THE WATER FOOTPRINT ASSESSMENT OF ETHANOL FROM CASSAVA IN
LOPBURI PROVINCE OF THAILAND
Anattaya Boonhuad1 1, *, Nathsuda Pumijumnog 2 #, Achara Ussawarujikulchai 3 #
1
Affiliation of 1 st
author , M.Sc. Technology of Environmental Management, Faculty of Environment and
Resources, Mahidol University, Thailand.
2
Affiliation of 2 nd
author, Faculty of Environment and Resources, Mahidol University, Thailand.
*e-mail: anattaya_b@hotmail.com, #e-mail: nathsuda.pum@mahidol.ac.th, achara.uss@mahidol.ac.th
Abstract
The objective of this study is to assess water footprint of ethanol from cassava based in Lopburi Province of Thailand. The results of green and grey water footprint from cassava crop are 333.63, and 97.56 m
3
/ton. Total water footprint of cassava crop is 431.19 m
3
/ton. Compared green and grey cassava crop water footprints with a liter of ethanol are
1,962.53 and 558.18 liter water/liter ethanol. While the blue water footprint is not represent in
Lopburi cassava crop. The result of blue water footprint taken from ethanol production process is 11.41 liter water/liter ethanol. While the result of ethanol production process is not represent in term of green and grey water footprint because of the factory do not intake green water to be raw material and wastewater from factory are discharged to farm tree field therefore the grey water is not represent. The result of water footprint of ethanol based cassava in term of green, blue and grey water footprint are 1,962.53, 11.41 and 558.18 liter water/liter ethanol, respectively. Compared size of water footprint in this study, the green water footprint had the biggest size due to a lot of effective rainfall, followed by grey water footprint and blue water footprint, respectively. The green water footprint in this study taken from crop water use divided with crop yield consequently the green water footprint are advantage from climate data, cassava species, crop methodology and fertilization application rate. The grey water footprint of cassava crop in this study taken from nitrogen application rate to the field per area therefore the volume of grey water are variation with nitrogen application rate.
Keywords: WATER FOOTPRINT/ CASSAVA/ ETHANOL/ CROPWAT MODEL VER. 8.0
Introduction
Water is the most important resource for life, water use can be addressed not only use direct but usually use indirect from everything that consumption such as food, fiber, energy and at all use to produce the products. Water used talking with agricultures, industrials, and domestic activities. Water use consideration in term of green, blue and grey water that socalled “water footprint”. Therefore environmental aspect come from use of natural resources and emitted pollution to environmental, the major polluter is carbon dioxide:CO2 that emitted from use of fossil fuel. Alternatively, the alternative fuel is heavily consideration to promote for replace or decrease use of fossil fuel. The one of alternative fuel’s target is ethanol, which produced from crops such as sugar and starch crops. Thailand consumption fossil fuel in transportation sector statistics is show growing in every year and the volume of bio-energy in term of gasohol used year 2009 was 60% of all gasoline consumption by increasing from 9.2 million liter a day (2008) to 12.2 million liter a day (2009) or increasing 32.2% from 2008.
Year 2009 consumed of gasohol 95 was 8.1 million liter a day increasing 25.5% [1]. Ethanol addressed in 15 year Thailand renewable energy strategic plan in year (2008-2022), develop and implementation this strategy by Department of Alternative Energy Development and
Efficiency (DEDE) called “the 15 year Ethanol development plan” which set target for

promotion product and use of ethanol more than 9 million liter a day for decreasing the oil dependency [2].
Ethanol is significant material to produce gasohol by mixed with pure gasoline. In
Thailand the key crops for ethanol production are sugar can and cassava and this research mention in cassava. The expected for cassava production for ethanol, is 2.27 million tons to more than 15 million tons within 2022 [2]. Ultimately, crops for cassava require the resources such as land, nutrients, sun light and especially fresh water to growth. Otherwise, cassava is food crops and Thailand is the first export cassava in the word (2006-2010) by 6 million tons per year, 2010 cassava production is 22 million ton [3]
Water is link to almost ethanol stream, beginning from cassava crops production, fermentation process, and pollution management. Cassava production in Thailand use water from precipitation that so-called green water and emitted wastewater to natural sink that socalled grey water. The fermentation process use water from surfaces water and groundwater that so-called blue water and emitted wastewater to natural. For this research shall account and define the water footprint of ethanol production from cassava per volume of water consumption (cubic meter: m 3 ) including direct and indirect water use for consideration to develop the sustainability gasohol production from crops and support national water management.
According to cassava is the one of raw material for produce ethanol in "the 15 year
Ethanol development plan" The Government exits policy to support the plan by promote the
24 cassava ethanol plant by capacity 5 million liter per day. Sapthip Co.,Ltd is the one of 24 ethanol plant located on 49 Moo 6 Suranarai Road, Nikomlamnarai, Chaibadan, Lopburi capacity is 200,000 liter per day. The raw materials of ethanol plant is very flexible which fresh cassava root, chips, pellets and strach and all species of cassava that planting in
Thailand can be raw material. Lopburi province is the 7th cassava promotes production zoning because of potential of soil properties, low competitive, nearby cassava ethanol plant in area [4].
Methodology
This study consideration the water footprint of ethanol produced from cassava by only one cycle of the process. The area of this study is Lopburi province, Thailand based on the methodology described by [5]. The water footprint assessment are divided in to 3 parts; cassava crop, ethanol production and ethanol based from cassava. The green and blue water footprint of cassava crop can be calculated from CROPWAT model version 8 for find down the crop water use (CWU, m3/rai), data output from CROPWAT is crop evapotranspiration
(ETo, m3/rai). Data input to CROPWAT model are the climate data from Lopburi meteorological station, crop parameters are obtained from [6]. Soil data can use from [7].
Data on the average harvest area and yield of cassava (ton/ha) were from questionnaires that the researcher collected. Crop water use can calculate by total of accumulation of daily evapotranspiration of green and blue water footprint (m 3 /ton) calculated by crop water use divided by crop yield (Y, ton/rai), (Equation 1).
WF green
= CWU green/blue
Y
(1)
Grey water footprint of cassava crop is calculated based on nitrogen application rate
(AR, kg/rai) to the field per area times the leaching-run-off fraction (α) in this study is Pasak and Lopburi river, divided by the maximum acceptable concentration (Cmax, kg/m
3
) minus the natural concentration for the pollutant considered (Cnat, kg/m
3
) and the divided by the crop yield (Y, ton/rai), (Equation 2)

WFgrey = (α x AR)/(Cmax-Cnat)
Y
(2)
The water footprint of ethanol production process calculated by “the chainsummation” method, where is can be applied for the production system produce one type of product output. The green and blue water footprint of ethanol production process can calculated by total green/blue water use (WF green/blue(s) , liter water) divided by production yield (P, liter ethanol), (Equation 3)
=
∑
WF green/blue (s)
(3)
1
P
The grey water footprint from product is calculated based on pollutant load (L, kg) divided by the maximum acceptable concentration (Cmax, kg/m
3
) minus the natural concentration for the pollutant considered (Cnat, kg/m
3
), (Equation 4)
WF grey = L
Cmax-Cnat
(4)
The water footprint of ethanol production process that produces from cassava can be calculated as equation 5.
WF ethanol
= WF ethanol
(c) + WF ethanol
(p) (litres water/ litres ethanol) (5)
Results
The results of water footprint assessment are divided in to 3 parts; 1) the water footprint of cassava crop, 2) the water footprint of ethanol production process and 3) the water footprint of ethanol. The result of 3 parts represented in term of green, blue and grey water footprint. For the part of cassava crop is shown in table 1. The green water footprint is
333.63 m
3
/ton and grey water footprint is 97.56 m
3
/ton. Total water footprint is 431.19 m
3
/ton. Blue water footprint of cassava crop in Lopburi is not represented because cassava crop use only precipitation for cassava growth.
Table 1.
Water footprint of cassava crop in Lopburi province water footprint of cassava crop, Lopburi province (m 3 /ton)
Green water footprint Blue water footprint Grey water footprint Water footprint
333.63 - 97.56 431.19
The result of water footprint of ethanol production process is shown in table 2. Blue water footprint is 11.41 liter water/liter ethanol, in this study found the ethanol production process consumption raw water from Pasak river and zero discharged wastewater to natural area.

Table 2.
Water footprint of ethanol production process water footprint of ethanol production process (liter water/liter ethanol)
Green water footprint Blue water footprint Grey water footprint Water footprint
- 11.41 - 11.41
Consequently, the result of water footprint of ethanol for cassava-based, specific one liter of ethanol is shown in table 3, Green water footprint is 1,962.53 liter, blue water footprint is 11.41 liter and grey water footprint is 558.18 liter. Therefore, total water footprint of this study is 2,532.21 liter.
Table 3.
Water footprint of ethanol based cassava water footprint of ethanol production process (liter water/liter ethanol)
Green water footprint Blue water footprint Grey water footprint Water footprint
1,962.53 11.41 558.18 2,532.12
Discussion and Conclusion
The result in this study, the total amount of the green, blue and grey water footprint of ethanol based cassava in Lopburi Province is 2,532.12 m
3
/ton. Water footprint of cassava crop is assumed from crop water use, there are no water limitations to crop growth and nitrogen application rate to the crop. Water footprint of ethanol production is assumed from summation of water use in the ethanol production process included water use for production, boiler and others water supply. The result from cassava crop are shown in term of green and grey water footprint because of the blue water footprint is not represent in Lopburi cassava crop. The result of ethanol production process is represent in term of blue water footprint because of the factory do not intake precipitation to be raw material and wastewater from factory are collected to be treat by anaerobic process that produced biogas and water discharge to eucalyptus field. According to comparison size of water footprint in this research, the green water footprint had the biggest size due to a lot of effective rainfall, followed by grey water footprint and blue water footprint, respectively. The green water footprint in this research taken from crop water use divided with crop yield. Crop yield are result from crop production divided by crop area therefore the crop yield and green water footprint are advantage from climate data, cassava species, crop methodology and fertilization application rate. The grey water footprint of cassava crop in this research taken from nitrogen application rate to the field per area by calculating leaching run off fraction of
10% nitrogen apply to the crop field therefore the volume of grey water are variation with nitrogen application rate. Cause of grey water footprint of ethanol production process was not represented because the 100 percent of wastewater from process will be collected to treat at anaerobic pond and discharged to eucalyptus field near by factory 500 meter that mean the zero discharge. The blue water footprint from this research taken from ethanol production process, the factory intake raw water from Pasak river to collected in the raw water pond and treat by water treatment process before conducted to use in the process. The reduce volume of water footprint shall conducted key parameter but not limit to; crop area, cassava species, crop methodology, soil properties and fertilization apply rate to be consideration.

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กรมพัฒนาที่ดิน .
การศึกษาปริมาณความชื้นในดินเพื่อปลูกพืชไร่และไม้ผลบางชนิดโดยใช้ซอร์ฟแวร์
CROPWAT
ที่อ าเภอชัยบาดาลจังหวัดลพบุรี .
กระทรวงเกษตรและสหกรณ์ .
สืบค้นข้อมูลจาก http://oss101.ldd.go.th/web_research/_doc_research/water/01cropwat%20for%20lopburi.pdf [
วันที่เข้าถึง 12
เมษายน 2554]