Energy Performance Analysis of Biogas-Fueled Combined Heat and Power (CHP) Production for Kaliti Wastewater Treatment Plant, replacing the existing Biogas Flare System and Recovering Energy
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Date
2025-05
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Addis Ababa University
Abstract
The Kaliti Wastewater Treatment Plant in Addis Ababa, Ethiopia, currently underutilizes biogas produced during wastewater treatment by flaring it off, the flare system can handle a maximum daily methane production of 13,000 Nm³, operating within a pressure range of 10-65 mbar and managing biogas flow rates between 40-600 Nm³/h. This inefficiency contributes to environmental pollution and missed opportunities for energy independence. The plant wastes valuable renewable energy by flaring biogas instead of capturing and utilizing it,. This thesis aims to investigate the feasibility of implementing a biogas-fueled combined heat and power (CHP) system at the Kaliti Wastewater Treatment Plant to address the underutilization of biogas and improve energy efficiency. The study involved data collection on biogas production rates, plant energy consumption, and biogas characteristics. A site assessment evaluated existing infrastructure and potential CHP system locations. A biogas CHP system was designed and modeled using collected data and industry benchmarks. Energy performance analysis assessed electricity generation and heat recovery potential, followed by sensitivity analysis to explore parameter variations. Biogas production at the plant exhibits notable seasonal fluctuations, likely influenced by varying biological processes within the digester. Implementing a CHP system offers a substantial improvement in energy utilization compared to flaring, with stable electric and thermal efficiencies across different biogas flow rates. The modeled CHP system demonstrates potential to generate significant electricity and thermal energy, reducing reliance on external energy sources and providing economic benefits through cost savings. The performance analysis of CHP system shows, the total electric energy production (1672 MWh/a) and total thermal energy production (1964 MWh/a). The implementation of a biogas-fueled CHP system presents a viable solution for enhancing energy efficiency, leveraging renewable energy sources, and achieving environmental sustainability at the Kaliti Wastewater Treatment Plant. Utilizing biogas for combined electricity and heat generation offers a sustainable approach to waste management while reducing environmental impact and operating costs. Investment in renewable energy technologies is crucial for long-term sustainability and resilience in wastewater treatment operations.
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Combined Heat and power (CHP), Energy Efficiency, Renewable Energy, Waste Water Treatment, Environmental Sustainability.