Draft Specification for Domestic (household) Defluoridation Filter Unit (DDFU/DDU) by Unicef

Fluoride is a normal constituent of most natural waters and its concentration varies depending on the water source. Surface waters seldom have fluoride concentrations beyond 0.3 mg/lit. Geological processes, weathering of fluoride bearing minerals and hydrogeological conditions can lead to higher fluoride levels in groundwater in certain areas, which can become endemic for fluorosis.

Link : http://www.watersanitationhygiene.org/References/EH_KEY_REFERENCES/WATER/Water%20Quality/Fluoride/Specifications%20for%20Domestic%20Defluoridation%20%28UNICEF%29.pdf

High Efficiency Fluoride Treatment “F-crest” By Takumi Fujita

 A high efficiency neutral fluoride treatment based on calcium phosphate salts as a main raw material
for solidification and insolubilization of fluorine-containing waste as fluoro-apatite in a short period
of time and high efficiency.  Solidification and insolubilization of a low concentration of fluoro-compounds in the environment as sparingly soluble calcium phosphate salts (fluoro-apatite) as suggested by the biomimetic nano surface reaction of applying a fluoro-chemical to teeth for protection of decay.  Very reactive with fluoro-compounds, which are effectively insolubilized with a small amount of “F-crest”. Completion of solidification and insolubilization of fluorine-contaminated soil in a short period of time. No need to replace the contaminated soil. No decrease of soil quality for a long period of time after treatment. More efficient in treating fluorine-containing wastewater than the conventional process based on aluminum sulfate (reduced to about 1/10th of additives). Little generation of sludge.

 link :http://www.chubu.meti.go.jp/kankyo/data/chiyoda_english.pdf

Fluoride Removal from Ground Water by Gama-Alumina Coated Ceramic Honeycomb By K. Dasha , U. S. Hareeshb , R. Johnsonb and J. Arunachalama

Studies have been carried out on defluoridation of ground water using gamma alumina coatings on a ceramic honeycomb. The sol gel coated gamma alumina adsorbent was found to adsorb fluoride rapidly and effectively. Coatings on ceramic honeycomb were prepared using a sol of dispersible precursor of boehmite (-AlOOH). The boehmite coating, on calcination at 500°C transformed to alumina. The fluoride removal performance was investigated as a function of the fluoride concentration and flow rate. It was observed that fluoride removal is low at higher flow rate. The specific fluoride uptake capacity was 15400mg of Fremoved /kg of coated -alumina on the ceramic honeycomb from fluoride solution, whereas in case of ground water, the capacity was 12600 mg of Fper kg of coated alumina. The regeneration was effected by passing a dilute solution of aluminum sulfate solution. A fluoride removal kit consisting of five ceramic honeycombs in series was evaluated to defluoridate ground water. Around 200 liters of ground water (initial Fconc. of 5 ppm) could be defluoridated to permissible level of Fconcentration. It is much easier and convenient to regenerate the alumina coated on the honeycombs due to open channel structures of the honeycomb.

Domestic Defluoridation of Water Using Locally Produced Activated Alumina by N V Dzung , H H Phong, N N Long, N T Quang and P Waldemar

A low-cost defluoridator for domestic use is developed, based onactivated alumina as a sorption medium. The filter column is 11.4 cm in diameter and 1 m in height. It is designed to contain about 8 L or about 3 kg of alumina. The alumina is prepared by using aluminium sulphate and sodium hydroxide to precipitate aluminium hydroxide at 60-70 oC. The precipitate is settled, washed,granulated and calcined at 550 - 600 oC for 4 hours. A column test in the laboratory revealed that the fresh alumina could remove fluoride from 5 mg/L to < 0.7 mg/L at a capacity of 1.2 g/kg. The developed filter allows for monthly regeneration of the medium by the users themselves. A quantity of 0.4 kg of aluminium sulphate is used in the regeneration. The filter operates upwards, while the regeneration operates downwards in the filter column. Field-testing data show that the filters could treat water containing about 2 mgF/L down to 0.15 - 0.46 mg/L, thus an average removal efficiency of 85 %. Monitoring of a filter through 5 operation periods shows that the regenerated alumina loaded with water containing 2.6 mgF/L could treat the water at an efficiency of 89 %. Themedium capacity is estimated to be 0.7 gF/kg regenerated alumina. Field experiences show that the villagers very well accept the filter; it is easy to operate and to maintain and the filter costs are affordable to the families, about 45 USD for purchase and 20 US Cents for the monthly regeneration.

Status of Water Treatment Plants in India

Water is a precious commodity. Most of the earth water is sea water. About 2.5% of the water is fresh water that does not contain significant levels of dissolved minerals or salt and two third of that is frozen in ice caps and glaciers. In total only 0.01% of the total water of the planet is accessible for consumption. Clean drinking water is a basic human need. Unfortunately, more than one in six people still lack reliable access to this precious resource in developing world. India accounts for 2.45% of land area and 4% of water resources of the world but represents 16% of the world population. With the present population growth-rate (1.9 per cent per year), the population is expected to cross the 1.5
billion mark by 2050. The Planning Commission, Government of India has estimated the water demand increase from 710 BCM (Billion Cubic Meters) in 2010 to almost 1180 BCM in 2050 with domestic and industrial water consumption expected to increase almost 2.5 times. The trend of urbanization in India is exerting stress on civic authorities to provide basic requirement such as safe drinking water, sanitation and infrastructure. The rapid growth of population has exerted the portable water demand, which requires exploration of raw water sources, developing treatment and distribution systems.

Link : http://cpcb.nic.in/upload/NewItems/NewItem_103_statusofwaterqualitypackage.pdf

Fluoride in Drinking Water: Health Effects and Remediation by Meththika Vithanage and Prosun Bhattacharya

Fluoride at low concentration is an essential element for dental health. However groundwater in many countries has exceeding concentrations of fluoride, which poses a health threat to millions of people around the world. It has been estimated that more than 200 million people from among 25 nations are suffering from fluorosis due to the consumption of fluoride-rich drinking water. Fluoride contamination is mostly geogenic however, in some cases anthropogenic industrial inputs may cause a threat. Many techniques have been developed for defluoridation. However a solution is still to be found especially for the household and community supply.

Link : https://www.researchgate.net/publication/272163388_Fluoride_in_Drinking_Water_Health_Effects_and_Remediation

A Low Cost Approach To Synthesize Sand Like Alooh Nanoarchitecture (SANA) And Its Application In Defluoridation Of Water By Gaurab Saha , Shihabudheen M. Maliyekkal, P.C. Sabumon, T. Pradeep

This paper describes a chitosan template assisted synthesis of nanocrystalline aluminium oxyhydroxide (g-AlOOH) at an ambient temperature (30  2 C) and atmospheric pressure. High ability of the composite in removing fluoride from water has been demonstrated. The structural, morphological and compositional characteristics of the composite were studied using various spectroscopic and microscopic techniques. The results showed that the composite has nanoarchitecture comprising a number of g-AlOOH nanoparticles of size less than 10 nm attached to the fibrils of chitosan. Batch and continuous flow adsorption experiments were conducted to assess the parameters that influence the adsorption process. The parameters investigated include contact time, initial fluoride concentration, adsorbent dose, pH of the solution, co-existing ions in water, and size of the adsorbent granules. The composite showed good affinity to fluoride and the maximum uptake capacity was 13.47 (mg/g) (mg/L)1/n as described by Freundlich isotherm model. The kinetics of adsorption was affected by the size of the granules and the kinetic data followed pseudo-second-order rate equation. Except bicarbonate and sulfate, other competing ions studied did not affect the uptake of fluoride significantly. The high affinity to fluoride, simple and eco-friendly synthesis approach demonstrate the utility of the material for defluoridation of water.

Link : https://www.researchgate.net/publication/269390883_A_low_cost_approach_to_synthesize_sand_like_AlOOH_nanoarchitecture_SANA_and_its_application_in_defluoridation_of_water

A review on adsorbents used for defluoridation of drinking water By Poonam Mondal, Suja George

Drinking water has been contaminated over decades with some very detrimental compounds such as fluoride. Exposure to fluoride through drinking water above the permissible limit (1.0–1.5 mg/L) causes severe dental and skeletal fluorosis. Adsorption technique which deals with adsorbents for fluoride removal from an aqueous solution is a highly efficient and selective process. This review paper provides insights on adsorbents used and developed by researchers for defluoridation of drinking water. It includes various categories of adsorbents used and parameters affecting the whole process. Adsorbents studied by researchers are enlisted with their adsorption capacity, optimum pH, temperature, equilibrium isotherm, kinetics, interfering ions, thermodynamic studies and regeneration procedure adapted. Efforts are needed to develop low cost reusable adsorbents with high adsorption capacity. Although, some adsorbents are reported to show remarkable capacity for fluoride removal; still there is an urgent need for development of more novel adsorbents holding both economic and technological benefits.

The Influence Of Stereochemistry Of The Active Compounds On Fluoride Adsorption Efficiency Of The Plant Biomass By Hezron T Mwakabona, Revocatus L Machunda, Karoli N Njau

Several studies have reported various defluoridation capabilities of plant biomasses. The resultant variations in fluoride removal capacities are associated with the presence of different types of active functional groups in the respective biomasses. This study reports of the fluoride removal efficiencies of sisal leaf biomass in comparison. Comparison with other plant biomasses were made and hence the fluoride removal efficiencies of maize leaf (ML), goose grass (GG), banana false stem (BFS), Aloe vera (AV), untreated sisal fibre (USF) and sisal pith (SP) with similar active functional groups but different stereochemistry and solubility of the active compounds are reported. A portion of 0.5 g of each biomass was mixed with a 10 mg/l fluoride solution in a 10 ml portions under the same experimental conditions. The maximum fluoride removal capacity of sisal fibre biomass was found to be 26.6 %. By comparison, the fluoride removal efficiencies of ML, GG, BFS, AV, USF and SP were found to be, 4.1, 4.6, 7.1, 26.6, 29.4 and 47.3 % respectively. This suggests that, stereochemistry and solubility of the active compounds have a significant role to play in water defluoridation by plant biomasses, and thus, knowledge of the stereochemistry and solubility of the active compounds in plant biomass is very important to fully unlock biomass defluoridation potentials.

Link : http://article.sciencepublishinggroup.com/pdf/10.11648.j.ajche.20140204.12.pdf

Preparation Of Cao Loaded Mesoporous Al2O3: Efficient Adsorbent For Fluoride Removal From Water By Desagani Dayananda , Narendra N. Ghosh , Venkateswara R. Sarva , Sivankutty V. Prasad , Jayaraman Arunachalam

In this paper, we report a simple chemical method for the preparation of CaO loaded mesoporous Al2O3 based adsorbents, which can be used for fluoride removal from water. The synthesized adsorbents were characterized by using powder X-ray diffractometer, N2 adsorption–desorption surface area and pore size analyzer and high resolution transmission electron microscope. CaO loaded mesoporous aluminas exhib-ited poor crystalline mesoporous structure having c-Al2O3 phase. The fluoride removal capacities of the synthesized adsorbents were evaluated using batch adsorption studies. Kinetic data revealed that, the fluoride sorption on 20 wt.% CaO loaded mesoporous Al2O3 was rapid, and 90% fluoride removal was achieved within 15 min. CaO loaded mesoporous Al2O3 showed higher fluoride adsorption capacity (137 mg/g) and faster kinetics than mesoporous Al2O3.

Improvement of User Friendliness of a Simple Domestic Defluoridation Unit Using Activated Alumina by R. Agrawal, K. Margandan, K.Singh, R. Acharya, S. Sharma, K Qanungo

The user friendliness of an Activated Alumina (AA) based fluoride filter using a ceramic cartridge, and locally available food grade containers has been improved by using two ceramic cartridges. The ceramic cartridge serve the dual purposes of filtering out any suspended particles and providing enough contact time for the AA to absorb the fluoride from water. The fluoride filter has a flow rate of 3 lit./hr a marked improvement from 1.7 lit./hr. achieved with one ceramic cartridge. These filters have been tested in laboratory using fluoride contaminated ground water from a nearby village. The filter yielded a safe volume of 1300 lit. water (<1.5 ppm fluoride in outlet water) with a Specific Safe Water Yield of 520 mg/kg of AA and Fluoride Uptake Capacity of 863.2 mg/kg AA. The cost of the defluoridated water for the first cycle is Rs. 0.87/lit. which includes the cost of the filter and the AA. The recurring cost of operating the filter, if the AA is to be discarded after single use, is quite low at Rs. 0.22/lit. With a water usage of 20 litres per day for a family of four, no maintenance is required in form of regeneration of the AA bed before two months five days with an inlet fluoride conc. of 2.41 ppm. and Simplicity of design and easy fabrication makes this fluoride filter suitable for replication.

Link : http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.403.8547&rep=rep1&type=pdf

Fluoride Removal From Water By Adsorption—A Review By Amit Bhatnagar, Eva Kumar, Mika Sillanpaa

Fluoride contamination in drinking water due to natural and anthropogenic activities has been recognizedas one ofthe major problems worldwide imposing a serious threatto human health. Among several treatment technologies applied for fluoride removal, adsorption process has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. In this review, an extensive list of various adsorbents from literature has been compiled and their adsorption capacities under various conditions (pH, initial fluoride concentration, temperature, contact time, adsorbent surface charge, etc.) for fluoride removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested so far for fluoride removal. It is evident from the literature survey that various adsorbents have shown good potential for the removal of fluoride. However, still there is a need to find out the practical utility of such developed adsorbents on a commercial scale, leading to the improvement of pollution control.

Magnesium incorporated bentonite clay for defluoridation of drinking water by Dilip Thakre , Sadhana Rayalua, Raju Kawade , Siddharth Meshramb, J. Subrt , Nitin Labhsetwar

Low cost bentonite clay was chemically modified using magnesium chloride in order to enhance its
fluoride removal capacity. The magnesium incorporated bentonite (MB) was characterized by using
XRD and SEM techniques. Batch adsorption experiments were conducted to study and optimize vari-
ous operational parameters such as adsorbent dose, contact time, pH, effect of co-ions and initial fluoride concentration. It was observed that the MB works effectively over wide range of pH and showed a maximum fluoride removal capacity of 2.26 mg g−1 at an initial fluoride concentration of 5 mg L−1, which is much better than the unmodified bentonite. The experimental data fitted well into Langmuir adsorption isotherm and follows pseudo-first-order kinetics. Thermodynamic study suggests that fluoride adsorption on MB is reasonably spontaneous and an endothermic process. MB showed significantly high fluoride removal in synthetic water as compared to field water. Desorption study of MB suggest that almost all the loaded fluoride was desorbed (∼97%) using 1 M NaOH solution however maximum fluoride removal decreases from 95.47 to 73 (%) after regeneration. From the experimental results, it may be inferred that chemical modification enhances the fluoride removal efficiency of bentonite and it works as an effective adsorbent for defluoridation of water.

Link : https://www.researchgate.net/publication/44592308_Magnesium_Incorporated_Bentonite_Clay_for_Defluoridation_of_Drinking_Water

Defluoridation of drinking water using chemically modified bentonite clay by Sanjay P. Kamble , Priyadarshini Dixit , Sadhana S. Rayalu , Nitin K. Labhsetwar

Adsorption potential of metal oxide (lanthanum, magnesium and manganese) incorporated bentonite clay was investigated for defluoridation of drinking water using batch equilibrium experiments to gain insight of adsorption behavior, kinetics and mechanisms of adsorption of fluoride ion. The effect of various physicochemical parameters such as pH, adsorbent dose, initial fluoride concentration and the presence of interfering co-ions on adsorption of fluoride has been investigated. The 10%La-bentonite shows higher fluoride uptake capacity for defluoridation of drinking water as compared to Mg-bentonite, Mn-bentonite and bare bentonite clay. The uptake of fluoride in acidic pH was higher as compared to alkaline pH. The equilibrium adsorption data fitted reasonably well in both Langmuir and Freundlich isotherm models. It was also observed that in the presence of certain co-existing ions can have positive effect on removal of fluoride, while carbonate and bicarbonate anions show deleterious effect. The rate of adsorption was reasonably rapid and maximum fluoride uptake was attained within 30 min. The modified adsorbent material shows better fluoride removal properties for actual field water, which could be due to the positive effect of other co-ions present in the field water.

Enhanced Adsorptive Removal Of Fluoride Using Mesoporous AluminaBy Grace Lee, Chao Chen, Seung-Tae Yang, Wha-Seung Ahn

Two different kinds of mesoporous alumina samples were prepared using aluminum tri-sec-butoxide in the presence of either cetyltrimethylammonium bromide (MA-1) or stearic acid (MA-2) as a structure- directing agent, and tested for adsorptive removal of fluoride in water. Both materials contain a worm- hole-like mesopore structure, but exhibited different textural properties: surface area (421 or 650 m2 and pore volume (0.96 or 0.59 cm3 adsorption capacity and faster kinetics to those of the commercial activated aluminas in fluoride removal by adsorption process. MA-2 prepared using stearic acid, in particular, demonstrated an adsorption capacity (14.26 mg/g) and initial adsorption rate (14.6 mg/g min) that were respectively 2.2 and 45 times higher than those of a commercial gamma alumina. The textural features of larger surface area and relatively smaller pore size in MA-2 compared to the activated aluminas are believed to be responsible for this enhancement in adsorption process. /g). These mesoporous aluminas demonstrated significantly improved

Removal of Fluoride from Drinking Water: Analysis of Alumina Based Sorption by Theodora Stewart

Fluorosis, a disease caused by exposure to elevated levels of fluoride in drinking water, impacts
millions of people in both developed and developing countries. It is, therefore, important to
improve existing methods of defluoridation. This review discusses the sorption of fluoride to
alumina sorbants, a widely used defluoridation filter material. To discover significant factors that influence the sorption process, and to thus learn how this technique might be enhanced, a
select group of peer reviewed sorption studies were compared. As a result of this analysis, it is
clear that fluoride sorption to alumina sorbants is a complex process in which differences in
surface morphology, pH, temperature, fluoride concentration and the presence of other major
ions such as sulfates and bicarbonates interact to produce a wide range of reported specific sorption values

Drinking Water Distillation Systems

 Based on the study "Evaluation of Total Dissolved Solids as a Surrogate Parameter for the Reduction of Inorganic Contaminants by Distillation Systems," conducted for the Water Quality Association by NSF International, 1991, TDS may be used as a surrogate for verifying the reduction of arsenic, barium, cadmium, chromium, copper, lead, nitrate, and selenium to equal to or below the MCL when tested in accordance with annex B. (See annex F for rationale and supporting data.)

Link : http://standards.nsf.org/apps/group_public/download.php/1413/62i15r1.pdf

Investigation of Defluoridation Options for Rural and Remote Communities by Amy Dysart

Fluoride primarily produces effects on skeletal tissues (bones and teeth) and has a narrow range between intakes that cause beneficial and detrimental health effects. Elevated levels of fluoride (>1.5 mg/L) in thedrinking water occur in a number of parts of the world and often have significant adverse impacts on public health. In the Northern Territory elevated levels occur in a limited number of groundwater supplies, resulting in an increase in the prevalence of dental fluorosis in the affected population. The investigation focused on the identification of a cost effective, robust and low maintenance defluoridation system that may be implemented in these rural and remote communities. Batch adsorption experiments utilising activated alumina, bauxite and hydrotalcite were carried out, resulting in the successful removal of fluoride from natural water samples. Activated alumina displayed the highest removal rate, greatest capacity for fluoride and the smallest impact on the other water quality characteristics, of the three media and was utilised for further equilibrium isotherms and column studies. Activated alumina equilibrium isotherms were correlated to the Langmuir and Freundlich equations indicating appropriate levels of fluoride adsorption from natural waters could be achieved. Water from two communities in the Northern Territory, Tennant Creek and Ali Curung, was successfully treated through column studies, achieving adsorption capacities for fluoride of 875 mg/kg and 1268 mg/kg respectively. The regeneration (and reactivation) of the column was carried out using 0.1 M NaOH and 0.1 M HCl, which resulted in a decrease in adsorption capacity of the activated alumina with each regeneration.

Link : https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjk08q9grHMAhWEjo4KHW6_DUIQFggbMAA&url=http%3A%2F%2Fwww.waterra.com.au%2Fpublications%2Fdocument-search%2F%3Fdownload%3D75&usg=AFQjCNEckYrilzjdofQ294sLhmw8uri1_w&sig2=O7IyCOQIeoodV2grnOtK6Q&bvm=bv.120853415,d.cWw

Guidelines On The Conditions For Using Activated Alumina For The Removal Fluoride From Natural Mineral Waters And Of Spring Waters

Commission Directive 2003/40/EC sets up a maximum limit1concentration in natural mineral waters (NMW); that provision comes into application on 1January 2008. From this date, NMW which do not comply with this requirement can nolonger be marketed unless they have undergone a treatment for fluoride removal inaccordance with Article 4 of Directive 80/777/EEC.Pursuant to Article 4.1.c) of Council Directive 80/777/EEC, such treatment has to:- comply with conditions of use to be determined after consultation of the EuropeanFood Safety Authority (EFSA);- be notified to the competent Member State authorities and be submitted to a specificcontrol of these authorities.The fluoride removal on activated alumina was evaluated by EFSA which issued on 27September 2006 a favourable opinion on the use of that treatment in NMW and spring waters.It was not possible to determine on a regulatory basis the conditions for the use of thetreatment mentioned above before the date from which the maximum limit of fluoride shall becomplied with.Pending adoption by way of regulatory instrument that should be done as soon as possible, thepurpose of the present guidelines is to provide the operators concerned as well as the MemberState control authorities with the conditions of use of the treatment. These guidelines havebeen agreed with the Standing Committee on the Food Chain and Animal Health at itsmeeting of 14 December 2007.It has to be noted that no other treatment for NMW de-fluoridation has been assessed andvalidated by the EFSA. Therefore, the treatment on activated alumina is the only usabletreatment in that purpose for both natural mineral waters and spring waters.(ML) of 5 mg/l for the fluoride

Hydrated Cement: A Promising Adsorbent For The Removal Of Fluoride From Aqueous Solution By S. Kagne, S. Jagtap, P. Dhawade, S.P. Kamble, S. Devotta, S.S. Rayalu

The present study was carried out to investigate the potential of cement hydrated at various time intervals for the removal of excess F− from aqueous solution by using batch adsorption studies. The influence of different adsorption parameters, viz. effect of adsorbent dose, initial concentration, pH, interfering ions and contact time were studied for their optimization. It was observed that the adsorbent exhibited reasonably significant F− removal over a wide range of pH. The presence of carbonate and bicarbonate ions in aqueous solution were found to affect the F− removal indicating that these anions compete with the sorption of F− on adsorbent. The equilibrium adsorption data were fitted well for both the Freundlich and Langmuir isotherms and the adsorption capacities were calculated. Comparative studies for F− removal in simulated and field water show relatively higher F− removal in simulated water. XRD and SEM patterns of the hydrated cement were recorded to get better insight into the mechanism of adsorption process. From the experimental results, it may be concluded that HC was an efficient and economical adsorbent for F− removal.