Dompe landfill site gets off the ground
The recent commissioning of a fully-fledged sanitary landfill in Dompe, with a capacity of 165,000 cubic metres of waste, marked a landmark development in Sri Lanka’s country’s solid waste management.
Spread across a land extent of two hectares within a commercial forest in Maligawatte, Dompe , this Rs. 450 million garbage disposal project funded by a South Korean Government grant is an integrated Waste Management system put in place exclusively for the disposal of the municipal solid waste collected from Dompe area. The grant included feasibility study, consultancy, construction of the maintenance building and landfill with its supporting services, construction of the treatment plant, training and capacity building, provision of landfill vehicles and heavy equipment. The Sri Lanka government too allocated counterpoint funding of Rs. 150 million for infrastructure such as the preparation of the earthen pit etc.
What you see from outside: The basin shaped enclosure divided into cells
The Korean International Development Agency (KOICA), Seoul’s Official Development Assistance (ODA) body has pledged to continue its support during the operational and maintenance period also to ensure its sustainability.
The Dompe sanitary landfill model project of the Central Environmental Authority of the then Ministry of Environment and Natural Resources was initiated back in 2009, but came to an abrupt halt when it was met with much resistance by the area’s residents who feared that garbage brought from elsewhere would be dumped at the location as much as they feared it would cause soil and water contamination. Having allayed the concerns of the residents through awareness about the special features of this well-integrated sanitary landfill, environmental officials have now been able to successfully implement the project.
“People think landfill is a place to dump all the mixed waste. But it is not so,” says Deputy Director General of the Environment Education and Awareness Division Jayavilal Fernando.
Distinguishing between different types of waste, the DDG says, in a heap of waste there are certain waste you can recycle such as plastic, polythene, paper and metal while there is another component of waste which is biodegradable, such as food waste, kitchen waste etc. Components like ceramics, pampers, do not have a final solution except disposal in a sanitary landfill like the one in Dompe, he said.
Additionally you find some small quantities of biodegradable items which takes a considerably longer time to decompose and require certain environmentally friendly disposal methods.
“Therefore landfill will have non-biodegradable components which cannot be recycled or reused and sometimes biodegradable components which take a longer time to get decomposed,” he says.
Highlighting the benefits of a sanitary landfill Mr. Jayavilal says that in a non- sanitary landfill, water that gets collected from the waste can contaminate the ground /surface water, as much as it would lead to various environmental issues such as soil pollution, vector breeding, destruction to eco-system etc. Burning the waste in a normal environment is equally harmful according to him, as it emits toxic gases.
“In a sanitary landfill system, we have taken measures to avert all these environmental issues,” he says adding that of the solutions for disposal of waste, landfill is the most feasible solution for a country like Sri Lanka.
During a visit to the site, the Sunday Times was able to witness the precautionary methods adopted in designing the landfill. The landfill had been excavated to take the shape of a basin and what you witness from outside is only a black surface, partitioned into cells, However, below are number of linear systems that have been established to prevent soil and water contamination.
Once the basin type structure was created by excavating the soil, Korean experts put in place a comprehensive liner system to prevent possible soil, water contamination. Accordingly, the side bunds of the landfill had been covered with two layers of Geotextile, a special Bentonite clay layer and High-density Polyethylene (HDPE) layer of 1.5 mm thickness so as to prevent waste water from sweeping through the side bunds.
The bottom has been constructed with four layers consisting of a metal rock layer, Geotextile layer, clay mixed Bentonite to a thickness of one foot and a HDPE liner. It also has a drainage pipe network at the bottom as a counter measure to tackle the rising of the ground water level.
There are gas venting systems to provide oxygen into garbage so that the formation of Methane during the early stages of the landfill can be prevented.
The Dompe landfill is also equipped with several other vital units – a vehicle washing plant at the entrance to clean the lorries that leave the site after unloading the waste, a composing plant where the garbage brought to the site is segregated and recycled, a water treatment plant to purify the waste water, known as Leachate collected from the landfill, and an artificial wetland where the treated water is directed for further purifying before being released to the natural environment.
In addition, there are three monitoring wells placed in three different locations close to the landfill for constant scrutiny of the quality of the ground water around the landfill so as to detect any possible water contamination. The maintenance building put up at the site will be converted into a training centre in future to facilitate training in relation to waste management for students, officials of the CEA and other local bodies, it is learnt.
With the pilot project of the Dompe sanitary landfill having now got off the ground, authorities are exploring the possibility of duplicating the model in other areas as well, the DDG said.