Tag Archives: Municipal Solid Wastes

Municipal Solid Wastes in Bahrain

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Bahrain has the distinction of being one of the highest per capita municipal solid waste generators worldwide estimated to be more than 1.80 kg per person per day. Infact, Bahrain produces largest amount of waste per person among GCC countries despite being the smallest nation in the region. Rising population, high waste generation growth rate, limited land availability and scarcity of waste disposal sites has made solid waste management a highly challenging task for Bahrain’s policy-makers, urban planners and municipalities.

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Municipal Solid Wastes in Bahrain

Bahrain generates more than 1.2 million tons of solid wastes every year. Daily garbage production across the tiny Gulf nation exceeds 4,500 tons. Municipal solid waste is characterized by high percentage of organic material (around 60 percent) which is mainly composed of food wastes. Presence of high percent of recyclables in the form of paper (13 percent), plastics (7 percent) and glass (4 percent) makes Bahrain’s MSW a good recycling feedstock, though informal sectors are currently responsible for collection of collection of recyclables and recycling activities

The Kingdom of Bahrain is divided into five governorates namely Manama, Muharraq, Middle, Southern and Northern. Waste collection and disposal operation in Bahrain is managed by a couple of private contractors. Gulf City Cleaning Company is active in Muharraq and Manama while Sphinx Services is responsible for Southern, Middle, and Northern Areas. The prevalent solid waste management scenario is to collect solid waste and dump it at the municipal landfill site at Askar.

Askar, the only existing landfill/dumpsite in Bahrain, caters to municipal wastes, agricultural wastes and non-hazardous industrial wastes. Spread over an area of more than 700 acres, the landfill is expected to reach its capacity within the next few years. The proximity of Askar landfill to urban habitats has been a cause of major environmental concern. Waste accumulation is increasing at a rapid pace which is bound to have serious impacts on air, soil and groundwater quality in the surrounding areas.

Conclusions

The Kingdom of Bahrain is grappling with waste management problems arising out of high population growth rate, rapid industrialization, high per capita waste generation, unorganized SWM sector, limited land resources and poor public awareness.

The government is trying hard to improve waste management scenario by launching recycling initiatives, waste-to-energy project and public awareness campaign. However more efforts, in the form of effective legislation, large-scale investments, modern SWM technology deployment and environmental awareness, are required from all stake holders to implement a sustainable waste management system in Bahrain.

Pelletization of Municipal Solid Wastes

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MSW is a poor-quality fuel and its pre-processing is necessary to prepare fuel pellets to improve its consistency, storage and handling characteristics, combustion behaviour and calorific value. Technological improvements are taking place in the realms of advanced source separation, resource recovery and production/utilisation of recovered fuel in both existing and new plants for this purpose. There has been an increase in global interest in the preparation of RDF containing a blend of pre-processed MSW with coal suitable for combustion in pulverised coal and fluidised bed boilers.

RDF

Pelletization of municipal solid waste involves the processes of segregating, crushing, mixing high and low heat value organic waste material and solidifying it to produce fuel pellets or briquettes, also referred to as Refuse Derived Fuel (RDF). The process is essentially a method that condenses the waste or changes its physical form and enriches its organic content through removal of inorganic materials and moisture. The calorific value of RDF pellets can be around 4000 kcal/ kg depending upon the percentage of organic matter in the waste, additives and binder materials used in the process.

The calorific value of raw MSW is around 1000 kcal/kg while that of fuel pellets is 4000 kcal/kg. On an average, about 15–20 tons of fuel pellets can be produced after treatment of 100 tons of raw garbage. Since pelletization enriches the organic content of the waste through removal of inorganic materials and moisture, it can be very effective method for preparing an enriched fuel feed for other thermochemical processes like pyrolysis/ gasification, apart from incineration.

Pellets can be used for heating plant boilers and for the generation of electricity. They can also act as a good substitute for coal and wood for domestic and industrial purposes. The important applications of RDF are found in the following spheres:

  • Cement kilns
  • RDF power plants
  • Coal-fired power plants
  • Industrial steam/heat boilers
  • Pellet stoves

The conversion of solid waste into briquettes provides an alternative means for environmentally safe disposal of garbage which is currently disposed off in non-sanitary landfills. In addition, the pelletization technology provides yet another source of renewable energy, similar to that of biomass, wind, solar and geothermal energy. The emission characteristics of RDF are superior compared to that of coal with fewer emissions of pollutants like NOx, SOx, CO and CO2.

RDF production line consists of several unit operations in series in order to separate unwanted components and condition the combustible matter to obtain the required characteristics. The main unit operations are screening, shredding, size reduction, classification, separation either metal, glass or wet organic materials, drying and densification. These unit operations can be arranged in different sequences depending on raw MSW composition and the required RDF quality.

Various qualities of fuel pellets can be produced, depending on the needs of the user or market. A high quality of RDF would possess a higher value for the heating value, and lower values for moisture and ash contents. The quality of RDF is sufficient to warrant its consideration as a preferred type of fuel when solid waste is being considered for co-firing with coal or for firing alone in a boiler designed originally for firing coal.

Biomass Resources in Malaysia

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Malaysia is gifted with conventional energy resources such as oil and gas as well as renewables like hydro, biomass and solar energy. As far as biomass resources in Malaysia are concerned, Malaysia has tremendous agricultural biomass and wood waste resources available for immediate exploitation. This energy potential of biomass resource is yet to be exploited properly in the country.

Taking into account the growing energy consumption and domestic energy supply constraints, Malaysia has set sustainable development and diversification of energy sources, as the economy’s main energy policy goals. The Five-Fuel Strategy recognises renewable energy resources as the economy’s fifth fuel after oil, coal, natural gas and hydro. Being a major agricultural commodity producer in the region Malaysia is well positioned amongst the ASEAN countries to promote the use of biomass as a source of renewable energy.

Major Biomass Resources in Malaysia

  • Agricultural crops e.g. sugarcane, cassava, corn
  • Agricultural residues e.g. rice straw, cassava rhizome, corncobs
  • Woody biomass e.g. fast-growing trees, wood waste from wood mill, sawdust
  • Agro-Industrial wastes e.g. rice husks from rice mills, molasses and bagasse from sugar refineries, residues from palm oil mills
  • Municipal solid waste
  • Animal manure and poultry litter

Palm Oil Biomass

Malaysia is the world’s leading exporter of palm oil, exporting more than 19.9 million tonnes of palm oil in 2017. The extraction of palm oil from palm fruits results in a large quantity of waste in the form of palm kernel shells, empty fruit bunches and mesocarp fibres. In 2011, more than 80 million tons of oil palm biomass was generated across the country.

13MW biomass power plant at a palm oil mill in Sandakan, Sabah (Malaysia)

Processing crude palm oil generates a foul-smelling effluent, called Palm Oil Mill Effluent or POME, which when treated using anaerobic processes, releases biogas. Around 58 million tons of POME is produced in Malaysia annually, which has the potential to produce an estimated 15 billion m3 of biogas.

Rice Husk

Rice husk is another important agricultural biomass resource in Malaysia with very good energy potential for biomass cogeneration. An example of its attractive energy potential is biomass power plant in the state of Perlis which uses rice husk as the main source of fuel and generates 10 MW power to meet the requirements of 30,000 households.

Municipal Solid Wastes

The per capita generation of solid waste in Malaysia varies from 0.45 to 1.44kg/day depending on the economic status of an area. Malaysian solid wastes contain very high organic waste and consequently high moisture content and bulk density of above 200kg/m3. The high rate of population growth is the country has resulted in rapid increase in solid waste generation which is usually dumped in landfills.

Conclusion

Biomass resources have long been identified as sustainable source of renewable energy particularly in countries where there is abundant agricultural activities. Intensive use of biomass as renewable energy source in Malaysia could reduce dependency on fossil fuels and significant advantage lies in reduction of net carbon dioxide emissions to atmosphere leading to less greenhouse effect. However, increased competitiveness will require large-scale investment and advances in technologies for converting this biomass to energy efficiently and economically.

Bioenergy in Southeast Asia: Perspectives

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Southeast Asia, with its abundant bioenergy resources, holds a strategic position in the global biomass energy atlas. There is immense biomass energy potential in Southeast Asian countries due to plentiful supply of diverse forms of biomass wastes, such as agricultural residues, woody biomass, animal wastes, municipal solid waste, etc. The rapid economic growth and industrialization in the region has accelerated the drive to implement the latest waste-to-energy technologies to tap the unharnessed potential of biomass resources.

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Southeast Asia is a big producer of agricultural and wood products which, when processed in industries, produces large amounts of biomass residues. According to conservative estimates, the amount of biomass residues generated from sugar, rice and palm oil mills is more than 200-230 million tons per year which corresponds to cogeneration potential of 16-19 GW.

Rice mills in the region produce 38 million tonnes of rice husk as solid residue which is a good fuel for producing heat and power. Sugar industry is an integral part of the industrial scenario in Southeast Asia accounting for 7% of sugar production worldwide. Sugar mills in Thailand, Indonesia, Philippines and Vietnam generate 34 million tonnes of bagasse every year.  Malaysia, Indonesia and Thailand account for 90% of global palm oil production leading to the generation of 27 million tonnes of waste per annum in the form of empty fruit bunches (EFBs), fibers and shells, as well as liquid effluent.

Woody biomass is a good energy resource due to presence of large number of forests in Southeast Asia. Apart from natural forests, non-industrial plantations of different types (e.g. coconut, rubber and oil palm plantations, fruit orchards, and trees in homesteads and gardens) have gained recognition as important sources of biomass. In addition, the presence of a large number of wood processing industries also generates significant quantity of wood wastes. The annual production of wood wastes in the region is estimated to be more than 30 million m3.

The prospects of biogas power generation are also high in the region, thanks to presence of well-established food-processing and dairy industries. Another important biomass resource is contributed by municipal solid wastes in heavily populated urban areas.  In addition, there are increasing efforts both commercially and promoted by governments to develop biomass energy systems for efficient biofuel production, e.g. bio-diesel from palm oil.

Biomass resources, particularly residues from forests, wood processing, agricultural crops and agro-processing, are under-utilised in Southeast Asian countries. There is an urgent need to utilize biomass wastes for commercial electricity and heat production to cater to the needs of the industries as well as urban and rural communities.

Southeast Asian countries are yet to make optimum use of the additional power generation potential from biomass waste resources which could help them to partially overcome the long-term problem of energy supply. Technologies for biomass utilization which are at present widely used in Southeast counties need to be improved towards best practice by making use of the latest trends in the biomass energy sector.

Waste Management in Peshawar

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Peshawar is among the biggest cities in Pakistan with estimated population of 4 million inhabitants. Like most of the cities in Pakistan, solid waste management is a big challenge in Peshawar as the city generate 600-700 tons of municipal waste every day, with per capita generation of about 0.3 to 0.4 kg per day. Major part of the Peshawar population belongs to low and middle income area and based upon this fact, waste generation rate per capita varies in different parts of the city.

peshawar

Municipal solid waste collection and disposal services in the city are poor as approximately 60 per cent of the solid wastes remain at collection points, or in streets, where it emits a host of pollutants into the air, making it unacceptable for breathing. A significant fraction of the waste is dumped in an old kiln depression around the southern side of the city where scavengers, mainly comprising young children, manually sort out recyclable materials such as iron, paper, plastics, old clothes etc.

Peshawar has 4 towns and 84 union councils (UCs). Solid waste management is one of their functions. Now city government has planned to build a Refuse Derived Fuel (RDF), Composting Plant and possibly a Waste to Energy Power Plant which would be a land mark of Peshawar city administration.

The UCs are responsible for door to door collection of domestic waste and a common shifting practice with the help of hand carts to a central pick-up points in the jurisdiction of each UC. Town Council is responsible for collection and transporting the mixed solid waste to the specified dumps which ends up at unspecified depressions, agricultural land and roadside dumps.

Open dumping of municipal wastes is widely practiced in Peshawar

Presently, there are two sites namely Hazar Khwani and Lundi Akhune Ahmed which are being used for the purpose of open dumping. Waste scavenging is a major activity of thousands of people in the city. An alarming and dangerous practice is the burning of the solid waste in open dumps by scavengers to obtain recyclables like glass and metals.

Almost 50 percent of recyclables are scavenged at transfer stations from the waste reaching at such points. The recyclable ratio that remains in the house varies and cannot be recovered by the authorities unless it is bought directly from the households. Only the part of recyclables reaching a certain bin or secondary transfer station can be exploited.

In some areas of city where waste is transported by private companies from transfer points to the disposal site out study found that scavengers could only get about 35% of the recyclables from the waste at transfer station. Considering the above fact, it can be inferred that in case municipality introduces efficient waste transfer system in the city, the amount of recyclables reaching the disposal facility may increase by 30% of the current amount. In case house-to-house collection is introduced the municipality will be able to take hold of 90% of the recyclables in the waste stream being generated from a household.

Energy from Biomass Wastes in MENA

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The high volatility in oil prices in the recent past and the resulting turbulence in energy markets has compelled many MENA countries, especially the non-oil producers, to look for alternate sources of energy, for both economic and environmental reasons. The significance of renewable energy has been increasing rapidly worldwide due to its potential to mitigate climate change, to foster sustainable development in poor communities, and augment energy security and supply.

The MENA region is well-poised for biomass waste-to-energy development, with its rich feedstock base in the form of municipal solid wastes, crop residues and agro-industrial wastes. The high rate of population growth, urbanization and economic expansion in the Middle East is not only accelerating consumption rates but also accelerating the generation of a wide variety of waste.

Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita waste generation. The gross urban waste generation quantity from Arab countries is estimated at more than 80 million tons annually. Open dumping is the most prevalent mode of municipal solid waste disposal in most countries.

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Many Middle East nations lack legislative framework and regulations to deal with urban wastes.

Waste-to-energy technologies hold the potential to create renewable energy from biomass waste in the MENA region. Besides recovery of substantial energy, these technologies can lead to a substantial reduction in the overall waste quantities requiring final disposal, which can be better managed for safe disposal in a controlled manner. Waste-to-energy systems can contribute substantially to GHG mitigation through both reductions of fossil carbon emissions and long-term storage of carbon in biomass wastes.

Modern waste-to-energy systems options offer significant, cost-effective and perpetual opportunities for greenhouse gas emission reductions. Additional benefits offered are employment creation in rural areas, reduction of a country’s dependency on imported energy carriers (and the related improvement of the balance of trade), better waste control, and potentially benign effects with regard to biodiversity, desertification, recreational value, etc.

In summary, waste-to-energy can significantly contribute to sustainable development both in developed and less developed countries. Waste-to-energy is not only a solution to reduce the volume of waste that is and provide a supplemental energy source, but also yields a number of social benefits that cannot easily be quantified.

Biomass wastes in MENA can be efficiently converted into energy and fuels by biochemical and thermal conversion technologies, such as anaerobic digestion, gasification and pyrolysis. Waste-to-energy technologies hold the potential to create renewable energy from waste matter.

The implementation of waste-to-energy technologies as a method for safe disposal of solid and liquid biomass wastes, and as an attractive option to generate heat, power and fuels, can significantly reduce environmental impacts of wastes in the MENA region. In fact, energy recovery from MSW is rapidly gaining worldwide recognition as the fourth ‘R’ in sustainable waste management system – Reuse, Reduce, Recycle and Recover.

A transition from conventional waste management system to one based on sustainable practices is necessary to address environmental concerns and to foster sustainable development in the region.