Study: Underground landfill possible

Such a facility is technically feasible, but costs have to be worked out
Feng Zengkun Straits Times 12 Nov 12;

SINGAPORE could have an underground landfill to contain about 40 years' worth of rubbish, a feasibility study has found.

The facility would be in western Singapore and take up about 8 sq km, slightly more than one-hundredth of the country's land size.

The findings of the government-initiated study were presented last week during the 13th World Conference of the Associated Research Centres for Urban Underground Space, which ended last Friday. Singapore hosted the event for the first time.

Urban Redevelopment Authority group director Richard Hoo said: "We are still at the design and study stages. We have to make sure the cost equation works out."

Currently, organic waste here is incinerated. The ashes and non-incinerable waste are deposited on Pulau Semakau, an offshore landfill in use since 1999.

Work on the Semakau landfill, which is expected to have a completed capacity of 63 million cubic m, is ongoing.

The study on the underground landfill was part of a wide-ranging look at 10 possible uses of below-ground space here. Other ideas were for power stations, warehouses and reservoirs.

Initiated by the Government in 2008, the study was carried out by Singapore-Norwegian consortium Sintef-Tritech-Multiconsult and completed a year later.

According to the study, the underground landfill could consist of 840 silos, each 60m deep and with a diameter of 40m, laid out in a grid about 60m underground.

It would have a capacity equivalent to the Semakau facility's.

The authors of the study said the design of the underground landfill has some flexibility because it consists of multiple silos. Fewer or more can be excavated depending on efforts to reduce waste, for example, via recycling.

Senior Minister of State for Trade and Industry and National Development Lee Yi Shyan said during the conference that Singapore faces challenges in developing underground space.

"Our terrain is mostly flat, with good rocks located deep beneath the surface. These mean greater capital and operational costs for underground development," he noted.

The Republic can look to other cities such as Toronto and Tianjin, which have more experience in the field, he added.

The Ministry of National Development has called for research proposals to create new space and highly liveable, compact model towns for Singapore's long-term growth. The deadline is Wednesday.