Semakau Landfill - Waste Disposal in Singapore, Nov. 2004

Semakau Landfill - Waste Disposal in Singapore

November 3, 2004

How does Singapore manage its waste disposal? Well, at a cost of S$610 million, an offshore landfill covering an area of 350 hectares was built. Commissioned in 1999, its expected to last 30 years. Augustine Anthuvan visited this landfill site recently to get an update on Singapore's solid waste management system.

The sustainability of any country, especially for a small island-state like Singapore, begins with ensuring that physical land resources are not overwhelmed by the waste people generate.

Southern side of the landfill with an opening that facilitates flow of fresh water into the cell.

At the moment, Singapore recycles about 44 percent of its waste. Most of the materials recovered come from the industrial and commercial sectors. The remaining waste is sent either for incineration at one of the four incineration plants, or to the landfill site. But even before the Lorong Halus Landfill site on the mainland was decommissioned in April 1999, the Singapore government had already begun its search for alternatives.

Because of the limited land - the main island of Singapore being only 682 square kilometers - the authorities began to look offshore - and so finally the decision was made to build a landfill site enclosing a part of the sea off the islands of Semakau and Sakeng. In May 1995, the Ministry of the Environment started work on a seven-kilometre-long perimeter bund and wharf at Pulau Semakau. It was commissioned in April 1999.

The Semakau Landfill is Singapore's only landfill for waste disposal. It covers a total area of 350 hectares and has a landfill capacity of 63 millions cubic metres This landfill is expected to meet Singapore's need for landfill space beyond the year 2030. The supporting infrastructure for this offshore landfill includes a refuse transfer station at Tuas located on the western side of the island. Refuse is transferred into barges at this station and transported to Pulau Semakau. A large supporting fleet of overland transporters, barges, dumpers and bulldozers are also required.

When developing the landfill, care was taken to protect the marine ecosystem to ensure that the mangrove swamps and corals were left untouched. And the role of the 7 km confinement bund is to prevent any pollution of the sea surrounding the landfill site.

For a first hand view, Augustine Anthuvan visited Semakau and met up with Mr Vincent Teo, General Manager of Semakau Landfill which is managed by the National Environment Agency. Mr Teo, what is the current state of waste disposal in Singapore? “We have currently an average of about 6,900 tonnes of waste generated a day in Singapore. This waste comes mainly from domestic households, trade and commercial premises and also some non-hazardous waste from industries. Of this amount, about 92% are incinerable wastes and they are disposed of at the four incineration plants. The remaining 8% are non-incinerable wastes such as construction and demolition wastes and they are disposed of at the off-shore sanitary landfill on Pulau Semakau. Incineration reduces the volume of waste by about 90%. And the incineration ash from the incineration plants is also disposed of at Semakau Landfill”.

Why can't we rely on incineration alone, Singapore has some very high-tech incineration plants on the mainland, so why the need for landfills?

“You see incineration reduces the volume by 90%. At the end of the incineration process, we still have that 10% of waste (incineration ash) to be landfilled in Semakau landfill. Now over and above these we have what we call the non-incinerable wastes (waste that cannot be incinerated) that still have to be landfilled. So we still need a landfill no matter which option we choose”. Could you describe the rationale behind going for an offshore landfill versus finding a site on the mainland?

“The last landfill was located at Lorong Halus on the main island of Singapore. This was depleted in 1999. The landfill was closed. As there were no other suitable sites left for landfill on the main island, an offshore landfill had to be constructed as a last resort”.

Tell us a little bit about the design and envrironmental safeguards that have been built into this Pulau Semakau landfill? “The Semakau landfill covers a total area of about 350 hectares. This created a landfill capacity of about 63milion cubic metres. Now to create this landfill space, a seven-kilometer perimeter rock bund was built to enclose a part of the sea off Pulau Semakau and the former Pulau Sakeng. Now this perimeter bund is lined with an impermeable membrane as well as a layer of marine clay to ensure that leachate, which is wastewater generated in the landfill itself, is contained within the landfill area. The perimeter bund prevents leaching of wastewater into the surrounding seas. Monitoring wells are also installed all round the perimeter bund and regular water sampling is conducted to ensure that there is no leak through the liners. And this leachate is led to a leachate landfill treatment plant, which is specially constructed for this purpose. And the treated effluent is finally discharged into the sea. Now the quality of the treated affluent complies with watercourse standards”. Before we wrap up, perhaps you could walk us through how all the waste is transported from the mainland to this landfill site, which is quite a distance from the main island right?

“Semakau landfill consists basically of two locations. We have the Tuas Marine Transfer station (TMTS) which is located on western side of the main island of Singapore. Its basically to consolidate the waste, such as the non incinerable waste as well as the incineration ash. This waste is consolidated onto barges. These barges at the end of the day are closed and are then pushed to Semakau landfill which is about 25 kilometres away, a three hour journey and the waste is brought here to Semakau landfill for final disposal. Now upon arrival, the barges are actually berthed in an enclosed transfer building and excavators with special custom-built grabs are used to off load the waste onto dump trucks. And the dump trucks finally are driven to the active landfill site for final dumping of the waste”.

The Semakau landfill site was built at a cost of S$610 million and contrary to popular belief that the site might be dirty and smelly, Semakau proved to be quite scenic when I visited the site, offering an unparalleled view of the seas and islands around Singapore.

In fact over the years, several groups have organized visits to the site for both adults and children and it has become now a must see site on any environmental or eco trip. When you visit the Semakau landfill site, you’ll notice it has been divided into eleven cells with plans even for phase two.

But even with this and four incineration plants built on the main island of Singapore, at a current average of 6900 tonnes of waste being generated a day in Singapore - if we allow this current growing trend of refuse to continue, Singapore would need to build a new incineration plant every five years at a cost of a few hundred million dollars and provide a landfill the size of Sentosa island at a cost of 600 million dollars every 30 years. And this may not be sustainable in land scarce Singapore.

Which is why the challenge of waste disposal is not unique to Singapore alone, as countries around the world have expressed similar concerns as well. But in order to address this and turn things around, there must be determination on the part of every Singaporean and every person living here in Singapore, to cut down the amount of waste going into incineration and landfill sites. This strategy of minimizing waste and maximizing recycling is even more pertinent in the context of Singapore.