The disposal of municipal solid waste is the second most major concern for public health in developing countries because of population explosion, rampant poverty and high urbanization rates combined with poor government funding to curb waste management. Factors such as waste composition, technologies and lack of infrastructure have been found to set apart the good management of solid wastes in developing nations. Municipal waste is mainly comprised of paper, vegetable matter, plastics, metals, textiles, rubber and glass. In some countries (developing as well as developed), municipal solid waste is mixed with medical wastes and this may pose health risk to waste handlers and general public.
Burying the wastes has become most preferred method for waste management in many countries. This method is still used in many more countries. Tackling environmental issues has become more important and more preferred than pollution and consumption of unsustainable utilization of resources. Most importantly, the primary objective of waste management is to put emphasis on protecting the people and environment from potentially harmful effects of waste.
Methods of Solid Waste Management
Depending on the types of wastes generated, four methods of solid waste management has been used throughout the history, i.e. dumping, incineration, recycling and waste prevention. Waste generated from household is much different from industrial waste, agricultural waste, medical waste or mining wastes.
When wastes contain any hazardous component, or it has capability to become hazardous with time, poses very serious threat to environment and health. Hazardous wastes generated needs to be handled very carefully, with special techniques. This is one of the major reasons of open landfills are getting replaced with sanitary landfills.
At a landfill, wastes are covered with thick layer of soil. By the late 1950, this practice was very common for waste management across the world. Earlier landfills had considerable sludge and methane emissions, which were harmful to the environment as well as animal and human health. But these issues have been resolved largely by modern disposal methods, which were developed around 20 years ago. Modern landfills are equipped with thick layer of clay followed by plastic sheets. This method was practiced by some nations and still going on.
In 1930-1940, many cities in USA adopted new technology to curb waste issues by burning at high temperature, this method is known as incineration. During initial years, this method was not very efficient and emit very large amount of poisonous gasses, this is the major reason of incinerators shut down during that period. During mid-1970s, scientists modified incinerators to generate energy, which are known as waste to energy plants. But after around a decade, it has become major issue to build these plants, again because of emission issues.
With development of technology, waste burning in advanced form of incinerators became common in 1970s, researchers across the world bet on incinerators or waste to energy plants for solution to energy crisis in 1973. However, with realisation of impact on environment and air quality, it become very difficult to find location to build any waste to energy plants, mainly because of public opposition. Another issue with incinerator is production of ashes, which contain huge amount of heavy metals, toxic and inorganic compounds.
Incineration is the most common waste-to-energy method used worldwide.
Future Outlook of Solid Waste Management
The overall concept of wastes needs to be considered economically, it will be more considered as economically viable product if waste is considered as an inefficiency of the production process not as rejected residue of waste product. A permanent rejection or heavy restriction into products which produces waste that cannot be accumulated back into the environment safely.
The major challenge in waste management is to persuade people/community to consider waste as a resource, rather than a liability on society, which can be created with more innovation and technological development of manufacturing industry, waste processing industry and new business model and plans.
This planning system will create circular economy where product value created by inputs (e.g. energy, materials, labour etc.) is extended by enabling a material that goes into circular economy, beyond product life. We go from mineral to metals to product then back to minerals/metals. By understanding economic cycle of waste, people will understand the creation of opportunities to more sustainable product in future with limited resources.
China is the world’s largest MSW generator, producing as much as 175 million tons of waste every year. With a current population surpassing 1.37 billion and exponential trends in waste output expected to continue, it is estimated that China’s cities will need to develop an additional hundreds of landfills and waste-to-energy plants to tackle the growing waste management crisis.
China’s three primary methods for municipal waste management are landfills, incineration, and composting. Nevertheless, the poor standards and conditions they operate in have made waste management facilities generally inefficient and unsustainable. For example, discharge of leachate into the soil and water bodies is a common feature of landfills in China. Although incineration is considered to be better than landfills and have grown in popularity over the years, high levels of toxic emissions have made MSW incineration plants a cause of concern for public health and environment protection.
Salman Zafar, a renowned waste management, waste-to-energy and bioenergy expert was interviewed to discuss waste opportunities in China. As Mr. Zafar commented on the current problems with these three primary methods of waste management used by most developing countries, he said, “Landfills in developing countries, like China and India, are synonymous with huge waste dumps which are characterized by rotting waste, spontaneous fires, toxic emissions and presence of rag-pickers, birds, animals and insects etc.” Similarly, he commented that as cities are expanding rapidly worldwide, it is becoming increasingly difficult to find land for siting new landfills.
On incineration, Zafar asserted that this type of waste management method has also become a controversial issue due to emission concerns and high technology costs, especially in developing countries. Many developers try to cut down costs by going for less efficient air pollution control systems”. Mr. Zafar’s words are evident in the concerns reflected in much of the data that waste management practices in China are often poorly monitored and fraudulent, for which data on emission controls and environmental protection is often elusive.
Similarly, given that management of MSW involves the collection, transportation, treatment and disposal of waste, Zafar explains why composting has also such a small number relative to landfills for countries like China. He says, “Composting is a difficult proposition for developing countries due to absence of source-segregation. Organic fraction of MSW is usually mixed with all sorts of waste including plastics, metals, healthcare wastes and industrial waste which results in poor quality of compost and a real risk of introduction of heavy metals into agricultural soils.” Given that China’s recycling sector has not yet developed to match market opportunities, even current treatment of MSW calls for the need of professionalization and institutionalization of the secondary materials industry.
While MSW availability is not an issue associated with the potential of the resource given its dispersion throughout the country and its exponential increase throughout, around 50 percent of the studies analyzed stated concerns for the high moisture content and low caloric value of waste in China, making it unattractive for WTE processes.
Talking about how this issue can be dealt with, Mr. Zafar commented that a plausible option to increase the calorific value of MSW is to mix it with agricultural residues or wood wastes. Thus, the biomass resources identified in most of the studies as having the greatest potential are not only valuable individually but can also be processed together for further benefits.
Among the major challenges on the other hand, were insufficient or elusive data, poor infrastructure, informal waste collection systems and the lack of laws and regulations in China for the industry. Other challenges included market risk, the lack of economic incentives and the high costs associated with biomass technologies. Nevertheless, given that the most recurring challenges cited across the data were related to infrastructure and laws and regulations, it is evident that China’s biomass policy is in extreme need of reform.
China’s unsustainable management of waste and its underutilized potential of MSW feedstock for energy and fuel production need urgent policy reform for the industry to develop. Like Mr. Zafar says, “Sustainable waste management demands an integration of waste reduction, waste reuse, waste recycling, and energy recovery from waste and landfilling. It is essential that China implements an integrated solid waste management strategy to tackle the growing waste crisis”.
China’s government will play a key role in this integrated solid waste management strategy. Besides increased cooperation efforts between the national government and local governments to encourage investments in solid waste management from the private sector and foster domestic recycling practices, first, there is a clear need to establish specialized regulatory agencies (beyond the responsibilities of the State Environmental Protection Administration and the Ministry of Commerce) that can provide clearer operating standards for current WTE facilities (like sanitary landfills and incinerators) as well as improve the supervision of them.
It is essential that China implements an integrated solid waste management strategy to tackle the growing waste crisis
Without clear legal responsibility assigned to specialized agencies, pollutant emissions and regulations related to waste volumes and operating conditions may continue to be disregarded. Similarly, better regulation in MSW management for efficient waste collection and separation is needed to incentivize recycling at the individual level by local residents in every city. Recycling after all is complementary to waste-to-energy, and like Salman Zafar explains, countries with the highest recycling rates also have the best MSW to energy systems (like Germany and Sweden).
Nevertheless, without a market for reused materials, recycling will take longer to become a common practice in China. As Chinese authorities will not be able to stop the waste stream from growing but can reduce the rate of growth, the government’s role in promoting waste management for energy production and recovery is of extreme importance.
Incineration is the most popular waste treatment method that transforms waste materials into useful energy. The incineration process converts waste into ash, flue gas, and heat. The type of thermal WTE technology most commonly used worldwide for municipal solid waste is the moving grate incineration. These moving grate incinerators are even sometimes referred to as as the Municipal Solid Waste Incinerators (MSWIs). As of August 2013, of more than 1000 of 1200 Waste-to-Energy plants (among 40 different countries) there is no pre-treatment of the MSW before it is combusted using a moving grate. The hot combustion gases are commonly used in boilers to create steam that can be utilized for electricity production. The excess energy that can’t be used for electricity can possibly be used for industrial purposes, such as desalination or district heating/cooling
Benefits of Moving Grate
The moving grate incineration technology is lenient in that it doesn’t need prior MSW sorting or shredding and can accommodate large quantities and variations of MSW composition and calorific value. With over 100 years of operation experience, the moving grate incineration system has a long track record of operation for mixed MSW treatment. Between 2003 and 2011, it was reported that at least 106 moving grate incineration plants were built worldwide for MSW treatment. Currently, it is the main thermal treatment used for mixed MSW.
Compared to other thermal treatment technologies, the unit capacity and plant capacity of the moving grate incineration system is the highest, ranging from 10 to 920 tpd and 20 to 4,300 tpd. This system is able to operate 8,000 hours per year with one scheduled stop for inspection and maintenance of a duration of roughly one month. Today, the moving grate incineration system is the only treatment type which has been proven to be capable of treating over 3,000 tpd of mixed MSW without requiring any pretreatment steps. Being composed of six lines of furnace, one of the world’s largest moving grate incineration plants has a capacity of 4,300 tpd and was installed in Singapore by Mitsubishi in 2000
Moving-grate incineration requires that the grate be able to move the waste from the combustion chamber to allow for an effective and complete combustion. A single incineration plant is able to process thirty-five metric tons of waste per hour of treatment.
The MSW for a moving grate incinerator does not require pretreatment. For this reason, it is easier to process large variations and quantities. Most of these incineration plants have hydraulic feeders to feed as-received MSW to the combustion chamber (a moving grate that burns the material), a boiler to recover heat, an air pollution control system to clean toxins in the flus gas, and discharge units for the fly ash. The air or water-cooled moving grate is the central piece of the process and is made of special alloys that resist the high temperature and avoid erosion and corrosion.
Working principle of a grate incinerator
The waste is first dried on the grate and then burnt at a high temperature (850 to 950 degrees C) accompanied with a supply of air. With a crane, the waste itself is emptied into an opening in the grate. The waste then moves towards the ash pit and it is then treated with water, cleaning the ash out. Air then flows through the waste, cooling the grate. Sometimes grates can also be cooled with water instead. Air gets blown through the boiler once more (but faster this time) to complete the burning of the flue gases to improve the mixing and excess of oxygen.
Suitability for Developing Nations
For lower income and developing countries with overflowing landfills, the moving grate incinerator seems suitable and efficient. Moving grate incineration is the most efficient technology for a large-scale mixed MSW treatment because it is the only thermal technology that has been able to treat over 3,000 tons of mixed MSW per day. It also seems to be considerably cheaper than conventional technologies.
Compared to other types of Waste-to-Energy technologies, this type of system also shows the highest ability to handle variation of MSW characteristics. As for the other incineration technologies like gasification and pyrolysis technologies, these are either limited in small-scale, limited in material for industrial/hazardous waste treatment, requiring preprocessing of mixed MSW before feeding, which make them not suitable for large-scale mixed MSW treatment.
For the reduction of significant waste volume, treatment using a moving grate incinerator with energy recovery is the most commonly used form of waste-to-energy (WTE) technology. The moving grate’s ability to treat significant volumes of waste efficiently, while not requiring pre-treatment or sorting is a major advantage that makes this suitable for developing countries. This technology could provide many other benefits to such nations. Implementing moving grate incinerators is most suitable for developing nations because not only will it reduce waste volume, but it would also reduce the demand for landfills, and could recover energy for electricity.
Kamuk, Bettina, and Jørgen Haukohl. ISWA Guidelines: Waste to Energy in Low and Middle Income Countries. Rep. International Solid Waste Association, 2013. Print.
“Municipal Solid Waste Management and Waste-to-Energy in the United States, China and Japan.” Themelis, Nickolas J., and Charles Mussche. 2nd International Academic Symposium on Enhanced Landfill Mining, Houthalen and Helchteren, Belgium, 4-16 October 2013. Enhanced Landfill Mining. Columbia University.
“Review of MSW Thermal Treatment Tecnologies.” Lai, K.C.K., I.M.C. Lo, and T.T.Z. Liu. Proceedings of the International Conference on Solid Waste 2011- Moving Towards Sustainable Resource Management, Hong Kong SAR, P.R. China, 2 – 6 May 2011. Hong Kong SAR, P.R. China. 2011. 317-321. Available: http://www.iswa.org/uploads/tx_iswaknowledgebase/10_Thermal_Technology.pdf. accessed on 14 April 2016.
UN-HABITAT, 2010. Collection of Municipal Solid Waste in Developing Countries. United Nations Human Settlements Programme (UN-HABITAT), Nairobi. Available:
Waste management is an important tool for curbing climate change and for keeping our environment clean and healthy. Methane generated from biodegradable wastes is a powerful greenhouse gas, and when it’s not captured and used as a fuel it contributes to rapid warming of the atmosphere. Estimates suggest that biodegradable waste in dump sites and uncapped landfill sites are contributing far more methane to the atmosphere than previously thought. What’s more, urban food waste is predicted to increase by 44% from 2005 to 2025, and with no proper management in place, will significantly add to global greenhouse gas emissions.
Worryingly, 38 of the world’s 50 largest dumps are close to the sea, contributing to marine and coastal pollution. The accumulation of plastics in the marine food chain is causing global concern. While we don’t yet know how to clean the oceans, stemming the flow of waste into marine environments would be a step in the right direction.
40% of the world’s waste ends up in open dumps. These aren’t even what you’d call “landfill”. They don’t have any impervious lining to prevent noxious leachate from entering the surrounding environment, nor are they capped to prevent the spread of disease. In fact, in India, the Philippines and Indonesia, the health risk from open dumping of waste is greater than the risk of malaria[i].
3.5 billion people in the world lack access to proper waste management. That figure is expected to grow to 5 billion by 2050. Respiratory diseases, gastrointestinal diseases and occupational health risks add to the misery experienced by the 50,000+ people living from open dumps.
Waste is any material that is no longer wanted for its original purpose. The owner doesn’t have a need for it, and so discards it. Even valuable items can and do end up as waste purely because someone has thrown them away. The recent (and rather brilliant) BBC programme Hugh’s War on Waste shone the spotlight on attitudes towards disposable fashion. A look through the bins of a typical street uncovered a startling amount of clothing that had been thrown away, despite it still being in perfectly good condition. This highlights a simple fact: there is plenty of value in waste.
Estimates suggest there are 40 million people globally who are making their living from waste – half of these are working informally.
During the last recession in the UK, the waste management sector was one of the only industries to keep growing, resulting in it being termed the “Green Star of the Economy”.
Showing people how to turn a waste stream into something valuable isn’t rocket science. There are lots of examples of informal, community-based, grassroots recycling and upcycling projects that generate wealth for the poorest in society.
Internet is allowing simple waste processing techniques to be replicated all over the world, and helping make that information accessible is one of the most fulfilling aspects of my career.
“Give a man a fish and he can eat for a day. Show a man how to fish and he can eat for the rest of his life.” Teaching people how to make valuable products from waste is important. But just as important, is passing on the business skills to be able to identify a market, factor in costs, check out the competition, market their products and run a successful business.
Development work in the waste arena needs to address both sides of the coin, and in doing so will enable people to start up their own businesses, in their own communities, and generate wealth organically. That’s far more valuable than delivering aid in a ready-made package (which incidentally rarely works – there’s a great TED Talk on this topic by Ernesto Sirolli, called “Want to help someone? Shut up and listen”).
Why closing dumps isn’t a silver bullet
The proliferation of megacities, particularly in developing countries, is causing a health crisis. Decent waste management is an indicator of good governance – that is, if a council or government can collect taxes and provide a waste management service, then it most likely isn’t (very) corrupt. However, in many places where corruption or other forms of bad or weak governance prevail, top-down solutions are notoriously difficult to implement.
Often, when the world’s attention turns to an open dump, the government responds by closing it and the journalists go home. This is what happened with Smokey Mountain dumpsite in the Philippines (and many others around the world). All that happens is another open dump emerges nearby, and the scavengers move to the new site.
The problem is that if there is no alternative solution in place, people will discard of their waste in the only ways available – dumping it or burning it; and the poor will follow the waste.
Replacing an open dump with a government-controlled waste management system isn’t a silver bullet either. The losers, again, are the hundreds, and sometimes thousands of men, women and children who live from scavenging from the dump. It may seem horrific to many of us, but the truth is that if you take that opportunity to earn a paltry living away from the poorest in society, they will starve. Solutions need to be inclusive.
Power to the people
To close dump sites, you need to have a workable alternative solution in place. You need to have regular waste collection taking place, and you need somewhere to take it. Building materials recovery facilities alongside existing open dumps is one idea. Informal waste pickers who are currently working in dangerous conditions on the dumpsite can gain employment (or better still, form a cooperative) sorting recyclable materials and reducing the amount of real “waste” that needs to be disposed of.
For example, Wecyclers in Lagos, Nigeria employs people to cycle around collecting recyclable materials from households. In return for their source-separated waste, the householder receives a small reward.
In Bangalore, IGotGarbage has harnessed the power of phone apps to enable people who were previously waste pickers to be called directly to a house to collect the waste materials. Solutions like this work because they continue to provide livelihoods for people, while taking waste off the streets.
The need for appropriate technology
There will always be something left though: the stuff that really has little value other than the energy embodied in it. In industrialised countries, energy-from-waste incinerators have become popular. Seen as a clean alternative to landfill, these facilities burn the waste, release the energy, and convert it into heat, electricity and ash. Some of that ash (from the air pollution control system) still needs to be disposed of in specially-prepared hazardous waste landfill sites. The remainder, being fairly benign, can be used to make concrete building blocks.
However, incinerators are fairly technology-heavy, rendering them unsuitable for many developing country contexts.
A problem that we’ve witnessed is that waste management companies from industrialised nations try to wholesale their technology in developing countries. The technology is usually unaffordable, and even if the capital can be raised to procure a facility, as soon as something breaks down the whole solution can fall apart.
There is a need for information about simple waste processing technologies to become more open-sourced. Smart future-thinking businesses could capitalise on selling blueprints rather than entire prefabricated facilities. Most of the time it’s far cheaper to fabricate something locally, and also means that when something breaks it can be fixed.
The continuing need for landfill
The fact is that in most cases, a standard, lined landfill site with landfill gas capture is still the most appropriate answer for non-recyclable waste. Add to that a well-organised, low-cost waste collection service with source separation of recyclable materials and biodegradable waste, and you have a relatively affordable solution that is better for the climate, better for health, better for the local economy, and contributes to a more sustainable future.
Landfill may seem very unfashionable to those of us who work in the recycling sector, but nevertheless it will remain a necessity both in developed and developing countries for the foreseeable future.
Joining forces and stepping stones
The success of the Sustainable Development Goals and potential Climate Change Agreement depend on developed and developing countries working together. Miguel Arias Cañete, the EU climate commissioner, said the Climate Coalition alliance showed that developed and developing countries could work together with a common interest. “These negotiations are not about them and us. They are about all of us, developed and developing countries, finding common ground and solutions together. We urge other countries to join us. Together we can do it.”
Necessity is the mother of invention, and we are facing a waste crisis of unprecedented proportion. The potential for waste management in reducing GHG emissions has never been more pertinent. Waste and development practitioners, academics and entrepreneurs around the world are working together more and more to help bring about the change we want to see, which will benefit the billions of people suffering from poor waste management, and the rest of us who share a warming planet – and share the burden of climate change and poverty.
By sharing knowledge through platforms such as beWasteWise and ISWA, and through initiatives like WasteAid, WASTE and Wiego, we can start making a dent in this very large problem.
No silver bullets, but lots of small stepping stones in the right direction.
Note: The original and unabridged version of the article can be found at this link. Please visit http://zlcomms.co.uk/ for more information about the author.
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