BioCycle December 2009, Vol. 50, No. 12, p. 48
An overview of MSW composting processes and projects in Australia, including basic funding structures used.
THE LAST QUARTER of 2009 represents the tenth anniversary of Australia’s first municipal solid waste (MSW) composting facility. It seems appropriate at this juncture to review the successes and failures over that period of time.
With a population of approximately 22 million and covering an area of 7.6 million square kilometres, Australia is divided into eight states and territories. The primary focus for waste processing implementation has been in New South Wales (population 7.1 million) and Western Australia (2.2 million) with an additional example in Queensland (4.3 million).
When compared to the U.S., with a population of 304 million and an area of 9.1 million square kilometres, Australia has a small population and a particularly low population density. This lack of population density however has not acted as a deterrent to improving waste management practices across Australia. Installed facilities, and those within the approvals process, yield by state a metric ton (mt) per capita processing ratio as follows: Western Australia, 0.150 mt per capita; New South Wales, 0.086 mt per capita; and Queensland, 0.023 mt per capita.
Drivers For Waste Processing
While it is recognized by the various agencies that landfills will continue to have an important role in waste management in the near to medium term future, similar to many countries, the establishment of new landfills in Australia has become difficult. Additionally state government agencies have used pricing mechanisms to make landfills a choice of last resort. These include whole of life costs, the setting of diversion targets (66 percent in NSW) and imposition of landfill levies ($60AUD/metric ton in NSW). Recent changes have also included the costs of greenhouse gas (GHG) impacts from landfills. A white paper released by the Federal government in late 2008 detailed the Carbon Pollution Reduction Scheme (CPRS) starting from July 1, 2010 and confirmed the inclusion of landfills.
Currently, the Australian Greenhouse Office calculates 900kg/CO2e is emitted for every metric ton of MSW landfilled. The net difference when comparing landfills with alternative processing will vary with waste inputs and processing technology, but generally even when accounting for waste processing energy inputs the impact will be reduced to 125 to 150kg/CO2e.
The current market based scheme for carbon credits in Australia has recorded $10AUD/metric ton. Speculation in regard to the Federal government’s CPRS has placed future costs at between $10AUD/metric ton to $30AUD/metric ton, significantly increasing landfill costs.
The delivery system favored by most regions (14 out of 15 cited facilities) is the Build Own Operate (BOO) model, where the successful tenderer wins the right to build and operate the facility for a term, typically 20 to 25 years. The facility remains the property of the proponent and the construction cost is carried by the proponent.
Commonly, this type of delivery and the associated financing requires the foundation of a Special Purpose Vehicle Company (SPV). The SPV attracts nonrecourse finance (the project is assessed, not the tenderer). The project viability therefore becomes a combination of the tariff (gate fee) and the council’s ability to pay. Additionally the SPV protects the council from proponent company collapse.
The financiers commonly require step in provisions through a tripartite agreement to safeguard their interests should the SPV become insolvent.
The First Installation
During the 1990s, planning and research into future waste disposal options for Port Stephens Council recommended a green field landfill site at the edge of the local government area. In planning for a new landfill site, the Council released an Expression of Interest for waste disposal services. One of the respondents was a rotating drum technology submitted by Bedminster Bioconversions Pty Ltd.
Further research and investigations led to a community consultation process that aimed to engage public understanding of alternative waste processing technologies before Council made any decision on adopting such technologies. In 1995, the New South Wales Government introduced the Waste Minimization and Management Act 1995, which at its core set an ambitious target for the state of a 60 percent reduction in waste to landfill by 2000 compared to 1990 levels.
In 1996, the Council released an open tender for waste processing and disposal services using advanced waste technologies. A number of technologies were mooted by various companies, and investigations by Council staff and Councilors resulted in Bedminster Bioconversions Australasia Pty Ltd. being awarded the contract in 1998 for its cocomposting system. Australia’s first long-term waste disposal agreement based on partnership principles using advanced waste technology was established in 1998.
Since its commissioning in 1999, the Bedminster cocomposting facility at Raymond Terrace, New South Wales (NSW) has processed more than 215,000 metric tons of MSW from Port Stephens Council. Over its lifespan the facility has a resource recovery rate of 55 percent.
A community satisfaction survey conducted by the Hunter Valley Research Foundation in 1992 and 1996 showed that waste management and recycling was second only to roads in the level of importance to the Port Stephens community. The same survey revealed that the majority of the community was highly dissatisfied with the management of waste and recycling by the Council at this time.
The survey was conducted again in 2000 (post-processing installation) and saw community satisfaction jump from highly dissatisfied to highly satisfied. In 2009, the survey revealed that 96 percent of the community rates waste and recycling services as the most critically important service, and 79 percent are very satisfied with the waste and recycling services.
The Bedminster two-stage aerobic composting system begins with biodegradable separation in the segmented in-vessel rotating drum over three days. After primary screening, the second stage (maturation) is achieved by controlled “open windrowing” within an enclosed structure. The combined system produces compost for commercial sale, metals for recycling and residuals for landfill. The facility is at the 10-year point of a 20-year contract and is currently being subject to “mid-life” sequential refurbishment of the rotary drums.
The Latest Installations
The Conporec and Dicom systems represent the most recent examples being implemented in Australia. The Conporec system located in Northern Perth, Western Australia (WA) services the Mindarie Regional Council (MRC). MRC, the state’s largest waste management authority, manages the disposal of waste generated each year by some 500,000 people, has a 20-year BOO contract for the establishment and operation of a 100,000 metric tons per annum (tpa) Conporec technology MSW composting facility. The $80 AUD million facility was completed in mid 2009.
Conporec’s two-stage aerobic composting system begins with the continual flow in-vessel rotating drum, over a three-day period. After primary screening, the second stage (maturation) is undertaken in an automated agitated channel system within an enclosed structure. The combined system produces compost, reclaimed metals and residual for landfills.
The locally developed Dicom process in Perth is of particular interest. The Dicom technology located at the Western Metropolitan Regional Council (WMRC) waste transfer station at Shenton Park, WA is a three-part process consisting of mechanical screening to separate organic/inorganic fractions, followed by combined (one vessel) aerobic/anaerobic digestion of the organic fraction, finally followed by screening and composting of organics.
The recent (August 2009) completion of three performance trials facilitates upsizing to commercial scale. In each of these trials the facility has processed all of the MSW delivered to the Shenton Park transfer station collected during one week by WMRC. The MSW is processed in the facility’s sorting plants, where the organic fraction is recovered from the general waste and loaded into the Dicom vessel. It is then converted by the 21 day hybrid aerobic/anaerobic Dicom bioconversion process into methane biogas and compost.
During the thermophilic anaerobic phase of the Dicom bioconversion process, anaerobic liquid was recirculated through the organic material at temperatures averaging over 55°C (131°F) and consistently produced biogas with a methane content of 55 percent or higher over a 7-day period. The significance of the methane content means that the biogas can be burnt using conventional gas engines without the requirement of further concentration treatment. With the successful conclusion of the trials, the facility will be upsized to 55,000 tpa.
In NSW, either individual or council groupings are currently pursuing an additional processing capacity of 230,000 tpa. Similarly, in WA an additional capacity of 250,000 tpa is being sought.
In Victoria, a contract for processing 80,000 tpa of waste (the state’s first) was successfully tendered by the Dicom technology; however the contract is subject to a successful outcome at the Perth facility.
The various states have adopted different strategies to encourage the uptake of alternative waste processing. It is noteworthy that WA with a landfill levy of only $8AUD/metric ton and significantly lower disposal charges than NSW still has achieved nearly double the per capita installation rate. The optimal mix of political guidance, delivery structures, market forces and the levy level remains unresolved.
One factor that appears to be constant across Australia is that there is strong community support for environmentally effective solutions to waste management. This has been further reinforced with issues surrounding climate change.
Paul Oakes is Director of Quadro Australia Pty Ltd., which provides services for innovative waste management, infrastructure delivery and process improvement. He can be reached at firstname.lastname@example.org.
December 15, 2009 | General
Municipal Solid Waste Processing (Australia)
BioCycle December 2009, Vol. 50, No. 12, p. 48