Waste Management and WasteWaste Management and Waste--toto--Energy Energy Status in SingaporeStatus in Singapore
Lawrence C. C.Lawrence C. C. KoeKoe, J. Y. Wang, and H.B. Ding, J. Y. Wang, and H.B. DingEnvironmental Engineering Research Environmental Engineering Research CenterCenter
NanyangNanyang Technological UniversityTechnological UniversitySingaporeSingapore
Singapore: A Green City State• Green and Clean
• Tropical climate: Warm (26 – 34 C) and Humid (60 – 90%)
• Area: 680 km2
• Rainfall: 2400 mm/year
• Population: 4 millions
• Multiple races
Water and Wastewater • Water demand: 1.3 Million m3 per day
• 50% from rainfall + 50% from Malaysia
• 6 water treatment plants
• Wastewater treatment: 1.1 Million m3 per day (50/50 for household/industry)
• 6 wastewater treatment plants (water reclamation plants); Newater
Singapore’s Waste Management
• In 2003, 6877 tonnes/day (2.51 M tonnes/year) of MSW collected for disposal (0.94 kg/c/d)
• 57.3% (household) Vs 42.7% (industry)
• 92% was disposed of at the 4 incineration plants
• 8% (non-incinerable waste) and incineration ash goes to the offshore Semakau Landfill
• To reach 60% recycling rate by 2012; current recycling rate = 47% with 40% from industry
Waste Management Strategy• Towards Zero Landfill• Towards Zero Waste
• 1. Incineration• 2. Recycling• 3. Reuse• 4. Waste minimisation
1970 TraditionalLandfill
2003
VolumeReduction
Incineration Bottom Ash (IBA)Non-incinerable Waste
• One IP every 5-7 years• One landfill the size of
Sentosa every 25-30 years
Strategy 1 : IncinerationStrategy 1 : Incineration
Recycling of Industrial WasteRecycling of Industrial Waste
ConstrConstr. & Demolition waste. & Demolition wasteHorticultural waste Horticultural waste
Copper slagCopper slagPlastic wastePlastic wasteWood wasteWood waste
1970 2003 TraditionalLandfill
Strategy 2 : RecyclingStrategy 2 : Recycling
Recycling in CommunityRecycling in Community
HouseholdsHouseholdsCondominiumsCondominiumsShopping mallsShopping mallsTrade PremisesTrade Premises
1970 2003 TraditionalLandfill
Strategy 2 : RecyclingStrategy 2 : Recycling
Reuse of Incineration Bottom AshReuse of Incineration Bottom AshRecycling of nonRecycling of non--incinerableincinerable wastewaste
ReduceLandfill
1970 2003 TraditionalLandfill
Strategy 3 : Reduce Waste To LandfillStrategy 3 : Reduce Waste To Landfill
TOWARDS ZERO LANDFILLTOWARDS ZERO LANDFILL
ReduceLandfill
1970 2003 TraditionalLandfill
MinimiseMinimise waste at sourcewaste at source
Design with less packagingDesign with less packaging
Use less packaging Use less packaging
Use packaging that can be Use packaging that can be recycledrecycled
Strategy 4 : Waste Strategy 4 : Waste MinimisationMinimisation
TOWARDS ZERO WASTE
Overall Waste Recycling Rate
40
47
35
40
45
50
55
60
65
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012Year
Pe
rce
nt
6060
• Lifespan of Semakau landfill
25-30 years to 35-40 years
• Need for additional Incineration Plant (IP)
5-7 years to 8-10 years
Outcome
MSW Composition (2003)• Food waste 20.6% Used slag 0.87%
• Paper/cardboard 24.7% Sludge 3.5%
• Plastics 21.6% Glass 2.4%
• Construction debris 0.98% Textile/Leather 3.6%
• Wood/Timber 6.9% Scrap tyres 0.3%
• Horticultural waste 7.4% Others 4.1%
• Ferrous metals 2.3%
• Non-ferrous metals 0.72%
MSW Characteristics for SG
• Net calorific value (kj/kg) = 6750 (4000 - 9000)
• Water content (% weight) = 48.6 (40 - 65)
• Non-incinerables (% weight) = 8 (5 - 1.5)
SW Composition (SG vs US)(1999)
• Food waste, garden waste 44.4 : 27.5
• Paper, cardboard, and wood 28.3 : 42
• Glass 4.1 : 8
• Metals 4.8 : 9.5
• Plastics 11.8 : 7.0
• Textiles, leather and rubber 3.0 : 3.0
• Ceramics and residues 3.2 : 3.0
Domestic & Trade Premises– Service privatised since Sep 01– 9 sectors - waste collected by Public
Waste Collectors (4)– Improve collection efficiency and
service quality
Industrial & Commercial Premises– Engage their own waste collectors
Collection
Boundaries of the 9 Sectors
Bedok
Jurong
Clementi City
Tanglin-Bukit Merah
Ang Mo Kio-Toa Payoh
Hougang-PunggolWoodlandsWoodlands--
YishunYishun
3
4
9
5 6
8
7
2
Pasir Ris-Tampines
1
Collection MethodIndirect Collection : Bin Centre
Collection at bin chute Transferring of refuse
Loading into compactorTowing away compactor
• A structured and organised recycling programme for domestic households
• PWCs collect recyclables door-to-door in their sectors every fortnight
• Residents given plastic bags/recycling bins/trays
National Recycling Programme
New Material Recovery Facility
• SembVisy’s Material Recovery Facility
• Semi-automated sorting plant opened in Nov 02– capacity to sort 50
tonnes/day of recyclables e.g. paper and cardboard, plastics, glass and cans
Wood Waste Recycling
Recycling of wood waste to produce• Office furniture• Home furniture• Pallets
Shredded Wood Waste
LORONG HALUS DUMPING GROUNDLORONG HALUS DUMPING GROUND(closed on 31 Mar 1999)(closed on 31 Mar 1999)
• 92% of waste is disposed of by incineration
• Volume of waste is reduced by 90%
• Energy is recovered for electricity generation• 981 million kWh of electricity generated • 2 to 3% of the electricity demand for Singapore
• Scrap metal is recovered for recycling• 22,800 tons of scrap recovered
Disposal - Incineration
Incineration Plants
Senoko IPSenoko IP
Tuas Tuas South IPSouth IP
Tuas IPTuas IP UluUlu PandanPandanIPIP
Incineration Capacities
8,200Total
3,0002000Tuas South
2,4001992Senoko
1,7001986Tuas
1,1001979Ulu Pandan
Capacity(tonnes/day)
Year CommissionedIP
Table 2. Construction of incineration plants Name of incineration plant Year Construction cost Capacity (tonnes/d) Ulu Pandan Incineration Plant 1979 S$ 130 million 1,100 Tuas Incineration Plant 1986 S$ 200 million 1,700 Senoko Incineration Plant 1992 S$ 560 million 2,400 Tuas South Incineration Plant 2000 S$ 900 million 3,000
Features of the Tuas South Incineration Plant
• Independent modules: 6 incinerators (500 tonne/day each); total capacity is 3000 tonne/day
• Power generation capacity = 80 MW• 20% of the power recovered for in-plant use; the
rest is sold to power grid; scrap metals sold• Volume reduction (~ 90%)• Weight reduction (70 - 75%)• Main contractor: Mitsubishi Co.• Main consultant: Fichtner Co.• Total capital cost = S$900 millions
• Disposal of 10% non-incinerablewaste
• 1,400 tonnes/day IBA
• Commenced operation on 1 Apr 99
• Capacity : 63 million m3
• Area : 350 ha
Semakau Landfill
Semakau Landfill
SemakauSemakauLandfillLandfill
TuasTuas Marine Marine Transfer StationTransfer Station
Closing of Hatch CoverClosing of Hatch Cover
TuasTuas Marine Transfer StationMarine Transfer Station
Waste is brought Waste is brought by barge to the by barge to the
receiving stationreceiving station
SEMAKAU LANDFILLSEMAKAU LANDFILL
MSW Research Work @EERC• Bioconversion of food waste into biogas and biofertilizer
• Bioconversion of dewatered sewage sludge and food waste into biofertilizer
• Bioconversion of horticultural waste and food waste into a new soil substitute
• Pyrolytic conversion of plastic waste into fuel and monomers
• Use of ladle furnace slag (by product of steel making) for asphalt production
• Use of incineration fly ash and marine clay as construction materials
FOOD WASTE CONVERSIONFOOD WASTE CONVERSION• Research goal is to convert food waste into
value-added products, e.g., compost, fertiliser,or methane gas
1/5 (S1) 5/5
1/5
5/5
4/5(S2)
acidification methanogenic reactor reactor
wet gasmeter
peristalticpump
The two-phase batch reactor system
ORGANIC SOLID WASTEORGANIC SOLID WASTECONVERSION & CODISPOSAL CONVERSION & CODISPOSAL
• Conversion of sewage sludge and food waste intobiofertilizer using an enhanced high-rate bioconversion technology
Fees for 9 Sectors
$17.01 ~ $26.70Landed$7.21 ~ $8.97Apartments
Fees per MonthDomestic Premises
$434.60 ~ $629.40660 to <1100 litres/day$286.55 ~ $362.67360 to < 660 litres/day$120.75 ~ $210.20240 to < 360 litres/day$56.70 ~ $135.45120 to < 240 litres/day$22.20 ~ $47.78< 120 litres/day
Trade Premises