Benchmarking and smart control in Finnish sewerage pumping stations

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Journal Title
Journal ISSN
Volume Title
Insinööritieteiden korkeakoulu | Master's thesis
Author
Date
2023-06-12
Department
Major/Subject
Mcode
Degree programme
Master's Programme in Water and Environmental Engineering (WAT)
Language
en
Pages
84 + 16
Series
Abstract
Sewerage system avoids flood and pollutants being discharged into the environment, which presents considerable economic, social, and environmental impacts. Due to the worldwide energy crisis and climate change from urbanization, the current network capacity and control will not be sufficient. Hence, we need better control for the pumping stations to satisfy future requirements. The goal of the work is to create an overall picture of the current Finnish sewerage systems and evaluate the effectiveness and applicability of smart control in reducing energy consumption and flooding. The study was conducted in two phases: benchmarking and smart control solutions. In the first phase, the performance of the wastewater system in general and pumping stations specifically in five water utilities (HS-Vesi Oy, Porvoon Vesi, Kurikkan Vesihuolto Oy, Kouvola Vesi, and Tuusulan Vesi) was analyzed with their hydraulic performance and flood-risk assessment, therefore pointing out the opportunities for improvement. Following this, several pumping station chains were selected for applying smart control. The second phase was to develop a suitable wet well’s level control algorithm based on two principles: variable speed drive and feedback PID controller. The results indicated that the infiltration rate of the Finnish sewerage network was on an average level and the energy efficiency was on a fair to poor level, according to studies from other countries and based on the assessment standards. Yet, there is an opportunity to apply energy-recover equipment in the future. When comparing the five studied sites, Kurikka and Porvoo had lower infiltration rates, while Kouvola and Hämeenlinna had higher energy efficiency. The proposed level control worked at its best during conditions that have high total inflows, in combination with more suitable pump selections. More thorough research should be done in the future on the energy-saving potential of using variable speed drives in combination with level control. The level control performance in overflow reduction was restricted to a definite level based on the network capacity. When the total network capacity has been utilized, additional storage is suggested to store the overflows.
Description
Supervisor
Vahala, Riku
Thesis advisor
Sunela, Markus
Keywords
sewer network, energ efficiency, overflows, level control, energy balance, pumping station
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Citation