Agricultural Wastes – A Promising Source for Biogas Production in Developing Countries of the Tropical and Subtropical Regions

Abstract

Most of the so called developing countries are located in tropical and/or sub-tropical regions whilst in contrast, most of the developed countries are in the temperate climate zones. It is expected that a huge increase in the future global energy consumption will be caused by the demand of the developing countries. Caused by the favourable climate conditions in tropical and/or sub-tropical regions the average productivity of biomass is 4 – 5 times higher than that of biomass grown in the temperate regions. Many of the developing countries today are agricultural and agro-industrial countries producing huge amounts of agricultural residues and wastes that can be used as source for energy generation. It is estimated that if only all process-based agricultural residues alone would be used, they could contribute between 25 % and 40 % of the total primary energy demand in such regions [1]. Until now, the huge amount of agricultural waste generated each year in developing countries is a headache for farmers, who are obliged to get rid of it. Open field burning and improper disposal are omnipresent in many regions and pollute the environment. Converting such waste into bioenergy such as biogas by using anaerobic digestion technologies represents an alternative treatment with a promising potential. Such treatment prevents pollution, is producing valuable and climate friendly energy and will contribute to nutrient recovery by using the digestate as fertilizer. The paper will introduce some of the most promising agricultural residues in tropical and subtropical regions which can be used as substrates or co-substrates for biogas production. Results of a research project carried out in Costa Rica will be used as a case study to show the potential of two of the major agricultural residues (pineapple and banana residues) as sources for biogas production. The opportunities and prospects for the dissemination and implementation of new and more developed technologies to improve the efficiency of the technologies will be shown.

Biowastes as a Potential Energy Source in Africa

“…Table 1 reports the FAO estimate of biowastes. Africa is located in tropical and subtropical region and due to good climate conditions; production rate of biomass is 4-5 times the other regions [14] leading to high agricultural and forest wastes. In 2012, 11.519 Gt was produced and 5.098 Gt was collected and in 2025, 28.155 Gt and 18.232 Gt are expected to be produced and collected every year [4].…”

“…These wastes can be a good source of energy if they are successfully transformed. For example, in 2019 Barz et al reported that if agricultural wastes are properly handled, they can contribute 20-40%ofprimaryenergy [14], demonstrating that all biowastes can contribute significantly. According to estimates, processing crop and agro-processing leftovers might provide 4.2 EJ in 2030, forest Residue 1.1 EJ, and animal residue 1.5 EJ.…”

“…According to estimates, processing crop and agro-processing leftovers might provide 4.2 EJ in 2030, forest Residue 1.1 EJ, and animal residue 1.5 EJ. To reduce competing with food in the production of fuel, boost waste economic value, and safeguard the environment (lower GHG), biowastes should be successfully employed as an energy source [14]. The most difficult challenge is to invest in an efficient method of collecting and converting it.…”

A Review of Intermediate Pyrolysis as a Technology of Biomass Conversion for Coproduction of Biooil and Adsorption Biochar

“…Poor treatment of wastes that lead to pollution and loss of energy is common in developing countries. If these wastes are well treated can generate 20-40% of primary energy in developing countries [123] and if well converted can help to reduce the pressure of feedstocks for biooil and adsorption biochar production.…”

Uso de baterías alcalinas agotadas para activar carbón de granza de arroz

“…In the case of Costa Rica, there is potential of using lignocellulose residues from forestry and waste from the production of palm oil and pineapple [13]. Banana [14], rice, sugar cane and coffee waste are also potential sources of carbon [15]. Rice husk, discarded from the rice milling process, has a reported mass composition of 66.67 % carbon, 22.30 % SiO2, 7.10 % H 2 O, 0.82 Al 2 O 3 , 0.78 % Fe 2 O 3 , 1.10 % K 2 O, 0.78 % Na 2 O, 0.24 % CaO and 0.21 % MgO, this composition varies depending on the crop location and soil preparation.…”