The Effect of Biofilm Growth on Wall Shear Stress in Drinking Water PVC Pipes
Muthukrishna vellaisamy Kumarasamy, Phylicia Megan Maharaj
More details
Hide details
Civil Engineering Programme, School of Engineering, University of KwaZulu-Natal,
Durban 4041, South Africa
Submission date: 2015-05-02
Final revision date: 2015-06-18
Acceptance date: 2015-06-20
Publication date: 2015-11-27
Pol. J. Environ. Stud. 2015;24(6):2479–2483
Water quality in the distribution system depends on the operation and design of the system – including the treatment process. In addition to water quality, high energy costs and increasing demand require that the water supply infrastructure should function optimally. The change in roughness of pipe surface is common in a distribution system, which is influenced by factors such as tuberculation, sedimentation, and biofilm growth. Among these, biofilm growth is the focus of our study. One of the factors affecting biofilm growth is the velocity field of the fluid in contact with the microbial layer, or vice versa. Literature states that a high shear force will result in denser, stronger biofilms, while low shear forces result in a monolayer of biofilm cells. Most investigations focused on relating biofilm growth and variation of different factors such as disinfectants, pipe materials, water quality, etc. One aspect that affects the shear stress is the roughness of a solid surface over which the fluid flows. Investigation into the relationship between shear stress and biofilm growth was carried out with poly vinyl chloride pipe coupons attached to the bottom of the channel, where the biofilms were allowed to grow. Velocity components at different locations along the channel were measured by laser Doppler anemometer for further analysis. The results indicated that the shear stress only increased slightly with younger biofilm layers, and that further analysis is required with thicker and more mature biofilms.