Advances in Phytochemistry, Textile and Renewable Energy Research for
Industrial Growth – Nzila et al. (Eds)
© 2022 Copyright the Author(s), ISBN: 978-1-032-11871-0
Open Access: www.taylorfrancis.com, CC BY-NC-ND 4.0 license
Evaluation of sugarcane vinasse and maize stalks for anaerobic digestion
Mohamed Kibet Kiplagat, Cleophas Achisa Mecha & Zachary Otara Siagi
Department of Mechanical & Production Engineering, Moi University, Eldoret, Kenya
ABSTRACT: Sugar cane vinasse and maize stalks waste disposal poses serious challenges to the environment.
However, anaerobic digestion is an attractive treatment method for these wastes. The current study therefore
established the suitability of theses wastes for anaerobic digestion. Specifically, the study aimed at characterizing the substrates and anaerobic digestion of the substrates. The raw materials were collected from Muhoroni
Sugar Company and Uasin-Gishu county maize farms, respectively. The pH, moisture content, chemical oxygen
demand (COD), total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), total organic carbon
(TOC), nitrogen content, and CN ratio were determined based on standard methods. Experiment setups were run
depending on batch experiment. The study established that the pH, moisture content, COD,TS, TSS, TDS, TOC,
and nitrogen content for vinasse were 4.34, 93.91%, 71.28g/L, 7.05%, 6.04%, 1.01%, 2.23 g/L, and 0.27g/L,
respectively. For the maize stalks, the pH, moisture content, TS, TSS, TDS, TOC, and nitrogen content were
7.52, 9.52%, 91.50%, 90.12%, 7.38%, 49.51g/kg, and 1.28g/kg, respectively. The cumulative biogas yield for
sugarcane vinasse and maize stalks were 329mL and 385 mL, respectively. In conclusion, this study found that
the characteristics of vinasse and maize stalks are suitable for biogas production.
1 INTRODUCTION
High oil prices, increasing population, industrialization, and the decline in energy security have all led to an
increase in global interest in biofuels. However, studies
on biomass availability have concluded that by 2050,
the possible contribution of biomass to global energy
supply could vary from 100 EJ/year to 400 EJ/year,
which represents 21%–85% of the world‘s current total
energy consumption, estimated at 470 EJ.Although
biofuels are only a fraction of total biomass, biofuels still have the potential to play a significant role
in meeting future global energy demand, if developed through the appropriate channels (Bailis et al.
2015).
Furthermore, the disposal of some biomass waste
has proved to be a problem in developing countries.
The disposal of vinasse and maize stalks in Kenya
poses serious challenges to the environment. Iqbal
(2016) stated that vinasse has a dark colour, the concentration of total solid and COD value are very high,
and the pH condition of vinasse is 3.25-4.97, while
the total solid (TS) value in vinasse is 63,000–79,000
mg/L. If vinasse is discharged directly into the rivers
without treatment, water biota will be killed. Dissolved
oxygen in the rivers is used by oxidation bacteria to
degrade COD and BOD, hence the availability of dissolved oxygen is depleted, so the water biota cannot
∗ Corresponding author
breath and finally die (Summardiono et al. 2013).
The same applies for maize stalks. Here in UasinGishu county maize stalks are abundant since they are
left in the farms and even sometimes burned. These
disposal methods of maize stalks cause harm to the
environment.
Attempts have been made to establish ways to dispose of vinasse with minimum negative effect on
the environment. Iqbal (2016) in his review further
supported and concluded that it is more effective to
degrade organic materials through anaerobic digestion than aerobic treatment. He further stated that
anaerobic digestion is a viable option for sugarcane
vinasse processing and enables energy recovery as
biogas production.Studies have established that maize
stalks could be used as a raw material for anaerobic fermentation (Adebayo et al. 2014; Bruni 2010; Zhong et
al. 2011). A pretreatment process is required to decompose cellulose to reduce the volume of material and
increase production of biogas (Antognoni et al. 2013).
Based on these facts and problems associated with
disposal of these wastes, this study evaluated the
potential of these wastes (vinasse and maize stalks) as
substrates for co-digestion. Co-digestion is the simultaneous digestion of a homogenous mixture of two
or more substrates. The most common situation is
when a major amount of a main basic substrate (such
as manure or sewage sludge) is mixed and digested
together with minor amounts of a single, or a variety
of additional substrates.
296
DOI 10.1201/9781003221968-39
Industrial Growth – Nzila et al. (Eds)
© 2022 Copyright the Author(s), ISBN: 978-1-032-11871-0
Open Access: www.taylorfrancis.com, CC BY-NC-ND 4.0 license
Evaluation of sugarcane vinasse and maize stalks for anaerobic digestion
Mohamed Kibet Kiplagat, Cleophas Achisa Mecha & Zachary Otara Siagi
Department of Mechanical & Production Engineering, Moi University, Eldoret, Kenya
ABSTRACT: Sugar cane vinasse and maize stalks waste disposal poses serious challenges to the environment.
However, anaerobic digestion is an attractive treatment method for these wastes. The current study therefore
established the suitability of theses wastes for anaerobic digestion. Specifically, the study aimed at characterizing the substrates and anaerobic digestion of the substrates. The raw materials were collected from Muhoroni
Sugar Company and Uasin-Gishu county maize farms, respectively. The pH, moisture content, chemical oxygen
demand (COD), total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), total organic carbon
(TOC), nitrogen content, and CN ratio were determined based on standard methods. Experiment setups were run
depending on batch experiment. The study established that the pH, moisture content, COD,TS, TSS, TDS, TOC,
and nitrogen content for vinasse were 4.34, 93.91%, 71.28g/L, 7.05%, 6.04%, 1.01%, 2.23 g/L, and 0.27g/L,
respectively. For the maize stalks, the pH, moisture content, TS, TSS, TDS, TOC, and nitrogen content were
7.52, 9.52%, 91.50%, 90.12%, 7.38%, 49.51g/kg, and 1.28g/kg, respectively. The cumulative biogas yield for
sugarcane vinasse and maize stalks were 329mL and 385 mL, respectively. In conclusion, this study found that
the characteristics of vinasse and maize stalks are suitable for biogas production.
1 INTRODUCTION
High oil prices, increasing population, industrialization, and the decline in energy security have all led to an
increase in global interest in biofuels. However, studies
on biomass availability have concluded that by 2050,
the possible contribution of biomass to global energy
supply could vary from 100 EJ/year to 400 EJ/year,
which represents 21%–85% of the world‘s current total
energy consumption, estimated at 470 EJ.Although
biofuels are only a fraction of total biomass, biofuels still have the potential to play a significant role
in meeting future global energy demand, if developed through the appropriate channels (Bailis et al.
2015).
Furthermore, the disposal of some biomass waste
has proved to be a problem in developing countries.
The disposal of vinasse and maize stalks in Kenya
poses serious challenges to the environment. Iqbal
(2016) stated that vinasse has a dark colour, the concentration of total solid and COD value are very high,
and the pH condition of vinasse is 3.25-4.97, while
the total solid (TS) value in vinasse is 63,000–79,000
mg/L. If vinasse is discharged directly into the rivers
without treatment, water biota will be killed. Dissolved
oxygen in the rivers is used by oxidation bacteria to
degrade COD and BOD, hence the availability of dissolved oxygen is depleted, so the water biota cannot
∗ Corresponding author
breath and finally die (Summardiono et al. 2013).
The same applies for maize stalks. Here in UasinGishu county maize stalks are abundant since they are
left in the farms and even sometimes burned. These
disposal methods of maize stalks cause harm to the
environment.
Attempts have been made to establish ways to dispose of vinasse with minimum negative effect on
the environment. Iqbal (2016) in his review further
supported and concluded that it is more effective to
degrade organic materials through anaerobic digestion than aerobic treatment. He further stated that
anaerobic digestion is a viable option for sugarcane
vinasse processing and enables energy recovery as
biogas production.Studies have established that maize
stalks could be used as a raw material for anaerobic fermentation (Adebayo et al. 2014; Bruni 2010; Zhong et
al. 2011). A pretreatment process is required to decompose cellulose to reduce the volume of material and
increase production of biogas (Antognoni et al. 2013).
Based on these facts and problems associated with
disposal of these wastes, this study evaluated the
potential of these wastes (vinasse and maize stalks) as
substrates for co-digestion. Co-digestion is the simultaneous digestion of a homogenous mixture of two
or more substrates. The most common situation is
when a major amount of a main basic substrate (such
as manure or sewage sludge) is mixed and digested
together with minor amounts of a single, or a variety
of additional substrates.
296
DOI 10.1201/9781003221968-39