Pyrolysis is rapidly developing biomass thermal conversion technology and has been garnering much attention worldwide due to its high efficiency and good eco-friendly performance characteristics. Pyrolysis technology provides an opportunity for the conversion of municipal solid wastes, agricultural residues, scrap tires, non-recyclable plastics etc into clean energy. It offers an attractive way of converting urban wastes into products which can be effectively used for the production of heat, electricity and chemicals.
Pyrolysis of Municipal Wastes
Pyrolysis process consists of both simultaneous and successive reactions when carbon-rich organic material is heated in a non-reactive atmosphere. Simply speaking, pyrolysis is the thermal degradation of organic materials in the absence of oxygen. Thermal decomposition of organic components in the waste stream starts at 350°C–550°C and goes up to 700°C–800°C in the absence of air/oxygen.
Pyrolysis of municipal wastes begins with mechanical preparation and separation of glass, metals and inert materials prior to processing the remaining waste in a pyrolysis reactor. The commonly used pyrolysis reactors are rotary kilns, rotary hearth furnaces, and fluidized bed furnaces. The process requires an external heat source to maintain the high temperature required.
Pyrolysis can be performed at relatively small-scale which may help in reducing transport and handling costs. In pyrolysis of MSW, heat transfer is a critical area as the process is endothermic and sufficient heat transfer surface has to be provided to meet process heat requirements.
The main products obtained from pyrolysis of municipal wastes are a high calorific value gas (synthesis gas or syngas), a biofuel (bio oil or pyrolysis oil) and a solid residue (char). Depending on the final temperature, MSW pyrolysis will yield mainly solid residues at low temperatures, less than 4500C, when the heating rate is quite slow, and mainly gases at high temperatures, greater than 8000C, with rapid heating rates. At an intermediate temperature and under relatively high heating rates, the main product is a liquid fuel popularly known as bio oil.
Wide Range of Products
Bio oil is a dark brown liquid and can be upgraded to either engine fuel or through gasification processes to a syngas and then biodiesel. Pyrolysis oil may also be used as liquid fuel for diesel engines and gas turbines to generate electricity.
Bio oil is particularly attractive for co-firing because it can be relatively easy to handle and burn than solid fuel and is cheaper to transport and store. In addition, bio oil is also a vital source for a wide range of organic compounds and specialty chemicals.
Syngas is a mixture of energy-rich gases (combustible constituents include carbon monoxide, hydrogen, methane and a broad range of other VOCs). The net calorific value (NCV) of syngas is between 10 and 20MJ/Nm3. Syngas is cleaned to remove particulates, hydrocarbons, and soluble matter, and then combusted to generate electricity.
Diesel engines, gas turbines, steam turbines and boilers can be used directly to generate electricity and heat in CHP systems using syngas and pyrolysis oil. Syngas may also be used as a basic chemical in petrochemical and refining industries.
The solid residue from MSW pyrolysis, called char, is a combination of non-combustible materials and carbon. Char is almost pure carbon and can be used in the manufacture of activated carbon filtration media (for water treatment applications) or as an agricultural soil amendment.
The Middle East and North Africa (MENA) region offers almost 45 percent of the world’s total energy potential from all renewable sources that can generate more than three times the world’s total power demand. Apart from solar and wind, MENA also has abundant bioenergy energy resources which have remained unexplored to a great extent.
Around the MENA region, pollution of the air and water from municipal, industrial and agricultural operations continues to grow. The technological advancements in the biomass energy and waste-to-energy industry, coupled with the tremendous regional potential, promises to usher in a new era of energy as well as environmental security for the region.
The major biomass producing countries in MENA are Saudi Arabia, Egypt, Yemen, Iraq, Syria and Jordan. Traditionally, biomass energy has been widely used in rural areas for domestic purposes in the MENA region, especially in Egypt, Yemen and Jordan. Since most of the region is arid or semi-arid, the major bioenergy resources are municipal solid wastes, agricultural residues and organic industrial wastes.
Municipal solid wastes represent the best source of biomass in Middle East countries. Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita solid waste generation. The gross urban waste generation quantity from Middle East countries is estimated at more than 150 million tons annually.
Food waste is the third-largest component of generated waste by weight which mostly ends up rotting in landfill and releasing greenhouse gases into the atmosphere. The mushrooming of hotels, restaurants, fast-food joints and cafeterias in the region has resulted in the generation of huge quantities of food wastes.
In Middle East countries, huge quantity of sewage sludge is produced on daily basis which presents a serious problem due to its high treatment costs and risk to environment and human health. On an average, the rate of wastewater generation is 80-200 litres per person each day and sewage output is rising by 25 percent every year. According to estimates from the Drainage and Irrigation Department of Dubai Municipality, sewage generation in the Dubai increased from 50,000 m3 per day in 1981 to 400,000 m3 per day in 2006.
The food processing industry in MENA produces a large number of organic residues and by-products that can be used as biomass energy sources. In recent decades, the fast-growing food and beverage processing industry has remarkably increased in importance in major countries of the region. Since the early 1990s, the increased agricultural output stimulated an increase in fruit and vegetable canning as well as juice, beverage, and oil processing in countries like Egypt, Syria, Lebanon and Saudi Arabia.
The MENA countries have strong animal population. The livestock sector, in particular sheep, goats and camels, plays an important role in the national economy of respective countries. Many millions of live ruminants are imported each year from around the world. In addition, the region has witnessed very rapid growth in the poultry sector. The biogas potential of animal manure can be harnessed both at small- and community-scale.
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 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 soon.
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 35 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 2017 national budget allocated SR 54 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. Saudi visa for qualified waste management professionals will also go a long way in improving waste management situation in the country.
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.
Historically, burying the wastes is the 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 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.
For the first time in the history of India, the year 2012 saw several public protests against improper solid waste management all across India – from the northernmost state Jammu and Kashmir to the southernmost Tamil Nadu. A fight for the right to clean environment and environmental justice led the people to large scale demonstrations, including an indefinite hunger strike and blocking roads leading to local waste handling facilities. Improper waste management has also caused a Dengue Fever outbreak and threatens other epidemics.
In recent years, solid waste management has been the only other unifying factor leading to public demonstrations all across India, after corruption and fuel prices. Public agitation resulted in some judicial action and the government’s remedial response, but the waste management problems are still unsolved and might lead to a crisis if this continues for too long without any long term planning and policy reforms.
Hunger Strike in Kerala
The President of Vilappilsala Village Panchayat went on a hunger strike recently, against her counterpart, the Mayor of Thiruvananthapuram. Thiruvananthapuram is the state capital of Kerala, and Vilappilsala is a village 22 km away.
Since July 2000, about 80% of the waste generated in Thiruvananthapuram is being transported to a waste composting plant and a dumpsite in Vilappilsala village. Since the same month, respiratory illnesses reported in Vilappil Primary Health Center increased by 10 times from an average of 450 to 5,000 cases per month. People who used to regularly swim in the village’s aquifer started contracting infections; swarms of flies have ever since been pervasive; and a stigma of filth affected households throughout the community. This was a source of frustration as locals who, as Indians, prize the opportunity to feed and host guests, found them unwilling to even drink a glass of water in their homes. Currently, there is not a single household which has not experienced respiratory illnesses due to the waste processing plant and the adjoining dumpsite.
On the other hand, Thiruvananthapuram’s residents had to sneak out at night with plastic bags full of trash to dispose them behind bushes, on streets or in water bodies, and had to openly burn heaps of trash every morning for months. This was because the waste generated was not being collected by the City as it could not force open the composting plant and dumpsite against large scale protests by Vilappilsala’s residents. This is why in August – 2012, about 2,500 police personnel had to accompany trucks to the waste treatment plant as they were being blocked by local residents lying down on the road, and by some, including the village’s President, by going on an indefinite hunger strike.
Municipal Commissioner Replaced in Karnataka
In response to a similar situation in Bengaluru, the state capital of Karnataka, where the streets were rotting with piles of garbage for months, the municipal commissioner of the city was replaced to specifically address the waste management situation. Against the will of local residents, a landfill which was closed following the orders issued by the state’s pollution control board in response to public agitation had to be reopened soon after its closure as the city could not find a new landfill site.
Mavallipura landfill in Bangalore
Population density and the scale of increasing urban sprawl in India make finding new landfill sites around cities nearly impossible due to the sheer lack of space for Locally Unwanted Land Uses (LULUs) like waste management.
Dengue Outbreak in West Bengal
Even if partially because of improper waste management, Kolkata, state capital of West Bengal and the third biggest city in India experienced a Dengue Fever outbreak with 550 confirmed cases and 60 deaths. This outbreak coincides with a 600% increase in dengue cases in India and 71% increase in malarial cases in Mumbai in the last five years.
Accumulation of rain water in non biodegradable waste littered around a city act as a major breeding environment for mosquitoes, thus increasing the density of mosquito population and making the transmission of mosquito related diseases like dengue, yellow fever and malaria easier.
Rabies in Srinagar
Rabies due to stray dog bites already kills more than 20,000 people in India every year. Improper waste management has caused a 1:13 stray dog to human ratio in Srinagar (compared to 1 per 31 people in Mumbai and 1 per 100 in Chennai), where 54,000 people were bitten by stray dogs in a span of 3.5 years. Municipal waste on streets and at the dumpsite is an important source of food for stray dogs.
The Kingdom of Saudi Arabia produces around 15 million tons of municipal solid waste (MSW) each year with average daily rate of 1.4 kg per person. With the current growing population (3.4% yearly rate), urbanization (1.5% yearly rate) and economic development (3.5% yearly GDP rate), the generation rate of MSW will become double (30 million tons per year) by 2033. The major ingredients of Saudi Arabian MSW are food waste (40-51 %), paper (12-28 %), cardboard (7 %), plastics (5-17 %), glass (3-5 %), wood (2-8 %), textile (2-6 %), metals (2-8 %) etc. depending on the population density and urban activities of that area.
In Saudi Arabia, MSW is collected and sent to landfills or dumpsites after partial segregation and recycling. The major portion of collected waste is ends up in landfills untreated. The landfill requirement is very high, about 28 million m3 per year. The problems of leachate, waste sludge, and methane and odor emissions are occurring in the landfills and its surrounding areas due to mostly non-sanitary or un-engineered landfills. However, in many cities the plans of new sanitary landfills are in place, or even they are being built by municipalities with capturing facilities of methane and leachate.
Recycling Prospects in Saudi Arabia
The recycling of metals and cardboard is the main waste recycling practice in Saudi Arabia, which covers 10-15% of the total waste. This recycling practice is mostly carried out by informal sector. The waste pickers or waste scavengers take the recyclables from the waste bins and containers throughout the cities. The waste recycling rate often becomes high (upto 30% of total waste) by waste scavengers in some areas of same cities. The recycling is further carried out at some landfill sites, which covers upto 40% of total waste by the involvement of formal and informal sectors.
The recycled products are glass bottles, aluminum cans, steel cans, plastic bottles, paper, cardboard, waste tire, etc. depending on the area, available facilities and involved stakeholders. It is estimated that 45 thousand TJ of energy can be saved by recycling only glass and metals from MSW stream. This estimation is based on the energy conservation concept, which means xyz amount of energy would be used to produce the same amount of recyclable material.
Waste-to-Energy Potential in Saudi Arabia
The possibilities of converting municipal wastes to renewable energy are plentiful. The choice of conversion technology depends on the type and quantity of waste (waste characterization), capital and operational cost, labor skill requirements, end-uses of products, geographical location and infrastructure. Several waste to energy technologies such as pyrolysis, anaerobic digestion (AD), trans-esterification, fermentation, gasification, incineration, etc. have been developed. Waste-to-energy provides the cost-effective and eco-friendly solutions to both energy demand and MSW disposal problems in Saudi Arabia.
As per conservative estimates, electricity potential of 3 TWh per year can be generated, if all of the KSA food waste is utilized in biogas plants. Similarly, 1 and 1.6 TWh per year electricity can be generated if all the plastics and other mixed waste (i.e. paper, cardboard, wood, textile, leather, etc.) of KSA are processed in the pyrolysis, and refuse derived fuel (RDF) technologies respectively.
Waste management issues in Saudi Arabia are not only related to water, but also to land, air and the marine resources. The sustainable integrated solid waste management is still at the infancy level. There have been many studies in identifying the waste related environmental issues in KSA. The current SWM activities of KSA require a sustainable and integrated approach with implementation of waste segregation at source, waste recycling, WTE and value-added product (VAP) recovery. By 2032, Saudi government is aiming to generate about half of its energy requirements (about 72 GW) from renewable sources such as solar, nuclear, wind, geothermal and waste-to-energy systems.
Waste management is a serious problem in Nigeria, and Delta State is no exception. It is a problem that starts at a cultural level: many of the populace believe that once they remove waste from their homes it is no longer their concern. It is a problem that starts at a cultural level: many of the populace believe that once they remove waste from their homes it is no longer their concern, and you often see people disposing of their household waste in the streets at night. Once the waste gets out into the streets, it’s perceived as the duty of the government to handle it.
However, I have never yet heard of any Nigerian politician making waste management a feature of his or her manifesto during the election campaign process. Having said that, a few of Nigeria’s political leaders deserve to be commended for coming to terms with the fact that waste has to be managed properly, even if such issues were far from their minds when they entered political office.
Legislation and Framework
Nigeria does have a waste legislation framework in place. Its focus has been on the most toxic and hazardous waste: partly in response to some major pollution incidents in the 1980s, the government took powers in relation to Hazardous Waste in 1988. In the same year, the Federal Environmental Protection Agency was established – and was subsequently strengthened by the addition of an inspectorate and enforcement department arm in 1991, with divisions for standard regulation, chemical tracking and compliance monitoring. These laws have since given rise to regulations and guidelines pertaining to environmental and waste management issues.
Under our laws, waste management in each state is the duty of the local governments that fall within it, but few are taking an active approach to implementing and enforcing the sensible measures that the regulations require. A small number of states have taken over this task from local government, and Delta State’s decision to do this has led to significant new investment in waste management.
One of the fruits of that investment is the Delta State Integrated Waste Management Facility at Asaba for treating both household and clinical waste generated locally. It was developed when the Delta State government decided to put an end to the non-sustainable dumping of waste in Asaba, the state capital.
Integrated Waste Management Facility at Asaba
It is described as an integrated waste management facility because it includes a composting department, a recycling department and a (non-WTE) incineration department. Trucks carrying waste are weighed in as they come into the facility. From the weigh bridge, they move to the relevant reception bay – there are separate ones for household and clinical wastes – to tip their load, and are then weighed again on the way out.
Medical waste is taken directly for incineration, but household wastes are sent along conveyors for sorting. Recyclables and compostable materials are, so far as possible, separated both from other waste and from one another. Each recyclable stream ends up in a chamber where it can be prepared for sale. The compostable materials are moved to the composting section, which uses aerated static pile composting.
The remaining waste is conveyed into the three incinerators – moving grate, rotary kiln and fixed end– for combustion. The resulting ash is recycled by mixing it with cement and sharp sand and moulding it into interlocking tiles. The stacks of the three incinerators are fitted with smoke cleaning systems to reduce emissions. The process produces wastewater, which is channelled to a pit where it is treated and reused. Overall, 30% of the waste is composted, 15% recycled and 55% incinerated.
There are many examples of sophisticated waste infrastructure being built in developing countries, but failing because the necessary collection systems were not in place to support them. To ensure that this problem is avoided at Asaba, the Delta State government is working with a group known as the Private Sector Participants (PSP).
Each member of this group has trucks assigned to them and has been directed to collect household waste from different parts of the city, for delivery to the facility for treatment. The arrangements made by each PSP are different: some collect from outside individual properties, and some from communal sites; most collect waste that is found in the streets; and while each is subsidised by the state, households also have to pay towards the cost.
Before the Asaba waste management facility was developed, most of the wastes generated in Asaba were disposed of at a dumpsite just adjacent to the Delta State Airport. This created a pungent odour, as well as visual disamenity for people nearby. A great deal of remediation work is now taking place at the dumpsite, which is vastly improving the local environmental quality.
War on Waste
Of course, although this is an improvement there remains more to do. First on the list is education. People do not know how sustainable waste management can impact positively in their lives, reducing their exposure to toxins as well as improving their surroundings. Nor do they understand that recycling a beverage can or a plastic bottle will cost less than producing one from virgin materials and will have a lesser environmental impact. There remains a good deal of cultural change and environmental education that is needed before people will stop throwing waste and litter on the streets – but there are few countries where, to some extent, the same would not be true.
Next is the lack of infrastructure. Nigeria has 36 states and a federal capital, yet the facility in Asaba is the first publicly commissioned one of its kind in the country; there are also some privately owned incinerators that a few companies in Port Harcourt use to treat wastes from vessels (ships), hospitals and industries. Lagos state and Abuja are relatively advanced, simply by virtue of having put in place a few managed landfills, but they are still far from having the level of facility that Asaba can now boast.
The backbone of Asaba’s progress is the state government’s commitment to put a proper waste management solution in place. We’ve seen the impact in the form of infrastructure, collections and remediation, and law enforcement work is starting to change people’s perception about waste management in Delta State. At the moment, plans are being concluded to setup another facility in Warri, Delta State’s industrial hub, which will be twice the size of the Asaba facility.?
My hope is that the progress made by Delta State will be a beacon for other states’ governments. The example we are providing of cleaner, hygienic, more environmentally responsible waste management, and the positive changes that is bringing about, should inspire new development elsewhere in the country, which could equal or even exceed Delta State’s results. So whilst Nigeria’s track record on waste may leave a lot to be desired, the path ahead could be a great deal more promising.
Note: The article is being republished with the kind permission of our collaborative partner Isonomia. The original article can be found at this link.
It is estimated that Indonesia produces 146.7 million tons of biomass per year, equivalent to about 470 GJ/y. Sources of biomass energy in Indonesia are scattered all over the country, but the biggest biomass energy potential in concentrated scale can be found in the Island of Kalimantan, Sumatera, Irian Jaya and Sulawesi.
Studies estimate the electricity generation potential from the roughly 150 Mt of biomass residues produced per year to be about 50 GW or equivalent to roughly 470 GJ/year. These studies assume that the main source of biomass energy in Indonesia will be rice residues with a technical energy potential of 150 GJ/year.
Other potential biomass sources are rubber wood residues (120 GJ/year), sugar mill residues (78 GJ/year), palm oil residues (67 GJ/year), and less than 20 GJ/year in total from plywood and veneer residues, logging residues, sawn timber residues, coconut residues, and other agricultural wastes.
Sustainable and renewable natural resources such as biomass can supply potential raw materials for energy conversion. In Indonesia, they comprise variable-sized wood from forests (i.e. natural forests, plantations and community forests that commonly produce small-diameter logs used as firewood by local people), woody residues from logging and wood industries, oil-palm shell waste from crude palm oil factories, coconut shell wastes from coconut plantations, as well as skimmed coconut oil and straw from rice cultivation.
The major crop residues to be considered for power generation in Indonesia are palm oil, sugar processing and rice processing residues. Currently, 67 sugar mills are in operation in Indonesia and eight more are under construction or planned. The mills range in size of milling capacity from less than 1,000 tons of cane per day to 12,000 tons of cane per day. Current sugar processing in Indonesia produces 8 millions MT bagasse and 11.5 millions MT canes top and leaves.
There are 39 palm oil plantations and mills currently operating in Indonesia, and at least eight new plantations are under construction. Most palm oil mills generate combined heat and power from fibres and palm kernel shells, making the operations energy self–efficient. However, the use of palm oil residues can still be optimized in more energy efficient systems.
Other potential source of biomass energy can also come from municipal wastes. The quantity of city or municipal wastes in Indonesia is comparable with other big cities of the world. Most of these wastes are originated from household in the form of organic wastes from the kitchen. At present the wastes are either burned at each household or collected by the municipalities and later to be dumped into a designated dumping ground or landfill.
Although the government is providing facilities to collect and clean all these wastes, however, due to the increasing number of populations coupled with inadequate number of waste treatment facilities in addition to inadequate amount of allocated budget for waste management, most of big cities in Indonesia had been suffering from the increasing problem of waste disposals.
With Indonesia’s recovery from the Asian financial crisis of 1998, energy consumption has grown rapidly in past decade. The priority of the Indonesian energy policy is to reduce oil consumption and to use renewable energy. For power generation, it is important to increase electricity power in order to meet national demand and to change fossil fuel consumption by utilization of biomass wastes. The development of renewable energy is one of priority targets in Indonesia.
The current pressure for cost savings and competitiveness in Indonesia’s most important biomass-based industries, along with the continually growing power demands of the country signal opportunities for increased exploitation of biomass wastes for power generation.
Composting in Qatar is mainly done at the Domestic Solid Waste Management Centre (DSWMC) in Mesaieed, which houses the largest composting facility in the country and one of the largest in the world. The waste that enters the plant initially goes through anaerobic digestion, which produces biogas that can power the facility’s gas engine and generators, followed by aerobic treatment which yields the final product.
Two types of compost are generated: Grade A (compost that comes from green waste, such as yard/park trimmings, leftovers from kitchen or catering services, and wastes from markets) and Grade B (compost produced from MSW). The plant started its operation in 2011 and when run at full capacity is able to process 750 tons of waste and produce 52 tons of Grade A compost, 377 tons of Grade B compost, liquid fertilizer which is composed of 51 tons of Grade A compost and 204 tons of Grade B compost, and 129 tons of biogas.
This is a significant and commendable development in Qatar’s implementation of its solid waste management plan, which is to reduce, reuse, recycle and recover from waste, and to avoid disposing in landfills as much as possible. However, the large influx of workers to Qatar in the coming years as the country prepares to host the World Cup in 2022 is expected to substantially increase solid waste generation and apart from its investments in facilities like the composting plant and in DSWMC in general, the government may have to tap into the efforts of organizations and communities to implement its waste management strategy.
Thankfully, several organizations recognize the importance of composting in waste management and are raising awareness on its benefits. Qatar Green Building Council (QGBC) has been actively promoting composting through its Solid Waste Interest Group. Last year, they were one of the implementers of the Baytna project, the first Passivhaus experiment in the country.
This project entails the construction of an energy-efficient villa and a comparative study will be performed as to how the carbon footprint of this structure would compare to a conventional villa. The occupants of the Passivhaus villa will also be made to implement a sustainable waste management system which includes composting of food waste and garden waste, which is meant to lower greenhouse gas emissions compared to landfilling.
Qatar Foundation is also currently developing an integrated waste management system for the entire Education City and the Food Services group is pushing for composting to be included as a method to treat food and other organic waste. And many may not know this but composting can be and has been done by individuals in their own backyard and can even be done indoors with the right equipment.
Katrin Scholz-Barth, previous president of SustainableQatar, a volunteer-based organization that fosters sustainable culture through awareness, skills and knowledge, is an advocate of composting and has some great resources on how to start and maintain your own composting bin as she has been doing it herself.
A simple internet search will also reveal that producing compost at home is a relatively simple process that can be achieved with minimal tools. At present, very few families in Qatar are producing their own compost and Scholz-Barth believes there is much room for improvement.
It would also be worthwhile to include programs that will promote and boost composting efforts among institutions, organizations and individuals, encouraging them with the fact that apart from its capability of significant waste diversion from landfills, composting can also be an attractive source of income.
Note: The article is being republished with the permission of our collaborative partner EcoMENA. The original article can be viewed at this link.
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