Investigating the Impact of Key Factors on the Dynamics of Material Accumulation and Re-Suspension in Drinking Water Distribution Systems
Loading...
Authors
Dunn, Susannah R. M.
Date
2024-05-01
Type
thesis
Language
eng
Keyword
Biofilms , Loose Deposit , Shear stress , Unidirectional Flushing (UDF) , Drinking water distribution system (DWDS) , Material mobilization rate (MMR) , Aluminum , Arsenic , Iron , Manganese
Alternative Title
Abstract
Providing safe and aesthetically pleasing drinking water continues to be a significant challenge for utilities. The purpose of this study was to evaluate the role that various operational and systemic characteristics play on the accumulation and re-suspension of biofilm and loose deposits in drinking water distribution systems. By investigating the interaction between shear stress and microbiological dynamics within a complex water distribution system, the research demonstrated the multifaceted impact of flow dynamics and the introduction of Mn(II) and Fe(III) on biofilm growth. It was revealed that shear stress exerts significant influence on bacterial growth in both bulk water and biofilm. A pattern of rapid growth, stabilization, and fluctuation in bulk water was observed, contrasted with minimal initial biofilm activity that transforms into rapid growth after an incubation period of approximately 28 days. Notably, higher shear stresses were found to promote enhanced microbial activity and biofilm growth, with specific bacterial genera exhibiting differential tolerance to elevated shear stress levels. Additionally, the study unveiled the impact of introducing iron(III) chloride and manganese sulfate on pH levels, biofilm activity, and metal deposition. Addressing the challenge of water discolouration and customer complaints associated with drinking water at the tap, the study also explored the mobilization dynamics of particulate material in operational distribution networks throughout unidirectional flushing. Notably, the highest mobilization rates were recorded within the initial 6 minutes of flushing, with specific shear stress values influencing the mobilization of individual elements. Aluminum and arsenic mobilization peaked at a shear stress of 7.5 Pa, while iron and manganese detachment exhibited varying responses to different shear stress levels. Biofilm detachment proved more resistant, with higher mobilization rates observed at greater shear stresses and later stages of flushing. The data also indicated that older pipes, particularly those comprising cast iron or a combination of cast iron and polymer-lined cast iron, exhibited higher material mobilization rates. The findings contribute to a deeper understanding of system dynamics, biofilm development, and water quality management, offering valuable insights for enhancing distribution system maintenance practices and ensuring the delivery of safe and aesthetically pleasing drinking water to consumers.
Description
Citation
Publisher
License
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NoDerivatives 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NoDerivatives 4.0 International