cooling time using a factorial design method. Results indicated the maximum temperature difference between the compartments was 8.9 ± 2.0 °C, 6.7 ± 2.0 °C, and 4.8 ± 2.0 °C in the scenarios of no air circulation, natural air circulation, and combined natural and forced air circulation, respectively. The interaction of fan location and fan direction showed a significant effect on the compartment temperatures while there was no significant effect on cooling time. A circulation fan on the lower part of the 12-volt section with an air supply from the 12- to 110-volt section was determined as the optimal condition to achieve relatively uniform temperature distribution. Refrigeration system also achieved a cooling temperature of 7.2 °C within 150 min to meet regulations. To that end, the innovative hybrid oyster refrigeration system will benefit oyster industries, as well as the aquaculture farmers in terms of complying with regulations and energy savings.

Increasing production of poultry litter, and its associated problems, stimulates the need for generating useful energy in an environmentally friendly and efficient energy system, such as the use of shell-and-tube heat exchangers (STHE) in a fluidized-bed combustion (FBC) system. A holistic approach which involves the integration of the First Law of Thermodynamics (FLT) and Second Law of Thermodynamics (SLT) is required for conducting effective assessment of an energy system. In this study, the STHE designed by the CAESECT research group, which was integrated into the lab-scale FBC, was investigated to determine the maximum available work performed by the system and account for the exergy loss due to irreversibility. The effects of varying operating parameters and configuration of the space heaters connected to the STHE for space heating purposes were investigated in order to improve the thermal efficiency of the poultry litter-to-energy conversion process. Exergy and energy analysis performed on the STHE using flue gas and water media showed higher efficiency (75–92%) obtained via energy analysis, but much lower efficiency (12–25%) was obtained when the ambient conditions were factored into the exergy analysis, thus indicating huge exergy loss to the surroundings. From the obtained experimental data coupled with the simulation on parallel arrangement of air heaters, it was observed that exergy loss increased with increasing flue gas flow rate from 46.8–57.6 kg/h and with increasing ambient temperature from 8.8 °C to 25 °C. To lower the cost of STHE during final design, a larger temperature difference between the hot and cold flue gas is needed throughout the exchanger, which further increases the exergetic loss while maintaining an energy balance. In addition, this study also found the optimal conditions to reduce exergy loss and improve energy efficiency of the designed STHE. This study shows the possibility to evaluate energy systems using integration of exergy and energy analysis.