Tag Archives: Municipal Solid Wastes

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.

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

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 Perspectives for Southeast Asia

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Southeast Asia, with its abundant bioenergy resources, holds a strategic position in the global biomass energy atlas. There is immense bioenergy 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.

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.

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

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

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

Open dumping of municipal wastes is widely practiced in Peshawar

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

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

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

SWM in India – Role of Policies and Planning

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Out of all the measures that are necessary in addressing India’s impending waste management crisis, the most efficient will be changes at the national policy and planning level. It is well known among the small but growing waste management sector that urban India will hit rock bottom due to improper waste management.

Solid-Wastes-Management-India

Unfortunately, they think such a crisis is required to bring about policy changes, as they generally tend to happen only after the damage has been done. This attitude is unfortunate because it indicates a lack of or failed effort from the sector to change policy, and also the level of India’s planning and preparedness.

Important Statistics

An average of 32,000 people will be added to urban India every day, continuously, until 2021. This number is a warning, considering how India’s waste management infrastructure went berserk trying to deal with just 25,000 new urban Indians during the last decade. The scale of urbanization in India and around the world is unprecedented with planetary consequences to Earth’s limited material and energy resources, and its natural balance.

Rate of increase in access to sanitation infrastructure generally lags behind the rate of urbanization by 33% around the world; however, the lack of planning and impromptu piecemeal responses to waste management issues observed in India might indicate a much wider gap. This means urban Indians will have to wait longer than an average urban citizen of our world for access to proper waste management infrastructure.

The clear trend in the outbreak of epidemic and public protests around India is that they are happening in the biggest cities in their respective regions. Kolkata, Bengaluru, Thiruvananthapuram, and Srinagar are capitals of their respective states, and Coimbatore is the second largest city in Tamil Nadu. However, long term national level plans to improve waste management in India do not exist and guidance offered to urban local bodies is meager.

Apart from the Jawaharlal Nehru National Urban Renewal Mission (JnNURM), there has been no national level effort required to address the problem. Even though JnNURM was phenomenal in stimulating the industry and local governments, it was not enough to address the scale and extent of the problem. This is because of JnNURM is not a long term financing program, sorts of which are required to tackle issues like solid waste management.

Role of Municipal Corporations

In the short term, municipal corporations have their hands tied and will not be able to deliver solutions immediately. They face the task of realizing waste management facilities inside or near cities while none of their citizens want them near their residences. Officials of Hyderabad’s municipal corporation have been conducting interviews with locals for about eight years now for a new landfill site, to no avail.

In spite of the mounting pressure, most corporations will not be able to close the dumpsites that they are currently using. This might not be the good news for which local residents could be waiting, but, it is important that bureaucrats, municipal officials and politicians be clear about it. Residents near Vellalore dump protested and blocked roads leading to the site because Coimbatore municipal officials repeatedly failed to fulfill their promises after every landfill fire incident.

Due to lack of existing alternatives, other than diverting waste fractionally by increasing informal recycling sector’s role, closing existing landfills would mean finding new sites. Finding new landfills in and around cities is nearly impossible because of the track record of dumpsite operations and maintenance in India and the Not in My Backyard (NIMBY) phenomenon.

However, the corporations can and should take measures to reduce landfill fires and open burning, and control pollution due to leachate and odor and vector nuisance. This will provide much needed relief to adjacent communities and give the corporations time to plan better. While navigating through an issue as sensitive this, it is of the utmost importance that they work closely with the community by increasing clarity and transparency.

Municipal officials at the meeting repeatedly stressed the issue of scarcity of land for waste disposal, which led to overflowing dumpsites and waste treatment facilities receiving more waste than what they were designed for. Most municipal officials are of the sense that a magic solution is right around the corner which will turn all of their city’s waste into fuel oil or gas, or into recycled products.

While such conversion is technologically possible with infinite energy and financial sources, that is not the reality. Despite their inability to properly manage wastes, the majority of municipal officials consider waste as “wealth” when approached by private partners. Therefore, a significant portion of officials expect royalty from private investments without sharing business risk.

Good News on the Horizon

While the situation across India is grim and official action has to be demanded through courts or public protests, there are a handful of local governments which are planning ahead and leading the way. The steps taken to solve New Delhi’s waste management problem is laudable. If it was not for the kind of leadership and determination showcased in Delhi, India would not have had its only operating WTE plant. This plant was built in 2011, at a time when the need for waste-to-energy plants was being felt all over India. 1300 tons of Delhi’s waste goes into this facility every day to generate electricity. The successful operation of this facility reinvigorated dormant projects across the nation.

After living with heaps of garbage for months, Thiruvananthapuram Municipal Corporation started penalizing institutions which dump their waste openly. It has also increased the subsidy on the cost of small scale biogas units to 75% and aerobic composting units to 90% to encourage decentralized waste management. The corporation is optimistic with the increase in number of applications for the subsidy from 10 in an entire year to 18 in just a few months after the announcement.

In Bengaluru, improper waste management led to the change of the city’s municipal commissioner. The new commissioner was handed over the job to particularly improve waste management in the city. As a response to the dengue outbreak in Kolkata, the state’s Chief Minister went door to door to create awareness about waste management, and also included the topic in her public speeches. For good or bad, many cities in India have started or initiated steps for banning plastics without performing life cycle analyses.

Municipal Solid Wastes in Bahrain

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The Kingdom of Bahrain is an archipelago of around 33 islands, the largest being the Bahrain Island. The population of Bahrain is around 1.2 million marked by population density of 900 persons per km2, which is the highest in the entire GCC region. The country has the distinction of being one of the highest per capita municipal solid waste generators worldwide estimated to be 1.67 – 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.

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.

Biomass Energy in Vietnam

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Vietnam is one of the few countries having a low level of energy consumption in the developing world with an estimated amount of 210 kg of oil equivalent per capita/year. Over half of the Vietnamese population does not have access to electricity. Vietnam is facing the difficult challenge of maintaining this growth in a sustainable manner, with no or minimal adverse impacts on society and the environment.

Being an agricultural country, Vietnam has very good biomass energy potential. Agricultural wastes are most abundant in the Mekong Delta region with approximately 50% of the amount of the whole country and Red River Delta with 15%. Major biomass resources includes rice husk from paddy milling stations, bagasse from sugar factories, coffee husk from coffee processing plants in the Central Highlands and wood chip from wood processing industries. Vietnam has set a target of having a combined capacity of 500 MW of biomass power by 2020, which is raised to 2,000 MW in 2030.

Rice husk and bagasse are the biomass resources with the greatest economic potential, estimated at 50 MW and 150 MW respectively. Biomass fuels sources that can also be developed include forest wood, rubber wood, logging residues, saw mill residues, sugar cane residues, bagasse, coffee husk and coconut residues. Currently biomass is generally treated as a non-commercial energy source, and collected and used locally. Nearly 40 bagasse-based biomass power plants have been developed with a total designed capacity of 150 MW but they are still unable to connect with the national grid due to current low power prices. Five cogeneration systems selling extra electricity to national grid at average price of 4UScents/kWh.

Biogas energy potential is approximately 10 billion m3/year, which can be collected from landfills, animal excrements, agricultural residues, industrial wastewater etc. The biogas potential in the country is large due to livestock population of more than 30 million, mostly pigs, cattle, and water buffalo. Although most livestock dung already is used in feeding fish and fertilizing fields and gardens, there is potential for higher-value utilization through biogas production. It is estimated that more than 25,000 household biogas digesters with 1 to 50 m3, have been installed in rural areas. The Dutch-funded Biogas Program operated by SNV Vietnam constructed some 18,000 biogas facilities in 12 provinces between 2003 and 2005, with a second phase (2007-2010) target of 150,000 biogas tanks in both rural and semi-urban settings.

Municipal solid waste is also a good biomass resource as the amount of solid waste generated in Vietnam has been increasing steadily over the last few decades. In 1996, the average amount of waste produced per year was 5.9 million tons per annum which rose to 28 million tons per in 2008 and expected to reach 44 million tons per year by 2015.