Author(s): Hossein Alaei Kakhki; Margherita Evangelisti; Marco Maglionico; Vittorio Di Federico

Linked Author(s): Marco Maglionico, Vittorio Di Federico

Keywords: Sewer; Modeling; Wastewater temperature; Heat transfer; Heat recovery

Abstract: Raw sewage contains a substantial quantity of energy that may be collected and utilized. This is accomplished by installing a heat pump and heat exchanger in the sewer system. It is necessary to quantify the changes in wastewater temperature along the flow path in the sewer system to identify the best location for the installation of devices for wastewater heat recovery and to calculate how much heat can be recovered without adversely affecting wastewater treatment. Heat transfer phenomena in sewers depends on the hydraulics of sewer pipes, on the thermal transfer between wastewater and in-sewer air, between wastewater and the pipe surface and also between the pipe surface and the surrounding soil. The purpose of this study is to present a simple model requiring minimal in-situ measurement of the hydraulic and thermal parameters of wastewater. After selecting the appropriate models for hydraulics and heat transfer based on physical considerations and prior research, a three-dimensional steady-state model was constructed using COMSOL Multiphysics; the most relevant input parameters were determined by performing a literature review. Comparing the outcomes of the model to those of TEMPEST, which is software for modeling the wastewater temperature in sewer conduit, and measured data, it was discovered that this model may produce satisfactory results with fewer parameters and measurements than TEMPEST. This model can become more precise as more information is gathered about the effluent, in-sewer air, sewer conduit, and soil surrounding the sewer system.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1248-cd

Year: 2023