1 00:00:28,260 --> 00:00:37,780 ok ah good day and welcome back to this lecture this is the fifth lecture in our series ah 2 00:00:37,780 --> 00:00:45,000 on the course of ah geo environmental engineering and the second lecture in the module on a 3 00:00:45,000 --> 00:00:51,610 ah design of waste disposal facilities or design of landfills so in the last lecture 4 00:00:51,610 --> 00:01:01,949 we looked at ah generation of ah ah ah solid waste and how we are placing it on the ground 5 00:01:01,949 --> 00:01:09,620 and ah one of the messages which you might have carried from last time was that ah we 6 00:01:09,620 --> 00:01:15,460 produce thousands of tons thousands of million tons of waste per year in a country 7 00:01:15,460 --> 00:01:23,030 so when we are talking about the ah quantity of waste typically for example if you just 8 00:01:23,030 --> 00:01:28,500 look at ash we are dealing with maybe a hundred and ah twenty million tons per year and if 9 00:01:28,500 --> 00:01:39,390 you are looking at ah mining waste we are talking about one thousand more than one thousand 10 00:01:39,390 --> 00:01:45,370 million tons per year so how do we solve this problem waste as you 11 00:01:45,370 --> 00:01:54,100 put it on land accumulates with time so i start with a small waste dump and over the 12 00:01:54,100 --> 00:02:00,220 years two things happen we will take them we spend it in over more and more land can 13 00:02:00,220 --> 00:02:08,350 we find that the more land is not available then it becomes higher and higher because 14 00:02:08,350 --> 00:02:17,180 we dont have more land so the waste dumps from higher and higher and you will often 15 00:02:17,180 --> 00:02:24,730 see waste dumps which look like huge mounds how do we tackle this problem and one question 16 00:02:24,730 --> 00:02:30,560 which i put up in the last class was can we become a zero waste society so somebody said 17 00:02:30,560 --> 00:02:37,689 yes so the title of todays ah lecture is waste minimization by integrated solid waste management 18 00:02:37,689 --> 00:02:42,650 so to to look at this problem and ah this is a huge subject integrated solid waste management 19 00:02:42,650 --> 00:02:47,819 can itself a forty two lectures on it and we dont want to get drawn into trying to become 20 00:02:47,819 --> 00:02:52,599 ah waste managers our job is to design waste disposal facilities which dont impact the 21 00:02:52,599 --> 00:02:55,849 environment around the place where these are disposed 22 00:02:55,849 --> 00:03:01,379 but nevertheless some of you said that we can become anybody who wants to say we can 23 00:03:01,379 --> 00:03:08,239 become a zero waste society or a very low waste society ok tell me two steps which you 24 00:03:08,239 --> 00:03:13,980 think ah would help us become a zero waste society 25 00:03:13,980 --> 00:03:16,689 source segregation so source segregation ah i dont know how it 26 00:03:16,689 --> 00:03:22,689 will make the waste disappear but ah source segregation is an attempt to minimize waste 27 00:03:22,689 --> 00:03:24,909 but still you segregate the waste it is still waste 28 00:03:24,909 --> 00:03:31,510 segregation ah authentics and then ah base to energy 29 00:03:31,510 --> 00:03:38,340 so if i ah segregate waste ah ah into say two components of the biodegradable and non 30 00:03:38,340 --> 00:03:43,700 biodegradables still i have two wastes then what you are saying is i can send waste for 31 00:03:43,700 --> 00:03:52,129 processing to a composting plant and to a waste to energy plant so by waste segregation 32 00:03:52,129 --> 00:03:58,049 and waste processing i can minimize waste but can i become a zero waste society because 33 00:03:58,049 --> 00:04:05,790 even when you burn everything there is ash suppose i burn everything i still have some 34 00:04:05,790 --> 00:04:13,370 ash and is the ash hazard inert non hazardous or hazardous well some ashes observed to be 35 00:04:13,370 --> 00:04:19,700 hazardous some ashes observed to be non hazardous but in the end i still have this ash and this 36 00:04:19,700 --> 00:04:25,750 has to be put somewhere on the ground so its going to consume land the only way ah we can 37 00:04:25,750 --> 00:04:30,639 say that we will become a zero waste society is if we dont have any end product to put 38 00:04:30,639 --> 00:04:33,460 in a dump so we have not reached that situation but 39 00:04:33,460 --> 00:04:38,800 we are definitely trying to reduce the quantity of waste so then what we are trying to says 40 00:04:38,800 --> 00:04:48,590 if i have a ah bathtub which is full which is like the landfill capacity is full and 41 00:04:48,590 --> 00:04:56,980 if the water is overflowing from the bathtub i am looking for a solution for this problem 42 00:04:56,980 --> 00:05:02,510 now the solution is not to do a lot of engineering here water is coming out of the bathtub all 43 00:05:02,510 --> 00:05:06,990 the time you will say all right get me a bucket get me another bucket get me another bucket 44 00:05:06,990 --> 00:05:14,200 but thats not a solution to the problem the solution to the problem is close the tap so 45 00:05:14,200 --> 00:05:19,810 waste minimization means please remember what is the ah important thing the important thing 46 00:05:19,810 --> 00:05:26,500 is to close the tap the important thing is to get as little waste out from ah your sources 47 00:05:26,500 --> 00:05:30,810 as possible and if you do that waste gets minimized 48 00:05:30,810 --> 00:05:36,850 so in in in the context of todays lecture suppose today we are producing hundred units 49 00:05:36,850 --> 00:05:42,480 of waste can we do various kinds of things and reduce it to half its value or twenty 50 00:05:42,480 --> 00:05:48,810 five percent of its value or even law so that is waste management ah integrated solid waste 51 00:05:48,810 --> 00:05:54,150 management and waste minimization our job will always be that whatever waste is coming 52 00:05:54,150 --> 00:05:58,470 out we still have to dispose it on land and you should dispose it in a manner we dont 53 00:05:58,470 --> 00:06:05,270 affect the human beings and the ecosystem around it 54 00:06:05,270 --> 00:06:14,150 so the objectives are to minimize waste and effectively manage the waste still produce 55 00:06:14,150 --> 00:06:20,400 so integrated ah solid waste management recognizes that we will not in the immediate future become 56 00:06:20,400 --> 00:06:28,650 a zero waste society but lets reduce the waste ok so what are the steps that we can take 57 00:06:28,650 --> 00:06:37,390 to reduce the waste are these one two three four five steps so first step is waste reduction 58 00:06:37,390 --> 00:06:45,670 at source please produce less waste as a householder as a human being and thats a big step forward 59 00:06:45,670 --> 00:07:01,740 ah how can we reduce waste we can reduce waste by using materials more efficiently and making 60 00:07:01,740 --> 00:07:07,650 differences in the packaging and we will come to that later because much of the waste is 61 00:07:07,650 --> 00:07:15,310 the packaging of the products after waste reduction we can try a resource 62 00:07:15,310 --> 00:07:19,610 recovery through separation and recycling so what was said was it was said we should 63 00:07:19,610 --> 00:07:27,990 do segregation we should do segregation and we should recycle what can be used so in in 64 00:07:27,990 --> 00:07:34,670 current tech context glass can be reused metals can be reused so all the stuff which the kabadi 65 00:07:34,670 --> 00:07:42,860 wala from the house takes away is the recyclable stuff the the paper is being taken away so 66 00:07:42,860 --> 00:07:47,860 we can do resource recovery through separation and recycling if we mix everything if we mix 67 00:07:47,860 --> 00:07:57,150 the paper with the food waste we lost it so keep it separate and send it for recycling 68 00:07:57,150 --> 00:08:02,960 it has its implications on the number of streams for collection that you have to set up its 69 00:08:02,960 --> 00:08:07,420 not that simple that you keep it separated its do you have separate streams to collect 70 00:08:07,420 --> 00:08:11,700 it and send it to the separate units which are going to use it 71 00:08:11,700 --> 00:08:18,370 if if you do not if you are not able to recycle something after separation can we do some 72 00:08:18,370 --> 00:08:24,990 waste processing and help further resource recovery what are the resources we are talking 73 00:08:24,990 --> 00:08:31,639 of the two resources which we are using from the environment at the moment now we are using 74 00:08:31,639 --> 00:08:38,979 energy and raw materials and we want to recover energy and raw materials and materials which 75 00:08:38,979 --> 00:08:44,250 can become raw materials for the processes because then we will need less raw materials 76 00:08:44,250 --> 00:08:51,140 and less energy so can be recovered energy through waste processing can we transform 77 00:08:51,140 --> 00:09:00,139 the waste so that it occupies lower land than ah it would have otherwise and finally we 78 00:09:00,139 --> 00:09:06,180 do waste disposal on land so these are the options that we have to look at 79 00:09:06,180 --> 00:09:11,810 so i we did this diagram earlier we are taking from the en ah environment energy and raw 80 00:09:11,810 --> 00:09:16,770 material and we are disposing the solid waste if we are producing gaseous waste and if we 81 00:09:16,770 --> 00:09:23,070 are producing liquid waste which we are what is happening the gaseous waste is being treated 82 00:09:23,070 --> 00:09:28,880 and it produces solid waste the liquid waste is being treated and it produces solid waste 83 00:09:28,880 --> 00:09:34,460 so all that is eventually permanently lying on the ground is the solid waste 84 00:09:34,460 --> 00:09:42,960 just to recall electrostatic precipitators will reduce the smoke coming out or the particles 85 00:09:42,960 --> 00:09:50,610 coming out with the gases but it will give you ash etp sludge is the output of treating 86 00:09:50,610 --> 00:09:55,490 wastewater so that the wastewater is not contaminated but the sludge will have the contaminants 87 00:09:55,490 --> 00:10:01,580 and all of them will come on land when i do integrated solid waste management 88 00:10:01,580 --> 00:10:08,010 i look at the waste which is coming out from any process and i apply these principles can 89 00:10:08,010 --> 00:10:15,440 we reduce waste can we recycle it can we process it or can we transform it so if i am able 90 00:10:15,440 --> 00:10:19,930 to take out some materials suppose i am able to take out the glasses and the metals then 91 00:10:19,930 --> 00:10:28,090 what happens the glass industry now gets an input from the recyclables so it has it uses 92 00:10:28,090 --> 00:10:33,610 less raw material suppose the waste which is coming out is paper 93 00:10:33,610 --> 00:10:41,450 and if i can burn the paper to recover energy then the energy input to the industry from 94 00:10:41,450 --> 00:10:47,361 outside sources is reduced so integrated solid waste management means you look at all the 95 00:10:47,361 --> 00:10:52,130 alternatives and see how i can reduce the energy being taken from the environment and 96 00:10:52,130 --> 00:10:58,420 reduce the raw materials then i have the products then i have the consumptive processes now 97 00:10:58,420 --> 00:11:04,460 here is where the municipal solid waste comes out and here also we can apply the same principles 98 00:11:04,460 --> 00:11:10,380 if i have municipal solid waste what can i store separately what can i recycle for the 99 00:11:10,380 --> 00:11:15,940 materials and what can i recycle for energy recovery such that less energy and less materials 100 00:11:15,940 --> 00:11:22,000 so we get less solid waste to dispose on land the size of the landfill becomes less and 101 00:11:22,000 --> 00:11:33,320 we have less energy to be taken from the environment so in terms of hierarchy the maximum money 102 00:11:33,320 --> 00:11:39,560 should be spent if we are subsidizing or if we are ah catalyzing something we are trying 103 00:11:39,560 --> 00:11:45,480 to invest as a government maximum money should be spent on waste minimization and reduction 104 00:11:45,480 --> 00:11:51,440 at source the waste is not created then our problems are lesser 105 00:11:51,440 --> 00:11:55,880 if more investments have to be made they should be made in terms of material recycling and 106 00:11:55,880 --> 00:12:03,790 waste processes material recycling is ah higher in the hierarchy because here you are able 107 00:12:03,790 --> 00:12:09,120 to get the materials without putting it energy into the process in waste processing you might 108 00:12:09,120 --> 00:12:15,620 have to put in a little energy so that you can recover the other things finally waste 109 00:12:15,620 --> 00:12:21,190 transformation and land filling so everybody agrees with this anybody has 110 00:12:21,190 --> 00:12:24,270 any ah alternate thoughts that no we could do it differently 111 00:12:24,270 --> 00:12:35,060 processing different different places like ah just slightly 112 00:12:35,060 --> 00:12:38,770 so the question is how many processing units where are they going to be located what is 113 00:12:38,770 --> 00:12:44,520 the optimal solution is that one big integrated facility or is it that small small units are 114 00:12:44,520 --> 00:12:49,990 lying everywhere let me articulate that and we are not going to look at those solutions 115 00:12:49,990 --> 00:12:56,330 yet but if i geographically or in plan if i look at a city and the question being asked 116 00:12:56,330 --> 00:13:02,170 is is there going to be one big facility with smaller facilities here recycling waste processing 117 00:13:02,170 --> 00:13:12,240 land filling or are they going to be different ah ah units spread around both both solutions 118 00:13:12,240 --> 00:13:17,550 are being used in different ah situations there is no one solution which is the ah the 119 00:13:17,550 --> 00:13:24,040 ideal solution so you may have a centralized ah tsdf as i said treatment storage and disposal 120 00:13:24,040 --> 00:13:27,480 facility or you may have individual units all around it 121 00:13:27,480 --> 00:13:32,960 so that will depend on how the plan area of a city and how large it is how larger the 122 00:13:32,960 --> 00:13:39,250 distances if this distance is five kilometers there is one solution but if this distance 123 00:13:39,250 --> 00:13:44,350 is fifty kilometers then you have another solution so those solutions will be given 124 00:13:44,350 --> 00:13:49,110 to you by integrated solid waste management where you can see how much of the transportation 125 00:13:49,110 --> 00:13:55,380 costs and how much of the processing costs normally speaking today what is evident is 126 00:13:55,380 --> 00:14:00,071 that when you deal with waste they are all we are dealing with odorous compounds it is 127 00:14:00,071 --> 00:14:05,700 better to put everything in one place because you can more intensively control ah i thinks 128 00:14:05,700 --> 00:14:11,140 that the boundaries if you spread them at too many places and each place requires a 129 00:14:11,140 --> 00:14:16,270 ah environmental control stringent environmental control but this is not the only consideration 130 00:14:16,270 --> 00:14:21,540 transportation costs and other things are major considerations ah which will ah which 131 00:14:21,540 --> 00:14:28,670 we have to take into account how do we reduce waste at source so i talked 132 00:14:28,670 --> 00:14:36,300 about proper manufacturing and packaging of products for longer useful life so let me 133 00:14:36,300 --> 00:14:43,940 say again we come back to the example of shampoo you are ah using shampoo so you buy a small 134 00:14:43,940 --> 00:14:53,589 bottle in every fifteen days you go and buy another small bottle and then at the end of 135 00:14:53,589 --> 00:15:01,240 the year you have got as your waste how many weeks in a year fifty two and we are doing 136 00:15:01,240 --> 00:15:08,520 alternate week we are buying a new small shampoo bottle so we have got twenty six small shampoo 137 00:15:08,520 --> 00:15:15,620 bottles my friend here he says i will buy my shampoo for one year in one go so he buys 138 00:15:15,620 --> 00:15:24,990 the large bottle and the the manufacturer who says i do environmentally conscious manufacturing 139 00:15:24,990 --> 00:15:30,300 says i will give you more concentrated solution so instead of putting four drops of shampoo 140 00:15:30,300 --> 00:15:39,070 you can use one drop of shampoo right so he he has a product which is manufactured and 141 00:15:39,070 --> 00:15:46,721 packaged for longer life and less waste he may not have the money to buy it because he 142 00:15:46,721 --> 00:15:51,220 is getting is in a salary every month and for him to buy everything for a year he may 143 00:15:51,220 --> 00:15:57,790 say no no i dont have the money but the point is you can with proper manufacturing 144 00:15:57,790 --> 00:16:08,360 and with ah sensible efficiencies reduce the packaging the other thing is you may ah go 145 00:16:08,360 --> 00:16:15,980 from toxic to non toxic materials or you may go from artificial to natural materials some 146 00:16:15,980 --> 00:16:24,270 of the ah herbal compounds some of the organic farming compounds so these may be producing 147 00:16:24,270 --> 00:16:32,820 less waste coming out of the system then we are very strong surfactants and detergents 148 00:16:32,820 --> 00:16:38,769 and other other products which may be having a higher effect on the environment 149 00:16:38,769 --> 00:16:48,170 so you may ah ah phase out the ah artificial materials by more natural materials and you 150 00:16:48,170 --> 00:16:55,800 may do selective ah reuse of these materials as well ah again lets take an example you 151 00:16:55,800 --> 00:17:04,140 have a person who is making uh ah a packaging material now if the packaging material is 152 00:17:04,140 --> 00:17:07,929 recyclable is it better or is it worse is better 153 00:17:07,929 --> 00:17:19,260 is better so glass bottles are better than tin cans you remember a time when all the 154 00:17:19,260 --> 00:17:22,789 beverages used to come in glass bottles 155 00:17:22,789 --> 00:17:28,670 and what used to happen all the glass bottles used to be collected back why because you 156 00:17:28,670 --> 00:17:34,049 could just wash them and refill them now what is it we have got plastic bottles in tin cans 157 00:17:34,049 --> 00:17:40,050 and do we give it back to the shopkeeper we toss it as if ah into the dustbin as if by 158 00:17:40,050 --> 00:17:45,330 some magic [laughter] they will disappear so selectively reuse means use a packaging 159 00:17:45,330 --> 00:17:53,600 materials which can be used and many countries are now making this last legislation the packaging 160 00:17:53,600 --> 00:17:58,080 material will have to be taken back by the manufacturer otherwise you have to pay a tax 161 00:17:58,080 --> 00:18:03,230 why should the municipality take care of the packaging material so maybe we will go back 162 00:18:03,230 --> 00:18:10,880 to glass bottles or maybe if you have plastic bottles please take back your plastic bottles 163 00:18:10,880 --> 00:18:15,520 and recycle them wash them clean them and recycle them 164 00:18:15,520 --> 00:18:20,710 so thats how you reduce waste at source in some of the developed societies a huge debate 165 00:18:20,710 --> 00:18:27,240 is on on the responsibility of the manufacturers then as i said resource recovery through recycling 166 00:18:27,240 --> 00:18:34,790 its easier said than done recycling is not that simple you have to keep each item separately 167 00:18:34,790 --> 00:18:43,220 virtually the more segregated you are the more ah you can reuse it now in a country 168 00:18:43,220 --> 00:18:47,400 like india where the kabadi wala comes to your house you can take into each individual 169 00:18:47,400 --> 00:18:53,450 item he will take the the glass bottle separately he will take the tin can separately he will 170 00:18:53,450 --> 00:18:59,940 take the newspaper separately he will he will take ah each individual but in a in a more 171 00:18:59,940 --> 00:19:04,770 industrialized society where everything is mechanized the tendency is you can keep them 172 00:19:04,770 --> 00:19:08,050 separate but somebody is going to come and collect them a machine or a truck will come 173 00:19:08,050 --> 00:19:13,080 and collect them now if you have ten bins it is not only about 174 00:19:13,080 --> 00:19:16,210 keeping them separately you should be able to collect them and take them to different 175 00:19:16,210 --> 00:19:21,840 places for doing different things of them so the the weakest ah link in the chain is 176 00:19:21,840 --> 00:19:26,480 one the householder may not keep them separately is too lethargic or lazy to keep same things 177 00:19:26,480 --> 00:19:32,330 separately the second is even if he does you may not be able to set up ten streams for 178 00:19:32,330 --> 00:19:37,200 collecting different component of the waste because too expensive 179 00:19:37,200 --> 00:19:45,160 so nevertheless this is the area which requires the strongest funding other than waste reduction 180 00:19:45,160 --> 00:19:49,970 at source you do separate storage so now some countries are five bin system we are going 181 00:19:49,970 --> 00:19:54,660 we are trying to go from one bin to the two bin briery size dry waste and wet waste but 182 00:19:54,660 --> 00:20:00,150 there are some countries which are five i mean there is a hazardous waste which comes 183 00:20:00,150 --> 00:20:06,679 out from the paints nail polish removers lead acid batteries they come out from the household 184 00:20:06,679 --> 00:20:12,470 the medicine so you have to have a hazardous waste bin then you have to have a recyclables 185 00:20:12,470 --> 00:20:18,340 bin the paper or the other stuff then you have a food waste bin then you have a metals 186 00:20:18,340 --> 00:20:22,090 and electronic metals bin then you have an electronics bin 187 00:20:22,090 --> 00:20:28,210 so you have five bins adoption is not very high still in these various countries but 188 00:20:28,210 --> 00:20:35,570 they are trying to go towards that system then once you are taking these you have to 189 00:20:35,570 --> 00:20:41,110 process these and remanufacture its not just you will take metal and it will get recycle 190 00:20:41,110 --> 00:20:50,360 you have to go through a process of removing the paint making a new a can out of it or 191 00:20:50,360 --> 00:20:56,270 if you have a plastic bag you can melt it and reuse it but the recycle bag how do you 192 00:20:56,270 --> 00:21:00,530 know you are using a recycle bag what is the colour of a recycled plastic bag 193 00:21:00,530 --> 00:21:09,350 green very ambitious which is the color which is 194 00:21:09,350 --> 00:21:16,650 the easiest to manufacture why it is the most difficult 195 00:21:16,650 --> 00:21:19,400 black black black so all the black black tallies 196 00:21:19,400 --> 00:21:25,220 that you get for putting your garbage in it progressively the color which is mixed with 197 00:21:25,220 --> 00:21:29,970 the plastic keeps on making the bag darker and darker and eventually the recycled plastic 198 00:21:29,970 --> 00:21:36,880 looks black so remember that in all probability the transparent 199 00:21:36,880 --> 00:21:41,049 or the white plastic is the original plastic and the recycled plastic is black so you can 200 00:21:41,049 --> 00:21:48,419 recycle it but how much can you keep the color away from the plastic and all these materials 201 00:21:48,419 --> 00:21:55,630 can be recycled and of course if i want to ah do further recovery i mean our food waste 202 00:21:55,630 --> 00:22:04,030 i cant recycle food but ah you can send it i mean the hostel food where does it go the 203 00:22:04,030 --> 00:22:13,299 food waste from the hostels all the food which is leftover if the food is left there two 204 00:22:13,299 --> 00:22:18,990 kinds of waste one is the excess food so in the excess food can always be sent to a underprivileged 205 00:22:18,990 --> 00:22:24,091 you can work out a mechanism that it can reach the underprivileged people but if the waste 206 00:22:24,091 --> 00:22:29,530 which has gone into the dustbin where does it go 207 00:22:29,530 --> 00:22:34,730 it can go to a piggery a pigs can eat it or animals can eat it but then again you need 208 00:22:34,730 --> 00:22:38,860 a separate collection and transportation and delivery system you may be here and the pigs 209 00:22:38,860 --> 00:22:47,971 may be twenty five kilometers away right so anyways after ah recycling and reuse you can 210 00:22:47,971 --> 00:22:54,380 do re ah processing so you can convert your municipal solid waste into compost by aerobic 211 00:22:54,380 --> 00:23:03,160 processes and anaerobic digestion you can do biomethanation a methane can give you energy 212 00:23:03,160 --> 00:23:07,650 you can do thermal treatment you can burn it you can from the municipal solid waste 213 00:23:07,650 --> 00:23:12,340 you can take out the paper and the plastic and the rags for refuse derived fuel which 214 00:23:12,340 --> 00:23:18,010 can be used for energy recovery if you have ash if you have construction and demolition 215 00:23:18,010 --> 00:23:25,710 waste and you use it from building blocks can you use the ash in roads and embankments 216 00:23:25,710 --> 00:23:31,530 if its not hazardous instead of using earth which you will dig up from some farmers place 217 00:23:31,530 --> 00:23:36,919 can you do that and you can also do some chemical treatment for recovery of compounds 218 00:23:36,919 --> 00:23:43,710 so all these resource recovery processes require more investments in terms of giving energy 219 00:23:43,710 --> 00:23:49,660 and materials to make this happen but in the end the recovery bills do outweigh the investments 220 00:23:49,660 --> 00:23:55,530 which are made after this we may want to we may still have 221 00:23:55,530 --> 00:24:00,380 some waste left and we might want to transform the waste for example you might want to shred 222 00:24:00,380 --> 00:24:04,900 the waste to make it into smaller you have large sized waste you can shred it or you 223 00:24:04,900 --> 00:24:13,920 can grind it you can do size separation through screening mixed waste is coming to you to 224 00:24:13,920 --> 00:24:22,260 a site you do screening the waste which is more than ah what is the signs how many mm 225 00:24:22,260 --> 00:24:26,580 is this or how many centimeters of this 226 00:24:26,580 --> 00:24:32,440 yeah so lets say this is four inches four inches how many mm 227 00:24:32,440 --> 00:24:36,170 so anything about hundred mm maybe it will be only c and d waste which was mixed wrongly 228 00:24:36,170 --> 00:24:41,000 so we can do screening and from the screening you can transform the waste by getting separate 229 00:24:41,000 --> 00:24:47,060 fragments you can do volume reduction your waste is very loose you can send it through 230 00:24:47,060 --> 00:24:53,820 compactors to reduce the bail them and to make them into ah denser arrangement you can 231 00:24:53,820 --> 00:25:01,200 stabilize the waste the waste is hazardous you can mix it with sainly cement and lime 232 00:25:01,200 --> 00:25:08,000 such that the ah toxicity goes down because the cement will react with the matrix and 233 00:25:08,000 --> 00:25:13,610 when you do a leaching test that much hazardous material will not come out and you can also 234 00:25:13,610 --> 00:25:19,650 do encapsulation that means you are very toxic waste you can embedded in the middle of a 235 00:25:19,650 --> 00:25:26,230 brick or into a glassy matrix so that it does not come out 236 00:25:26,230 --> 00:25:33,549 so waste transformation is the next step after waste processing and then finally of course 237 00:25:33,549 --> 00:25:39,530 you will do the disposal online so for the solid waste that cannot be recycled a processed 238 00:25:39,530 --> 00:25:46,530 you see every waste when it goes to a plant dont think it vanishes suppose waste goes 239 00:25:46,530 --> 00:25:51,679 to an incineration plant and they will burn it firstly the incineration plant paulo will 240 00:25:51,679 --> 00:25:57,960 say i cant take all the waste i will do pre processing so he will do pre processing he 241 00:25:57,960 --> 00:26:02,720 will remove the construction in the demolition debris which is mixed with all kinds of stuff 242 00:26:02,720 --> 00:26:06,390 he will take the final fraction he will burn it ash will come out 243 00:26:06,390 --> 00:26:11,250 so some of the waste will get processed and reused but there will be rejects so from each 244 00:26:11,250 --> 00:26:18,050 plant you get rejects the rejects have to come for disposal to the land so waste does 245 00:26:18,050 --> 00:26:26,570 not vanish if you send it for processing some reject still come back to you all the time 246 00:26:26,570 --> 00:26:30,799 so for the solid waste that cannot be recycled a process you will dispose on land and for 247 00:26:30,799 --> 00:26:35,030 the residual waste after all types of processing have been undertaken that means all the rejects 248 00:26:35,030 --> 00:26:44,120 coming out of the various plots and this is an interesting table we will come back to 249 00:26:44,120 --> 00:26:47,850 this first so there are two components of the waste which is disposed of on land that 250 00:26:47,850 --> 00:26:53,120 waste which cannot be ah used for anything so the waste is very intricately mixed and 251 00:26:53,120 --> 00:26:57,340 you can see the components on it you know but you know you have a tea bag mixed with 252 00:26:57,340 --> 00:27:02,360 your food waste mixed something else i mean unless you actually go into it cut the tea 253 00:27:02,360 --> 00:27:07,110 bag and remove the stuff you know you have you have your waste which is in a plastic 254 00:27:07,110 --> 00:27:10,980 bag and the plastic bag is closed from the top and dumped into them unless you to shred 255 00:27:10,980 --> 00:27:15,221 the plastic bag you cant go inside to remove wastes inside it its complex the more you 256 00:27:15,221 --> 00:27:20,320 mix the waste the more useless it becomes its no not possible to get the constituents 257 00:27:20,320 --> 00:27:25,730 back again from it so there will be waste which cannot be recycled 258 00:27:25,730 --> 00:27:31,080 or processed all industry will say this is not good enough for me and those which can 259 00:27:31,080 --> 00:27:34,940 be recycled and processed there will give you residual waste that will also come to 260 00:27:34,940 --> 00:27:43,460 the land so if i look at the ah type of waste which is ah um coming out in different countries 261 00:27:43,460 --> 00:27:50,340 this is the ah components you know in this is municipal solid waste paper plastic metals 262 00:27:50,340 --> 00:27:57,309 glass rubber leather and textiles wood biodegradable inerts other so first remember inerts is not 263 00:27:57,309 --> 00:28:00,659 like true inerts its like construction and demolition waste 264 00:28:00,659 --> 00:28:07,200 so if i see india here and if i see us uk europe you find lot of paper and cardboard 265 00:28:07,200 --> 00:28:12,659 here but not here and the answer to that is the kabadi wala system the household collection 266 00:28:12,659 --> 00:28:19,870 individual collection system our paper goes to that plastics are similar nobody wants 267 00:28:19,870 --> 00:28:24,890 these fine glass specially these thin bags they are very very very very little recyclable 268 00:28:24,890 --> 00:28:29,500 value anything which are the recyclable value will be taken away so metals also you find 269 00:28:29,500 --> 00:28:38,250 in india they go down glass also in india your beer bottles or your any other bottles 270 00:28:38,250 --> 00:28:44,240 they go down so rubber leather and textiles i think is underreported in india we think 271 00:28:44,240 --> 00:28:49,549 this is higher this would also be about five to six or nine percent in india especially 272 00:28:49,549 --> 00:28:55,770 the garage which are there wood is also had in fact these figures are probably a little 273 00:28:55,770 --> 00:29:01,840 under reported but nevertheless we will take them at this value but suddenly you find because 274 00:29:01,840 --> 00:29:07,670 there are so many other things in the waste of other countries the biodegradable component 275 00:29:07,670 --> 00:29:17,010 is a little low right whereas in india the other components have been reduced by the 276 00:29:17,010 --> 00:29:22,760 kabadi wala therefore the biodegradable components are high 277 00:29:22,760 --> 00:29:27,300 so indian waste is the wet waste its called the lot of food waste in comparison to other 278 00:29:27,300 --> 00:29:33,710 countries and if you have a lot of paper and cardboard and plastics you can burn that it 279 00:29:33,710 --> 00:29:38,870 will give you energy if you do proper control for dioxins and everything but if you have 280 00:29:38,870 --> 00:29:45,251 low quantity then it may not give you energy unless you segregate so and the other thing 281 00:29:45,251 --> 00:29:49,870 which you see very high in india is the construction and demolition waste in the developed world 282 00:29:49,870 --> 00:29:55,039 there is a separate stream for collecting this and this is a well set out industry you 283 00:29:55,039 --> 00:30:00,659 will recycle your c and d waste you have c and d waste processing plants where as in 284 00:30:00,659 --> 00:30:04,720 india we are just starting so at the moment almost all the waste which comes as about 285 00:30:04,720 --> 00:30:09,640 twenty five percent construction and demolition waste 286 00:30:09,640 --> 00:30:18,140 any observations on this table anything you had like to discuss 287 00:30:18,140 --> 00:30:25,360 any clarifications ok if you have a high biodegradable fraction the optimum route is to do a biological 288 00:30:25,360 --> 00:30:32,820 treatment and the optimum route is basically composting here if you have high combustible 289 00:30:32,820 --> 00:30:41,860 fraction the optimum route is to go for energy recovery by thermal treatment that means incineration 290 00:30:41,860 --> 00:30:49,350 you burn the combustible material if you have high inert content do physical treatment make 291 00:30:49,350 --> 00:30:55,950 building blocks make embankments so you these are the broad guidelines which 292 00:30:55,950 --> 00:31:07,490 we have and the important thing is if the waste has been stored separately into the 293 00:31:07,490 --> 00:31:16,770 separate fractions and if you have the streams to collect that we can we can use it for the 294 00:31:16,770 --> 00:31:22,720 purpose however if all these components become mixed with each other all these components 295 00:31:22,720 --> 00:31:28,720 become mixed with each other then it has no value and an important example is that about 296 00:31:28,720 --> 00:31:34,799 twenty five thirty years ago ah oh the first waste to energy plant was set up in delhi 297 00:31:34,799 --> 00:31:40,770 by oh international funding but nobody realized that this that the technology that they were 298 00:31:40,770 --> 00:31:46,900 using was coming from europe and the us but the nobody realized that we have no energy 299 00:31:46,900 --> 00:31:59,029 content and you know this this error can be made if your sample size is not large typically 300 00:31:59,029 --> 00:32:02,230 if you want to find the energy content of municipal solid waste what should be our sample 301 00:32:02,230 --> 00:32:06,490 size in soil mechanics what is your sample size 302 00:32:06,490 --> 00:32:12,460 if you want to do liquid limit plastic limit how many grams 303 00:32:12,460 --> 00:32:18,100 thirty grams well later i take hundred grams be on the 304 00:32:18,100 --> 00:32:25,760 safe side hundred grams will come in in my hand now i am trying to make you visualize 305 00:32:25,760 --> 00:32:32,500 you want to ah characterize municipal solid waste what should be the size of your sample 306 00:32:32,500 --> 00:32:39,590 in terms of volume or in terms of weight the hundred grams you you want to take one kilogram 307 00:32:39,590 --> 00:32:46,260 is that a good size to 308 00:32:46,260 --> 00:32:53,380 anybody hundred grams was for soil two hundred grams for a tri axial test two kilograms for 309 00:32:53,380 --> 00:32:58,270 a proctor test thats the kind of sample size that we are talking about how much for a municipal 310 00:32:58,270 --> 00:33:03,919 solid waste 311 00:33:03,919 --> 00:33:07,679 well i would like to take the municipal solid waste which is at least one cubic meters one 312 00:33:07,679 --> 00:33:16,210 meter by one meter by one meter why because its very heterogeneous it might have a huge 313 00:33:16,210 --> 00:33:18,330 boulder it might have a ah 314 00:33:18,330 --> 00:33:23,881 a broken piece of your window a broken piece of your chair so it might have large size 315 00:33:23,881 --> 00:33:28,520 material so if you take hundred grams and go and do the energy content your reading 316 00:33:28,520 --> 00:33:32,620 is not likely to be correct so one of the reasons at that time i think there was an 317 00:33:32,620 --> 00:33:36,600 error was that the sampling was not large enough to represent the energy content of 318 00:33:36,600 --> 00:33:42,890 total waste so plant was set up and it never was able to recover energy 319 00:33:42,890 --> 00:33:48,470 from it so its important to understand that if you 320 00:33:48,470 --> 00:33:54,810 store things separately and if your energy content is good you can get energy out of 321 00:33:54,810 --> 00:33:59,670 it mixed waste really has no value can we unmixed it the question always there is can 322 00:33:59,670 --> 00:34:05,419 we unmixed waste yes i can grossly unmixed waste i can do screening i can do magnetic 323 00:34:05,419 --> 00:34:14,169 separation i can do air separation but i cannot intimately unmixed it i cannot remove the 324 00:34:14,169 --> 00:34:20,409 tea from the tea bag and say my paper is here and my tea is here or the thread is here 325 00:34:20,409 --> 00:34:24,899 so unmixing is difficult 326 00:34:24,899 --> 00:34:32,339 separation or sorting of mixed waste is tedious separation of its expensive and often non 327 00:34:32,339 --> 00:34:37,389 executable so separation of the source is most derive ah desirable but that depends 328 00:34:37,389 --> 00:34:42,020 on the person who is producing the waste and secondly it depends on who is going to collect 329 00:34:42,020 --> 00:34:48,240 the separate streams the municipality is therefore must have the separate systems for collecting 330 00:34:48,240 --> 00:34:53,190 and working on that that means if i want your construction and demolition waste separately 331 00:34:53,190 --> 00:34:59,410 i must be able to get it from you and my stream must go to a c and d plan 332 00:34:59,410 --> 00:35:04,080 the other issue is that if there are some hazardous components if you mix your hazardous 333 00:35:04,080 --> 00:35:11,310 components into your non hazardous waste you render it hazardous so presence of hazardous 334 00:35:11,310 --> 00:35:15,920 components render the end products of processing to be of limited use let me see i will see 335 00:35:15,920 --> 00:35:21,190 a i will look a i will look composting to my biodegradable fraction of municipal solid 336 00:35:21,190 --> 00:35:29,760 waste now the compost must meet my standards set up for applying of fertilizers and composed 337 00:35:29,760 --> 00:35:33,570 to crops to grow crops which are going to be consumed by you and me 338 00:35:33,570 --> 00:35:39,720 so the compost must have heavy metals within a limit and certain other things within some 339 00:35:39,720 --> 00:35:45,700 limits now if you all if you by mistake mix up the waste and make a compost of mixed waste 340 00:35:45,700 --> 00:35:51,260 it may not meet the standards so it may meet the standards in the in the in the industrialized 341 00:35:51,260 --> 00:35:57,310 world there are separate standards for compost which can be used for flowers and gardens 342 00:35:57,310 --> 00:36:02,950 which are not going to enter the human chain whether we the compost which can be used for 343 00:36:02,950 --> 00:36:08,050 crops which are going to be consumed by human beings so maybe the compost might meet a lower 344 00:36:08,050 --> 00:36:13,240 standard but the very stringent standards you then should be very clear that there should 345 00:36:13,240 --> 00:36:19,440 be no hazardous component to it and the more processing devices that you set 346 00:36:19,440 --> 00:36:27,400 up the more is the odour issue that you are handling always has a smell you go to any 347 00:36:27,400 --> 00:36:31,470 area you go to an industrial area and you start getting a particular smell in the indust 348 00:36:31,470 --> 00:36:38,640 in the air and that that is the smell because of the gases coming out of the chimneys and 349 00:36:38,640 --> 00:36:43,810 you go to the waste dump and that smell will be all pervasive now you say i will send this 350 00:36:43,810 --> 00:36:50,020 for waste to energy i will send this for composting wherever you send it you create more odour 351 00:36:50,020 --> 00:36:56,430 whenever you send it you create more odour and then you have to do the odour control 352 00:36:56,430 --> 00:37:02,580 so pollution control measures are necessary at all treatment plants when you keep on hearing 353 00:37:02,580 --> 00:37:08,810 about some residents being up in arms against the waste to energy plant ah in okla or the 354 00:37:08,810 --> 00:37:13,190 composting plant in the newspapers every now and then why because they are bothered by 355 00:37:13,190 --> 00:37:19,030 the odour so ideally these should be far away typically odour will travel three to five 356 00:37:19,030 --> 00:37:26,260 kilometres from a facilely either you should have very stringent odour control ah mechanisms 357 00:37:26,260 --> 00:37:33,400 which are expensive or the you should be far away so this have to be taken into account 358 00:37:33,400 --> 00:37:41,430 so all that we are saying is that this integrated solid waste management is very important it 359 00:37:41,430 --> 00:37:45,670 can be done at the household level which is the best but then you are dealing with tens 360 00:37:45,670 --> 00:37:53,330 of thousands of people and making them ah you know fall in line it can be done at the 361 00:37:53,330 --> 00:37:59,300 community level you may say all right i will not do so much at the household level i i 362 00:37:59,300 --> 00:38:05,980 would like to do composting at the community level or waste to energy of my society i will 363 00:38:05,980 --> 00:38:11,020 do bio mechanization and take the methanol or it can be done at a central level in a 364 00:38:11,020 --> 00:38:15,280 city or it can be done at a central level in the city 365 00:38:15,280 --> 00:38:22,910 so ah for the big cities for the big cities ah a lot of demand for centralized facilities 366 00:38:22,910 --> 00:38:28,109 which should be a little away from the city and we should do everything in a mechanised 367 00:38:28,109 --> 00:38:35,260 manner but in the smaller cities one can look at household and community level initiatives 368 00:38:35,260 --> 00:38:41,810 so the ultimate integrated solid waste management system comes in looking at the alternatives 369 00:38:41,810 --> 00:38:50,610 at all these three three levels and then arriving at the solutions ah ah for your integrated 370 00:38:50,610 --> 00:38:55,070 solid waste if you invest in all this then the amount 371 00:38:55,070 --> 00:39:01,380 of waste reaching the land is lesser so lets land area is used and the height of the dumps 372 00:39:01,380 --> 00:39:12,210 becomes smaller so ah we will carry on this discussion ah about ah about this integrated 373 00:39:12,210 --> 00:39:17,740 waste management by looking at some recent initiatives which we have started we look 374 00:39:17,740 --> 00:39:22,830 at some examples where this is working ah beg beginning to make an impact and the waste 375 00:39:22,830 --> 00:39:30,520 reaching the ah sites is reduced but for today we will ah stop at this ah juncture and i 376 00:39:30,520 --> 00:39:39,820 will be happy to take ah any questions ah that you may have ah ah at the stage 377 00:39:39,820 --> 00:39:45,839 so we started with the thought that can we have a zero waste society so after this discussion 378 00:39:45,839 --> 00:39:53,130 how many of you think we can have a zero waste society where is your hands we are a class 379 00:39:53,130 --> 00:39:57,780 of fifteen let me see how many hands think one of us thinks that we can have a zero waste 380 00:39:57,780 --> 00:40:05,510 society wonderful how many of us think that we can have a low waste society low waste 381 00:40:05,510 --> 00:40:11,530 so fourteen out of fifteen thinks that we can have a low waste society and what is low 382 00:40:11,530 --> 00:40:17,610 if today we are producing hundred units of waste our target should be that that hundred 383 00:40:17,610 --> 00:40:27,170 should become fifty in the near term and perhaps twenty five in the long term and by that time 384 00:40:27,170 --> 00:40:32,700 maybe some treatment techniques would have come a low cost low energy treatment techniques 385 00:40:32,700 --> 00:40:42,050 where we can actually ah make all the waste disappear and then we can have a zero waste 386 00:40:42,050 --> 00:40:47,060 society as ah one or some of us are optimist about it 387 00:40:47,060 --> 00:40:50,460 but you know you keep on reading about these experiments that people live together for 388 00:40:50,460 --> 00:40:57,160 three sixty five days in a dome and they wanted to see whether they can live without energy 389 00:40:57,160 --> 00:41:00,650 and without 390 00:41:00,650 --> 00:41:05,829 raw materials from outside how many of you saw the movie the martian in that martian 391 00:41:05,829 --> 00:41:08,730 also he has to set up an ecosystem 392 00:41:08,730 --> 00:41:16,350 where he has to sustain himself without energy and without raw materials from outside thats 393 00:41:16,350 --> 00:41:23,420 the dream that will be a zero waste society and there will be no waste till that time 394 00:41:23,420 --> 00:41:27,170 environmental geo technology or geo environmental engineering we will continue to remain a important 395 00:41:27,170 --> 00:41:30,150 subject and we will discuss that in the next class 396 00:41:30,150 --> 00:41:30,539 thank you