Optimization, Design and Construction of an Experimental Biogas System in a Small Dairy in Colombia
Gil-Donato, Juan A
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With the global population reaching approximately 9.7 billion by 2050, questions on how life’s necessities - food, energy, water, and infrastructure - will be supplied are becoming more relevant. These necessities generate specific challenges and demand prompt and appropriate solutions. Energy, with its ability to power cities, industry, rural farms, and everyday households, poses a challenge to many regions of the world, especially to those populations located outside major metropolises. This is part of the reason why the development and implementation of alternative energies are being held in the forefront of affordable sustainability. Alternative energies have already played a critical role in today’s world by providing on-site energy generation with the adoption of different technologies. For example, anaerobic digestion (AD) is a technology that is being employed by rural communities in emerging countries to improve the quality of life. This alternative technology offers several benefits that could address some of the energy and environmental needs that these communities have incurred. Among those benefits, AD provides clean fuel for cooking, heating, and electricity generation. It is also used to treat wastewater, capture greenhouse gases (GHGs), and produce as an excellent fertilizer for crops. These benefits are more evident in agricultural operations where biomass residues can be used to generate heating or electric energy while offsetting part or all of the operational costs. Biogas systems can be a practical and cost-effective solution to energy generation, allowing small, remote, urban, or rural communities to establish and take full advantage of the benefits. Countries all over the world are promoting and incentivizing rural communities and farms to adopt and utilize this technology, substituting electricity, propane, butane, natural gas, and kerosene. Several countries in Central and South America are implementing AD on a smaller scale compared with eastern countries, normally encouraged by private and public initiatives. Colombia, as an example, is working on determining whether alternative energies should be heavily promoted and subsidized, and if programs encouraging and facilitating people to adopt renewable energies should be carried out. Several challenging factors of this technology need to be addressed to guarantee its success in the most demanding conditions. Currently, most of these solutions are neither cost-effective nor practical. Biogas systems in Colombia have been adopted, mostly by small and medium agricultural operations to generate biogas. However, the extent of the technology implementation is not known. One of the objectives of the World Bank, World Health Organization and United Nations Environmental Programme is to reduce the reliance on fuel wood as a heating and cooking system. The use of indoor biomass as a fuel has been attributed to respiratory illness at an estimated loss in human productivity of 110 million disability-adjusted life years (Putti, Tsan, Mehta, and Kammila, 2015). Exposure of children to wood and other biomass burning fumes can result in long-term respiratory illness (WHO, 2012). Due to the rural demographics and availability of costly traditional alternative energy sources being limited, biogas offers a healthy and cost-effective alternative to the traditional wood fuel option. The purpose of this research was to design an optimized, rugged, cost-effective, weather-resistant, low-maintenance biogas system, capable of withstanding UV degradation, and be puncture-resistant while staying cost-effective and easy to use and maintain. The dairy sector was selected due to its location in rural distribution, high organic content load, and large amount of water use, making it a perfect candidate for anaerobic digestion. This research project was composed of three components: (1) an evaluation phase, to determine the best concentration of solids to water ratio, (2) an optimization phase, to determine how physical chemical parameters affect biogas generation, and (3) an implementation phase, where a biogas system was designed and assembled in a dairy operation located in a rural region of Colombia. This system was designed using high-density polyethylene (HDPE) of 40 mil thickness, which has demonstrated a high resistance to environmental factors and physical damage (Topliff, thesis in preparation). This demonstration was conducted to identify construction needs, resistance, biogas output, as well as local acceptance and interest. The biogas system has the secondary benefit of enhancing micro and macro farming operation (dairy and crops) by substituting costly chemical fertilizers with the biogas effluent, increasing farm resilience and reducing operational costs. The research project was demonstrated at a field day to the local rural community of Victoria, Caldas, and also to several private and public institutions. The goal was to demonstrate the benefits of a biogas system and to address any misconceptions regarding the installation requirements, maintenance, and costs. Among the attendees were local political candidates, swine farmers, cattle ranchers, dairy/cheese producers, waste management companies, Servicio Nacional de Aprendizaje – SENA (Learning National Service), the University of Caldas, and other nearby communities interested in the project. The project proved to be a successful technical and social experience and is, at present, fully operational, generating 1m3 or three hours of continuous burning gas per day. Community members continue to visit the biogas system, to learn, and integrate biogas into their own operations. One valuable lesson was the need for a comprehensive program to involve the women in the project and to inform them of the health and environmental benefits of using clean and safe biogas.