Wastes of a solid nature needs to be discharged and disposed such that it will not harm the environment or people’s health. The Omani government therefore constructs landfills to avoid disease separation, insects accumulation and groundwater contamination. The aim of the landfill is for the disposal of waste which is not combusted for energy recovery, reused or recycled. The construction of the landfill and its operation is carried out based on the regulations of Omani to reduce solid waste effect on the environment.
A visit to the site of the Al Amerat Sanitary Landfill in the area of Al Mutaqaa was carried out on April 1. The site visit was intended to know and gather data on the operation and construction of the landfill as well as gain knowledge on the process of waste separation and collection.
Information on geography and history
The first Omani landfill, which is located in Al Mutaqaa Area, is the Al Amerat Sanitary Landfill. The operation of the sanitary landfill is the responsibility of the Sita and Al Basheer Environment LCC. The operation of the landfill began on February 2011 with the site area covering more than 9.6 hectares, solid waste capacity of 1 million m3 and 5 cells. Every cell have 16 shafts that control the leachate. Leachate pump are linked to this shaft so as to aid movement in the leachate. This is one of the initiatives of government in solid waste management in municipals to create a friendly environment.
Specifications for details and designs of engineering
For land authority assurance:
- Regularly monitored groundwater boreholes
- Control of Third party construction activities
- Initial geological and survey by the hydrogeological environmental.
Several properly designed engineering design were implemented in the landfill. For the land fill in Al Amart, the modified high rise technique was adopted. There were also many methods of modification that were applied so as to minimize the formation of leachate as well as cost reduction and needs for material cove as well as the site life time increment.
The initial process for the high rise technique is waste gathering followed by waste layer compaction on the surface of the floor. After the covering of every layer, a pyramid is formed by placing layers over each other. Due to the slope, there are less waste in the upper layer. The advantage of this technique is that a restricted area of land is needed leading to a reduction in pollution. Furthermore, the technique is applied in coastal areas and areas with high water table.
Specifications of the Al Amarat Area
- Systems of ventilations which has well and channels control the site of the released gas.
- Network is used to monitor the groundwater.
- Fluid is drained from the site through a drainage system.
- The site layers do not allow water to pass through.
- The waste is covered with inorganic soil.
- The flood plains and valleys are not close to the site.
- To avoid car accidents as a result of gathering of birds, the site is not located close to air traffic lines.
- The site is also not located close to residential and sensitive areas.
Diagram of the skeletal flow of the facility
Figure 1: Diagram of facility flow “presentation of site visit”
Waste composition and sources
Table 1: Waste composition and sources
|Institutional||Government centers, prisons, hospitals, schools||Hazardous wastes, special wastes, metals, glass, food wastes, wood, plastics, cardboard, paper|
|Commercial||Office buildings, markets, restaurants, hotels, stores, etc||Hazardous wastes, special wastes, metals, glass, food wastes, wood, plastics, cardboard, paper|
|Residential||Multifamily and single dwellings||Household hazardous wastes, special wastes (such as tires, oil, batteries, white goods, consumer electronics bulky items), ashes, metals, glass, wood, yard wastes, leather, textiles, plastics, cardboard, paper, food wastes|
|Industry waste||Power plant
|Metals, plastics, rubber, food, etc.|
|Construction and demolition waste||Demolition site||Construction materials such as metals, masonry, bricks and pipes amongst others|
|Composite waste||Stores or market
|Fabrics and plastics|
|Ash waste||Stores or markets
|Remains of fine (cooking and heating)
|Rubbish waste||Stores or markets
|Food serving and preparation
|Food waste||Power plant
Waste from food processing
Systems for collection of Waste
Collection and separation of wastes need to be managed, from where they are produced, so that recyclable and reusable materials can be discovered.
At Al Amerat landfill, the initial process is waste collection where waste of about 900 thousand tons is delivered at the landfill. The waste is compacted to a 30 m height in the first cell.
The landfill uses the Hauled container system (HCS). The container is subsequently transported to the site of disposal, where it offloads the waste and returns to its initial position.
Maintenance and operation
The various composition of waste are gathered in the landfill including food waste, bottles, plastic, papers, etc. This is the process of operating the landfill:
- The solid waste from the municipal is not combined with the hazardous waste.
- The amount of waste gotten is weighed in the truck with the aid of the weighing scale.
- For the sake of hygiene, the tires of the trucks are cleaned by machine.
- Rain water is prevented from getting into the waste by using a plastic sheet to cover the final layer. The plastic sheet also gives a neat look.
- To avoid bad smell, rainwater is stopped from getting into the waste by using plastic cover or soil to cover each of the waste’s layer.
- 2 compactors are used to compress the waste. Every layer is compressed at least 3 times to 20 cm.
- For secondary waste regulation, the contents of the truck are removed.
- For primary control of waste, 140 trucks, carrying waste gets to the landfill and their contents are weighed.
Figure 3: Area of landfill (Anon, 2010)
Control and generation of gas and Leachate
Gas and leachate are environment hazards which cannot be seen with the eyes. Leachate can lead to ground water contamination, as it is a liquid that forms the disposed layers of waste. Methane and other landfill gas is created by waste decomposition. Explosions and fire can be started in close structures as a result of methane, which is a combustible gas. Leachate on the other hand can lead to death of fish, drinking water contamination and poisoning of lakes. Gas and leachates thus requires monitoring to prevent pollution of the environment.
Monitoring of environment
There exist many systems for monitoring and regulating the locations where solid wastes are dumped as well as leachate, landfill gas and groundwater in Al Amerat.
Monitoring of groundwater: The available holes are used to monitor the groundwater’s water quality. Bi-annually, the water is checked through a sample, which is tested to check how safe the water is.
Monitoring of landfill gas (LFG): The system for extracting LFG from wells of gas is present to test the gas in the landfill. The system for extraction is optimized for the best results.
Monitoring of leachate: a leachate sample is carried to leachate plant treatments to test its results.
Extant issues and enhancing solutions
Many issues exist that were created when the landfill was being designed and operated. Solutions are being implemented to minimize the problems’ effect on health and environment.
- Groundwater can be contaminated with leachate, which is a form of liquid that moves through layers of wastes in the landfill.
- Regularly testing samples of leachates in the treatment plants.
- Leachate transfer into the groundwater is prevented by placing at the landfill’s bottom layer, a landfill liner.
- Combustible methane gas is produced by organic waste.
- Landfill constructed with high rise technique.
- Compression and excavation of soil leads to the production of soil. This creates medical issues including asthma and infection.
- Dust spread is prevented with the aid of plastic sheets used to cover the solid wastes.
- Workers are given face masks.
- Materials combustion can result to fire, which would be hazardous in the landfill.
- The landfill does not accept materials that are inflammable.
- Build-up of gas is allowed
- Opens between 6:00am and 6:00pm
- Actual quantity of more than 800 Tons daily (7 days of the week)
- Expected 250,000 tons every year
- Lifetime expectation of 4 years
- Started operation in February 2011
- Volume of 1,000,000 m3
- Constructed in 2005.
- 2 buses
- 2 pick up
- 1 tanker 20m3 (Renault Premium)
- 2 hook lift (Renault Premium)
- 1 Excavator
- 1 track loader
- 1 Bulldozer
- 2 Compactors
The landfill in Al Amerat is Omani’s first landfill that aids in the reduction of health hazard and pollution in the environment. The landfill features a great designed and is a good proof of the efforts of the government of Omani in reducing solid waste. Furthermore, Oman’s solid waste management can be enhanced by more people education and awareness. Lastly, the visit to the site was enlightening and it was in line with the module’s objective.