Biogas Potential From Slaughterhouse Wastes at Ambient Temperatures in Lira Municipality of Northern Uganda

Abstract

The generation of biodegradable solid waste and wastewaters is characteristic of all slaughterhouses including the Lira Municipality slaughterhouse (LMS) in northern Uganda. However, the LMS is not properly designed to handle and manage the ever-increasing biodegradable solid waste and wastewater. The wastes discharged from LMS, contain reasonable amounts of paunch, fat, grease, undigested food, diluted blood, suspended material, urine, loose meat and soluble protein. The lack of a properly designed slaughterhouse in Lira Municipality, needed to manage and handle the waste has resulted in the discharge of the waste into the environment, leading to pollution of water sources, outbreaks of diseases, and production of unfavorable odors. The objective of this study was to investigate the biogas potential of the LMS biodegradable solid waste and wastewaters at ambient temperatures. The waste was quantified based on Measurement at the point of generation method. Representative samples were characterized for biogas potential. Five treatments of the waste replicated three times were anaerobically digested in 1500mL batch digesters with a working volume of 750mL. Treatment A contained only the inoculum and inoculum in the other treatments B, C, D, and E was approximately 20% of the volume of the substrate. Substrate: water ratio of 1:1, maintained pH of 6.0- 7.0 and retention time of 30 days were used for the study under ambient conditions. On average, 2,597 L, 40 kg and 502 kg of wastewater, cow dung and punch manure respectively were produced from LMS. The quantity and methane content of the biogas ranged from 1029.6 to 3512.7 ml/gVS and 40.6 to 50.4% respectively. Therefore, slaughterhouse wastes are potential sources of biogas production at ambient temperatures.

Impact of Thermal Pretreatment on the Physicochemical Characteristics and Biomethane Yield Potential of Solid Slaughter Waste from High-Throughput Red Meat Abattoirs Valorized as a Potential Feedstock for Biogas Production

“…Other authors have reported that sterilization causes the accumulation of microbial metabolic waste including the accumulation of metabolic acids which may impact the hydrolysis stage, thus affecting the microbial activity required for AD [14,54,59,60,74]. This also supports the findings reported by Kavuma et al [15], who observed in their study that sterilization may alter the environmental conditions necessary for microbial growth due to the hypertonic environment caused by the high temperature and pressure during pre-treatment, which in turn reduced gas production during the early days of AD and led to the reduction in food nutrients necessary to support microbial growth. The highest methane yields were obtained in sterilized pre-treated cattle waste despite its low biomethane production from day 1 to day 23 (Figure 2) as compared to the control and pasteurized cattle abattoir waste.…”

“…The biogas composition in this study ranged from 54.69 ± 1.66% to 65.17 ± 3.99% CH 4 , 129 ± 10.87 to 177 ± 36.98 ppm NH 3 , 24.83 ± 1.17% to 39.4 ± 2.18% CO 2 , 0.4 ± 0.00% to 1.6 ± 0.03% O 2 , and 113 ± 33.74 ppm to 318 ± 31.56 ppm H 2 S. The H 2 S has been reported to cause corrosion in digesters and may lead to a further impact on methanogen activity due to sulfide inhibition [76,79]. The results in this study were higher compared to those observed by Kavuma et al [15], who observed a methane volume range of 40.6% to 50.4%. The methane composition in this study was also higher than that reported by Budiyono et al [46], where they observed a biogas CH 4 volume of about 48.89%.…”

“…South Africa is a developing country with an agriculture-intensive industry, currently comprising about 430 abattoirs, with about 285 high-throughput red meat abattoirs registered, slaughtering over a million cattle, pigs, and sheep on an annual basis. South Africa is also the largest meat producer and exporter in Africa [9,15,16]. Currently, waste management at high-throughput red meat abattoir facilities in South Africa is difficult, and most local municipalities across the country have banned the disposal of this waste, especially solid slaughter waste in landfills, due to the high cost incurred during its treatment.…”