 I am Munish Chandel, I am back and you know on Saturday we start talking about the waste management which largely means solid waste management, I introduced to what will be taught in this course and today I will have two more lectures and we will discuss further about the solid waste management. As I mentioned we are largely talking about municipal solid waste management which is a prime concern you know because many of your queries says that you know we should cover this that and many other topics which are really interesting for example hazardous waste, industrial waste and many more. You see if you see this environmental studies or environmental science and engineering course it is very difficult to teach this course. And I say it is very difficult to teach this course why because you know it is so broad and wide and there are so many issues and questions which need to be answered by all of us and most of them I would say in all are relevant all are important. So the question comes for this course is that how and how much I can teach in this particular course rather than going away from you know to very important questions for example deforestation what happens in this city what happens that for example someone even asked rightly so what corruption. So you know what we have to try on which I have also tried and you should also try when teaching that do not allow this course to go far away from what you want to teach. So that means you have to fix your curriculum telling and believing that this is what I have to complete this is what I have to teach otherwise all issues are important and everything is interesting so you will otherwise end up having a course or taking your discussion in direction which has probably then most of their contents are not covered. So that kind of thing need to be considered please consider that when you are teaching it and we also try to do that so that means we have to find that what is important how I can what can be taught in let us say 40 hours of lecturing and then a few hours of tutorials you know and also when he says that we can give assignments to students true we can give assignments to students that is true but for example if a student is doing 6 courses then if you believe that he can be asked to read for let us say 16 hours or 14 hours that means he just have 6 hours of assignment time for all 6 courses that means 1 hour per day kind of thing you can give assignments but if they are infinite assignments and too long probably you should not expect results because if you give something which is infinite he knows that I cannot do it so I will not do it. So coming to then what we teach here at IIT Bombay is the after talking about transportation we talk about transformation so what is transformation transformation for many of us is actually in another lines in other words you can call it is a treatment of waste and that is the component which is missing largely in India because we collect waste probably not using the most optimized most critical path but still be collected because this is a responsibility and this need to be done otherwise the communities of people living in municipality will be in trouble but after that the transformation which actually means treatment is missing and that is what we will talk today and that is what is we will talk about what is relevant in India and how many other countries are doing it. So why should we transform or treat our waste in fact if we treat our waste it will lead to efficient storage handling and transport it reduce the disposal cost that how much ultimately we have to spend on the final disposal it will stabilize our waste and destroy the toxic elements such as chemicals and biological entity and in many cases we can generate some useful energy which we will talk also and then we can reuse part of our waste. So that is why we should think of transforming our waste so that least amount of waste is going to the final disposal and we are using it one way or another. So there are different methods as everyone of us knows there are physical methods there are chemical methods and also the biological methods. So for example when I say that physical treatment basically it means a few things that I separate different components I reduce volume or even I reduce size so how can I separate different components I can do it manually for example I can have a conveyor belt on the waste is moving and I have several people who are separating for example paper plastic wood stone and maybe some kind of electronic waste which probably can be hazard etc. And we can do it by different mechanical methods which we will talk little bit later and then another way is volume reduction for example compaction compaction is good way of reducing the volume otherwise if you are not reducing volume at different levels it will lead to different lot of cost in the transportation for example. And then the third one is the size reduction for example if I want to do further treatment what I sometime have to do is reduce the size of the material so that you know my different machineries can work on that. So that is what the physical transformation the second component of the treatment is the chemical transformation for example the one which is significantly important for our waste is the combustion and you must have heard that we generally call it incineration for solid waste. So what is incineration combustion everyone of you or your students may be knowing it it is basically thermal oxidation that means at elevated temperature we oxidize our waste to final products such as carbon dioxide, sulphur dioxide and other oxidation products and of course we get a small amount or depending on the waste amount of good amount of ash may be so what is the advantage of combustion or incineration every one of those that it reduces the mass and volume considerably however it can also produce air pollutants which we will talk little bit later. And the second chemical transformation could be pyrolysis in pyrolysis we do not pass oxygen it is a destructive thermal destruction at elevated temperature but in the absence of additional air or oxygen and what we get is tar oil, we get pyrolytic oil and sometimes some gases which can further used and then of course we get char also. Then the third one is the gasification it is a partial oxidation somewhere in between combustion and pyrolysis we use some amount of air or some amount of oxygen so that our solid waste is converted into a synthetic gas which largely contains carbon monoxide and hydrogen and that actually is that carbon monoxide and hydrogen is a fuel is a low calorific fuel that can be further used for different purposes even for example running gas turbine or even for some kind of processes etc. There are different ways this chemical transformation method the incineration is the one which we will talk and which is used but pyrolysis and gasification are also options there are these things are tried in a very small scale and I would say that not much that much commercialized especially for solid waste. Then the most important one if you remember I told you that up to 40 to 50 percent of our MSW basically is biodegradable so that means the biological treatment options certainly has to play a big role so what we can do with our waste largely we can compost it or we can do anaerobic digestion when we talk about compost is basically a conversion into it is a biological conversion in the presence of air or in the presence of aerobes that means we are using largely aerobic bacteria. So what do we produce is the compost it is basically a humus material which actually you may be knowing that you know composting is the most common thing which people think or people know about the solid waste and in fact one of our participant even told that she has composting happening in her house also so that is one method which probably can be used and the second one is the anaerobic digestion it could be at low density for example what I do is I mix some of my MSW biodegradable composition with water mix it properly and make it a slurry or I can have a high concentration solid but the concentration the amount of water I add is little bit less. So that process is called anaerobic digestion in fact if you understand it that basically what we call as biogas generation we generate biogas which has methane and carbon dioxide also but this methane actually is a fuel and in many places we can use this for the generation of electricity with the generation of energy for example we can burn it especially if you are for example if you have institutions like IITs or other institution we can produce this biogas and use in hostels etc. So these two methods of biological transformation are I would say commonly used in the 12 countries and now increasing in India also and very important for us for the reason because most of our waste or let us say half of our waste is actually biodegradable and those technology will be relevant. So when we start when we talk about what method to use actually these physical chemical and biological methods especially physical and biological methods are used together for example you must have understood that for example if I want to put my waste in a anaerobic diaster or sometime in composting unit so I have to shred it I have to make it into pieces or for example if I have to use plastic etc. further even for pyrolysis etc. So I have to shred it so we can use different kind of shredders you understand shredder we use shredders nowadays in our houses in the kitchens to shred the vegetables etc. So that kind of the principle is same it is basically shear shredders so we can use it and in fact they are used in many of our processes. And then other physical method of for example commonly used in MSW management is trauma screen you may have a step seen if you see in this picture I do not know how good the quality is but if you see there are series of trauma screens here. So what happens here is basically it is a rotating screen which has slots on that so that means you put your waste from one side for example in the first trauma screen it rotates and it move your material so the material which is finer than the slot it will come out and the remaining will go to the next trauma screen which has a little bit coarser slots and then it goes to the little bit more coarser. So this is one way of separating the material the solid waste based on the size okay so you can first for example shred it and then put in the trauma screen or you will straight way put your waste into a into the series of trauma screen depending on what you want to do after okay and then there are you see as I mentioned that in our MSW there are different components I would say that if you want to classify there may be let us say 20 odd components so to separate them physically or even to deal with them separately you need a combination of technologies it may be that you need a shredder you need a trauma screen or you may also need air classifier. So air classifier is nothing but a system which is to help to separate different materials of your MSW based upon their density okay if they are very they are less dense they can flow with your air and for example can be separated from the heavy materials for example if you see the simple schematic here this is your MSW feed in a system which is which has air flow vertical air flow and once you mix this waste with air so the lighter fraction of course will be transported along with air here and the heavy fraction because of their heavy because of high mass because of the gravity force they will fall here and once they go away you have can have a further blower etcetera if it is required and then go to a cyclone separator. So what is a cyclone separator basically it separates your gas and solid. So all these solids because once we have increased the area here they will fall here and the exhaust air will take away will go away and then probably it may not be good idea just to allow this air to go to that atmosphere so what you have to do is put it back probably otherwise it will it will be may as many times you be contaminated air. So you can use air classifier also for example if you want to remove let us say paper air classifier will work nicely ok. So what I am trying to say is there are different methodologies which are to be used either in combination or individually depending on what you want to do with your waste ok. Then another one you may be knowing that a I think less than 1 percent or depending upon where but a good amount of your material can be ferromagnetic in nature that means it has magnetic characteristics that means we can use magnetic separators. So what is a magnetic separator what we do is you put your waste on a conveyor belt and you transport it here and then you have another conveyor belt but which has magnet on which has a magnet onto that and what happens when you waste goes here because this magnetic field here this your waste is picked up and your magnetic material is picked up and when it reach towards the end of the conveyor belt this magnetic field is released so all your magnetic material will fall here the remaining portion will follow. So this is a one way of separating your ferromagnetic materials from the nonferrous or nonferromagnetic materials. So it is interesting idea and what will happen sometimes it will also pick some of impurities because many times it is the many impurities are embedded in with each other so you will find that there are some nonferrous material also coming here. So what you can do is this you can have these system in series ok so that means in the later stages probably it will be further refined ok so this is used for the separation of magnetic material. So all this in fact if you see any of your environmental studies or solid waste management there are numerous other technologies also I just wanted to give you an example that how these technologies are used and how they many of them work. So the most important technology as I mentioned is biological processes and out of that the composting is the most simplest one you know it is a kind of many times I call it a free process where you have to do nothing but just have a should have a system where biologically aerobically your waste will be composted ok. So composting has several advantages you may be knowing it that it transports biodegrader compound into biological stable matter and it reduces the volume many times reduces the mass also it destroys the pathogen insect this is very important because otherwise what will happen is there is this waste in itself if we do not do the composting etcetera and put it in for agriculture use or put it into our crops etcetera that will carry pathogens that may be dangerous so that means basically this composting can reduce pathogens and whatever we get after composting is a humus like material which actually can be which is rich in nutrients and which can be act as a stabilizer or soil conditioner actually ok. So along with your fertilizer you can use this in your agriculture farm you may be knowing that the composting is a thing which is tried in many parts of our country and in fact we are doing it even now there are some issues with that especially when we are doing it large scales where are the markets ok. For example if you see our waste is generated in the cities and largely the agriculture areas are should be away from the city. So probably the question comes that where is the market for that and what were the transportation cost the biggest challenge what has happened with the composting in India is its content if we do not segregate waste properly for example we do not have system for dry and wet waste if we mix for example glass inert materials plastic etcetera with this material and then make a compost and then sell it to farmers probably there will be there will be this compost will destroy their farms and you know there will be for example if it is a glass is there then there will be problem with that. So in the large scale there have been some issues dealing with the composting but nevertheless composting could be a good choice there are different ways of doing the composting one is the conventional way of the pile our waste we have long long piles of our waste which is called windrow composting sometime we have now rotary drums basically they are drums half filled up with the waste and then rotate maybe once in hour or once in a minute actually in very low speed and little bit more controlled system and nowadays or actually not nowadays but for many years now we are also looking into vermin composting especially if you have a land is available please remember that this composting actually need lot of area and lot of land. So if you are dealing with this waste in a very in a city where the land is very precious and not available then we have to see how to use these technologies. So I will show you how the windrow composting will look like yeah so if you can see here these are basically these are the basically windrows where you have piled your waste and you see through this aerobic this composting is generally aerobic process what you have to do is you have to make sure that there is a certain amount of air available for bacteria to survive but also you have to maintain the temperature otherwise what will happen if you do not pile it if you do not maintain the temperature the process is really slow that process will become really slow for example you may be knowing that initially this bi-biological process the temperature will really go up let us say 45 degree even as high as 45 degree centigrade so these temperatures for at least for initial few weeks need to be maintained. If you do not maintain it what will happen is that the biological process will slow down and it will take longer much longer time so what you do is you pile it here maybe after 7 or 8 days you put it you move it till to the next level and then after 7 days to next level and let us say in 2 months or so here where it is maturing for a few 1 or 2 weeks further and this composting should be ready for the for the commercial use then you can send it to maybe the commercial vendors or the farmers. Please remember that once we produce compost we need to separate some of the components for example what generally the people has done is once it is produced compost is produced you again do the use trommel screen etcetera so that you can segregate the material which otherwise is not required farmers by the farmers. So this is the simplest one called Bindrow composting very relevant for country like India especially for the small for the small size cities where the land is not that big problem however you have be able to see whether this can be even used for the larger cities. So this is one picture show here taken in the Mumbai itself from where they are doing the Bindrow composting basically it is a semi-interested waste ok so for example you will still see that there is good amount of plastic etcetera here so basically if before it goes to farmers it need to be separated and actually in this side particular side they do it they separate these materials by using trommel screens ok this is the final product produced you can see the color it is very fine in fact everything including all this plastic and all these materials which otherwise should not go to the go to the field is removed here. So this is this is the final product and ready for putting into the farms ok the another one for example what has happened is that if you want to do this composting Bindrow composting especially in the open age etcetera sometime if it is very close to the communities there is some issues of orders etcetera you know it is although it is a biologic process but still sometime there were there are issues of the order etcetera. So you can do it this composting in more control fashion which is called rotary drum composting especially for example even in institutions like yours probably you can instead of having open Bindrow composting probably rotary drum composting could be a good idea. So what is so this is this is a typical view of a rotary drum in fact it is a big drum depending upon what is the requirement largely maybe half field or so that there is enough space for air movement etcetera you fill it from one side and it is some many times it is on slope so it slowly slowly moves and let us say in two or two weeks or even three weeks this can come out of it. So what is the advantage here you can regulate your airflow if you want you can easily maintain the temperature etcetera. So basically it is a controlled system rather than doing it in open you can control it further and if for example if order is produced you know that order is a big issue for solid waste management you know many of our plants in fact their success will depend whether they produce an order or no for example I was talking to someone from a municipality they are saying that the biggest problem we are facing in terms of dealing with the people is order for example if your site is having order people bond accept your technology irrespective of how good the technology is. So in fact in this system you have a system in which you can extract the gas which is produced and you know pass through even a bio filter so that the order is not there otherwise sometime it is not always but in windrow composting etcetera there is sometime the problem of order is there. So this is a more controlled way of doing it and I would say a better way for institutions or for the small scale. For example IIT Roorkee has mastered some of this systems for rotary drum composting and many others are also working on that. Then the third one which many of you are familiar with or especially in the rural settings the people use earth bombs instead of using bacterials they use earth bombs for composting of organic matter. These are these bombs are and you know this rainy season is coming you will find that there are bombs everywhere especially in IIT bomb where we find in the campus if in the big after a big rain there are number of bombs the which are just lying or moving on the road. But and they are very interesting for example 1 kg of bombs can consume 1 kg of residue every day that is good amount but it is not that all the bombs which we get in our locality etcetera they will do the vermicomposting. Of course they can do vermicomposting but the rate is very low and you do not get these results of 1 kg for you know in a day of food. So we have in fact imported one imported bombs for example this uterlis eugenia and isenia fettida they basically are the I think one is of a frequent origin and another mother is I do not know Europe or somewhere else. So they actually are much faster and you know they cost a lot for example someone told me it cost nearly 1,000 for 1 kg but then you do not have to buy many of them you know they produce so fast and in fact many of someone was telling me that even this is a business for many of because you produce those bombs and then sell it for that vermicomposting. So this is another way especially in the in the small scale this can be used I do not know many plants which are used in the large scale but vermicomposting is one of option and the residue for example the excreta coming from this bomb is also rich in nutrient and very stable materials so that again can be put in agriculture farms etcetera. So the one important technology which is emerging in many ways or especially in if you see in Europe etcetera they are when people are thinking of you know one way is to deal with waste is think it is a waste and so another way is that in fact there are so many materials in the waste which can be used either one in one form another and with this perspective many of people are thinking that okay composting is a good idea but if what if we can even generate some useful energy because energy is a new concern along with other things so for that matter the anaerobic digestion of solid waste especially the biodegradable waste is a idea which many of European countries are exploring and in fact using it. So what do we do is instead of having the aerobic conditions we have anaerobic conditions we have anaerobic bacterias we take food largely or maybe sometime even the sewage sludge can be used and put into a digestion tank there are different ways of doing it there are batch system there are continuous system and convert it into in a reasonable time let us say 3 weeks or 4 weeks into biogas which is largely methane and some amount of CO2 and H2S etcetera. This can be done in many settings especially it should be good in the small scales there are there have been it has been tried in India from the larger scale for example Lucknow is one example where they tried in larger scale there had been some issues if dealing with it in a larger scale because if our waste is not segregated remember that any of biological processes want work so nicely okay it is something like someone is given a food but a good amount of food is either of no use and maybe even injurious or even maybe toxic. So that is exactly what has happened with this system because in our commingled waste we generally have batteries we have stones we have all kind of mixed materials we try to segregate them then segregate is not 100% efficient and then in our digestion tanks we end up having a mixture of waste which is not necessarily biodegradable but also other material. So that kind of challenge is happened but nevertheless if we have dry and wet waste segregated this technology can work nicely and you can generate useful energy. This is a nice schematic of a system which is a dwelt by Dr. Kale from Bark Baba Atomic Research Center he actually has pioneered this technology for many years now if you see he has I think more than 200 plants in India which are many of them working nicely. So what is this is this is a big tank an orbitization tank and this is a methane or biogas holder. So the biogas is generated here and this is this holder it is a movable holder it collects all our gas all the gas here and then it can be used for example either in your canteen or if in the hostel etc. For example in the Bark campus they are using it for in the canteen for the preparation of food etc. So whatever residue is coming out they have called manure pits basically they are the sand beds where they are removing the solid materials from the and removing water and okay we are putting it back so that you know it does not lead to the water pollution and if you can see here there is also a heating system. So what they are using they are so using solar heater so that if your part of your reactor is heated in fact is a two stage reactor where this one first stage is thermophilic aerobic in nature and the second stage is anaerobic in nature okay there are different types of them used or dwelt commercially many even in India okay as I mentioned if your waste is segregated it is biodegradable waste then certainly this technology will work nicely if your waste is mixed then there are different issues different challenges toxicity issues for the bacteria is there okay so but in small scale certainly these systems can work. So you know the interesting question comes and many of you may be thinking on the same line is that we can generate energy and of course we can generate energy for example I already told about anaerobic digestion but the question is that how much is that energy will it offset the total cost of our these kind of systems or not okay. So there are and how much biogas can we generate there are simple base of doing its say of approximating how much biogas we can regenerate it all standard books has that but I generally do not teach that part in my class because that certainly will take half of the lecture which is little bit longer for this course but there are some studies done for example this one company West and Pax have done a study what they did is that they take 150 tons per day of MSW and they calculate that it can produce 14,000 meter cube of biogas with a methane content of as high as 55 to 65 percent and which can be used to produce 1.2 megawatt of power that is very interesting that means if I have approximately let us say 150 tons per day of waste coming I can produce 1.2 megawatt of power. So that is very good idea for example if I assume that the Mumbai's MSW is approximately 7000 tons per day it will produce 56 megawatt of electricity for me okay and that is that is a decent amount but then if you compare how much electricity we are using in the whole Mumbai so that means this is even less than 1 percent of the total Mumbai's electricity consumption and is it how much in terms of money. So what I request is and I have requested I generally request this in my class also that if I assume that I am generating 50 megawatt of electricity from 7000 tons of per day then how much revenue can be generated from this on the annual basis and if I assume that I need approximately let us say 4 to 5 rupees per kg for my based system for my based management system how much of that can be even offset by using electricity generated of that. So please do that calculation so that I can also talk to many of you it has been calculate assuming the same system which is shown in the slides assuming it be to Mumbai for everyone and calculate how much electricity we can generate annually and what will be the revenue that we will generate and how much is that in compared to the money we have to spend on the dealing with the waste if I assume let us say 5 rupees per kg for the total waste management. So I give you let us say 3 to 4 minutes for this calculation you can talk to your colleagues your friends and maybe do it together and but I would be happy if you can tell me that how much of this will offset for example this is equal to 10 percent of the total cost it can offset or 50 percent or so. So I give 3 to 4 minutes and maybe then I will come up to few centers hello Mahatma Gandhi Noida so have you calculated for example if I ask you that how much revenue it can be generate. If we consider that total generation of solid weight is 1500 ton per day then the total of 14 into 10 to the power meter cube biogas generated so about 12 megawatt power is generated electricity is generated why the solid waste per day. 12 megawatt okay any other question you have from Mahatma Gandhi. So my question is that what we what I know is that transformation of waste is that you are changing the you are changing the waste mechanically or in any other way but without recovery of any energy but in your slide you have shown that even the recovery of energy comes under transformation so is it right. Yeah I think so anything. Government of India manual if you see that transformation they say is anything you do just to make it more compact or shredding or anything but without recovery of energy. Yeah very good so I think for me the transformation is anything we transform whether it produces energy it produces useful material does not matter okay so if it is written in that way in manual probably we have to rethink on what is written in the manual okay does not matter whether we produce energy or not produce transformation is transforming it to some other form if it produces products useful products good anyone else. Thank you sir I think no more questions from this side. Okay sure okay kathal at CTM good afternoon sir how are you yeah so can you just find sir do this that calculation which I mentioned could you do that. The calculation is going on sir but there is a query regarding vermicomposting sir yeah you have told us two species Virginia and Isinia fitrita sir yeah so this is a dry area in which approximately 400 to 500 annum rainfall is receiving this area per annum sir yeah which species is suitable for vermicomposting in this particular arid area sir. Very good question okay so what we have to do is you have to call to G.G. Hissar you know G.G. Hissar I know yeah so and call to Dr. Gurg Dr. V.K. Gurg is there and he is an expert on vermicomposting so he will tell you which one you should use in the arid areas okay yeah yeah any other question yeah so please try to do that calculation and you know why I am giving you this calculation is to give an idea to give an insight to understand that how much of our cost of our treatment our whole solid waste management can be dealt when we are talking about generation of some energy okay that is the reason why this numerical small simple numerical is given. Thank you very much Shri Vaishnav Institute Madhya Pradesh so could you do that calculation. In Indore we are having a severe treatment plan third and they are generating 22 kilowatts power daily and with the capacity of 122 MLT they are having that severe treatment plan and they are generating the electricity in the municipal corporation they just started the severe treatment plan they are generating the electricity power. So it is a biogas plant. Yes sir. Very good so what is the question. My question is there are two methods of biological transformation of solid waste one is aerobic method another one is anaerobic method. Yeah. In anaerobic method of digestion we are giving we are getting the biogas also that is the advantage. Yes. So here these two methods so this method is more economical more efficient and more successful. Okay very good question. Yeah okay very good question. So I think the question those who could not hear is that there are biological there are two ways of biological methods aerobic and anaerobic. Anaerobic is also produces energy that means biogas which one is good. So you see it is very difficult to tell depending on situation you have to use it but the aerobic processes generally are economically cheaper the cost is on the lower side okay but on the other hand the anaerobic system can produce you energy so you have to offset base to have to do the cost to benefit analysis but if you ask me that I do not want to invest I just want something which works for me I will start with aerobic processes but if I am able to invest money and you know want to even produce energy then I will go with anaerobic processes okay. There are certain advantages and disadvantages of both the processes so you have to see that which one is good for us for example once you have done anaerobic process then again that residues which is coming sometime we have to do again the anaerobic composting of that. So anaerobic little bit will be on expensive side but then there is the energy generated out of it and of course but the investment is on the higher side. Very good question so what I request you all is just do that calculation and if someone has done this calculation please tell me that how much this energy can offset the total cost. So very interesting questions you know many of you are of course teaching this course probably even longer than what I am teaching here so it would be interesting it would be nice if you have some interesting way of teaching some of these materials. If you can share your ideas so that it should not be a one bit traffic ultimately the whole goal of this workshop is to discuss and to understand how this course can be delivered to the students most effectively. So if you are using some good methods and if you think they are working nicely please share with us please share on the model etc okay so that will help in developing this course for the benefit of all the students. So you know I talked about biological processes very interesting processes there are different challenges in fact there is no full proof technology for anything there will be issues which need to be dealt locally for all kind of technologies be it biological, non biological, physical etc etc and then the another route which many of us will be thinking or especially on books is the waste energy I mean waste energy is any system in which we can generate energy but this incineration largely is called system in which we call them waste energy. So basically it is a thermal route instead of going the biological processes or we can go the thermal route which is called incineration which is called waste energy. You know this is again a very simple okay not so simple but very interesting process what you do is you take your waste pass into a combustion chamber pass air so that there is sufficient air for the combustion the heat will be generated you can extract that heat generate run a steam boiler and produce steam and then steam can produce electricity etc or in some cases you can just simply burn it because what is whether we can generate energy or not generate energy will depend on the calorific value of our waste okay and the incinerator shouldn't be considered just like a simple burning system but we should have all air pollution control devices we have regulations for that we should at least have a at least let us say wet scrubber and then let us say filter fabric filter for particular matter control etc. So this is here this flue gas is going out we have couple of then there is a wet scrubber and then there is a filter and then this flue gases are going to stack and after this this burning here this ash is going to the ash collection system and collected then cooled and then maybe disposed of okay so this thermal route is another bay in many places it is seen in different ways for example we are now trying to go in thermal routes especially in Delhi if you see there are couple of plants now in operation there are concerned about the air pollution and they are also concerned that what is the calorific value of our waste for example you know if our collection systems are open system for example we are allowing to air to water etc to especially rainy season to pour in. So what will be the calorific value of waste and if I am saying 30-40% of inert materials which probably has no calorific value then the viability of this system need to be explored but in addition to the calorific things calorific value things you may be knowing that many countries even many developing countries do not want to use incinerators and for that matter okay this based energy systems are the same. So why because there is a concern about the air pollution it is many of these countries also are seeing it something like this that you have problem which is called solid waste and then you are burning it and then creating air pollution that is then the problem of air. So you know it is not at all a good idea to convert your one for our problem to another problem if you see there are several numerous air pollutants which will come out of incineration for example organic compounds dioxin and furon if you read nowadays any newspaper and every now and then they will say that x, y, g burning has lead to of waste has lead to dioxin formation and furon formation there are poly chlorinated biofinals there are VOCs there are polycyclic aromatic hydrocarbons and there are benzenes chlorinated benzenes there are heavy metals produced actually arsenic, cadmium, chromium, copper, mercury, manganese, nickel, lead of course it depends what is in your waste and then this particulate matter in overall 2.5 pm 10 inorganic gases HClHF, HBr, SOX NOx and then of course we get gases like CO and CO2. Okay so these all many of these pollutants are really dangerous to human and this has been a concern that is why many of countries have thought that okay waste energy or incineration is not a good idea of course this fly ash for example we generate from our incineration can contain many of these PCBs, polycyclic aromatic hydrocarbons, dioxin, furons and heavy metals etc and of course this wastewater for example from this wet scrubbers if I am generating this wastewater which actually can be a really toxic in nature these concern has led to think of incinerator in many different ways okay many think that it is not at all a good idea. The biggest concern for this incinerator has been our biggest concern which is more publicized is dioxin and furon if many of you who have must have read the book of Rachel Carlson, The Silent Spring she was the first lady who you know brought these issues to the in the public domain and then you know in fact good did a wonderful job into telling that okay there are the concern about dioxin and furons and other also she has mentioned in her book but what are dioxin and furons so you may be knowing that these are this chemical structures of the dioxin which are polychlorinated dye banjo para dioxins and there are four to I think at least four chlorine atom onto this and this one is low polychlorinated dye banjo furon. So there are approximately 75 dioxins in the environment or may have not in the environment but has been invented and seven of them are really toxic to human and similarly there are furons at least out of 135 available there only 10 of them are toxic. So this dioxin and furon has led to a especially in addition to other prudent has led to concern that you know we do not want to incineration so what happens how this dioxin and furon are formed once we have hydrocarbons once we have a chlorine available this at elevated temperature this these compounds can form dioxin and furon and you may be knowing that many of many of them are really toxic 7 plus 10 and they have been found at least to lead to a cancer or all kind of or kind of disorder in human. So that has been you know led to a concern that is why many people think that no incineration but let me tell you also that you know this dioxin and furon forms in the incinerators but they also form they also are formed in when we are doing open burning for example if we just burn based in open and if it has a chlorinated plastic or some other source of chlorine and then some of course there will be hydrocarbons it certainly would produce dioxin and furons. So in incinerator in fact we can control them we can regulate them and we have some technologies available but in open burning probably it will be more dangerous okay so that need to be seen and in fact we do not have very good data to tell that how much dioxin and furon are already in the environment there are just couple of studies one is done in Japan for India which tells that in some of our food products I think not exactly food products but in some places they have found that dioxin and furons okay. So do we have control technologies for them of course we have control technologies for dioxin and furons for example they can be adsorbed on activated carbon beds and they can also be controlled by regulating the temperature okay. So another technology similar to incineration is the gasification I already mentioned about that but it is a little bit of advanced technology I would say in fact we do not do the complete combustion but we have partial oxidation we produce carbon monoxide and hydrogen and then use it for running even gas turbine or you using this as a fuel. I would say the gasification is still not that much commercialized for our gas for our MSW system there are few studies there are few trials I would not be surprised if you tell me that there are few plants abroad available but not so far tried commercially in India actually if I remember correctly okay. So these are basically couple of methods incineration gasification and you may be knowing that even pyrolysis for example similar to gasification this also tried I think in one place if I remember in Pune they are trying the pyrolysis incineration in Delhi there are two plants in a few other in other places they are trying it so incineration helps in one way for example it can reduce your mass and volume as high as let us say 85% or even more than that so that is a huge advantage but then there are other concern what do we do with the pollutants okay. So let me take a couple of more questions on gasification and etc. Silguri Institute of West Bengal yeah good afternoon sir we have calculated the earlier question yeah yeah so it is 1.6 megawatt per day in our city actually Siliguri okay and one more I have one more question actually according to the disposal actually yeah so the composting the so composting also can be done by sanitary land filling is it possible so sanitary filling is also a biological process what I would say that it is more anaerobic than aerobic should we call it a composting or not I am not sure about that because in sanitary landfill we just fill it in the landfill and keep it there forever okay so that should we call it composting probably not why do you say that that is composting. Sir my point is if you analyze some point on plasma incernation recently we heard that from plastic waste mainly municipal solid plastic waste yeah by means of plasma incernation yeah electricity could be generated in a cheaper methodology you kind of tell something yeah so this I think this institute of plasma something they are trying that and in fact I do not know whether it will be cheaper or not to be honest with you but of course they have commercialized this technology they have given license to a company like Bhagirathi something private limited or so I personally do not know whether it is economic or not but that is another technology which to me is little bit of towards advanced I would call it advanced technology you see what happens when a new technology emerges they claim I am talking in general right they claim that okay we can do this at a very low cost but when we start installing it then there are several issues comes up and once we start resolving then then the cost may be different what is what is envisioned in the beginning so it is very difficult to tell whether that plasma technology will be cheaper but certainly that technology is also there and especially for the biomedical based they are using it there are a couple of at least I know that at least there is a plant in Goa which they are pyrolyzing your this biomedical based by using this technology it won't be commercialized that is very difficult to tell now so I do have a question regarding this component separation yeah as you have mentioned that there was this separation by manual scavenging or something like that but is it possible that I guess manual scavenging the government has went against for that so how is it possible in those industries or places like that yeah so I think when you are saying that if I remember if I understand correctly so this scavenging what you are mentioning is not banned but the government has said that if someone is lifting a stool etc or fishes human fishes that cannot be done but this sorting manual sorting is a very I would say a method even used in 12 countries so it is not like you ask people to do it with their hands but you have gloves you have all your gears and then you are it's a basically the your material is moving on a conveyor belt for example I want to remove this bottle I remove that I have stone I remove that put in different containers so you know it's it's like the way you do things if you put it without any gears you are not taking care of hands you are not taking care of you there is no air mask etc of course that shouldn't be done but then it can be done in a very scientific manner and if you see any of your one video which I will also show it's done in I must almost all facilities even in the 12 countries so there is no nothing bad in that only the thing is if you start doing it by hand that certainly should not be practiced and it's then the question of the health of the people okay so thank you very much so let's say so we move further then we talked about the the disposal which is I would say the last destination when you cannot produce or cannot do the biological processes or cannot do the incineration I do not know the incineration need to be seen in perspective but whatever is remaining then if you don't find the solution that means that need to be disposed of finally and when we talk about disposal that there are many ways of disposing open dumping which is largely practiced in India for example and then many thought that you know sea is so big that if we can put some waste or if we allow the waste to go into the sea and ocean that should be also be okay but let me tell you very honestly that this is a really bad practice you are you're giving your problem to the fish that means means by that you're giving your problem to the aquatic ecosystems that's really bad and we shouldn't do that and then the third option which is scientific one is called land filling you dispose your remaining solid waste residual solid waste in the surface soils of the earth in a scientific manner that is what is called land filling and that is the which we will discuss now so why should we do landfill so it's first of all if you compare it with the open dumping it's any day it's much much better and you know even if you have for example if you do any other use any other technology some residue will always be remaining so that need to be put somewhere and that probably the landfill is a good source for that and if you're doing land filling as compared to open dumping you can understand that we are reducing public health and safety and of course the safety to the environment okay so what is landfill it's a controlled disposal of waste on the land it controls the exposure of the environment and humans to the detrimental effect of solid waste placed otherwise on the land disposal is accomplished in a way such that a contact between waste and environmentally significant reduce so this is a disposal is not a full proof for final technology but it's much better than doing nothing so for example if I put it in a very scientific manner cover it everything so that it is away from human it is away from the stray animals it's away from rodents etc and that means it cannot spread disease and we are getting away from the waste okay so sanitary landfill in that sense is a good idea and in many ways it probably will be cheaper than any other technology for example if I compared sanitary landfill from incinerator if not considering the cost of land probably sanitary landfill can be cheaper so this is a section view of a typical state of the art landfill okay so if you see here I have in the bottom of that I have a kind of liner system the idea is so that even whatever is generated here it do not allow the gases it do not allow the leachate which is so you understand what is the leachate do not allow it to percolate to the groundwater and on the top of that we have a leachate collection system so whatever groundwater or otherwise the water generated inside this landfill this water is collected there are basically different pipes perforated pipes they collect the waste and they collect this liquid and then this liquid is taken to a particular place inside the landfill only and then it is treated okay and the another important component is the gas generated so this gas eventually because if you see this is a closed system right so what will happen there will be anaerobic conditions sometime there will be in the beginning there will be aerobic conditions so there is some kind of gas will be generated which is the biogas remember that the composition of methane will bond with that high as compared to in the anaerobic digestion system but still we will have biogas generated here so if we allow this biogas to go to the atmosphere what will happen it will for example this biogas contain methane it is a greenhouse gas so that means it will lead to the global warming so we collect all of the biogas here through different gas gas extraction or gas collection wells and then probably either we flare it or then use it for generating some kind of electricity or some kind of energy on the top of these everything we put a cover which is called cap system we basically put a few layers of impervious clay and then some kind of liner and then we close the system okay because there are two kind of major pollution which can happen near nearby the landfills one is the groundwater pollution because if this leach this leach it for example what will happen if it leach is done it certainly will reach the groundwater and even those gases if they are not collected properly they will be coming out so we should have a system to my to monitor gases and we should have a system to monitor the leach so for example if you see here there is a not shown here but there is a groundwater monitoring system here and in fact it is also done in upstream so that to see that okay for example this one this is a groundwater monitoring well here and this is a groundwater monitoring downstream so that we know that once this water has gone or is passing through the the groundwater is just below the landfill whether this quality is getting affected or not so this is very critical at least you should have two groundwater monitoring wells and you know what will what many times happen is this surface water can enter into this landfill so there should be a very good drainage system in and across this landfill so that this water do not go inside so these are the few major components you know many of you know this is what I tell to student in fact in advanced classes we generally ask them to design some of the components but because in this course it is so basic so we do not ask them to design any of the component but this is the a few basic components I also tell them again that okay this is a linem system there is a cap system and then there is a gas management system then leachate management and then there are different monitoring system so this is where minimum what is what is there in our landfills so this is a typical interesting picture of showing what are the different landfill operations not many components are visible but if you see this they are spreading the waste here and in the bottom there is a liner and of course there is a soil put on the top of that then they are putting that this is probably the soil required for the soil covering so this is very interesting so when we put this when we put this waste in the landfills it is not that it is put in a single cell in fact you will see that in a landfill there are several of cells one after another so every day I feel my waste for example here I put a soil cover on the top of that and then next day I feel it here and again put a soil cover and so on so far so you will see that these kind of cells are there okay so these kind of cells will be formed and once my landfill is completed I put a good amount of final earth cover or soil cover which could be as thick as two feet and this daily earth cover could be just six inches or so so you see this soil covering is interesting but it also cost you why because first of all you have to find a proper soil which largely should be clay clay in nature and this soil will also take a good amount of your area okay because this is ultimately filling otherwise if I do not put this soil so basically I can put more waste into that so you have to optimize it you have to find the local locally available soil otherwise a good amount of your aerial the whole landfill will be will be taken up the soil but this is I would say mandatory otherwise there will be problem of order etc in the in your landfill this is one photo of showing the leachate collection well it is it is near to Mumbai this is a big well it is not so then I think it is not a continuous system but they are collecting leachate there and then maybe taking it out for the treatment so once this leachate is generated you may be knowing that you know this is this is a highly contaminated or highly toxic wastewater so this this need to be treated further otherwise what will happen that if you do not collect it will be not treated then probably it will again lead to your surface and ground water contamination so this is a picture showing of a leachate treatment system near to Mumbai this is basically sequence patch reactor if you can see the the aeration happening here and lot of the sloughing happening in the top so we need a good amount of leachate treatment systems and you you will be surprised to know that you know the many of the components in the leachate may not be easily biodegradable so sometime we have to think even over sophisticated technologies like the membrane technology and then then we are talking about all these technologies monitoring then the membranes etc that is actually leading to a very high cost of your system you know so people say that oh what is the deal be I take it put into landfill put the soil and compact it that is done that is not true actually you have to monitor the gases coming out you have to collect them you have to monitor the leachate you have to monitor the ground water and then even to treat this leachate with a very sophisticated technologies that actually will lead to a very high cost once you have filled your your solid in the landfill your job actually is not done you know in fact it should be that even after closing your landfill putting a complete liner on the top of that you should typically monitor and maintain the landfill sites to see whether there is some kind of liner hasn't broken up or whether this gas collection system are working or not even for as high as 30 to 50 years so that means in your management system you should also include the monitoring cost even for as high as for 30 to 50 years as per MSW rules in India it recommends that at least for 15 years we should monitor the sites after closing that is also a long time so that means this also will cost you a lot and after all this is done these sites basically can be used for recreational parks they can be converted even to stadiums they can be converted into gardens even some of people have argued that they can be used even for making the residential houses etc of course there will be issues of compaction there will be uneven compaction for many days but nevertheless these landfills can be used for some other purpose especially making recreational parks etc there are very few good examples in India where we have restored these landfills and converted into some kind of recreational parks etc so here is the one example which I give to my student just to estimate how much landfill is required for example it is you have to estimate it for Mumbai and for example the question is estimate the landfill area needed to handle one years MSW for Mumbai assuming national average discard no combustion and a landfill density of 600 kilogram per meter cube and a single 3 meter lift assume that the 20% of the cell volume is soil used for cover okay so please if you can solve this that we will get a chance to talk also so this will give you sense that even for dealing of one years of waste for city like Mumbai how much extra area is required and then you can assume what is the cost of the land and then you know how expensive it can be in future so you just calculate it we will give you let us say 2 minutes and then we can talk about the sanitary landfills Bengal Engineering College hello sir how are you very good sir very good afternoon yeah so hello so let me ask you a question rather than you ask me a question okay sir I am asking a question that was regarding your treatment of solid waste by vermin composting so what is the optimum condition that we should maintain if we want to compost the MSW what is the optimum condition that we should maintain okay it is very good question so you know this generally this vermin composting is done at the ambient conditions you will for example the cities or the area like West Bengal it should be wonderfully working you know it concerns sometime comes when it is very cold area the bombs may not survives that probably then you have to be put them in a area where the temperature can be maintained but it is mostly done in ambient conditions so it is a question only of maintaining food for example for them and then the moisture humidity etc you do not have to do much in fact they will survive in most of conditions like in Bengal but let me ask you a question the my question is so all four of you teach this course we are four participants here yeah but all of you are teaching this environmental studies course no at least three we are doing this okay so what do you teach in solid waste management teaching environmental studies yeah but do you teach solid waste management no I am not studying the solid waste management other teachers are there they are studying solid waste management no no so my question is that when you are teaching this environmental studies course okay so do you teach solid waste management as a part of it yeah we have the part that we have in our syllabus content that that that much we teach the youth students okay so maybe I can take opinion of the another one who is sitting left to you sir we teach solid waste management yeah so what do you teach in that is it different than what we all you have taught all we actually covered in our syllabus okay and what else we used to teach the topics like the what are the importance of solid waste management then how it is generated then what are the different character composition or characteristics we should know for the solid waste then the engineer system for solid waste management and its functional elements their interrelation then finally we give stress on disposal of solid waste management or disposal of particularly solid waste then a little bit about waste management and biomedical waste also we use to teach but that is with very small portion new waste management and biomedical waste very good and how many how many you take for this yes six hours six five to six hours depending on situations okay thank you very much thank you then so I think we have to stop here for a for a tea break and we will talk to you in 30 minutes at 3.30