Waste from
slaughterhouses is a global concern as the sector generates huge quantities of
animal organic waste, often on a daily basis. Slaughterhouse waste has high
organic content, making it an attractive feedstock for anaerobic digestion
(AD), which produces biogas through a series of biochemical processes. In this
study, the performance of an operating biogas plant using slaughterhouse waste
was investigated to improve its operation and hence protect the environment
from pollution coming from slaughterhouse waste and provide energy and
potential revenue to the slaughterhouse facility. Important parameters for a
biodigester that were investigated in the performance analysis are the design
specification, actual production, feedstock availability and environmental
impact of the facility. The study was conducted at Nyongara slaughterhouse,
Dagoretti, located some 26km away from Nairobi City centre. Both primary and
secondary data were collected and used in the research. Data was analysed and
presented using descriptive statistics. The collected data were compared to
those of an ideal biogas plant. The study established that the existing and
operating biogas plant is not operating at optimum conditions. The
slaughterhouse generates about 56,000 kg of solid and liquid waste daily, out
of which only 2,800 kg is utilised, which represents just 5% waste utilisation
by the biodigester. The biodigester performance is about 70% of the optimum
biogas production, while only 5% of biodegradable waste is digested, leaving 95%
for disposal, undigested, leading to severe environmental pollution and high
disposal costs. The investigation recommends increase in average digestion
temperature to 37°C from 34°C, change of substrate to water mixing ratio from
1:2.5 to 1:1, increase of the pH from average of 6.5 to 7, reduction in
hydraulic pressure from 400 mm to 350 mm of water by reducing average height of
the substrate in the digester and increase in residence time from 17 to 20
days. The proposed modifications to the digestion operating conditions are
expected to increase the biogas production from 35 m3 per day to 48 m3 per day,
which is a 37% increase in production.
Author(s) Details
Moses Jeremiah Barasa Kabeyi
Industrial
Engineering Department, Durban University of Technology, Durban, South Africa.
Oludolapo Akanni Olanrewaju
Industrial
Engineering Department, Durban University of Technology, Durban, South Africa.
Please see
the link:- https://doi.org/10.9734/bpi/erpra/v12/5667
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