Municipal Solid Waste Management in a Low Income Economy Through Biogas and Bioethanol Production

The biodegradable fraction of municipal solid
wastes generated from households in Ghana has favourable
characteristics worth considering for bioenergy production.
The suitability of this biodegradable portion for biogas and
bioethanol production was assessed in this study. The
assessment was performed on both untreated and
hydrothermally treated unsorted and sorted fractions of the
waste using standard methods for biomass conversion to
bioenergy. Compositional analysis of the waste indicated
that unsorted biodegradable municipal solid wastes
(BMSW) consisted of 38.7 % dry matter (DM) glucan,
8.3 % DM hemicellulose, 10.1 % DM lignin and 7.6 %
DM ash. The sorted fractions with the highest glucan but
least lignin and hemicellulose were the pool of cassava,
yam and plantain peeling wastes (CYPPW) with 84 % DM
glucan much of which was starch, 5.6 % DM lignin and
0.5 % DM hemicellulose. The highest ethanol yield of
0.29 l/kg DM was measured from this same CYPPW while
fruit wastes (FW) had the highest biomethane potential of
408 ml CH4/g VS. The BMSW had ethanol yield of 0.17 l/
kg DM and biogas 369 ml CH4/g VS. The hydrothermally
pretreated wastes had marginal increases in glucose and
ethanol yield except the treated yard waste which
significantly increased by 54 % in glucose over the
untreated waste. The most promising waste fractions were
FW, CYPPW and mixed paper wastes. Careful selection of
these fractions in feedstock for biofuel production would
reduce generation of the waste, improve the quality and
effectively lead to higher yield of biofuel over the unsorted
form.