Langelier Saturation Research Articles

Physico-chemical quality of tap water in an urban environment: The case of the Massengo district, arrondissement n°9 Djiri, Brazzaville

The drinking water supply in the Massengo Soprogi district in Brazzaville's Djiri 9 arrondissement is provided by the Djiri river, whose mineralization dictates that of the water in the distribution network. Tap water in this district was analyzed for various parameters in order to understand the acquisition of mineralization. The physico-chemical analysis of these water samples showed that the water has very little mineralization, and is not very hard due to the geological nature of the Djiri riverbed (sandy soil). The pH values in the wet and dry seasons give the water a weakly acidic nature and, taking into account the concentration of bicarbonate ions, a low level of complete alkalinity. The geochemical processes responsible for this mineralization are mainly: water-rock interaction and ion exchange, and silicate dissolution. The geochemical methods used were the Gibbs diagram and the calculation of a few characteristic ionic ratios. Tap water has a strong aggressive and corrosive tendency, as revealed by Langelier's saturation index and Ryznar's stability index.

Assessment of Corrosion and Scale forming Potential of Groundwater Resources: Case Study of Dire Dawa City, Ethiopia

Almost 100% of the water supply of Dire Dawa City is from groundwater (including boreholes, dug wells, and springs). Recently, groundwater cause corrosion and scale problems to water distribution systems due to its content of dissolved ions that can cause public health and economic issues. The present paper investigates the corrosion and scale-forming potential of the groundwater in the city and visualizes it with mapping. Spectrophotometer, EDTA/Acid titration with calculation methods were used for water quality parameters analysis. GW Chart Calibration plot applied for the Piper diagram to categorizes the water types. Langelier saturation (LSI), Ryznar (RSI), aggressive (AI), Puckorius Scale (PSI), and Larson-Skold (LRI) indices were manipulated with Excel ® and visualized their spatial distribution using ArcGIS 10®. The mean values of LSI, RSI, PSI, AI, and LRI obtained were 0.29 ± 0.28, 6.4 ± 0.5, 5.10 ± 0.48, 12.20 ± 0.24, and 1.4±1.57 respectively. LSI and RSI results indicate moderate to low scale-forming tendency of groundwater in most parts except the northeastern part with corrosive groundwater. Based on the AI value, the groundwater ranges low corrosion in almost all zones except the edge of the northeast and northwest region. PSI indicated the water tends to form salt-scale at a medium rate. The LSI results showed that chloride and sulphate are unlikely to interfere with the formation of protecting film except in northwestern and northeastern regions where localized corrosion might occur. In conclusion, in almost all distribution system of the city is affected by calcium carbonate scale formation. The groundwater in the northwest and northeast resulted in localized corrosion because of relatively high contents of chlorides and sulphates.

Evaluation of corrosion and scaling potential in rural water distribution network of Urmia, Iran

Water quality entering the drinking water distribution network often provides requirements for corrosion and scaling in rural areas due to the lack of suitable treatment methods. It leads to pipe clogging, reducing longevity of the equipment, and health problems caused by dissolved compounds in the water. The present study aims to evaluate the corrosion and scaling potential in water distribution networks of four villages located in different geographical locations of Urmia, Iran. In this descriptive cross-sectional study, 36 samples of water entering the villages of Dizaj-e Siavosh, Dolama, Gogtapeh, and Band distribution networks were analyzed according to standard methods for water and wastewater examinations. The corrosion and scaling potential were evaluated based on Ryznar stability (RSI), Langelier saturation (LSI), Puckorius scaling (PSI), and Larson–Skold (LRI) indices after determination of pH, total dissolved solids, sulfate, alkalinity, calcium hardness, and chloride. The results indicated that the values of LSI, RSI, PSI, and LRI indices were −1.94, 12.05, 12.20, and 0.68 for Gogtapeh water supply; −2.22, 12.72, 13.6, and 0.4 for Dizaj-e Siavosh water supply; −2.03, 12.1, 12.06, and 0.3 for Band water supply; and finally −2.09, 12.30, 12.59, and 0.29 for Dolama water supply, respectivly. Therefore, the water entering Gogtapeh distribution system has a tendency to scaling based on the LRI as an only appropriate index for the corrosion and scaling potential in this village. However, the water entering Dizaj-e Siavosh, Dolama, and Band distribution networks are highly corrosive based on the LSI, RSI, and PSI indices. The concordance between the analysis of chemical water quality and national standards could not be sufficient to confirm the water quality balance in terms of corrosion and scaling potential.

Study of Screening Reverse Osmosis Menmbrane Anti-Scaltants by Drainage Gradient Method

The aim of this paper is to elucidate the drainage gradient method's feasibility in evaluating and screening anti-scaltants. Nine different anti-scalants were selected as research object, the results show that KCa、KJD、pH and Langelier's saturation index (LSI) can be used as indicators and KJD、pH are more sutible indicators.with the relative standard deviations (RSD) of repeated experiments were from 0.24% to 3.04%, the drainage gradient method has good repeatability.

Major ion chemistry of the ground water at the Khoda Village, Ghaziabad, India

The ground water quality in and around the Khoda village, Ghaziabad, India, has been evaluated for sustainability and its suitability for drinking, domestic and irrigation purposes. A total of 184 ground water samples were collected from India Mark II hand-pumps during pre-monsoon (March 2011) and post-monsoon (October 2010) periods, respectively. All the samples were analyzed for 29 physicochemical water quality parameters. According to the Soltan’s classification, the majority of the samples were normal sulfate, normal bicarbonate and normal chloride types, respectively, during pre- and post-monsoon seasons. Base-exchange, meteoric genesis, Langelier saturation and Ryznar stability indices were also estimated. The total ionic dominance (meq/L) pattern follows the order Na+ > HCO3− > Cl− > Mg2+ > SO42− > Ca2+. Piper trilinear and Chadha’s rectangular diagrams indicated that alkali metals (Na+ + K+) exceed alkaline earth metals (Ca2+ + Mg2+) and anions of strong acids (SO42− + Cl−) dominate over anions of weak acids (HCO3− + CO3−), suggesting that this water is of the Na+ − Cl− and Na2SO4 types. Ground water suitability for irrigation was assessed using electrical conductivity and percent sodium, the US Salinity Laboratory’s diagram, residual sodium carbonate (RSC), salinity index, chlorinity index, sodicity index, Kelly’s Index and magnesium hazard.

The use of the drainage gradient method for evaluating reverse osmosis membrane anti-scalants

This paper describes the use of the drainage gradient method for assessing the relative inhibitory effectiveness of various reverse osmosis (RO) anti-scalants. Five different anti-scalants were selected for the examination of the drainage gradient method's feasibility for evaluating their relative inhibitory effectiveness. The results show that pH, ΔKCa (increase in cycles of concentration) and Langelier's saturation index (LSI) can be used as indicators and that ΔKCa is the most suitable indicator. The sensitivities of the three indicators from greatest to least are: ΔKCa>LSI≫pH, with relative standard deviations (RSD) which are 38.39%, 14.22%, and 1.45%, respectively. The order of the scale suppression effectiveness of the five tested anti-scalants, based on the three judgment indicators, is D>E>B>C>A.

Evaluation of Groundwater Quality in Northern Indo-Gangetic Alluvium Region

The northern Indo-Gangetic alluvium region is known for intensive agricultural and industrial activities. Groundwater is the main source used for drinking, irrigation and industrial purposes in this region. Groundwater quality assessment is an essential component for its safer use. Thus, the measurements on various water quality parameters were carried out on surface water and groundwater samples of dug wells, bore wells and hand pumps at different sites spread over an area of about 2150 km(2). Influence of soil on hydrochemistry of groundwater was investigated through analyzing soil characteristics at selected sites in the region. Water quality classification was investigated through calculating the base-exchange, meteoric genesis, Langelier saturation and Ryznar stability indices. Groundwater sources were evaluated according to various criteria for their drinking and domestic, irrigation (salinity, chlorinity and sodicity), and industrial (saturation index) uses. Soil-water interactions and impact on groundwater quality was evaluated using ion flux coefficient (cf). Results of this study show that the groundwater in the study region is mainly of Na-HCO(3) and shallow meteoric water percolation type. Low cf values observed for NO(3), PO(4), Ca and metals indicate their lower mobility from soil matrix to groundwater. About 4-19% of the groundwater samples showed levels of TDS, hardness, alkalinity, Cl, F, SO(4), Ca, Mn, Pb, Cr and Fe above their respective permissible limits. Majority of samples violating the drinking water guidelines belong to shallow depth aquifer. Correlations between various parameters lead to interpretation of the results of analysis and suggesting the ionic species present in the groundwater sources. Contamination of some groundwater aquifers with F, Pb and Cr indicates natural and anthropogenic influences.

Scaling in domestic heating equipment: getting to know a complex phenomenon

Excessive scaling is one of the main nuisances in relation to the use of drinking water. Ever more water companies try to minimise scaling. Although scaling is an old problem, prediction of scaling has been proven to be very tricky. Traditionally, the (Langelier) Saturation Index is used to evaluate scaling properties of drinking water. From experience it is well known that this parameter is not suitable for proper prediction. New parameters have been developed and standardised for scaling prediction, namely the Calcium Carbonate Precipitation Potential, calculated at a temperature of 90 degrees C (CCPP90); the Saturation Index, also calculated at a temperature of 90 degrees C (SI90); the Nucleation Index (NI) and the Measured Calcium Carbonate Precipitation (MCCP). These parameters are currently successfully used in The Netherlands. The development of new parameters to predict scaling in domestic heating equipment has resulted in a better understanding of processes involved. Even now unexpected and at first sight contradictory results are obtained frequently. With the use of the developed measuring techniques, solutions may be found to combat excessive scaling.