The Waste 2011 conference came to a successful close last Thursday after more than 400 people had been through the doors to see the exhibition and attend conference sessions which featured a comprehensive selection of speakers from industry and government. As part of the conference, the Local Government Innovation in Waste Awards were presented, with Great Lakes Council taking out top honours.
Organiser of the conference, Greg Freeman, said, “What’s impressive about the conference is that we’re trying to have an outreach into Southeast Asia…to see what our neighbours are doing”.
This year, the conference sponsored Sarifah bt Yaacob, an executive committee member of the Waste Management Association of Malaysia, who spoke on the challenges in solid waste management in Malaysia. There was also a pre-recorded presentation from the Municipality of Oslo’s agency for waste management discussing the subject of organic waste and energy.
“It’s strongly attended by local government,” said Freeman, “which we have a history of, as well as strong corporate support”.
This was reflected in the program, with streams dedicated to food waste and organics; tendering and contracts; education and communication; Waste to Energy (WtE) and Alternative Waste Technologies (AWTs).
“There was a really good session that we did on strategies, targets and levies which assembled government representatives from every main state and national,” said Freeman, “It was looking at all these economic levers and whether they are getting us anywhere”.
Speaking in the WtE stream, Coffey Environments’ Pablo Perez-Reigosa spoke on the emerging trends in WtE in Europe and its increasing role in the overall management of wastes.
“The broad experiences of Europe in this field provide a good model which can be applicable to waste management and resource recovery in Australia,” said Perez-Reigosa.
The percentage of municipal wastes in the European Union (EU) treated by WtE has been steadily increasing from 16% since 2000 to 20 % by 2008. Similarly, the percentage of wastes sent for recycling, which includes composting, has increased from 27% in 2000 to 40% in 2008.
In contrast to the aforementioned results, the percentage of wastes sent to landfill has decreased from 58% in 2000, to 40% in 2008.
The countries with the greatest proportion of their municipal waste sent to WtE plants were Denmark (54%) and Sweden (49%). The countries with the greatest proportion of wastes sent for recycling were Austria (69%) and Germany (65%).
“Waste-to-Energy is widely-accepted as falling into the energy recovery category under the waste management hierarchy and has been successful across Europe,” said Perez-Reigosa.
While the use of AWT treatment/pre-treatment is commonly acknowledged by industry to reduce the landfill gas generation potential of the treated waste, only limited studies have so far been released which look at the magnitude of these reductions.
Matt Welsh, spoke to delegates about GHD’s investigations into this area which have unearthed some interesting findings.
He explained that treatment/pre-treatment of organic wastes does generally not reduce the landfill gas (LFG) generation potential to zero due to operational limitations (most importantly treatment time).
“International papers suggest that only a 40 to 60% reduction in landfill gas generation potential is achieved,” said Welsh.
The reduction in LFG generation potential means that landfill sites which are treating/pre-treating their organic wastes are likely to be less viable for LFG power generation projects under current conditions (as less LFG will be generated at the site), according to Welsh.
Current LFG emission models adopted by the Commonwealth DCCEE (NGER Solid Waste Calculator 1.6) are not really able to account for altered waste input compositions for AWT treated materials and specific DOC/k values etc. used within the model are not available for AWT treated/pre-treated waste streams.
“If a council intends to treat/pre-treat waste using AWT and subsequently landfill the residues, it is important to be aware that there will still be LFG to manage,” said Welsh.
He said in order to maximise the benefit from the treatment process from a carbon tax perspective, testing of the input waste stream to define its LFG generation potential will be required so that the prepared model does not over estimate LFG generation and emissions (and therefore the council’s exposure to a carbon tax or ETS).
An estimated 680,000 tpa of MSW is still being landfilled in the top 30 waste generating councils in NSW and 40% of this (272,000 tpa) is food organics. But this MSW also contains: 20% (136,000 tpa) of paper; 11% (75,000 tpa) of compostable organics; 10% (68,000 tpa) of plastics; 5 % (34,000 tpa) of other organics; 4% (27,000 tpa) of glass; and 3% (20,000 tpa) of metals.
“Upwards of 90% of the contents of the average MSW bin are potentially recoverable,” said GHD’s David Gamble, “Improving existing recycling is the first step in recovering the non organic materials, then AWT to recover other resources”.
He said separate food organics collection and treatment is the preferred method for organics as it’s simple, cheap, reliable, accessible and makes a marketable product.
“In some situations, separate food organics collection/treatment can be difficult due to contamination issues and collection logistics,” said Gamble.
Furthermore, contamination of food organics is likely in areas with high non-English speaking populations and transient tenants.
Historically waste education has been about disseminating information such as stickers, brochures/flyers, newspapers ads and posters. It has assumed that if you give people information they will change their behaviour.
With a population of 186,000 people, Bankstown is home to many migrants, with up to 43% of the community born overseas and 51% speaking a language other than English at home.
With contamination levels in its general recycling of up to 30%, council’s co-ordinator of resource recovery, Daniela Santucci, conducted extensive research and trials to find a more effective means of creating behaviour change.
What the research showed was that the council needed to provide more than information; it needed to work on barriers and behaviours one at a time; it needed to “play with people’s minds” to make them recycle right.
“So, we commenced the development of the campaign and developed awareness and feedback material,” said Santucci, which incorporated what they had learned in regard to positive and encouraging messages.
What the trials showed was that in houses, the right type of feedback will motivate most people to recycle right, but sometimes more is needed.
In multi-unit dwellings, feedback alone does not work as it needs to be coupled with other elements possibly verbal feedback.
The council’s strongest multi-unit dwelling trials, where pledges were displayed from units that had made a commitment not to put plastic bags in the recycling bin, had a 24% reduction in contamination.
Areas where feedback posters were provided in letterboxes and bin bay areas had a reduction of 18%; and areas where bins lids where changed to lids with a square hole had a 25% reduction.
