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Sensor-Based Sorting Technology – Maximising Recovery From Msw

Tasos Bereketidis, Regional Director Emerging Markets at TOMRA Sorting Solutions, takes a closer look at the treatment of municipal solid waste in Saudi Arabia and examines the role that sensor-based sorting technology could play in enabling the Kingdom to maximise recovery from MSW.

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October 28 2018
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Over the past few decades, Saudi Arabia has witnessed rapid population growth and urbanisation, which has led to a steady increase in the generation of residual black bag waste – also referred to as municipal solid waste (MSW). With a population of around 29 million, the country currently generates more than 15 million tons of solid waste per year, of which only 10-15% is currently recycled. Saudi Arabia’s infrastructure for the recovery of valuable materials from MSW is still at an embryonic stage and there is a lack of largescale and automated MSW sorting plants.


Historically, the country has relied almost entirely on landfill for its MSW, but landfill isn’t a practical, commercially-viable or sustainable long-term solution. The past few years have seen growing recognition – and acceptance – of the need to develop a more sustainable and integrated approach to the nation’s MSW in order to reduce reliance on landfill and maximise recovery of valuable recyclables from this waste stream. The Saudi Government is now making a concerted effort to improve recycling and waste disposal activities, and investment in new MSW plants and upgrades of existing facilities is starting to take place across both the public and private sectors.

Value in MSW

MSW contains a variety of valuable, recyclable materials, including mixed paper, PET, HDPE/PP, LDPE film, metals and glass. In Saudi Arabia, the MSW waste stream comprises organic waste (37.5 percent), paper waste (28.5 percent), plastic waste (5.2 percent), metal waste (8 percent), glass (4.6 percent), textiles (6.4 percent) and wood (2.2 percent)*. With increasing demand for these recovered materials, in particular PET, from end customers within Saudi Arabia and internationally, there are strong commercial reasons for capturing these materials for resale rather than sending them to landfill.

However, at present, Saudi Arabia’s MSW reprocessing capability is almost entirely limited to manual sorting plants, making it impossible to recover the quantity or quality of secondary materials required by end markets. It is only by taking advantage of the recent advances in sensorbased sorting technology that plant operators will be able to achieve high recovery and purity rates of recoverable fractions from this waste stream. Using a combination of sensor-based sorting technology, equipment can be programmed to identify and separate each individual fraction, extracting maximum value from MSW, diverting material from landfill and increasing recovery of materials for re-sale. So, how does it work?

After upfront mechanical treatment has taken place, TOMRA’s AUTOSORT units use the latest advances in sensor-based sorting, including near infrared (NIR) and visual spectrometers (VIS) to accurately and quickly recognise and separate different materials according to their material type and colour, extracting high-purity end fractions. NIR technology is used for sorting materials and the VIS sensors for sorting colours. Our AUTOSORT unit can achieve high purity rates recyclables, with recovery yields of over 92 per cent – compared to the 50 per cent recovery rate achieved by manual or semi-automated techniques.

These units are already installed in a significant number of plastic recycling facilities throughout Saudi Arabia and are consistently achieving purity rates of 94 per cent when targeting PET, a much sought after resource both in Saudi Arabia and further afield. To further strengthen the capabilities of our AUTOSORT unit, we recently launched a unique laser-based solution that enables processors to achieve higher final product purity levels than ever before. When used in combination with our AUTOSORT system, TOMRA Sorting’s new Laser Object Detection (LOD) system features laser technology that sorts based on the feed material’s spectral and spatial characteristics, enabling the detection of material such as black plastic, rubber, glass, and other waste items that near infrared technology (NIR) is incapable of identifying.

As a result, final product purity is increased by as much as 4 per cent. With plastics being one of the major components of MSW in Saudi Arabia, plant operators will be interested to hear that we have also recently introduced a new technology called TOMRA SHARP EYE. This technology makes it possible to separate singlelayer PET trays from PET bottles and enhances the previous capability of our AUTOSORT machine to separate multi-layer trays. This breakthrough is commercially significant because small, but critical differences in the chemical properties of PET food trays and PET bottles mean that they have to be separated for equivalent-product recycling. In addition, intelligent computing technology embedded in TOMRA systems enables seamless analysis of sorted products, making future plants even smarter.

Looking to the future

While the use of sensor-based sorting technology in MSW recycling is very much still in its infancy in Saudi Arabia, it is achieving great results in upgrading plastics at plastic recycling facilities nationwide, so we are actively encouraging MSW plant operators to visit these reference plants to see at first hand the technology in action and the results being achieved. I believe sensor-based sorting technology has a vital role to play as Saudi Arabia moves towards a more established infrastructure for MSW. With sensor-based sorting in place, plant operators can be guaranteed of achieving the quantity and quality of recovered materials they require, manual picking is virtually eliminated so labour costs are kept to a minimum, landfill reliance reduces dramatically and profitable end markets can be exploited.

*Source: The General Authority of Meteorology and Environmental Protection (GAMEP)/ Ministry of Municipal and Rural Affairs