MSW-to-Energy is the use of thermochemical 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 MSW-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.
Components of MSW-to-Energy Systems
Front-end MSW preprocessing
Conversion unit (reactor or anaerobic digester)
Gas cleanup and residue treatment plant
Energy recovery plant (optional)
Emissions clean up
Combustion of raw MSW, moisture less than 50%
Sufficient amount of oxygen is required to fully oxidize the fuel
Combustion temperatures are in excess of 850oC
Waste is converted into CO2 and water concern about toxics (dioxin, furans)
Any non-combustible materials (inorganic such as metals, glass) remain as a solid, known as bottom ash (used as feedstock in cement and brick manufacturing)
Fly ash APC (air pollution control residue) particulates, etc
Needs high calorific value waste to keep combustion process going, otherwise requires high energy for maintaining high temperatures
Well-known biochemical technology for organic fraction of MSW and domestic sewage.
Biological conversion of biodegradable organic materials in the absence of oxygen at mesophilic or thermophilic temperatures.
Residue is stabilized organic matter that can be used as soil amendment
Digestion is used primarily to reduce quantity of sludge for disposal / reuse
Methane gas is generated which is used for heat and power generation.
Can be seen as between pyrolysis and combustion (incineration) as it involves partial oxidation.
Exothermic process (some heat is required to initialize and sustain the gasification process).
Oxygen is added but at low amounts not sufficient for full oxidation and full combustion.
Temperatures are above 650oC
Main product is syngas, typically has net calorific value of 4 to 10 MJ/Nm3
Other product is solid residue of non-combustible materials (ash) which contains low level of carbon
Thermal degradation of organic materials through use of indirect, external source of heat
Temperatures between 300 to 850oC are maintained for several seconds in the absence of oxygen.
Product is char, oil and syngas composed primarily of O2, CO, CO2, CH4 and complex hydrocarbons.
Syngas can be utilized for energy production or proportions can be condensed to produce oils and waxes
Syngas typically has net calorific value (NCV) of 10 to 20 MJ/Nm
Use of electricity passed through graphite or carbon electrodes, with steam and/or oxygen / air injection to produce electrically conducting gas (plasma)
Temperatures are above 3000oC
Organic materials are converted to syngas composed of H2, CO
Inorganic materials are converted to solid slag
Syngas can be utilized for energy production or proportions can be condensed to produce oils and waxes
MSW-to-energy technologies can address a host of environmental issues, such as land use and pollution from landfills, and increasing reliance on fossil fuels. In many countries, the availability of landfill capacity has been steadily decreasing due to regulatory, planning and environmental permitting constraints. As a result, new approaches to waste management are rapidly being written into public and institutional policies at local, regional and national levels.
Financing of solid waste management projects can be pretty overwhelming for the city government, especially if the government see it as a critical part of the service they should render to the citizen and if the citizen also hold it as a basis for measuring the performance of the government and using it as one of the conditions for re-election.
All these aspects require proper funding in rendering a good waste management service to the society. As citizens, we hardly give any thought to the different aspects and what it takes to ensure it is carried out efficiently and effectively.
Financing Options for Solid Waste Management
There are four different options for financing of solid waste management projects. The option chosen will be dependent on various factors. The chief factor will be “what is the end goal of providing waste management service to citizen” and this is to be determined by the city government. Therefore, we say finance option is directly related to waste management goal of a city or State.
This primarily involves funding of waste management service entirely by the government through budgetary allocation. The government determines how it will generate the cash for service and this can be through taxation or redistribution of funds generated from other sources like sales of city natural resources or combination of various sources of funds.
In developing countries, this is generally inefficient due to the corruption within the government and lack of proper waste management capabilities in most instances. The government might decide to charge a service fee or not.
This involves infusing funds from the private sector into waste management service and also overseeing day-to-day running of the service. However, the hired company will charge a service fee which will be determined by calculating the amount of invested funds, operating cost, and profit envisaged. This will be spread over a period of time.
This financing option can deliver optimal result in providing waste management service but the private sector needs to be checked in order not to set a high fee that will end up scaring citizens which might lead to citizen abhorring the service.
Public-Private Partnership (PPP)
This is a special type of arrangement which brings together the government and private sector in providing funds and management capabilities for the delivery of waste management service.
All things being equal, this arrangement is best because the government will be able to regulate and have a say in how the service should be delivered especially as it relates to the setting of service fees which might be difficult in the solely private financing option. The PPP can equally be extended to be a Joint Venture (usually termed as Institutional PPP).
Donors and Grants
This funding mechanism is dependent on the interest of the donor organization. While it is a good way to develop a city’s waste management infrastructure, attracting and utilizing grants is solely reliant on what the donor considers as important. Hence, it might be difficult for a city government to dictate how the funds should be distributed among the various aspect of waste management.
Waste management projects based on public-private partnership (PPP) model has more chances of success in developing countries
However, this type of financing can be combined with a PPP arrangement to cater for a specific waste management aspect that is in tandem with the interest of the donor and can be part of the city government contribution to the PPP.
In conclusion, waste management financing is quite dynamic just like many other services and infrastructure provided by a city government and the best option for financing the provision of waste management service can only be made after appropriate due diligence and consultation with relevant stakeholders has been made and observed.
Kuwait, being one of the richest countries, is among the highest per capita waste generators in the world. Each year more than 2 million tons of solid waste is generated in the tiny Arab nation. High standards of living and rapid economic growth has been a major factor behind very high per capita waste generation of 1.4 to 1.5 kg per day.
Waste Disposal Method
The prevalent solid waste management method in Kuwait is landfill burial. Despite being a small country, Kuwait has astonishingly high number of landfills. There are 18 landfills, of which 14 sites are closed and 4 sites are still in operation. These landfills act as dumpsites, rather than engineered landfills.
Menace of Landfills
Infact, landfill sites in Kuwait are notorious for causing severe public health and environmental issues. Besides piling up huge amounts of garbage, landfill sites generate huge amount of toxic gases (methane, carbon dioxide etc) and plagued by spontaneous fires. Due to fast paced urban development, residential areas have expanded to the edges of landfill sites thus causing grave danger to public health.
The total land area of Kuwait is around 17,820 sq. km, out of which more than 18 sq. km is occupied by landfills. Area of the landfill sites ranges from tens to hundreds of hectares with waste deposition depth varying from 3 to 30 meters.
All kind of wastes, including municipal wastes, food wastes, industrial wastes, construction and demolition debris etc are dumped at these sites. Infact, about 90 percent of the domestic waste is sent to landfills which imply that more landfills will be required to tackle rapidly increasing volumes of solid wastes.
Most of the landfill sites have been closed for more than 20 years due to operational problems and proximity to new residential, commercial and industrial areas. These sites include Sulaibiyah, Kabed, Al Qurain, Shuaiba, Jleeb AI Shuyoukh, West Yarmouk, AI Wafra among others. Migration of leachate beyond landfill site boundaries is a frequent problem noticed across Kuwait. Groundwater contamination has emerged as a serious problem because groundwater occurs at shallow depths throughout the country.
The major landfill sites operated by municipality for solid waste disposal are Jleeb AI Shuyoukh, Sulaibiyah and Al-Qurain. The Qurain landfill, with area of 1 sq. km, was used for dumping of municipal solid waste and construction materials from 1975 until 1985 with total volume of dumped waste being 5 million m3.
The Sulaibiyah landfill site received more than 500 tons of waste per day from 1980 to 2000 with area spanning 3 sq. km. Jleeb AI Shuyoukh, largest landfill site in Kuwait with area exceeding 6 sq. km, received 2500 tons per day of household and industrial waste between 1970 and 1993. Around 20 million m3 of wastes was dumped in this facility during its operational period.
Over the years, most of the dumpsites in Kuwait have been surrounded by residential and commercial areas due to urban development over the years. Uncontrolled dumpsites were managed by poorly-trained staff resulting in transformation of dumpsites in breeding grounds for pathogens, toxic gases and spontaneous fires.
Most of the landfill sites have been forced to close, much before achieving their capacities, because of improper disposal methods and concerns related to public health and environment. Due to fast-paced industrial development and urban expansion, some of the landfills are located on the edges of residential, as is the case of Jleeb Al-Shuyoukh and Al-Qurain sites, endangering the lives of hundreds of thousands of people.
Solid waste management is one of the major environmental problems threatening the Kingdom of Morocco. More than 5 million tons of solid waste is generated across the country with annual waste generation growth rate touching 3 percent. The proper disposal of municipal solid waste in Morocco is exemplified by major deficiencies such as lack of proper infrastructure and suitable funding in areas outside of major cities.
According to the World Bank, it was reported that before a recent reform in 2008 “only 70 percent of urban wastes was collected and less than 10 percent of collected waste was being disposed of in an environmentally and socially acceptable manner. There were 300 uncontrolled dumpsites, and about 3,500 waste-pickers, of which 10 percent were children, were living on and around these open dumpsites.”
It is not uncommon to see trash burning as a means of solid waste disposal in Morocco. Currently, the municipal waste stream is disposed of in a reckless and unsustainable manner which has major effects on public health and the environment. The lack of waste management infrastructure leads to burning of trash as a form of inexpensive waste disposal. Unfortunately, the major health effects of burning trash are either widely unknown or grossly under-estimated to the vast majority of the population in Morocco.
The good news about the future of Morocco’s MSW management is that the World Bank has allocated $271.3 million to the Moroccan government to develop a municipal waste management plan. The plan’s details include restoring around 80 landfill sites, improving trash pickup services, and increasing recycling by 20%, all by the year 2020. While this reform is expected to do wonders for the urban population one can only hope the benefits of this reform trickle down to the 43% of the Moroccan population living in rural areas, like those who are living in my village.
Needless to say, even with Morocco’s movement toward a safer and more environmentally friendly MSW management system there is still an enormous population of people including children and the elderly who this reform will overlook. Until more is done, including funding initiatives and an increase in education, these people will continue to be exposed to hazardous living conditions because of unsuitable funding, infrastructure and education.
Peshawar is among the biggest cities in Pakistan with estimated population of 4 million inhabitants. Like most of the cities in Pakistan, solid waste management is a big challenge in Peshawar as the city generate 600-700 tons of municipal waste every day. with per capita generation of about 0.3 to 0.4 kg per day. Major part of the Peshawar population belongs to low and middle income area and based upon this fact, waste generation rate per capita varies in different parts of the city.
Municipal solid waste collection and disposal services in the city are poor as approximately 60 per cent of the solid wastes remain at collection points, or in streets, where it emits a host of pollutants into the air, making it unacceptable for breathing. A significant fraction of the waste is dumped in an old kiln depression around the southern side of the city where scavengers, mainly comprising young children, manually sort out recyclable materials such as iron, paper, plastics, old clothes etc.
Peshawar has 4 towns and 84 union councils (UCs). Solid waste management is one of their functions. Now city government has planned to build a Refuse Derived Fuel (RDF), Composting Plant and possibly a Waste to Energy Power Plant which would be a land mark of Peshawar city administration.
The UCs are responsible for door to door collection of domestic waste and a common shifting practice with the help of hand carts to a central pick-up points in the jurisdiction of each UC. Town Council is responsible for collection and transporting the mixed solid waste to the specified dumps which ends up at unspecified depressions, agricultural land and roadside dumps.
Open dumping of municipal wastes is widely practiced in Peshawar
Presently, there are two sites namely Hazar Khwani and Lundi Akhune Ahmed which are being used for the purpose of open dumping. Scavenging is a major activity of thousands of people in the city. An alarming and dangerous practice is the burning of the solid waste in open dumps by scavengers to obtain recyclables like glass and metals.
Almost 50 percent of recyclables are scavenged at transfer stations from the waste reaching at such points. The recyclable ratio that remains in the house varies and cannot be recovered by the authorities unless it is bought directly from the households. Only the part of recyclables reaching a certain bin or secondary transfer station can be exploited.
In some areas of city where waste is transported by private companies from transfer points to the disposal site out study found that scavengers could only get about 35% of the recyclables from the waste at transfer station. Considering the above fact, it can be inferred that in case municipality introduces efficient waste transfer system in the city, the amount of recyclables reaching the disposal facility may increase by 30% of the current amount. In case house-to-house collection is introduced the municipality will be able to take hold of 90% of the recyclables in the waste stream being generated from a household.
Waste management is highly context specific. Therefore it is important to distinguish between the conditions in the Global North and the Global South. Recent ILO figures suggest that 24 million people around the world are involved in the informal waste recycling sector, 80% of whom are waste pickers. Some estimates say that 1% of urban population in developing countries makes their primary household income through informal sector waste management activities. In Latin America alone, 4-5 million waste pickers earn their livelihood by being a part of the global recyclables supply chain.
Municipal budgets in the Global South are often limited and only a small percentage of that budget is assigned to waste management as compared to other municipal services. In the Global North waste management is recognized as a necessary public good and there is a greater willingness to pay for this service. Solid waste management (e.g. waste collection, transportation and recycling) is generally more labour intensive than in North America and Europe.
Urbanization in the Global South is often haphazard and unplanned; creating pockets of high and low income neighbourhoods. This creates logistical issues for the waste management service provision limiting options for viable waste collection and transportation. It is often the informal sector that steps in to fill this service gap.
The maturity and strength of the legal framework differs between the Global South and Global North. In North America and Europe the legal framework of waste management actively promotes and provides incentives for waste reduction, reuse and recovery whereas, despite recent developments in some countries, in Latin America legal frameworks remain focused upon mixed waste collection, transportation and disposal.
Recycling rates in Argentina are at 11% of the total waste stream with 95% of this material is recovered by the informal sector. This situation is replicated in many other countries. The informal sector recovers between 50% (e.g. Mexico) and 90% (e.g. Nicaragua) of the waste recovered and in the different countries of the region. Resource recovery and recycling is driven by market conditions. Materials that have a value are diverted from landfill through an informal network of recyclers and waste collectors.
The composition of waste is also very different in the Global South where organic waste is a much larger percentage of the waste stream. Because of the high percentage of organics in the waste stream in many cities in the Global South, innovations in decentralised composting and small scale biogas have been seen across the Global South (particularly in India) and can be used effectively by the informal sector, making a zero waste future a real possibility.
Role of Informal Recycling Sector
The informal sector can be highly effective at collecting and diverting garbage from landfill. When empowered with a facilitating legal framework, and collectively organized, the informal sector can be a key part of a sustainable resource recovery system. Using people power to increase recycling and diversion rates decreases the need for expensive, fixed, high technology solutions.
Understanding that the context for waste management is different between the Global North and Global South, and even in different areas within a city or region, means that no two situations will be the same. However, if there is one principle to follow it may well be to consider the context and look for the simplest solution. The greenest cities of the future may well be those that use flexible, adaptable solutions and maximize the work that the informal sector is already doing.
Note: This excerpt is being published with the permission of our collaborative partner Be Waste Wise. The original excerpt and its video recording can be found at this link
Latin America has one of the highest rates of urbanization in the world (80% urban population). By 2050, 90% of Latin America’s population will live in urban areas. This high rate of urbanization coupled with the global economic crisis has resulted in a waste management crisis. Municipalities find themselves unable to keep up with providing services and infrastructure to the urban populations.
Some cities in Latin America are facing this challenge by integrating the informal sector recyclers who are already active in their cities into the municipal solid waste management systems. In many cities, these “recicladores”, “cartoneros” or “catadores” (a few of the many names used for these workers in the region) are responsible for up to 90% of the recyclable waste recovered from the waste stream. Their work reduces municipal waste transportation costs, increases landfill lifetimes and supports the recycling chain throughout the region.
State of the Affairs
Every location presents its own challenges–there is no one-size-fits-all solution for integrated solid waste management systems–but relevant lessons can be drawn from both failed attempts and successful examples of informal sector integration in recycling systems in Latin America.
There are often two very different contexts within cities. In low-income neighborhoods waste collection services are often not provided and individuals and families accumulate and then sell their recyclables for additional income. In contrast, residents in high income neighborhoods do receive a waste collection service and their motivation for recycling is often related to greater levels of environmental awareness. It is important to consider these differences when designing waste management solutions.
Imported systems, and even locally derived systems based on examples from the Global North, generally focus on only one waste management scenario, making it difficult to manage the multiple competing scenarios in many cities in Latin America. There is often a bias towards the automation of waste management services, with the application of the high technology solutions used in the Global North. Regardless of the practicality or scientific evidence against certain high tech solutions, these are often sought after, thought to raise the bar of the city, to make it appear more sophisticated and modern. This leads to a misconception that working with informal sector is a step backwards in terms of urban development and modernization.
Conflicts between private waste management companies, the municipality and informal recyclers are common. The waste management companies do not want pickers on the landfill and wastepickers then go to the municipality for help. However, municipalities usually have very little experience to support the integration of formal and informal waste sectors. There are opportunities for new systems to emerge within this conflict. For example, during a similar conflict in Mexicali, Mundo Sustentable, with the help of Danone, intervened to help a private company work with the informal waste sector and improve recycling rates.
The Way Forward
In Latin America, there is a great opportunity to increase recycling rates by using labour-intensive solutions, which create jobs and support the development of a better urban environment in the cities. Municipal governments should be an integral part of these processes as they are usually responsible for solid waste management at local level. The key to catalyzing informal recycling sector integration will be the development and dissemination of successful examples.
Informal recyclers provide important a range of services to municipalities (such as waste collection and recovery in communities that would not otherwise have access to them), as well as cost savings (for example, the extension of landfill life and reduced transport costs), yet are rarely compensated for these benefits. Informal recyclers further form the foundation of an entire recycling supply chain, which ultimately benefits formal businesses, and often aliment entire local economies.
Challenges to Overcome
Municipal governments are often hesitant to work with informal actors, who are frequently seen as an unknown quantity. Yet often in the process of working and developing relations with informal recycler groups, their concerns diminish and they may actually exhibit enthusiasm. Likewise, the recyclers may gain in confidence and professionalism in their experience of formalization.
One major challenge facing efforts to integrate the informal sector in developing countries is the desire of some local governments to adopt technological solutions that appear more “modern.” In much of Latin America, however, low-cost, low-tech solutions tend to be more viable and sustainable.
The main difference between Latin America and the countries of the Global North is that solid waste management is a labor intensive system. It is made up of workers and hence has an important social component. The ILO estimated there is 24 million of people working in the global recycling supply chain, but those at the bottom of the pyramid, the wastepickers, make up 80%. They remain the lowest paid even though they make an enormous contribution to their cities.
It is important to understand that highly sophisticated, high technology systems are not required for effective resource recovery. In many cities in Latin America between 80-90% of everything that is recycled is recovered by the informal recycling sector.
Despite the fact that there is little or no public investment in waste management or recycling infrastructure, cities with an active informal sector reach twice the rate of fully formalized municipal solid waste management systems. As an example, the recycling rate is 60% in Cairo, while in Rotterdam (and other cities in the Global North) recycling levels only reach 30%, even with a high public investment in the system (UN Habitat, 2010).
When designing infrastructure and waste management systems we must consider not only the waste management and resource recovery needs but also the social side of the system. In order to be effective, efforts to upgrade waste management services should go hand in hand with efforts to formalise and integrate the informal sector.
Bogota – A Success Story
An example of a recent success story is that after 27 years of struggle, the waste pickers in Bogota, Colombia have managed to change the government’s outlook on their work and their existence. They are now included in the system and are paid per tonne of waste collected, just like any other private sector collection and waste management company would be. They have become recognized as public service providers, acknowledged for their contribution to the environment and public health of the city.
The key challenge is to be much more creative and understand that in order to improve the working conditions of waste pickers and in order to increase recycling rates, we don’t need high technology. We need a systemic approach and this can be very simple sometimes infrastructure as simple as a roof [on a sorting area] can be effective in improving working conditions.
Note: This excerpt is being published with the permission of our collaborative partner Be Waste Wise. The original excerpt and its video recording can be found at this link
A combination of high fuel prices and a search for alternative technologies, combined with massive waste generation has led to countries in the Middle East region to consider Waste to Energy (or WtE) as a sustainable waste management strategy and cost-effective fuel source for the future. We look at the current state of the WtE market in the region.
It is estimated that each person in the United Arab Emirates produces 2 kg of municipal solid waste per day – that puts the total waste production figure somewhere in the region of 150 million tonnes every year. Given that the population currently stands at over 9.4 million (2013) and is projected to see an annual average growth figure of 2.3% over the next six years, over three times the global average, it’s clear that this is a lot of waste to be disposed of. In addition, the GCC nations in general rank in the bottom 10% of the sustainable nations in the world and are also amongst the top per capita carbon-releasers.
When we also consider that UAE are actively pursuing alternative energy technologies to supplement rapidly-decreasing and increasingly-costly traditional fossil fuels, mitigate the harmful effects of landfill, and reduce an ever-increasing carbon footprint, it becomes apparent that high on their list of proposed solutions is Waste to Energy (WtE). It could be an ideal solution to the problem.
What is WtE
Waste-to-Energy works on the simple principle of taking waste and turning it into a form of energy. This can be electricity, heat or transport fuels, and can be achieved in a variety of ways – the most common of which is incineration. MSW is taken to a WtE plant, incinerated at high temperatures and the resultant heat is used to boil water which creates steam to turn turbines, in the same way that burning gas or coal produces power. Gasification and anaerobic digestion are two further WtE methods which are also used.
However, WtE has several advantages over burning fossil fuels. Primarily amongst them are the potential to minimise landfill sites which have caused serious concern for many years. They are not only unsightly, but can also be contaminated, biologically or chemically. Toxic waste can leach into the ground beneath them and enter the water table.
Landfill sites also continuously emit carbon dioxide and methane, both harmful greenhouse gases – in addition methane is potentially explosive. Sending MSW to landfill also discourages recycling and necessitates more demand for raw materials. Finally, landfill sites are unpleasant places which attract vermin and flies and give off offensive odours.
WtE has been used successfully in many countries around the world for a long time now. Europe is the most enthusiastic proponent of WtE, with around 450 facilities; the Asia-Pacific region has just over 300; the USA has almost 100. In the rest of the world there are less than 30 facilities but this number is growing. Globally, it is estimated that the WtE industry is growing at approximately US $2 billion per annum and will be valued at around US $80 billion by the year 2022.
The USA ranks third in the world for the percentage of waste which is incinerated for energy production. Around 16% of the rubbish that America produces every day is burned in its WtE plants. Advocates claims the advantages are clear: reducing the amount of greenhouse gas emitted into the environment (estimates say that burning one ton of waste in a WtE plant saves between one half and one ton of greenhouse gases compared to landfill emissions, or the burning of conventional fuels), freeing up land which would normally be used for landfill (and, therefore, extending the life of existing landfill sites), encouraging recycling (some facilities have managed to reduce the amount of waste they process by up to 90% and the recycling of ferrous and non-ferrous metals provides an additional income source), and, perhaps most importantly, producing a revenue stream from the sale of the electricity generated.
In one small county alone, Lancaster, Pennsylvania, with a population of just over half-a-million people, more than 4.4 billion kWh of electricity has been produced through WtE in the last 20 years. This has generated over USD $256 million through its sale to local residents.
WtE in the Middle East
Given WtE’s potential to not only reduce greenhouse gas emissions and pollution on a local scale, but also to produce much-needed electricity in the region, what is the current state of affairs in the Middle East. There are several WtE initiatives already underway in the region. Qatar was the first GCC country to implement a waste-to-energy programme and currently generates over 30MW of electricity from its Domestic Solid Waste Management Center (DSWMC) located at Messeid (Doha). Saudi Arabia and the UAE have both stated that they have WtE production capacity targets of 100MW. Bahrain, Kuwait and Oman are also seriously considering waste-to-energy as a means to tackle the worsening waste management problem.
Abu Dhabi’s government is currently spending around US $850 million to build a 100 MW plant which is expected to be operational by 2017 and which will supply around 20,000 households with electricity. In Sharjah, the world’s largest household waste gasification plant, costing in excess of US $480 million, is due to be open in 2015.
However, not all the GCC members are as enthusiastic about WtE. Dubai’s government has recently scrapped plans for a US $2 billion project which would have made use of the 7,800 tonnes of domestic waste which is produced in Dubai every single day.
We asked Salman Zafar, Founder of Doha-based EcoMENA, a popular sustainability advocacy, why given the sheer scale of the waste in the Gulf region, the production of this form of energy is still in its infancy. “The main deterrent in the implementation of WtE projects in the Middle East is the current availability of cheap sources of energy already available, especially in the GCC,” he commented.
Salman Zafar further says, “WtE projects demand a good deal of investment, heavy government subsidies, tipping fees, power purchase agreements etc, which are hard to obtain for such projects in the region.” “The absence of a sustainable waste management strategy in Middle East nations is also a vital factor behind the very slow pace of growth of the WtE sector in the region. Regional governments, municipalities and local SWM companies find it easier and cost-effective to dump untreated municipal waste in landfills,” he added.
So, how can WtE contribute towards the region’s growing power demand in the future?
“Modern WtE technologies, such as RDF-based incineration, gasification, pyrolysis, anaerobic digestion etc, all have the ability to transform power demand as well as the waste management scenario in the region,” he continued. “A typical 250 – 300 tons per day WtE plant can produce around 3 – 4 MW of electricity and a network of such plants in cities across the region can make a real difference in the energy sector as well as augmenting energy reserves in the Middle East. In fact, WtE plants also produce a tremendous about of heat energy which can be utilised in process industries, further maximising their usefulness,” Salman Zafar concluded.
New technologies naturally take time to become established as their efficiency versus cost ratios are analysed. However, it is becoming increasingly clearer that waste-to-energy is a viable and efficient method for solid waste management and generation of alternative energy in the Middle East.
Saudi Arabia has been witnessing rapid industrialization, high population growth rate and fast urbanization which have resulted in increased levels of pollution and waste. Solid waste management is becoming a big challenge for the government and local bodies with each passing day. With population of around 29 million, Saudi Arabia generates more than 15 million tons of solid waste per year. The per capita waste generation is estimated at 1.5 to 1.8 kg per person per day.
Solid waste generation in the three largest cities – Riyadh, Jeddah and Dammam – exceeds 6 million tons per annum which gives an indication of the magnitude of the problem faced by civic bodies. More than 75 percent of the population is concentrated in urban areas which make it necessary for the government to initiate measures to improve recycling and waste management scenario in the country.
In Saudi Arabia, municipal solid waste is collected from individual or community bins and disposed of in landfills or dumpsites. Saudi waste management system is characterized by lack of waste disposal and tipping fees. Recycling, reuse and energy recovery is still at an early stage, although they are getting increased attention. Waste sorting and recycling are driven by an active informal sector. Recycling rate ranges from 10-15%, mainly due to the presence of the informal sector which extracts paper, metals and plastics from municipal waste.
Recycling activities are mostly manual and labor intensive. Composting is also gaining increased interest in Saudi Arabia due to the high organic content of MSW (around 40%). Efforts are also underway to deploy waste-to-energy technologies in the Kingdom. All activities related to waste management are coordinated and financed by the government.
The Saudi government is aware of the critical demand for waste management solutions, and is investing heavily in solving this problem. The 2011 national budget allocated SR 29 billion for the municipal services sector, which includes water drainage and waste disposal. The Saudi government is making concerted efforts to improve recycling and waste disposal activities.
Cities around the world produce huge quantity of municipal wastewater (or sewage) which represents a serious problem due to its high treatment costs and risk to environment, human health and marine life. Sewage generation is bound to increase at rapid rates due to increase in number and size of urban habitats and growing industrialization.
An attractive disposal method for sewage sludge is to use it as alternative fuel source in cement industry. 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.
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 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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