SINGAPORE — When Mr Eng Tiang Sing was tasked to play a key role in building Singapore’s first offshore landfill in 1995, he wondered how he would transfer tonnes of incinerated ash across the sea.

At that time, Mr Eng was a deputy chief engineer with the Ministry of the Environment — now known as the Ministry of the Environment and Water Resources (MEWR) — and he had to oversee the construction of Semakau Landfill.

Plans to develop Pulau Semakau, an island located 8km south of the Singapore mainland, were first mooted in 1989 when the Government recognised that the dumping grounds located on the mainland would be full to capacity by the 1990s.

Back then, ash from incinerated waste was disposed at two landfills located in Lim Chu Kang and Lorong Halus.

When no suitable landfill sites could be found on the main island, the Government decided to create a landfill by enclosing the waters between the eastern part of Pulau Semakau and the western part of Pulau Sakeng.

In doing so, two islands were merged to form the new landfill which spans 350ha, or the size of 490 football fields.

Mr Eng Tiang Sing (left) with Mr Koh Hee Song, the former head of the engineering services department at MEWR, at Semakau's 20th birthday event. Photo: Nuria Ling/TODAY

Mr Eng, who is now aged 65, told reporters on Tuesday (Dec 10) that his team could not turn to other countries for inspiration because no one else had an offshore landfill.

Speaking at an event to mark the 20th anniversary of Semakau Landfill, he said: “Many landfills that we saw in places like New York, in the United States, or Japan had landfills in the foreshore, meaning they are just off the coast.”

This meant that waste could be transferred over land to the landfills, Mr Eng explained.

However, setting up a landfill 8km from the mainland meant that the only way waste could be transported over the sea was by a barge.

The team eventually decided to build a transfer station in Tuas to act as a collection point for waste. Ash from waste-to-energy plants in Singapore as well as waste that could not be incinerated would be loaded onto a barge that could hold up to 3,000 tonnes of waste.

The barge would then travel 30km across the sea to Semakau.

This is how Singapore’s rubbish has been transferred to the landfill for the last 20 years.

During the commemorative event, which was held on the landfill, Dr Amy Khor, who is Senior Minister of State for the Environment and Water Resources, cut a cake in the shape of Semakau before taking a tour around the landfill with other guests.

SEMAKAU FILLING UP FASTER THAN EXPECTED

Mr Eng, who was one of the guests at the event, told reporters that when the landfill was first constructed, it was expected to last until 2045.

“We always use the term ‘hoping to’ and ‘up to’ 2045, but you have to keep on adjusting (the timeline) because waste increases. With people throwing away more, your (landfill’s) capacity is also reduced,” Mr Eng said.

In 2013, the National Environment Agency (NEA) reduced Semakau Landfill’s estimated lifespan to 2035 after taking into account economic and population growth.

Mr Eng, who is now retired, said that in light of the revised timeline, he hopes that the plans by MEWR to reduce waste will work, so that the landfill’s lifespan will be extended back to 2045 and even beyond.

In August 2019, MEWR set targets to reduce the amount of waste sent to Semakau each day by 30 per cent by the year 2030.

Semakau, which can hold up to 28 million cubic metres of waste, now receives 2,100 tonnes of waste daily.

To reach the 2030 target, the Resource Sustainability Act was passed in September this year to regulate three waste streams, namely e-waste, food waste and packaging waste.

Under the Act, companies that manufacture or import products for sale here must be responsible for the collection and proper treatment of their e-waste. Malls and large hotels must segregate their food waste for treatment.

REDUCING ACCIDENT RISK

Among the other challenges that Mr Eng and his team faced when constructing the landfill in the 1990s was to reduce the risk of accidents by the barge when it was travelling across busy sea lanes.

He said that the team built a larger barge so that more ash could be transferred to Semakau in a single trip, rather than over multiple trips which could increase the risk of accidents when crossing sea lanes.

Mr Eng’s team also had to preserve the biodiversity of the island. While the team could not avoid removing about 13.6ha of mangrove plants during the construction phase, it eventually bought 400,000 mangroves from Indonesia and replanted them in the exact same area when construction of the landfill was completed.

His team also had to resettle 200 villagers who lived on the island at that time and relocate graves on the island to the mainland.

When asked how he would feel when the landfill eventually runs out of space, Mr Eng was positive, saying that the landfill will become a piece of land that can be used for other purposes.

However, he said that it will be up to the future government to decide what the land will be used for after it is filled to its maximum capacity.