www.nea.gov.sg
  CLEANER & GREENER
 

Waste Not, Want Not

Imagine standing in the middle of a soccer field full of boxes stacked to an average man’s height. Now imagine this field surrounded by 300 similarly filled soccer fields. NOW replace all the boxes with rubbish. That’s 2.56 million tonnes of refuse, the amount Singaporeans sent to their four waste-to-energy plants (for incineration) and landfill (for non-incinerable refuse) in 2006! Amazingly, this is after an almost equivalent amount of refuse had been sent for recycling!

Last year, a total of 2.56 million tonnes of waste was disposed of at the refuse disposal facilities. Approximately 2.33 million tonnes or 90.8% was incinerated while the remainder went to the Semakau Landfill.

The provision of waste collection and disposal services in Singapore is so seamless that many are not aware of the vast investment in a process that transforms huge volumes of rubbish into inert ash. Most of the time, we take this for granted.

Today, NEA operates four waste-to-energy plants (WTEPs) with a combined incineration capacity of 8,200 tonnes per day and the Semakau Landfill. These disposal facilities are ISO 9001 and ISO 14001 certified, testifying to their high standards.

Without these WTEPs, a landfill the size of 300 soccer fields would need to be set aside every year for our waste! With incineration, supported by other waste minimisation and recycling measures, we can extend the life of our only landfill beyond 2040.
Watt’s Up With Waste
Work on Singapore’s fifth waste-to-energy plant, which is capable of producing 20MW of green electricity from solid waste, is progressing smoothly. Following the groundbreaking ceremony in October 2006, piling work for this design-buildown- operate project by Keppel Seghers was completed in mid-April 2007.

While the main focus of incineration is volume reduction, each plant is also equipped with energy recovery features, hence the term ‘waste-to-energy plants’. Two to three per cent of Singapore’s electricity needs, or 954,237MWh, was generated from waste in 2006.

This means a corresponding reduction in the amount of electricity that would otherwise have to be generated using fossil fuel at the power stations, reducing the resultant emissions.

Our Semakau Landfill continues to be a magnet for both local and foreign visitors. In 2006, it hosted 953 visitors from four interest groups who enjoyed activities ranging from inter-tidal walks to bird watching to sport fishing and even stargazing!

In addition, close to 6,000 foreign and local visitors were there to learn more about waste management in Singapore.
Injecting Green Innovation
NEA has harnessed innovation in a bid to operate its assets more efficiently and cleanly. Two notable green innovations that have taken place at the WTEPs are the completion of the new flue gas treatment plant at the Tuas plant and the use of the Six Sigma methodology to reduce electricity consumption at the Senoko plant.

The construction of the additional flue gas treatment plant at Tuas was completed at a cost of $32 million. It also features a series of state-of-the-art honeycombed catalyst elements that break down gaseous dioxins in the flue gas into carbon dioxide and water vapour. This addition augments the existing advanced air pollution control equipment at the plant such as dry lime reactors and electrostatic precipitators.

At Senoko, the staff formed a Six Sigma team to systematically reduce the amount of electricity consumed in-house.

The team identified seven major groups of electrical equipment for optimisation. After a series of fine-tuning, energy consumption was reduced to the point where the plant saw its amount of electricity exported jump by about 8.9 million kWh per annum, or $740,000 at prevailing prices at that point.
Five Facts About Our WTEPs
   
 
1. NEA’s incineration plants are not just“rubbish burning facilities”. Our plants are sophisticated waste-to-energy facilities: they capture the energy embedded in materials like paper, leather, plastics, rubber, wood scraps and food scraps, and use the energy to generate electricity.

2. The incineration process that recovers energy for electricity production helps reduce global warming by eliminating the production of methane. If rubbish is allowed to decompose in landfills, significant amounts of methane will be generated. Methane has a global warming potential over 20 times that of carbon dioxide.

3. The incineration process at our state-ofthe- art facilities reduces waste volume by 90% and, in the process, converts the solid wastes into carbon dioxide, water vapour and inert ash.

4. The waste-to-energy process, alongside with waste minimisation, makes it possible for the Semakau Landfill to last beyond 2040 at the current waste generation rate.

5. Singapore’s experience with incineration started as far back as 1978 when Ulu Pandan WTEP was first commissioned. Twenty-nine years on, the plant is still operating well, treating more than 292,000 tonnes of waste in 2006 and generating about 60,000MWh of electricity, which is enough to light up 960 blocks of HDB flats every day for a whole year.
 
   
 
1999 756.2 2,036.3 2,792.5
2001 251.3 2,550.9 2,802.2
2003 193.8 2,311.2 2,505.0
2005 270.1 2,278.6 2,548.7

*waste landfilled includes non-incinerable wastes such as construction and demolition waste, used slag and treated sludge, and excludes incineration ash generated from waste disposed through incineration.