Muscat – be’ah announced that it has successfully completed the closing process of Cell 1 of Barka Landfill, South Batinah. This process is the second of its kind in the region and aims at controlling and extracting biogas emissions to prevent future pollution and minimise risks to the environment and human health.
‘The goal of closing the landfill cell is to reduce the amount of leachate produced from bioprocesses, control the odour, and begin the safe disposal of biogas by burning or redirecting it to industrial use,’ be’ah stated.
As standard practice, be’ah initiates final closing and decommissioning procedures of all landfills that reach their capacity in line with the best international environmental practices in the industry. Before closing, be’ah had stopped receiving municipal waste and discontinued operations in engineering Cell 1. Closing operations have been undertaken with the utmost care to ensure the long-term protection of the surrounding environment by using insulating geosynthetic lining materials that prevent rainwater and oxygen from leaking into the cell, and these layers were also covered with a proper layer of soil and riprap for added protection.
In order to reduce the environmental impact of biogas emitted from landfills and their risks to human health, biogas emitted after closure as a result of the vital processes in the engineering cell are removed through an efficient extraction system. Chief among these gases is methane (CH4), one of the main greenhouse gases and a key driver of global warming with a far superior potency compared to carbon dioxide (CO2). Biogas is passed through a gas flaring unit designed to burn and dispose of gas emissions in accordance with the highest quality standards.
The extraction and collection of biogas is crucial after closing any engineered landfill cell in order to prevent gas accumulation and pressure build-up inside the cell. Specially designed wells are built and used to extract and transfer the gas through a network of pipelines delivering it to a 2000m3/hour flaring unit (burning station). There, the energy recovery journey begins where, most commonly, biogas is used to generate electricity.
The design of the final cover of the closed cell is implemented in compliance with the requirements and design standards of the United States Environmental Protection Agency. Additionally, the site and the surrounding area will be subject to 30 years of continuous environmental monitoring, including groundwater and leachate monitoring.
The post-closure phase includes long-term maintenance of closed landfills and cells to reduce their impact on the surrounding ecosystem. During this phase, the stability of cover materials is ensured and all gaps that may compromise proper sealing are filled to prevent stagnant water. Prior planning is usually carried out, as early as the initial landfill design phase, to identify possible uses for the landfill after its closure, bearing in mind that the future use of decommissioned landfills is also affected by geography as well as their topography and shape. Future uses of landfills may include transforming them into recreational parks, golf courses or other sports playgrounds.