The conversion of organic waste material to energy can proceed along three main pathways – thermochemical, biochemical and physicochemical. Thermochemical conversion, characterized by higher temperature and conversion rates, is best suited for lower moisture feedstock and is generally less selective for products. Thermochemical conversion includes incineration, pyrolysis and gasification. The incineration technology is the controlled combustion of waste with the recovery of heat to produce steam which in turn produces power through steam turbines. Pyrolysis and gasification represent refined thermal treatment methods as alternatives to incineration and are characterized by the transformation of the waste into product gas as energy carrier for later combustion in, for example, a boiler or a gas engine. Bio-chemical conversion processes, which include anaerobic digestion and fermentation, are preferred for wastes having high percentage of organic biodegradable (putrescible) matter and high moisture content. Anaerobic digestion is a biological treatment method that can be used to recover both nutrients and energy contained in organic wastes such as animal manure. The process generates gases with a high content of methane (55–70 %) as well as biofertilizer. Alcohol fermentation is the transformation of organic fraction of waste to ethanol by a series of biochemical reactions using specialized microorganisms. The physico-chemical technology involves various processes to improve physical and chemical properties of solid waste. The combustible fraction of the waste is converted into high-energy fuel pellets which may be used in steam generation. The waste is first dried to bring down the high moisture levels. Sand, grit, and other incombustible matter were then mechanically separated before the waste is compacted and converted into pellets. Fuel pellets have several distinct advantages over coal and wood because it is cleaner, free from incombustibles, has lower ash and moisture contents, is of uniform size, cost-effective, and eco-friendly.
The Middle East and North Africa (MENA) region is highly susceptible to climate change, on account of its water scarcity, high dependence on climate-sensitive agriculture, concentration of population and economic activity in urban coastal zones, and the presence of conflict-affected areas. Moreover, the region is one of the biggest contributors to greenhouse gas emissions on account of its thriving oil and gas industry. The world’s dependence on Middle East energy resources has caused the region to have some of the largest carbon footprints per capita worldwide. Not surprisingly, the carbon emissions from UAE are approximately 55 tons per capita, which is more than double the US per capita footprint of 22 tons per year. The MENA region is now gearing up to meet the challenge of global warming, as with the rapid growth of the carbon market. During the last few years, many MENA countries, like UAE, Qatar, Egypt and Saudi Arabia have unveiled multi-billion dollar investment plans i...