The Magħtab landfill will be transformed into a green hill, embellished with more than 20,000 trees, after the planning authority yesterday approved the rehabilitation of the site.

The process of turning the dump into a park will likely take years as the place first needs to be rendered safe and then a separate permit applied for, but the idea is for it to eventually become a recreational area.

In fact, despite tons of gas having already been extracted from the waste buried underneath the landfill, there are still two gas hot spots where there is a chance of fires igniting, case officer Johann Buttigieg said.

So, as part of the permit process to have the place opened as a recreation area, the area would have to be tested for emissions and safety beforehand, he said.

The works, to be carried out by WasteServe, are expected to be completed by 2013.

Works on the site, which covers over 630,000 square metres, will include the landscaping of 200,000 square metres of the sloped land.

A variety of trees will be planted such as olive trees, oaks, pines, honeysuckles and pomegranate trees.

The landfill will be capped with a material layered beneath the soil level, which will separate the waste buried in the landfill from its surrounding environment. This will reduce the infiltration of pollutants into fresh water and minimise the escape of toxic gas emissions.

The gas emissions are also being controlled through a system that was approved by Mepa six years ago. This involved the installation of 400 steel wells and 80 kilometres of pipes through which gas emissions were extracted. About 6,000 cubic metres of gas were extracted every hour.

Through the capping, rain water will no longer be allowed to infiltrate through the mound, so the plans allow for the installation of storm water culverts and reservoirs to collect water for irrigation and fire control.

A four-tier silt pond, built close to the coast road, would ensure that debris that falls down the slope settles there instead of falling into the highway or the sea.

Water will also be purified naturally as it seeps from one tier to the other.

According to the plans, the existing access to the landfill will be substituted by a new road leading directly onto Magħtab. This new link will also be used for the operation of the Għallis engineered landfill.