Dinesh Surroop

Comparative assessment of anaerobic digestion of municipal solid waste at mesophilic and thermophilic temperatures

Anaerobic digestion is an environmentally sound treatment option for the organic fraction of municipal solid waste (OFMSW) and simultaneously producing methane gas which is a source of renewable energy. The COD reduction of the substrate was 72% for the mesophilic condition and 72.3% for the thermophilic condition. 1200 cm³ of methane was produced in the mesophilic condition and 1260 cm³ in the thermophilic condition. The methane content, by volume, in the biogas was found to be 60% and 63% in the mesophilic and thermophilic condition respectively. It was also found that 0.723 cm³ of methane per unit weight of substrate was produced at the mesophilic condition and 0.760 cm³ of methane per unit weight of substrate at the thermophilic condition. The gas production rate for mesophilic and thermophilic condition were 0.0214 m³ (m³d)−1 and 0.046 m³ (m³d)−1 respectively and the methane yield was more or less the same in both cases. The methane yield in mesophilic condition was 0.0614 m³/kg COD and that at thermophilic condition was 0.0612 m³/kg COD.

Assessing the potential of biofuel (biochar) production from food wastes through thermal treatment

This work primarily investigated the feasibility of generating high quality biochar from food wastes (FW) torrefaction. The thermal behavior of FW torrefaction was studied between 225 and 300°C for 1 and 3h at a fixed heating rate of 15°C/min. Torrefaction upgraded the energy density, calorific value and carbon content of FW compared to the untreated feedstock. Mass loss constituted a good measure of the reactivity and ease of degradation of FW based on the cumulative effect of time and temperature. The fuel properties of torrefied FW approached those of coal whilst their high energy yields confirmed their use as potential coal substitutes in thermal conversion systems. Torrefaction at 275°C at both residence times were optimal while severe torrefaction at 300°C for 3h was energetically inefficient. FTIR analysis and the increased HHV of bio-oil fractions revealed that bio-oil could be used to produce value-added chemicals and biofuels upon upgrading.

Lifelong Learning (LLL) for Energy Practitioners in Small Island Developing States (SIDS): The Pivotal Role of Education in Energy Efficiency and Demand Side Management

Climate change issue in SIDS is real and alarming. While shifting to more sustainable energy resources is a feasible option to curb down climate change impacts, there are still some barriers to overcome to do so. Energy efficiency is another option to mitigate climate change impacts. Past studies showed that energy efficiency is more effective through education and awareness. In the context of SIDS, their energy sector is characterised by poor electrification rates, high dependence on oil and less ability to cope with volatile oil prices and ironically, past studies showed that energy practitioners in SIDS, some if not most, have a lack of knowledge on energy issues in small island communities. Therefore, there is a need to train energy practitioners in SIDS who can hopefully contribute to transform SIDS energy sector into a sustainable and dynamic one. The aim of this study is to highlight the importance and barriers of educating energy practitioners on energy efficiency. In this study, in the foremost energy issues in SIDS are highlighted. The study is focussed on the need to achieve an energy efficient culture in a workplace and how it can be achieved through education. A proposed content on an energy efficiency programme is outlined. Issues and challenges for energy efficiency education is included and an opportunity to address these issues through global corporation is included. This study can help to refocus attention on energy efficiency in SIDS, and motivate energy practitioners to come up with energy efficiency practices at their workplaces.

Feasibility of Using Solar Energy as a Source of Renewable Energy in Mauritius Under Collaboration of DIREKT

With limited indigenous conventional energy resources, Mauritius imports over 80 % of its energy supply from foreign countries, mostly from the Middle East. Developing independent renewable energy resources is thus of priority concern for the Mauritian government. Mauritius, being a tropical island surrounded by the Indian Ocean has enormous potential to develop various renewable energies, such as solar, biomass, wind power and geothermal energy. In order to reduce external dependency of fuel the Mauritian Government introduced attractive policies and invited investors of the homeland and abroad to invest in renewable energy technologies. Thus, the aim of this study was to determine the feasibility of implementing solar photovoltaic panels at institutional and organizational level and determine its economical feasibility. The study also consisted of determining the extent to which Mauritians are ready to accept such technologies. A research was thus carried out in collaboration with DIREKT and was found that Mauritians are eager to accept and invest in the solar photovoltaic technology provided that they are given sufficient information on how the system works. Moreover, the economic evaluation for the implementation of the photovoltaic technology revealed that the payback period for such technologies will be around 4.3 years which is very much acceptable.

Anaerobic Digestion of Vegetable Wastes Using Biochemical Methane Potential Assays

Solid wastes generation is a major problem in Mauritius in terms of wastes disposal with vegetable wastes representing 40–46 % the organic waste stream by mass. This study focused on the anaerobic digestion (AD) of vegetable wastes using biochemical methane potential (BMP) assays to assess the performance of AD processes in treating these wastes in a sustainable manner. 2,000 mL plastic bottles were used as anaerobic digesters for the assays and the vegetable wastes comprising of carrots, potatoes, cabbage and beetroots were ground and seeded with inoculum in a ratio 4:1 (volume basis). The inoculum used was mature sludge taken from an anaerobic digester treating cattle wastes. The inoculated substrates were then fed in the digesters, purged with N2 and sealed with rubber septum. The AD process was allowed to run over a hydraulic retention time (HRT) of 20 days. Results showed a total solids (TS) reduction of 62.1 %, volatile solids (VS) reduction of 66.4 % and COD reduction of 64.9 % which demonstrated effective degradation of the substrates during the digestion process. The biogas yield was 0.360 L/g VS fed and this value was in agreement with published data. These results hence showed that vegetable wastes can be effectively treated by AD. The next phases of the study consist in investigating the AD process of wastewater treatment sludge and the effects of sonication on AD of vegetable wastes and sludge, with special emphasis on process parameters.

Strategies Developed by DIREKT for the Small Island Developing States to Enhance Renewable Energy Utilisation

Given the current global situation of scarce energy resources, rapidly rising fossil-fuel prices and drastic climate changes, it is recognised that the promotion and application of Renewable Energy (RE) and Energy Efficient (EE) technologies is of vital importance for sustainable socioeconomic development in the Small Island Developing States (SIDS). The DIREKT network (Small Developing Island Renewable Energy Knowledge and Technology Transfer) is a teamwork scheme that involves the participation and collaboration of various universities from Germany, Fiji, Mauritius, Barbados and Trinidad and Tobago. The aim of the DIREKT project is to reinforce science and technology competency in the domain of renewable energy through technology transfer, information exchange and networking, targeting ACP (Africa, Caribbean, Pacific) SIDS as they are more vulnerable to problems associated with climate change. The overall objectives of the DIREKT project consist, basically, of enhancing sustainable collaboration between the participant countries and the EU, and transferring research results on the key topic of renewable energies, by putting into operation “technology transfer centres” in the participant countries. To help in achieving these aims, the partners of the DIREKT project have set up short-term, medium-term and long-term strategies to be applied to SIDS.

A Review of Thermochemical Technologies for the Conversion of Waste Biomass to Biofuel and Energy in Developing Countries

Rising energy security concerns associated with the depleting fossil fuel reserves have triggered renewed interests in the utilisation of biomass for energy. Highly vulnerable to the energy instability, developing countries are turning to thermochemical technologies for the conversion of biomass to biofuels to displace the use of the traditional fossil fuels. A comparative analysis of the potentials of thermochemical conversion technologies of biomass to biofuels and energy in developing countries was conducted. The current status of biomass combustion, cogeneration, gasification, pyrolysis and torrefaction were assessed in different emerging economies, namely, South Africa, Ghana, Malaysia, China, India, Thailand, Tanzania, Brazil and Mauritius. Biomass combustion and cogeneration held the foothold at commercial level both in industrialised and developing countries based on technology maturity and reliability. Biomass gasification is evolving as an eminent method for the production of energy and power in various developing countries. India and China have already embarked on the commercialisation of biomass gasification projects, while other nations have enrolled on pilot-scale schemes. The effectiveness, versatility and environment-friendly aspect of biomass gasification have favoured its preferred integration in the energy system in contrast to combustion and other techniques. Biomass pyrolysis is as promising as gasification in the production of pyrolysis oil to generate transportation fuels. Presently limited at demonstration scale, pyrolysis is being extensively investigated to promote its rapid scale-up and commercial application. Pyrolysis oil represents a crucial resource for the generation of other biofuels, chemicals and power. Torrefaction is a desirable pre-treatment prior to advanced thermal treatment of biomass as it enhances the energy density of processed biomass. Still in its infancy, torrefaction is recurrently being studied to facilitate its large-scale application. The reluctance to adopt biomass thermochemical conversion technologies in developing countries is accounted by economical, technical and social issues. Thermochemical conversion of biomass to biofuel can become important Clean Development Mechanism (CDM) projects with mitigated greenhouse gas (GHG) emissions in the long run.

Investigating the Potential of Using Coconut Oil–Diesel Blends in a Diesel Engine in Rodriques Islands

The transportation sector of Rodrigues Island is fully dependent on petroleum products, mainly diesel and to a lesser extent gasoline. As an alternative solution to reduce the consumption of petroleum product over the island, this study was thus conducted to assess the performances of coconut oil–diesel blends in a diesel engine in Rodrigues Island. The fuel properties of coconut oil blends in this study were comparable to those of diesel. The engine performance showed that the mechanical efficiency of diesel was 71 % and that of the blends were around 71–77 %. The brake specific fuel consumption (BSFC) for both diesel and blends were around 0.5 kg/kWh with engine revolution below 1,500 rpm; but above 1,500 rpm the BSFC of the blends were twice as much as that of diesel. A reduction in carbon dioxide and carbon monoxide emissions were achieved up to 16.46 and 22.81 % respectively. The land requirement for the production of coconut oil to substitute 5 and 25 % of actual diesel consumption was 0.95 and 4.73 % respectively of the total area of Rodrigues Island. The economic analysis showed that a coconut oil production plant was profitable with payback periods ranging from 4.16 years for 5 %—COCO to 1.82 years for 25 %—COCO. Potential savings on diesel importation could range from Rs. 8,630,400 to Rs. 43,152,000.

Software and Information Technology Support in a Virtual Renewable Energy Laboratory, Based on Areal Physical Environment—ECO UQAR—UOM Potential Collaboration

The present project aims to propose a new training approach based on communication and information technologies, which can be easily exported to different universities interested in growing and diversifying, such as the University of Mauritius. Specialized software and information technology is used to develop a virtual platform of a real, physical renewable energy laboratory, shared with different users and clients via VPN services and global web-based services. From an engineering point of view, the concept is simple, but the computer and information technology requirements are challenging. ECO-UQAR is a new entity created at the Universite du Quebec a Rimouski, and aims to provide “learn by projects” training in the field of renewable energy. A physical laboratory has been set up for this purpose. The physical set-up consists of a wind blower, wind turbines, solar panels, irradiation systems and other standard equipment. The whole laboratory is completely instrumented. Specialized software is used for data acquisition, data transfer and data processing. In this paper, the emphasis is placed on the virtual environment that is set up using LabView, the data transfer from remote wind turbine installations to the laboratory, the data acquisition within the laboratory, and the security involved in using such a system. Specialized training is offered on high-level software, as a final step. This paper focuses on one particular project, whereby such software is used to illustrate the computational challenges involved in the use of specialized high-level software.

Optimization of Biogas Production to Use in Cooking Stove

The objective of this project is to enhance the biogas production from anaerobic digestion of resources, like organic wastes, which are readily available on the island. The project laid emphasis on the optimization of the process which includes methods available up to date to enhance the biogas production. Anaerobic Digestion is the biological treatment of biodegradable organic waste in the absence of oxygen, utilizing microbial activity to break down the waste in a controlled environment. Anaerobic digestion results in the generation of biogas; which is rich in methane, were used to generate heat in a cooking stove. The digestate which is nutrient rich can potentially be used as a soil conditioner or as fertilizer. The digestion process took place in a sealed airtight container (the digester) which was the ideal conditions for the bacteria to ferment the organic material in oxygen-free conditions. A pilot anaerobic digester of 1 m3 was designed proposed whereby cow dung was used as feed to operate the digester. The digester consisted of a mixing unit integrated inside. The digester was then connected to a holder whereby it was used as a biogas storage system. From there on, the biogas was sent to a stove for cooking purposes. Plastics tank were selected as the main material for the design since it was easily available on the market and had low investment cost. This kind of project would be implemented at farmers or lower middle class people who reared cows, since the feed is readily available. This project was feasible for typical Mauritian family in terms of technical, social and economical factors.