Removal of Fluoride and Hardness in Dietary Intake (water) in Chronic Kidney Disease of unknown Etiology (CKDu) Prevalent Areas by Domestic Reverse Osmosis Units

The origin of Chronic Kidney Disease of unknown etiology (CKDu) that is rapidly invadingthe dry zone of Sri Lanka has not yet been identified. However, occurrence of the disease isthought to be linked with excess levels of fluoride and hardness in drinking water. Hence, thestudy herein focuses to evaluate the suitability of domestic Reverse Osmosis (RO) units;which introduced in CKDu affected areas to remove excess fluoride and hardness.Accordingly, the drinking water quality in CKDu prevalent areas in terms of fluoride andhardness was simulated in the laboratory and the removal of aforesaid constituents usingdomestic ROs was investigated.According to water quality analyses, domestic RO units effectively removed hardness even atextremely high initial concentrations, such as 1,730 mg/L (as CaCO3). Excessive removal ofCalcium and Magnesium by the RO units was observed, thus remineralization of thepermeate up to 80-100 mg/L as CaCO3 is required to ensure health benefits. Meanwhile,fluoride removal was observed to be highly dependent upon initial fluoride and hardnessconcentrations. It was not possible to suggest an „optimum removal level‟ for fluoride, wherepermeate fluoride concentration exceeded the maximum permissible WHO Drinking WaterGuideline value of 1.5 mg/L. However, it may arise at a point where fluoride and hardnessconcentrations in raw water fall within 1.7-3.5 mg/L and 570-1,130 mg/L as CaCO3,respectively.Plausible reasons for ineffective removal of fluoride could be the relatively small size andlow ionic charge of fluoride. Additionally, high concentration of heavy ions may interferewith fluoride adsorption of activated carbon filter in the domestic RO unit. Effective fluorideremoval could be achieved by adopting appropriate pre-treatment methods for hardnessremoval. Separate threshold levels for fluoride and hardness levels in drinking water shouldbe defined, especially for CKDu patients.Keywords: Chronic Kidney Disease, Domestic reverse osmosis units, Fluoride, Hardnes

Use of Reverse Osmosis Reject Water for Value Addition in Coco Substrate Industry

Previous studies corroborated that water enriched with various compounds is a major reasonfor Chronic Kidney Disease of Unknown Aetiology (CKDu) in Sri Lanka. Reverse osmosis(RO) units are being introduced in the CKDu prevalent areas for water purification.Generally, the RO reject water is disposed of directly to the ground and/or used for irrigationpurposes because it contains several minerals, which are favourable for the growth of plants.However, this practice may cause any negative environmental issues.Calcium nitrate is used as a value addition in coco substrate industry to wash out sodiumfrom the coir products because sodium competes with other cations which are essential forplant growth in the process of adsorption. However, discharging the spent calcium nitratesolution to land for irrigation purposes may lead to nitrate pollution. This study investigatesthe possibility of using RO reject water, which has considerably high amounts of calcium, asan alternative for the use of calcium nitrate, which may also lead to reduction of cost ofimporting calcium nitrate. Leachability tests were carried out using husk chips as the solidmedium with RO reject water and calcium nitrate as the treatment solution, respectively.When RO reject water was used as the washing solution, the results manifested (amount ofcalcium, magnesium adsorbed and sodium, potassium leached out) that the leachabilitypotential was well within the acceptable range as per the protocols. Based on the findings,RO reject water could be proposed as an alternative source to calcium nitrate.Keywords: Calcium nitrate, Coco substrate, Husk chips, Reverse osmosis, Water purificatio

Suitability of Clay Water Filter for the Removal of Nephrotoxic Constituents in CKDu Prevalent Areas

Consumption of water composed of different nephrotoxic constituents such as Hardness, Fluoride, Cadmium, and Aluminum has manifested to be triggering causal factors of Chronic Kidney Disease of unknown etiology (CKDu) and non-nephrotoxic health hazards. Hence, it is a prerequisite to remove these nephrotoxic constituents from water to levels less than the permissible drinking water guideline values. Thus, an introduction of clay water filters has been reckoned to be a solution, which will provide safe drinking water to people in CKDu prevalent areas. This filter media is composed of clay and shifted rice husk mixture. The suitability of the clay water filter unit to remove nephrotoxic constituents is, however, has not been comprehensively investigated. Therefore, the present study focuses on investigating the suitability of the clay water filter unit in the removal of nephrotoxic constituents effectively and efficiently from potable water. Feed water was, therefore, synthesized simulating wet (October & November) and extreme wet (December) seasons in the dry zone in Sri Lanka, in which the feed water constituted of Hardness of 350 and 150 mg/l, Fluoride of 3 and1 mg/l, Cadmium of 1 and 1 mg/l and Aluminum of 1 and 1 mg/l for both wet and extreme wet seasons respectively. With the assumption that four members of a family consume 8 l of water per day, samples were collected and analyzed. Average concentration values of the treated water were determined as Hardness of 340 and 148 mg/l, Fluoride of 0.92 and 0.87 mg/l, Cadmium of 0.69 and 0.58 mg/l, and Aluminum of 0.74 and 0.67 mg/l during wet and extreme wet seasons. Hardness values did not comply with drinking water guideline values of 250 mg/l (SLS- 613:2013) during the wet season and Cadmium of 0.003 mg/l (WHO Guideline) during both seasons. Aluminum and Fluoride values complied with WHO permissible drinking water guideline values of 0.9 mg/l and 0.6-1.5 mg/l respectively. The XRD, FTIR, ESEM-EDX analyses of filter media of the clay filter unit confirmed that the filter media composed of clay and non-clay minerals mainly, silicon oxide, quartz, albite, gottardiite and salicylic acid, with prominent elements of aluminum, calcium, magnesium, oxygen, silicon, and sodium. In such minerals, functional groups such as Si-O-Si, Si-O, -OH, -COOH and Si-OH were found to be the most dominant ligands that can form complexes with ions in water. Al3+ions showed strong interactions with such functional groups more than Ca2+, Mg2+ and Cd2+ions did, resulting in a better removal of Aluminum through the formation of covalent bonds between Aluminum and ligands. Complexation of F- with Al3+, Ca2+, and Mg2+ions in clay minerals was too seen indicating an excessive removal of Fluoride in the water. However, Ca2+, Mg2+,and Cd2+showed poor interactions with ligands resulting in an ineffective and an inefficient removal of Ca2+, Mg2+and Cd2+ ions in water. Hence, it could be inferred that the use of the clay filter unit is not a promising solution to remove high concentrations of Ca2+, Mg2+and Cd2+ions from water in CKDu prevalent areas.Keywords: Aluminum, Cadmium, Drinking water, Fluoride, Hardnes

Suitability of Clay Water Filter for the Removal of Nephrotoxic Constituents in CKDu Prevalent Areas

Consumption of water composed of different nephrotoxic constituents such as Hardness, Fluoride, Cadmium, and Aluminum has manifested to be triggering causal factors of Chronic Kidney Disease of unknown etiology (CKDu) and non-nephrotoxic health hazards. Hence, it is a prerequisite to remove these nephrotoxic constituents from water to levels less than the permissible drinking water guideline values. Thus, an introduction of clay water filters has been reckoned to be a solution, which will provide safe drinking water to people in CKDu prevalent areas. This filter media is composed of clay and shifted rice husk mixture. The suitability of the clay water filter unit to remove nephrotoxic constituents is, however, has not been comprehensively investigated. Therefore, the present study focuses on investigating the suitability of the clay water filter unit in the removal of nephrotoxic constituents effectively and efficiently from potable water. Feed water was, therefore, synthesized simulating wet (October & November) and extreme wet (December) seasons in the dry zone in Sri Lanka, in which the feed water constituted of Hardness of 350 and 150 mg/l, Fluoride of 3 and1 mg/l, Cadmium of 1 and 1 mg/l and Aluminum of 1 and 1 mg/l for both wet and extreme wet seasons respectively. With the assumption that four members of a family consume 8 l of water per day, samples were collected and analyzed. Average concentration values of the treated water were determined as Hardness of 340 and 148 mg/l, Fluoride of 0.92 and 0.87 mg/l, Cadmium of 0.69 and 0.58 mg/l, and Aluminum of 0.74 and 0.67 mg/l during wet and extreme wet seasons. Hardness values did not comply with drinking water guideline values of 250 mg/l (SLS- 613:2013) during the wet season and Cadmium of 0.003 mg/l (WHO Guideline) during both seasons. Aluminum and Fluoride values complied with WHO permissible drinking water guideline values of 0.9 mg/l and 0.6-1.5 mg/l respectively. The XRD, FTIR, ESEM-EDX analyses of filter media of the clay filter unit confirmed that the filter media composed of clay and non-clay minerals mainly, silicon oxide, quartz, albite, gottardiite and salicylic acid, with prominent elements of aluminum, calcium, magnesium, oxygen, silicon, and sodium. In such minerals, functional groups such as Si-O-Si, Si-O, -OH, -COOH and Si-OH were found to be the most dominant ligands that can form complexes with ions in water. Al3+ions showed strong interactions with such functional groups more than Ca2+, Mg2+ and Cd2+ions did, resulting in a better removal of Aluminum through the formation of covalent bonds between Aluminum and ligands. Complexation of F- with Al3+, Ca2+, and Mg2+ions in clay minerals was too seen indicating an excessive removal of Fluoride in the water. However, Ca2+, Mg2+,and Cd2+showed poor interactions with ligands resulting in an ineffective and an inefficient removal of Ca2+, Mg2+and Cd2+ ions in water. Hence, it could be inferred that the use of the clay filter unit is not a promising solution to remove high concentrations of Ca2+, Mg2+and Cd2+ions from water in CKDu prevalent areas.Keywords: Aluminum, Cadmium, Drinking water, Fluoride, Hardnes

Use of Reverse Osmosis Reject Water for Value Addition in Coco Substrate Industry

Previous studies corroborated that water enriched with various compounds is a major reasonfor Chronic Kidney Disease of Unknown Aetiology (CKDu) in Sri Lanka. Reverse osmosis(RO) units are being introduced in the CKDu prevalent areas for water purification.Generally, the RO reject water is disposed of directly to the ground and/or used for irrigationpurposes because it contains several minerals, which are favourable for the growth of plants.However, this practice may cause any negative environmental issues.Calcium nitrate is used as a value addition in coco substrate industry to wash out sodiumfrom the coir products because sodium competes with other cations which are essential forplant growth in the process of adsorption. However, discharging the spent calcium nitratesolution to land for irrigation purposes may lead to nitrate pollution. This study investigatesthe possibility of using RO reject water, which has considerably high amounts of calcium, asan alternative for the use of calcium nitrate, which may also lead to reduction of cost ofimporting calcium nitrate. Leachability tests were carried out using husk chips as the solidmedium with RO reject water and calcium nitrate as the treatment solution, respectively.When RO reject water was used as the washing solution, the results manifested (amount ofcalcium, magnesium adsorbed and sodium, potassium leached out) that the leachabilitypotential was well within the acceptable range as per the protocols. Based on the findings,RO reject water could be proposed as an alternative source to calcium nitrate.Keywords: Calcium nitrate, Coco substrate, Husk chips, Reverse osmosis, Water purificatio

Removal of Fluoride and Hardness in Dietary Intake (water) in Chronic Kidney Disease of unknown Etiology (CKDu) Prevalent Areas by Domestic Reverse Osmosis Units

The origin of Chronic Kidney Disease of unknown etiology (CKDu) that is rapidly invadingthe dry zone of Sri Lanka has not yet been identified. However, occurrence of the disease isthought to be linked with excess levels of fluoride and hardness in drinking water. Hence, thestudy herein focuses to evaluate the suitability of domestic Reverse Osmosis (RO) units;which introduced in CKDu affected areas to remove excess fluoride and hardness.Accordingly, the drinking water quality in CKDu prevalent areas in terms of fluoride andhardness was simulated in the laboratory and the removal of aforesaid constituents usingdomestic ROs was investigated.According to water quality analyses, domestic RO units effectively removed hardness even atextremely high initial concentrations, such as 1,730 mg/L (as CaCO3). Excessive removal ofCalcium and Magnesium by the RO units was observed, thus remineralization of thepermeate up to 80-100 mg/L as CaCO3 is required to ensure health benefits. Meanwhile,fluoride removal was observed to be highly dependent upon initial fluoride and hardnessconcentrations. It was not possible to suggest an „optimum removal level‟ for fluoride, wherepermeate fluoride concentration exceeded the maximum permissible WHO Drinking WaterGuideline value of 1.5 mg/L. However, it may arise at a point where fluoride and hardnessconcentrations in raw water fall within 1.7-3.5 mg/L and 570-1,130 mg/L as CaCO3,respectively.Plausible reasons for ineffective removal of fluoride could be the relatively small size andlow ionic charge of fluoride. Additionally, high concentration of heavy ions may interferewith fluoride adsorption of activated carbon filter in the domestic RO unit. Effective fluorideremoval could be achieved by adopting appropriate pre-treatment methods for hardnessremoval. Separate threshold levels for fluoride and hardness levels in drinking water shouldbe defined, especially for CKDu patients.Keywords: Chronic Kidney Disease, Domestic reverse osmosis units, Fluoride, Hardnes