Bioenergy Resources in Jordan

 

With high population growth rate, increase in industrial and commercial activities, high cost of imported energy fuels and higher GHGs emissions, supply of cheap and clean energy resources has become a challenge for the Jordanian Government. Consequently, the need for implementing renewable energy projects, especially solar, wind and biomass, has emerged as a national priority in recent years.

Jordan has substantial biomass resources in the form of municipal solid wastes, sewage, industrial wastes and animal manure. Municipal solid wastes represent the best source of biomass in Jordan. Solid waste generation in the country is approximately 2 million tons per annum, with per capita of almost 1 kg per day. The daily waste generation exceeds 6,000 tons which is characterized by high organic content (more than 50 percent). Food waste constitutes almost 60% of the total waste at most disposal sites. In addition, more than 2 million cubic meter of sewage sludge is generated every year from treatment of sewage water in Greater Amman area which could be a very good source for biogas generation.

Apart from MSW, the other potential biomass resources in the country are as follows:

  • Organic wastes from slaughterhouse, vegetable market, hotels and restaurants.
  • Organic waste from agro-industries
  • Animal manure, mainly from cows and chickens.
  • Olive mills.
  • Organic industrial waste

Organic industrial wastes, either liquid or solid, are a good substrate for biogas generation by making use of anaerobic digestion process. Anaerobic digestion of organic industrial waste is fast gaining popularity worldwide as one of the best waste management method. The utilization of anaerobic digestion technology for industrial waste management would be a significant step in Jordan’s emergence as a renewable energy hub in the MENA region. Jordan is planning to implement 40-50 MW of waste-to-energy projects by 2020.

Biogas Plant at Rusaifeh Landfill

The Government of Jordan, in collaboration with UNDP, GEF and the Danish Government, established 1MW biogas plant at Rusaifeh landfill near Amman in 1999.  The plant has been successfully operating since its commissioning and has recently been increased to 4MW. 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. The successful installation of the biogas project has made it a role model in the entire region and several big cities are striving to replicate the model.

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Animal Waste Management in Africa

Livestock and poultry production are among the main economic activities in rural as well as urban areas of African countries.The livestock sector, in particular sheep, goats and camels, plays an important role in the national economy of African countries. In addition, the region has witnessed very rapid growth in the poultry sector.

However, livestock industry is contributing heavily to greenhouse gas emissions and waste management problems in Africa due to the absence of a sustainable Animal Waste Management System in the region. Most of the manure is collected in lagoons or left to decompose in the open which presents a severe environmental hazard.

The use of anaerobic digestion for animal waste disposal is an attractive way to address environmental problems, especially methane emissions. Anaerobic digestion of livestock manure is an alternative pathway for managing large organic waste loads and its associated problems encountered in large feeding lots and confined animal feeding operations.

Despite the numerous benefits associated with anaerobic digestion as a sustainable waste management strategy, these combined merits have never been quantified in African countries.The biogas potential of animal manure can be harnessed both at small- and community-scale. An essential aspect for adopting anaerobic digestion systems is the development of a methane market that acknowledges role of biogas systems in mitigating climate change.

With the present energy and pollution problem in Africa, conversion of animal manure as source of clean energy as well as organic fertilizer offers a great advantage. Anaerobic digestion technologies can help preserve and integrate livestock production within communities and create renewable energy resources to serve a growing bio-economy within rural communities.

Anaerobic digestion is a controlled biological treatment process that can substantially reduce the impact of livestock and poultry manures on air and water quality. An anaerobic digestion plant produces two outputs, biogas and digestate, both can be further processed or utilised to produce secondary outputs. Biogas can be used for producing electricity and heat, as a natural gas substitute and also a transportation fuel.

A biogas plant is a decentralized energy system, which can lead to self-sufficiency in heat and power needs, and at the same time reduces environmental pollution. The main features of a biogas facility are as follows:

  • Processing of renewable energy source
  • Reduction of malodors
  • Removal of harmful pathogens
  • Reduction of COD & BOD contents of processed waste
  • Production of organic fertilizer for green areas
  • Reduction in emissions of greenhouse gases
  • Production of relatively clean water for flushing or irrigation

Animal manure-to-biogas transformation has enormous potential in reducing greenhouse gas emissions and harnessing the untapped renewable energy potential of animal manure. Biogas can be used as a fuel for internal combustion engines, to generate electricity from small gas turbines, burnt directly for cooking, for space and water heating. or for running vehicles.

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Airports: Viable Places for Green Initiatives

Bahrain-airportCan airports ever be green? This is an overwhelming concept in a carbon-driven, and carbon-intensive industry. The reality is that air travel is often the only realistic option for the movement of both people and cargo in the current lifestyle and demands encompassed with time constraints. This is especially critical for the island nation of Bahrain that is so heavily dependent on air travel in terms of food security. With over 90% of all goods: perishable and manufactured, imported into the nation, this carbon-intensive industry is not going to disappear.

Airports themselves, may only contribute 5% to the carbon emissions attributed to the aviation industry, never the less, airport infrastructure could ensure a lowering of emissions, especially nitrogen oxide levels [1]. The International Air Transportation Association (IATA) has statistical evidence of improved fuel efficiency and better CO2 performance over the past 15 years[1]. It is viable for airports to reduce the nitrogen oxide levels around airports by developing ground transportation infrastructure for transferring passengers and deploying employees across the airport terminals, ground handling of personal baggage and commercial cargo, as well as the catering services, in a more eco-friendly mode of transportation.

Scope for Green Airports

Airports are viable places for adoption of green initiatives. A significant portion of the emissions are from vehicle transportation onsite at the airport is from moving employees and passengers between terminals and aircraft carriers. Plus all the freight movement, personal baggage and inflight catering and servicing. To secure adequate food products for Bahrain, the greater part of all food produce that is available on the market (93%) is flown in on a daily basis. The dependency on aviation is long-term but the ground handling is an option for energy efficient initiatives.

There is an opportunity to move from fossil fuel vehicles to those running on clean such as hybrid, electric, bioethanol, biogas or hydrogen-fueled vehicles. As road transportation is a major contributor of carbon dioxide and nitrogen oxide emissions, greener, cleaner vehicles are a desirable consideration for protecting a fragile environment.

Role of Environmental Awareness

Greater awareness of renewable energy sources is necessary before developers can even start to appeal to the business sector to adopt viable alternatives of transportation energy. New airport development and expansion projects need to assess the feasibility of alternative mode of transportation which in turn will require electrical charging locations as well as hydrogen filling stations [2]. This can also be marketed to eco-friendly rental companies to avail themselves of green initiatives.

Freight and delivery corporation could also avail themselves of alternative power sources as petrol subsides are reduced over the coming years. Ultimately, sustainable energy sources will become more attractive. Together, a sustainable transportation model along with other sustainable life-cycle models will all help reduce the carbon footprint of the airport industry.

Airports are considered ideal sites for promoting electricity-powered vehicles because one has a captive audience. If the options are already determined for the clients, the clients experience the use of electric cars in a win-win situation.

Rapid Increase in Passenger Flow

During the month of November, 2016, almost 674,000 passengers passed through the Bahrain airport [3]. There was over 8,500 total aircraft movement and almost 20,000 pieces of cargo and mail in the 30 day period. (Data source: Ministry of Transportation and Telecommunications). Based on the November data, the numbers could be extrapolated out for a 12-month period with over 8 million passengers per year, over 100,000 total aircraft movement and 240,000 pieces of cargo and mail.

Similar information based on the official Airport Councils International (ACI) statistics from the World Airport Traffic Reports for the 10-year period from 2005 to 2015 [3]. The reports indicate a yearly average of 7.8 million passengers with over 95,350  total aircraft movements and over 304,000 metric tons of cargo. The steady increase in usage of airport facilities [4] is driving the modernization plans for the Bahrain International Airport to be designed for an annual passenger flow of 14 million persons [5].

Heathrow Airport – An Upcoming Role Model

Heathrow Airport in London handles more than 76 million passengers each year. Heathrow is already conducting trials for electric buses and personal electric cars, as part of a sustainable model, which requires a major input for developing recharging infrastructure. Such a large airport in the heart of a metropolitan centre has the advantage of a well developed public transportation infrastructure.

Electric vehicles at Heathrow Aiport

Electric vehicles at Heathrow Aiport

Both travelers and employees use the public transport systems which allows the advanced planning in other sustainable green technology for other transportation systems. Passenger car parks as well as company car parks have charging points for electric cars. The airport strategic plan is to have all cars and vans electric rather than fossil fuel powered by 2020.

Perspectives for Bahrain

Aviation transportation is vital for Bahrain’s survival and daily operations. Therefore, a eco-friendly infrastructure is a viable option for implementing green technology in the form of onsite transportation. However, the modernization of the Bahrain International Airport has limited its eco-friendly inclusion to ground service equipment such as the transformer substations, pre-conditioned air systems and pop-up units and the 400Hz power supply system all contracted to Cavotec Middle East [5].

This is one step towards achieving the International Civil Aviation Organization (ICAO) decision to implement a global carbon offset for the aviation industry. It would be great to see the Ministry of Transportation and Telecommunications reach out to other green initiatives for the modernization of the national airport.

 

References

1. Can airports be green? http://www.airport-technology.com/features/feature100283/

2. How airports uniquely placed to boost the adoption of electric cars. https://www.theguardian.com/heathrow-sustainable-mobility-zone/2016/nov/21/airports-uniquely-placed-boost-adoption-electric-cars-emissions-reduction?CMP=ema-1706&CMP=

3. Airports Council International, World Airport Traffic Reports, 2005, 2006, 2007, 2008, 2009, 2020, 2011, 2012, 2014 and 2015. Traffic by Calendar Year, Official ACI Statistics. https://en.wikipedia.org/wiki/Bahrain_International_Airport

4. Bahrain International Airport witnesses a 25% increase in passenger movement http://www.mtt.gov.bh//press-centre/press-releases/210914

5. New Passenger Terminal Building, Bahrain International Airport, Manama, Bahrain http://www.airport-technology.com/projects/new-passenger-terminal-building-bahrain-international-airport-manama/

Biomass Potential of Date Palm Wastes

Date palm is one of the principal agricultural products in the arid and semi-arid region of the world, especially Middle East and North Africa (MENA) region. There are more than 120 million date palm trees worldwide yielding several million tons of dates per year, apart from secondary products including palm midribs, leaves, stems, fronds and coir. The Arab world has more than 84 million date palm trees with the majority in Egypt, Iraq, Saudi Arabia, Iran, Algeria, Morocco, Tunisia and United Arab Emirates.

Egypt is the world’s largest date producer with annual production of 1.47 million tons of dates in 2012 which accounted for almost one-fifth of global production. Saudi Arabia has more than 23 millions date palm trees, which produce about 1 million tons of dates per year. Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits. Some studies have reported that Saudi Arabia alone generates more than 200,000 tons of date palm biomass each year.

Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in date-producing nations. In countries like Iraq and Egypt, a small portion of palm biomass in used in making animal feed.

The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date palm biomass an excellent waste-to-energy resource in the MENA region. A wide range of thermal and biochemical technologies exists to convert the energy stored in date palm biomass to useful forms of energy. The low moisture content in date palm wastes makes it well-suited to thermo-chemical conversion technologies like combustion, gasification and pyrolysis.

On the other hand, the high volatile solids content in date palm biomass indicates its potential towards biogas production in anaerobic digestion plants, possibly by codigestion with sewage sludge, animal wastes and/and food wastes. The cellulosic content in date palm wastes can be transformed into biofuel (bioethanol) by making use of the fermentation process. Thus, abundance of date palm trees in the GCC, especially Saudi Arabia, can catalyze the development of biomass and biofuels sector 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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Biogas Feedstock in the Middle East

Anaerobic digestion (or biogas technology) is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas. It 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. Almost any organic material can be processed with anaerobic digestion. 

A wide range of organic wastes are available in the Middle East for anaerobic digestion. In addition to MSW, large quantity of waste, in both solid and liquid forms, is generated by the industrial sector like sugar mills, agro=processing, food processing, leather, pharmaceuticals and paper and pulp industries. Poultry waste has the highest biogas potential per ton of waste, however livestock wastes have the greatest potential for energy generation in the agricultural sector.

Here is the list of potential feedstock for biogas production in the Middle East.

Agricultural Feedstock

  • Animal manure
  • Energy crops
  • Algal biomass
  • Crop residues

Community-Based Feedstock

  • Organic fraction of MSW (OFMSW)
  • Sewage sludge
  • Grass clippings/garden waste
  • Food residuals
  • Institutional wastes etc.

Industrial Feedstock

  • Food/beverage processing
  • Dairy
  • Starch industry
  • Sugar industry
  • Pharmaceutical industry
  • Cosmetic industry
  • Biochemical industry
  • Pulp and paper
  • Slaughterhouse/rendering plant etc.

Anaerobic digestion is particularly suited to wet organic material and is commonly used for effluent and sewage treatment. Almost any organic material can be processed with anaerobic digestion. This includes biodegradable waste materials such as waste paper, grass clippings, leftover food, sewage and animal waste. The exception to this is woody wastes that are largely unaffected by digestion as most anaerobic microorganisms are unable to degrade lignin. 

Anaerobic digesters can also be fed with specially grown energy crops such as silage for dedicated biogas production. A wide range of crops, especially C-4 plants, demonstrate good biogas potentials. Corn is one of the most popular co-substrate in Germany while Sudan grass is grown as an energy crop for co-digestion in Austria. Crops like maize, sunflower, grass, beets etc., are finding increasing use in agricultural digesters as co-substrates as well as single substrate.

A wide range of organic substances are anaerobically easily degradable without major pretreatment. Among these are leachates, slops, sludges, oils, fats or whey. Some wastes can form inhibiting metabolites (e.g.NH3) during anaerobic digestion which require higher dilutions with substrates like manure or sewage sludge. A number of other waste materials often require pre-treatment steps (e.g. source separated municipal bio-waste, food leftovers, expired food, market wastes and crop residues).

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Combined Heat and Power Systems

Combined Heat and Power (CHP), or Cogeneration, is the sequential or simultaneous generation of multiple forms of useful energy (usually mechanical and thermal) in a single, integrated system. In conventional electricity generation systems, about 35% of the energy potential contained in the fuel is converted on average into electricity, whilst the rest is lost as waste heat.

CHP systems uses both electricity and heat and therefore can achieve an efficiency of up to 90%, giving energy savings between 15-40% when compared with the separate production of electricity from conventional power stations and of heat from boilers.

CHP systems consist of a number of individual components—prime mover (heat engine), generator, heat recovery, and electrical interconnection—configured into an integrated whole. The type of equipment that drives the overall system (i.e., the prime mover) typically identifies the CHP unit. 

Prime movers for CHP units include reciprocating engines, combustion or gas turbines, steam turbines, microturbines, and fuel cells. These prime movers are capable of burning a variety of fuels, including natural gas, coal, oil, and alternative fuels to produce shaft power or mechanical energy.

CHP Technology Options

Reciprocating or internal combustion engines (ICEs) are among the most widely used prime movers to power small electricity generators. Advantages include large variations in the size range available, fast start-up, good efficiencies under partial load efficiency, reliability, and long life.

Steam turbines are the most commonly employed prime movers for large power outputs. Steam at lower pressure is extracted from the steam turbine and used directly or is converted to other forms of thermal energy. System efficiencies can vary between 15 and 35% depending on the steam parameters.

Co-firing of biomass with coal and other fossil fuels can provide a short-term, low-risk, low-cost option for producing renewable energy while simultaneously reducing dependence on fossil fuels. Biomass can typically provide between 3 and 15 percent of the input energy into the power plant. Most forms of biomass are suitable for co-firing. 

Steam engines are also proven technology but suited mainly for constant speed operation in industrial environments. Steam engines are available in different sizes ranging from a few kW to more than 1 MWe.

A gas turbine system requires landfill gas, biogas, or a biomass gasifier to produce the gas for the turbine. This biogas must be carefully filtered of particulate matter to avoid damaging the blades of the gas turbine.  

Stirling engines utilize any source of heat provided that it is of sufficiently high temperature. A wide variety of heat sources can be used but the Stirling engine is particularly well-suited to biomass fuels. Stirling engines are available in the 0.5 to 150 kWe range and a number of companies are working on its further development.

A micro-turbine recovers part of the exhaust heat for preheating the combustion air and hence increases overall efficiency to around 20-30%. Several competing manufacturers are developing units in the 25-250kWe range. Advantages of micro-turbines include compact and light weight design, a fairly wide size range due to modularity, and low noise levels. 

Saudi ARAMCO's CHP Initiatives

Recently ARAMCO announced the signing of agreements to build and operate cogeneration plants at three major oil and gas complexes in Saudi Arabia. These agreements demonstrate ARAMCO's commitment to pursue energy efficiency in its operation. Upon completion, the cogeneration plants will meet power and heating requirements at Abqaiq, Hawiya and Ras Tanura plants. These plants are expected to generate a total on 900MW of power and 1,500 tons of steam per hour when they come onstream in 2016.

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Biogas from Animal Wastes

The Middle East and North Africa region has a strong animal population. The livestock sector, in particular sheep, goats and camels, plays an important role in the national economy of regional countries. Millions of animals are imported in MENA each year from around the world. In addition, the region has witnessed very rapid growth in the poultry sector. 

Animal Waste Management

Animal waste is a valuable source of nutrients and renewable energy. However, most of the waste is collected in lagoons or left to decompose in the open which pose a significant environmental hazard. The air pollutants emitted from manure include methane, nitrous oxide, ammonia, hydrogen sulfide, volatile organic compounds and particulate matter, which can cause serious environmental concerns and health problems. 

In the past, livestock waste was recovered and sold as a fertilizer or simply spread onto agricultural land. The introduction of tighter environmental controls on odour and water pollution means that some form of waste management is necessary, which provides further incentives for biomass-to-energy conversion. The biogas potential of animal manure can be harnessed both at small- and community-scale.

Anaerobic Digestion Process

Anaerobic digestion is a unique treatment solution for animal wastes as it can  deliver  positive  benefits  related  to  multiple  issues,  including  renewable  energy,  water pollution, and air emissions. Anaerobic digestion of animal manure is gaining popularity as a means to protect the environment and to recycle materials efficiently into the farming systems. Waste-to-Energy (WTE) plants, based on anaerobic digestion of cow manure, are highly efficient in harnessing the untapped renewable energy potential of organic waste by converting the biodegradable fraction of the waste into high calorific gases.

The establishment of anaerobic digestion systems for livestock manure stabilization and energy production has accelerated substantially in the past several years. There are thousands of digesters operating at commercial livestock facilities in Europe, United States,  Asia and elsewhere. which are generating clean energy and fuel. Many of the projects that generate electricity also capture waste heat for various in-house requirements.

Major Considerations

The main factors that influence biogas production from livestock manure are pH and temperature of the feedstock. It is well established that a biogas plant works optimally at neutral pH level and mesophilic temperature of around 35o C. Carbon-nitrogen ratio of the feed material is also an important factor and should be in the range of 20:1 to 30:1.

Animal manure has a carbon – nitrogen ratio of 25:1 and is considered ideal for maximum gas production. Solid concentration in the feed material is also crucial to ensure sufficient gas production, as well as easy mixing and handling. Hydraulic retention time (HRT) is the most important factor in determining the volume of the digester which in turn determines the cost of the plant; the larger the retention period, higher the construction cost.

Process Description

The fresh animal manure is stored in a collection tank before its processing to the homogenization tank which is equipped with a mixer to facilitate homogenization of the waste stream. The uniformly mixed waste is passed through a macerator to obtain uniform particle size of 5-10 mm and pumped into suitable-capacity anaerobic digesters where stabilization of organic waste takes place.

In anaerobic digestion, organic material is converted to biogas by a series of bacteria groups into methane and carbon dioxide. The majority of commercially operating digesters are plug flow and complete-mix reactors operating at mesophilic temperatures. The type of digester used varies with the consistency and solids content of the feedstock, with capital investment factors and with the primary purpose of digestion.

Biogas contain significant amount of hydrogen sulfide (H2S) gas which needs to be stripped off due to its highly corrosive nature. The removal of H2S takes place in a biological desulphurization unit in which a limited quantity of air is added to biogas in the presence of specialized aerobic bacteria which oxidizes H2S into elemental sulfur.

Biogas can be used as domestic cooking, industrial heating, combined heat and power (CHP) generation as well as a vehicle fuel. The digested substrate is passed through screw presses for dewatering and then subjected to solar drying and conditioning to give high-quality organic fertilizer.

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Biomass Energy in Jordan

Jordan has promising biomass energy potential in the form of municipal solid wastes, crop residues and organic industrial wastes.  Municipal solid wastes represent the best source of biomass in Jordan. In terms of quantity per capita and constituents, the waste generated in Jordan is comparable to most semi-industrialized nations. Agricultural biomass offers a low energy potential due to arid climate in most of the country.

The major biomass energy resources in Jordan are:

  • Municipal waste from big cities
  • Organic wastes from slaughterhouse, vegetable market, hotels and restaurants.
  • Organic waste from agro-industries
  • Animal manure, mainly from cows and chickens.
  • Sewage sludge and septic.
  • Olive mills.
  • Organic industrial waste

The total generation of municipal waste in Jordan is estimated at more than 2 million tons per year. In addition, an annual amount of 1.83 million cubic meter of septic and sewage sludge from treatment of 44 million cubic meter of sewage water is generated in Greater Amman area. The potential annual sewage sludge and septic generated in Amman can be estimated at 85,000 tons of dry matter. Jordan also generate significant amount of animal manure due to strong animal population in the form of cattle, sheep, camels, horses etc. 

Organic industrial wastes, either liquid or solid, is a good biomass resource and can be a good substrate for biogas generation. Anaerobic digestion is fast gaining popularity as one of the best waste management method for biomass utilization. The use of anaerobic digestion technology for biomassl waste management would be a significant step in Jordan’s emergence as a renewable energy hub in the MENA region. Jordan is planning to implement 40-50 MW of waste-to-energy projects by 2020.

Biogas Plant at Rusaifeh Landfill

The Government of Jordan, in collaboration with UNDP, GEF and the Danish Government, established 1MW biogas plant at Rusaifeh landfill near Amman in 1999.  The plant has been successfully operating since its commissioning and has recently been increased to 4MW. 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. The successful installation of the biogas project has made it a role model in the entire region and several big cities are striving to replicate the model.

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Zero-Waste Kitchens and Low-Energy Cooking

Food is the single largest source of waste. Worldwide, we throw away about a third of our food. More food ends up in landfills than plastic or paper. The enormous amount of wasted food depends on our cooking and eating habits.  Generally, it is easy to be sitting at home, in front of your television, consuming whatever you want then throwing every‑thing in the trash. But have we ever thought, where does the garbage go?

Zero-Waste Kitchens

Given that most of the domestic waste originates in the kitchen, a green home should definitely include a zero-waste kitchen. Zero waste kitchens is not about recycling more of our kitchen waste from plastics containers, metal cans and glass jars. It is about acting on needless waste and stopping it from coming into our homes in first place. Bea Johnson  introduced the concept of the 5Rs in her book Zero Waste Home which are Refuse, Reduce, Reuse, Recycle and Rot. The first and the second R address the prevention of waste, the third R encourage thoughtful consumption while the fourth and fifth Rs are the last stage processing of discards.

The Egyptian cuisine is considered one of the most time consuming and tiring kitchens with a lot of organic wastes. On top of that it is not energy efficient because of long cooking time. A lot of initiatives in Egypt started to promote for the idea of zero waste food. They collect food leftovers and pack them nicely and give them to needy people. Other NGOs can come to your door step and take for example cooking oil. Some also pay for it as incentives to encourage people not to throw it away. Throwing oil is not only a waste but also cause blockage for the sewage system. Food waste can be transformed to several sources of energy like biogas and biodiesel or even can be transformed to liquid fertilizers and compost.

Low Energy Cooking

Every winter we notice an increase in demand for gas cylinders.  Gas consumption increase during winter season due to long cooking time to prepare warm meals. It is not only waste of energy but waste of time as well.  We can reduce cooking time by following some simple practical tips.

  • Marinate the meat that we will consume along the month or even a week and then freeze them. They will take less time when cooked grilled or baked.
  • Another simple tip that is often overlooked way to reduce cooking time. Cook items you eat often in bulk – such as beef, chicken, rice and beans, or pasta – and freeze the leftovers for later use. If you’re freezing cooked pasta, drizzle a little oil over it to prevent sticking when you defrost.
  • Always make essential food components in a large quantity and freeze them. Like chopped onions, garlic, tomato sauce, broth etc.
  • It is important to match the size of any pot or casserole you use on the stove top elements.
  • Turn the heat down to the lowest setting after reaching boiling point. Higher heat just escapes round the side of the pot or boils the liquid faster but doesn't cook its contents faster.
  • Optimize the use of a preheated oven by cooking several dishes, either at once, or in a row.
  • Don't turn on the oven too soon before using. Just a few minutes is enough for pre-heating.
  • Turn off the oven or stovetop a few minutes early. The residual heat will keep cooking the food.
  • Use pressure cooker. It uses less energy than standard cooking pans. Reduction ranges from 70% up to 90 % and consequently reduces cooking time.
  • Adding one spoon of vinegar on meat reduce cooking time because it makes it more tender.
  • Do not add salt till late in cooking. Salt increase cooking time when added to beef for example. Add salt only if you are boiling water, as it makes it quicker to reach boiling point.
  • When you use the blinder, mixer or food processor, use it once for adequate amount not every day for small amounts. Freeze the extra amount for another use.

To conclude, it is not difficult to have a zero waste kitchen and it is easy to transform your kitchen's trash into valuable cash. Cooking can also be enjoyable, quick and yet energy efficient. We need always to remember that zero-waste kitchen is not only a physical kitchen, but it is mainly a mindset and lifestyle. 

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Food Wastes Disposal Methods

Food waste is one of the most prominent waste streams across Middle East, especially in GCC region.  The mushrooming of hotels, restaurants, fast-food joints and cafeterias in the Middle East region has resulted in the generation of huge quantities of food wastes. The proportion of food waste in municipal waste stream is gradually increasing and hence a proper food waste management strategy needs to be devised to ensure its eco-friendly and sustainable disposal in the Middle East. 

Food waste is an untapped energy source that mostly ends up rotting in landfills, thereby releasing greenhouse gases into the atmosphere. Food waste includes organic wastes generated in hotels, restaurants, canteens, cafeterias, shopping malls and industrial parks in the form of leftover food, vegetable refuse, stale cooked and uncooked food, meat, teabags, napkins, extracted tea powder, milk products etc. It is difficult to treat or recycle food waste since it contains high levels of sodium salt and moisture, and is mixed with other waste during collection. 

Food waste can be recycled by two main pathways:

  • Composting: A treatment that breaks down biodegradable waste by naturally occurring micro-organisms with oxygen, in an enclosed vessel or tunnel or pit
  • Anaerobic digestion or biogas technology: A treatment that breaks down biodegradable waste in the absence of oxygen, producing a renewable energy (biogas) that can be used to generate electricity and heat.

Composting

​​Composting provides an alternative to landfill disposal of food waste, however it requires large areas of land, produces volatile organic compounds and consumes energy. Compost is organic material that can be used as a soil amendment or as a medium to grow plants. Mature compost is a stable material with a content called humus that is dark brown or black and has a soil-like, earthy smell. It is created by: combining organic wastes (e.g., yard trimmings, food wastes, manures) in proper ratios into piles, rows, or vessels; adding bulking agents (e.g., wood chips) as necessary to accelerate the breakdown of organic materials; and allowing the finished material to fully stabilize and mature through a curing process. 

Anaerobic Digestion

Anaerobic digestion has been successfully used in several European and Asian countries to stabilize food wastes, and to provide beneficial end-products. Sweden, Austria, Denmark, Germany and England have led the way in developing new advanced biogas technologies and setting up new projects for conversion of food waste into energy. The relevance of biogas technology lies in the fact that it makes the best possible utilization of various organic wastes as a renewable source of clean energy. A biogas plant is a decentralized energy system, which can lead to self-sufficiency in heat and power needs, and at the same time reduces environmental pollution. 

Of the different types of organic wastes available, food waste holds the highest potential in terms of economic exploitation as it contains high amount of carbon and can be efficiently converted into biogas and organic fertilizer. Food waste can either be utilized as a single substrate in a biogas plant, or can be co-digested with organic wastes like cow manure, poultry litter, sewage, crop residues, abattoir wastes etc. 

 

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Waste-to-Energy Potential in Saudi Arabia

WastetoEnergy-SaudiArabiaThe Kingdom of Saudi Arabia has been grappling with the problem of solid waste in recent years. Around 15 million tons of municipal solid waste is generated in the country each year with per capita average of 1.4 kg per day. Depending on the population density and urban activities of that area, the major ingredients of Saudi Arabian MSW are food waste (40-51 %), paper (12-28 %), cardboard (7 %), plastics (5-17 %), glass (3-5 %), wood (2-8 %), textile (2-6 %), metals (2-8 %) etc.

Due to high population growth rate, (3.4% per annum), rapid urbanization (1.5% per annum) and fast economic development (3.5% yearly GDP rate), the generation rate of MSW is expected to reach 30 million tons per year by 2033. Waste management issues in Saudi Arabia are not only related to water, but also to land, air and the marine resources. The sustainable integrated solid waste management (ISWM) is still at the infancy level in the oil-rich kingdom

In Saudi Arabia, MSW is collected and sent to landfills or dumpsites after partial segregation and recycling. The major portion of collected waste is ends up in landfills untreated. Recycling of metals and cardboard is the main waste management practice in Saudi Arabia, which covers 10-15% of the total waste and usually carried out by the informal sector.

The landfill requirement in KSA is very high, about 28 million m3 per year. The problems of leachate, waste sludge, and methane and odor emissions are occurring in the landfills and its surrounding areas due to mostly non-sanitary or un-engineered landfills. However, in many cities the plans of new sanitary landfills are in place, or even they are being built by municipalities with capturing facilities of methane and leachate.

Waste-to-Energy provides the cost-effective and eco-friendly solutions to both energy demand and MSW disposal problems in Saudi Arabia. The choice of conversion technology depends on the type and quantity of waste (waste characterization), capital and operational cost, labor skill requirements, end-uses of products, geographical location and infrastructure.

Several waste to energy technologies such as pyrolysis, anaerobic digestion (AD), trans-esterification, fermentation, gasification, incineration, etc. have been developed. As per conservative estimates, electricity potential of 3 TWh per year can be generated, if all of the KSA food waste is utilized in biogas plants. Similarly, 1 and 1.6 TWh per year electricity can be generated if all the plastics and other mixed waste (i.e. paper, cardboard, wood, textile, leather, etc.) of KSA are processed in the pyrolysis, and refuse derived fuel (RDF) technologies respectively.

The current SWM activities of KSA require a sustainable and integrated approach with implementation of waste segregation at source, waste recycling, waste-to-energy and value-added product recovery. By 2032, Saudi government is aiming to generate about half of its energy requirements (about 72 GW) from renewable sources such as solar, nuclear, wind, geothermal and waste-to-energy systems.