In a critical study recently published in the journal Environmental Research, scientists from the School of Environmental Science & Engineering at Tianjin University have reported groundbreaking discoveries related to the water quality in drinking water distribution systems (DWDS). These novel insights are particularly relevant to the global challenge of ensuring clean and safe drinking water in the face of fluctuating hydraulic conditions which are common in urban water supply networks. This news article will delve into the study’s findings, its implications, and the potential benefits of adapting water distribution practices to improve the quality of drinking water supply.

The Silent Guardian: Biofilm and Its Detachment in DWDS

The research led by Xin Changchun, along with an acclaimed team consisting of Soon-Thiam Khu, Tianzhi Wang, Xin Zuo, and Ying Zhang, focuses on the biofilm, a thin, slimy layer of microorganisms that adheres to the interior surfaces of water pipelines. While biofilms can act as a barrier against pathogen invasion, they also pose a major risk when they detach, leading to the pollution of water in DWDS.

The Trigger: Fluctuant Flow

The scientists zeroed in on how fluctuating flow velocity – which occurs due to varying consumer demand, maintenance activities, or system failures – affects the quality of water delivered to households and businesses. They meticulously analyzed the impact of these flow changes on the following quality indicators: turbidity, iron concentration, manganese concentration, total number of bacteria, biodegradable dissolved organic carbon (BDOC), bacterial community structure, and pathogenic genes in bacteria.

The Evidence: Flow Fluctuations Elevate Pollution Levels

Results indicated that fluctuant flow and especially instant reverse flow substantially increase the likelihood of biofilm detachment, leading to the pollution of water. During periods of flow fluctuation, turbidity levels were found to increase by 4.92% to 49.44%, and BDOC concentration rose by 5.68% to 53.99%. Furthermore, these flow variations have been linked to an increased potential for bacterial regrowth and a reduction in the biological stability of bulk water.

The Paradox: Low Flow Velocity and Pathogenic Genes

A rather paradoxical finding of the study is the expression of pathogenic functional genes during low flow velocity conditions. While initially, the water quality appears to be at its peak under low flow velocity, the conducive environment for pathogen gene expression presents a hidden threat.

The Long-Term Favor: High Flow Velocity for Sustained Water Quality

Compellingly, the study reveals that in the long term, water quality under high flow velocity conditions surpasses that of low or fluctuant flow velocities. Around seven days into the operation, the high flow velocity appears to better ensure water quality, suggesting that high flow could be a strategic element in maintaining cleaner water supply systems, provided the infrastructure can sustain it without leakage or breakage.

The Global Implication: A Quest for Stable Drinking Water Distribution

What this research underscores is the extent to which hydraulic conditions within our drinking water supply systems dictate the quality and safety of the water that reaches consumers. As cities grow and water demand becomes more sporadic, the need to understand and manage these conditions becomes ever more critical.

The Technology and Methodology

Highly sophisticated analytical methods such as microbial culture techniques, gene sequencing, and modern chemical analysis were employed to bring forth the insights shared in the findings. DOI: 10.1016/j.envres.2024.118142 stands as a testament to the rigorous scientific inquiry that supported the publication.


1. Changchun, X., Khu, S.-T., Wang, T., Zuo, X., & Zhang, Y. (2024). Effect of flow fluctuation on water pollution in drinking water distribution systems. Environmental Research, 246, 118142.

2. Environmental research journal. (2024). Retrieved from the ScienceDirect database.

3. Tianjin University School of Environmental Science & Engineering. (2024). Research publications.

4. The Engineering Research Center of City Intelligence and Digital Governance, Ministry of Education of the People’s Republic of China. (2024). Policy papers and research guidelines.

5. Elsevier Inc. (2024). Copyright information for Environmental Research, 246.

This impactful study not only adds a significant chapter to environmental research literature but also calls for a reevaluation of drinking water distribution practices in anticipation of countermeasures to sustain water quality.


1. Water Quality Distribution Systems
2. Biofilm Detachment Impact
3. Flow Fluctuation Water Pollution
4. Drinking Water Safety
5. Bacterial Regrowth Potential

The study authored by Changchun et al. unequivocally sets a new precedent in our understanding of drinking water quality management. It emphasizes the need for innovation in water distribution practices and the consideration of flow dynamics as a means of mitigating pollution and ensuring the provision of safe drinking water. Moving forward, this research has the potential not only to influence policy and infrastructure management but also to ignite further inquiries into how we harness and protect one of our most vital resources—clean water.