an environmental management method for sugar cane alcohol production in brazil

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Biomass and Bioenergy 25 (2003) 287–299

An environmental management methodfor sugar cane alcohol production in Brazil

M.A.V. Borreroa, J.T.V. Pereirab;∗, E.E. Mirandac

aFederal University of Rondonia, 789000-500, Porto Velho, RO, BrazilbState University of Campinas, P.O. Box 6122, 13083-970, Campinas, SP, Brazil

cEMBRAPA - Environmental Monitoring Center, Campinas, Brazil

Received 26 July 2002; received in revised form 5 December 2002; accepted 24 January 2003

Abstract

This paper presents an environmental management method, focusing on environmental e/ciency for agro-industry. Themain idea is to perform a joint analysis of the ecological, economical and social aspects related to agro-industrial activities.The result of the analysis is a measurement of environmental e/ciency, on a numerical scale. The lower values, encompassing70% of the scale range, classify the low environmental e/ciency activities. The values taking the upper 10% reveal thehigh e/ciency ones. A case study focusing on the Brazilian alcohol production, including the agricultural and industrialphases, is presented. The study emphasizes the impact on the soil, water and air. Moreover, it also deals with the social andeconomic aspects related to the level of employment and productivity. According to the assumptions adopted, none of thethree agro-industries analyzed achieved the highest environmental e/ciency level established.? 2003 Elsevier Ltd. All rights reserved.

Keywords: Environment; Environmental management; Environmental e/ciency; Alcohol; Ethanol; Sugar cane; Biomass; Bioenergy

1. Introduction

The production of alcohol in Brazil was initiatedon a large scale in 1975 in the National program forAlcohol (1975–1985). At present, Brazil produces2:6 × 108 tons of sugarcane, which is processed by324 sugar mills to produce sugar and alcohol. Themid-south region, which corresponds to 17.60% ofthe country’s area, produces 74% of the sugarcaneand has the biggest concentration of these sugar mills,

∗ Corresponding author. Fax: +55-19-3289-3722.E-mail addresses: [email protected] (M.A.V. Borrero),

[email protected] (J.T.V. Pereira), [email protected](E.E. Miranda).

a total of 241 units. The state of Sao Paulo, whichis in this region, has 133 sugar mills and is respon-sible for 76% of the production from the mid-southregion.

In the initial aims of the National Alcohol Program,there was a lack of explicit concern with regard toplanning or environmental impact. This research dealswith the evaluation of environmental aspects in termsof the production of ethanol in Brazil. The objectiveis to propose an evaluation method, which integratesissues such as environmental problems and also con-siders social and economical aspects. The method hasbeen applied to three alcohol mills, which are small,average and large. As a result, an indicator of theenvironmental quality of the work carried out in thefactories, called “environmental performance” that

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288 M.A.V. Borrero et al. / Biomass and Bioenergy 25 (2003) 287–299

points out which and how productive activities canbe improved, was obtained. The relationship betweenfactories and their environmental performance (low,average or high), describes the quality of the re-lationship with the environment. These factoriesshould achieve a high performance category, to in-dicate their high productivity and environmentalquality standards. None of the three mills stud-ied reached the highest environmental performancelevel (A).

2. Environmental performance concept

Many scientiFc reviews Colby [1], Daly [2],Cavalcanti [3] and Pearce [4] discuss in a segmentedand theoretical way, the preservation of the envi-ronment. The great majority point to the social-economical system as being the cause of depredationof environmental resources, but does not oIer anymethodology capable of establishing self-evaluationthat demonstrates a speciFc productive activity andalso its improvement with the environment. Thesediscussions are global in character, but the solution isstill local Costanza [5].

The environmental e/ciency concept Borrero [6]used here deals with the evaluation of production ac-tivities based on economic and environmental criteria.The concept, in terms of the production of alcohol as afuel, also considers the demand for natural resources ameans of production and a receptor of the productionresidues.

Therefore, a high environmental performance ofthis activity is characterized by larger economical pro-ductivity (tons of sugarcane/hectare and/or liters ofalcohol/ton of sugarcane) with lower demand for nat-ural resources, as well as a higher employment level,which is an indicator of social welfare.

3. Evaluation methodology for the environmentalperformance of alcohol production

The production activities related to the use of thesoil for sugarcane cultivation, the use of chemicalinputs, the harvest, the use of liquor in the soil,the transportation of the sugarcane to the factories,the handling of the solid and liquid residues and the

gaseous emissions, the production of alcohol and theproduction of energy from the burning of the bagasse,have been considered to represent the whole alcoholproduction process.

The social and economic aspects such as the cre-ation of jobs and the increase in productivity were alsotaken into account. The methodology to obtain theindicators is explained in Table 1. The classiFca-tion of the indicators was based on alcohol productionfrom 3 case studies in Brazil.

Performances in physical, economical and socialenvironments, for the use of soil, were considered.To determine the performance in the physical envi-ronment, 6 indicators were analyzed: (a) growth ofthe cultivated area, (b) use of the area for the culti-vation of sugarcane, (c) agricultural productivity, (d)environmental damage (incorporation of new environ-mental areas for the cultivation of sugarcane, (e) con-cern about environmental recovery and (f) agriculturalspecialization (single crop use). Each one of theseindicators was classiFed into three groups, as illus-trated for the “growth of cultivated area” index. Theindicator was classiFed as belonging to Group 1 (lowperformance) when the growth of the cultivated areaexceeded 91%, to Group 2 (average performance)when the growth came between 90% and 50% andin Group 3 (high performance) when the growth waslower than 50%.

It can be noted, that in this case (and in some oth-ers), classiFcation involves a certain degree of subjec-tivity, as the authors considered that the growth of thecultivated area, having been carried out mainly by thedisplacement of the other cultivations, would not be adesirable factor. If the growth of the cultivated areashad occurred using abandoned areas of land, the clas-siFcation might have been diIerent. The classiFcationcriteria for each one of the indicators can be obtainedthrough a process of group discussion, involving theentire community. Other indicators such as the perma-nence (years) of chemical inputs in the soil are relatedto more commonly accepted standards, indicating lesssubjectivity in the classiFcation. In the majority of thecases, the comparisons were made in relation to theaverage performance of the Copersucar [7] (The SaoPaulo State Sugar and Alcohol Producer Cooperative)35 sugar and alcohol mills, which are responsible forthe processing of almost a quarter of Brazilian sugar-cane and considered as having the best performance

M.A.V. Borrero et al. / Biomass and Bioenergy 25 (2003) 287–299 289

Table 1ClassiFcation of the environmental performance

Quantifying the environmental Group 1 Group 2 Group 3performance

Soil utilization(1) Performance (a) Growth of the area ¿ 91% 90–49% ¡ 49%of the use of soil (b) Use of the area for ¿ 81% 80% ¡ 79%for sugarcane sugarcane cultivationcultivation on (c) Agricultural productivity (t/ha) Low¡ 66:9 Average 67–80.4 ¿ 80:5land (d) Environmental damage Use of preserved Use of forests and Not

caused by the cultivation of areas other spaces measurablesugarcane(e) Environmental recovery Non-recovery of Recovery of forests Recovery of

forests and other and other spaces preservedspaces areas

(f) Agricultural specialization Large (does not use Average—constant or Low—crop rotation or decreasing increasingalternation)

(2) Performance (a) Dynamics of the activity Decreasing Constant Increasingof the use of soil (b) Agricultural productivity Low¡ 66:9 Average 67–80.4 ¿ 80:5for sugarcane (t/ha)cultivation in an (c) Substitution of other food Substitution of Substitution of one Non-economic crops various cultivations cultivation substitutionenvironment (d) Agricultural specialization Large (no practice of Average—constant or Low—

(crop alternation or rotation) crop rotation) decreasing practice increasing(3) Performance, at (a) Activity dynamics Decreasing Constant Increasingan employment (b) Labor employment index Decreasing Constant Increasinglevel, of the use of for every 1000 harvestedsoil for hectaressugarcanecultivation in asocialenvironment

Chemical inputs(4) Performance, (a) Toxic level of the chemical Large Large Lowon land, of the inputsuse of chemical (b) Permanence of the inputs Large¿ 1 Average = 1 Low¡ 1inputs in the soil in the environment (years)

(c) Use of chemical inputs High—increasing Average—constant Low—index index decreasing

index(d) Agricultural productivity Low¡ 66:9 Average 67–80.4 ¿ 80:5(t/ha)

(5) Performance of (a) Use of chemical inputs High—increasing Average—constant Low—the use of index index decreasingchemical inputs indexin an economic (b) Agricultural productivity Low¡ 66:9 Average 67–80.4 ¿ 80:5environment. (t/ha)

Harvest(6) Performance, (a) Burnt area Large¿ 61% Average = 40–60% Small—39%on land, of (b) Burning practice Large—increasing Average—constant Low—sugarcane or 100% decreasingharvesting (c) Mitigation of burning Low¡ 19% Average = 20–30% High¿ 31%

practice based onmechanization index


Table 1 (continued)


(d) Agricultural productivity Low¡ 66:9 Average—67–80.4 ¿ 80:5(t/ha)

(7) Performance of (a) CO emission with the Large¿ 801 Average—700–800 Low¡ 699sugarcane burning of sugarcane (t/year)harvesting in air (b) Particular material Large¿ 801 Average—700–800 Low¡ 699resources. emission with the burning of

sugarcane (t/year)(c) CH4 emission with the Large¿ 801 Average—700–800 Low¡ 699burning of sugarcane (t/year)

(8) Performance of (a) Loss of alcohol with the Large¿ 3 Average—1–2 Small¡ 1the sugarcane burning of sugarcane (%)harvesting in an (b) Harvester fuel waste (l/t) High¿ 1 Average—0.7–0.99 Low¡ 0:69economical (c) Harvester productivity Low¡ 19 Average 20–50 High¿ 51environment. (1000t/harvesters)(9) Performance of (a) Number of employees per Decreasing Constant Increasingthe harvest in 1000 ha harvesteda social (b) Potential for substituting No mechanization Incipient Increasingenvironment (at men for machines mechanization indexan employmentlevel)

Liquor disposal(10) Performance, (a) Area irrigated with liquor % Low¡ 19 Average 20–35 Large¿ 36on land, of the use (b) Irrigation tendency with Decreasing Constant Increasingof liquor liquor in %

(c) Liquor availability tendency Decreasing Constant Increasingin m3

(d) Liquor application index High¿ 150 Average = 150 Low¡ 150per hectare (m3=ha)(e) Agricultural activity (t/ha) Low¡ 66:9 Average 67–80.4 ¿ 80:5

(11) Performance (a) Co emission due to liquor High¿ 2 Average = 0:5–1 Low¡ 0:49of the transportationtransportation of (b) NOx emission due to High¿ 2 Average = 0:5–1 Low¡ 0:49the liquor in liquor transportation (t/ha)air resources. (c) SOx emission due to liquor High¿ 2 Average = 0:5–1 Low¡ 0:49

transportation (t/ha)(d) Emission of Particulate High¿ 2 Average = 0:5–1 Low¡ 0:49Material due to transport ofliquor (t/ha)

(12) Performance (a) Economy of chemical Low¡ 999 Mean = 1000–2000 High¿ 2001of the fertilizers (t) Average = 1000–2000application of the (b) Fuel expenditure (l/ha) High¿ 100 Average = 95–100 Low¡ 94liquor in an (c) Index for use of chemical Increasing Constant Decreasingeconomical inputsenvironment.(13) Performance (a) CO emissions (sugarcane High¿ 2 Average = 0:5–1 Low¡ 0:49of the t/t)transportation of (b) NOx emissions (sugarcane High¿ 2 Average = 0:5–1 Low¡ 0:49sugarcane in air t/t)resources. (c) SOx emissions (sugarcane High¿ 2 Average = 0:5–1 Low¡ 0:49

t/t)(d) Emissions of Particulate High¿ 2 Average = 0:5–1 Low¡ 0:49Material (sugarcane t/t)


Table 1 (continued)


(14) Performance (a) Number of trucks per 1000 High¿ 8 Average = 4–7 Low¡ 3of the hectares cultivatedtransportation of (b) Fuel expenditure High¿ 1 Average = 0:7–0.99 Low¡ 0:69sugarcane in an (sugarcane l/t)economicalenvironment.

Alcohol production(15) Performance, (a) Use of solid residues in Low¡ 69 Average = 70–90 High¿ 91on land, of the cultivationindustrial process: (b) Area with Flter cake Low¡ 24 Average = 25–35 High¿ 36

application in %incorporation of (c) Area with ash and soot Low¡ 0:99 Average = 1–2 High¿ 3:1solid residues in application in %the factory soil. (d) % sludge applied to land Low¡ 95 Average = 96–99% High 100

(e) Agricultural productivity Low¡ 66:9 Average 67–80.4 ¿ 80:5(t/ha)

(16) Performance (a) Use of water (m3=liter of High¿ 9:1 Average = 8–9 Low¡ 7:9of the industrial alcohol)process in water (b) Residual water outlet (m3=l) High¿ 0:3 Average = 0:11–0.29 Low¡ 0:10resources. (c) Removal of liquid residues High¿ 5% Average 1–4.9 Low = 0

in water streams in (%)(17) Performance (a) CO2 emissions from juice High¿ 0:5 Average = 02–0.49 Low¡ 0:19of the industrial fermentationprocess in air (b) CO2 emissions from the High¿ 0:5 Average = 02–0.49 Low¡ 0:19resources. burning of bagasse

(c) NOx emissions from the High¿ 0:5 Average = 02–0.49 Low¡ 0:19burning of bagasse(d) Emissions of Particulate High¿ 0:5 Average = 02–0.49 Low¡ 0:19Material due to the burning ofbagasse (t/t bagasse)

(18) Performance (a) Sugarcane for the Low¡ 44:9 Average = 45%–55 High¿ 55:01of the industrial production of alcohol (%)process in an (b) Industrial e/ciency l Low¡ 78:9 Average = 79–85.4 High¿ 85:5economical alcohol/ton sugarcane (l/tsc)environment. (c) EIect of the use of solid Low = increasing Average = constant High = decreasing

residues in chemicaldependency(d) EIect of the solid Low¡ 66:9 Average 67–80.4 High¿ 80:5residues in agriculturalproductivity (t/ha)

Energy prod(19) Performance (a) Energy self-su/ciency % Low¡ 94 Average = 95–97 High¿ 80:5of energy (b) Electricity production Low¡ 10:9 Average = 11–14.9 High¿ 15

(kWh/tsc)

production in an (c) Electricity consumption High¿ 11:77 Average = 10:76–11.76 Low¡ 10:75economical (kWh/tsc)environment. (d) Sale of the electric energy Low¡ 0:27 Average = 0:28–0.31 High¿ 0:32

surplus (kWh/tsc)


Table 2Scale of environmental performance and score for productive activity

Productive activities Score Activity production

Minimum Maximum (C) Low (B) Average (A) High

1 Use of soil 12 36 12 to 24 25 to 31 32 to 362 Use of inputs 6 18 6 to 11 12 to 15 16 to 183 Sugarcane harvest 12 36 12 to 24 25 to 31 32 to 364 Use of liquor 12 36 12 to 24 25 to 31 32 to 365 Sugarcane transportation 6 18 6 to 11 12 to 15 16 to 186 Alcohol production 16 48 16 to 33 34 to 43 44 to 487 Energy production 4 12 4 to 7 8 to 10 11 to 12Total 68 204 68 to 142 143 to 183 184 to 204

of the country. This group of indicators is used as abasis for the comparison and evaluation of the infor-mation obtained in the factories. The authors believethat they form a model of environmental relationshipnecessary for mill work. In order to help the analysis,scores were given to the groups, as follows: Group1=1 point, Group 2=2 points and Group 3=3 points.This way, establishing minimum and maximum punc-tuations, for each productive activity, becomes possi-ble. A minimum score occurs when all the indicatorsof a productive activity are in Group 1 and a maxi-mum score occurs when all the indicators are in Group3, as illustrated in Table 2. All indicators were con-sidered to be equally important. Activities which pre-sented low performance (C) were those whose totalscores were less than 70% of the maximum value, av-erage performance (B) were those whose total scoreswere between 70% and 90%, and high performance(A) were those whose total scores were above 90%,as shown in Table 2 (Scale of Environmental Perfor-mance and Score for Productive Activity).

4. Method application

The method was applied to three mills that pro-duce alcohol as fuel in the state of Sao Paulo. Thesewere: The Sao Jose Mill, small capacity (7× 105 tonsof sugarcane/year), The Ester Mill, average capacity(1:3×106 tons of sugarcane/year) and The Santa ElisaMill, high capacity (6× 106 tons of sugarcane/year).The information needed to apply the method wasobtained from answers to a speciFcally prepared

questionnaire, by visits, interviews and analysis ofthe specialized literature. The Feldwork was carriedout at the mills during 1999.

5. Results

The obtained data was compiled into 11 tables,one for each year, analogous to Table 1, however thecolumns referred to Groups 1, 2 and 3 substituted bythe columns which refer to the mills, with the clas-siFcation obtained for each indicator from each mill.The evolution of the global performance for each mill,obtained from the sum of the points given to the in-dicators during the 11 years, can be seen in Fig. 1from 1987 to 1997. The average global production ofthe mills for the 11 years analyzed is summarized inTable 3 from 1987 to 1997.

100

110

120

130

140

150

160

170

180

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

Years

Sco

re

Sao Jose Ester Sta Elisa

Fig. 1. Evolution of production in the mills. From 1987 to 1997.


Table 3QuantiFcation of environmental performance—average for 1987 to 1997

QuantiFcation of environmental Sao Jose Ester Santaperformance Elisa

Soil utilization(1) Performance of the (a) Growth in area 2 3 3use of soil for (b) Use of the area for sugarcane 2 2 3sugarcane cultivation (c) Agricultural productivity (t/ha) 3 2 3on land (d) Environmental damage to 3 3 3

sugarcane cultivation(e) Environmental recovery 1 1 2(f) Agricultural specialization 1 2 2

(2) Performance of the (a) Dynamics of the activity 2 2 2use of soil for (b) Agricultural productivity (t/ha) 3 2 3sugarcane cultivation (c) Substitution of other food crops 2 2 2in an economic (d) Agricultural specialization (crop 1 2 2environment. rotation or alternation)(3) Performance of the (a) Dynamics of the activity 2 2 2use of soil for (b) Labor employment index per 1 2 2sugarcane cultivation 1000 hectares harvestedin a socialenvironment at anemployment level.Total Use of the soil (C) 23 (B) 25 (B) 29

Chemical(4) Performance of the (a) Toxic level of chemical inputs 3 3 3use of chemical inputs (b) Permanence of chemical input in 3 3 3in the soil, on land the environment (years)

(c) Use of chemical inputs 1 1 2(d) Agricultural productivity (t/ha) 3 2 3

(5) Performance of the (a) Use of chemical inputs 1 1 2use of chemical inputs (b) Agricultural productivity (t/ha) 3 2 3in an economicenvironment.Total Chemical inputs (B) 14 (C) 12 (A) 16

Harvest(6) Performance of the (a) Burnt area 1 1 1sugarcane harvesting (b) Burning practice 1 1 2on land (c) Mitigation of burning practice 1 1 3

based on mechanization index(d) Agricultural productivity (t/ha) 3 2 3

(7) Performance of (a) CO emission by the burning of 1 1 1sugarcane harvesting the sugarcane (t/year)in air resources. (b) Emission of Particulate Material 1 1 1

in the burning of sugarcane (t/year)(c) CH4 emission in the burning of 1 1 1sugarcane (t/year)

(8) Performance the (a) Alcohol loss through the burning 1 1 2sugarcane harvesting of sugarcane (%)in an economical (b) Harvester fuel expenditure (l/t) 1 1 3environment. (c) Harvester productivity 1 1 2

(1000t/harvester)


Table 3 (continued)


(9) Performance of the (a) Number of employees per 1000 1 2 2harvest in a social ha harvestedenvironment (at an (b) Potential for substituting men for 1 2 2employment level) machinesTotal Harvest (C) 14 (C) 15 (C) 23

(10) Performance of (a) Area irrigated with liquor in % 2 2 2the use of liquor on (b) Tendency of irrigation with 2 2 2land liquor in %

(c) Liquor availability tendency in m3 3 2 3(d) Index of liquor application per 1 2 1hectare (m3=ha)(e) Agricultural productivity (t/ha) 3 2 3

(11) Performance of (a) CO emission through the 1 1 3the transport of liquor transport of liquor (t/ha)in air resources. (b) NOx emission through the 1 2 3

transport of liquor (t/ha)(c) SOx emission through the 3 2 3transport of liquor (t/ha)(d) Particulate Material emission 3 2 3through the transport of liquor (t/ha)

(12) Performance of (a) Chemical fertilizer economy (t) 3 3 3the application of (b) Fuel expenditure (l/ha) 1 2 0liquor in an (c) Index of chemical input use 1 1 2economicalenvironment.Total Use of liquor (C) 24 (C) 23 (B) 28

Transport(13) Performance of (a) CO emission (t/t of sugarcane) 3 3 3the transportation of (b) NOx emission (t/t of sugarcane) 3 3 3sugarcane in air (c) SOx emission (t/t of sugarcane) 3 3 3resources. (d) Particulate Material emission (t/t of sugarcane) 3 3 3(14) Performance of (a) Number of trucks for every 1000 2 1 3the transportation of hectares harvestedsugarcane in an (b) Fuel expenditure (l/t of 2 3 3economical sugarcane)environment.Total Sugar cane transport (A) 16 (A) 16 (A) 18

Alcohol(15) Performance of (a) Use of the solid residues in the 3 3 3the industrial Feld (%)processing, on land: (b) Filter cake in (%) applied in the 3 2 3incorporation of the areasolid residues in the (c) Ashes and soot in (%) applied in 3 2 2mill soil. the area

(d) Iodine in (%) applied on the Feld 3 3 3Production (e) Agricultural productivity (t/ha) 3 2 3(16) Performance of (a) Water use (m3=alcohol liter) 3 2 2the industrial (b) Residual water outlet (m3=l) 1 3 3processing in water (c) Disposal of liquid residues in the 3 2 2resources. water streams in (%)


Table 3 (continued)


(17) Performance of (a) CO2 emissions form the juice 3 3 3the industrial fermentation (t/tc)processing in an air (b) CO2 emissions by the burning of 3 3 1resource. bagasse (t/t bagasse)

(c) NOx emissions by the burning of 3 3 3bagasse (t/t bagasse)(d) Particulate Material emissions by 3 3 3the burning of bagasse (t/t bagasse)

(18) Performance of (a) Sugarcane for the production of 2 2 2the industrial alcohol in (%)processing in an (b) Industrial e/ciency (liters 1 2 3economical alcohol/ton sugarcane)environment. (c) EIect of the use of solid 1 1 2

residues in chemical dependency.(d) EIect of the solid residues in 3 2 3agricultural productivity

Total Alcohol production (B) 41 (B) 38 (B) 41

Energy(19) Performance of (a) Energy self-su/ciency in (%) 2 3 3energy production in (b) Electric energy production 1 2 3an economical (kWh/tsc)environment. (c) Electric energy consumption 1 2 1

(kWh/tsc)(d) Sale of electric energy surplus 1 2 2(kWh/tsc)

Total Energy production (C) 5 (B) 9 (B) 9

General total of each mill (C) 137 (C) 138 (B) 164

6. Analysis of the results

The evolution of the production of the mills (Fig.1) shows that all three started oI at diIerent levels,had a signiFcant evolution in the Frst four years ofthe study period and then practically stabilized. It canalso be seen that the Santa Elisa mill operates at abetter and at more constant production level than theothers and comes close to the high production level.The Sao Jose mill presents a lower and more irregularproduction level.

A more detailed analysis of the results taken fromthe 7 constant production activities in Table 2, arepresented below.

7. Use of the soil

Although there had been an increase in agriculturalproduction (tsc/ha), the increase in production was

obtained mainly by the use of more land for cultivationof sugarcane, for all three cases studied. In the SaoJose and Ester mills, the growth of cultivated area wasgreater (above 50% of the initial availability) than thatof the Santa Elisa mill.

During the study period the mills did not carry outthis growth based on the use of natural spaces (forests,river bank vegetation etc.) and it should be notedthat the Santa Eliza mill has increasingly recovered itsriver bank vegetation with the use of a reforestationprogram.

It is usual in Brazilian sugarcane cultivation for80% of the available land to be used for the sugar-cane cultivation, and the other 20% to be used forthe restoration of the sugarcane plantation. In the SaoJose mill, there is no crop rotation, and in the Estermills, the orange plantation as an alternative activityis a decreasing practice, while in the Santa Elisa thereis an increasing alternative activity, represented by the


cultivation of other crops such as soya, peanuts, cornand sweet sorghum. The agricultural productivity ofthe Sao Jose, Ester and Santa Elisa mills averagedaround 81, 75 and 89 tones of sugarcane per hectare(tsc/ha), respectively. Only the Ester mill showed de-creasing tendency in their agricultural e/ciency in-ferior to the Copersucar [8] 80 tsc=ha rate. Thereforeonly Santa Elisa factory presented an average perfor-mance classiFcation (B) for the use of the soil, whilethe other two had a low performance classiFcation (C)(Table 3).

8. Use of chemical inputs

Among the fertilizers and pesticides used forsugarcane cultivation, the chemical products of hightoxicity and/or high level of permanence in the envi-ronment were not declared by the factories. Recently,the great majority of the pesticides are liquid, whichmakes their absorption by the environment quickand their incidence local. The Sao Jose mill had anaverage (B) performance, the Ester mill had a low(C) performance and the Santa Elisa mill had a high(A) performance. The relationship between the pro-ductivity and the utilization of the chemical inputswill be analyzed in another publication.

9. Harvest

It’s a common practice in Brazil to burn the sugarcane Feld to facilitate the harvesting process. Thispractice is responsible for the low environmental per-formance classiFcation achieved by the mills in thisresearch. In the Sao Jose and Ester mills, the burningpractice reaches 100% of the sugarcane Feld. The har-vest in the Sao Jose mill is completely manual, whileat the Ester factory there is an increasing mechaniza-tion process. In the Santa Elisa mill, the harvest of rawsugarcane (not burned) has been increasing, reachingup to 48% of the cultivated area in 1997. Therefore,all three mills, although in diIerent ways, contributesigniFcantly to the emission of gas pollutants and con-sequently to the greenhouse eIect. It is important tonote that the emission of pollutants by the machinesis insigniFcant compared to the emissions from theburning of the sugarcane plantation.

The burning of the sugarcane also presents a neg-ative economic impact, as there is a loss of sucrosethrough the process of exudation caused by the hightemperatures reached during the burning. The losses,due to the burning of sugarcane, are 3%, 4% and 2%out of the total alcohol production in the Sao Jose,Ester and Santa Elisa mills, respectively.

On the other hand, the loss of sucrose also occursduring mechanical harvesting, because the sugarcaneis cut up during the process, causing exudation at theextremities of the pieces. However, information on thevalue of these losses is not available.

The low performances (c) obtained by the factoriesare due to the burning of the sugarcane plantations. Itis also worth noting that the collection of raw sugar-cane (no burning practice) leaves behind a great quan-tity of organic matter (specially leaves), which mustbe incorporated into the soil. This requires specialknowledge and adequate handling in order to avoidthe infestation of insects that can be harmful to sugar-cane plantation, as in the case of the small grasshopper(Aethalion reticulatum).

10. Use of the liquor

It has been observed that the growth of the areafor sugarcane cultivation is greater than the growthof the area irrigated with liquor. The irrigated area atSao Jose mill had a decreasing tendency in relationto the total area harvested, reaching a radius of only5 km. In this way, the liquor application rates corre-spond to an average of 358 m3=ha, far more than the150 m3=ha considered acceptable. The Ester mill pre-sented an increase in the irrigated area in relation tothe collected area and has a radius of 18 km. Underthese conditions, it can apply lower rates, in the orderof 129 m3=ha. Even though in the Santa Elisa millthere is an increasing irrigated area, reaching a radiusof 25 km (recently reduced to 17), the 300 m3=haapplied index is also superior to the 150 m3=harecommended.

The average for the irrigated area in the three caseswas somewhere between 20% and 35% of the totalarea, reaching almost 50% at Santa Elisa. All threemills reached average qualiFcation for the area irri-gated with liquor (Table 3). Despite the fact that theapplication of liquor in the soil reduces theoretically


the use of fertilizers (Table 3, item 12a), there hasbeen an increasing use of chemical fertilizers in theSao Jose and Ester mills. Santa Elisa mill showeda decrease in the use of these products. The limitedrange of the area irrigated with liquor in relation tothe non-irrigated area can be the cause of the irregu-larity between theoretical economy and the eIectivechemical product use.

The emission of atmospheric pollutants, due to theuse of diesel fuel trucks for the distribution of theliquor, is small when compared to the beneFts ob-tained by the application of the product, but the envi-ronmental e/ciency of this activity diIers from onesugar mill to another. It is important to remember thatthe main environmental concerns due to the use of theliquor on the soil are linked to the inFltration and con-tamination of underground waters and with the evap-oration of the polluting elements. These topics havenot been dealt with in this research.

As shown in Table 3, the ClassiFcation of environ-mental performance of the sugar mills for this activitywas low (C) for the Sao Jose and Ester sugar mills,and average (B) for the Santa Elisa sugar mill.

11. Sugarcane transportation

Fuel consumption for the transport of sugarcane wasless than 0.7 liters of diesel for each ton of sugar canetransported. The amount of trucks used depends ontheir transport capacity. Special trucks, for sugar canetransport, which have a great cargo capacity to carrythree times the normal amount per trip, were used.The amount of pollutants emitted was less than 0.5tons for each ton of sugar cane transported. The threemills had high (A) performance for this activity.

12. The production of alcohol

Taking as a reference the 84.5 liters per ton ofmilled sugarcane from Copersucar [8], it can be seenthat the Sao Jose mill, with an average of 76 liters perton of sugarcane is far from the technological situa-tion of other industrial installations in the state of SaoPaulo. This is not the case with the Ester and SantaElisa mills, where both reach an average of 86 liters ofalcohol per ton of sugarcane.

Based on Table 3, all the mills reached an average(B) level of production in industrial activity. This re-sult is very much related to industrial waste manage-ment.

The production of alcohol (sugar-alcoholic activityin general) is based on the production of large amountsof solid, liquid and gaseous residues. Therefore thehandling of these residues is added to the evaluationof industrial activity.

13. Handling of solid residues

The solid residues are Flter cake, ash from burningthe bagasse, soot from the boilers, and sludge from thetreatment systems. In all three sugar mills analyzed,all the solid residues were incorporated into the soil(15a, 15b, 15c, 15d indicators in Table 3), which couldhelp improve the quality of the soil and consequentlyincrease agricultural production.

The incorporation of the solid residues into the soil,together with the application of the liquor, has not re-duced the amount of chemical fertilizers used in boththe Sao Jose and Ester mills. Just one, the Santa Elisasugar mill had a reduction in the use of chemicalfertilizers. The evaluation of 18c and 18d indicators(Table 3) not only shows the low impact of this activ-ity in the reduction in the amount of chemical productsused but also the low agricultural yields in the case ofthe Ester mill.

14. Handling of liquid residues

The liquid residues during the industrial phase ofthe production of alcohol are: liquor, sugar cane wash-ing water, water from the condensers and from thecleaning of the equipment, apart from other residualwater. The liquor was treated separately due to it be-ing practically solely from sugar cane juice milling.This extract is extremely polluting as it contains ap-proximately 5% organic material and fertilizers suchas potassium, phosphorus and nitrogen.

Water has various uses in the industrial process,and it is most used for the sugar cane washing beforethe milling. (There are already techniques to elimi-nate this practice, which however are little used). Theamount of water used in an industrial process is large


generating a high level of liquid residues. A good ideais to use this water in a closed re-circulation and Fltersystem circuit. The demand for water observed at themills was 3 m3=la (liters of alcohol produced) in theSao Jose mill, 9 m3=la at the Ester mill and 8 m3=la atthe Santa Elisa mill. However, the elimination of theresidual waters is between 0.5 and 1:0 m3=la for theSao Jose mill and 0:03 m3=la for the Ester and SantaElisa mills.

The great diIerence in elimination occurs becausein the Sao Jose mill only a fraction of the residualwater is recycled, while in the Ester and Santa Elisamills this recirculation is around 95% to 96% of thevolume of residual water.

In the Sao Jose and Santa Elisa mills all the resid-ual water returns to the soil, however in the Estermill approximately 30% goes into a cooling lake andafterwards to the water streams (water from the evap-orators and cooling of the distilling systems).

15. Handling of gas emissions

The emission of CO2 is not considered a pollutingemission as it is absorbed in the growth cycle of sug-arcane. The quantities of the other gas emissions perliter of alcohol produced are insigniFcant. The Partic-ulate Material (PM), emitted during the burning of thebagasse, is basically made up of soot and ash. Soot,which is practically pure carbon, is a problem whenthe mills are located near the cities, which makes itscontrol a must. In the three cases studied, the Par-ticulate Material was removed by a gas washer andincorporated into the soil.

16. Production of energy

The energy obtained by the burning of sugar canebagasse in the mill itself provided self-su/ciency, interms of energy, for the three cases studied. Apart frombeing economically important, it was also importantin terms of environment as it avoided the emission ofCO2 from fossil fuel.

The indexes suggested by Copersucar [8] forthis activity were adopted, which are as follows:97% energy su/ciency, 15:62 kWh=tsc electric en-ergy, 11:76 kWh=tsc consumption and the sale of

0:31 kWh=tsc The Sao Jose mill, presented lowenvironmental (C) production at 5 points, as its pro-duction of energy is only to satisfy internal demand.The Ester and Santa Elisa mills presented averageproduction (B), both with 9 points each (Table 3).

17. Conclusion

The methodology used, provided a vision of envi-ronmental e/ciency for the three mills studied. As theconcept of environmental e/ciency was representedon a numerical scale, it allowed comparisons, in termsof performance, to be made between the mills, theiractivities and between indicators from mill to mill. Itssystematic use allows the evaluation of not only theglobal tendency but also the tendency for each activityand for each one of the indicators. Thus, it can be seenas a management instrument, which apart from point-ing out those activities in more need of attention, setsup objectives and evaluates the consequences from theactions implemented.

Taking as a basis the cases studied; there are someresults that seem paradoxical. For example, the appli-cation of the liquor and the incorporation of the solidresidues in the soil provided economy in fertilizersfor the three mills. However, only one of them (theSanta Elisa mill) showed a tendency to reduce the useof chemical fertilizers. In the other two the oppositeoccurred. There is also no clear relationship betweenthese facts and the productivity of each mill. This in-dicates that if the data is correct, it will be necessaryto establish other connections and check the inRuenceof the variables that were not considered such as: soilcomponents and rain distribution.

Although the development of this methodology wasmotivated by the necessity to evaluate the productionof alcohol as a fuel in Brazil, it can be easily adaptedfor the evaluation of any agricultural-industrial activ-ity.

The method can be improved in terms of deFningdiIerent weights for the indicators, as some may inRu-ence more than others. The deFnition of the indicatorsin Groups 1, 2 and 3 was based on the authors’ deF-nitions and sensibility, however this can be discussedmore deeply to try and identify the best practices andadopt them as references.


References

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[2] Daly, HE. Policies for sustainable development. Herman E.Daly, University of Maryland, College Park, MD 20742,USA. Collection of papers for discussion in the courseHS-053 Demography and Human Ecology (in Portuguese),by Professor Daniel Joseph Hogan, Institute of Philosophyand Human Sciences/State University of Campinas—Brazil,1996.

[3] Cavalcanti C. Nature and development: study for a sustainablesociety (in Portuguese). C. Cavalcanti (Org). Sao Paulo:Cortez, Recife, PE: FundaScao Joaquin Nabuco, 1995.

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[6] Borrero, M.A. ValdUes, An environmental management methodfor sugar cane alcohol production in Brazil and the conceptof environmental e/ciency. Ph.D. Dissertation, Faculty ofMechanical Engineering, State University of Campinas, 2000.187p (in Portuguese).

[7] Copersucar. Internal paper 10 de Julho de 1977. By requestingof Dr. Electo Silva Lora, 1977a (in Portuguese).

[8] Copersucar. An inventory of CO2 emission due to productionand use of sugar cane, sugar and alcohol in Brazil(in Portuguese)—a report prepared by Copersucar Centreof Technology for the Brazilian government for theintergovernmental panel on climate change (IPCC)—In:http://www.mct.gov.br/gabin, 1997.

http://www.mct.gov.br/gabin

an environmental management method for sugar cane alcohol production in brazil

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