Waste-to-Energy Outlook for Jordan

A “waste crisis” is looming in Jordan with more than 2 million tons of municipal waste and 18,000 tons of industrial wastes being generated each year at an annual growth rate of 3 percent. Alarmingly, less than 5 per cent of solid waste is currently recycled in Jordan. These statistics call for a national master plan in order to reduce, manage and control waste management in the country. The main points to be considered are decentralized waste management, recycling strategy and use of modern waste management technologies. Currently there is no specific legal framework or national strategy for solid waste management in Jordan which is seriously hampering efforts to resolve waste management situation.

Waste can be converted into energy by conventional technologies (such as incineration, mass-burn, anaerobic digestion and landfill gas capture). Municipal solid waste can also be efficiently converted into energy and fuels by advanced thermal technologies, such as gasification and pyrolysis. Landfill gas capture projects represent an attractive opportunity for Jordan as huge landfills/dumpsites are present in all cities and towns.

A 1 MW pilot demonstration project using municipal solid waste (MSW) through landfill and biogas technology systems was constructed and commissioned in 2001.  The project was expanded in 2008 to about 4 MW.  Jordan plans to introduce about 40-50 MW waste energy power projects by 2020. However, biomass energy projects offer a low potential in Jordan because of the severe constraints on vegetation growth imposed by the arid climate. It has been estimated that animal and solid wastes in Jordan represent an energy potential of about 105 toe annually, but municipal solid waste represents a major fraction with a gross annual production rate of more than 2 million tons.

More than 80% of actual total manure generation is concentrated in 4 northern Governorates Al Zarqa, Amman, Al-Mafraq and Irbid. More than 80% of cattle manure is being produced in three northern Governorates Al-Zarqa, Al-Mafraq and Irbid. More than 80% of poultry manure production is located in 5 northern Governorates Amman, Irbid, Al-Zarqa, Al-Mafraq and Al-Karak. An exception is sheep manure. More than 90% of sheep manure is available in three Governorates Aqaba (40%), Al-Mafraq (25%) and Al-Zarqa (25%).

Conclusion

In Jordan, waste-to-energy can be applied at small-scale for heating/cooking purposes, or it can be used at a large-scale for power generation and industrial heating. Waste-to-energy can thus be adapted rural as well as or urban environments in the country, and utilized in domestic, commercial or industrial applications.

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What is Waste-to-Energy

Energy is the driving force for development in all countries of the world. The increasing clamor for energy and satisfying it with a combination of conventional and renewable resources is a big challenge. Accompanying energy problems in different parts of the world, another problem that is assuming critical proportions is that of urban waste accumulation.

The quantity of waste produced all over the world amounted to more than 12 billion tons in 2006, which increased to 13 billion tons in 2011. The rapid increase in population coupled with changing lifestyle and consumption patterns is expected to result in an exponential increase in waste generation of upto 18 billion tons by the year 2020.

Waste generation rates are affected by socio-economic development, degree of industrialization, and climate. Generally, the greater the economic prosperity and the higher percentage of urban population, the greater the amount of solid waste produced.

GCC countries are well-known for being the world’s top-ranked per capita waste generators. Reduction in the volume and mass of solid waste is a crucial issue especially in the light of limited availability of final disposal sites in the MENA countries. Millions of tons of waste are generated each year in the Middle East with the vast majority disposed of in open fields or burnt wantonly.

What is Waste to Energy

Waste-to-Energy (or WTE) is the use of modern combustion and biochemical technologies to recover energy, usually in the form of electricity and steam, from urban wastes. These new technologies can reduce the volume of the original waste by 90%, depending upon composition and use of outputs. The main categories of waste-to-energy technologies are physical technologies, which process waste to make it more useful as fuel; thermal technologies, which can yield heat, fuel oil, or syngas from both organic and inorganic wastes; and biological technologies, in which bacterial fermentation is used to digest organic wastes to yield fuel.

 

The three principal methods of thermochemical conversion corresponding to each of these energy carriers are combustion in excess air, gasification in reduced air, and pyrolysis in the absence of air. The most common technique for producing both heat and electrical energy from wastes is direct combustion. Combined heat and power (CHP) or cogeneration systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity. 

Biochemical processes, like anaerobic digestion, can also produce clean energy in the form of biogas which can be converted to power and heat using a gas engine. In addition, wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels. Cellulosic ethanol can be produced from grasses, wood chips and agricultural residues by biochemical route using heat, pressure, chemicals and enzymes to unlock the sugars in biomass wastes. 

Conclusions

Waste-to-energy systems offer two important benefits of environmentally safe waste management and disposal, as well as the generation of clean electric power in the Middle East. Waste-to-energy is not only a solution to reduce the volume of waste that is and provide a supplemental energy source, but also yields a number of social benefits that cannot easily be quantified. The use of waste-to-energy as a method to dispose of solid and liquid wastes and generate power can significantly reduce environmental impacts of municipal solid waste management in the Middle East. 

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Waste-to-Energy Pathways

Waste-to-energy is the use of modern combustion and biological technologies to recover energy from urban wastes. The conversion of waste material to energy can proceed along three major 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. On the other hand, biochemical technologies are more suitable for wet wastes which are rich in organic matter.

Thermochemical Conversion

The three principal methods of thermochemical conversion are combustion (in excess air), gasification (in reduced air), and pyrolysis (in absence of air). The most common technique for producing both heat and electrical energy from wastes is direct combustion. Combined heat and power (CHP) or cogeneration systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity.

Combustion 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. Plasma gasification, which takes place at extremely high temperature, is also hogging limelight nowadays.

Biochemical Conversion

Biochemical processes, like anaerobic digestion, can also produce clean energy in the form of biogas which can be converted to power and heat using a gas engine. Anaerobic digestion is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas. Anaerobic digestion is a reliable technology for the treatment of wet, organic waste.  Organic waste from various sources is biochemically degraded in highly controlled, oxygen-free conditions circumstances resulting in the production of biogas which can be used to produce both electricity and heat.

In addition, a variety of fuels can be produced from waste resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues. Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking.

Physico-chemical Conversion

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 are then mechanically separated before the waste is compacted and converted into pellets or RDF. 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.

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Fuel Pellets from Solid Wastes

MSW is a poor-quality fuel and its pre-processing is necessary to prepare fuel pellets to improve its consistency, storage and handling characteristics, combustion behaviour and calorific value. Technological improvements are taking place in the realms of advanced source separation, resource recovery and production/utilisation of recovered fuel in both existing and new plants for this purpose. There has been an increase in global interest in the preparation of Refuse Derived Fuel (or RDF) containing a blend of pre-processed MSW with coal suitable for combustion in pulverised coal and fluidised bed boilers.

Pelletization of Urban Wastes

Pelletization of municipal solid waste involves the processes of segregating, crushing, mixing high and low heat value organic waste material and solidifying it to produce fuel pellets or briquettes, also referred to as Refuse Derived Fuel (RDF) or Process Engineered Fuel (PEF) or Solid Recovered Fuel (SRF). The process is essentially a method that condenses the waste or changes its physical form and enriches its organic content through removal of inorganic materials and moisture. The calorific value of RDF pellets can be around 4000 kcal/ kg depending upon the percentage of organic matter in the waste, additives and binder materials used in the process.

The calorific value of raw MSW is around 1000 kcal/kg while that of fuel pellets is 4000 kcal/kg. On an average, about 15–20 tons of fuel pellets can be produced after treatment of 100 tons of raw garbage. Since pelletization enriches the organic content of the waste through removal of inorganic materials and moisture, it can be very effective method for preparing an enriched fuel feed for other thermo-chemical processes like pyrolysis/ gasification, apart from incineration.

Pellets can be used for heating plant boilers and for the generation of electricity. They can also act as a good substitute for coal and wood for domestic and industrial purposes. The important applications of RDF in the Middle East are found in the following spheres:

  • Cement kilns
  • RDF power plants
  • Coal-fired power plants
  • Industrial steam/heat boilers
  • Pellet stoves

The conversion of solid waste into briquettes provides an alternative means for environmentally safe disposal of garbage which is currently disposed off in non-sanitary landfills. In addition, the pelletization technology provides yet another source of renewable energy, similar to that of biomass, wind, solar and geothermal energy. The emission characteristics of RDF are superior compared to that of coal with fewer emissions of pollutants like NOx, SOx, CO and CO2.

RDF production line consists of several unit operations in series in order to separate unwanted components and condition the combustible matter to obtain the required characteristics. The main unit operations are screening, shredding, size reduction, classification, separation either metal, glass or wet organic materials, drying and densification. These unit operations can be arranged in different sequences depending on raw MSW composition and the required RDF quality.

Various qualities of fuel pellets can be produced, depending on the needs of the user or market. A high quality of RDF would possess a higher value for the heating value, and lower values for moisture and ash contents. The quality of RDF is sufficient to warrant its consideration as a preferred type of fuel when solid waste is being considered for co-firing with coal or for firing alone in a boiler designed originally for firing coal.

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Waste-to-Energy in Jordan: Potential and Challenges

landfill-jordanEffective sustainable solid waste management is of great importance both for people’s health and for environmental protection. In Jordan, insufficient financial resources, growing population, rapid urbanization, inadequate management and lacking of technical skills represent a serious environmental challenge confronting local government. At the same time, energy remains Jordan’s top challenge for development. The energy needs to be produced in a sustainable way, preferably from renewable sources which have a minimum environmental impact. To face the future problems in waste management, as well as securing the demand of renewable energy, it is necessary to reuse the wasted resources in energy production.

Jordan has definitely acknowledged that making affordable energy solutions available is critical to support industries, investment, and attain sustainable growth. One option is to use solid waste to generate electricity in centralized plants. Waste-to-energy has been recognized as an effective approach to improve recycling rates, reduce the dependence on fossil fuels, reduce the amount of materials sent to landfills and to avoid pollution.

Waste-to-Energy Potential

According to recent statistics, Jordan population stands at around 9.5 million. The estimated municipal waste generated according to the last five years average production is around 3,086,075 ton/year. This huge amount of waste generated is not only a burden, but a potential resource for use in energy production. Considering the country average waste composition 40% is organic waste e.g. avoidable and unavoidable food waste (1,200,000 ton), 10 % are recyclable e.g. paper, plastic, glass, ferrous metals and aluminum (300,000 ton) and 50% are suitable for incineration e.g. garden and park waste, wood and textiles (1,500,000 ton) with high calorific value and energy potential (8.1 MJ/Kg) that is capable to produce electricity 340 kWh/ton waste. The high organic waste is suitable for methane gas capture technologies which is estimated at 170 m3/ton waste.

Technology Options

Nowadays, there are many technologies available which makes it possible to utilize these energy potentials. The major alternatives conventional technologies for large scale waste management are incineration, landfilling and anaerobic digestion. These technologies are affordable, economical visible and associated with minimum environmental impact. The production of electricity is combined with greenhouse gas (GHG) emissions, according to the current energy situation (90% of the country energy produced from fossil fuel), the country emission factor is around 819 CO2-eq/kWh. However, the use of waste to energy solutions is considered to be a clean and definitely the amount of GHG emitted is a lot less than the gases generated by ordinary practices (open dumping and unsanitary landfills).

Construction of an incineration plant for electricity production is often a profitable system even though the installation cost is high since production of electricity often leads to a large economic gain. Landfill gas utilization avoids the release of untreated landfill gases into the atmosphere, and produces electricity to sell commercially in an environmental friendly manner. However, landfilling is associated with methane production. Methane is a potent GHG, contributing 21 times more to global warming than carbon dioxide.

Anaerobic digestion technology is another option. Anaerobic digestion not only decrease GHGs emission but also it is the best technology for treatment of high organic waste through converting the biodegradable fraction of the waste into high-quality renewable calorific gas. Currently, with the growing use of anaerobic technology for treating waste and wastewater, it is expected to become more economically competitive because of its enormous advantages e.g. reduction of pathogens, deactivation of weed seeds and production of sanitized compost.

alghabawi-landfill-jordan

Sorting at the place of generation and recycling e.g. paper, plastic, glass and metals needed to be practiced at the country level or at least where these technologies implemented. Incinerated waste containing plastics (not sorted) releases carbon dioxide, toxic substances and heavy metals to the atmosphere and contributes thereby to climate change and to global warming.

Challenges to Overcome

Waste-to-energy technologies offer enormous potentials as a renewable energy sources and to mitigate climate change in Joran. However, these technologies pose many challenges to the country and discussion makers. Currently, the waste sector is administrated by the government. Poor regulation and insufficient financial resources are limiting the available options toward adapting these new technologies. Private investments and collaboration with the private sector is the key solution in this regard.

Environmental Best Practices for MENA Cement Industry

Cement production in MENA region has almost tripled during the last 15 years, mainly on account of high population growth rate, rapid urbanization, increasing industrialization and large-scale infrastructural development. The growth of cement industry in MENA is marked by factors that are directly connected with sustainability, energy efficiency and raw material supply. Although the factors differ from country to country and cannot be generalized, there are major concerns regarding shortage of raw materials, GHG emissions, dependence on fossil fuels and lack of investment in technological innovations.

For the MENA cement sector, key points for an environment-friendly industry are use of alternative raw materials and alternative fuels, energy-efficient equipment and green technologies. As the use of alternative fuels and raw materials is still uncommon in the Middle East, guidelines and regulatory framework have to be defined which can set standards for the use of alternative or waste-derived fuels like municipal solid wastes, dried sewage sludge, agricultural wastes, drilling wastes etc.

Sewage Sludge

An attractive disposal method for sewage sludge is to use it as alternative fuel source in a cement kiln. Dried sewage sludge with high organic content possesses a high calorific value. Due to the high temperature in the kiln the organic content of the sewage sludge will be completely destroyed. The resultant ash is incorporated in the cement matrix. Infact, several European countries, like Germany and Switzerland, have already started adopting this practice for sewage sludge management.

The MENA region produces huge quantity of municipal wastewater which represents a serious problem due to its high treatment costs and risk to environment, human health and marine life. Sewage generation across the region is rising by an astonishing rate of 25 percent every year. Municipal wastewater treatment plants in MENA produce large amounts of sludge whose disposal is a cause of major concern.

For example, Kuwait has 6 wastewater treatment plants, with combined capacity of treating 12,000m³ of municipal wastewater per day, which produce around 250 tons of sludge daily. Similarly Tunisia has approximately 125 wastewater treatment plants which generate around 1 million tons of sewage sludge every year. Currently most of the sewage is sent to landfills. Sewage sludge generation is bound to increase at rapid rates in MENA due to increase in number and size of urban habitats and growing industrialization.

The use of sewage sludge as alternative fuel is a common practice in cement plants around the world, Europe in particular. It could be an attractive business proposition for wastewater treatment plant operators and cement industry in the Middle East to work together to tackle the problem of sewage sludge disposal, and high energy requirements and GHGs emissions from the cement industry.

Use of sludge in cement kilns will led to eco-friendly disposal of municipal sewage

Use of sludge in cement kilns will led to eco-friendly disposal of municipal sewage

Sewage sludge has relatively high net calorific value of 10-20 MJ/kg as well as lower carbon dioxide emissions factor compared to coal when treated in a cement kiln. Use of sludge in cement kilns can also tackle the problem of safe and eco-friendly disposal of sewage sludge. The cement industry accounts for almost 5 percent of anthropogenic CO2 emissions worldwide. Treating municipal wastes in cement kilns can reduce industry’s reliance on fossil fuels and decrease greenhouse gas emissions.

Municipal Solid Wastes and Biomass

Alternative fuels, such as refuse-derived fuels or RDF, have very good energy-saving potential. The substitution of fossil fuel by alternative sources of energy is common practice in the European cement industry. The German cement industry, for example, substitutes approximately 61% of their fossil fuel demand. Typical alternative fuels available in MENA countries are municipal solid wastes, agro-industrial wastes, industrial wastes and crop residues.

The gross urban waste generation quantity from Middle East countries has crossed 150 million tons per annum. Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita solid waste generation. Solid waste disposal is a big challenge in almost all MENA countries so conversion of MSW to RDF will not ease the environmental situation but also provide an attractive fuel for the regional cement industry. Tens of millions of tyres are discarded across the MENA region each year. Scrap tyres are are an attractive source of energy and find widespread use in countries around the world.

Agriculture plays an important role in the economies of most of the countries in the Middle East and North Africa region.  Despite the fact that MENA is the most water-scarce and dry region in the world, many countries in the region, especially those around the Mediterranean Sea, are highly dependent on agriculture. Egypt is the 14th biggest rice producer in the world and the 8th biggest cotton producer in the world. Similarly Tunisia is one of the biggest producers and exporters of olive oil in the world. Such high biomass production rates should be welcomed by the cement industry since these materials comprise cotton stalks, rice husks and rice straw which serve ideally as alternative fuels. However it is ironical that olive kernels – the waste from Tunisian olive production – is exported to European power plants in order to save fossil fuel-derived CO2 emissions there, while Tunisia imports approximately 90% of its energy demand, consisting of fossil fuels.

Drilling Wastes as Alternative Raw Material

The reduction of clinker portion in cement affords another route to reduce energy consumption. In particular, granulated blast furnace slags or even limestone have proven themselves as substitutes in cement production, thus reducing the overall energy consumption. The Middle East oil and gas industry has made a lot of effort in order to reduce the environmental impact of their activities. The use of drilling wastes and muds is preferable in cement kilns, as a cement kiln can be an attractive, less expensive alternative to a rotary kiln. In cement kilns, drilling wastes with oily components can be used in a fuel-blending program to substitute for fuel that would otherwise be needed to fire the kiln.

Conclusions

The cement industry can play a significant role in the sustainable development in the Arab countries, e.g. by reducing fossil fuel emissions with the use of refused derived fuels (RDF) made from municipal solid waste or biomass pellets. The cement companies in the Middle East can contribute to sustainability also by improving their own internal practices such as improving energy efficiency and implementing recycling programs. Businesses can show commitments to sustainability through voluntary adopting the concepts of social and environmental responsibilities, implementing cleaner production practices, and accepting extended responsibilities for their products.  

The major points of consideration are types of wastes and alternative fuels that may be used, standards for production of waste-derived fuels, emission standards and control mechanisms, permitting procedures etc. Appropriate standards also need to be established for alternative raw materials that are to be used for clinker and cement production.

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Waste-to-Energy Outlook for the Middle East

The high rate of population growth, urbanization and economic expansion in the Middle East is not only accelerating consumption rates but also increasing the generation rate of all sorts of waste. High-income Middle Eastern countries like Saudi Arabia, UAE, Qatar, Bahrain and Kuwait are counted as world’s largest waste producers in terms of per capita waste generation which is more than 2kg per day in some countries. The urban waste generation from the region has now crossed 150 million tons per year which has forced policy-makers and urban planners to look for sustainable waste management solutions, including recycling and waste-to-energy.

Let us take a look at solid waste generation in major countries across the Middle East region:

Country

MSW Generation

(million tons per annum)

Saudi Arabia

15

United Arab Emirates

6

Qatar

2.5

Kuwait

2

Bahrain

1.5

Egypt

20

Tunisia

2.3

Morocco

5

Lebanon

1.6

Jordan

2

In addition, huge quantity of sewage sludge is also generated in the Middle East which presents a serious problem due to its high treatment costs and risk to environment and human health. On an average, the rate of wastewater generation is 80-200 litres per person each day and sewage output is rising by 25 percent every year across the region.

Conversion Pathways

Municipal solid waste is a very good source of biomass in the Middle East. Municipal solid waste is comprised of organic fraction, paper, glass, plastics, metals, wood etc. Almost 50% of the solid waste is contributed by organic matter.

Municipal solid waste can be converted into energy by conventional technologies (such as incineration, mass-burn and landfill gas capture). Municipal solid waste can also be efficiently converted into energy and fuels by advanced thermal technologies, such as gasification and pyrolysis.

At the landfill sites, the gas produced by the natural decomposition of MSW is collected from the stored material and scrubbed and cleaned before feeding into internal combustion engines or gas turbines to generate heat and power. In addition, the organic fraction of MSW can be anaerobically stabilized in a high-rate digester to obtain biogas for electricity or steam generation.

Anaerobic digestion is the most preferred option to extract energy from sewage, which leads to production of biogas and organic fertilizer. The sewage sludge that remains can be incinerated or gasified/pyrolyzed to produce more energy. In addition, sewage-to-energy processes also facilitate water recycling.

Relevance for Middle East

The variety of technological options available means that waste-to-energy can be applied at a small, localized scale primarily for heat, or it can be used in much larger base-load power generation capacity whilst also producing heat. Waste-to-energy conversion can thus be tailored to rural or urban environments in the Middle East, and utilized in domestic, commercial or industrial applications in the entire region.

The world’s dependence on Middle East energy resources has caused the region to have some of the largest carbon footprints per capita worldwide. The GCC region is now gearing up to meet the challenge of global warming, as with the rapid growth of the waste management sector. During the last few years, UAE, Qatar and Saudi Arabia have unveiled multi-billion dollar investment plans to Improve waste management scenario. In particular, the establishment of Domestic Solid Waste Management Centre in Qatar has catalyzed public interest in deployment of waste-to-energy systems in the Middle East.

Energy recovery from MSW is rapidly gaining worldwide recognition as the fourth ‘R’ in sustainable waste management system – Reuse, Reduce, Recycle and Recover. A transition from conventional waste management system to one based on sustainable practices is necessary to address environmental concerns and to foster sustainable development in the region.

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Wastes as Energy Resource

The tremendous increase in the quantum and diversity of waste materials generated by human activities has focused the spotlight on waste management options. Waste generation rates are affected by standards of living, degree of industrialization and population density. Generally, the greater the economic prosperity and the higher percentage of urban population, the greater the amount of waste produced. A good example are the oil-rich GCC nations who are counted among the world's most prolific per capita waste generators.

Reduction in the volume and mass of wastes is a crucial issue due to limited availability of final disposal sites in the Middle East. There is, no doubt, an obvious need to reduce, reuse and recycle wastes but recovery of energy from wastes is also gaining ground as a vital method for managing wastes and Middle East should not be an exception.

Wastes can be transformed into clean and efficient energy and fuel by a variety of technologies, ranging from conventional combustion process to state-of-the-art plasma gasification technology. Besides recovery of energy, such technologies leads to substantial reduction in the overall waste quantities requiring final disposal. Waste-to-energy projects provide major business opportunities, environmental benefits, and energy security.  Feedstock for waste-to-energy plants can be obtained from a wide array of sources including municipal wastes, crop residues and agro-industrial wastes. 

Let us explore some of major waste resources that are readily available in Middle East and North Africa region:

Municipal Solid Wastes

Atleast 150 million tons of solid wastes are collected each year in the MENA region with the vast majority disposed of in open fields and dumpsites. The major energy resource in municipal solid waste is made up of food residuals, paper, fruits, vegetables, plastics etc which make up as much as 75 – 80 percent of the total MSW collected.

Municipal wastes can be converted into energy by thermochemical or biological technologies. At the landfill sites the gas produced by the natural decomposition of MSW (called landfill gas) can be collected, scrubbed and cleaned before feeding into internal combustion engines or gas turbines to generate heat and power. The organic fraction of MSW can be biochemically stabilized in an anaerobic digester to obtain biogas (for heat and power) as well as fertilizer. Sewage sludge is a big nuisance for municipalities and general public but it is a very good source of biogas, which can efficiency produced at sewage treatment plants.

Agricultural Residues

Crop residues encompasses all agricultural wastes such as bagasse, straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. Large quantities of crop residues are produced annually in the MENA region, and are vastly underutilised. Wheat and barley are the major staple crops grown in the Middle East region. In addition, significant quantities of rice, maize, lentils, chickpeas, vegetables and fruits are produced throughout the region, mainly in Egypt, Tunisia, Saudi Arabia, Morocco and Jordan. 

Current farming practice is usually to plough these residues back into the soil, or they are burnt, left to decompose, or grazed by cattle. Agricultural residues are characterized by seasonal availability and have characteristics that differ from other solid fuels such as wood, charcoal, char briquette. Crop wastes can be used to produce biofuels, biogas as well as heat and power through a wide range of well-proven technologies.

Animal Wastes

The MENA countries have strong animal population. The livestock sector, in particular sheep, goats and camels, plays an important role in the national economy of respective countries. Many millions of live ruminants are imported each year from around the world. In addition, the region has witnessed very rapid growth in the poultry sector.

The biogas potential of animal manure can be harnessed both at small- and community-scale. In the past, this waste was recovered and sold as a fertilizer or simply spread onto agricultural land, but the introduction of tighter environmental controls on odour and water pollution means that some form of waste management is now required, which provides further incentives for waste-to-energy conversion. The most attractive method of converting these waste materials to useful form is anaerobic digestion.

Wood Wastes

Wood processing industries primarily include sawmilling, plywood, wood panel, furniture, building component, flooring, particle board, moulding, jointing and craft industries. Wood wastes generally are concentrated at the processing factories, e.g. plywood mills and sawmills. In general, processing of 1,000 kg of wood in the furniture industries will lead to waste generation of almost half (45 %), i.e. 450 kg of wood.

Similarly, when processing 1,000 kg of wood in sawmill, the waste will amount to more than half (52 %), i.e. 520 kg wood. Wood wastes has high calorific value and can be efficiency converted into energy by thermal technologies like combustion and gasification.

Industrial Wastes

The food processing industry in MENA produces a large number of organic residues and by-products that can be used as biomass energy sources. These waste materials are generated from all sectors of the food industry with everything from meat production to confectionery producing waste that can be utilised as an energy source. In recent decades, the fast-growing food and beverage processing industry has remarkably increased in importance in major countries of the region.

Since the early 1990s, the increased agricultural output stimulated an increase in fruit and vegetable canning as well as juice, beverage, and oil processing in countries like Egypt, Syria, Lebanon and Saudi Arabia. Wastewater from food processing industries contains sugars, starches and other dissolved and solid organic matter. A huge potential exists for these industrial wastes to be biochemically digested to produce biogas, or fermented to produce ethanol, and several commercial examples of waste-to-energy conversion already exist around the world.

Conclusions

An environmentally sound and techno-economically viable methodology to treat wastes is highly crucial for the sustainability of modern societies. The MENA region is well-poised for waste-to-energy development, with its rich resources in the form of municipal solid waste, crop residues and agro-industrial waste. The implementation of advanced waste-to-energy conversion technologies as a method for safe disposal of solid and liquid wastes, and as an attractive option to generate heat, power and fuels, can greatly reduce environmental impacts of wastes in the Middle East. 

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Insights into WTE Industry

Waste-to-Energy is the use of modern combustion and biochemical technologies to recover energy, usually in the form of electricity and steam, from urban wastes. These new technologies can reduce the volume of the original waste by 90%, depending upon composition and use of outputs. The main categories of waste-to-energy technologies are physical technologies, which process waste to make it more useful as fuel; thermal technologies, which can yield heat, fuel oil, or syngas from both organic and inorganic wastes; and biological technologies, in which bacterial fermentation is used to digest organic wastes to yield fuel.

Global Scenario

Around 130 million tonnes of municipal solid waste (MSW) are combusted annually in over 600 waste-to-energy (WTE) facilities globally that produce electricity and steam for district heating and recovered metals for recycling. Since 1995, the global WTE industry increased by more than 16 million tonnes of MSW. Incineration, with energy recovery, is the most common waste-to-energy method employed worldwide. Over the last five years, waste incineration in Europe has generated between an average of 4% to 8% of their countries’ electricity and between an average of 10% to 15% of the continent’s domestic heat.

Currently, the European nations are recognized as global leaders of the SWM and WTE movement. They are followed behind by the Asia Pacific region and North America respectively. In 2007 there are more than 600 WTE plants in 35 different countries, including large countries such as China and small ones such as Bermuda. Some of the newest plants are located in Asia.

The United States processes 14 percent of its trash in WTE plants. Denmark, on the other hand, processes more than any other country – 54 percent of its waste materials. As at the end of 2008, Europe had more than 475 WTE plants across its regions – more than any other continent in the world – that processes an average of 59 million tonnes of waste per annum. In the same year, the European WTE industry as a whole had generated revenues of approximately US$4.5bn.

Legislative shifts by European governments have seen considerable progress made in the region’s WTE industry as well as in the implementation of advanced technology and innovative recycling solutions. The most important piece of WTE legislation pertaining to the region has been the European Union’s Landfill Directive, which was officially implemented in 2001 which has resulted in the planning and commissioning of an increasing number of WTE plants over the past five years.

Middle East Scenario

Unfortunately, Middle East is yet to witness real activity in waste-to-energy sector. There has been several promising initiatives in the past few years, especially in Qatar, UAE and Jordan but more efforts are required to make waste-to-energy a byline for sustainable development. The Middle East is well-poised for waste-to-energy development, with its rich feedstock base in the form of municipal solid wastes.

The high rate of population growth, urbanization and economic expansion in the Middle East is not only accelerating consumption rates but also accelerating the generation of solid waste. Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita waste generation. The gross urban waste generation quantity from Middle East countries is estimated at more than 150 million tons annually which could be better managed if waste-to-energy is incorporated in the solid waste management strategy in Middle Eastern countries.

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استخراج الوقود من النفايات – وسيلة لتحويل القمامة إلى كنز

لقد أدى ارتفاع معدل النمو السكاني والتوسع العمراني والازدهار الاقتصادي في الشرق الأوسط إلى تسريع معدلات الاستهلاك وزيادة معدل إنتاج النفايات بجميع أنواع؛ حيث تحتل كل من البحرين والسعودية والإمارات العربية المتحدة وقطر والكويت المراتب العشر الأولى في العالم من حيث نصيب الفرد من توليد النفايات الصلبة. وقد تعدت كمية توليد النفايات الصلبة الإجمالية في دول الشرق الأوسط 150 مليون طن سنوياً. أصبح خفض حجم وكتلة النفايات قضية حاسمة نظراً لمحدودية توفر مواقع التخلص من النفايات. هنالك، ولا شك، حاجة واضحة للحد وإعادة استخدام وإعادة تدوير النفايات، ولكن في اللآونة الأخيرة، بدأت عملية تحويل النفايات إلى وقود تكتسب أهمية كوسيلة بديلة لإدارة النفايات.

يتم التخلص من الغالبية العظمى من النفايات في الحقول المفتوحة والمكبات التي  تتسبب في انبعاث غاز الميثان والذي يساهم في ظاهرة الدفيئة العالمية، حيث أن أثر كل طن واحد من الميثان يساوي عشرين ضعف أثر طن واحد من ثاني أكسيد الكربون. فلذلك تتجه الدول إلى تقليص المكبات وإعادة استخدام جميع النفايات بطريقة أو بأخرى، منها التدوير والوقد والزبل العضوي بحيث لا يتبقى شيء لملء المكبات.

يعتقد العديد أن الممارسة الأفضل في استخدام الوقود أو الغاز هو إنتاج الكهرباء، ولكن ذلك غير صحيح لأن إنتاج الكهرباء عادة ما يتم بكفاءة  40-50% و يعتبرالباقي فاقداً حرارياً. أما الفائدة الكبرى هي في استخدامات الوقود المشتق من النفايات، والذي يمكن حرقه بطريقة بيئية حيث يتم استغلال جميع السعرات الحرارية  بأفضل كفاءة ممكنة.

يستخدم الوقود المشتق من النفايات في مصدر المنشأ لأنه متاح بسهولة ليتم استعماله في تغطية احتياجات الحرارة والطاقة. ويستمد معظم هذا الوقود من عملية الإنتاج في الموقع ويستخدم بتكلفة قليلة أو معدومة، وبذلك يخفض تكاليف الوقود الإجمالية حيث أنه يستبدل الوقود الأحفوري. يقلل استعمال وقود النفايات الصلبة أيضاً من حجم النفايات اللازم التخلص منها، ويخفض من تكلفة التخلص على المصنعين.

 تستخدم صناعات الخشب والورق والمواد الكيميائية والنفط ومنتجات الفحم والبلاستيك والإسمنت كلها الوقود المستخرج من النفايات، بما فيها الزيوت والقطران ونفايات الورق، وأي شيء آخر يمكن استخدامه لتوفير الحرارة والكهرباء في المنشأة الصناعية. على سبيل المثال، يستخدم في صناعة الأسمنت مجموعة متنوعة من النفايات لتوفير الحرارة للأفران، بما في ذلك الإطارات القديمة، والنفايات البلدية الصلبة، والأقمشة الخردة، والدهانات، والأحبار، والمواد المتعارف عليها بـ RDF.Refuse Derived Fuel وقود (RDF) هو الوقود الذي ينتج عن عملية تمزيق وتجفيف النفايات الصلبة، ويتكون إلى حد كبير من مكونات قابلة للاحتراق مثل البلاستيك والنفايات القابلة للتحلل.

أما بالنسبة للنفايات البلاستيكية، فإنها تشكل تحدياً بيئياً هاماً في الشرق الأوسط، حيث أنها في تزايد مستمر بسبب استخدامها في شتى مجالات الحياة واعتمادنا عليها اعتماداً كلياً في الصتاعات المختلفة وتكنولوجياتها الحديثة المتقدمة. إن منطقة الشرق الأوسط مسؤولة عن حوالي 8% من الإنتاج العالمي من البلاستيك، علماً بأنه يتم تدوير حوالي 25% فقط من إجمالي كمية نفايات المواد البلاستيكية عالمياً. ومن الجدير بالذكر أن بعض النفايات البلاستيكية لا ينتهي بها الأمر في المكبات، بل تجد طريقها إلى الشواطئ والبحار حيث تلحق أضراراً جسيمة  بالحياة البحرية.

نظراً للاهتمام العالمي المتزايد بالبيئة ، لقد لجأ كثير من الباحثين في مختلف دول العالم إلى تحويل النفايات البلاستيكية إلى زيت بترول مرة أخرى، واستخراج الجازولين والكيروسين والزيوت البترولية منه واستعمالها كوقود لإدارة المحركات، وذلك من خلال عمليات التحلل الحراري للنفايات البلاستيكية. ولقد اهتمت اليابان بتلك التقنية، وكذلك الهند، والصين، وكوريا، ودول شمال شرق آسيا.

لم يعد تخليص العالم من النفايات ضرباً من ضروب الخيال، فبفضل تطور البحث العلمي والتكنولوجيات، أصبح بإمكاننا الاستفادة من النفايات بدلاً من التخلص منها في المكبات التي ما زالت في توسع مستمر. ونظراً لتمتع منطقة الشرق الأوسط بموارد غنية من الكتلة الحيوية والتي تتضمن النفايات البلدية الصلبة ومخلفات المحاصيل والنفايات الزراعية والصناعية، فإنها تشكل سوقاً محتملاً لتحويل النفايات إلى وقود. إن المواد التي كانت تعتبر قمامة لا تزال توفر ما بعد انتهاء عمرها المفيد موارد طاقة قيمة، قادرة على حل مشاكل متعددة في آن واحد، فمن كان يعلم أن القمامة يمكن أن تتحول إلى كنز؟

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A Primer on Landfill Gas Recovery

Landfill gas (or LFG) is generated during the natural process of bacterial decomposition of organic material contained in municipal solid waste landfills or garbage dumps. The waste is covered and compressed mechanically as well as by the weight of the material that is deposited above. This material prevents oxygen from accessing the waste thus producing ideal conditions for anaerobic microorganism to flourish. This gas builds up and is slowly released into the atmosphere if the landfill site has not been engineered to capture the gas.

The rate of production is affected by waste composition and landfill geometry, which in turn influence the bacterial populations within it, chemical make-up, thermal range of physical conditions and biological ecosystems co-existing simultaneously within most sites. This heterogeneity, together with the frequently unclear nature of the contents, makes landfill gas production more difficult to predict and control.

Composition of Landfill Gas

Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Landfill gas also contains varying amounts of nitrogen, oxygen, water vapour, hydrogen sulphide, and other contaminants. Most of these other contaminants are known as “non-methane organic compounds” or NMOCs. Some inorganic contaminants (for example mercury) are also known to be present in landfill gas. There are sometimes also contaminants (for example tritium) found in landfill gas. The non-methane organic compounds usually make up less than one percent of landfill gas.

Hazards of Landfill Gas

This gas starts creating pressure within the surface of earth when no exit route is present. Excessive pressure leads to sudden explosion that can cause serious harm to people living in the surrounding areas. Due to the constant production of landfill gas, the increase in pressure within the landfill (together with differential diffusion) causes the gas’s release into the atmosphere. Such emissions lead to important environmental, hygiene and security problems in the landfill.

Accidents due to landfill gas explosions are not uncommon around the world. For example a mishap took place at Loscoe, England in 1986, where migrating landfill gas, which was allowed to build up, partially destroyed the property. Landfills in the Middle East are notorious for spontaneous fires and toxic emissions. Due to the risk presented by landfill gas there is a clear need to monitor gas produced by landfills. In addition to the risk of fire and explosion, gas migration in the subsurface can result in contact of landfill gas with groundwater. This, in turn, can result in contamination of groundwater by organic compounds present in nearly all landfill gas.

Treatment of Landfill Gas

Depending on the end use, landfill gas must be treated to remove impurities, condensate, and particulates. Minimal treatment is needed for the direct use of gas in boiler, furnaces, or kilns. Using the gas in electricity generation typically requires more in-depth treatment. Primary processing systems remove moisture and particulates. Gas cooling and compression are common in primary processing. Secondary treatment systems employ multiple cleanup processes, physical and chemical, depending on the specifications of the end use.

Uses of Landfill Gas

Landfill gas can be converted to high calorific value gas by reducing its carbon dioxide, nitrogen, and oxygen content which can be piped into existing natural gas pipelines or in the form of CNG (compressed natural gas) or LNG (liquid natural gas). CNG and LNG can be used on site to power hauling trucks or equipment or sold commercially. The gas can also be used for combined heat and power generation or industrial heating purposes. For example, the City of Sioux Falls in South Dakota installed a landfill gas collection system which collects, cools, dries, and compresses the gas into an 11-mile pipeline. The gas is then used to power an ethanol plant operated.

Landfill Gas Recovery Projects in Middle East

The number of landfill gas projects, which convert the methane gas that is emitted from decomposing garbage into power, has seen significant increase around the world, including the Middle East. These projects are popular because they control energy costs and reduce greenhouse gas emissions. Landfill gas recovery projects collect and treat the methane gas, so it can be used for electricity or upgraded to pipeline-grade quality to power homes, buildings, and vehicles.

Dubai Municipality has commissioned the region's largest landfill gas recovery system at its Al Qusais Landfill site. The Al Qusais Landfill is one of the largest sites for municipal waste collection in Dubai receiving about 5,000 tons daily. Construction work for the landfill gas project involved drilling of horizontal and vertical gas wells 22 metres deep into the waste to extract the landfill gas.

The Government of Jordan, in collaboration with UNDP, GEF and the Danish Government, established 1MW landfill gas recovery cum biogas plant at Rusaifeh landfill near Amman in 1999.  The project consists of a system of twelve landfill gas wells and an anaerobic digestion plant based on 60 tons per day of organic wastes from hotels, restaurants and slaughterhouses in Amman. 

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Use of Sewage Sludge in Cement Industry

The MENA region produces huge quantity of municipal wastewater which represents a serious problem due to its high treatment costs and risk to environment, human health and marine life. The per capita wastewater generation rate in the region is estimated at 80-200 litres per day. Sewage generation across the region is rising by an astonishing rate of 25 percent every year.

Municipal wastewater treatment plants in MENA produce large amounts of sludge whose disposal is a cause of major concern. For example, Kuwait has 6 wastewater treatment plants, with combined capacity of treating 12,000m³ of municipal wastewater per day, which produce around 250 tons of sludge daily. Similarly Tunisia has approximately 125 wastewater treatment plants which generate around 1 million tons of sewage sludge every year. Currently most of the sewage is sent to landfills. Sewage sludge generation is bound to increase at rapid rates in MENA due to increase in number and size of urban habitats and growing industrialization.

Use of Sewage Sludge in Cement Industry

An attractive disposal method for sewage sludge is to use it as alternative fuel source in a cement kiln. The resultant ash is incorporated in the cement matrix. Infact, several European countries, like Germany and Switzerland, have already started adopting this practice for sewage sludge management. Sewage sludge has relatively high net calorific value of 10-20 MJ/kg as well as lower carbon dioxide emissions factor compared to coal when treated in a cement kiln. Use of sludge in cement kilns can also tackle the problem of safe and eco-friendly disposal of sewage sludge. The cement industry accounts for almost 5 percent of anthropogenic CO2 emissions worldwide. Treating municipal wastes in cement kilns can reduce industry’s reliance on fossil fuels and decrease greenhouse gas emissions.

The use of sewage sludge as alternative fuel in clinker production is one of the most sustainable option for sludge waste management. Due to the high temperature in the kiln the organic content of the sewage sludge will be completely destroyed. The sludge minerals will be bound in the clinker after the burning process. The calorific value of sewage sludge depends on the organic content and on the moisture content of the sludge. Dried sewage sludge with high organic content possesses a high calorific value.  Waste coming out of sewage sludge treatment processes has a minor role as raw material substitute, due to their chemical composition.

The dried municipal sewage sludge has organic material content (ca. 40 – 45 wt %), therefore the use of this alternative fuel in clinker production will save fossil CO2 emissions. According to IPCC default of solid biomass fuel, the dried sewage sludge CO2 emission factor is 110 kg CO2/GJ without consideration of biogenic content. The usage of municipal sewage sludge as fuel supports the saving of fossil fuel emission.

Sludge is usually treated before disposal to reduce water content, fermentation propensity and pathogens by making use of treatment processes like thickening, dewatering, stabilisation, disinfection and thermal drying. The sludge may undergo one or several treatments resulting in a dry solid alternative fuel of a low to medium energy content that can be used in cement industry.

Conclusions

The use of sewage sludge as alternative fuel is a common practice in cement plants around the world, Europe in particular. It could be an attractive business proposition for wastewater treatment plant operators and cement industry in the Middle East to work together to tackle the problem of sewage sludge disposal, and high energy requirements and GHGs emissions from the cement industry.

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