Assessing biogas recovery potential from organic Solid waste generated from academic institutions (case study: Islamic university in Uganda - Mbale city)

Abstract

Resource recovery is contingent to the circular economy and the core intention is to replace the norm of largely linear economy of take make and dispose with one where resource circulation and disposal is fostered at high value. One of the current trending strategies in waste minimization is resource recovery such as biogas given its undisputable benefits. Education institutions are considered as congregated communities that have significant social, economic and environmental impact on the environment. like local authorities, these institutions experience challenges of provision of satisfactory social services such as managing solid waste. Minimal efforts have been invested in carrying out research in waste management practices in school settings most especially establishing the potential of biogas recovery that can contribute towards reduced impact to the ecosystem. This study was therefore focused on exploring the biogas potential from solid organic waste generated from higher academic institutions in Mbale Municipality. The study first looked at solid waste management practices in sampled academic institutions and their respective main source of fuel for cooking; a checklist was prepared and 26 out of 36 sampled institutions willingly provided access to their premise. From the data gathered, 65% of the 26 institutions practiced onsite waste disposal mainly dumping in pits and burning while the other schools disposed of to the main landfill; 25 out 26 institutions utilized wood biofuels for cooking while 1 out of the 26 used electricity; none of the schools practiced resource recovery. A detailed assessment was then undertaken at Islamic University in Uganda to establish the quantity and composition of the waste generated within two distinct periods of the semester: one at the beginning (February) that represented the dry weather conditions and at the end of the semester (November) that represented the wet season. Results indicated that foliage pruning contributed the highest percentage of waste generated followed by kitchen waste while paper waste registered the least percentage contribution by both volume and weight; It was also noted that more waste generation was experienced during the wet season; hourly waste collection indicated peak collection/ generation between 1000-1200 while least collection was between 1200-1400hr with kitchen waste dominating between 0800-1000hrs and 1600- 1800 while foliage pruning dominated between 1000-1200hrs and 1200-1400hrs respectively. Biogas resource potential was investigated using a single stage biogas setup where co-digestion of the organic solid waste was used as substrate; eight sets of experiments were conducted with two identical sets per ratio for (paper, kitchen and grass) and 25% cow dung inoculant by weight of the total substrate weight under mesospheric conditions. Results indicated a high methane composition of 33% and a relatively low percentage of 13% for ratios of 1:19:7 and 1:5:7 (for paper: kitchen: grass) respectively. The potential of biogas in solid organic waste gave an indication of a virgin opportunity to explore harnessing resources from the organic waste generated from academic institutions that will in return provide an alternative for safe solid waste disposal as well as harnessing nature gas for cooking and manure for soil stabilization for ecosystem degradation mitigation. Key Words: Resource recovery, Biogas, Solid Organic Waste, Methane