 the previous lecture we talked about the particle energy field and I described the components of the particle energy field and what are the particle energy fields which normally we talk about and our interest is to understand how the particle or the geomaterial is going to behave in these electric fields. And this is where we also talked about you know possibilities of different new concepts which have to be researched and applied in day to day life. I will henceforth I will move on on more focused areas of environmental geomechanics and particularly the waste. The context is like this that waste is also created by human beings and hence human beings are the best species which should be utilizing the waste which they create and if this happens this becomes a zero discharge concept which is being you know enforced by most of the industrial units where they say it is a zero discharge unit nothing comes out of the industry everything is consumed there everything is recreated there and so on. This is becoming a very interesting philosophy that so called waste which was not having any value how this is becoming a man made resource and if I can convert any of the waste materials into a man made resource that would be an engineering or that would be a technology that would be a very interesting initiative to safeguard the humanity or the mankind against this curse of you know unattended material which is lying on the surface of earth. So, with this in context the subtopics which I am going to talk about would be the waste generation what are the forms of the waste which are normally generated we will talk about the hazardous waste we will talk about the non-hazardous waste and then we will talk about the examples and differences between these two types of waste and then what is the need for characterization of the material because the waste itself is a material as you must have noticed I have written this is a man made resource. So, any resource you would like to understand to the precise details before you start utilizing it or before you create the strategy for its utilization. Now, when we talk about the need for characterization the most important thing is that we would like to talk about the issues which are related to its utilization its reuse its recycling and if I can recover some of the precious materials from the waste. So, this is what the complete cycle is where the waste is treated as a man made resource and the present day circumstances are like this that there is no way except to treat the waste as a resource material and this resource could be for infrastructure development different type of composites development and so on. So, the first thing is that we have to understand what is the generation or what is the source of so-called waste normally we do not use the word waste this is a shift in recent times sometime back people used to talk the unwanted material which is coming out of the industry or from the municipal activities as the waste material. Now we say that this is a man made resource so the more emphasis is on man made resource rather than the waste so nothing is a waste for me in this universe provided I do judicious thinking investigations and then if I develop a approach to utilize it in the most ingenious manner. So, as far as the source of generation of this metal is concerned that is I hope you are aware of mostly it comes out of the industries or the municipalities. So, the material depends upon from where it is getting generated its toxicity will depend upon that normally it is understood that the industrial waste are going to be more toxic as compared to the municipal waste alright because of the level of activities which are quite different another interesting aspect is the waste may degrade in harmless products or sometimes this may also be a harmful product also. Waste could be hazardous and non-degradable and sometimes the hazardous waste depending upon their cumulative effect or cumulative different detrimental effects they might become very critical to handle. So, these are the four forms of the waste which normally we tend to deal with solids for example would be you know any industrial process you take the solids that generated mind tailings particularly different types of fly ashes which come out of the system slag which come out of system red mud which come out of system alright. There could be the soil which is disintegrated completely and you are trying to create an infrastructure and somebody has recommended that remove the soil and fill it up with the right material, granular material. Now the question is where to dump this type of soil. So these are the solid form of the waste similarly dredged material could also fall in the category of the solids whatever you are taking from the water bodies be it sea, oceans, lakes whatever you are dredging and you are keeping aside this could be in the solid phase liquids are also associated with industrial process domestic process sea waste sludge could be of any type it could be industrial or it could be domestic. Any type of sludges and sludges normally contain gaseous phase and liquid phase and solid phase alright. So, these are the four situations which normally we have to deal with and so solids, liquids, sludges and gases and then there could be a combination of all this depending upon the multi-phase system which we might be interested in dealing with as I said it would depend upon the source and sometimes the waste may get disintegrated or degraded into harmless products. This concept is now being researched by Arif my student. So we are more interested into degradability of the materials, geomaterials and I have been emphasizing since first lecture that you know the practical situation is where the material does not remain as it is always. So modeling becomes very difficult that means the properties of the geomaterials including the waste materials they keep on changing with respect to time. So this is the new dimension which now everybody is trying to work on they are trying to see how degradability of the geomaterials be soils, be it rocks, be it industrial bi-products, waste products and so on is taking place number one and how to model it mathematically so that it can be employed in day to day life. Sometimes waste could be non-degradable also. Now the question is which one is better degradable material or non-degradable material? What will be your answer? So this question itself is a philosophical question it might be having different types of answer depending upon the type of material you are working with. So sometimes we want waste to this degrade like municipal solid waste there is a whole idea of putting into landfills so that it gets disintegrated degraded and then after 10 years when I come over there it is all in the passive form very nice but you might not be able to convert all the waste into this type of passivated form because they are non-degradable and then the problem lives along with the material for several years. I hope you are getting a feel of this. Sometimes the materials could be hazardous sometimes the materials could be toxic so these are the attributes associated with the material which we will be talking about in details. So it is very interesting to understand what are the definitions which people have given for defining the waste as such. So there are several definitions and interpretations and why I am citing it here is that it gives you an idea about that how abstract and incomplete the definition of the waste are and hence many of you question that you know what are the research components associated with the subject. So when you start reading these definitions and interpretations lot of ideas come to your mind and those ideas become a very very glaring example of contemporary research. So if you read the first definition which is given by United Nations environment program this being a UN body their emphasis or their focus is entirely on a different aspect of the waste. So if you read the first sentence that self says waste other than radioactive waste. I hope you are getting a feel of you know why the directly they talk about radioactive waste only why any reason for this. Sir let us say always waste are not reactive so radioactive it starts up like for very reactive words. Why UNEP should be talking about all the waste put together in one class and radioactive waste put in another class that is the question all that is fine first try to understand the language. Why UN is more interested in all the categories of waste on one side and radioactive waste on the one side obvious reasons try to understand. Anyway so waste other than the radioactive waste which by reasons of their chemical reactivity or toxic explosive corrosive or other characteristics cause danger or likely to cause danger to the health or the environment whether alone or coming into contact with other ways are legally defined hazardous in the state in which they are generated or in which they are disposed of or through which they are transported. So a lot of things have been talked about the materials alright transportation disposal utilization reutilization combination of different ways interacting with each other any chemical reaction which might occur in the system alright in isolation and in combination. So I hope you realize that see this is how you read the text and then you form research ideas are you getting this idea or no that is the genesis of the research. So when you think about all these issues then the research develops so if you read these words they connote to some phenomena a process is this okay I think I am trying to tell you how to imagine something which you should be working on in the days to come. So this is how newspaper headlines might you know bother you and you might start working on those topics. So materials which are inherently dangerous to the human body or to animals including but not limited to materials that are toxic and poisonous these are the attributes of the ways which have been talked about you know they are irritants. I might see you and I might get irritated so for me a person whom I do not like might be an irritant you agree that could be a situation. So it is an attribute it these type of materials are strong sensitizers their strong sensitizers means what is sensitization so it is one of the sensitizing agents so if you are traveling in locals and maybe congested malls what you feel you get sensitized the smell of the sulphur which bothers you suppose a person like me walks through a fish market I know many of you would not get sensitized but a person like me will get sensitized because I normally I am a vegetarian but those who are not for them there is no sensitivity but those who are they get sensitized just by seeing just by feeling or just by smelling and so on this could be flammable also I think we have talked about these issues in the previous discussions that many times it happens that the waste in the landfill under certain conditions of chemical activity or environmental temperature and pressure might become flammable a good example would be different type of oils or the hydrocarbons which are lying in the landfills and when peak summer comes you know there is something known as their flashpoint index or there is something known as vapor pressure they may catch fire and once these materials catch fire in the landfill the landfill system is going to become unstable then we could have explosions also because of fire or vice versa there could be a fire and there could be explosion or there could be explosion there could be fire so I am sure when you were a kid maybe 10 15 years back when the Iraq war took place and lot of Indian companies they brought this crab from Iraq to India particularly the steel scrap so the chances were that when they brought it and they were smelting this material there were unexploded bombs also in the scrap and when they put it in the furnace their whole industry got blasted particularly this happened in Delhi a lot you must have read about this no so I mean this is something we directly influences the society alright this is the waste material from another country which I thought that I will carry along with me to my country and I can flourish and ultimately what happens there were some unexploded shells life shells and the moment you put them in the furnace they exploded alright they could be infectious so many times the attribute of the waste is that they are infectious either by themselves or when this material comes in contact with some other material so this is a potential source of transmission of disease to humans domestic animals or wildlife alright so these are the attributes which normally we talk about this could be radioactive also the waste could be radioactive material which I have been discussing so sufficient radioactivity and it so happens that nowadays because India is becoming a atomic major we have to establish several atomic waste disposal sites so that our atomic program goes uninterrupted and this is a lot of association of geotechnical engineers has to be and I think I have discussed about these issues in earlier classes where the question was how to isolate the radioactive waste from the geoenvironment how to dispose it after disposal how to monitor what is happening in the geoenvironment and so on. So these are beautiful examples of why environmental geotechnologist should be very active in today's world pesticides so the more and more agriculture you are trying to have in the country the more and more issues we have discussed about this so more and more fertilizers more and more pesticides and ultimately either this goes to the plants which is known as plants uptake capacity or sometimes the soil itself might get deteriorated because of application of pesticides and fertilizers particularly chemicals and hence people are nowadays talking about the organic fertilizers. So I am sure you can imagine now different types of situations which might occur in the society a farmer would be having a different type of issue associated with farming and hence production of the waste products as compared to the guy who is coming from industry and he or she is facing another type of problem but the magnitude and the type of the problem remains same.