scholarly journals Corrosion Characterization at Surface and Subsurface of Iron-Based Buried Water Pipelines

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5877
Author(s):  
Dessalegn Ahmed Yeshanew ◽  
Moera Gutu Jiru ◽  
Gulam Mohammed Sayeed Ahmed ◽  
Irfan Anjum Badruddin ◽  
Manzoore Elahi M. Soudagar ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Addis Ababa ◽  
Optical Microscope ◽  
Galvanized Steel ◽  
Uniform Corrosion ◽  
Corrosion Morphology ◽  
Pipe Surface ◽  
Pit Depth ◽  
Area And Volume

Water pipe surface deterioration is the result of continuous electrochemical reactions attacking the surface due to the interaction of the pipe surface with environments through the time function. The study presents corrosion characterization at the surface and sub-surface of damaged ductile iron pipe (DIP) and galvanized steel (GS) pipes which served for more than 40 and 20 years, respectively. The samples were obtained from Addis Ababa city water distribution system for the analysis of corrosion morphology patterns at different surface layers. Mountains 8.2 surface analysis software was utilized based on the ISO 25178-2 watershed segmentation method to investigate corrosion features of damaged pipe surface and to evaluate maximum pit depth, area, and volume in-situ condition. Based on the analysis maximum values of pit depth, area and volume were 380 μ m, 4000 μm2, and 200,000 μm3, respectively, after 25% loss of the original 8 mm thickness of DIP. Similarly, the pit depth of the GS pipe was 390 μm whereas the maximum pit area and volume are 4000 μm2 and 16,000 μm3, respectively. In addition, characterizations of new pipes were evaluated to study microstructures by using an optical microscope (OM), and a scanning electron microscope (SEM) was used to analyze corrosion morphologies. Based on the SEM analysis, cracks were observed at the sub-surface layer of the pipes. The results show that uniform corrosion attacked the external pipe surface whereas pitting corrosion damaged the subsurface of pipes. The output of this study will be utilized by water suppliers and industries to investigate corrosion phenomena at any damage stage.

scholarly journals Hydraulic Performance Analysis and Modeling of Water Supply Distribution System of Addis Ababa Science and Technology University, Ethiopia

2020 ◽  
Author(s):  
Chalchisa Milkecha ◽  
Habtamu Itefa
Keyword(s):  
Water Supply ◽  
Water Demand ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Addis Ababa ◽  
Science And Technology ◽  
Hydraulic Performance ◽  
Alternative Methods ◽  
The University

This study was conducted generally by aiming assessment of the hydraulic performance of water distribution systems of Addis Ababa Science and Technology University (AASTU). In line with the main objective, this study addressed, (1) pinpointing problems of existing water supply versus demand deficit (2) evaluating the hydraulic performance of water distribution system using water GEMS and (3) recommended alternative methods for improving water demand scenarios. The University’s water supply distribution network layout was a looped system and the flow of water derived by both gravity and pressurized system. The gravity flow served for the academic and administrative staffs whereas the pressurized system of the network fed the students dormitories, cafeteria’s etc. The study revealed the existence of unmet minimum pressure requirement around the student dormitories which accounts 25.64% below the country’s building code standard during the peak hour consumption. The result of the water demand projection showed an increment of 2.5 liter per capita demand (LPCD) in every five years. Hence, first, the university’s water demand was projected and then hydraulic parameters such as; pressure, head loss and velocity were modeled for both the existing and the improved water supply distribution. The finding of the study was recommended to the university’s water supply project and institutional development offices for its future modification and rehabilitation works.

scholarly journals In-Situ Monitoring and Analysis of the Pitting Corrosion of Carbon Steel by Acoustic Emission

2019 ◽  
Vol 9 (4) ◽  
pp. 706 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and corrosion morphology in-situ capturing using an optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with a scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After completion of the signal processing, including pre-treatment, shape preserving interpolation, and denoising, for raw AE waveforms, three types of AE signals were classified in the correlation diagrams of the new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

scholarly journals Modelling the potable water quality in a distribution network based on the hydraulic conditions

2020 ◽  
Author(s):  
Jani Tomperi
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Water Distribution ◽  
Potable Water ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Quality Model ◽  
Pipe Surface ◽  
Hydraulic Conditions ◽  
Potable Water Quality

Abstract. Abnormalities in hydraulic conditions inside a water distribution network are strongly related to the deterioration of potable water quality. Leaking pipes and valves, for instance, cause changes in water hydraulic conditions and may allow the entry of microbes to the distribution system. Flow and pressure shocks can detach soft deposits and biofilms from the pipe surface which is shown among others as the elevated concentrations of bacteria, metals and turbidity in water. On that account, monitoring the hydraulic conditions in a distribution network and utilizing this information in developing a predictive water quality model assists providing a sufficient amount of potable water with an appropriate quality for the consumers use. In this paper, the water quality at the end part of the district metered area is modelled based on only the water flow and pressure measurements along the distribution network. The developed model can be utilized in proactive operation as it is able to show the potable water quality hours in advance before it is discovered at the end part of the distribution network.

scholarly journals The Interaction between the Bulking Water and Pipe Surface and Their Correlations in Water Distribution System

2018 ◽  
Vol 7 (2) ◽  
pp. 83
Author(s):  
Ruilian Li ◽  
Ming-qing Feng ◽  
Xiao-hui Bai
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Tap Water ◽  
Close Relation ◽  
Quality Parameters ◽  
Iron Corrosion ◽  
Pipe Surface ◽  
Pipe Water

The pipelines corrosion can result discolor and particle increase in tap water and the complaints from the consumers. It also has the economic and hydraulic impacts for the replacement of broken pipes and fouling of corroded pipes. This paper aimed to investigate the effect of processed drinking water on metal pipe corrosion in water distribution system and the relations between the bulking water quality and pipe corrosion. It was found that there is a close relation between iron corrosion and water quality parameters in water distribution pipelines. It was shown that lower pH and alkalinity can increase the corrosion rate, while higher chlorides and sulfate may cause pitting corrosion. DOC in pipe water would be beneficial for microbial induced corrosion.

scholarly journals In-Situ Monitoring and Analyzing Pitting Corrosion of Carbon Steel by Acoustic Emission

2018 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and the corrosion morphology in-situ capturing using optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After the performing of signal processing including pre-treatment, shape preserving interpolation and denoising for raw AE waveforms, three types of AE signals can be classified in the correlation diagrams of new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

scholarly journals Dynamic response of biofilm to pipe surface and fluid velocity

2003 ◽  
Vol 47 (5) ◽  
pp. 57-59 ◽  
Author(s):  
T.E. Cloete ◽  
D. Westaard ◽  
S.J. van Vuuren
Keyword(s):  
Distribution System ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Fluid Velocity ◽  
Flow Conditions ◽  
Dapi Staining ◽  
Biofilm Growth ◽  
Pipe Surface ◽  
Viable Bacteria

Biofouling in pipelines is a function of the inner roughness of the specific piping material that is used in distribution systems and the concomitant biofilm formation. To test the effect of velocity on the growth of biofilm, a Roto-Scope was designed and built to imitate different materials and flow conditions in potable water distribution systems. Biofilm formation was monitored using DAPI staining and the total number of viable bacteria. Increased velocity in the system resulted in a specific detaching velocity, where the formation of biofilm was limited. Most of the time these detaching velocities were not the highest velocities tested. The range of detaching velocities was between ±3 m.s−1 and 4 m.s−1. A flow velocity within this range would thus be ideal for achieving reduced biofilm growth in a distribution system.

scholarly journals Determination of the corresponding roughness height in a WDS model containing old rough pipes

2019 ◽  
Vol 69 (3) ◽  
pp. 201-209 ◽  
Author(s):  
Ivar Annus ◽  
Anatoli Vassiljev ◽  
Nils Kändler ◽  
Katrin Kaur
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Pipe Wall ◽  
Field Studies ◽  
Quality Estimation ◽  
Pipe Surface ◽  
Computational Fluid Dynamics Cfd ◽  
The Mean

Abstract The aim of the paper was to determine the influence of irregular pipe wall roughness on the flow velocity in a water distribution system (WDS) containing old pipes. Field studies have shown that due to pipe wall build-up, the shape of the inner pipe surface can vary temporally and spatially. This will lead to unrealistic pipe roughness values when calibrating the WDS model using nominal pipe diameters. Therefore, in this study, three types of pipe wall build-up were investigated using EPANET2 and computational fluid dynamics (CFD) to estimate the velocity correction coefficients for EPANET2 calculations. It was shown that in old rough pipes, the mean velocities are higher than expected, indicating that in water quality estimation in a WDS, actual pipe diameters with reasonable roughness need to be defined.

Characteristics of pipe-scale in the pipes of an urban drinking water distribution system in eastern China

2015 ◽  
Vol 16 (3) ◽  
pp. 715-726 ◽  
Author(s):  
Jingqing Liu ◽  
Huanyu Chen ◽  
Qian Huang ◽  
Liping Lou ◽  
Baolan Hu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Drinking Water ◽  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Eastern China ◽  
Galvanized Steel ◽  
Drinking Water Distribution System ◽  
Drinking Water Distribution

Pipes that carry drinking water have gradually aged. Events occurring with increasing frequency, such as substandard water quality in residential taps, red water, and black water, reveal the deterioration of the chemical stability of a drinking water distribution system (DWDS). Pipes in the DWDS serving City S, located in eastern China, were sampled to analyze the concentration and distribution of pollutants in pipe-scale of pipes of different materials, ages and diameters, and the factors (such as materials, age, and diameter) influencing the accumulation of pollutants were also investigated. The quantity of pipe-scale in the most commonly used gray cast iron pipe and ductile cast iron pipe (DN150) was 151.5–195.0 g·m−1 and 7.1–29.4 g·m−1, respectively. The concentration of heavy metals in pipe-scale was positively correlated with the quantity of pipe-scale (R2 = 0.874); the sequence of concentration of metals was Fe > Al > Mn, Zn > Pb, Cu > Cr, Cd. Galvanized steel pipe, with the highest degree of corrosion, had the highest concentration of heavy metals in pipe-scale. The morphology and composition of pipe-scale were substantially influenced by pipe material and age. For example, in the oldest galvanized steel pipe-scale, there was not only a large number of iron compounds but also some zinc composite oxides. In addition to hydrocarbons produced by microbial metabolism, there were microalgae metabolites and exogenous contaminants such as polycyclic aromatic hydrocarbons (PAHs). The concentrations of microbial metabolites increased with increasing service time.

Contamination potential of drinking water distribution network biofilms

2004 ◽  
Vol 49 (11-12) ◽  
pp. 277-286 ◽  
Author(s):  
J. Wingender ◽  
H.-C. Flemming
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Galvanized Steel ◽  
Detection Methods ◽  
Coliform Bacteria ◽  
Plate Count ◽  
Drinking Water Distribution ◽  
Biofilm Development

Drinking water distribution system biofilms were investigated for the presence of hygienically relevant microorganisms. Early biofilm formation was evaluated in biofilm reactors on stainless steel, copper, polyvinyl chloride (PVC) and polyethylene coupons exposed to unchlorinated drinking water. After 12 to 18 months, a plateau phase of biofilm development was reached. Surface colonization on the materials ranged between 4 × 106 and 3 × 107 cells/cm2, with heterotrophic plate count (HPC) bacteria between 9 × 103 and 7 × 105 colony-forming units (cfu)/cm2. Established biofilms were investigated in 18 pipe sections (2 to 99 years old) cut out from distribution pipelines. Materials included cast iron, galvanized steel, cement and PVC. Colonization ranged from 4 × 105 to 2 × 108 cells/cm2, HPC levels varied between 101 and 2 × 105 cfu/cm2. No correlation was found between extent of colonization and age of the pipes. Using cultural detection methods, coliform bacteria were rarely found, while Escherichia coli, Pseudomonas aeruginosa and Legionella spp. were not detected in the biofilms. In regular operation, distribution system biofilms do not seem to be common habitats for pathogens. However, nutrient-leaching materials like rubber-coated valves were observed with massive biofilms which harboured coliform bacteria contaminating drinking water.

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