Letsrecycle.com 2 Jan 08;
In November 2008 Singapore will host the International Solid Waste Association annual congress. This article, by Jeff Cooper, president of the Chartered Institution of Wastes Management, looks at how far Singapore has progressed with its management of wastes.
In Singapore today, high proportions of waste are recycled and recovered and only minimal amounts landfilled. Even the waste currently going to landfill could in a short time be recycled.
Vaneeta Bhojwani, senior engineer in Singapore's resource conservation department of the National Environment Agency (NEA), explained that when Singapore Green Plan 2012 was adopted as its waste management strategy, it wanted to follow the principles of the waste hierarchy. However, the main target was to reach a 60% recycling rate for the island's waste by 2012.
Singapore has focused on waste minimisation, but had very limited powers to change the amounts of waste generated, especially from the household sector.
The first priority was to reach a voluntary agreement with retailers to reduce the amount of packaging given to households. Despite the limited amount of waste associated with the plastic carrier bag it is an iconic packaging product.
Following a successful initiative in April 2007 to stop handing out plastic bags Singapore's retailers have agreed that on the first Wednesday of every month they would institute a Bring Your Own Bag (BYOB) day. Members of the public can still have plastic bags, but they have to pay S$0.10 (£0.03) for each one. Recently, however, although there have been more retailers interested in joining the initiative among the public interest has waned. Therefore when reminding people that the next day is a BYOB day the reaction of many members of the public has been to stock up with extra bags on the previous Tuesday.
The national recycling programme pre-dates the Green Plan and again it is voluntary for households and businesses. Most of the island's population has the opportunity to participate in a fortnightly door-to-door collection of recyclable wastes and 86% of the households do.
In addition, there are 3,400 bring bins located throughout the island. These wastes are processed in two materials recycling facilities, but the reprocessing of the wastes mainly takes place elsewhere.
Collection
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.
The initial contracts were phased and were for a period of five years, and during 2006 the collection contracts were re-tendered for the first time for seven years, which will be the normal length of contract for the future. Four of the contracts are held by a local company, formed from the rump of the old state waste collection enterprise, three are held by SULO, now taken over by Veolia, and the other two are held by local companies.
Despite pressure to go over to less frequent servicing of households' residual waste in order to enhance the recycling collections and segregate further waste fractions to date, that has been resisted.
The problem with fortnightly collections of recyclable wastes from Singapore's predominant high rise housing units 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.
A further issue is the loss of recyclable wastes from the households, or more usually from the bank sites that are raided by local entrepreneurs because the value of the main secondary materials are high at the present time. However, at least it is being reclaimed and recycled.
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, and plastics are recycled but at only a 12% rate. Nevertheless the majority of the commercial and industrial plastics are processed on the island and are often made into new products as well.
For construction and demolition (C&D) waste the recycling rate exceeds 90% and even the "slag" - shot-blasting materials used in the shipping maintenance and repair sector - is being re-utilised.
Recovery
In 2006 the overall Singapore recycling rate was 51%. Singapore expects to increase this further through the recovery of the 1,500 tonnes per day 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.
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 are owned and managed by the state and the cost is S$77 (£26) per tonne. Of the 7,000 tpd presented for incineration 57% comes from households and only 43% from commerce and industry.
The island's four incineration plants were built between 1979 and 2000 with the capacity of each one getting bigger each time. The first had a capacity of 800 tonnes per day, then another with higher capacity of 1,100 tonnes, the third 2,400 tpd finally 3,000 tpd for the last in order to accommodate ever increasing amounts of waste. Now due to Singapore's success in recycling more wastes, the first plant is to be replaced at the same capacity, 800 tpd, through a design build and operate contract and due to become operational in 2009 or 2010.
Outputs from the incineration plant included 938m kWh of electricity in 2006, around 3% of the island's consumption and 14,000 tonnes of scrap metal each year. Through the success of its waste reduction and recycling measures Singapore will be able to extend the time for replacement of its other incineration plants. However, those plants are likely to be contracted out as the NEA devolves direct responsibility for waste disposal operations.
Landfill
On 31 March 1999 the last mainland landfill was shut down to be replaced by an offshore landfill. This necessitated the building of a barge transfer station at so that all the incineration plants' bottom ash can be shipped together with the modest amounts of industrial and C&D wastes.
The 4% of non-combustible waste, plus the IBA, is currently consigned to the island's only landfill, Semakau, which was constructed in the 1990s as a land reclamation project with a 7km bund enclosing 2 small islands producing a 350ha site with 63m m3 capacity. Fully lined and carefully engineered it was expected to last Singapore 20-25 years. With the reduction of waste being sent for landfill it is now expected to last 35-40 years and potentially substantially longer if the IBA is recovered.
The island landfill was split into two areas with the first sub-divided into 11 tipping areas, of which six have now been filled. The water in each area remains fresh until it is needed for filling at which point the concrete culverts are blocked off and the water pumped out prior to filling. The second area has yet to be subdivided but when that has been filled to sea level the first area will be raised to a maximum of 25m above sea level and then the second landscaped with four hillocks. This will create an open space for informal recreation, or at least that is the current plan.
Even now the landfill is now being opened up for a variety of leisure and recreational purposes, including sport fishing, bird watching, walking the inter-tidal zone and star gazing.
The International Solid Waste Association's 2008 Annual Congress takes place in Singapore from 3-6 November 2008. There will be site visits to the landfill site and other waste management and recycling facilities as part of the programme. Abstracts are invited for the event by 15 March 2008.
RELATED LINKS
Waste Management and Recycling Association of Singapore (WMRAS) Established on 8 Aug 01, WMRAS aims to professionalise and develop a leading waste management and recycling industry in Asia by promoting business networking opportunities and best practices amongst members, organising activities such as talks, mission trips, conferences, exhibitions and members get together sessions and regular dialogue sessions with relevant authorities.
International Solid Waste Association
