Discussion: The effect of pH adjustment on the internal corrosion rate of residential cast-iron and copper water distribution pipes

1988 ◽  
Vol 15 (6) ◽  
pp. 1085-1085
Author(s):  
John Bell
Keyword(s):  
Cast Iron ◽  
Corrosion Rate ◽  
Water Distribution ◽  
Internal Corrosion ◽  
Effect Of Ph ◽  
Ph Adjustment ◽  
Copper Water

The effect of pH adjustment on the internal corrosion rate of residential cast-iron and copper water distribution pipes

1988 ◽  
Vol 15 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Louise Millette ◽  
Donald S. Mavinic
Keyword(s):  
Cast Iron ◽  
Water Distribution ◽  
Copper Corrosion ◽  
Iron Corrosion ◽  
Internal Corrosion ◽  
Ph Adjustment ◽  
Water Pipes ◽  
Corrosion Rates ◽  
Copper Water ◽  
System Pressure

The Greater Vancouver Regional District distributes drinking water that displays several attributes of an aggressive water: low pH, low alkalinity, and high dissolved oxygen. A study, consisting of two experimental sessions, was conducted at the University of British Columbia to examine the effects of pH adjustment on internal corrosion of residential cast-iron and copper water distribution pipes.Because of its aggressive nature, this water accelerates the corrosion of water pipes, which not only increases maintenance costs, but also encourages high levels of metal in the water. This last finding was confirmed by a preliminary survey wherein, after one month's sampling of six dwellings, it was found that the recommended maximum level of 1.0 mg/L was exceeded in 67% of the morning cold water first-flush samples.Adjustment of pH with hydrated lime, Ca(OH)2, was used for corrosion control. Cast-iron and copper samples were exposed to pH-adjusted water for varying lengths of time, in two flow-through experimental systems (gravity-fed and system-pressure-fed).Although the corrosion rates were different for the two experimental sessions, analysis of the pH-related corrosion rates variation led to the same two findings. The corrosion rates of cast iron were 10 times those of copper; the increased pH enhanced these cast-iron corrosion rates by approximately 15%. However, a pH increase reduced copper corrosion by as much as 68%. The effects of increased pressure on corrosion were different for both metals; a higher pressure greatly enhanced cast-iron corrosion but had little effect on copper corrosion. Key words: aggressive water, cast iron, corrosion, copper, lime, pH adjustment, water pipes.

Predicting the effect of water quality on water distribution cast iron and steel pipes using two novel indices

2017 ◽  
Vol 18 (2) ◽  
pp. 524-538
Author(s):  
Marc Philibert ◽  
Sofia Mendaza ◽  
Flavia Zraick ◽  
Benjamin Rabaud
Keyword(s):  
Cast Iron ◽  
Corrosion Rate ◽  
Water Distribution ◽  
Iron Particle ◽  
Distribution Networks ◽  
Pilot Scale ◽  
Internal Corrosion ◽  
Iron And Steel ◽  
Particle Release ◽  
Steel Pipes

Abstract The internal corrosion of cast iron and steel pipes is one of the main issues that drinking water distribution operators are facing. This study evaluated the relevance of 10 known corrosion indices according to their estimate of corrosion rate and iron particle release for 20 different water qualities. Pilot-scale contact trials were run over 45 days using cast iron and steel coupons. Corrosion rate was measured by coupon weight-loss and by an online linear polarization rate probe. Particle release was monitored by an online turbidimeter. The results showed that none of the indices properly predicted the level of risk associated with each water and that corrosion and particle release were not correlated. Two novel indices were developed to predict the corrosion and particle release risks independently of each other. The corrosion index showed a strong linear correlation with the corrosion rate of cast iron and slightly less reliable results for steel. The Particle Emission Index presented good correlation with turbidity in waters following contact with cast iron. These two indices thus showed interesting potential as tools to limit internal corrosion risks for metal pipes in water distribution networks.

Water treatment to reduce internal corrosion in the drinking water distribution system in Oslo

2001 ◽  
Vol 1 (3) ◽  
pp. 91-96 ◽  
Author(s):  
L.J. Hem ◽  
E.A. Vik ◽  
A. Bjørnson-Langen
Keyword(s):  
Water Treatment ◽  
Corrosion Rate ◽  
Distribution System ◽  
Water Distribution ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Corrosion Monitoring ◽  
Copper Corrosion ◽  
Iron Corrosion ◽  
Internal Corrosion

In 1995 the new Skullerud water treatment plant was put into operation. The new water treatment includes colour removal and corrosion control with an increase of pH, alkalinity and calcium concentration in addition to the old treatment, which included straining and chlorination only. Comparative measurements of internal corrosion were conducted before and after the installation of the new treatment plant. The effect of the new water treatment on the internal corrosion was approximately a 20% reduction in iron corrosion and a 70% reduction in copper corrosion. The heavy metals content in standing water was reduced by approximately 90%. A separate internal corrosion monitoring programme was conducted, studying the effects of other water qualities on the internal corrosion rate. Corrosion coupons were exposed to the different water qualities for nine months. The results showed that the best protection of iron was achieved with water supersaturated with calcium carbonate. Neither a high content of free carbon dioxide or the use of the corrosion inhibitor sodium silicate significantly reduced the iron corrosion rate compared to the present treated water quality. The copper corrosion rate was mainly related to the pH in the water.

Corrosion rate and scale of cast iron in water distribution systems

2016 ◽  
Vol 22 (6) ◽  
pp. 516-524 ◽  
Author(s):  
Hao Guo ◽  
Yimei Tian ◽  
Haolin Chen ◽  
Yufen Fu ◽  
Xingfei Liu
Keyword(s):  
Cast Iron ◽  
Corrosion Rate ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems

scholarly journals Effects of disinfectant and biofilm on the corrosion of cast iron pipes in a reclaimed water distribution system

2012 ◽  
Vol 46 (4) ◽  
pp. 1070-1078 ◽  
Author(s):  
Haibo Wang ◽  
Chun Hu ◽  
Xuexiang Hu ◽  
Min Yang ◽  
Jiuhui Qu
Keyword(s):  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Reclaimed Water

Internal Corrosion Direct Assessment for Pipelines Carrying Wet Gas - Methodology

2004 ◽  
Author(s):  
Oliver Moghissi ◽  
Deanna Burwell ◽  
Rick Eckert ◽  
Jose Vera ◽  
Narasi Sridhar ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Flow Regimes ◽  
Distribution Model ◽  
Liquid Volume ◽  
Internal Corrosion ◽  
Integrity Verification ◽  
Direct Assessment ◽  
Wet Gas ◽  
Pipeline Segment ◽  
Flow Effects

An Internal Corrosion Direct Assessment methodology is proposed for wet gas pipelines (WG-ICDA). Wet gas systems (i.e., those normally containing liquids) include storage and gathering systems with large gas-to-liquid volume ratios. Wet gas systems are not well represented by ICDA for normally dry gas, and existing corrosion models applied to wet gas systems are not sufficiently targeted at integrity verification. The essential focus of WG-ICDA compared to other internal corrosion models is the discrimination of conditions along the length of a pipeline so that possible local integrity threats with respect to internal corrosion are identified and mitigated. The basis of WG-ICDA is to prioritize locations along a pipeline segment by factors of traditional corrosion rate, flow effects, and other influencing factors. Corrosion rate depends on gas quality, liquid chemistry, pressure, and temperature. The corrosion rate can be normalized because WG-ICDA as integrity verification only concerns itself with corrosion distribution (i.e., the location along a pipeline segment where corrosion is more severe than other locations). Flow effects include possible flow regimes and the presence of water from condensation (at locations of heat loss). Expected possible flow regimes are stratified, slugging, and annular. The final term captures other factors influencing corrosion rate distribution. These factors include corrosion inhibition (batch and continuous, solubility and dispersibility in hydrocarbon and aqueous phases), biocide treatments, hydrocarbon condensates (including emulsion characteristics), maintenance pigging, bacteria, solids/scale, and other products. WG-ICDA follows the same four-step process as all other Direct Assessment (DA) methods: 1) Pre-Assessment: Data is collected, a feasibility analysis is performed, and the pipeline segment is divided into regions. 2) Indirect Inspections: Measurements are taken or calculations are performed to prioritize locations along a particular pipeline segment for susceptibility to corrosion. For WG-ICDA, the factors contributing to the distribution of corrosion will be included and an initial assumption about corrosion distribution will be made. WG-ICDA is sufficiently flexible to allow the use of existing wet gas models within the framework of the overall process. 3) Direct (or Detailed) Examinations: The pipe is excavated and examined at locations prioritized to have the highest likelihood of corrosion. The examination must have sufficient detail to determine the existence, extent, and severity of corrosion. Examination of the internal surface of a pipe can involve non-destructive examination methods sufficient to identify and characterize internal defects. 4) Post-Assessment: Analysis of the indirect and direct examination data is performed to determine overall pipeline integrity, prioritize repairs, and set the interval for the next assessment. If the results of excavations do not match the original assumption, the corrosion distribution model will be updated to guide the next excavations (i.e., the operator returns to step 2).

scholarly journals Investigation of the effect of pH adjustment on the stability of nanofluid

2018 ◽  
Author(s):  
Sadik Umar ◽  
Fauziah Sulaiman ◽  
Nurhayati Abdullah ◽  
Saiful Najmee Mohamad
Keyword(s):  
Effect Of Ph ◽  
Ph Adjustment ◽  
The Stability
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