Land-scarce Singapore’s recycling rate is enviable but to increase to over 60% by 2012, without a landfill tax, will require more innovation. Following the World Cities Summit, Jeff Cooper - vice president of ISWA - took the opportunity to investigate the country’s ambitious recycling and waste management plans, and to attend the opening of its latest WtE facility.
Singapore has a population of 4.8 million, a high population density of 6500 people per km2 and very limited natural resources. It therefore has a huge incentive to ensure that it addresses sustainable resource management.
When the Singapore Green Plan 2012 was adopted in 2006, the country wanted to follow the principles of the waste hierarchy in order to ensure that Singapore’s non-recoverable waste was reduced to an absolute minimum, explains Vaneeta Bhojwani, deputy director for the Industry Development and Promotion Office of the National Environment Agency (NEA) of Singapore. However, she goes onto exaplain, the main target was to reach a 60% recycling rate for the island’s waste by 2012.
Singapore has prioritised waste minimisation to reduce the amount of waste generated, especially from the household sector, although the scope for doing so is quite limited in comparison with EU countries. The first priority was to reach a voluntary agreement with the food and beverage and packaging industries to reduce the amount of packaging generated.
The national recycling programme is a voluntary recycling programme for households and trade premises. Recycling bags and bins are provided for the storage of recyclables which are collected fortnightly. In this way, most of the population has the opportunity to participate and 63% of the households do, although household waste recovery rates are only 13%.
In 2001 Singapore decided to change the previous system whereby the State, through the NEA undertook the collection of household waste (and its disposal) by contracting out the operation. Bids were sought for nine areas within Singapore for daily household waste collections and a fortnightly collection of dry recyclable wastes. Four of the contracts are held by a local company, formed from the rump of the old state waste collection enterprise, three were held by SULO, now taken over by Veolia, and the other two by local companies.
|Mr Teo Chee Hean, Deputy Prime Minister of Singapore is among the government officials getting an overview of the Keppel Seghers Tuas WTE Plant|
The problem with fortnightly collections of recyclable wastes from Singapore’s predominantly high rise housing is the time and effort needed to collect the wastes. Therefore in several cases this operation is sub-contracted out. Either the sub-contractor is paid for the tonnage of recyclable wastes collected and supplies the bags or the subcontractor is paid a fee for servicing the households and the bags are supplied to the sub-contractor.
For industrial and commercial wastes there are a variety of recycling initiatives that have been developed by local companies, including the composting of horticultural wastes. Wood wastes are shredded to make particle board achieving a 37% recycling rate, however, plastics only achieve a 12% rate.
Construction and demolition (C&D) waste comprises mainly non-incinerable materials. The NEA charges S$77 (US$57) per tonne for waste disposed and this provides an incentive for C&D companies to cut costs by reducing waste through better work processes such as the segregation of waste for recycling.
The NEA has also facilitated the setting up of C&D waste recycling facilities by ensuring that land is available to set up recycling plants, and providing funding support for test-bedding new technologies under the Innovation for Environmental Sustainability Fund. The recycling rate exceeds 90% and even ‘slag’, shot blasting materials used in the shipping maintenance and repair sector, is being re-utilised.
In 2006 the overall Singapore recycling rate was 51%, this rose to 54% in 2007 and 56% by 2008 according to the NEA’s Annual Report for 2008/09. Singapore hopes to increase this further, partly through the recovery of the 1500 tonnes per day (tpd) of IBA (incinerator bottom ash). A pilot plant for IBA processing has been built, partly aided by a research grant from the government, to evaluate the best options.
During 2008 the move towards greater reprocessing and re-utilisation of C&D wastes was given a considerable boost when Indonesia decided that it would no longer send aggregates to Singapore.
Raising the recycling rate beyond its Green Plan target of 60% by 2012 will be difficult because unlike many EU countries and Australian States, in Singapore there is no landfill tax.
While state intervention is limited it is helping to push more waste up the hierarchy. Therefore any waste that is combustible has to go into one of the island’s incineration plants, all of which were until recently owned and managed by the state, and the cost is S$77 ($57) per tonne. Of the 7000 tpd presented for incineration, 57% comes from households and only 43% from commerce and industry.
Singapore’s fifth incinerator was officially opened in June 2010. It was significant in two ways: it is the first incineration plant to be built and operated by the private sector in Singapore and the first to be smaller than each of its predecessors. Indeed, it is smallest MSW incineration plant ever built in Singapore.
Under Singapore’s policy to encourage greater private sector investment an international tender for a design, build and operate contract for a new WtE facility was announced in 2005 under the NEA’s Public-Private Partnership (PPP) initiative. A local company, Keppel Seghers won the 25-year contract for the 800 tonnes per day incineration plant. The plant can generate up to 20 MW of renewable energy to go into the national grid.
The new Tuas incineration plant
Due to Singapore’s success in recycling more wastes and its first efforts at waste prevention, the first of Singapore’s waste incineration plants has now been replaced. The newly opened plant’s design capacity is even lower than Singapore’s first plant at 800 tpd through the NEA’s design, build and operate contract. The new Keppel Seghers’ Tuas plant became fully operational in October 2009 after its successful commissioning trials. The reason for Singapore choosing incineration as its primary method of waste treatment and disposal in the 1970s was emphasised by the deputy prime minister, Mr Teo Chee Hean in his speech when opening the new plant: “With just 700 km2 and a high population density Singapore needed to find an alternative to the land-intensive method of landfilling waste”.
This aspect of saving land resources in Singapore was further emphasised by Mr Michael Chia, the deputy chairman and CEO of KIE (Keppel Integrated Engineering, within which Keppel Seghers forms its environmental engineering arm), in his speech at the official opening. The plant occupies only 1.6 ha of land to “support NEA’s aim of building a sustainable quality environment in land-scarce Singapore by incorporating many space saving and technologically advanced features”.
One of the design features of the plant is the combustion grate configuration which allows effective mixing of the waste for efficient combustion through a mix of tiles (slats) within the grate, some of which are fixed and others capable of moving the waste in either one or two dimensions. According to Prof Jim Swithenbank from the Waste Incineration Centre based at Sheffield University, purely from visual inspection, the burn out of the waste was good with ash content probably having a very low carbon content.
Once the waste has been reduced to 10% of its original volume, the IBA is transported to Singapore’s only landfill, Semakau. This transfer is through the Tuas Marine Transfer Station which is integrated into the neighbouring South Tuas incinerator.
The Deputy Prime Minister takes a look into the furnace of Singapore’s newest incineration plant
The Semakau landfill site was constructed in the 1990s as a land reclamation project with a 7 km bund enclosing two small islands producing a 350 ha site with 63 million m3 capacity. Fully lined and carefully engineered it was initially expected to last Singapore for 20-25 years before a further landfill facility needed to be developed.
With the reduction of waste being sent for landfill, the Semakau site is now expected to last 35-50 years. This timeline ought to become potentially substantially longer if the IBA is recovered and utilised as a secondary aggregate.
With regard to the ultimate disposal routes, excluding the wastes sent for recycling, a mere 180,000 tonnes went directly to landfill in 2008 while 2.45 million tonnes went through the four incineration plants.
Outputs from the first four incineration plants include 1048 GWh of electricity generated in 2008. The amount is expected to increase slightly each year due to operational efficiencies within the incineration plants.
Overall, Singapore has an enviable waste management system - certainly comparable to the best that the EU can demonstrate. However, at present it stands as an isolated beacon in a region where the standards and regulations for waste management are still to be established, let alone implemented. Even within Singapore, however, there are many opportunities to enhance its progress to achieve the ambitious objectives incorporated into the Singapore Green Plan 2012.
- Jeff Cooper is vice president of the International Solid Waste Association (ISWA).