جستجوی مقالات مرتبط با کلیدواژه "water stability indices" در نشریات گروه "پزشکی"

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. 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. 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. 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.

Corrosion and scaling are the main problems that water facilities still face with them. Corrosion can caused great financial losses and health damage to the system, and consumers. Blockages and pressure drop in the network are another disadvantage of scaling. The aim of present study was to determine the corrosive and scaling potential in drinking water resources of Shahrood city.
This crosses-sectional study was conducted over 4 seasons in 2013 years. 1104 samples were examined using Langelier (LSI), Rayznr (RSI), aggressive (AI) and Pokurious (PSI) indices to determine the corrosive and scaling potential in drinking water resources of Shahrood city. To compare the mean values of each indices, the results were analyzed using t-test.
The results indicate that the drinking water resources of Shahrood according to the Langelier index equals -1.03 with a standard deviation of 0.11, according to Rayznr index equals 9.72 with a standard deviation of 0.17, based on Aggressive index equals 12.10 with a standard deviation of 0.14, based on Pokurious index equals 9.59 with a standard deviation of 0.13 respectively. The difference between the mean values of the four studied seasons also were significant. P-value Comparison of four indices and obtained results showed that drinking water resources in Shahrood was corrosive, therefore, it is suggested that the city's water resources should constantly assessed and try adjusting the pH and control of other affecting factors on the corrosion such as chloride, dissolved oxygen and sulfate concentrations to reduce corrosion.

Corrosion and scaling in water distribution system are very important as a matter of financial and health issues. This study was carried out to evaluate the corrosion and scaling potential in the water distribution system of Torbat Heydariyeh city in 2012.
This cross- sectional/ descriptive study used cluster sampling in which the city was divided into 15 clusters. 6 subjects per each cluster (total 90 subjects) were selected via random sampling during 2012. Samples were analyzed through standard methods. To determine the corrosion and scaling potential, five indices including Langlier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI), Larson-Skold Index (LS) and Aggressive Index (AI) were studied.
Based on the results, Rayzner, Langelier, Pokurious, Larson-Skold Ratio and Aggressive indices are 7.72 (±0.2), 0.021 (±0.12), 7.65 (±0.3), 1.72(±0.45), and 12.05 (±0.12), respectively which indicate 40, 100, 100, 94, and 33 percent of water in distribution system is corrosive according to RSI, LSI, PSI, LS and AI indices.
Overall, water is slightly corrosive in distribution system of Torbat Heydariyeh city. Thus, it is recommended to perform measures such as pH, alkalinity, hardness adjustment to mitigate corrosion and corrosion by-products.