Methane gas detected at Ta' Zwejra

The presence of good quality methane gas was yesterday detected for the first time at the engineered landfill at Ta' Zwejra.

Tests for the presence of the gas were made in the presence of Prime Minister Lawrence Gonzi during a visit to the engineered landfill.

The first engineered landfill at Ta' Zwejra was built in such a way as to enable it to produce gas. This was a learning experience for WasteServ and although any landfill does not produce large quantities of gas in its initial years, yesterday's results made WasteServ staff present visibly excited, as these confirmed that they had done the right thing.

The engineered landfill has five layers at the bottom, which include a synthetic clay layer and a membrane to prevent leeching from the municipal waste while when the waste reaches the planned levels, this is covered by soil, a synthetic clay layer, rubber from shredded tyres and soil. Turf will then be grown on the upper level, but a network of pipes within the landfill would tap the methane gas that builds up in the landfill.

The gas that is being produced at the moment will eventually have to be removed and flared because otherwise pressure builds up. But the landfill will produce more gas after a period of about four years and since there will be other engineered landfills in the area, the gas from them and from the old Maghtab landfill could be tapped and if the quantities are sufficient, a decision would be taken whether to invest in a generator to be used on site or to feed the produced power into the national grid.

The contrast could not have been more striking yesterday: with smoke leaking from the smouldering pockets of the old Maghtab landfill on the one hand and the capping of the first new engineered land fill on the other.

Some 900 tonnes of domestic refuse are being dumped daily at the second landfill at Ta' Zwejra and a considerable amount of land would have to be gobbled up for another landfill that would last for about 30 years.

The Prime Minister stressed the importance of looking at new technologies to treat waste to prevent such loss of land, and Environment Minister George Pullicino said the committees that the government had entrusted with formulating reports on the waste strategy and on the possibility of having waste to energy facilities would soon finalise their reports.