Features, Waste Management In Action

STEINERT technology allows composters to improve product

STEINERT’s Kurt Palmer explains how the company’s UniSort Black technology will allow composters to improve their product, with potential to sell it to new markets.

Diverting organics from landfill is increasingly becoming a higher priority for governments and councils across Australia.

The Victorian Government in 2017 highlighted it was diverting more than half a million tonnes of food and garden waste away from Melbourne’s landfill annually, while the NSW’s Waste Less, Recycle More Organics Infrastructure grant program will fund $55.67 million in projects over its nine-year life span. The National Waste Report 2016 shows 51 per cent of organics was recovered in 2014-15 across the country, indicating there may still be some work to be done in this area.

It’s exactly why STEINERT, a world leader in sensor-based sorting, has developed a sorting technology to help councils, materials recovery facilities, paper plants and composters keep more organics out of landfill. STEINERT’s UniSort Black technology hit the market in late 2017 and the company’s Business Development Manager – Environmental, Kurt Palmer, says companies in Australia are eagerly queuing up to test the machine locally. What sets STEINERT as a company apart from others, Kurt says, is its ability to offer both magnetic and sensor-based sorting technology.

He says the diverse sorting technology is suited to both small and large composting operations. Despite the best efforts of households in putting their organics in the correct bins, Kurt says the lack of sorting technologies has continually put commercial composting operations at risk due to foreign particles. It means that the markets for compost have previously been limited to remediation works and industrial applications. Kurt says he hopes UniSort Black will open the market up to composters seeking to sell their products to retail outlets. It’s all due to the technology’s capacity to rectify mistakes made by residents at the kerbside.

“Human beings will always want to take the easiest route possible and so there will always be contamination, particularly as we see more councils roll out food and garden organics collections across Australia,” Kurt says.

“Innocent mistakes can be made by households. For example, when you are disposing of garden waste there may be bits and pieces within that waste that fails to catch the resident’s attention.”

Kurt says the UniSort Black serves as a supplementary quality assurance technology for organics processing facilities. Depending on the organics waste stream and kerbside service, household bins can contain foreign particle contaminants such as glass, plastics and metals. Not only this, Kurt adds that a compost that isn’t aesthetically pleasing also frequently fails to appeal to the retail sector.

He says STEINERT has ensured the technology it distributes to the composting market adheres to rigorous standards. According to the German standards for composting, RAL-G2-251, only 25 square centimetres of foreign particles are permitted per litre of fresh substance in fresh and finished compost.

Kurt explains that after the raw materials have undergone initial composting, magnets above the belt remove any ferrous metal components prior to reaching the UniSort Black.

The next phase of pre-processing allows sieves and wind sifters to pre-condition the material for processing in the UniSort Black. Sieves remove the fine material, such as dirt, and wind sifters remove the light fraction of objects such as plastic films.

“Essentially, these wind sifters separate the heavy fractions from the light fractions. The UniSort Black processes the heavy fraction of organics, as that’s where the majority of contaminants are,” Kurt says.

Once this process is finished, conveyor belts move the material to the UniSort Black, which separates out all plastics, including all dark-coloured and black plastics, as well as any remaining foils and metals. Kurt says the technology removes more than 98 per cent of foreign particles. At this stage, the technology can also sort and remove any broken glass, stones and ceramics.

“The UniSort Black sorting system consists of a near infrared sensor, which allows us to detect these potential contaminants,” Kurt says.

Kurt says particles reflect light within a certain range and, for these reasons the system is able to identify contaminants within a near-infrared electromagnetic spectrum of 750-950 nanometres. The electromagnetic spectrum is a collective term to refer to the entire range of frequencies of electromagnetic radiation. Near-infrared can identify unknown substances with a spectrum of frequencies, which can be measured in either reflection or transmission. Nanometres is the unit of measurement for the wavelength of electromagnetic radiation.

STEINERT’s Kurt Palmer says the lack of sorting technologies puts commercial composters at risk due to foreign particles.

“We can identify organic material, we can identify plastics by type, in addition to all sorts of other materials,” he says.

“The beauty of the technology is we can also identify unidentifiable objects. If something doesn’t reflect that nanometre spectrum, we don’t see it, but we know something is there. Because organics is within that range, we can reject anything else because we know it can’t be organics. This applies to materials such as rubber and black plastic.”

Kurt says the use of hyper spectral imaging technology enables UniSort Black to recognise multiple types of material simultaneously, setting it apart from other technology. He says the hyper spectral imaging camera within the UniSort Black is able to detect more than 27 million particles per second when placed on the conveyor belt.

“The reason that’s important is it gives us a lot more information about the material that’s on the belt and the more information you have, the better sorting decisions you can make – such as whether you want to keep or remove the materials.

“Compared to other technologies, hyper spectral imaging technology is the difference between an old 20th century camera and an iPhone camera.”

Following this process, the material is ready to undergo final composting and be sold to retailers.

Depending on the application, the technology can process organics at a throughput rate of six to 10 tonnes per working hour at a width of 2.8 metres. The grain sizes it can process at any one time are adjustable and range from about 10 to 70 millimetres and from 70 to 350 millimetres.

So what does the future hold for the technology in 2018?

Kurt says the company will be speaking with the Australian Organics Recycling Association to ascertain whether there will be any local standards established for foreign particle size requirements. As the organics processing sector continues to grow, STEINERT will continue to offer its technology to emerging markets.

“We want to give composters the flexibility to expand their operations. The retail market has a lot more value and we want organics processors to be able to produce bagged compost which is almost identical to virgin materials.”   

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