High Water Hardness Research Articles

Association of consumption of excess hard water, body mass index and waist circumference with risk of hypertension in individuals living in hard and soft water areas.

Chronic exposure to soft drinking water increases the risk of hypertension. We conducted a cross-sectional study in 2017 in two study areas in the Poldasht County to assess the relation of hardness, body mass index and waist circumference with risk of hypertension. Total water hardness was measured by gravimetric methods. Hardness of > 180ppm was considered to be hard drinking water. The Shiblu and Gharghologh areas had a four times higher mean total hardness level in drinking water (968.69mg/L as CaCO3) than the Sarisoo and Agh Otlogh (180mg/L as CaCO3) areas. According to the results of the study, the prehypertension prevalence in areas with high and low water hardness was calculated as 23.15% (18.11-29.15) and 46.84% (37.61-57.64), respectively. Moreover, the result showed the prevalence of hypertension and prehypertension was higher in regions with low hardness than those with high hardness, which was statistically significant (P < 0.001). The results of logistic regression showed that age, body mass index, waist circumference and hardness of drinking water were significantly related to hypertension. Accordingly, hypertension was low in people of regions with high hardness (OR 0.26, 0.17-0.42). This report examined whether total hardness in drinking water was protective against hypertension. This is an important finding for the ministry of human health as well as for the water and sewage company.

Study on Operational Conditions to Minimize Membrane Fouling in Membrane Bioreactor (MBR) System for Wastewater Treatment-Preliminary Pilot Tests

In this study, effect of antiscalant usage on minimizing of membrane fouling due to high water hardness during wastewater treatment tests run by a pilot-scale membrane bioreactor (MBR) system. The membranes used in these studies were Kubota flat sheet MBR membranes made from polyethylene with a pore size of 0.4 micrometer. Preliminary tests were carried out with tap water for sixty days of operation. To investigate the applicability and the effect of antiscalant usage, four experiments (two experiments with tap water and two experiments with wastewater) were carried out and each experiment lasted for 29 days. The tests were carried out in the presence and in the absence of antiscalant. Fouling on MBR membranes was investigated by monitoring flux decline versus time. In tap water tests, unstable flux was observed initially then a flux decline due inorganic scaling. On the other hand, the flux was almost constant up to end of the experiment in the presence of antiscalant. During wastewater tests (in the absence of antiscalant), the flux decline was observed within ten days of operation while during wastewater tests in presence of antiscalant, the flux did not decline until twenty days of operation. The use of antiscalant did not influencethe efuent quality. According to the quality analyses results for MBR efuent, removal efciencies for COD, PO4-P, and total N were 95%, 98% and 40%, respectively. In addition,99% of total suspended solid rejection and 98% of color rejection were obtained in the presence or absence of antiscalant.

Effects of environmental skin stressors on filaggrin degradation products: importance for eczema.

Atopic dermatitis (AD) is a common and complex inflammatory skin disease. It has a genetic component but is also strongly influenced by the environment. Clinicians caring for patients with AD are aware of the effects of climate on the onset of flares, for example. Epidemiological studies have linked high domestic water hardness and chlorine content with AD prevalence in children.

Validation of the nickel biotic ligand model for locally relevant species in Australian freshwaters.

Australian freshwaters have relatively low water hardness and different calcium (Ca) to magnesium (Mg) ratios compared with those in Europe. The hardness values of a substantial proportion of Australian freshwaters fall below the application boundary of the existing European nickel biotic ligand models (Ni BLMs) of 2 mg Ca/L. Toxicity testing was undertaken using Hydra viridissima to assess the predictive ability of the existing Ni BLM for this species in extremely soft waters. This testing revealed an increased competitive effect of Ca and Mg with Ni for binding to the biotic ligand in soft water (<10 mg CaCO3 /L) than at higher water hardness. Modifications were made to the Ni BLM by increasing the binding constants for Ca and Mg at the biotic ligand to account for softer waters encountered in Australia and the more important competitive effect of Ca and Mg on Ni toxicity. To validate the modified Ni BLM, ecotoxicity testing was performed on 5 Australian test species in 5 different natural Australian waters. Overall, no single water chemistry parameter was able to indicate the trends in toxicity to all of the test species. The modified Ni BLMs were able to predict the toxicity of Ni to the test species in the validation studies in natural waters better than the existing Ni BLMs. The present study suggests that the overarching mechanisms defining Ni bioavailability to freshwater species are globally similar and that Ni BLMs can be used in all freshwater systems with minor modifications. Environ Toxicol Chem 2018;37:2566-2574. © 2018 SETAC.

Attoriolong Tradition of Lake Preservation

Lake as a source of life for the fishermen has a very significant potential in influencing the views and behaviour of the fishing community’s culture. Events such as tidal lake erratic, flooding, high hardness water waves, even the lack of fish catches and the death of sailors in the lake, are symptoms that serve as the base outlook for the fishermen errors that they do against the unseen force which they consider to be the ruler of the lake. The fishing community of Lake Tempe has run attoriolong and established rules related to the management of the lake since the pre-Islamic period (before 1610 AD), led by a Macua Tappareng. Macua Tappareng is considered understand the ancestor details and rules in controlling the use of the lake, including the mystical of the lake. This study explores the local wisdom of coastal fishing communities of Lake Tempe in interacting with the lake led by Macua Tappareng. Macua Tappareng hereditary ensures that attoriolong tradition with all the rules and policies related to the lake is applied correctly. This research is a descriptive-analytic study that intends to describe as well as analyze the regulations and procedures on how Macua Tappareng in preserving the lake. The research shows that Macua Tappareng has the legitimacy and strategic position in protecting the lake, as evidenced by the continued preservation of some rules of fishing, such as a ban on fishing in particular place and time. Besides, the tradition of Maccera’ Tappareng is still considered liabilities fishing communities in honour of the ruler of the lake even become additional tools of the governments in disseminating and implementing local regulations.

Wear Properties of Wood-plastic Composites Pretreated with a Stearic Acid-palmitic Acid Mixture before Exposure to Degradative Water Conditions

Wood–plastic composites (WPCs) are experiencing rapid growth in terms of applications where they may be subject to degradation and wear. This paper investigated the effect of sorghum straw (SS) fiber, pretreated with a mixture of stearic and palmitic acids, on the wear behaviors of polyvinyl chloride (PVC) composites in alternated simulated sea water and acid rain aqueous conditions. The results showed that the water resistance of the SS/PVC composites improved noticeably after pretreatment with 0.80 wt% stearic and 0.50 wt% palmitic acid (0.8SA-0.5PA). The SS/PVC composites pretreated with 0.8SA-0.5PA exhibited high water (moisture) resistance, hardness, mechanical, thermal, and wear resistance properties. Exposure to degradative water worsened interfacial bonding, and degraded the matrix strength and heat resistance, which reduced the wear resistance of the SS/PVC composites. The wear mechanism of the SS/PVC composites after 12 d of soaking was abrasive wear.

Two-stage selective recovery process of scandium from the group of rare earth elements in aqueous systems using activated carbon and silica composites: Dual applications by tailoring the ligand grafting approach

A steady, reliable and enhanced scale of scandium (Sc) supply is of paramount importance in the current industrial sector, specifically, in the production of solid oxide fuel cells and scandium based aluminum alloys. Despite an expensive price quote, the remarkable physical properties of Sc drive the need to foster alternate supply pools, including industrial wastes and stockpiles, to tackle the ever-increasing need in global markets. However, they are most often obtained as a combined by-product with other metals, Sc-Y silicate minerals or rare earth elements (REE). To achieve this, activated carbon (AC) was utilized together with nano silica to synthesize two groups of adsorbents varying in terms of the ligand grafting technique. The study revealed that the Method II composites were highly effective in REE recovery, even under the process conditions of high salinity and water hardness, and in the presence of oil and organic compounds. As a conclusive step, the REE adsorption process was also successfully validated with real acidic mine drainage (AMD). Additionally, the synthesized adsorbents were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), X-ray diffraction spectroscopy (XRD), organic elemental and zeta potential (ZP) analysis to gain a better insight into the underlying mechanism characterizing the adsorption process.

The preparation, microstructure and mechanical properties of a dense MgO-Al2O3-SiO2 based glass-ceramic coating on porous BN/Si2N2O ceramics.

A dense MgO–Al2O3–SiO2 based glass-ceramic coating was prepared by a doctor blade process on a porous BN/Si2N2O ceramic surface followed by heat treatment at 1050 °C under nitrogen flow. The phase composition, microstructure, mechanical properties and water absorption of the coating were studied. The coating consisted of α-cordierite phase with a small amount of glass phase. The dense coating without pores and cracks was favorable to seal and densify the porous ceramic surface due to part of the molten glass infiltrating the surface pores. The coating was defect-free and tightly bonded to the substrate because of a larger bonding area between the coating and the substrate. The elastic modulus and bending strength of the glass-ceramic coating were 37.9 GPa and 67.1 MPa, respectively. Moreover, the coated samples had a high Vickers hardness and low water absorption.

Impact of water hardness on energy consumption of geyser heating elements

South Africa is an electricity-stressed country with a growing energy demand. Globally, hot water appliances are major consumers of electricity. Poor water quality for domestic purposes is a concern that may affect the efficiency of hot water appliances. Therefore, the Eskom Research, Testing, and Development Business Unit embarked on a study to examine total water hardness as a chemical parameter that may impact the power consumption of electrical geyser heating elements. An accelerated scaling method was developed to lime-scale the geyser heating elements for about 2 to 3 months. In addition, the geyser heating elements were tested with and without electronic descaler technology. The results showed that the accelerated scaling method developed for shortening the scaling time of geyser heating elements was successful. Furthermore, the results proved that scale formation of 1.5 kW and 3 kW geyser heating elements due to high total water hardness increased the power consumption by approximately 4% to 12%. This paper also presents energy-efficient electronic descaler technology as an alternative treatment of scaling for geyser heating elements. Keywords : electronic descaler technology, energy consumption, geyser heating element, scaling, total water hardness

Environmental impacts of crude oil spillages on water in Ibeno local government area of Akwa Ibom state, Nigeria

Crude oil spillage has been identified to be a regular occurrence in Upenekang village in Ibeno Local Government Area of Akwa Ibom State, Nigeria. This study has been carried out to find out the effect of crude oil spill on stream water and the environmental impact it has on the area. Using water samples obtained at varying distances from the spill site, the effects of the crude oil spill on the surface and underground stream water at the spill site were investigated by testing for the presence as well as the concentrations of toxic heavy metal pollutants. Analyses were also carried out for water conductivity, pH, temperature, hardness, total solids, total dissolved solids, turbidity, suspended solids, dissolved oxygen, carbon dioxide, COD, BOD, THC, sodium, magnesium, calcium, sulphate, nitrate, iron, copper, lead, chromium and cadmium concentrations using standard methods. The pH of all the samples of both the surface and underground stream water obtained at the spill site were observed to be acidic with very low dissolved oxygen, low COD, low BOD, high hydrocarbon content, high total dissolved solids, high water hardness and high toxic heavy metal concentrations (iron, copper, lead, chromium and cadmium) investigated for, all above admissible concentrations by World Health Organization’s standards. A one-way ANOVA showed that there is no significant influence of distance away from spill on the level of heavy metals in the water samples collected in the study area.Keywords: Crude oil spill, Upenekang, Water, WHO, ANOVA.

Acute toxicity of chlorpyrifos and carbosulfan to glochidia of the freshwater mussel Hyriopsis bialata Simpson, 1900.

The acute toxicity of carbosulfan and chlorpyrifos in formulated pesticides to glochidia (larvae) of the freshwater mussel (Hyriopsis bialata Simpson, 1900) was evaluated under static conditions in moderately hard dechlorinated tap water. Measured pesticide concentrations were 26 to 34% lower than nominal concentrations; therefore, all results are expressed in terms of measured active ingredient. Carbosulfan was relatively non-toxic to the mussel larvae with median effective concentrations (EC50) of carbosulfan at 24 and 48h greater than 0.10mg/L. The EC50s of chlorpyrifos at 24 and 48h were 0.083 and 0.078mg/L, respectively (measured concentrations). The 48-h EC50 of a combined exposure to a mixture of chlorpyrifos and carbosulfan at a constant ratio of 2.9:1 was 0.0142:0.049mg CP:CB/L. In a separate experiment, the effect of water hardness on carbosulfan, chlorpyrifos, or a combined exposure was assessed using glochidia exposed to either soft, moderately hard, or hard reconstituted water. There was no effect of water hardness on the survival of glochidia after 24- or 48-h exposure to carbosulfan. The chlorpyrifos 48-h EC50s in soft water, moderately hard water, and hard water were 0.18, 0.11, and 0.16mg/L, respectively. The data indicate that the lowest water hardness resulted in the highest survival of glochidia, whereas an increase to moderate water hardness resulted in significantly decreased survival of glochidia (F=15.5, P<0.05). The EC50s of a combined exposure at 48h in soft water, moderately hard water, and hard water were 0.124:0.044, 0.132:0.047, and 0.064:0.022mg CP:CB/L, respectively. The data indicate that the combined toxicity was lowest at low and moderate water hardness, whereas an increase to high water hardness resulted in a significantly decreased survival of glochidia. After 48h, the toxicity of the combined chlorpyrifos and carbosulfan exposure in soft and hard water was greater than that of chlorpyrifos alone.

Removal of phosphorus from phosphonate-loaded industrial wastewaters via precipitation/flocculation

Phosphonates are to be removed from industrial wastewater before they reach municipal wastewater treatment plants or surface waters. Industrial wastewaters contaminated with the phosphonates 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), 1-hydroxyethylidene-(1,1-diphosphonic acid) (HEDP), nitrilotrimethylphosphonic acid (NTMP), ethylenediamine tetra(methylene phosphonic acid) (EDTMP) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP) can be subdivided into: (1) mostly clear concentrates with a high water hardness, and (2) organically polluted wastewaters, for instance from the paper and textile industries. Our own flocculation experiments with FeIII and AlIII salts showed that, at a pH of 7.5, the adsorption affinity of polyphosphonates onto iron hydroxides and aluminum hydroxides significantly decreases with an increasing number of C-P bonds (HEDP>NTMP>EDTMP>DTPMP). In comparison to pure water spiked with phosphonates, the total P removal from concentrates occurred at similar and even lower flocculant dosage concentrations (ß=4–8) (ß is the molar ratio of dosed metal concentration to total P concentration in the raw sample). In organically polluted industrial wastewaters, the formation of flocks, and therefore the total P decrease, only occurred after exceeding a certain flocculant concentration, which varied strongly depending on the wastewater type (ß=0.6–86). Below that concentration, the flocculant underwent complexation, and no elimination could be observed. For most of the wastewaters, the required ß values for at least 80% total P decrease were very similar for both FeIII and AlIII. Furthermore, Ca(OH)2 as flocculant turned out to be an effective tool for total P removal and simultaneous softening of calcareous concentrates.

Aquatic invertebrate community structure of selected endorheic wetlands (pans) in South Africa

Shallow wetlands, such as pans, are not well studied in South Africa, even though they perform many important functions, such as providing an important food source for migratory birds and habitat to highly specialized fauna. Aquatic invertebrate diversity, abundance, and water quality in pans were analysed seasonally from 3 provinces in South Africa with contrasting climates. Univariate and multivariate statistics were used to assess similarities in aquatic invertebrate communities and water chemistry among pans. Pans inundated for extended periods had greater aquatic invertebrate diversity, and several of these taxa were not adapted to the temporary environment common to pans. The subtropical region had greater aquatic macroinvertebrate diversity than semiarid regions due to more rainfall per annum in the subtropical region. Water temperature was a major driving factor for diversity, with greater diversity occurring in warmer seasons. High water hardness and salinity were found to drive decreased diversity and encourage the presence of hardy and more tolerant species. Understanding the importance of these aforementioned factors (i.e., pan longevity, temperature, water hardness, and salinity) influencing aquatic invertebrate biodiversity in pans provides a baseline for future studies and impact assessments on these important and understudied systems.

Corrosion potential of alluvial groundwaters in Velika Morava River basin

This paper discusses the corrosion and scaling potential of shallow groundwater from two aquifers(Kljuc and Trnovce) in the Velika Morava River alluvium. Values of the most commonly used indicators, such as Langelier Saturation Index (LSI), Ryznar Stability Index, Larson-Skold Index and Aggressive Index were calculated to determine corrosion potential and stability. Additionally, the paper analyzes the psysico-chemichal parameters that impact corrosion processes. The calculated results show that Trnovce water source has more aggressive groundwater then - the Kljuc water source. Based on the calculated RSI values, 92.8% of the samples from Trnovce and 84.2% of the samples from Kljuc groundwater sources show corrosive potential. Calculated LSI shows that 82% of the groundwater samples from Trnovce and 36.8% of the samples from Kljuc have negative values, which implies corrosive properties and inability to retain existing CaCO3. The Aggressive Index indicates that 67.8% of the samples from Trnovce belong to moderately corrosive waters, unlike groundwaters from Kljuc water source, where only 26.3% of the samples show these properties. The small calculated values of LSkI Index, which are significantly below the limit of 0.8, imply that protective layer (film) cannot be formed. High water hardness are characteristic for both water sources, also as periodically elevated concentrations of dissolved oxygen, could contribute to the development of corrosion processes.

Effects of Water Hardness on Dyeing of Cotton Fabrics with Different Types of Reactive Dyes and Shade Percentages

This research was investigated the influence of water hardness on dyeing of cotton fabric with three types of reactive dyes (Synozol, Ramazol and Setazol). The effects of various fastness (color fastness to wash, abrasion test, Rubbing test and Perspiration test) properties of dyes were also studied and reported in this paper in details. Single color (Blue) is used for the shade of 1% and 2% and varied water hardness of 120 ppm, 70 ppm and 9 ppm respectively. The main objective of this paper was to find out the parameters of various fastness properties at different range of water hardness in the application of different types of reactive dyes. It is visualized that different amount of water hardness showed in different fastness for using three types of reactive dyes having shade of 1% and 2%. We reported that water hardness up to 9 ppm, for using three types of reactive dyes showed excellent wash fastness and it deteriorates with increasing hardness. Setazol 1% & 2%, showed highest abrasion resistance at 9 ppm water hardness compare to other dyes at higher water hardness. Rubbing test result also showed very good for 9 ppm water hardness in three reactive dyes irrespective of shade percentage. The perspiration test result is good at 9 ppm water hardness for all types of reactive dyes with all shade percentages.

Removal of Dissolved Organic Carbon (DOC) from High DOC and Hardness Water by Chemical Coagulation: Relative Importance of Monomeric, Polymeric, and Colloidal Aluminum Species

This study investigates the mechanism of Dissolved Organic Carbon (DOC) removal from water with high alkalinity and DOC, typical in the Canadian Prairie, by three aluminum based coagulants: aluminum sulphate (alum), polyaluminum chloride (PACl), and aluminum chlorohydrate (ACH). Our focus is to discern the role of aluminum species: Ala, Alb, and Alc to explain the performance of these coagulants in the removal of DOC. Removal of organic compounds is quantified by measurement of DOC, DOC fractions, and UV254.Results show that coagulation with alum at pH of 6.0 achieves highest DOC removal attributed to the highest content of in situ formed polymeric species (Alb). At pH adjusted to 7 and 8 ACH shows the highest content of Alb and consequently better removal of DOC compared to alum and PACl. When no pH adjustment is applied, coagulation with ACH achieves the highest DOC and UV removal, because of the highest concentration of Alb and Alc species in the solution.Trihalomethane Formation Potential (THMFP) of the water after the application of coagulation has also been studied. Water coagulated with alum shows the lowest trihalomethane formation potential (94.7 μg L−1 T) in comparison to the raw water (202.4 μg L−1) followed by ACH and PACl. This can be related to the coagulant effectiveness in reduction of hydrophobic acid (HPOA) as the main precursor for THMs formation.

Study on the desalination of high hardness water by electrodeionization reversal

In this study, the simultaneous removal of cationic ions (Ca2+, Mg2+, Na+, and K+) from synthetic aqueous solutions using electrodeionization reversal (EDIR) was investigated. Under the condition of relatively high-concentration influent, characteristic curves of V–I and R–I were plotted at first and the polarity reversal period of 60 min or shorter was determined based on the resistance–time (R–T) relationship. Effects of various operation parameters including dilute flow rates (15, 30, 60, and 90 mL min−1) and cation–anion resin volume ratios (3:7, 4.7:5.3, and 7:3) were studied, respectively. The experimental results showed that the operating current of 0.85 A, dilute flow rate of 30 mL min−1, and cation–anion volume ratio of 4.7:5.3 were optimal for the process performance. The average removal efficiencies of cations were more than 88% (i.e. 93.12–94.56% for Ca2+, 96.21–97.14% for Mg2+, 89.11–90.76% for Na+, and 92.99–95.35% for K+) after three repeated experiments without membrane scaling. The transport of cations through ion exchange resins was evaluated in relation to hydrated ionic radius and ionic valence. Due to various affinities of cations to the resins, the migration of divalent ions was more enhanced compared to that of monovalent ions. This study would be helpful for applying EDIR process in the treatment of high-concentration water desalination.

Effects of ozone as a stand-alone and coagulation-aid treatment on the reduction of trihalomethanes precursors from high DOC and hardness water

This study investigates the effect of ozone as a stand-alone and coagulation aid on the removal of dissolved organic carbon (DOC) from the water with a high level of DOC (13.8 mgL−1) and calcium hardness (270 mgL−1) CaCO3.Natural water collected from the Assiniboine River (Manitoba, Canada) was used in this study.Effectiveness of ozone treatment was evaluated by measurement of DOC, DOC fractions, UV254, and trihalomethane formation potential (THMFP). Additionally, zeta potential and dissolved calcium concentration were measured to discern the mechanism of ozone reactions.Results indicated that 0.8 mg O3/mg DOC ozone stand-alone can cause up to 86% UV254 reduction and up to 27% DOC reduction.DOC fractionation results showed that ozone can change the composition of DOC in the water samples, converting the hydrophobic fractions into hydrophilic ones and resulting in the reduction of THMFP. Also, ozone caused a decrease in particle stability and dissolved calcium concentration. These simultaneous ozonation effects caused improved water flocculation and enhanced removal of DOC. This resulted in reduction of the coagulant dosage when ozone doses higher than 0.2 mg O3/mg DOC were applied prior to coagulation with ferric sulfate. Also, pre-ozonation-coagulation process achieved preferential THMFP removal for all of the ozone doses tested (0–0.8 mg O3/mg DOC), leading to a lower specific THMFP in pre-ozonated-coagulated waters than in the corresponding ozonated waters.

Ověření účinnosti a působení vybraných dezinfekčních prostředků

This research work is aimed to monitoring of selected disinfectants´activity in operational conditions. Hereby there have been monitored two acidic disinfectants Despon K and Mikasan D, which have had-by their producer-stated different recommended concentration. These solutions were monitored in viewpoint of their activity at different temperature, time of circulation, pH and water hardness. In this work there were measured pH of solutions in unloaded medium to be compared with pH of solutions in loaded medium and this measuring was carried out regularly each week within a one month period. During this period there was also monitored total plate count (TPC), which was stated in the dairy, where samples were taken two-times monthly. It has been found, that the disinfectants Mikasan D and Mikal 94D are effective even by high water hardness.

Research on Preparation and Performance of Environment Friendly Polybasic Non-Phosphate Scale and Corrosion Inhibitor

A quaternary non-phosphorus compound agent was prepared from polyaspartic acid (PASP), aconitic acid-acrylic acid copolymer (AA-AA), sodium gluconate and Zn2+. The performances of scale inhibiting and dispersing, corrosion inhibiting and biodegradability of the agent were studied. The results showed that when the formula was 4mg/L PASP , 8mg/L AA-AA, 20mg/L sodium gluconate and 2mg/L Zn2+, the corrosion rate was 0.0180 mm/a and the corrosion inhibition rate could reach up to 98.01% and the total concentration was not much high. The dynamic simulation test indicated that the scale inhibition and dispersing performance of the compound agent was excellent. In the complex water system which Cl- and SO42- contents were high, the corrosion inhibition rate on carbon steel was still above 90%. The quaternary compound agent applied to high hardness and high corrosivity water quality. It was a kind of high efficient environment friendly corrosion inhibitor, which could replace the phosphorous water treatment agents on the market.