Effect of Variation in Co-Digestion Ratios of Matooke, Cassava and Sweet Potato Peels on Hydraulic Retention Time, Methane Yield and Its Kinetics
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Sustainable Bioenergy Systems
Abstract
This paper presents the results of batch anaerobic co-digestion of matooke, cassava,
and sweet potato peels and vines. These agricultural wastes and others form the biggest
portion of household wastes in developing countries. However, they have remained
an unexploited resource amidst the ever increasing needs of clean energy and
waste disposal challenges. Efforts to use them individually as biogas substrates have
been associated with process acidification failure resulting from their fast hydrolysis.
The aim of this work was to exploit agricultural wastes is co-digestion among themselves
and assess their effect on methane yield and its kinetics, pH and hydraulic retention
time (HRT). Sixteen ratios of Matooke peels (MP), cassava peels (CP) and
sweet potato peels (SP) were assessed in duplicate. Methane yield and its kinetics, pH
and HRT demonstrated dependence on the proportion of substrates in the mixture.
Depending on the ratio mixture, HRT increased to 15 days compared to less than 5
days for single substrates, hydrolysis rate constant (k) reduced to a range of 0.1 - 0.3
d−1 compared to single substrates whose k-values were above 0.5 d−1, pH was maintained
in the range of 6.38 - 6.43 and CH4 yield increased by 15% - 200%. Ratios 2:1:0,
2:0:1, 0:1:2, 1:1:1 and 1:1:4 were consistent all through in terms of model fitting, having
a positive synergetic effect on HRT, hydrolysis rate constant, lag phase and methane
yield. However, more research is needed in maintaining the pH near the neutral
for process stability assurance if household wastes are to be used as standalone
substrates for biogas production without being co-substrates with livestock manure.
Description
Keywords
Co-Digestion, Household Wastes, Hydrolysis, Methane Yield, Kinetics
Citation
Tumutegyereize, P., Ketlogetswe, C., Gandure, J. and Banadda, N. (2016) Effect of Variation in Co-Digestion Ratios of Matooke, Cassava and Sweet Potato Peels on Hydraulic Retention Time, Methane Yield and Its Kinetics. Journal of Sustainable Bioenergy Systems , 6, 93-115. http://dx.doi.org/10.4236/jsbs.2016.64009