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

20031970

The Solid Waste Challenge

WasteExplosion

1,200 t/d1,200 t/d

6,900 t/d6,900 t/d

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

Collection

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 MethodDirect CollectionDoor-to-door collection from landed properties and shop houses

Collection MethodIndirect Collection : Bin Centre

Collection at bin chute Transferring of refuse

Loading into compactorTowing away compactor

Indirect CollectionCentralised Refuse Chute (CRC)

Collection Method

The route

REFUSE DISPOSAL FACILITIESREFUSE DISPOSAL FACILITIES

National Recycling Programme

• 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

Door-to-Door Collection

Common Recyclable Materials

• Paper• Drink cans• Glass bottles/jars• Plastic bottles• Carton boxes

Household Participation Rate

• 15% in Apr 2001

• 33% in 2002

• 45% in 2003

Recycling Bins at Public Places

• MRT Stations• Bus-interchanges• Changi Airport• Shopping Malls

Recycling Bins along Orchard Road

Glass Bell at Camden Park

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

e-Waste Recycling

Construction & Demolition Waste Recycling

Copper Slag Recycling

Paving Bricks

Processing of Used Copper Slag

Plastic Waste Recycling

Plastic scraps

Plastic Pellets

Heating and Extrusion

Pelletised Animal Feed

Recycling Process

Food Waste Recycling

Spent Soya Bean

NEA’s Target

To increase current recycling rate of

47% to 60%

by 2012

Disposal

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

Tuas South Incineration Plant

Tuas South Incineration Plant

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

Tuas Marine Transfer StationTuas Marine Transfer Station

Tipping of WasteTipping of Waste

TuasTuas Marine Transfer StationMarine Transfer Station

Full BargeFull Barge

TuasTuas Marine Transfer StationMarine Transfer 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

Unloading of wasteUnloading of waste

SEMAKAU LANDFILLSEMAKAU LANDFILL

Loading onto dump truckLoading onto dump truck

SEMAKAU LANDFILLSEMAKAU LANDFILL

Tipping SiteTipping Site

SEMAKAU LANDFILLSEMAKAU LANDFILL

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

12

Pavement Block from MSW Fly Ash

Marine Clay

Brick Product

Fly Ash

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

Disposal Fee

$81Senoko IPUlu Pandan IP

$77Tuas IPTuas South IPSemakau Landfill

Disposal Fee(per tonne)

Disposal Site