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Module 1: Multipoint Machining Processes

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Bio-degradation Studies of Cutting Fluids

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Video 1: BiodegradabilityToday we are going to study about ah one of the important concepts of cutting fluid, howwe can test the Biodegradation of various cutting fluids?Overview of today's lecture we will see why the biodegradation is important and what isah BOD and COD and all those thing biological oxygen demand, chemical oxygen demand andall those things. We will see also what is HRT hydraulic retention time and we will seewhat is ammonia and nitrites, nitrates in the form of the one of the forms of the cuttingfluid, how it is going to effect the operator as well as the environment and all those things,we will see in this one ok biodegradation .So, at last we will compare with respect to mineral oil in some of the places we alsosay that it is called as a CMO that is called commercially available or the commerciallymineral oil, commercially available mineral oil or commercial mineral oil and we willcompare with bio cutting fluid, how these will effect and all those things we will see?So, on an average we compare the biodegradation studies of commercially available mineraloils such as servo cut s is what we have used. And some of the alternatives mineral oilsare available by servo itself and Hindustan petroleum some many many companies, whichare ah supplying these types of mineral oils. Bio cutting fluid which is also we have takenin this ah studies a ah commercially available ah bio cutting fluid.So, comparison study we will see ok . So, pollution by the cutting fluid if you seethe pollution normally in the emissions chapter, when we are studying there is a problem onthe system plus surroundings. The surroundings what we are going to deal today; especiallyfrom the point of ah water pollution which we are going to study today ok.The pollution is introduction of contaminants into the natural environment just whateverthe contaminant that ah in the daily life one come across, if you are we just releasinginto the normal atmosphere that is called pollution pollutants came from chemical substancesor energy such as heat light or noise and all those things ok .So, currently what we study about in this particular ah lecture is about ah chemicalsubstances. If you see the picture the figure 1 and ah figure 2, figure 3. So, these 3 figuresthe figure 1 and figure 2 shows, how the pollutants are polluting the water pollution or the nearbywater bodies? And this is a drastic effect and if you, ifsomebody do or some companies do it is a unhealthy practice from the point of marine as wellas the people who are living surrounding to the those water bodies.The third one is which we have seen also in the cutting fluid emission that is calledah land pollution or soil pollution ok . So, if you just dig into at certain part of acompany at some corner and just to dump the cutting fluid this is ah you just ah throwit on a open land wherever, which is nothing or nobodies land or it is it if you on a publicland or something. So, it will cause us lot of ah land pollution or the soil pollution. Mostly todays lecture revolve around the waterpollution . If you come across problem due to cuttingfluid, if you see the cutting fluid or petroleum based some of the fluids which you can seein this ah figure 1 . So, cutting fluid or some of the mineral oil it is ah it is mixedwith the normal water body and it contaminates as well as, it will affect the complete marineacquire system; like fishes, prawns, ah those organisms that live on these one like birdsand all those things if you see in the second picture . So, these are all the system marinesystem that will effect on it ok. So, one should take care about what shouldbe released and what should not be released that is what we will see . If you releasebefore it is it has if you release those things, which are dangerous to aquas life; obviously,it will create lot of problems to the aquas life not only to the aquas life it also destroyor create problem to the the people or the organisms or any other living things thatwill depend on those aquas systems. So, it is not a good practice to release thesetype of things . If you see the human health effect normallythe air pollution, water pollution, and soil contamination, how these are going to effectthe human? If you see the air pollution this is the air pollution this is going to affectin the nerve damage from the point of lead, volatile organic compounds it will createlot of cancer, skin irritation and all those things and another carbon monoxide these arethe things that will pollute the atmosphere and causes lot of problem to the operator. If you see the water pollution how the waterpollution the water pollution, bacteria, parasites, chemicals these are all goes and destroy thegastroenterology system that is your stomach gastric problems, acidity problems, thesetype of problems also you come across ok. If you see the soil contaminations so, soilcontaminations will create lot of problems like; cancer risk, nausea, and skin theseare the some of the problems which you come across.So, todays class since we have already seen in the previous lectures in the cutting fluidemissions chapter, there we have seen air pollution effects . Now we are going to seethe water pollution and we do not have much problem or major issues with the land, becauseah land it ah contamination is the only slight problem ok. That will have it is own effectscurrently the second major that will be what we are going to see is water pollution, howthis water pollution comes with respect to the cutting fluid and all those things wewill see . So, degradation normally there are many typesof degradation is there some of the people you may be heard of hydrolytic degradation,chemical degradation is there biological degradation is there and all those things ok .So, degradation means if there is any particular chemical or a polymer or any material is thereit will degrade with respect to time, in any means like chemical degradation, hydrolyticdegradation, biodegradation, many degradations are there .For example, if you see I am continuously telling about the biodegradable polymers areplacing ah it is own importance in the nowadays world, because ah it is starting from thetea cup to the bio implants. What is it will degrade inside the body? If you are puttingthe implant inside the body normally, it will also degrade assume that poly lactic acidis there it will degrade into lactic acid ok. That is one type of degradation.What we are seeing today bio degradation is nothing, but degradation of pollutants orany substance by microbes using materials as energy of the source. So, that means, thatthese microbes will take as it is one of the sources of their energy ok. Like Enzymes,Maine, Bacteria, virus, these are all are called as microbes ok.Bio Debigrade biodegradability simply means it is consumed by the microorganisms and returnto the compounds, which are found in the nature; that means, these microorganisms just to takeas their energy source like carbohydrates or something .So, it will take and it will release another thing that are biodegradable are which arenaturally found on the earth this is nothing, but the biodegradation .So, biodegradability the chemical breakdown or transformation of any substances by themicroorganisms like bacteria, fungi, are known as biodegradation ok. The ability of substancematter biodegradable known as biodegradability there are 2 terms, which are familiar withrespect to biodegradability that is primary degradation, another one is ultimate biodegradationit. So, primary biodegradation deals with change in chemical or physical property ofthe substance caused by microorganisms activity ok .So, ultimate biodegradation normally it is complete utilization ok. In the primary ahbiodegrading we can see preliminary experiments only or preliminary biodegradation whetherit is degradable or not. We can from that experiment, we can also expect it can be completelydegradable or not only thing we can expect or we can predict, but ultimate degradationis the experiment that one has to conduct or you have to do some of the mathematicalcalculations. So, that you can say quantitatively how much is biodegradable? Whether it is 99percent biodegradable or whether it is ninety percent degradable or so on.In the ultimate bio degradation complete utilization of the substance result in the conversioninto methane or carbon dioxide, water and biomass as well as minerals and salt . Youcan convert into this type of things in the ultimate bio degradation . So, there are fewterms that you should be familiar . So, dissolved oxygen normally dissolved oxygenin any liquid normally it will contains, in any liquid it is very important element tomeasure it is life cycle, dissolved oxygen, oxygen will be there always in the liquidin the dissolved form. So, how the fishes survives their life and all those things youknow the mechanism at the early stages of our carrier normally like ah 6 to 10th inbetween normally we study all these mechanisms and all those things.The first term that I am going to give you is biological oxygen demand that is calledBOD which I was explaining in the overview of today's lecture . It measures only thebiodegradable part of organic matter of the substance, assume that I have a particularsubstance this BOD tells me how much e biodegradable part is there that is only it will says non-biodegradable part it would not deal with .
Video 2: Characterization of Bio-Cutting FluidSo, if you see the materials normally in ourcase I have already told we have used the equivalent bio cutting fluid and the secondone is commercially a commercial mineral oil. These are the 2 things we have used the testis carried out ah for these 2, if you see the characterization of bio cutting fluidemulsions and the commercial mineral oil. Normally since you have seen already BCF 8,BCF 10, BCF 12, that is BCF P stands for pure this stands for pure this stands for pure.So, emulsions are taken at the same time pure also is taken .You may get the doubt why you are going for this F 10 to 12 this is already shown youin the previous classes, where thermal conductivity as well as specific heat is measured and these8 to 12 are giving better results. Any, how I can show you and I will come backyou to the previous slide, if you see the emulsions the emulsions are made with 1 isto 2 1 to 1 is to 20 that you can see and KD 2 2 probe is measure you used to measurethe thermal conductivity of the cutting fluid, as well as specific heat of the cutting fluid.From these 2 graphs what we got is 10 to 12, if you see after 8 it is giving approximatelybetter results that is why this range is considered in that one that is called BCF 8, BCF 10,BCF 12, that is why from this it is considered in the previous slide.Let me come back to the slide. So, if now you got it how BCF ah 8 and 10 8 to 12 arecoming . So, p H value p H value is ah approximately BCF is having very less it is near to thenormal that is 7. So, density viscosity at 40 degrees flashpoint these are the some ofthe details that are given and if you see the mineral oil it is about 9.05 p H, theBCF 10 and 12 since the water content is increasing the p H level slightly is increased here,the viscosity of the fluid the normally if the viscosity of the emulsions is very good. If you see here compared to the pure amount of bio cutting fluid as well as mineral oilso; that means, your emulsions have better flowability and capillary action will be good. So, at the same time flashpoint also if yousee the bio cutting fluid has a very good value and this followed by the 8 10 and 12and the flashpoint for the mineral oil is too low; that means, from the point of ah5 accident point of view also bio cutting fluid gives you better results ok . So, thisis what ah you have seen ah in the previous one where you want to move why why you wantto move to BCF 8 to 12 . So, primary biodegradation test primary biodegradationtest is done for the BCF and MO it is plot for BOD 5 bar COD ratio that is for 5 daysthe BOD and COD is calculated and the test is ah plotted between percentage degradationthat is we what you have seen BOD by COD gives the percentage degradation. And with respectto incubation time the incubation time as I said incubation time is done for 5 days.If you see here percentage degradation of BCF is approximately 40 above 40 percent andour percentage degradation of this commercially mineral oil is the maximum at the 50 yearis about 10 percent. But if you see here it is about more than40 percent, like it may be 41 or something. So, after 5 days if you see BCF was 41 percent,but MO was 10 percent. So, from this what one can infer we will see in the upcomingslide? Taking into the consideration what is theinference from the graph is if the 5 days window the mineral oils cannot be degradedas readily as biodegradable 5 days window requires, degradation pass level is 40 percent.If the biodegradation that is BOD by COD if it is 40 percent or above, you can qualitativelysay that this particular material is biodegradable. If it is less than that 1 it cannot be degradablewithin 5 days BCF is 41 percent. And, however, it mineral oil is 10 percent this, becauseBCF contains degradable organic matter , but the MO is dominating by non-biodegradablevolatile or fixed solids. Because of this one the biodegradability of bio cutting fluidis higher compared to the mineral oil, mineral oils are dominated by the non-biodegradableparts . If the BOD by COD ratio that is BOD 5 by CODratio is 40 or more it is you can qualitatively say that it is completely biodegradable completelymeans you can go up to 95 96 percent and all those things. However, if the value is lowerthan 20 percent; that means, that greater amount or unoxidisable organic matter; thatmeans, that you cannot degrade these things that . In the previous graph the inferenceat the bottom line you can draw ease that, if it is more than 40 percent or equivalentto 40 percent that you can degrade completely or mostly you can degrade, if it is less than20 percent; that means, that it will be dominated by non oxidizable or non-degradable part means,our mineral oil which is supplied by many of the petroleum companies is non-biodegradable,but if you can purchase the biodegradable thing that will be good from the point ofdisposing . The another point which you have to consideris BOD 5, that is the 5 days preliminary experimentation that one did cannot provide complete informationabout the total bio degradation, but it can give you a preliminary idea saying that youcan degrade mostly or if not degrade from the percentage like 40, above 40 percent orbelow 20 percent .
Video 3: Hydraulic Retention TimeNow, we come to a new term that is calledthe hydraulic retention time . So, hydrolytic retention time tells about the ultimate timeto degrade ok . So, hydrolytic retention time is a measureaverage stretch of the time that is soluble compounds remain in a constructed by a reactor;that means, what I mean to say is from the see statement you may not get much idea, butlet me say something, assume that the government specified that you should have the BOD orsomething like 200 . So, assume that my cutting fluid has 12 100ok, I cannot dispose because it has to come to 200 then only I have to dispose, in a bioreactorif I am testing the time required to bring my degradation or the BOD from 12 100 to 200the time span is nothing, but hydraulic retention time if my time span is less; that means,that the reaction can be done at less; that means, that the it can be done at faster rate. So, ultimate goal what I am looking at fromthis HRT is how much HRT will be less for the fluid. So, both the fluids will checkwhat is the HRT? Why the HRT analysis is required, despite having high biodegradability ecofriendlyand maximum possible ways of bio cutting fluids are not allow to dispose directly in the sewage,because of high carbon oxygen demand and NOx emissions, which effect the animal. So, theseare the problems that are called the high carbon oxygen demand . So, this is the oneother one is NOx emissions is another one. So, what one has to do is HRT needed to findout the amount of time in which biological microbes will reduce COD and emits less NOxfrom the bio cutting fluid in a aero[bic]- batch batch reactor ok, that mean that ouraim is to reduce the COD and then you have to dump and also reduce the NOx quick andthen just you dump it. So, that is what HRT deals about .So, simply the experiment if you see here you take the 2 samples that is ah BCF andah commercially mineral oil you just aerobic mix culture of the microorganisms from wastewater, phosphate buffer, trace metals, all things you need . If you see this picturethere is a mineral oil is there as well as a bio cutting fluid is there commercial mineraloil you can say and BCF is there a pump is there to pump the oxygen, how the schematicallyif you see these 2, 1 and 2 are represented by this 3 ok .Just you put microbes and you put influent influent is nothing, but the sample and effluentis nothing, but the treated sample are ready for the disposal; that means, what ah thisis the effluent that we have done for the titration. Their burette and all those thingsare there you know this you are taking here with respect to number of days, you are effluentdissolved oxygen will go down. First day there is no dissolved oxygen because there is nomicrobes 0 day you will have the complete dissolved oxygen that is why the value isaround 7.9 8 or something . As you days increases what will happen these microbes will eat awayin the 3 in this one it will eat away some of the dissolved oxygen or it will consumethem of the ah dissolved oxygen. So, dissolved oxygen content gradually decreases in theeffluent . So, what is here we are doing is in the commercialmineral oil as well as BCF you just put the microbes, as well as the water, effluent,influent and all those thing influent is nothing, but BCF in one case another one is mineraloil in another case you just pump to the oxygen, this is a air pump which you can pump theoxygen . So, if the influent is like a carbohydratesok microbes are there in a system microbes are there where if you put influent influentit can take as a carbohydrates, but it cannot continuously take and all those thing becauseit need proteins any human always you cannot consume the carbohydrates only .So, you need proteins, you need vitamins, you need many things, for that purpose youhave to add these trace metals. So, you if you add these trace metals thesetrace metals act as vitamins and minerals. So, that it will consume the amount of carbohydratesthat is nothing, but what influent which is you are adding that is ah BCF or MO and itwill consume with respect to hour like this test is done for 6 hours, 12 hours, 18 hours,and 24 hours analysis is conducted for 5 days each phosphate buffer is also used in thiscase. Just you take the samples before and afterfeeding from the both reactors so; that means, that my a pump is pumping parallelly to theboth one ok. If you see that picture the air pump which pumps the oxygen to MO as wellas the BCF parallelly . So, if you take the thing af[ter]- beforeand after you can measure the COD you can measure the ammonium concentration, nitriteconcentration, nitrate concentration as well as voltage solutes these are all you can measure. So, COD digester is there just you have to take the effluent that is coming out startone after 1 day, 2 day, 3 day, or after hours we will just to take few ml and you just toput in the COD digester and you can get the COD value.At the same time if I want nitrite and nitrate concentrations just you place in the ah UVspectrophotometer as well as visible spectrophotometer for the nitrate analysis for UV spectrum photometerfor the nitrite analysis, you you can use the cuvette and you can put in the UV as wellas visible spectrophotometers and you can get the values of nitrites and nitrates .One thing I want to say here is ah you will get ammonium in the form of ammonium ammoniumcan be in in nitrites as well as nitrates not only nitrites and nitrates, it is theammonium will also contain a some other material ok.It does not mean that if the ammonium percent is very high nitrites and nitrates, whichare dangerous to the organisms, are high . So, that slight also you will come across thereI will tell you the COD ah removal if you see with respect to time, what is here ifyou see the COD removal percentage. If you see the COD removal percentage always yourbio cutting fluid is higher ; that means, that with respect to this particular timeof 24 hours, how much you can remove is with the same time if you take any particular curveassume that I am going to take this particle portion, that is 24 hours because everywhereBCF is having higher value. So, let me consider this way this particularbar graph part . What I mean to say if this is there .
Video 4: Ratio Analysis of Food to MicrobesNow, we will move on to food to microbe'sratio. So, food is most important for anybody. So, how you have to feed the microbes in thelaboratory scale, but how this analogy will move to the practical system ok. So, practicalsystem goes like this if I have a cutting fluid whether it is a bio cutting fluid orwhether it is a a mineral oil cutting fluid just I am dumping it for the biodegradabilityin the nearby water body . So, water body microorganisms are constantonly thing is that it required food ok. Food is a variable. So, that test we will do ifI give you more food what will happen it will eat eat eat and it will also die, if I donot give food what will happen it will also will die. So, you one has to give appropriateamount of food to the microbes, that we will check high amount of food to microbe ratiois characterized by excess food and maximum rate of metabolism . And if with the low amountof food to microbe ratio is known as endogenous phase less food for more microbes ok, resultinglow rate of metabolism the reactor is necessary to provide the favorable environment for theaerobic microorganisms for the decomposition of organic matter, whatever the thing hereit is nearest to values are given here . But if you see the graphs it is very difficultfor the particular persons who work in the laboratory to give micro to Nano liters ofthese ah cutting fluid . So, for that is reason you may see some ofthe variation in the slight variation in the food to microbes ratio, if you see the foodto microbes ratio as the food to microbes ratio is increasing here what will happenyour COD removal is gradually decreasing . What is the phenomenon if the microbes is if youare giving more and more food what is the problem is it is eating eating and they aredying themselves and all those things . So, the COD removal is gradually decreasingthere is a certain value there is a it is a good and later on it is start decreasing,because it is eating overeating overeating may also cause the organisms to die, thatis why the COD a percentage req will gradually decrease after some time ok.Most importantly microbes in the water bodies are constant. So, how much optimum food onehas to give, if you see the picture in the C CM commercially mineral oil as well as theBCF, let me talk about BCF which is a beautiful curve if you see this particular line beforethis one what is happening is your food is less microbes are more in this region yourfood is more, but microbes are less. So, optimum point you have to find. So, that the microbeswill get a right amount of food so, that the system will degrade .Now, I will come back to the first slide of food to microbes ratio, what I said thereis you need to put the food ok . From this particular graph what I want to convey isI have a river body assume that I have a Brahmaputra river. I have the microorganisms in it andI want to degrade my cutting fluid in that circumstances, I want to give the food ifI give less food the organisms will die without degrading my cutting fluid. If I give morewhat will happen if it will overeat and it will die so, I because the organisms are constantbecause I am not controlling the organisms in the river.So, I have to give that particular thing we will simulate or we will do in the laboratoryscale by taking number of organisms, which in the whatever the water body and we tryto give the food if and we will simulate it .So, this is the optimum value where you can give. So, that the better thing can be happenform on the biodegradation point of view from the food.So, kinematic viscosity these are the the important points to be noted and summary ofthe todays lecture is goes like this, we have studied what is biodegradability and whatis degradation and all those things. Then we come across COD, we come across theBOD, in BOD also we come across BOD 5 that is for 5 days and BOD ultimate .So, then we came up with the HRT analysis hydraulic retention time which is normallywe want HRT less. So, we have compared then we have checked for ammonium, in the ammoniumwe have 3 parts which we have checked for the commercial mineral oils as well as thebio cutting fluids one is the nitrites another one is nitrates ok I am not writing full nameok. So, another one is the soluble ah solids basically organic solids ok ok.The ammonium in BCF is high, but that particular ammonium has less amount of ah nitrites aswell as nitrates, but in BCF the amount of organic solvents are high in BCF . So, thatis why even though the ammonium is high that particular graph do not bother, but it containsmajor chunk of organic solids, but BS, but if you go to the commercial mineral oil nitritesas well as nitrates are dominating. So, this is about the todays lecture and ahmost important lecture that I have taken today in from the point of humanitarian grounds. Whenever a person who is operator it is your responsibility as a manufacturing engineerfor the well-being of the operator. So, about the cutting fluid cutting fluidemissions, cutting fluid properties, how to degrade biodegradability, thermal characteristics,rheological characteristics, these are all are covered as a major thing in this particularcourse till now. So, we also see some of the things about thecutting fluid in grinding as well as in other lectures also , but as such the cutting fluidshas or the machining fluids has it is own importance in the present scenario ok.So, that is why I named this particular course as a machining as well as machining fluids.In fact, it is a introduction. So, as the world progresses this will becometoo preliminary and introduction goes to preliminary preliminary goes beyond, that is why I namedit as a introduction to the machining as well as machining fluids .Thank you for the todays class and ah we will see you in the upcoming class .