The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

Yun-tao Guan - One of the best experts on this subject based on the ideXlab platform.

  • Effect of biofilm on the corrosion and fouling of Cast Iron Pipe for water supply
    Environmental Sciences, 2009
    Co-Authors: Fei Teng, Yun-tao Guan, Sha-sha Li
    Abstract:

    : The crystalline phase and the element composition in the scales on Cast Iron Pipe for drinking water was identified with XRD and XPS respectively to investigate the effect of biofilm existence on the corrosion and fouling of Cast Iron Pipe. The total Iron concentration in the water phase was measured simultaneously. The results showed that on 0-7 d the total Iron concentration was higher in the water phase of the group with biofilm growth, but on 15-30 d it was higher in the water phase of the control without biofilm growth. The major peak of XRD patterns for the scales with biofilm growth was characterized as Fe oxide, while for the scales in the control it was always characterized as CaCO3. As presented by XPS atomic ratio, the Ca atomic percentage in the scales with biofilm growth was lower than that in the scales in the control, which might be contributed to the Ca2+ absorption by extracellular polymeric substances or Ca2+ consumption by microorganism growth. In comparison with that in the scales in the control, the Iron atomic percentage in the scales with biofilm growth was higher on 7 d, while lower after 7 d. It can be concluded that on 0-7 d the existence of biofilm could promote the corrosion of Cast Iron Pipe while inhibit corrosion after 7 d. The variance of major peak of XRD pattern and XPS atomic ratio indicated that biofilm had important effect on the configuration and composition of the scales of Cast Iron Pipe. The corrosion inhibition of biofilm thus provided a new pathway to control the corrosion of metal Pipes in drinking water distribution system.

  • effect of biofilm on Cast Iron Pipe corrosion in drinking water distribution system corrosion scales characterization and microbial community structure investigation
    Corrosion Science, 2008
    Co-Authors: Fei Teng, Yun-tao Guan
    Abstract:

    Effect of biofilm on corrosion scales of Cast Iron Pipe was studied with the biofilm community structure investigated by PCR-DGGE to give an explanation to MIC from the viewpoint of microbial phase. Corrosion scales were identified with XRD and XPS. It was demonstrated that biofilm can greatly affect element composition and crystalline phase of corrosion scales. Biofilm can accelerate corrosion in 7 d, but inhibit corrosion after 7 d, which was due to Iron bacteria and Iron reducing bacteria (IRB), respectively. DGGE fingerprinting gave a well explanation to this transition, which might be contributed to the change of biofilm microbial diversity.

Min Yang - One of the best experts on this subject based on the ideXlab platform.

  • effects of microbial redox cycling of Iron on Cast Iron Pipe corrosion in drinking water distribution systems
    Water Research, 2014
    Co-Authors: Haibo Wang, Chun Hu, Lili Zhang, Xiaoxiao Li, Yu Zhang, Min Yang
    Abstract:

    Abstract Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on Cast Iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and Iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced Iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of Iron, to enhance the precipitation of Iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including Iron-respiring bacteria and Rhizobium which captured Iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of Iron with associated microbial capture of Iron caused more compact corrosion scales formation and lower Iron release.

Jayantha Kodikara - One of the best experts on this subject based on the ideXlab platform.

  • numerical interpretation of pressurized corroded Cast Iron Pipe tests
    International Journal of Mechanical Sciences, 2017
    Co-Authors: Chunshun Zhang, Suranji Rathnayaka, Benjamin Shannon, Jian Ji, Jayantha Kodikara
    Abstract:

    Abstract Pitting/patch corrosion is a major and common cause of leaks and (or) bursts in Cast Iron (CI) Pipes that consist of over 50% of global Pipelines. The determination of the remaining life of a CI Pipe is a major challenge facing water utilities requiring an estimate of the impact of pitting corrosion on the degradation of structural Pipe capacity. This paper uses an efficient finite element analysis (FEA) to model the behaviour of large diameter CI Pipes with natural or simulated corrosion pits and patches. The test results were obtained through laboratory pressure testing. Laser scanning was used to develop three dimensional geometric models of Pipe specimens for direct use in the numerical modelling. The CI material was simulated by a non-linear hyperbolic elastic model (termed MHM-CI) recently developed by the authors for CI Pipe modelling. The numerical results showed that the proposed FEAs with the MHM-CI model are reasonably capable to predict the measured responses with increasing water pressure, importantly at the critical Pipe corrosion patches, such as hoop strains, initiation of leak and burst failures. The initiation of fracture was explained by material failure purely by tension, which can form a crack that could lead to water leakage. Final burst possibility was modelled by using a simplified fracture mechanics approach to determine the critical crack length for spontaneous fast fracture as in a burst. Our numerical findings suggest that the proposed simplified numerical approach may be used to determine whether a corroded Cast Iron Pipe would leak before break provided that the corrosion condition of the Pipe and the relevant material properties are available. However, the window of time for leak before break would require further testing since this would be governed by sub critical fracture growth subject to repetitive external and internal Pipe loadings.

  • Experimental evaluation of bursting capacity of corroded grey Cast Iron water Pipeline
    Structure and Infrastructure Engineering, 2017
    Co-Authors: Suranji Rathnayaka, Benjamin Shannon, Dilan Robert, Jayantha Kodikara
    Abstract:

    AbstractCast Iron was used in the water industry prior to 1970 and a large number of Cast Iron Pipes still remain as trunk mains. These Pipes have been subjected to different levels of corrosion and variety of loading conditions. This leads Cast Iron Pipes to fail in the field without prior warning. Water utilities are seeking solutions to optimise Cast Iron Pipe renewal and rehabilitation programs for critical water mains (diameter ≥ 300 mm). A new experimental set-up has been developed at Monash University in order to perform burst testing of large diameter Cast Iron Pipes (diameter ≥ 300 mm). A section of Cast Iron Pipe, extracted during maintenance in Sydney, was laser scanned to determine the remaining thickness of the Pipe (minimum of 7–8 mm at the most critical patches). Although the Pipe was pressurised to 3.6 MPa, catastrophic failure did not occur. Water leakage from the two critically corroded patches was observed at around 3.25–3.45 MPa internal pressure. Strain results on the outer Pipe surfa...

Fei Teng - One of the best experts on this subject based on the ideXlab platform.

  • Effect of biofilm on the corrosion and fouling of Cast Iron Pipe for water supply
    Environmental Sciences, 2009
    Co-Authors: Fei Teng, Yun-tao Guan, Sha-sha Li
    Abstract:

    : The crystalline phase and the element composition in the scales on Cast Iron Pipe for drinking water was identified with XRD and XPS respectively to investigate the effect of biofilm existence on the corrosion and fouling of Cast Iron Pipe. The total Iron concentration in the water phase was measured simultaneously. The results showed that on 0-7 d the total Iron concentration was higher in the water phase of the group with biofilm growth, but on 15-30 d it was higher in the water phase of the control without biofilm growth. The major peak of XRD patterns for the scales with biofilm growth was characterized as Fe oxide, while for the scales in the control it was always characterized as CaCO3. As presented by XPS atomic ratio, the Ca atomic percentage in the scales with biofilm growth was lower than that in the scales in the control, which might be contributed to the Ca2+ absorption by extracellular polymeric substances or Ca2+ consumption by microorganism growth. In comparison with that in the scales in the control, the Iron atomic percentage in the scales with biofilm growth was higher on 7 d, while lower after 7 d. It can be concluded that on 0-7 d the existence of biofilm could promote the corrosion of Cast Iron Pipe while inhibit corrosion after 7 d. The variance of major peak of XRD pattern and XPS atomic ratio indicated that biofilm had important effect on the configuration and composition of the scales of Cast Iron Pipe. The corrosion inhibition of biofilm thus provided a new pathway to control the corrosion of metal Pipes in drinking water distribution system.

  • effect of biofilm on Cast Iron Pipe corrosion in drinking water distribution system corrosion scales characterization and microbial community structure investigation
    Corrosion Science, 2008
    Co-Authors: Fei Teng, Yun-tao Guan
    Abstract:

    Effect of biofilm on corrosion scales of Cast Iron Pipe was studied with the biofilm community structure investigated by PCR-DGGE to give an explanation to MIC from the viewpoint of microbial phase. Corrosion scales were identified with XRD and XPS. It was demonstrated that biofilm can greatly affect element composition and crystalline phase of corrosion scales. Biofilm can accelerate corrosion in 7 d, but inhibit corrosion after 7 d, which was due to Iron bacteria and Iron reducing bacteria (IRB), respectively. DGGE fingerprinting gave a well explanation to this transition, which might be contributed to the change of biofilm microbial diversity.

Waltraud M Kriven - One of the best experts on this subject based on the ideXlab platform.

  • Iron release from corroded unlined Cast Iron Pipe
    Journal American Water Works Association, 2003
    Co-Authors: P Sarin, Vernon L Snoeyink, Jonathan A Clement, Waltraud M Kriven
    Abstract:

    One goal of drinking water treatment is to minimize Iron uptake from distribution systems in which old, corroded Iron and steel Pipes are used. This research evaluated the effects of changes in pH and alkalinity and the use of orthophosphates to minimize Iron release. A pilot Pipe-loop system was constructed using 100-year-old unlined Cast-Iron Pipes. The composition and structure of the corrosion scales were characterized, and Iron release was investigated for various water quality conditions. Results showed that Iron release could be reduced over time by maintaining a stable water quality. When the pH of water was raised to 9.5, Iron release during an 8-h stagnation period decreased from >1.5 mg/L to <0.3 mg/L within 6-8 months. Comparable results were obtained when an orthophosphate concentration of 3.0 mg/L as PO 4 was maintained in the influent to the Pipes. Iron release was found to be sensitive and complementary to changes in the alkalinity of water.

  • Iron release from corroded, unlined Cast-Iron Pipe
    Journal American Water Works Association, 2003
    Co-Authors: P Sarin, Vernon L Snoeyink, Jonathan A Clement, Waltraud M Kriven
    Abstract:

    One goal of drinking water treatment is to minimize Iron uptake from distribution systems in which old, corroded Iron and steel Pipes are used. This research evaluated the effects of changes in pH and alkalinity and the use of orthophosphates to minimize Iron release. A pilot Pipe-loop system was constructed using 100-year-old unlined Cast-Iron Pipes. The composition and structure of the corrosion scales were characterized, and Iron release was investigated for various water quality conditions. Results showed that Iron release could be reduced over time by maintaining a stable water quality. When the pH of water was raised to 9.5, Iron release during an 8-h stagnation period decreased from >1.5 mg/L to