A cleaner future amid rising landfill costs and dangers
Piling food and beverage waste into landfill poses many hazards and high environmental and business costs. It releases toxins into the environment, leachate into water tables and high volumes of greenhouse gases into the air, including methane, which is 25 times more potent than carbon dioxide.
A lot of fuel energy is used in getting waste from processing facilities to landfill facilities, with some of it ending up on public roads in the process, creating concern and creating sizeable clean-up costs.
The costs of landfill will rise as Australia implements its greenhouse gas reductions targets and the federal government’s National Waste Policy, which outlines the five key principles for waste management, including:
- Avoid waste
- Improve resource recovery
- Increase use of recycled material and build demand and markets for recycled products
- Better manage material flows to benefit human health, the environment and the economy
- Improve information to support innovation, guide investment and enable informed consumer decisions.
According to Michael Bambridge, environmental engineer and wastewater treatment specialist, landfills will become scarcer and more expensive, leading to food processors focusing on waste prevention instead of finding a cure.
Bambridge’s company, CST Wastewater Solutions, has installed various wastewater treatment plants in Australasia, including for leading food and beverage companies such as McCain, Simplot and Golden Circle plus major NZ fruit and vegetable processors and multiple breweries, meat processors, dairy organisations, and municipal WWTPs in Australia and New Zealand.
Frontline components of WWTPs — including more efficient screening and dewatering — are fundamental to efficiently extracting waste and ensuring solids output is delivered in a cleaner and drier state, making it more suitable for composting.
Technologies already employed by leading processors range from better screening and waste extraction and dewatering technology through to anaerobic digestion of organic streams in wastewater to produce biogas to replace fossil fuels.
“It just makes sense in both an environmental and businesses sense — sodden, hazardous waste can cost $150 a tonne to transport to landfills — and landfills themselves are an increasingly expensive and scarce resource. Some Australasian councils are already warning that their landfill facilities will be full before the end of this decade, and there is strong community opposition to opening new ones,” Bambridge said.
CST Wastewater Solutions invested in the local production of its range of rotary drum screens which, with high-performance dewatering, reduce the volumes of solids to be transported and placed in landfill.
The rotary drum screens are now being manufactured in Sydney, increasing quality and supply to Australasia and South Asia.
Locally engineered screens, built for widely varying local conditions, withstand shock loads and larger solids that most other screens using lighter mesh construction cannot — and which may cause them to fail prematurely in peak load conditions, such as floods or spills often encountered in Australasia.
More efficient drum screening technology — featuring a 0.5 mm rotary screen, complete with compactor — was used by a subsidiary of Kraft Heinz to replace the previous plant. In service, this installation has allowed improved and greater removal of solids from the wastewater, with considerably better solids capture. The compact system also permitted removal of a tall existing structure and hoppers, making solids handling more accessible for the plant operator, improving operational efficiency and enhancing OH&S benefits by reducing solids handling.
Examples of engineering features contributing to maximum reliable service life include all-stainless construction, including being fully enclosed for OH&S odour and aerosol control.
Typical industries to use the Rotary Drum Screen include general food processing, beverages, slaughterhouses and abattoirs, tanneries, pulp and paper mills, textile plants, plastic manufacturers and many more industries. Municipal treatment plants also use the screens for fine screening of raw sewage, pre-MBR (membrane bioreactor) screening and sludge thickening for easier handling, transport and disposal.
The screen and compactor technology — which is a first line of defence in preventing downstream process issues, overflows and bypassing to the natural environment — is integral not only to processing operations, but also to the sustainability of livestock industries sharing valuable water resources with nearby communities and wishing to maintain their social licence to operate.
Another clean, green waste management technology introduced to the Australasian market is the KDS sludge dewatering technology that reduces waste volume by up to 90%.
The multi-roller system eliminates processing spillages by producing a drier waste that is more easily transported and recycled. It cuts landfill needs while reducing transport costs and helps prevent any potential spillages onto public roads during transport.
It is engineered to overcome the limitations of technologies such as screw presses, belt presses and centrifuges typically used to treat sludge. It uses very little power and no water for washing.
KDS applications also include thickening and dewatering of Dissolved Air Flotation (DAF) sludge; the KDS captures solids of 95–99% sludge at a dryness of 15–20%. Waste activated sludges are typically 15–18% dryness.
Used on fruit such as apples and pears, the technology dewaters wet, sloppy screened waste, reducing waste volumes by up to 90%.
“It transforms wet waste to a much drier product that is easier to handle, resulting in a more hygienic and cleaner product to transport for recycling to stockfeed and composting,” Bambridge said.
The KDS typically handles 6 m3 (approx. 100–150 kg) per hour of watery waste containing leaves, twigs and unsuitable fruit. The output is transformed into waste for disposal or stock food that is cleaner and healthier to handle.
“Reducing waste volume by up to 90% radically reduces transport costs and helps prevent any potential spillages onto public roads during transport. Both issues are very important, with rising specialised waste disposal transport costs and with local communities and councils very mindful of how companies treat waste,” Bambridge said.
The fruit processor uses the KDS technology to handle a highly variable quality and volume.
The in-channel rotary drum screening technology is built to be both robust and adaptable. Its whole-of-lifespan value is a mature engineering approach in meeting and continuing to meet users’ tasks that vary from place to place, day-to-day and week-to-week as loads on the system change, according to Bambridge.
“We have plenty of screens installed in the industrial space which have been going for more than 25 years with minimal operational costs,” he said.
It builds greater environmental protection, which is something all food and beverage processors must account for as Australasia moves to protect its reputation as a clean-green producer.
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