Analytical Study to Use the Excess Digester Gas of Wastewater Treatment Plants

Abstract

This study presents an analytical method that can be used to enhance the power production rate and the energy-saving at wastewater treatment plants. The digester used at wastewater treatment plants produce digester gas by anaerobic digestion, with which biofuel production can be achieved. Biofuels can be used to meet some of the energy requirements of the wastewater treatment facility through Combined Heat and Power (CHP) gas engines (co-generation). Using Micro Gas Turbine (MGT), a CHP technology can be introduced in Wastewater Treatment Plants (WWTPs). The combination of MGTs and absorption chillers is a promising technology as it produces electricity, heating, and cooling simultaneously. The study demonstrated how the waste heat of MGTs could be used to drive absorption chillers. In this analytical study, a detailed technical and economic analysis is provided on the tri-generation system, i.e., the integration of MGTs and absorption chillers driven by waste digester gas of the wastewater treatment plants. It can meet the heating and cooling demands of the plants, which promote the reduction of utility costs. The technology presented is also useful for other thermal energy users.

Study of Energy Saving Analysis for Different Industries

“…For a more fundamental understanding, the primary sector SIC code is included in parenthesis. Nonmetallic Minerals, Except Fuels ( 14), Food and Kindred Products (20), Lumber and Wood Products (24), Furniture and Fixtures (25), Paper and Allied Products (26), Printing and Publishing (27), Chemicals and Allied Products (28), Rubber and MISC. Plastic Products (30), Stone, Clay, Glass, and Concrete Products (32), Primary Metal Industries (33), Fabricated Metal Products (34), Industrial Machinery and Equipment (35), Electronic and Other Electric Equipment (36), Transportation equipment (37), Instruments and Related Products (38), Miscellaneous Manufacturing industries (39), and Electric, Gas, and Sanitary Services (49).…”

“…Industries with SIC of 34 and 49 achieved savings of 1,534,000 kWh and 1,430,000 kWh, respectively, while that with GJ energy SIC of 20 and 34 achieved savings of 10,200 GJ and 7,900 GJ, respectively. The authors studied the possibility of introducing CHP to wastewater treatment plants holding the SIC of 49 to help save energy, considering that WWTPs have potential savings in both kWh in an indirect way and GJ [24]. Another energy-saving opportunity in WWTPs was studied by introducing hydro turbines to generate power and evaluating the power output to determine energy savings [25].…”

Integration of renewable energy in wastewater treatment during COVID-19 pandemic: Challenges, opportunities, and progressive research trends

“…On the other hand, WWTPs using anaerobic digestion have lower chances of achieving thermal self-sufficiency than biogas combustion and heat recovery ( Duarte et al 2018 ). Technologically, there are three primary approaches for generating or recovering heat at wastewater treatment plants: (a) combustion of digester gas via cogeneration, application of in-sewer heat exchangers ( Nourin et al 2021 ), (b) external heat pumps for wastewater heat recovery ( Reiners et al 2021 ), and (c) use of solar thermal generation (Ver ma et al 2019 ). In addition to sewage sludge incineration, heat can also be generated ( Tarpani et al 2018 ).…”

Analysis of Energy Savings and CO2 Emission Reduction Contribution for Industrial Facilities in USA

“…Our team has been optimizing the energy generation by renewable resources such as wind turbines, hydro turbines, biomass, and solar energy to provide innovative solutions to the different industries [46][47][48][49][50]. The study's objective is to identify, evaluate, and recommend-through analyses of industrial plant operations-opportunities to conserve energy, minimize waste, and reduce the overall cost of operations.…”