Tag Archives: Landfills

Renewable Energy from Food Residuals

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Food residuals are an untapped renewable energy source that mostly ends up rotting in landfills, thereby releasing greenhouse gases into the atmosphere. Food residuals are difficult to treat or recycle since it contains high levels of sodium salt and moisture, and is mixed with other waste during collection. Major generators of food wastes include hotels, restaurants, supermarkets, residential blocks, cafeterias, airline caterers, food processing industries, etc.

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According to EPA, about 63.1 million tons of food waste was thrown away into landfills or incinerators the United States in 2018. As far as United Kingdom is concerned, households threw away 6.6 million tons of food each year. These statistics are an indication of tremendous amount of food waste generated all over the world.

The proportion of food residuals in municipal waste stream is gradually increasing and hence a proper food waste management strategy needs to be devised to ensure its eco-friendly and sustainable disposal. Currently, only about 3 percent of food waste is recycled throughout U.S., mainly through composting. Composting provides an alternative to landfill disposal of food waste, however it requires large areas of land, produces volatile organic compounds and consumes energy. Consequently, there is an urgent need to explore better recycling alternatives.

Anaerobic digestion has been successfully used in several European and Asian countries to stabilize food wastes, and to provide beneficial end-products. Sweden, Austria, Denmark, Germany and England have led the way in developing new advanced biogas technologies and setting up new projects for conversion of food waste into energy.

Anaerobic Digestion of Food Waste

Anaerobic digestion is the most important method for the treatment of organic waste, such as food residuals, because of its techno-economic viability and environmental sustainability. Anaerobic digestion generates renewable energy from food waste  in the form of biogas and preserves the nutrients which are recycled back to the agricultural land in the form of slurry or solid fertilizer.

The relevance of biogas technology lies in the fact that it makes the best possible use of various organic wastes as a renewable source of clean energy. A biogas plant is a decentralized energy system, which can lead to self-sufficiency in heat and power needs, and at the same time reduces environmental pollution. Thus, anaerobic digestion of food waste can lead to climate change mitigation, economic benefits and landfill diversion opportunities.

Of the different types of organic wastes available, food waste holds the highest potential in terms of economic exploitation as it contains high amount of carbon and can be efficiently converted into biogas and organic fertilizer. Food waste can either be used as a single substrate in a biogas plant, or can be co-digested with organic wastes like cow manure, poultry litter, sewage, crop residues, slaughterhouse wastes, etc.

Renewable Energy from Food Residuals

The feedstock for the food waste-to-energy plant includes leftover food, vegetable refuse, stale cooked and uncooked food, meat, tea bags, napkins, extracted tea powder, milk products, etc. Raw waste is shredded to reduce to its particle size to less than 12 mm. The primary aim of shredding is to produce a uniform feed and reduce plant “down-time” due to pipe blockages by large food particles. It also improves mechanical action and digestibility and enables easy removal of any plastic bags or cling-film from waste.

Fresh waste and re-circulated digestate (or digested food waste) are mixed in a mixing tank. The digestate is added to adjust the solids content of the incoming waste stream from 20 to 25 percent (in the incoming waste) to the desired solids content of the waste stream entering the digestion system (10 to 12 percent total solids). The homogenized waste stream is pumped into the feeding tank, from which the anaerobic digestion system is continuously fed. Feeding tank also acts as a pre-digester and subjected to heat at 55º to 60º C to eliminate pathogens and to facilitate the growth of thermophilic microbes for faster degradation of waste.

From the predigestor tank, the slurry enters the main digester where it undergoes anaerobic degradation by a consortium of Archaebacteria belonging to Methanococcus group. The anaerobic digester is a CSTR reactor having average retention time of 15 to 20 days. The digester is operated in the mesophilic temperature range (33º to 38°C), with heating carried out within the digester. Food waste is highly biodegradable and has much higher volatile solids destruction rate (86 to 90 percent) than biosolids or livestock manure. As per conservative estimates, each ton of food waste produces 150 to 200 m3 of biogas, depending on reactor design, process conditions, waste composition, etc.

Biogas contains significant amount of hydrogen sulfide (H2S) gas that needs to be stripped off due to its corrosive nature. The removal of H2S takes place in a biological desulphurization unit in which a limited quantity of air is added to biogas in the presence of specialized aerobic bacteria that oxidizes H2S into elemental sulfur. The biogas produced as a result of anaerobic digestion of waste is sent to a gas holder for temporary storage. Biogas is eventually used in a combined heat and power (CHP) unit for its conversion into thermal and electrical energy in a co­generation power station of suitable capacity. The exhaust gases from the CHP unit are used for meeting process heat requirements.

The digested substrate leaving the reactor is rich in nutrients like nitrogen, potassium and phosphorus which are beneficial for plants as well as soil. The digested slurry is dewatered in a series of screw presses to remove the moisture from slurry. Solar drying and additives are used to enhance the market value and handling characteristics of the fertilizer.

Diverting Food from Landfills

Food residuals are one of the single largest constituents of municipal solid waste stream. Diversion of food waste from landfills can provide significant contribution towards climate change mitigation, apart from generating revenues and creating employment opportunities. Rising energy prices and increasing environmental pollution makes it more important to harness renewable energy from food scraps and create a sustainable food supply chain.

Anaerobic digestion technology is widely available worldwide and successful projects are already in place in several European as well as Asian countries that makes it imperative on waste generators and environmental agencies to root for a sustainable food waste management system.

Recycling and Waste-to-Energy Prospects in Saudi Arabia

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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.

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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.

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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.

Conclusion

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.

Addressing India’s Waste Management Problems

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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.

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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.

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 waste management financing program, sorts of which are required to tackle issues like solid waste management.

Are Cities Hands-tied or is Change Possible?

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 electricity or 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.

Could Biomass Be The Answer To South Africa’s Energy Problem

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South Africa is experiencing a mammoth energy crisis with its debt-laden national power utility, Eskom, being unable to meet the electricity needs of the nation. After extensive periods of load shedding in 2018 and again earlier this year, it is becoming increasingly important to find an alternative source of energy. According to Marko Nokkala, senior sales manager at VTT Technical Research Centre of Finland, South Africa is in the perfect position to utilize biomass as an alternative source of energy.

Things to Consider

Should South Africa choose to delve deeper into biomass energy production, there are a few things that need to be considered. At present, a lot of biomass (such as fruit and vegetables) is utilized as food. It will, therefore, be necessary to identify alternative biomass sources that are not typically used as food, so that a food shortage is never created in the process.

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One alternative would be to use municipal solid waste from landfills and dumpsites as well as the wood waste from the very large and lucrative forestry industry in the country. It is also essential to keep in mind that an enormous amount of biomass will be needed to replace even a portion of the 90 million tons of coal that Eskom utilizes every year at its various power stations.

Potential Biomass Conversion Routes

There are a number of processing technologies that South Africans can utilize to turn their biomass into a sustainable energy source. Biochemical conversion involving technology such as anaerobic digestion and fermentation makes use of enzymes, microorganisms, and bacteria to breakdown the biomass into a variety of liquid or vaporous fuels.

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Fermentation is especially suitable when the biomass waste boasts a high sugar or water content, as is the case with a variety of agricultural wastes. By placing some focus on microbial fermentation process development, a system can effectively be created that will allow for large-scale biofuel production. Other technologies to consider include thermal methods like co-firing, pyrolysis, and gasification.

Future of biomass energy in South Africa

Despite the various obstacles that may slow down the introduction of large-scale biomass energy production in the country, it still promises to be a viable solution to the pressing energy concern. Biomass energy production does not require any of the major infrastructures that Eskom is currently relying on.

Although the initial setup will require a substantial amount of electricity, running a biomass conversion plant will cost significantly less than a coal-powered power plant in the long run. With the unemployment rate hovering around 27.1% in South Africa at present, any jobs created through the implementation of biomass energy conversion will be of great benefit to the nation.

Conclusion

Without speedy intervention, South Africa may very soon be left in the dark. Although there are already a number of wind farms in operation in the country, the addition of biomass conversion facilities will undoubtedly be of great benefit to Africa’s southernmost country.

Waste Management in Iraq

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Iraq is one of the most populous Arab countries with population exceeding 32 million. Rapid economic growth, high population growth, increasing individual income and sectarian conflicts have led to worsening problem of solid waste management problem in Iraq. Iraq generates around 31,000 tons of solid waste every day with per capita waste generation exceeding 1.4 kg per day. Baghdad alone produces more than 1.5 million tons of solid wastes each year.

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Rapid increase in waste generation is putting tremendous strain on Iraqi waste handling infrastructure which have heavily damaged after decades of conflict and mismanagement. In the absence of modern and efficient waste handling and waste disposal infrastructure most of the wastes are disposed in unregulated landfills across Iraq, with little or no concern for both human health and environment. Spontaneous fires, groundwater contamination, surface water pollution and large-scale greenhouse gas emissions have been the hallmarks of Iraqi landfills.

The National Solid Waste Management Plan (NSWMP) for Iraq was developed in 2007 by collaboration of international waste management specialist. The plan contains the recommendations for development and which explains the background for decisions.

The plan states that Iraq will build 33 engineered landfills with the capacity of 600 million m3 in all of the 18 governorates in Iraq by 2027. In addition to constructing landfills the plan also focuses on the collection and transportation, disposable, recycling and reuses systems. Environment education was also taken into consideration to ensure provision of educational system which supports the participation of both communities and individuals in waste management in Iraq.

Besides Iraqi national waste management plan, the Iraqi ministry of environment started in 2008 its own comprehensive development program which is part of the ministry of environment efforts to improve environmental situation in Iraq. Ministry of Municipalities and Public Work, in collaboration with international agencies like UN Habitat, USAID, UNICEF and EU, are developing and implementing solid waste management master plans in several Iraqi governorates including Kirkuk, Anbar, Basra, Dohuk, Erbil, Sulaimaniya and Thi Qar.

Recent Progress

Kirkuk was the first city in Iraq to benefit from solid waste management program when foreign forces initiated a solid waste management program for the city in 2005 to find an environmentally safe solution to the city’s garbage collection and disposal dilemma. As a result the first environmentally engineered and constructed landfill in Iraq was introduced in Kirkuk In February 2007. The 48-acre site is located 10 miles south of Kirkuk, with an expected lifespan of 10–12 years and meets both the U.S. Environmental Protection Agency and European Union Landfill Directive standards.

The Iraqi city of Basra also benefited from international aid with the completion of the first landfill that is compliant with international environmental standards has been completed. Basra solid waste management program developed by UNICEF will not only restore efficient waste collection systems in the city but will also create informal “recycling schools” that will help in spreading environmental awareness in in the city’s society by launching a campaign to educate the public about effective waste disposal practices.

In addition, Basra city program plans to establish a regional treatment and disposal facility and initiate street sweeping crews. Basrah city waste management program is part of the UNICEF program supported by the European Union to develop Iraq’s water and sanitation sector.

Erbil’s solid waste management master plan has also been developed by UNICEF with funding from the European Union. Recently a contract was signed by the Kurdistan Region’s Ministry of Municipalities and Tourism and a Canadian company to recycle the city’s garbage which will involve the construction of two recycling plants in the eastern and western outskirts of Erbil.

UNICEF has also developed a master plan to improve the management of solid waste in Dohuk Governorate which has been finalized in June 2011. Solid waste management master plans for Anbar, Sulaimaniya and Thi Qar governorates are also a part of UNICEF and EU efforts to attaining Iraq’s Millennium Development Goal targets of ensuring environmental sustainability by 2015.

Even though all of the effort by the international organizations are at local level and still not enough to solve solid waste management problem in Iraq, however these initiatives have been able to provide a much needed information regarding the size of the issue and valuable lessened learned used later by the Iraqi government to develop the Iraqi national waste management plan with the support of organizations such as UN Habitat, UNDG Iraq Trust Fund and USAID. The Iraqi national waste management plan is expected to ease the solid waste management problem in Iraq in the near future.

Recycling of EPS Foam Packaging

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Municipalities and organisations around the world are facing a growing problem in disposal and recycling of EPS foam packaging and products. EPS foam (Encapsulated Poly-Styrene) packaging is a highly popular plastic packaging material which finds wide application in packaging of food items, electronic goods, electrical appliances, furniture etc due to its excellent insulating and protective properties. EPS foam (also known as polystyrene) is also used to make useful products such as disposable cups, trays, cutlery, cartons, cases etc. However, being large and bulky, polystyrene take up significant space in rubbish bins which means that bins becomes full more quickly and therefore needs to be emptied more often.

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Polystyrene is lightweight compared to its volume so it occupies lots of precious landfill space and can be blown around and cause a nuisance in the surrounding areas. Although some companies have a recycling policy, most of the polystyrene still find its way into landfill sites around the world.

Environmental Hazards of EPS Foam

While it is estimated that EPS foam products accounts for less than 1% of the total weight of landfill materials, the fraction of landfill space it takes up is much higher considering that it is very lightweight.  Furthermore, it is essentially non-biodegradable, taking hundreds perhaps thousands of years to decompose.

Even when already disposed of in landfills, polystyrene can easily be carried by the wind and litter the streets or end up polluting water bodies. When EPS foam breaks apart, the small polystyrene components can be eaten by marine organisms which can cause choking or intestinal blockage.

Polystyrene can also be consumed by fishes once it breaks down in the ocean.  Marine animals higher up the food chain could eat the fishes that have consumed EPS, thus concentrating the contaminant.  It could be a potential health hazard for us humans who are on top of the food chain considering that styrene, the plastic monomer used in manufacturing EPS has been classified by the US National Institutes of Health (NIH) and the International Agency for Research on Cancer (IARC) as a possible human carcinogen.

Styrene is derived from either petroleum or natural gas, both of which are non-renewable and are rapidly being depleted, creating environmental sustainability problems for EPS.

Trends in EPS Foam Recycling

Although the Alliance of Foam Packaging Recyclers have reported that the recycling rate for post-consumer and post-commercial EPS in the United States have risen to 28% in 2010 from around 20% in 2008, this value is still lower than most solid wastes.  According to USEPA, auto batteries, steel cans and glass containers have recycle rates of 96.2%, 70.6% and 34.2% respectively.

Because it is bulky, EPS foam takes up storage space and costs more to transport and yet yields only a small amount of polystyrene for re-use or remolding (infact, polystyrene accounts for only 2% of the volume of uncompacted EPS foams). This provides little incentive for recyclers to consider EPS recycling.

Products that have been used to hold or store food should be thoroughly cleaned for hygienic reasons, thus compounding the costs.  For the same reasons, these products cannot be recycled to produce the same food containers but rather are used for non-food plastic products.  The manufacture of food containers, therefore, always requires new polystyrene.  At present, it is more economical to produce new EPS foam products than to recycle it, and manufacturers would rather have the higher quality of fresh polystyrene over the recycled one.

The cost of transporting bulky polystyrene waste discourages recyclers from recycling it.  Organizations that receive a large amount of EPS foam (especially in packaging) can invest in a compactor that will reduce the volume of the products. Recyclers will pay more for the compacted product so the investment can be recovered relatively easier.

There are also breakthroughs in studies concerning EPS recycling although most of these are still in the research or pilot stage.  Several studies have found that the bacteria Pseudomonas putida is able to convert polystyrene to a more biodegradable plastic.  The process of polystyrene depolymerization – converting polystyrene back to its styrene monomer – is also gaining ground.

Municipal Solid Waste Management in Oman

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Municipal solid waste management is a challenging issue for the Sultanate of Oman. With population of almost 3 million inhabitants, the country produces about 1.9 million tons of solid waste each year. The per capita waste generation in Oman is more than 1.5 kg per day, among the highest worldwide.

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Prevalent Scenario

Solid waste in Oman is characterized by very high percentage of recyclables, primarily paper (26%), plastics (12%), metals (11%) and glass (5%). However the country is yet to realize the recycling potential of its municipal waste stream.

The predominant waste disposal method in Oman is landfilling. Most of the solid waste is sent to authorized and unauthorized dumpsites for disposal which is creating environment and health issues. There are several dumpsites which are located in the midst of residential areas or close to catchment areas of private and public drinking water bodies.

Solid waste management scenario in Oman is marked by lack of collection and disposal facilities, as well as lack of public awareness about waste in the country. Solid waste, industrial waste, e-wastes etc are deposited in very large number of landfills scattered across the country. Oman has around 350 landfills/dumpsites which are managed by municipalities. In addition, there are numerous unauthorized dumpsites in Oman where all sorts of wastes are recklessly dumped.

Al Amerat Sanitary Landfill

Al Amerat landfill is the first engineered sanitary landfill in Oman which began its operations in early 2011. The landfill site, spread over an area of 9.6 hectares, consists of 5 cells with a total capacity of 10 million m3 of solid waste and spread over an area of over 9.6 hectares. Each cell has 16 shafts to take care of leachate (contaminated wastewater).

All the shafts are interconnected, and will help in moving leachate to the leachate pump. The project is part of the government’s initiatives to tackle solid waste in a scientific and environment-friendly manner. Being the first of its kind, Al Amerat sanitary landfill is expected to be an example for the future solid waste management projects in the country.

The Way Forward

Solid waste management is among the top priorities of Oman government which has chalked out a robust strategy to resolve waste management problem in the Sultanate. The country is striving to establish 16 engineered landfills, 65 waste transfer stations and 4 waste treatment plants in different parts of the country.

Modern solid waste management facilities are under planning in several wilayat, especially Muscat and Salalah. The new landfills will eventually pave the way for closure of authorized and unauthorized garbage dumps around the country. However investments totaling Omani Rial 2.5 billion are required to put this waste management strategy into place. Oman is also seriously exploring waste-to-energy as a tool to manage garbage in a sustainable manner.