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Major Issues Regarding the Application of Industrial Wastes

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So first we start talking about the industrial byproducts the question is that what are themajor issues which are bothering us and before I start using the industrial byproducts asa geomaterial man-made geomaterial.The first thing is that identification of the application is not very clear.So we have to create this we have to create the applications for a certain industrialby-product.You must have realized that.I have been talking about mine tailings, I have been talking about the mill tailings,I have been talking about the slags which are coming out of the industries, red mudI think I discussed about in one of the lectures which is coming out from the refineries wherethe alumina is being extracted from the bauxite.Similarly, the minerals which are being processed from the mines these are major issues likethe volumes of industrial byproducts must be in trillions of tons all over the worldand humanity is facing a big issue.Now what to do with this and this is where the identification of the application becomesvery important.Second is I will be requiring the key properties of the geomaterials before I can use it inconventional geomechanics we talked about coarse grained material, fine grained materialand we differentiated between the soils.So something of this sort has to be done in case of industrial byproducts also that wehave to understand their key properties.What are the key property then how to use that property as a positive of the materialstrength of the material and at the same time I have to understand what are the negativesor the weaknesses of the material?As far as weakness is concerned this could be a threat to environment geoenvironmentall right so we have to make sure that the material when it is utilized for any applicationshould not be contaminating the geoenvironment that is the main area main thing to discuss.We had also talked about the environmental sustainability.Sustainability is the key word in today’s society contemporary world you know we wantsustainable solutions we are discussing about this in the previous lecture also how to makea sustainable situation and talk about this in details today and then what are the testingprotocols which can be developed in the laboratory.So when you are treating a material as a new material you have to understand how this systemis going to behave under a given circumstance what will be the response of this materialto different energy fields.So we have to perform laboratory experiments to develop the protocols sometimes from laboratorywe might have to take these results to the field also then we have to model the engineeringbehavior and this engineering behavior can be modeled in the by conducting suitable laboratoryexperiments.Shear strength is a good example of you know what is the engineering behavior of a geomaterialcompressibility would be another consolidation characteristic would be third one compatibilitywould be another permeability could be another engineering behavior plasticity index couldbe another engineering behavior heat migration through the material could be another engineeringbehavior all right and so on.Then the question is that when I am selecting a material major issue is the constructabilityissues and how the system is going to perform you remember long term monitoring which wewere talking about some time back whether the system can be constructed or not.It may so happen that the industrial byproducts which you are using are lighter than the nativesoil or at the same time they could be heavier also.So when we talk about let us say slags where the specific gravities are extremely high3.5, 3.6, 3.7 as compared to these soils which are of 2.6, 2.7.Then the question is how to balance these two systems you know the industrial byproductssitting on the soils and this is where the geo mechanics of the contacts interactionagain starts.So, field performance is a big issue, constructability is a big issue long-term performance is anotherquestion how the system is going to perform in the long run alright.So, if I am utilizing the dredge materials for making the roads.I was talking about in the previous lecture there are beautiful examples of land creationin the country and we discussed about some of the projects in the last class.So, the question is that if a system which is with the geomaterial which are not similarto the naturally occurring your materials if I am using them for doing some engineeringhow would they behave in the long run particularly their decay decomposition deformation alrightdisintegration.So all these terms become very important when we talk about the long term performance.So this is a big challenge I am sure you must be realizing that I have opened up the pandorabox and these questions have to be answered by scientists and by the industry guys bythe planning commission guys in the country and you know each and everyone in the societythen comes the regulatory constraints.“Professor - student conversation starts” sir my question is like can we accommodatedecay like can be allowed decaying of the material or we always have to shield againstdecaying see previous lecture I gave you an example where I wanted to shield the materialagain decaying by cutting off the oxygen supply.But there could be lot of situations like MSW municipal solid waste, landfills whereyou want them to get decayed.If I have to use this for a engineering purpose let us say for a road construction or a railwayembankment, then that I cannot afford like my question is I cannot afford to correct.So then I think you have to do something of the sort which I told you in the previouslecture that you have to shield it against the environmental actions and decay whichis induced because of the environmental activities “Professor - student conversation ends”.So regulatory constraints become very important before you do a planning of how you are goingto use the material and most of the time these regulatory constraints are from the pollutioncontrol boards or from International Atomic Energy if you are dealing with the nuclearwaste IAEA International Atomic Energy Association.So when you are talking about the nuclear waste these type of agencies are there.Otherwise domestic waste, industrial waste CPCB, MoEFCC in India these are the organizationswhich take care of this a lot of NGOs which are taking care of the activities of the governmentand the industries and they are trying to put them on the right track.So regulatory constraints could be of different types then comes the question of sustainabilitywhich is very big issue how the system which you are trying to develop is going to be sustainableor not.So I am sure you can add lot of other issues here in this list and make it more robustall right.The volumes of the industrial byproducts whether they are available or not for a particularapplication their transportability is another question and so on.So when I was dealing with the airports design and the reclamation in the sea particularlyin Bombay city, I wanted always to bring this material from other parts of the country butthen there are issues related to the economics time and so on.So the huge reclamation which has been done to create Navi Mumbai International Airportand I was a consultant.So if you look at the sustainability cycle this is how the sustainable development lookslike and on this concept some of my students have already worked.So please check out the thesis by the Prathyusha Jayanthi, Ganaraj who is still working onthis, but he has published papers where we have talked about the utilization of K Ganaraj.So where he is talking about how to utilize the mill tailings mine tailings for sustainabledevelopment read these papers which have been published in very good journals.So if we talk about the sustainable development what it is we have geoenvironment and basicallythis is the soils, rocks, ground water and mining activity is number one it leads theentire issues associated with what we are talking about so when you do extraction ofminerals by mining you do processing of the minerals industrial activities and you produceend products by products.These are known as industrial byproducts which you are talking about these industrial byproductsare unsafe when you leave them unattended.We have discussed about several issues stability is an issue, leaching is an issue, fire isan issue, mosquito breeding is an issue and so on.So what you have to do is you have to process these byproducts and if you can utilize theirpotential you know and you can activate them you can use them sometimes for ground modificationand improvement also and then what I can do is this type of an activity is a sort of areplacement of the material which you mined out and whatever left over again it is goingback to the geoenvironment.So this becomes a complete cycle of sustainable development.Now this concept seems to be very interesting right now and, in our lab, we are activelyworking on rejuvenation of you know soils which are barren, or which have low fertility.Idea is by utilizing the industrial byproducts you can create a situation which could bea win-win situation for everybody.However, a lot of research is required in this area.So if you go back to the history of civil engineering pozzolana is something which isknown to everybody.Mostly pozzolana is the material which has come from a place in Italy called Pozzuoliand the property is that if you add few drops of water it sets it becomes hard cement isa pozzolana all right fly ash is also pozzolanic material depending upon its fineness its activityand so on and the percentage of life in it.In Hindi in the northern belt we call it Surkhi I do not know what about the local languagewhich you use in other parts of the country.So if you compare the activities of the natural volcano and the man-made volcano, I thinkyou will realize that this processes are quite similar.Therefore, yesterday was talking about the industries which are emitting lot of dust,ash all right fumes in the environment and what volcano does?Volcano also does the same thing there is a lot of similarity between what nature doesand what we are doing as far as the influence to the geoenvironment is concerned.The issue is simple the sediments which come out of volcanic activity which they are depositedafter the lava is formed or before the lava is formed could be rocks or could be the finedust which is very fertile and here whatever we are creating in these industries is thesort of a fly ash, slags they could also be nutritious.And if you go through the published literature you will realize that lot of work has beendone to show that fly ash have lot of nutritional value and there is no surprise because ourvillagers and the farmers are quiet intelligent and they have been using ash for rejuvenatingthe lands if you remember this is a common practice after every crop they incineratethe residues they mix it with the soil they make it more fertile because after incinerationNPK gets balanced in the soil nitrogen phosphorus potassium magnesium and all sorts of you knowminerals.So this happens to be an interesting material on which people are doing research of coursethis becomes an interdisciplinary area where a lot of bio-geotechniques and material sciencegeotechnical engineering applications, concrete technology, you know process engineering isbeing taught about.I am sure you must have come across different types of application of the fly ash.So normally people have used the fly ash for stabilization of roads increasing their CBRpavement and subbases their properties.People have used fly ash for reducing the swell pressure of the soils so by additionof the ash into clays and particularly the clays are swelling type you are neutralizingthe swelling effect as well as very high liquid limit and plasticity index.So this is a very interesting application which people have been practicing since longand once you do the plasticity modification the material becomes better for compaction.CBR modification is one of the good examples of how the fly ash have been used for creationof pavements and nowadays they are using this material as the fill material for embankmentsparticularly RE wall.So in the absence of the granular material what people have been doing is they take thegranular fraction of the fly ash which is lying either in the ponds which are knownas lagoons or they filter out the coarse fractions which is sandy silty fraction or sometimesthe bottom ash which is available in the hoppers is utilized for this purpose.So I have been associated with the big business houses of the country where we have establishedthat the fly ash which is lying unattended can be utilized as a sustainable constructionmaterial for different applications and good example was I got a project from BSES, nowits reliance energy and the question imposed was that can be decant the fly ash ponds toaccommodate the fresh ash which is coming out of the units all right.So these type of discussions and these type of engineering practices are being done inthe country these are good examples of the application which you were talking about peoplehave used fly ash for creating different types of cement mix also and fly ash is used increating the PPC also Portland pozzolana cement by blending it with the OPC.So this is prehistoric lot of research has been done nothing but subsequently when Italk about the material characterization, I will show you what type of chemical processeswhich we have given to the fly ash to convert it into much more value-added material andthis is where we will be talking about the cation exchange capacity enhancement of thefly ash by hydrothermal treatment.