


































Energy and Earth Science 
Vol. 3, No. 2, 2020 

www.scholink.org/ojs/index.php/ees 

ISSN 2578-1359 (Print)   ISSN 2578-1367 (Online) 

11 
 

Original Paper 

Waste-Energy: Feasibility Study of Watermelon (Endocarp) 

Waste as Raw-Material for Bio-Fuel Prodution 

Biose Osadebe
1*

, Imhontu U. Maureen
1
, Akenzua Oghosa

1
, Ehigiamusoe Osaro

1
, Okorie Christopher

1
, 

Atsegha Bildad
1
, Onabe James

1
, Angalapu

 
Daudeigha Jonah

1
 & Igbinomwanhia Iyeke

2
 

1
 Environmental Pollution and Remediation Unit, National Centre for Energy and Environment, Energy 

Commission of Nigeria, Benin City, Edo State, Nigeria 

2
 Department of Mechanical Engineering, Faculty of Engineering, University of Benin, Benin City, Edo 

State, Nigeria 

*
 Biose, Osadebe, E-mail: bosadebe@yahoo.com 

 

Received: April 30, 2020         Accepted: May 15, 2020        Online Published: July 16, 2020 

doi:10.22158/ees.v3n2p11               URL: http://dx.doi.org/10.22158/ees.v3n2p11 

 

Abstract 

Waste to energy plays an important role in fulfilling the world’s future demands. The continuous 

climatic change which is primarily caused by the atmospheric concentration of greenhouse gases from 

the continuous use of fossil fuel due to high demand of energy in our society has affected the human 

race negatively over the years. Similarly, the improper disposal of agricultural waste (watermelon 

waste) in markets and environs creates pungent smell overtime and attracts harmful organisms in our 

environment, destroying the aesthetics of the market, therefore, making it environmentally unsafe for 

man. This paper therefore describes how feasible it is to produce bio-ethanol from agricultural waste 

with a focus on water melon. The waste was gotten from the market and processed to get the endocarp 

after which a locally fabricated juicing machine was utilized for extraction of the juice from the 

endocarp of watermelon waste. The fermentation pot housed 60 litres of juice for 5 days and 

laboratory test analysis was carried out during the period of fermentation, this was to monitor the 

progression of fermentation. The distillate produced 65.25% alcohol content with a volume of 19.5 

litres. The utilization of watermelon waste for bio-ethanol production if exploited will lead to 

environmental sustainability, energy efficiency and waste to wealth. 

Keywords 

waste to energy, fossil fuel, water melon waste and bio-ethanol 

 

 



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1. Introduction 

Nowadays, the high demand for energy has become a thing of concern globally (Prasad et al., 2017), and 

this is because of the dependence on petroleum-based fossil fuel which is exhausting and depleting very 

fast in the cause of meeting its continuously increasing demands (Hossain et al., 2014). Moreover, it has 

been realized that Fossil energy causes greenhouse gas emissions that have negative effects on the 

environment. The enormous accumulation of Carbon dioxide (CO2) in the environment is directly 

responsible for global warming (Naik et al., 2010). Aside the negative effect of CO2 on the environment 

and high demand for energy, there has also been issues concerning waste management. Waste is simply 

any object whose owner does not want to take responsibility for it (Palmer, 1992). Waste management is 

the application of techniques to ensure an orderly execution of the various functions of collection, 

transportation, processing, treatment and disposal (www.sciencedirect.com, 2019). Improper disposal of 

waste causes environmental pollution. This does not affect only the atmosphere but also the populace in 

that environment by exposing them to health challenges like Dysentery, Diarrhea and Respiratory 

diseases etc. (Rinkesh, 2020). The advocacy for waste to be converted to a useful resource is necessary in 

Nigeria. Bio-ethanol derived from waste, which is our focus in this study, is a renewable and 

environmentally friendly type of fuel produced from a renewable and sustainable energy source called 

Biomass (Mabee et al., 2005). Biomass is the material derived from plants that use sunlight to grow 

which include plant and animal material such as wood from forests, material left over from agricultural 

and forestry processes, organic industrial wastes, human wastes and animal wastes (Salman, 2019). 

Bio-ethanol’s impressive characteristics such as flame speed and wide range of flammability, high octane 

number (108) and evaporation enthalpy gives it a higher Compression Ratio (CR) with a shorter burning. 

Besides, Bio-ethanol can be used as transportation fuel in various feasible ways, directly or blend with 

gasoline called “gasohol” (Balat, 2007). In the United States of America, the most common blended 

Bio-ethanol used is E-10 containing 10% of ethanol concentration and 90% gasoline (Balat, M. & Balat, 

H., 2009). This research study is designed not just to solve the challenges of energy demand but to also 

reduce/eliminate completely the ugly sites of watermelon wastes in our environment (farms, markets and 

residential) which will bring about a sustainable environment for all. 

 

2. Materials and Methodology 

2.1 Area of Study 

The study area is Tenboga Market square. It is located along the upper mission road in Benin City of 

Edo State Nigeria.  

2.2 Feedstock Collection 

Watermelon waste was collected from tenboga market located at upper mission Road, Benin City of 

Edo State Nigeria. Personal Protective Equipments (PPE) were employed during field work. It was 

recorded that 62 balls of water melon waste was collected which weighed 205kg.  

 



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Figure 1. Heap of Water Melon Waste 

 

2.3 Sample Preparation 

A knife was used to collect the endocarp of the watermelon waste which weighed 108kg and a locally 

fabricated juicing machine was used to extract juice from the endocarp of the watermelon waste. A 

cloth sieve was used to further remove the chaff from the juice and a volume of 105 litres of juice was 

obtained. 

 

 

Figure 2. Collection of Endocarp 



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Figure 3. Extracted Juice from Endocarp 

 

2.4 Fermentation Process 

Fermentation is an important characteristic of alcohol production. In this regard, the prepared water 

melon juice was fed into the tightly covered fermentation pot to ensure anaerobic digestion of the 

feedstock. The fermentation pot had a stirrer which helps for proper stirring of the feedstock to enable 

enzymes act equally on the feedstock. Brewer’s yeast of 17g was added to 105 liters of the water melon 

juice. Physicochemical analysis (pH, conductivity, sugar content, refractive index, and alcoholic 

content) of the feedstock was recorded during the fermentation process.  

2.5 Alcohol Distillate 

The bio-ethanol plant which was fabricated by the Environmental Pollution and Remediation Unit of 

the National Centre for Energy and Environment as presented in Figure 4 was utilized for the 

distillation of ethanol from watermelon endocarp waste. Laboratory test of the distillate was also 

carried out and recorded this was to ascertain the alcoholic content of the feedstock. 

 

 

 

Figure 4. Bioethanol Plant 

Distillation Unit/Condenser 

Fermentation Pot 

Water Drum 

Boiler 

Digital Temperature probe 

Tyres for mobility 

 

Ethanol collection Pot 



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The result of analysis and graphical representation of the beer (fermenting feedstock) and distillate 

respectively are presented below. 

 

3. Results and Discussion 

3.1 Results 

 

Table 1. Physicochemical Analysis of Beer 

Period pH Conductivity Sugar Content Refractive Index Alcoholic Content 

Day 0 5.30 26.00 8.00 36.00 BDL 

Day 1 3.70 34.00 8.00 34.00 BDL 

Day 2 3.30 42.00 6.40 28.00 BDL 

Day 3 3.20 43.00 5.80 26.00 BDL 

Day 4 3.10 44.00 5.20 24.00 BDL 

Note. BDL: Below Detectable Limit. 

 

Table 2. Laboratory Test of Alcohol Content of Each Distillate 

Distillate pH Conductivity Sugar Content Refractive Index Alcoholic Content 

1
st
DISTILLATE 4.70 0.00 

 

20.40 

 

86.00 

 

59.00 

2
nd

DISTILLATE  4.70 

 

0.00 

 

22.60 

 

96.00 

 

58.00 

 

3
rd

DISTILLATE 5.00 

 

0.00 

 

23.60 

 

100.00 

 

56.00 

 

4
th

DISTILLATE 4.80 

 

0.00 

 

23.20 

 

98.00 

 

56.00 

Average Values 4.80 0.00 22.45 95.00 57.25 

 

 



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Figure 5. Graphical Representation of the Relationship between PH and Days of Fermentation 

 

 

Figure. 6. Graphical Representation of the Relationship between Conductivity and Days of 

Fermentation 

 

 

Figure 7. Graphical Representation of the Relationship between Sugar Content and the 

Fermentation Days 

 

 



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Figure 8. Graphical Representation of the Relationship between Refractive Index and the 

Fermentation Days 

 

3.2 Discussion 

Table 1 represents the fermentation analysis of the feedstock. The PH of the sample decreased from 

5.30 to 3.10 (Increasing acidity) from day 0 to day 4. 

Similarly, the sugar content and refractive index of the fermenting feedstock decreases from 8.00 to 

5.20 and 36.00 to 24.00 respectively from day 0 to day 4 except for the sugar content for day 1 which 

remained unchanged.  

The conductivity of the fermenting feedstock was observed to increase from 26.00 to 44.00. 

The inverse relationship between the fermentation days of pH, sugar content and refractive index and 

the direct relationship between fermentation days and conductivity certified the formation of alcohol. 

Figures 1-4 clearly represents this direct and inverse relationship between physiochemical parameters 

and fermentation days. 

It was also observed that table 2 represents the analysis of the distillate (ethanol). It revealed the 

average pH of 4.80, sugar content of 22.45, refractive index of 95.00 and alcoholic content of 65.25% 

of the yield. This therefore implies that water melon waste is a feasible raw material for ethanol 

production and if exploited will compliment the energy needs of man and bring about a sustainable 

environment. 

 

4. Conclusion 

The production of Bio-ethanol from water melon waste using a localized Bio-ethanol plant was 

successful. The sugar content and alcoholic content of the end product was measured 22.45 % Brix and 

65.25% respectively. The Environmental Pollution and Remediation Unit, National Centre for Energy 

and Environment during their recognizance visit to farms and markets in Benin City observed that a lot 

of agricultural waste materials are generated on a daily basis which destroys the aesthetics of our 

markets block drainages and also affect man. This wastes which can be a useful resource if employed 



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will help clean up our environment and also provide clean energy for all. 

 

Acknowledgement 

We thank the National Centre for Energy and Environment, Energy Commission of Nigeria for the 

financial support towards the completion of this project. 

 

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