- Email: [email protected]
Impact of climatic conditions and socio-economic status on solid waste characteristics: a case study
The Scieace of the Total Environment, 136 (! 993) 143-153 Elsevier Science Publishers B.V., Amsterdam
143
Impact of climatic conditions and socio-economic status on solid waste characteristics: a case study Gopal Dayal, Alka Yadav, R.P. Singh and R. Upadhyay* Department of Chemistry, St. John's College, Agra-282002. India (Received December 9th, 1991; accepted May 20th, 1992)
ABSTRACT The impact of climatic conditions and socio-economic status on solid waste characteristics at Agra city during 1989-90 is discussed. The city was divided, occupation-wise, into residential, commercial and industrial areas following the 'Stratified Random Sampling Technique'. Four hundred and fifty samples were analysed to compare the average values of various physical and chemical properties of solid wastes produced by different sub-groups in different seasons. The paper concludes with recommendations and suggestions for a better management of Agra city refuse.
Key words: climatic conditions: socio-economic sta2us; relative costs: solid waste characteristics and management; Agra city
INTRODUCTION
Refuse characteristics differ from country to country, city to city and even from street to street. The socio-economic statu~' and socio-cultural factors of the inhabitants within a city affect the refuse l~roperties in different ways. Further, refuse properties also vary with season, depending upon the availability of fresh fruits, vegetables, holidays and tourism. Finally, refuse and its composition change over the years wit.h variations in prosperity, food habits, literacy, use of disposable paper and plastic products. For a particular city, if all these factors remain constant, it is the climatic conditions which may cause alterations in refuse characteristics in different seasons, i.e. summer, monsoon and winter, as temperature, humidity and rainfall are entirely different during these seasons. Agra (lat. 27°10 ' N and long. 70 ° 3'E), popularly known as the City of *Assistant ScientificOfficer, U.P. Pollution Control Board, Bareilly, India. 0048-9697/93/$06.00 © 1993 Elsevier Science Publishers B.V. All rights reserved
144
O. DAYAL ET AL.
Taj, with a population of about I million is cosmopolitan in nature. The city is located in the semi-arid southern part of the Upper Gangetic Plain of North India. The municipal corporation is scattered over an area of 63 km 2. The population produces a large quantity of solid wastes which can be seen in the form of piles along road-sides and streets, thus spoiling the beauty of the city and adding contamination to surface water and groundwater sources. The problem is aggravated with an increase in population as more and more people are migrating from rural areas to the city. A large number of tourists also visit the city everyday further deteriorating the situation. It is imperative to know the characteristics of city refuse to develop proper strategies for their safe and hygienic disposal and to design a better disposal system. For example, the design of a waste-to-energy facility will require detailed information on the amount and composition (e.g., calorific value) of the waste to be handled. Similarly waste stream assessment to support the development of a major recycling programme should also deliver specific information such as quantities of recyclable materials and their sources. The present investigation aims at evaluating the impact of climatic conditions and socio-economic status on refuse characteristics and to propose ~uitable measurements for a better management of Agra city refuse.
EXPERIMENTAL
1. Selection of sites After an initial reconnaissance of the municipal area of the city, the different areas were classified occupation-wise as residential, commercial and industrial areas. The residential areas were further divided into high income, middle income, low income and slum groups. Fifty sampling points were selected in such a way as to be truly representative of the contributing population scattered all over the city limits. One hundred and fifty samples for each season, i.e. 3 samples were collected from each point. These points include disposal sites as during the survey it was observed that some refuse ingredients are salvaged enroute to the disposal site.
Z Frequency of sampling The sampling was carried o ~ each day for I week. Samples were collected everyday from sampling points belonging to different occupation groups. The number of samples collected from a given category was always selected to be more than the minimum recommended by Carruth and Klee [I].
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
145
3. Analysis The samples collected were sorted out physically into different components (Table 1) while the chemical analysis was performed following the standard methods [2-4]. The calorific value of the refuse was determined in accordance with the method prescribed by the Bureau of Indian Standards [5]. The pH was determined in a 1:5 soil suspension.
4. Calculation The refuse characteristics from various sub-groups were averaged and then by using a weightage factor from the total refuse produced by these subgroups the characteristics for the entire city refuse were calculated. The factor was equal to the total weight produced by the given sub-group to the total weight produced by the city as a whole. RESULTS AND DISCUSSION
Physical characteristics Physical properties of various sub-groups of Agra city in different seasons are presented in Table 1 on a wet weight basis. The relative amounts of rubber, leather, plastics and glass are quite small because waste collectors remove them to a considerable extent. However, the high income group provides maximum quantities of these materials as compared with other subgroups in all the seasons. The percentage of paper is more or less the same as that of other substances mentioned in the text above produced by different sub-groups and reaches a peak value in the winter. Similar trends have been detected for rags; the low quantities of these ingredients may be attributed to salvaging by scavengers. The trends in other developing countries appear to be the same. For example, the paper content is low in countries with lower gross n~tional product (GNP) per ca.p;*~a($60-160) and is high when GNP per capita is high as in Singapore ($2700). Plastics and glass contents also show similar trends in Singapore [6]. As expected, the high income group produces maximum amounts of food and vegetable wastes. The values are higher in winter due to availability of larger variety of fruits and vegetables followed by the summer and then the rainy season. Commercial areas produce more or less similar quantities of food and vegetable wastes. The high income group is found to give maximum amounts of grass and leaves which reach their highest values during the rainy season because lawn mowing and trimming is a common feature during this season in Agra. These components can be utilised for yard composting. Over
146
G. O ^ V ^ L ~T AL.
~ ~ ~ ~ ~ ~-~ ~-. ~ ~ ~. ~ ~. - -~ - -~. ~ ~ -~ ~ - ~ ~ ~ ~ ~ ~ ~ ~
. ~ .~
.~
]] ~
m
m
N
•
i N
.
.
~
•
~
~
•
~ ,.~ ~
. ~
.
.
, - :. ~
.
--~
.
Residential (a) High income
I.
Industrial
City as a whole
Dumping grounds
3.
4.
5.
Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy Summer Winter Rain.~ Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy
Seasons
12.23 27.08 32.89 9.38 30.12 34.38 1!.26 29.13 32.81 10.31 29.36 31.98 9.36 29.12 33.34 10.06 28.31 33.69 1!.21 31.36 33.88 9.88 31.06 35.61
7.12 7.81 7.32 7.16 7.13 7.92 8.16 7.96 7.36 8.12 7.38 7.32 7.86 8.01 7.38 7.13 8.06 8.16 7.16 8.05 8.16 8.12 8.10 7.86
Moisture pH
36.31 45.52 27.16 36.01 33.63 31.69 29.68 27.15 29.53 32.87 33.56 27.19 32.37 33.61 30.36 32.01 25.08 20.78 32.36 30.06 25.16 32.63 28.16 26.83
Organic matter
0.68 0.71 0.61 0.72 0.72 0.64 0.60 0.55 0.66 0.63 0.59 0.56 0.71 0.74 0.68 0.69 0.53 0.51 0.65 0.66 0.52 0.67 0.61 0.59
Nitrogen
All values are in percentage by dry weight basis except moisture, pH and C/N ratio.
Commercial
2.
(d) Slum
(c) Low income
(b) Middle income
Type of locality
No.
Chemical characteristics of Agra city refuse during 1989-90
TABLE lI
30.97 37.18 25.83 29.01 27.09 28.72 28.70 28.66 25.95 30.26 33.O0 28.16 26.45 26.34 26.32 26.91 27.45 23.63 28.88 26.42 28.06 28.25 26.77 26.38
C/N ratio
O.69 O.56 0.90 0.62 O.54 0.91 0.71 0.73 0.88 0.56 0.67 0.85 0.65 0.73 O.85 0.73 O.63 O.78 O.65 O,66 O.67 O.68 O.63 0.87 0.51 0.56 0.68 0.71 0.54 0.73 0.53 0.56 0.72 0.63 0.47 0.69 0.71 0.68 0.79 0.58 0.53 0.68 0.59 0.68 0.71 0.55 0.58 0.53
Phosphorous Potassium as P205 as K20
810 818 798 805 835 816 769 801 795 715 796 798 813 799 785 811 856 8O0 817 866 790 756 817 715
Calorific value (kcal/kg)
4~ ....j
m
m
tu- -
f~
148
G. DAVALETAL.
650 yard waste composting facilities are currently in operation in the United States [7]. This method may be very useful. Storm and Finstein [8] have developed categories of yard waste composting that policy makers may find very useful. The high income group is recorded to give maximum compostable fraction in different seasons followed by the commercial areas. These values are higher than those recorded for developing countries [9,10]. It is important to note that values of various constituents of Agra city refuse produced in different seasons seem to remain more or less constant in different seasons. Chemical characteristics Chemical Characteristics of Agra city refuse are given in Table 2. Moisture content was recorded highest during the rainy season followed by winter and summer seasons from all the occupation sub-groups. The pH ranged between 7.12 and 8.16 thereby indicating the alkaline nature of refuse. The high and middle income groups, as well as commercial areas with comparatively higher organic matter content are found to give maximum pH values in the winter season when compared for different seasons in the same sub-group. The results of analysis indicated that the high income group produced maximum amount of organic matter in the summer followed by the winter. Commercial and other sub-groups followed a similar trend. The values of organic matter are in good agreement with the results obtained by Bhide et al. [11] for other Indian cities and are higher than those recorded for cities of developed countries [9,10]. The high organic matter content of Agra city refuse indicates the necessity for its frequent collection and removal. Nitrogen, phosphorous and potassium (NPK) values ranged from 0.58 to 0.81%, 0,56 to 0.87% and 0.47 to 0.79%, respectively. However, no specific trend could be observed when compared for different sub-groups in different seasons, The C/N ratio was found around 30 in different seasons in the case of all sub-groups thereby indicating its suitability for composting [12]. As a resuh ofcomposting waste volume can be reduced to 50-85% [13]. As to the cost factor it may be remarked that mixed fertilizers with NPK in the proper. tion of 12:14:20 is Rs. 1000 tonne. Compost can be sold at Rs. 10 per tonae to the buyers [14]. Chhabaria [15] showed that 14 tonnes of compost would contain almost the same amounts of NPK as 1 tonne of a mixed fertilizer. This means that a farmer will have to spend only Rs. 140 against Rs. 1000 for getting the stipulated amounts of NPK. The combination of calorific value, moisture content and organic matter when plotted on the 'Three Component Diagram' shows that Agra city refuse cannot be subjected to incineration as such (Fig. 1). Auxiliary fuels are needed to be added to sustain the reaction. These values concur the low
! 49
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
100 90 20
80
70
60 SO 40
7(o
30
80
/
0
20
10
20
30
40
50
60
70
80
90
COMBUSTIBLE%
ZONE IN WHICH SELF SUSTAINING COMBUSTION REACTION CAN BE OBTAINED
R
ZONE IN WHICH VALUES FROM AGRA CITY LIE
Fig. I. Three-componentdiagram.
calorific values of 33 Indian cities [l 1] and are much lower than those recorded for refuse from Singapore and Hong Kong [16]. A comparison of Agra city refuse characteristics with other Indian cities and developed countries is given in Table 3, Relative costs and economic aspects of solid wastes
Municipal agencies spend 20-40% of their annual budget on solid waste
150
G. DAYAL ET AL
TABLE III Comparison of some physical and chemical properties of refuse from different cities Characteristic
Agra
Other Indian cities
Developed countries
Paper* Plastic" Metals' Glass' Total compostable matter* Moisture content* Organic matter** C/N ratio Calorific value*' in kcal/kg
3.37 1.46 -0.84 25.06
3-7% 0.5-0.9% 0.4-1.0% 0.3-0.8% 30-50
20-50% !-3% 4-14% 3-100,~ 10-20%
24.49 30.82 28.14 795
20-30% 20-30% 20-30 800-1100
15-30% 15-30% 40-80 2200-3300
*On wet weight basis. **On dry weight basis.
management in developing countries [17]. In India this expenditure is ~ 10% which is US $0.8 to 1.0 per capita per year 1971-73. As estimated, 70-100 million US dollars are being spent annually (1971-73) on solid waste management in urban areas of India [18]. Comparison costs are required to be made before taking any decision regarding solid waste disposal method. For example, cost factors play a decisive role in the choice of collection systems - - whether it should be communal or house.,to-house. It is important to note that cost comparisons are not universal, but must be calculated for each situation, For instance, the portable communal bins are cheaper for refuse removal in comparison to house-to-house collection by truck in India [19]. Similarly Cointreau [17] made a comparison between direct haul or transfer in Nigerian conditions and showed that in that case transfer is cheaper. Likewise tractor and trailers have been found the cheapest for refuse collection and disposal in Sri Lanka among 5 collection vehicle alternatives. The composition of refuse and its handling way affect the socio.economic level of scavengers. It has been observed that scavengers roam around the heaps of solid wastes looking for materials they can sell and in this way refuse composition determines the level of their livelihood. Their salvage work also provides jobs for those who handle the refuse 'downstream'. The other people affected are the labourers involved in refuse collection and disposal, Solid waste management can be very labour intensive work. It is usual for a city to employ between 2 and 5 workers for each 1000 population.
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
151
Three workers/1000 population may represent about 1% of the total national work force. High wage levels in developed countries have compelled the policy makers to introduce, sophisticated machinery. However, where man power is easily available at cheaper rates as in India, it is advisable to adopt strategies that involve more men and fewer machines.
Suggestions and recommendationsfor a better management of Agra city refuse The following points are worth exploring in this regard. (i) Reclamation of plastic, glass, paper, etc., from the waste is recommended as it would not only reduce the volume of waste, but could also be economic because recovered materials can provide jobs in reprocessing (e.g. making shoes from tires or metal goods from tin cans). (ii) Major efforts are needed to encourage the source reduction and resource recovery. A number of organisations [20] have come forward with flow sheets for recovery of various ingredients like glass, metals, etc. (iii) Municipal wastes can be used to produce heat or electricity [21,22]. They typically have a heat of combustion of about 1.2 × 109 J/kg (5000 btu/lb). (iv) Laboratory investigations [23] show that under aerobic conditions, it is possible to convert the insoluble cellulose contained in municipal waste by a cellulolytic bacteria. A 450-kg bullock can synthesise 0.4 kg of protein in 24 h; whereas 450 kg of soybeans can synthesise 36 kg of protein in 24 h. (v) Bio-gas can be obtained from solid wastes under favourable conditions. Extensive laboratory and small scale field studies [24] have been carried out at the National Environmental Engineering Research Institute, Nagpur, India (NEERI) which have yielded interesting results. (vi) It has been suggested [25] and is being suggested that for a better management a National Solid Waste Survey may be carried out and a Solid Waste Disposal Act and also a Resource Recovery Act may be enacted as in some of the develol~d countries of the world.
CONCLUSION
The characteristics of refuse vary significantly depending upon the standard of living and dietary habits of the people. Climatic conditions also affect considerably refuse characteristics such a pH, moisture content and organic matter. We believe that suggestions made by us may be very helpful to decision-makers involved in formulating effective disposal strategies for better management of solid wastes.
152
G. DAYALETAL
REFERENCES 1 D.E. Carruth and A.J. Klee, Analysis of Solid Waste Composition Statistical Technique to Determine Sample Size, Bureau of Solid Waste Management, U.S. Dept. of Health, Education and Welfare, 1969. 2 C.A. Black, Methods of Solid Analysis, Pt. 2, Am. Soc. Agronomy No. 9, Inc. Madison, Wisconia, USA, 1965. 3 C.S. Piper, Soil and Plant Analysis, Academic Press, New York, 1950. 4 M.M. Saxena, Environmental Analysis - - Water, Soil and Air, 2nd edn, Agro Botanical Publishers, India, 1990. 5 Bureauof Indian Standards, Methods for Testing of Coal and Coke, Part !!. Determination of Calorific Value, IS:1350 (Pt. 11), 1970, Fifth Reprint, 1989. 6 B.N, Lohani and N.C, Thanh, Special Problem of Solid Waste Management in Asia, Prec. Seminar on Solid Waste Management, Asian Institute of Technology, Bankok, Sept. 1978, pp. 3-14. 7 J. Glenn and D. Riggle, Where does the waste go?, Biocycle, April (1989) 38. 8 P. Storm and M. Finstein, Leaf Composting Manual for New Jersey Municipalities, New Jersey Dept. of Environmental Protection, Division of Solid Waste Management, Office of Recycling, Trenton, NJ, 1986. 9 F.W. McCamic, Waste Composition Studies: Literautre Review and Protocol, Massachusetts Department of Environmental Management, Bureau of Solid Waste Disposal, October, 1985. 10 EPA, Characterization of Municipal Solid Waste in the United States 1960-2000 (Update 1988), Final Report, U.S.E.P.A., Office of Solid Waste and Emergency Response, Franklin Associates Ltd., March 1988. !1 A.D. Bhide, S.K. Titus, B.Z. Alone, R.C. Dixit, R.V. Bhoyar, L.M. Mothghare, S.S. Gautam and A.D. P:~til, Studies on refuse in Indian ,;ities part II. Variation in quality and quantity, Ind. J. Environ. Health, 15 (1975) 213-222. 12 H.B. Gotass, Composting, WHO Monogr. ser., 31 (1956). 13 A. Taylor and R. Kashmanian, Study and Assessment of Eight Yard Waste Composting Programs Across the United States, EPA, Office of Policy, Planning and Evaluation, Washington, DC, 1988. 14 A.D. Bhide, S.K, Titus, B.Z. Alone, R. Dixit, R.V. Bhoyer, L.M. Mothghare, S.S. Gautam and A.D. Patil, Studies on refuse in Indian cities. Part 111.Cost economics, Ind. J. Environ, Health, 17 (1975) 223-226. 15 N.D. Chhabaria, Utilization of compost as fertilizers. J. Inst. Public Health, 4 (1975) 101-105. 16 N.C. Thanh, P.N. Lohani and C, Tharun, Waste Disposal and Resource Recovery, Proc. Seminar on Solid Waste Management, Asian Institute of Technology, Bankok, September, 1978. 17 SJ. Cointreau, Environmental Management of Urban Solid Wastes in Developing Countries, The World Bank Urban Development Technical Paper No. 5, Washington, DC, 1982. 18 CPHERI Report, Solid Wastes in India, July, 1973. 19 F. Flintoff, Managment of Solid Wastes in Developing Countries, World.Health Organization, New Delhi, 1976. 20 P.M. Sullivan and H.V. Maker, Bureau of Mines Process for Recovering~i,',e:~ourcesfrom Raw Refuse, Proc. 4th Mineral Waste Utilization Symp., Chicago Ill, M~,y 1974, pp. 128-141.
IMPACT OF CLIMATE A N D SOCIO-ECONOMIC STATUS O N SOLID WASTE
153
21 C.K. William, Power from trash, Environment, 16 (1974) 34-38. 22 E.M. Wilson and H.M. Freeman, Processing energy from wastes, Environ. Sci. Technol., 10 (1976) 430-435. 23 C.D. Callihan and C.E. Dunlap, Construction of a Chemical Microbial Pilot Plant for Production of Single Cell Protein from Cellulosic Wastes, Report SW-24c, USEPA, 1971. 24 P.P. Pathe et al. Seasonal variation in performance of anaerobic dig,.-stionof refuse, Ind. J. Environ. Health, 19 (1977) 34-345. 25 R.P. Singh, Solid-waste Characteristics and Pollution in Kanpur City and Preventive Aspects, Ph.D. Thesis, Kanpur Univc~-sity, Kanpur, 1986.
143
Impact of climatic conditions and socio-economic status on solid waste characteristics: a case study Gopal Dayal, Alka Yadav, R.P. Singh and R. Upadhyay* Department of Chemistry, St. John's College, Agra-282002. India (Received December 9th, 1991; accepted May 20th, 1992)
ABSTRACT The impact of climatic conditions and socio-economic status on solid waste characteristics at Agra city during 1989-90 is discussed. The city was divided, occupation-wise, into residential, commercial and industrial areas following the 'Stratified Random Sampling Technique'. Four hundred and fifty samples were analysed to compare the average values of various physical and chemical properties of solid wastes produced by different sub-groups in different seasons. The paper concludes with recommendations and suggestions for a better management of Agra city refuse.
Key words: climatic conditions: socio-economic sta2us; relative costs: solid waste characteristics and management; Agra city
INTRODUCTION
Refuse characteristics differ from country to country, city to city and even from street to street. The socio-economic statu~' and socio-cultural factors of the inhabitants within a city affect the refuse l~roperties in different ways. Further, refuse properties also vary with season, depending upon the availability of fresh fruits, vegetables, holidays and tourism. Finally, refuse and its composition change over the years wit.h variations in prosperity, food habits, literacy, use of disposable paper and plastic products. For a particular city, if all these factors remain constant, it is the climatic conditions which may cause alterations in refuse characteristics in different seasons, i.e. summer, monsoon and winter, as temperature, humidity and rainfall are entirely different during these seasons. Agra (lat. 27°10 ' N and long. 70 ° 3'E), popularly known as the City of *Assistant ScientificOfficer, U.P. Pollution Control Board, Bareilly, India. 0048-9697/93/$06.00 © 1993 Elsevier Science Publishers B.V. All rights reserved
144
O. DAYAL ET AL.
Taj, with a population of about I million is cosmopolitan in nature. The city is located in the semi-arid southern part of the Upper Gangetic Plain of North India. The municipal corporation is scattered over an area of 63 km 2. The population produces a large quantity of solid wastes which can be seen in the form of piles along road-sides and streets, thus spoiling the beauty of the city and adding contamination to surface water and groundwater sources. The problem is aggravated with an increase in population as more and more people are migrating from rural areas to the city. A large number of tourists also visit the city everyday further deteriorating the situation. It is imperative to know the characteristics of city refuse to develop proper strategies for their safe and hygienic disposal and to design a better disposal system. For example, the design of a waste-to-energy facility will require detailed information on the amount and composition (e.g., calorific value) of the waste to be handled. Similarly waste stream assessment to support the development of a major recycling programme should also deliver specific information such as quantities of recyclable materials and their sources. The present investigation aims at evaluating the impact of climatic conditions and socio-economic status on refuse characteristics and to propose ~uitable measurements for a better management of Agra city refuse.
EXPERIMENTAL
1. Selection of sites After an initial reconnaissance of the municipal area of the city, the different areas were classified occupation-wise as residential, commercial and industrial areas. The residential areas were further divided into high income, middle income, low income and slum groups. Fifty sampling points were selected in such a way as to be truly representative of the contributing population scattered all over the city limits. One hundred and fifty samples for each season, i.e. 3 samples were collected from each point. These points include disposal sites as during the survey it was observed that some refuse ingredients are salvaged enroute to the disposal site.
Z Frequency of sampling The sampling was carried o ~ each day for I week. Samples were collected everyday from sampling points belonging to different occupation groups. The number of samples collected from a given category was always selected to be more than the minimum recommended by Carruth and Klee [I].
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
145
3. Analysis The samples collected were sorted out physically into different components (Table 1) while the chemical analysis was performed following the standard methods [2-4]. The calorific value of the refuse was determined in accordance with the method prescribed by the Bureau of Indian Standards [5]. The pH was determined in a 1:5 soil suspension.
4. Calculation The refuse characteristics from various sub-groups were averaged and then by using a weightage factor from the total refuse produced by these subgroups the characteristics for the entire city refuse were calculated. The factor was equal to the total weight produced by the given sub-group to the total weight produced by the city as a whole. RESULTS AND DISCUSSION
Physical characteristics Physical properties of various sub-groups of Agra city in different seasons are presented in Table 1 on a wet weight basis. The relative amounts of rubber, leather, plastics and glass are quite small because waste collectors remove them to a considerable extent. However, the high income group provides maximum quantities of these materials as compared with other subgroups in all the seasons. The percentage of paper is more or less the same as that of other substances mentioned in the text above produced by different sub-groups and reaches a peak value in the winter. Similar trends have been detected for rags; the low quantities of these ingredients may be attributed to salvaging by scavengers. The trends in other developing countries appear to be the same. For example, the paper content is low in countries with lower gross n~tional product (GNP) per ca.p;*~a($60-160) and is high when GNP per capita is high as in Singapore ($2700). Plastics and glass contents also show similar trends in Singapore [6]. As expected, the high income group produces maximum amounts of food and vegetable wastes. The values are higher in winter due to availability of larger variety of fruits and vegetables followed by the summer and then the rainy season. Commercial areas produce more or less similar quantities of food and vegetable wastes. The high income group is found to give maximum amounts of grass and leaves which reach their highest values during the rainy season because lawn mowing and trimming is a common feature during this season in Agra. These components can be utilised for yard composting. Over
146
G. O ^ V ^ L ~T AL.
~ ~ ~ ~ ~ ~-~ ~-. ~ ~ ~. ~ ~. - -~ - -~. ~ ~ -~ ~ - ~ ~ ~ ~ ~ ~ ~ ~
. ~ .~
.~
]] ~
m
m
N
•
i N
.
.
~
•
~
~
•
~ ,.~ ~
. ~
.
.
, - :. ~
.
--~
.
Residential (a) High income
I.
Industrial
City as a whole
Dumping grounds
3.
4.
5.
Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy Summer Winter Rain.~ Summer Winter Rainy Summer Winter Rainy Summer Winter Rainy
Seasons
12.23 27.08 32.89 9.38 30.12 34.38 1!.26 29.13 32.81 10.31 29.36 31.98 9.36 29.12 33.34 10.06 28.31 33.69 1!.21 31.36 33.88 9.88 31.06 35.61
7.12 7.81 7.32 7.16 7.13 7.92 8.16 7.96 7.36 8.12 7.38 7.32 7.86 8.01 7.38 7.13 8.06 8.16 7.16 8.05 8.16 8.12 8.10 7.86
Moisture pH
36.31 45.52 27.16 36.01 33.63 31.69 29.68 27.15 29.53 32.87 33.56 27.19 32.37 33.61 30.36 32.01 25.08 20.78 32.36 30.06 25.16 32.63 28.16 26.83
Organic matter
0.68 0.71 0.61 0.72 0.72 0.64 0.60 0.55 0.66 0.63 0.59 0.56 0.71 0.74 0.68 0.69 0.53 0.51 0.65 0.66 0.52 0.67 0.61 0.59
Nitrogen
All values are in percentage by dry weight basis except moisture, pH and C/N ratio.
Commercial
2.
(d) Slum
(c) Low income
(b) Middle income
Type of locality
No.
Chemical characteristics of Agra city refuse during 1989-90
TABLE lI
30.97 37.18 25.83 29.01 27.09 28.72 28.70 28.66 25.95 30.26 33.O0 28.16 26.45 26.34 26.32 26.91 27.45 23.63 28.88 26.42 28.06 28.25 26.77 26.38
C/N ratio
O.69 O.56 0.90 0.62 O.54 0.91 0.71 0.73 0.88 0.56 0.67 0.85 0.65 0.73 O.85 0.73 O.63 O.78 O.65 O,66 O.67 O.68 O.63 0.87 0.51 0.56 0.68 0.71 0.54 0.73 0.53 0.56 0.72 0.63 0.47 0.69 0.71 0.68 0.79 0.58 0.53 0.68 0.59 0.68 0.71 0.55 0.58 0.53
Phosphorous Potassium as P205 as K20
810 818 798 805 835 816 769 801 795 715 796 798 813 799 785 811 856 8O0 817 866 790 756 817 715
Calorific value (kcal/kg)
4~ ....j
m
m
tu- -
f~
148
G. DAVALETAL.
650 yard waste composting facilities are currently in operation in the United States [7]. This method may be very useful. Storm and Finstein [8] have developed categories of yard waste composting that policy makers may find very useful. The high income group is recorded to give maximum compostable fraction in different seasons followed by the commercial areas. These values are higher than those recorded for developing countries [9,10]. It is important to note that values of various constituents of Agra city refuse produced in different seasons seem to remain more or less constant in different seasons. Chemical characteristics Chemical Characteristics of Agra city refuse are given in Table 2. Moisture content was recorded highest during the rainy season followed by winter and summer seasons from all the occupation sub-groups. The pH ranged between 7.12 and 8.16 thereby indicating the alkaline nature of refuse. The high and middle income groups, as well as commercial areas with comparatively higher organic matter content are found to give maximum pH values in the winter season when compared for different seasons in the same sub-group. The results of analysis indicated that the high income group produced maximum amount of organic matter in the summer followed by the winter. Commercial and other sub-groups followed a similar trend. The values of organic matter are in good agreement with the results obtained by Bhide et al. [11] for other Indian cities and are higher than those recorded for cities of developed countries [9,10]. The high organic matter content of Agra city refuse indicates the necessity for its frequent collection and removal. Nitrogen, phosphorous and potassium (NPK) values ranged from 0.58 to 0.81%, 0,56 to 0.87% and 0.47 to 0.79%, respectively. However, no specific trend could be observed when compared for different sub-groups in different seasons, The C/N ratio was found around 30 in different seasons in the case of all sub-groups thereby indicating its suitability for composting [12]. As a resuh ofcomposting waste volume can be reduced to 50-85% [13]. As to the cost factor it may be remarked that mixed fertilizers with NPK in the proper. tion of 12:14:20 is Rs. 1000 tonne. Compost can be sold at Rs. 10 per tonae to the buyers [14]. Chhabaria [15] showed that 14 tonnes of compost would contain almost the same amounts of NPK as 1 tonne of a mixed fertilizer. This means that a farmer will have to spend only Rs. 140 against Rs. 1000 for getting the stipulated amounts of NPK. The combination of calorific value, moisture content and organic matter when plotted on the 'Three Component Diagram' shows that Agra city refuse cannot be subjected to incineration as such (Fig. 1). Auxiliary fuels are needed to be added to sustain the reaction. These values concur the low
! 49
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
100 90 20
80
70
60 SO 40
7(o
30
80
/
0
20
10
20
30
40
50
60
70
80
90
COMBUSTIBLE%
ZONE IN WHICH SELF SUSTAINING COMBUSTION REACTION CAN BE OBTAINED
R
ZONE IN WHICH VALUES FROM AGRA CITY LIE
Fig. I. Three-componentdiagram.
calorific values of 33 Indian cities [l 1] and are much lower than those recorded for refuse from Singapore and Hong Kong [16]. A comparison of Agra city refuse characteristics with other Indian cities and developed countries is given in Table 3, Relative costs and economic aspects of solid wastes
Municipal agencies spend 20-40% of their annual budget on solid waste
150
G. DAYAL ET AL
TABLE III Comparison of some physical and chemical properties of refuse from different cities Characteristic
Agra
Other Indian cities
Developed countries
Paper* Plastic" Metals' Glass' Total compostable matter* Moisture content* Organic matter** C/N ratio Calorific value*' in kcal/kg
3.37 1.46 -0.84 25.06
3-7% 0.5-0.9% 0.4-1.0% 0.3-0.8% 30-50
20-50% !-3% 4-14% 3-100,~ 10-20%
24.49 30.82 28.14 795
20-30% 20-30% 20-30 800-1100
15-30% 15-30% 40-80 2200-3300
*On wet weight basis. **On dry weight basis.
management in developing countries [17]. In India this expenditure is ~ 10% which is US $0.8 to 1.0 per capita per year 1971-73. As estimated, 70-100 million US dollars are being spent annually (1971-73) on solid waste management in urban areas of India [18]. Comparison costs are required to be made before taking any decision regarding solid waste disposal method. For example, cost factors play a decisive role in the choice of collection systems - - whether it should be communal or house.,to-house. It is important to note that cost comparisons are not universal, but must be calculated for each situation, For instance, the portable communal bins are cheaper for refuse removal in comparison to house-to-house collection by truck in India [19]. Similarly Cointreau [17] made a comparison between direct haul or transfer in Nigerian conditions and showed that in that case transfer is cheaper. Likewise tractor and trailers have been found the cheapest for refuse collection and disposal in Sri Lanka among 5 collection vehicle alternatives. The composition of refuse and its handling way affect the socio.economic level of scavengers. It has been observed that scavengers roam around the heaps of solid wastes looking for materials they can sell and in this way refuse composition determines the level of their livelihood. Their salvage work also provides jobs for those who handle the refuse 'downstream'. The other people affected are the labourers involved in refuse collection and disposal, Solid waste management can be very labour intensive work. It is usual for a city to employ between 2 and 5 workers for each 1000 population.
IMPACT OF CLIMATE AND SOCIO-ECONOMIC STATUS ON SOLID WASTE
151
Three workers/1000 population may represent about 1% of the total national work force. High wage levels in developed countries have compelled the policy makers to introduce, sophisticated machinery. However, where man power is easily available at cheaper rates as in India, it is advisable to adopt strategies that involve more men and fewer machines.
Suggestions and recommendationsfor a better management of Agra city refuse The following points are worth exploring in this regard. (i) Reclamation of plastic, glass, paper, etc., from the waste is recommended as it would not only reduce the volume of waste, but could also be economic because recovered materials can provide jobs in reprocessing (e.g. making shoes from tires or metal goods from tin cans). (ii) Major efforts are needed to encourage the source reduction and resource recovery. A number of organisations [20] have come forward with flow sheets for recovery of various ingredients like glass, metals, etc. (iii) Municipal wastes can be used to produce heat or electricity [21,22]. They typically have a heat of combustion of about 1.2 × 109 J/kg (5000 btu/lb). (iv) Laboratory investigations [23] show that under aerobic conditions, it is possible to convert the insoluble cellulose contained in municipal waste by a cellulolytic bacteria. A 450-kg bullock can synthesise 0.4 kg of protein in 24 h; whereas 450 kg of soybeans can synthesise 36 kg of protein in 24 h. (v) Bio-gas can be obtained from solid wastes under favourable conditions. Extensive laboratory and small scale field studies [24] have been carried out at the National Environmental Engineering Research Institute, Nagpur, India (NEERI) which have yielded interesting results. (vi) It has been suggested [25] and is being suggested that for a better management a National Solid Waste Survey may be carried out and a Solid Waste Disposal Act and also a Resource Recovery Act may be enacted as in some of the develol~d countries of the world.
CONCLUSION
The characteristics of refuse vary significantly depending upon the standard of living and dietary habits of the people. Climatic conditions also affect considerably refuse characteristics such a pH, moisture content and organic matter. We believe that suggestions made by us may be very helpful to decision-makers involved in formulating effective disposal strategies for better management of solid wastes.
152
G. DAYALETAL
REFERENCES 1 D.E. Carruth and A.J. Klee, Analysis of Solid Waste Composition Statistical Technique to Determine Sample Size, Bureau of Solid Waste Management, U.S. Dept. of Health, Education and Welfare, 1969. 2 C.A. Black, Methods of Solid Analysis, Pt. 2, Am. Soc. Agronomy No. 9, Inc. Madison, Wisconia, USA, 1965. 3 C.S. Piper, Soil and Plant Analysis, Academic Press, New York, 1950. 4 M.M. Saxena, Environmental Analysis - - Water, Soil and Air, 2nd edn, Agro Botanical Publishers, India, 1990. 5 Bureauof Indian Standards, Methods for Testing of Coal and Coke, Part !!. Determination of Calorific Value, IS:1350 (Pt. 11), 1970, Fifth Reprint, 1989. 6 B.N, Lohani and N.C, Thanh, Special Problem of Solid Waste Management in Asia, Prec. Seminar on Solid Waste Management, Asian Institute of Technology, Bankok, Sept. 1978, pp. 3-14. 7 J. Glenn and D. Riggle, Where does the waste go?, Biocycle, April (1989) 38. 8 P. Storm and M. Finstein, Leaf Composting Manual for New Jersey Municipalities, New Jersey Dept. of Environmental Protection, Division of Solid Waste Management, Office of Recycling, Trenton, NJ, 1986. 9 F.W. McCamic, Waste Composition Studies: Literautre Review and Protocol, Massachusetts Department of Environmental Management, Bureau of Solid Waste Disposal, October, 1985. 10 EPA, Characterization of Municipal Solid Waste in the United States 1960-2000 (Update 1988), Final Report, U.S.E.P.A., Office of Solid Waste and Emergency Response, Franklin Associates Ltd., March 1988. !1 A.D. Bhide, S.K. Titus, B.Z. Alone, R.C. Dixit, R.V. Bhoyar, L.M. Mothghare, S.S. Gautam and A.D. P:~til, Studies on refuse in Indian ,;ities part II. Variation in quality and quantity, Ind. J. Environ. Health, 15 (1975) 213-222. 12 H.B. Gotass, Composting, WHO Monogr. ser., 31 (1956). 13 A. Taylor and R. Kashmanian, Study and Assessment of Eight Yard Waste Composting Programs Across the United States, EPA, Office of Policy, Planning and Evaluation, Washington, DC, 1988. 14 A.D. Bhide, S.K, Titus, B.Z. Alone, R. Dixit, R.V. Bhoyer, L.M. Mothghare, S.S. Gautam and A.D. Patil, Studies on refuse in Indian cities. Part 111.Cost economics, Ind. J. Environ, Health, 17 (1975) 223-226. 15 N.D. Chhabaria, Utilization of compost as fertilizers. J. Inst. Public Health, 4 (1975) 101-105. 16 N.C. Thanh, P.N. Lohani and C, Tharun, Waste Disposal and Resource Recovery, Proc. Seminar on Solid Waste Management, Asian Institute of Technology, Bankok, September, 1978. 17 SJ. Cointreau, Environmental Management of Urban Solid Wastes in Developing Countries, The World Bank Urban Development Technical Paper No. 5, Washington, DC, 1982. 18 CPHERI Report, Solid Wastes in India, July, 1973. 19 F. Flintoff, Managment of Solid Wastes in Developing Countries, World.Health Organization, New Delhi, 1976. 20 P.M. Sullivan and H.V. Maker, Bureau of Mines Process for Recovering~i,',e:~ourcesfrom Raw Refuse, Proc. 4th Mineral Waste Utilization Symp., Chicago Ill, M~,y 1974, pp. 128-141.
IMPACT OF CLIMATE A N D SOCIO-ECONOMIC STATUS O N SOLID WASTE
153
21 C.K. William, Power from trash, Environment, 16 (1974) 34-38. 22 E.M. Wilson and H.M. Freeman, Processing energy from wastes, Environ. Sci. Technol., 10 (1976) 430-435. 23 C.D. Callihan and C.E. Dunlap, Construction of a Chemical Microbial Pilot Plant for Production of Single Cell Protein from Cellulosic Wastes, Report SW-24c, USEPA, 1971. 24 P.P. Pathe et al. Seasonal variation in performance of anaerobic dig,.-stionof refuse, Ind. J. Environ. Health, 19 (1977) 34-345. 25 R.P. Singh, Solid-waste Characteristics and Pollution in Kanpur City and Preventive Aspects, Ph.D. Thesis, Kanpur Univc~-sity, Kanpur, 1986.