 Hello everyone, welcome back to a new session on dentistry and more today we have a continuation of fluoride topics that is defluidation techniques. So in this video I will be explaining about various defluidation techniques which are commonly used by the Indians that is 15 out of 30 states have affected with fluorosis. So the common practices which are seen in India is explained in this video. So I have explained you about fluoride as a double H sword in my fluoride toxicity video because once it is going low it can cause or it can attribute to formation of dental caries and if it is going high it causes fluorosis. So in 1984 WHO guidelines suggested that there should be one PPM for the optimal fluoride one PPM should be the optimal fluoride concentration. So as to get the maximum benefit of it is to prevent dental caries. So if it is a warmer climate the PPM can be low around 0.7.8 and if it is a cooler climate it can go up to 1.2. So the range varies between 0.7 to 1.2 because it is affected with the temperature. So we have already learned the motling because in the history of fluorides we have seen the motel enamel it goes higher the motling and discrete witting will be seen. So if it goes 1, 2, 3, 4, 5 range it causes severe destruction of the tooth. So for your information the highest naturally occurring fluoride is recorded in a lake in Kenya and the lake is known as Nakuru and it has 2800mg per liter that is 2800 ppm. So we are talking about 1, 2, 3 ppm but this lake has 2800 ppm this milligram per liter is ppm. So India has 15 out of 32 states that includes unit territories we do not have 32 states as such it includes unit territories. So 15 of total this states and unit territories are affected with fluorosis that is endemic fluorosis is present for a very long period because groundwater has high amount of fluoride content. So in India we have in USA we have seen the community water fluidations where happened in many cities but in India there is no possibility of community water fluidation because we are suffering from the excess amount of fluorine or the fluorosis. So we are always thinking about de-fluidation not the water fluidation because we are at the other edge of the fluorine because we are getting disadvantage out of fluorine. So mainly the Gujarat Rajasthan, Andhra are the 50-100% of the district in these states are affected in Kerala it is Alopea and Palakkad were affected mostly but in these states have a severe attack of this fluorosis that is almost 50-100% districts are affected. So let us come to the point that is de-fluidation so what we are doing is we are removing fluoride from the drinking water that is the idea behind de-fluidation. So what we can do is either we can remove the fluoride from water or you can go for alternative source of safe water and bring water from very distant sources so those are the things we have but the most convenient and most feasible method is de-fluidation that is remove the fluoride from the water we have. So we have few methods de-fluidation and by definition it is the downward adjustment of level of fluoride in drinking water to the optimal level so we have learned fluoridation is upward adjustment so we are increasing in community water fluidation the upward adjustment of fluoride but whereas in de-fluidation it is a downward adjustment of level of fluoride in drinking water to the optimal level that is 1 ppm. So we have the common methods as adsorption technique, ion exchange technique, precipitation technique and some techniques known as reverse osmosis. So adsorption is keeping some material in the water and the fluoride will be adsorbed to the surface, ion exchange is replacing the fluoride ions by cations and anions, precipitation is just like our water purification method we add alum lime and bleaching powder and precipitate the fluoride by making it a flux. So this precipitation method is the most common also known as an Alganra technique which is almost same as our water purification or the process which we have seen in the water plant the flocculation sedimentation filtration all those procedures are same in this precipitation technique. So water purification is almost same. So let's see one by one first one is adsorption technique it is nothing but the adsorption of fluoride ions onto the surface of an activation we put some active agent into the water and get the fluoride adsorbed not absorbed adsorbed on the surface. So the material used are activated alumina, activated carbon and bone char, bone char is nothing but bones of this dead animals so it can it has a property to adsorb this fluoride okay so activated alumina which is launched by UNICEF in rural India because rural India is mostly affected with fluorosis. So alumina can be inserted into the water and it adsorbs the fluoride but the most problem faced with this alumina application is adsorption of fluoride only at specific pH range so we have to check the pH range whether it is suitable for this alumina application or not and there is always a pre-post pH adjustment of water. Water should be at a proper pH for this alumina activation or alumina application and there should be frequent activation of alumina is needed which makes the technique very expensive so once we use alumina it gets replenished it needs to be replenished the active ingredient will be lost after a period of time so it needs to be replenished or frequent activation is required so these are the disadvantage of alumina so bone char as the same process bone char we put into the water and it absorbs fluoride but the problem is it depends upon the temperature and pH of the water but it is economic bone char are economic because it is maybe available not like activated alumina but the main problems are it can harm the bacteria and it is unhygienic method and it is very technique sensitive and the biggest problem in Indian scenario is the cultural and religious objections we take once of the dead animals it may cause problems considering the cultural sentiments so the next thing in adsorption technique is big pieces column so it is almost like activated alumina so it has a agent compound is the compound which is present in the brick column is alumina oxide which absorbs fluoride and also mud pots also can be used to remove fluoride so water which is kept in mud pots the mud pot will receive or it absorbs the fluoride and it is one of the common method which is used in the rural part because of its economic point and it is commonly used commonly accepted in rural community because mud pots are easily available and it is cheap so there are some natural adsorption adsorbants like drumstick tree seeds of drumstick tree roots of vetiver grass and tambourine seeds the MS swaminathan research foundation that is MSS RF had shown that this drumstick seeds to have a remarkable deflugation efficiency which is higher than that of activated alumina so which is all natural adsorptions we have drumstick seeds roots of vetiver grass and tambourine seeds so these also can be used as an adsorbent so these were the adsorbing techniques so we had seen this natural adsorption adsorbents and mud pot brick pieces then the bond charge activated alumina so the next we have ion exchange method so ion exchanging method is using of synthetic chemicals namely anion and cation exchange so the problem with this technique is it is very expensive and economical in Indian scenario because Indian scenario this pleurosis is mostly affected in the rural areas and they cannot afford this type of equipments and this ion exchange techniques they're all convenient with the adsorbing techniques till the nalgonda technique has come into practice so one of the ion exchange technique the compound used is carbion it is a cation exchange resin so it can be used on sodium and hydrogen cycle so it exchanges the cation whereas a defluron 1 and defluron 2 are different one so defluron 1 has it is a sulfonated sawdust which is mixed with 2% H alum solution the defluron 2 was developed later to overcome the problem of defluron 1 it is sulfonated coal using alumina solution okay first one was sawdust whereas the second one was coal both are sulfonated so that was a very expensive method this carbion defluron 1 defluron 2 the ion exchange method so the ion will be exchanged either the captain or anion the ion of this fluoride compound or this fluoride will be because fluoride and ever stays as an ion it always exists as a compound so the product we apply will replace a scion or it exchanges scion and reduces the fluoride availability or the presence in the drinking water so make it to a drinkable condition so this is not used because of its expensive nature and the most common method we use is a precipitation technique so disadvantages of ion exchange agent and adsorption techniques we have seen because there need to be a necessary flow system and it is often difficult to arrange if there is no pipe to water supply if people are taking water from the wells or rivers or something like that ponds or such water supply this is not possible the two methods which I explained already are not run with this well system there should be a flow system that is it should go through the pipes and this equipment should be connected to the pipes and there should be and this is an active agent so there should be frequent activation of the agents there should be replenishment of this agents otherwise the water won't be get the fluidization but the precipitation methods are based on the addition of chemicals such as coagulants and precipitating the soluble fluoride as insoluble fluoroappetite okay so it's just like what we have seen in water purification method the big tank we add alum as a coagulant and it coagulate the impurities and the flokes are getting sedimented and it removed from the bottom of this chamber and then it goes through the filtration it's the same principle is being applied in Nalconda technique except some extra agent will be added here the Nalconda technique of fluidization is almost same as water purification and it was invented by Neary that is national environmental engineering research institute in Nagpur and it was by Nalke et al in 1974 it was very economical and simple method so why this Nalconda name came because Nalconda is a district in Andhra Pradesh where they used this technique as a indigenous method later this institute has taken up this method and commercialized and they started building this plan for these rural people but Nalconda is the area where this technique was in its primitive fashion so they started it so the name was given as Nalconda technique Nalconda is not in Nagpur it is in Andhra okay so what they're doing is they are adding sequence of sodium aluminate that is alum lime and bleaching water to the fluoride water then do the flocculation sedimentation and filtration just like our water purification so in most commonly we add alum to the water purification plant or water purification the first step here we are adding lime and bleaching water in a sequence so that is a difference in between this water purification and Nalconda technique so it can be very useful for domestic and the community water supply so this is just a flowchart what we are doing is lime alum and bleaching water will be mixed to the first point of entry and there will be a rap mixing this is flocculation then there will be sedimentation this sediment will be removed from the bottom of the chamber and this goes to the filtration so filtration slowly it gets filtered and it goes to a clean water tank so the process is almost same as water purification only thing is it has a different reagent lime alum and bleaching water so mechanism is it will commonly run for a 22 liters of water the first we do rapid mixing that is coagulant will be added to this water and then 30 to 60 seconds with a speed of 10 to 20 rpm the coagulant is rapidly mixed so it gets uniformly dispersed so it start getting microflogs of fluoride because of this chemical coagulant then flocculation is the second stage where it is rpm is 2 to 4 the beginning it was 10 to 20 now it is slowly run for 10 to 15 minute the rapid mixing was 30 to 60 seconds the flocculation it is slowly to the rotation and it started forming the flocs because of this coagulant the fluoride compound will get become will become flocs and it's starting sedimentation so due to this gravitational force this particles will be sedimented at the bottom and it will be removed okay as we have seen in the diagram okay so we add here we do the rapid mixing then for flocculation this is 10 to 20 rpm 2 to 4 rpm this is for maybe 1 minute this is for 10 to 15 minutes then this it goes to sedimentation this is a sedimentation tank here it is slowly slowly for 10 to 15 minutes and 2 to 4 rpm then this sediment this floc flocs are removed from here because flocculation happened here and the flocculation flocs are removed from here then it goes to the filtration and filtration and finally we get the clean water so filtration is same like our water purification plant so it get filtered and we can send it for the domestic supply so maintenance is very cheap it is like 1.6 lakh for a 250 population and only we need 50 stainless steel filters and it is costing around 35000 so the main advantage it's its low cost of investment and low cost of maintenance so the biggest advantages are there is no need of regeneration of media which we have seen in the adsorption techniques no handling of caustic acids and alkalis the chemicals are required are readily available and it can be used for domestic use economical symbol design construction we can use a very large quantity of water which is very efficient removing fluoride from high levels and very little wastage of water and needs minimum mechanical and electrical equipments there is no need of energy only need muscle power semi-skilled workers also can be used so the biggest disadvantage is if the total dissolved salt exceeds 1500 milligram per liter we need to do a prior desalination and hardness of water also matters if it is 200 to 600 it requires precipitation softening and if it is beyond 600 milligram per liter it needs becomes a cause for rejection or adsorption of desalination so there will be a high amount of sledge compared to the other methods in algonoma and there is a requirement of a large amount of alum so indications should be total dissolved salt it should be less than 1500 milligram per liter total hardness should be 600 below 600 this should be below 1500 and raw water fluoride should be between 1.5 to 20 that is 20 ppm modifications are like poly aluminum chloride is another compound poly aluminum hydroxy sulphate also can be used and the other methods are reverse osmosis electrolysis or electro dialysis are the physical methods that are tested for deflutation so these methods are also can be used for a very small amount of water so reverse osmosis is like we use hydraulic pressure exerted on one side of a permeable membrane we have seen it in our nr classes what is osmosis what is reverse osmosis we keep a semi permeable membrane and apply hydro hydraulic pressure which forces the water across the membrane and leaving the salt behind so leaving the salt of fluoride behind and get the clean water on the other side in electro dialysis the membrane allows the ion to pass but not the water okay so our idea is to remove the fluoride from this water so we can use a reverse osmosis escaping semi permeable membrane or in electro dialysis the ions will be passed and the good water will be left out and electro dialysis is also very expensive and intensive procedures but it is very rarely used all these reverse osmosis electro dialysis techniques electrolysis also it is a process with adsorption of fluoride with freshly prepared aluminum hydroxide which is generated by anodic dissolution of aluminum or its alloy in electrochemical cell we have learned in chemistry what is anode what is cathode what is electrolysis so once electricity passes this ions moves to anode and cathode so that procedure also can be used to remove fluoride from water biggest advantage is it doesn't need any chemical and no need to pre and post treatment low volume of sludge but it is there is a requirement of electricity so that's all about defluidation techniques because like I said 15 out of total Indian states are affected with fluorosis so we are into the action of defluidation not water fluoration because we are to remove the fluoride from the water to get people a palatable or portable drinking water so that's all about defluidation techniques the most commonly used in algondae technique and adsorption techniques are there this is a precipitation technique and ion exchange methods are very expensive and some other techniques we have seen reverse osmosis electrolysis like that so that's all about defluidation techniques I'll come up with another topic then just general thank you