MSW-to-Energy is the use of thermochemical and biochemical technologies to recover energy, usually in the form of electricity, steam and other fuels, from urban wastes. 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. These new technologies can reduce the volume of the original waste by 90%, depending upon composition and use of outputs.
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)
Air pollution control system for fly ash, bottom ash, 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 sewage sludge.
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
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.
The best way of dealing with waste, both economically and environmentally, is to avoid creating it in the first place. For effective waste management, waste minimization, reuse, recycle and energy recovery are more sustainable than conventional landfill or dumpsite disposal technique.
Olusosun is the largest dumpsite in Nigeria
Waste minimization is the process of reducing the amount of waste produced by a person or a society. Waste minimization is about the way in which the products and services we all rely on are designed, made, bought and sold, used, consumed and disposed of.
Reuse means using an item more than once. This includes conventional reuse where the item is used again for the same function and new-life reuse where it is used for a new function. For example, concrete is a type of construction waste which can be recycled and used as a base for roads; inert material may be used as a layer that covers the dumped waste on landfill at the end of the day.
Recycling of waste involves reprocessing the particular waste materials, including e-waste, so that it can be used as raw materials in another process. This is also known as material recovery. A well-known process for recycling waste is composting, where biodegradable wastes are biologically decomposed leading to the formation of nutrient-rich compost.
As far as waste-to-energy is concerned, major processes involved are mass-burn incineration, RDF incineration, anaerobic digestion, gasification and pyrolysis. Gasification and pyrolysis involves super-heating of municipal solid waste in an oxygen-controlled environment to avoid combustion. The primary differences among them relate to heat source, oxygen level, and temperature, from as low as about 300°C for pyrolysis to as high as 11 000°C for plasma gasification. The residual gases like carbon dioxide, hydrogen, methane etc are released after a sophisticated gas cleaning mechanism.
MSW incineration produce significant amounts of a waste called bottom ash, of which about 40% must be landfilled. The remaining 60% can be further treated to separate metals, which are sold, from inert materials, which are often used as road base.
The above mentioned techniques are trending in many countries and region. As of 2014, Tokyo (Japan) has nineteen advanced and sophisticated waste incinerator plants making it one of the cleanest cities. From the legislature standpoint, the country has implemented strict emission parameters in incinerator plants and waste transportation.
The European Union also has a similar legislature framework as they too faced similar challenges with regards to waste management. Some of these policies include – maximizing recycling and re-use, reducing landfill, ensuring the guidelines are followed by the member states.
Singapore has also turned to converting household waste into clean fuel, which both reduced the volume going into landfills and produced electricity. Now its four waste-to-energy plants account for almost 3% of the country’s electricity needs, and recycling rates are at an all-time high of 60%. By comparison, the U.S. sent 53% of its solid waste to landfills in 2013, recycled only 34% of waste and converted 13% into electricity, according to the US Environmental Protection Agency.
Trends in Waste Collection
Since the municipal solid waste can be a mixture of all possible wastes and not just ones belonging to the same category and recommended process, recent advances in physical processes, sensors, and actuators used as well as control and autonomy related issues in the area of automated sorting and recycling of source-separated municipal solid waste.
Automated vacuum waste collection systems that are located underground are also actively used in various parts of the world like Abu Dhabi, Barcelona, Leon, Mecca and New York etc. The utilization of the subsurface space can provide the setting for the development of infrastructure which is capable of addressing in a more efficient manner the limitations of existing waste management schemes.
AI-based waste management systems can help in route optimization and waste disposal
This technique also minimizes operational costs, noise and provides more flexibility. There are various new innovations like IoT-enabled garbage cans, electric garbage trucks, waste sorting robots, eco dumpster and mechanisms etc are also being developed and deployed at various sites.
Waste management is a huge and ever growing industry that has to be analyzed and updated at every point based on the new emergence of threats and technology. With government educating the normal people and creating awareness among different sector of the society, setting sufficient budgets and assisting companies and facilities for planning, research and waste management processes can help to relax the issues to an extent if not eradicating it completely. These actions not only help in protecting environment, but also help in employment generation and boosting up the economy.
Healthcare sector is growing at a very rapid pace, which in turn has led to tremendous increase in the quantity of medical waste generation in developing countries, especially by hospitals, clinics and other healthcare establishments. The quantity of healthcare waste produced in a typical developing country depends on a wide range of factors and may range from 0.5 to 2.5 kg per bed per day.
For example, India generates as much as 500 tons of biomedical wastes every day while Saudi Arabia produces more than 80 tons of healthcare waste daily. The growing amount of medical wastes is posing significant public health and environmental challenges across the world. The situation is worsened by improper disposal methods, insufficient physical resources, and lack of research on medical waste management. The urgent need of the hour is to healthcare sustainable in the real sense of the word.
Hazards of Healthcare Wastes
The greatest risk to public health and environment is posed by infectious waste (or hazardous medical waste) which constitutes around 15 – 25 percent of total healthcare waste. Infectious wastes may include items that are contaminated with body fluids such as blood and blood products, used catheters and gloves, cultures and stocks of infectious agents, wound dressings, nappies, discarded diagnostic samples, swabs, bandages, disposal medical devices, contaminated laboratory animals etc.
Improper management of healthcare wastes from hospitals, clinics and other facilities in developing nations pose occupational and public health risks to patients, health workers, waste handlers, haulers and general public. It may also lead to contamination of air, water and soil which may affect all forms of life. In addition, if waste is not disposed of properly, ragpickers may collect disposable medical equipment (particularly syringes) and to resell these materials which may cause dangerous diseases.
Inadequate healthcare waste management can cause environmental pollution, growth and multiplication of vectors like insects, rodents and worms and may lead to the transmission of dangerous diseases like typhoid, cholera, hepatitis and AIDS through injuries from syringes and needles contaminated with human.
In addition to public health risks associated with poor management of biomedical waste, healthcare wastes can have deleterious impacts on water bodies, air, soil as well as biodiversity. The situation is further complicated by harsh climatic conditions in many developing nations which makes disposal of medical waste more challenging.
The predominant medical waste management method in the developing world is either small-scale incineration or landfilling. However, the WHO policy paper of 2004 and the Stockholm Convention, has stressed the need to consider the risks associated with the incineration of healthcare waste in the form of particulate matter, heavy metals, acid gases, carbon monoxide, organic compounds, pathogens etc.
In addition, leachable organic compounds, like dioxins and heavy metals, are usually present in bottom ash residues. Due to these factors, many industrialized countries are phasing out healthcare incinerators and exploring technologies that do not produce any dioxins. Countries like United States, Ireland, Portugal, Canada and Germany have completely shut down or put a moratorium on medical waste incinerators.
Alternative Treatment Technologies
The alternative technologies for healthcare waste disposal are steam sterilization, advanced steam sterilization, microwave treatment, dry heat sterilization, alkaline hydrolysis, biological treatment and plasma gasification.
Steam sterilization is one of the most common alternative treatment method. Steam sterilization is done in closed chambers where both heat and pressure are applied over a period of time to destroy all microorganisms that may be present in healthcare waste before landfill disposal. Among alternative systems, autoclaving has the lowest capital costs and can be used to process up to 90% of medical waste, and are easily scaled to meet the needs of any medical organization.
Advanced autoclaves or advanced steam treatment technologies combine steam treatment with vacuuming, internal mixing or fragmentation, internal shredding, drying, and compaction thus leading to as much as 90% volume reduction. Advanced steam systems have higher capital costs than standard autoclaves of the same size. However, rigorous waste segregation is important in steam sterilization in order to exclude hazardous materials and chemicals from the waste stream.
Microwave treatment is a promising technology in which treatment occurs through the introduction of moist heat and steam generated by microwave energy. A typical microwave treatment system consists of a treatment chamber into which microwave energy is directed from a microwave generator. Microwave units generally have higher capital costs than autoclaves, and can be batch or semi-continuous.
Chemical processes use disinfectants, such as lime or peracetic acid, to treat waste. Alkaline digestion is a unique type of chemical process that uses heated alkali to digest tissues, pathological waste, anatomical parts, or animal carcasses in heated stainless steel tanks. Biological processes, like composting and vermicomposting, can also be used to degrade organic matter in healthcare waste such as kitchen waste and placenta.
Plasma gasification is an emerging solution for sustainable management of healthcare waste. A plasma gasifier is an oxygen-starved reactor that is operated at the very high temperatures which results in the breakdown of wastes into hydrogen, carbon monoxide, water etc. The main product of a plasma gasification plant is energy-rich syngas which can be converted into heat, electricity and liquids fuels. Inorganic components in medical wastes, like metals and glass, get converted into a glassy aggregate.
Rising rates of consumption necessitate an improved approach to resource management. Around the world, from Europe to Asia, governments have adapted their practices and policies to reflect renewability. They’ve invested in facilities that repurpose waste as source of energy, affording them a reliable and cheap source of energy.
This seems like progress, given the impracticality of older methods. Traditional sources of energy like fossil fuels are no longer a realistic option moving forward, not only for their finite nature but also within the context of the planet’s continued health. That said, the waste-to-energy sector is subject to scrutiny.
We’ll detail the reasons for this scrutiny, the waste-to-energy sector’s current status within the United States and speculations for the future. Through a concise analysis of obstacles and opportunities, we’ll provide a holistic perspective of the waste-to-energy progress, with a summation of its positive and negative attributes.
Status of Waste-to-Energy Sector
The U.S. currently employs 86 municipal waste-to-energy facilities across 25 states for the purpose of energy recovery. While several have expanded to manage additional waste, the last new facility opened in 1995. To understand this apparent lack of progress in the area of thermochemical treatment of MSW, budget represents a serious barrier.
One of the primary reasons behind the shortage of waste-to-energy facilities in the USA is their cost. The cost of construction on a new plant often exceeds $100 million, and larger plants require double or triple that figure to build. In addition to that, the economic benefits of the investment aren’t immediately noticeable.
The Palm Beach County Renewable Energy Facility is a RDF-based waste-to-energy (WTE) facility.
The U.S. also has a surplus of available land. Where smaller countries like Japan have limited space to work within, the U.S. can choose to pursue more financially viable options such as landfills. The expenses associated with a landfill are far less significant than those associated with a waste-to-energy facility.
Presently, the U.S. processes 14 percent of its trash in waste-to-energy (WTE) plants, which is still a substantial amount of refuse given today’s rate of consumption. On a larger scale, North America ranks third in the world in the waste-to-energy movement, behind the European nations and the Asia Pacific region.
Future of WTE Sector
Certain factors influence the framework of an energy policy. Government officials have to consider the projected increase in energy demand, concentrations of CO2 in the atmosphere, space-constrained or preferred land use, fuel availability and potential disruptions to the supply chain.
A waste-to-energy facility accounts for several of these factors, such as space constraints and fuel availability, but pollution remains an issue. Many argue that the incineration of trash isn’t an effective means of reducing waste or protecting the environment, and they have evidence to support this.
The waste-to-energy sector extends beyond MSW facilities, however. It also encompasses biofuel, which has seen an increase in popularity. The aviation industry has shown a growing dedication to biofuel, with United Airlines investing $30 million in the largest producer of aviation biofuel.
If the interest of United Airlines and other companies is any indication, the waste-to-energy sector will continue to expand. Though negative press and the high cost of waste-to-energy facilities may impede its progress, advances in technology promise to improve efficiency and reduce expenses.
Positives and Negatives
The waste-to-energy sector provides many benefits, allowing communities a method of repurposing their waste. It has negative aspects that are also important to note, like the potential for pollution. While the sector offers solutions, some of them come at a cost.
It’s true that resource management is essential, and adapting practices to meet high standards of renewability is critical to the planet’s health. However, it’s also necessary to recognize risk, and the waste-to-energy sector is not without its flaws. How those flaws will affect the sector moving forward is critical to consider.
Waste-to-energy (also known as energy-from-waste) is a complicated technology in the realm of renewable energy. There are a lot of hidden truths and myths about this technology that people need to be aware of. Renewable energy technologies, like solar and wind, have much more simple processes and gain most of the attention from media outlets.
On the converse, renewable energy sources that are highly complex like nuclear energy have a bunch of media attention as well.
So, why don’t we discuss a bit more about this relatively unknown technology and asset class? Here I’ll discuss a number of the most important facts about waste-to-energy (abbreviated as WTE).
Interesting Facts About Waste-to-Energy
Let’s get into our facts about waste-to-energy that you need to know.
1. Waste-to-Energy Can Provide Baseload Power
The most familiar renewable energy resources such as wind and solar can only provide power if the sun is shining or the wind is blowing. WTE projects can actually provide baseload power that is used to serve consumers and the grid no matter the time of day or if the sun is shining or not.
Baseload power is essentially when intermittent resources like solar and wind become more prevalent.
2. Not All WTE Projects are Clean and Green
While waste-to-energy projects would seem to be green and clean because they turn trash into power or gas. However, some projects require long hauling of trash to bring to the actual incineration facility. This actually ends up require much more emissions from the trash haulers than alternatives.
One solution to this would be to help promote the use of electric vehicles and electric vehicle technology to be installed in trucking, like waste hauling.
3. WTE Projects Can Reduce Use of Landfills
Landfills have increased at an exponential pace the in last 100 years. Waste-to-energy projects are an awesome alternative to landfills as the trash is used to provide electricity or fuel.
WTE projects reduce waste volumes by approximately 90%, which results in fewer landfills that are needed to process ash. This ends up protecting our natural resources and land in a dramatic fashion.
5. WTE Projects have Multiple Revenue Streams
Waste-to-energy projects are extremely complicated and expensive to build. Most of the investor economic interest is driven by financial incentives, renewable identification numbers, tax credits, etc. to help these projects get financed.
Beyond these other financial incentives, some of the waste-to-energy projects produce a byproduct, named biochar, which has multiple applications and fetches good prices. The biochar can usually end up providing the most value in the revenue stream or investability of the project itself.
In addition to other economic streams, waste-to-energy projects usually require high tipping fees. A tipping fee is what the trash hauler has to pay in order to dump the trash at the facility. With WTE projects, the tipping fee can end up being 50-60% of the overall revenue stack.
5. WTE Facilities are Net Greenhouse Gas Reducers
Methane has more than 20 times the potency of carbon dioxide and is ranked as a very dangerous contributor to climate change and warming of our planet. WTE facilities avoid the productions of methane and end up producing up to 10 times more the electricity than landfill gas projects. If you didn’t know, landfills can actually end up producing electricity by capture the methane gas and compressing it into a consumable natural gas for power.
Sweden is one of the best proponents of waste-to-energy in the world
WTE projects will usually have much more capacity than any landfill gas projects.
You can’t use waste-to-energy projects at your home similar to solar or even wind to get free electricity. However, knowing about projects in your area and the relevant suppliers will help you understand whether or not the technology is a perfect fit for your community. If you see a project coming online in your surrounding area, you should know how to ask the right questions.
At the end of the day, WTE projects are green and clean. They just need to have the right systems in place to make them more efficient and less risky to appeal new investor appetite. What fact was your favorite about waste-to-energy?
Do you know much about waste-to-energy projects? Let us know in the comments below. We’d love to hear from you.
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 Middle East.
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.
Waste to Energy Around the World
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.
Waste-to-Energy is now widely accepted as a part of sustainable waste management strategy.
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,
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.
Waste-to-Energy 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 Middle East.
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.
You know the saying: One person’s trash is another’s treasure. When it comes to recovering energy from municipal solid waste — commonly called garbage or trash— that treasure can be especially useful. Instead of taking up space in a landfill, we can process our trash to produce energy to power our homes, businesses and public buildings.
In 2015, the United States got about 14 billion kilowatt-hours of electricity from burning municipal solid waste, or MSW. Seventy-one waste-to-energy plants and four additional power plants burned around 29 million tons of MSW in the U.S. that year. However, just 13 percent of the country’s waste becomes energy. Around 35 percent is recycled or composted, and the rest ends up in landfills.
Recovering Energy Through Incineration
The predominant technology for MSW-to-energy plants is incineration, which involves burning the trash at high temperatures. Similarly to how some facilities use coal or natural gas as fuel sources, power plants can also burn MSW as fuel to heat water, which creates steam, turns a turbine and produces electricity.
Several methods and technologies can play a role in burning trash to create electricity. The most common type of incineration plant is what’s called a mass-burn facility. These units burn the trash in one large chamber. The facility might sort the MSW before sending it to the combustion chamber to remove non-combustible materials and recyclables.
These mass-burn systems use excess air to facilitate mixing, and ensure air gets to all the waste. Many of these units also burn the fuel on a sloped, moving grate to mix the waste even further. These steps are vital because solid waste is inconsistent, and its content varies. Some facilities also shred the MSW before moving it to the combustion chamber.
Another method for converting trash into electricity is gasification. This type of waste-to-energy plant doesn’t burn MSW directly, but instead uses it as feedstock for reactions that produce a fuel gas known as synthesis gas, or syngas. This gas typically contains carbon monoxide, carbon dioxide, methane, hydrogen and water vapor.
Approaches to gasification vary, but typically include high temperatures, high-pressure environments, very little oxygen and shredding MSW before the process begins. Common gasification methods include:
Air-fed systems, which use air instead of pure oxygen and temperatures between 800 and 1,800 degrees Celsius.
Plasma or plasma arc gasification, which uses plasma torches to increase temperatures to 2,000 to 2,800 degrees Celsius.
Syngas can be burned to create electricity, but it can also be a component in the production of transportation fuels, fertilizers and chemicals. Proponents of gasification report that it is a more efficient waste-to-energy method than incineration, and can produce around 1,000 kilowatt-hours of electricity from one ton of MSW. Incineration, on average, produces 550 kilowatt-hours.
Challenges of MSW-to-Energy
Turning trash into energy seems like an ideal solution. We have a lot of trash to deal with, and we need to produce energy. MSW-to-energy plants solve both of those problems. However, a relatively small amount of waste becomes energy, especially in the U.S.
Typical layout of MSW-to-Energy Plant
This lack may be due largely to the upfront costs of building a waste-to-energy plant. It is much cheaper in the short term to send trash straight to a landfill. Some people believe these energy production processes are just too complicated and expensive. Gasification, especially, has a reputation for being too complex.
Environmental concerns also play a role, since burning waste can release greenhouse gases. Although modern technologies can make burning waste a cleaner process, its proponents still complain it is too dirty.
Despite these challenges, as trash piles up and we continue to look for new sources of energy, waste-to-energy plants may begin to play a more integral role in our energy production and waste management processes. If we handle it responsibly and efficiently, it could become a very viable solution to several of the issues our society faces.
India’s waste-to-energy sector, which kicked off in 1987, is still searching for a successful role model, even after tens of millions of dollars of investment. In recent years, many ambitious waste-to-energy projects have been established or are being planned in different parts of the country, and it is hoped that things will brighten up in the coming years. Salman Zafar, CEO of BioEnergy Consult, talks to Power Today magazine on India’s tryst with waste-to-energy and highlights major challenges and obstacles in making waste-to-energy a success story in India.
Power Today: What are the challenges that the Waste to Energy sector faces in the current scenario where there is a rejuvenated interest in clean energy? Do you think the buzz around solar and wind power has relegated the Waste to Energy sector to the back benches?
Salman Zafar: India’s experience with waste-to-energy has been lackluster until now. The progress of waste-to-energy sector in India is hampered by multiples issues including
poor quality of municipal waste,
high capital and O&M costs of waste-to-energy systems,
lack of indigenous technology,
lack of successful projects and failure of several ambitious projects,
lack of coordination between municipalities, state and central governments,
heavy reliance on government subsidies,
difficulties in obtaining long-term Power Purchase Agreements (PPAs) with state electricity boards (SEBs)
lukewarm response of banks and financial institutions and (9) weak supply chain.
Waste-to-energy is different from solar (or wind) as it essentially aims to reduce the colossal amount of solid wastes accumulating in cities and towns all over India. In addition to managing wastes, waste-to-energy has the added advantage of producing power which can be used to meet rapidly increasing energy requirements of urban India. In my opinion, waste-to-energy sector has attracted renewed interest in the last couple of years due to Swachch Bharat Mission, though government’s heavy focus on solar power has impacted the development of waste-to-energy as well as biomass energy sectors.
Power Today: India has a Waste to Energy potential of 17,000 MW, of which only around 1,365 MW has been realised so far. How much growth do you expect in the sector?
The progress of waste-to-energy sector in India is dependent on resolution of MSW supply chain issues, better understanding of waste management practices, lowering of technology costs and flexible financial model. For the next two years, I am anticipating an increase of around 75-100 MW of installed capacity across India.
Power Today: On the technological front, what kinds of advancements are happening in the sector?
Salman Zafar: Nowadays, advanced thermal technologies like MBT, thermal depolymerisation, gasification, pyrolysis and plasma gasification are hogging limelight, mainly due to better energy efficiency, high conversion rates and less emissions. Incineration is still the most popular waste-to-energy technology, though there are serious emission concerns in developing countries as many project developers try to cut down costs by going for less efficient air pollution control system.
Power Today: What according to you, is the general sentiment towards setting up of Waste to Energy plants? Do you get enough cooperation from municipal bodies, since setting up of plants involves land acquisition and capital expenditure?
Salman Zafar: Waste-to-energy projects, be it in India or any other developing country, is plagued by NIMBY (not-in-my-backyard) effect. The general attitude towards waste-to-energy is that of indifference resulting in lukewarm public participation and community engagement in such projects.
Government should setup dedicated waste-to-energy research centres to develop lost-cost and low-tech waste to energy solutions
Lack of cooperation from municipalities is a major factor in sluggish growth of waste-to-energy sector in India. It has been observed that sometimes municipal officials connive with local politicians and ‘garbage mafia’ to create hurdles in waste collection and waste transport. Supply of poor quality feedstock to waste-to-energy plants by municipal bodies has led to failure of several high-profile projects, such as 6 MW MSW-to-biogas project in Lucknow, which was shut down within a year of commissioning due to waste quality issues.
Power Today: Do you think that government policies are in tandem when it comes to enabling this segment? What policies need to be changed, evolved or adopted to boost this sector?
Salman Zafar: A successful waste management strategy demands an integrated approach where recycling and waste-to-energy are given due importance in government policies. Government should strive to setup a dedicated waste-to-energy research centre to develop a lost-cost and low-tech solution to harness clean energy from millions of tons of waste generated in India.
The government is planning many waste-to-energy projects in different cities in the coming years which may help in easing the waste situation to a certain extent. However, government policies should be inclined towards inclusive waste management, whereby the informal recycling community is not robbed of its livelihood due to waste-to-energy projects.
Government should also try to create favourable policies for establishment of decentralized waste-to-energy plants as big projects are a logistical nightmare and more prone to failure than small-to-medium scale venture.
Note: This interview was originally published in June 2016 edition of Power Today magazine.
The increasing clamor for energy and satisfying it with a combination of conventional and renewable resources is a big challenge. Accompanying energy problems in almost all 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 tonnes in 2006, with estimates of up to 13 billion tonnes 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 up to 18 billion tonnes by year 2020. Ironically, most of the wastes are disposed of in open fields, along highways or burnt wantonly.
Size of the Industry
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. The global market for biological and thermochemical waste-to-energy technologies is expected to grow to USD 29.2 billion by 2022. Incineration, with energy recovery, is the most common waste-to-energy method employed worldwide.
Since 1995, the global WTE industry increased by more than 16 million tonnes of MSW. 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.
Advanced thermal technologies, like gasification and pyrolysis, and anaerobic digestion systems are beginning to make deep inroads in the waste-to-energy sector and are expected to increase their respective market shares on account of global interest in integrated waste management framework in urban areas. Scarcity of waste disposal sites coupled with growing waste volumes and solid waste management challenges are generating high degree of interest in energy-from-waste systems among policy-makers, urban planners, entrepreneurs, utility companies etc.
Currently, the European nations are recognized as global leaders of waste-to-energy 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. China is witnessing a surge in waste-to-energy installations and has plans to establish 125 new waste-to-energy plants during the twelfth five-year plan ending 2015.
Incineration is the most common waste-to-energy method used worldwide.
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.
Medical waste management is a concern of healthcare facilities all over the world; about 10-20% of the facility’s budget every year is spent on waste disposal. According to the WHO, about 85% of the total amount of generated waste is non hazardous but the remaining 15% is considered infectious, toxic or radioactive. While non-hazardous medical waste poses less problems, the risks and challenges of hazardous medical waste management must be considered carefully, since incineration or open burning of hazardous medical waste can result in emissions of dangerous pollutants such as dioxins and furans.
For this reason, measures must be taken to ensure safe disposal of hazardous medical waste waste in order to prevent negative impact on the environment or biological hazards, especially in developing countries.
Biologically hazardous waste can be a source of infection due to the harmful microorganisms it contains; the most exposed are hospital patients, hospital staff, health workers. However, the situation is potentially harmful for the general public as well. The risks include chemical burns, air pollution, radiation burns and toxic exposure to harmful pharmaceutical products and substances, such as mercury or dioxins, especially during the process of waste incineration.
Other risks can also derive from the incorrect disposal of needles and syringes; worldwide, it is estimated that, every year, about 16 billion infections are administered. Unfortunately, not all needles are safely eliminated, creating risk of infection but also the possibility of unintentional reuse. Even though this risk has decreased in recent years, unsafe infections are still responsible for many new cases of HIV, hepatitis B and hepatitis C.
Incorrect disposal of untreated healthcare waste can contaminate drinking and ground water in landfill, and also release dangerous chemical substances in the environment. Deficient waste incineration can also release hazardous pollutants in the air, and generate dioxins and furans, substances which have been linked to cancer and other adverse health conditions. Heavy metals, if incinerated, can lead to the diffusion of toxic metals in the environment.
The Way Forward
There is still a long way to go in order to ensure safe disposal of hazardous healthcare waste. A joint WHO/UNICEF assessment conducted in 2015 found that only 58% of analyzed facilities over 24 countries had appropriate medical waste disposal systems in place.
Strategies to improve healthcare waste segregation is an essential step in medical waste management
In the workplace, it is important to raise awareness and promote self-practices. Training in the areas of infection control and clinical waste management is important in order to maintain a clean, safe environment for patients and staff alike. Specialized industrial cleaning can also be effective in reducing risk of infection.
It is also essential to develop safe methods and technologies of treating hazardous medical waste, as opposed to waste incineration, which has already been shown to be ineffective and dangerous. Alternatives to incineration, such as microwaving or autoclaving, greatly reduce the release of hazardous emissions.
Finally, developing global strategies and systems to improve healthcare waste segregation is another essential step; since only about 15% of clinical waste is hazardous, treatment and disposal costs could be reduced significantly with proper segregation practices. Furthermore, these practices also reduce risks of infections for those workers who handle clinical waste.
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