War on waste: diverting landfill to make electricity
Western Australia is set for a waste-to-energy revolution as council waste is diverted from landfill and the energy converted to power homes
Even the most devoted recycling, composting, e-waste conscious households will end up with some rubbish in their council bin, and there are still many who don’t sort their waste to such high standards. Landfill has many problems as a waste solution, including leaching into the water table. The French even doubt that landfill is a solution as they name it “stockage” which translates to “storage. And many countries that previously accepted shipments of Australia’s waste have put up the shutters. More sustainable solutions are required.
“Landfill is just throwing our waste down a few generations into the future,” says Dr Marc Stammbach, managing director of the Australian arm of Swiss cleantech company Hitachi Zosen Inova (HZI). “It’s like telling our grandchildren, ‘Good luck with that’, because we know that it will be a contaminated site and at some stage they will have to dig it up and clean it up.”
Sustainable, environmentally conscious solutions to deal with waste are critical to both diverting waste from landfill and reducing emissions of greenhouse gases. Innovative technology that does just that is set to swing into action in 2022 in WA at the East Rockingham Waste-to-Energy facility, 45km south of Perth.
HZI’s proven thermal EfW (energy from waste) solution is at the heart of the $511 million project, which will use ABB ACF5000 multi-component gas analyzer system to ensure the operation meets all EPA standards.
The EfW plant will generate 29MW of electricity for the state-owned grid, enough to power 40,000 homes from up to 330,000 tonnes of municipal, industrial and commercial waste that will come to the site as feedstock for the conversion process.
“We are converting waste which would otherwise go to landfill to thermal energy,” explains Stammbach, who stresses that people should first prioritise recycling, composting and proper disposal of e-waste such as electronics and batteries. “We burn the waste on a moving grate, which results in hot flue gas, which converts that energy into steam which is then turned into electricity to supply households and industry with power.”
It’s critical to “clean up” the flue gas, he explains, “to a very high level, to ensure there are no concerns for the environment”. About 4% of the residues from the cleaned flue gas will eventually go to landfill, but the ash from the incineration is recycled for use in road construction. Metals are retrieved from the byproduct and reintegrated into the metal smelting industry. “We’re closing the circle,” says Stammbach. “We will probably be the smallest mine in Western Australia as we mine for those metals to recycle!”
The EfW process ensures that 96% of the waste that comes through the plant is diverted from landfill. This is particularly important for Perth, which sits on a sandy coastal plain. Groundwater is the primary water source for the population, meaning that as existing landfill sites reach capacity, new sites are unlikely to be approved, at least in metropolitan areas (and given that Asian countries are saying no, it’s unlikely any regions will be putting up their hand to receive city waste).
The waste that comes into the plant is, as Stammbach explains, “everything you don’t want, and when we receive it, we don’t know what’s inside”. Waste from council rubbish collections or industry is combined in a bunker, where a crane mixes it. “That helps to equalise and homogenise the waste,” says Stammbach. “But even then when we burn it, it can change by the minute, depending on what’s coming in, which is why we need emissions monitoring technology to constantly analyse the gas”.
Three ABB ACF5000 analyzers running ABB Ability Condition Monitoring software were selected for this critical task. The analyzers are made in Germany and will be programmed, wired and plumbed at ABB’s Moorebank site to HZI’s specifications, ready for delivery in their own housing, in a structure about the size of a shipping container. Once on-site in WA, the gas inlet is connected to the main plant, the analyzers are hooked up to the power and it’s ready for 24/7 monitoring. “The ABB system is an integral part of the operation and an important tool for stakeholder information, too,” says Stammbach.
ABB’s ability to monitor the system remotely was key to its technology being selected for the project. ABB’s expert engineers will be able to check that everything’s running smoothly without visiting the site, via remote access secured by world-class cybersecurity technologies. ABB has a service team based in Perth who will be on-site during commissioning and start-up and available as required. The combination of ABB’s analytics, local capabilities and deep domain expertise means we can contribute across the value chain from engineering to project execution to support for the life of the plant.
HZI’s Stammbach acknowledges the hesitancy of some governments to embrace the energy-to-waste technology that his company has spent decades perfecting, believing that waste disposal combined with energy production is a global need. “We have to overcome a lot of ignorance, a lot of resistance and a lot of emotion,” he says frankly. “People realise climate change is an issue, and waste is a part of that – and it’s an issue on its own in terms of environmental pollution.”
He says that the continuing innovation of smaller and multi-composite electronics will continue to make waste disposal challenging, and that over the life of the East Rockingham plant, the materials in the waste they process will definitely change – another reason monitoring of the gas is critical. “We will have waste where it’s difficult to distinguish if it’s plastic or metal, and which metal, or glass,” he says. “There are more and more toys and electrical things out there – even Christmas cards come with chips for recordings.”
HZI’s position is that this waste is a lost resource if it is sent to landfill, as well as an unsustainable solution. “You lose energy, you lose materials and we cannot afford to continue doing that,” says Stammbach. “The triple benefit of burning it is you get the energy, you avoid greenhouse gas emissions and you avoid leaching issues with landfill. We are only at the start of energy-to-waste in Australia. We need at least 20-30 more plants across the country.”
Europe has embraced the technology and has targets to support it. “In Europe, you either compost, recycle or burn it,” says Stammbach. “The current discussion in the EU is to reach 65% of waste goes to compost or recycling, less than 10% to landfill, which leaves 25% for burning, or waste to energy. Waste is a problem worldwide, and if you are affluent as we are in Australia, you have the option to do what we’re doing with waste to energy, and we should consider helping our less-affluent neighbours, too.”
Safely turning waste that can’t be otherwise recycled or composted into electricity is an inspiring solution for the planet.