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Showing 2 results for Corrosion
Analysis of Water Corrosion Tendency in Water Supply System Using Qualitative Indices and Calcium Carbonate Precipitation Potential index
R Nabizadeh Nodehi, Ar Mesdaghinia, S Nasseri, M Hadi, H Soleimani, P Bahmani,
Volume 9, Issue 4 (3-2017)
Abstract

Background and Objective: Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.

Materials and Methods: The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.

Results: The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.

Conclusion: The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.


Corrosion or scaling tendency and trend for water resources in rural areas of Kashan
M Hadi, Z Aboosaedi, H Pasalari,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Scaling and corrosion both are destructive to materials (usually metals) in water supply systems. A dataset (from 2002 to 2013) of groundwater resources (including springs, qanats, deep wells and semi-deep wells) were examined for water tendency to corrosion or scaling in rural regions of Kashan, a city in Isfahan, central Iran.
Materials and Methods: Water quality parameters including pH, temperature, Ca (mg/L), CO32- (mg/L), HCO3-(mg/L) and TDS (mg/L) were used to estimate water stability indices. Value of qualitative indices including Langelier (LSI), Ryznar (RSI), Puckorius (PSI) and trend of Calcium Carbonate Precipitation Potential (CCPP) as a quantitative index were calculated and analyzed for all water resources.
Results: Mean of LSI, RSI and PSI for all water resources were estimated to be 0.41±0.02, 6.39 ± 0.03, and 7.40±0.02, respectively. The CCPP value found to be 17.23±3.16, 15.66±1.38, 41.23±11.22, and 23.15±4.46 mg/L for springs, qanats, deep wells and semi-deep wells, respectively. The CCPP index was significantly increased from 2002 to 2013, with an average of 1.6 units per year.
Conclusion: A significant scaling tendency was observed. This tendency in decreasing order was observed in deep wells, semi-deep wells, springs and qanats. The estimated CaCO3 scale weight per cubic meter of water was 21 g on average, which may be problematic for water distribution systems. Water withdrawal management and reduction in TDS of water resources, perhaps through decrease in agricultural drainage, can be effective to reduce the scaling tendency.   
 

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