Pushing the boundaries: Wastech Engineering

With high volumes of material and a need to reduce labour costs, NT Recycling Solutions looked to a new way of thinking to build its materials recovery facility. 

Thinking laterally or “outside the box” requires one to break free of current thinking patterns, open one’s mind to new possibilities or distance oneself from traditional logic.

NT Recycling Solutions (NTRS) was faced with a unique set of parameters and required such a way of thinking. Early last year, the City of Darwin went out to tender to send its kerbside recycling materials to a materials recovery facility (MRF) – with NTRS getting involved in the processing through an arrangement with another organisation.

For NTRS, its aim was to develop a high-volume MRF with lower-than-average labour costs, a challenge somewhat impeded by conventional optical sorting technologies.

It was a problem compounded by the high glass content of its MRF’s throughputs. What was vitally important for NTRS was to distinguish between Container Deposit Scheme (CDS) containers and non-CDS containers, including HDPE, PET, aluminium and steel. The company therefore required an intelligent optical sorting line able to sort a variety of materials.

NTRS also had an existing baler and set up at its MRF so it was after a solution that could work within its existing infrastructure and equipment, while ensuring minimal downtime. These factors prompted an innovative approach and the company turned to Wastech Engineering to provide a bespoke solution. 

Dean Caton, General Manager of NTRS, explains that a stringent quality control system was crucial to solving the company’s challenges. 

“Even though we have a CDS in Darwin, we still tend to get a lot of glass in our kerbside recycling bins,” Dean explains. 

Individual containers are sorted into bunkers below the MSS sort system ready for baling.

“The important consideration for us was to make sure that glass was removed at the start of the process as it can be a highly abrasive product.” 

As an expert in concept design and the manufacture of turnkey solutions for materials recovery facilities, Wastech Engineering took on the challenge to help the site reduce its labour costs. 

To work within NTRS’ requirements, Wastech designed and developed an optical sorting system in conjunction with US-based company MSS. Wastech engineers visited the site last year around April to ascertain the plant and componentry size required. Engineers put together 3D CAD designs, mapped traffic flow on the site and worked around NTRS productivity. 

According to Neil Bone, Managing Director of Wastech Engineering, conventional optical sorters can be costly and often require multiple machines for a variety of materials.

“With low throughputs and a high quantity of containers, NTRS was looking to keep its costs down. We submitted that to MSS and they provided us with a technology that is usually used at the end of the MRF cycle on residuals as a last chance of finding materials that the system had missed,” Neil says.

He says the Wastech team had to think outside the square in discovering the MSS technology, as NTRS was not a greenfield site. Working among people and traffic was a challenge, so as to avoid any occupational health and safety issues and ensure easy access. 

Dean says the Wastech team pushed the boundaries and went above and beyond, increasing the incline rate on the conveyor in order to ensure the systems fitted the plant design. 

He says that Wastech designed an optical sorting system able to handle 10 different types of materials, which he says is unique. The sorting was designed to be conducted across 10 bunkers, with optional screening across three quality control stations if required. 

“Wastech’s MSS optical sorting system has the intelligence to tell containers apart depending on size and density for 95 per cent of CDS materials, as well as a quality control station which limits our manual sorting to only one person,” Dean explains.  

“We were working within a relatively tight space and the system fitted in well with other componentry.” 

Dean says the optical sorting system uses machine learning to characterise the material type before being shot with compressed air and sent through to final bunkers to be baled and onsold. 

“We have an additional quality control point for the material once it is out of the bunker and before it is baled to ensure any unwanted materials are removed,” Dean says. 

He adds that NTRS also required a five-tonne-an-hour machine and 4500-tonne-a-year processing capacity, which he says can even be achieved with the machine running at about 50 to 60 per cent capacity. To fulfil these requirements, it was particularly important NTRS was operational the entire time, with Wastech completing the set-up in roughly eight to 10 weeks with no downtime.

He says Wastech also provided a high level of after-sales support, returning a month later to assist with fine-tuning and modifications to maximise efficiency. 

“We had a list of 35 things to consider for the plant and to their credit they designed, changed and modified the gear.”

With a dedicated after-sales customer service support team of around 40, Wastech is there to ensure any problems are solved in a timely manner.

“Wastech also has access to MSS online system so they can jump online and look at what is going on should we have any issues,” Dean says.