In an era when national quarrying is no longer city-based, even during the infrastructure boom, the first 60 hectares (150 acres) of quarries within 30 kilometers of Australia’s major capital cities are rare.

The Repurpose It site on Epping Cooper Street in Melbourne’s northern suburbs is part of a once-historic quarry covering an area of ​​526 hectares (1,300 acres), including the suburbs of Epping, Wollert and South Morang, and has basalt reserves.

The depleted quarry was converted into a landfill, and the ownership of the land was returned to the county authority in the Whittlesea Council. In 2016, the City Council signed an ambitious plan-Quarry Hills Precinct Structure-to transform 280 hectares into parks, businesses and housing, of which 150 hectares are considered "net developable area." In the long run, the area can accommodate up to 2,300 houses and 6,600 people.

In preparation for this transition, the Victorian Government has designated the Cooper Street area as a resource recovery center. Reusing it is considered a valuable part of this center. It operates on a 60-hectare old quarry, which has never been converted into a landfill, but is mainly buffered by the old landfill, giving it 1.2 kilometers of breathing space from the nearest residence.

The company has leased half of the site for a period of 20 years-cleaning and filling operations to repair old pits, while developing final products for use in excavating spoil, construction and demolition (C&D) materials, compost and other organic materials for infrastructure projects Material. An important part of its operation includes the commissioning of the first C&D garbage washing plant that is believed to be Australia's first dedicated to the production of artificial sand and water-washed aggregates.

Reuse It is a relatively new player in the Victorian recycled aggregate market and has been in operation for less than three years. In March of this year, infrastructure and engineering services giant Downer purchased a 50% stake in the company.

George Hatzimanolis, CEO and director of Repurpose It, started this business after being fascinated by the reuse of building materials and reducing the construction industry’s reliance on extractive resources.

“I have worked in the road construction and maintenance industry for 15 years, mainly in the pavement paving business with Downer,” Hatzimanolis told Quarry. "About eight years ago, when I started to use alternative materials to extract resources, I became enthusiastic about all recycling and tried to replace aggregates in sand and asphalt with residues from recycling or other waste products. I also introduced Some materials, such as toner recovered from print cartridges, are used as polymers, waste glass is used as a substitute for sand, rubber-modified asphalt, industrial waste oil, recycled asphalt pavement. I am really passionate about sustainable development for this reason ."

Repurpose It began operations in 2017, providing services and expertise in multiple transfer stations, waste management consulting, construction materials and soil improvement, organic and green waste treatment, waste transportation and collection, and important waste resource operations.

It applies to six main types of materials: green and organic; civil construction and infrastructure waste; excavation and demolition waste; municipal solid waste; solid inert waste; and drilling and drainage waste.

“Our business is designed around the excavation of spoils, especially building-type abandoned spoils," Hatzimanolis said. "Anything generated from road or rail reserves is the type of waste stream we process and process-green or organic waste, soil, excavated rock or other forms of excavated spoil."

The company is headquartered in Epping and also executes contract work for local councils, including Manninghamshire, Brimbank and Banyul. Reuse It also operates under contract for West Melbourne's Citywide Waste Management Company. In 2016, Citywide opened Australia's first street sweeping and tunnel cleaning recycling plant, which can process up to 22,000 tons of street sweeping waste streams each year, including gravel, plastic, paper, cardboard, wood, garbage and glass. These materials have been reused in standard road maintenance projects.

Reusing it has also cooperated with numerous civil construction companies, including Downer, John Holland, Eastern Plant Hire and Transurban, in projects across Victoria, such as Western Distributor, subway tunnels and the Victorian government's level crossing demolition project. A large amount of excavation spoil from these railway and highway projects is inevitably transported to Repurpose It for processing.

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Hatzimanolis said that the reuse of it was “a material that other quarrying companies or crushing operations would reject”. We are concerned with materials that are excessively contaminated, soil and clay content are too high, or other inert or contaminated waste levels. We see ourselves as a service provider for materials that are not normally processed by quarries, and we have invested in technology to recover resources from them to ensure that we optimize what can be recycled and reduce the industry’s reliance on extractive resources.

"The quarry is under tremendous pressure. Obviously, the type of material we recycle will relieve some of the pressure during the massive infrastructure boom. We are located in the north of Melbourne, only 28 kilometers from the Central Business District, which means we can help The client provides an effective place to dispose of their spoil-from which we collect materials that can be recycled into sand, soil and aggregates.

"Our washing plant aims to recover sand and aggregate particles from excavated soil, so by volume, this is the main waste we deal with."

The $8.5 million fixed washing plant covers an area of ​​1,000 square meters and is manufactured by CDE Global. It includes an Aggmax 250, multiple Infinity H2-60 horizontal screens, a centrifuge for sludge dewatering, and an AquaCycle thickening tank.

"This is abrasion by Aggmax's high-pressure water, another set of washing screens clean the sand, and then water treatment," Hatzimanolis said. "Depending on the feed, the washing plant itself can handle anywhere between 150 and 250 tons per hour. It has an annual output of 500,000 tons."

Hatzimanolis explained that the decision to invest in the construction of a waste washing plant was made on the basis of extensive research at home and abroad. Repurposed by establishing the Citywide washing plant, it also established a previous relationship with CDE Enviro, the environmental arm of CDE Global's business. This played an important role in the company's decision to purchase CDE washing equipment for its Epping business.

"We studied the seven or eight factories CDE built in the UK and how to improve and optimize the design based on people's learning and experience," he said. "We saw some nuances in some factories, some operators introduced designs for their specific waste streams, and what we did was make the most of what we saw in the settings.

"We want to deal with various wastes, some heavily polluted wastes, some inert wastes, in which organic matter and other materials will be highly polluted, and materials with very high fine powder content. We also know that there are opportunities for hydraulic excavation of the space around the drilling mud , Because it is also possible to recover sand and aggregate parts from this material.

"So when we came up with our design, it did make full use of the best CDE factory we have seen, and adopted some wisdom in the factory layout on our site, such as excavating the range of waste types, including hydraulic excavation. We need to build capacity for waste, especially to be able to deal with some contaminated waste."

At the time of writing, the washing plant has been in operation for nearly four months, and Hatzimanolis said he is satisfied with the way it operates.

"This is a complex plant with many moving parts, and we are dealing with a wide variety of waste streams-unlike a quarry working in a specific reserve, or a crushing business with two or three products of waste streams.

"We are dealing with a wide range of waste, so we may put quite a lot of requirements on the capacity of the factory. This is constantly in need of improvement. However, we provide a lot of resources for the business from a technical point of view, because when you are in various waste This is exactly what you need when running complex factories in logistics.

"Washing plants have very consistent screening quality on particle sizes of 0-2 mm, 2-5 mm, 5 mm, 10 mm, 14 mm, 20 mm, and 50 mm. Therefore, we can obtain high-quality screening materials and can provide And meet the required particle size distribution of our specifications, without further processing."

Artificial sand produced by separating materials from particles below 150 mm is being reused for concrete, asphalt, sand and aggregate replacement applications, and covered in landfills. Even plant residues are still useful.

"The percentage of recyclables depends on the feed material. Obviously, if we are cleaning things with high clay or silt content, then we will get more residue from the thickening tank. According to the way the material is classified, it still has As a construction application of structural filling, not as a sand aggregate. So there are applications of structural filling. We have some customers who have been purchasing this product. As part of the quarry restoration, we ourselves also need it.

"Usually, this is a good part, about 75 microns. It is a shovelable material, but it does have good construction applications. We are doing a lot of work and research. Some are cooperating with universities and about other applications. , It can be mixed and value-added to be used as structural filling."

The railway ballast spoil from the Victorian level crossing project is also a challenging cleaning product. Hatzimanolis said: "The ballast produced by the washing process is as good as the ballast that enters." "This is about cleaning materials, so we can test our ballast and make sure it is technically suitable for repeated use, our priority It is to achieve the highest possible value of reuse—preferably back to the railway network as railway ballast.

"Regarding the reuse of ballast, we have received a lot of support and interest from VicTrack, MTM, V-Line, and Yarra Valley Rail. Once it is proven that it meets the specifications, they will now resupply the ballast. If the ballast is partially The quality is variable, so it will disappear in other forms. It can still be used as ballast, but it can be used to transport roads or drainage media instead of returning to the road network."

It can also accept and clean recycled glass from a fraction of 10 mm to 14 mm. The glass comes from other material recycling facilities that collect it as roadside waste and process it into residual glass that is not suitable for glass recycling applications.

The challenge in processing glass powder is to successfully remove surface contaminants, which may include organics, plastics, and non-ferrous materials.

Hatzimanolis said: "It can be very smelly, with bacterial problems, sugar, organic matter, molasses on glass powder." "Our process can clean those glass particles by friction and high-pressure water scrubbing, which means that when it is used as a bedding Or when it is reused by contractors, it is a more user-friendly material. In addition, we are still studying which end products can be designed with cleaner glass parts. What is the best reuse? It can be recycled In glass manufacturing or can we use it to make other building materials?"

In the promotion, Repurpose It emphasized that the washing plant processes 100,000 tons of materials and has a low emission footprint.

It produces 5,000 tons of carbon dioxide per year—and the broader industry produces an average of 22,000 tons of carbon dioxide per year. Hatzimanolis said that the annual reduction of 17,000 tons of carbon emissions is based on several factors.

"The emission footprint depends on the total volume being cleaned, but we have an independent life cycle assessment to quantify our CO2 emissions," he explained.

"On average, for every ton of material transferred from the landfill to our facility and reused sand and aggregate, we can save approximately 168 kg of carbon dioxide.

"Therefore, each ton of 168 kg of carbon dioxide with a capacity of 500,000 tons is approximately 84,000 tons of carbon dioxide, which can be transferred from the atmosphere through our facilities each year. This is a considerable offset against carbon dioxide on the market.

"We looked at the total area, which includes the water part and the electricity part of the factory. In terms of fuel, quarrying can be very energy intensive, and it is clear that transporting these materials from the quarry will have an impact.

"Sand is farther from the market than we are in Epping. Therefore, our emissions footprint really focuses on the entire impact. We see ourselves as a source of urban sand, and we are the closest source of sand to the Melbourne market, only 28 kilometers away from the city. This Provides an opportunity to reduce the use of trucks on the road and reduce carbon dioxide emissions."

In addition to developing more environmentally friendly operations, Repurpose It also actively participates in research and development programs of statutory bodies, non-profit organizations, and universities to improve its final products.

In 2018, the company received funding from the Victorian Department of Sustainable Development to develop a washing plant and also applied for certification of its products through the Green Star process of the Australian Green Building Council.

In addition to cooperating with RMIT to develop clean glass parts that can be reused in glass manufacturing, Repurpose It is also cooperating with Swinburne University of Technology to study the capabilities of its recycled aggregate and sand in concrete applications. Repurposing it also benefits from an on-site laboratory approved by the National Association of Testing Agencies and a large R&D facility owned by Downer in nearby Somerton. Hatzimanolis said the company is cooperating with standards bodies such as VicRoads, the Australian Road Research Council, the Cement Industry Federation and the Australian Infrastructure Sustainability Council to update the acceptance specifications for recyclable materials.

"Many organizations are moving in the right direction, especially VicRoads. In the past few years, we have indeed seen a change in their mentality in promoting the use and procurement of recycled materials, which will undoubtedly help people like us. Of companies make investments.

“Some water departments still have a lot of work to do. Their specifications on bedding are outdated. There are some specifications that involve purchasing from primitive quarries, and we think these specifications are outdated.

"We are attracting audiences and we are starting to get attention, but like most large government agencies, changes do not always happen with the development of technology. So this is a challenge for the industry, not just a repurpose. . We need others to lobby with us to move things forward."

Hatzimanolis is optimistic about the future of Repurpose It and its position in the recycled aggregate market.

He stated that the company “has set ambitious growth targets in other markets in Victoria and other regions”, and he believes that the long-term growth of the business will depend on “reflecting the investments we have made in the market”.

"The premise of our business is to invest in best-practice technologies to turn waste that is normally unprocessable into resources, and these are the values ​​that drive us forward," Hatzimanolis said.

He predicted that the company will continue to participate in a series of partnerships. He does not rule out cooperating with other recycling groups with "suitable business fit", and seeking to diversify into the quarrying business of the recycled aggregate/waste resource market.

“Many quarries have residual waste, scalp and other materials that cannot be effectively processed by traditional dry processing applications,” Hatzimanolis said.

"We have talked with some quarries about how our technology can be applied to them. We see ourselves as a complement to the quarrying industry because we believe that our materials can relieve some of their pressure.

"So we are absolutely open to meaningful partnerships."

The first purpose-built wet processing plant

CDE Global provided equipment for Repurpose It's C&D material washing plant. It consists of an Aggmax 250, several Infinity H2-60 horizontal screening machines, a centrifuge for sludge dewatering and an AquaCycle thickening tank.

"This is a custom design," said Dan Webber, CDE Global's Australia regional manager. "We brought George [Hatzmanolis] and his team to various CDE waste recycling plants, so they know the situation very well and know what they want and what they don't want.

"Speaking of which, George is very confident that our expert engineers and design team can develop a first-class factory. The key requirement is to design a powerful process that can produce countless products, and an efficient tailings management system."

Webber agreed with the suggestion that the Repurpose It plant is indeed the "first" of the 40 CDE Global washing plants operating in Australia.

"This is our first dedicated C&D waste recycling plant in Australia," he said. "Globally, this is now a very important part of our business. CDE has installed more than 65 C&D factories around the world and now has a dedicated "Reco" business unit so that we can further consolidate our success. The construction, demolition, and excavation recycling industries develop new solutions."

Weber added that the Repurpose It plant is also “the first wet processing plant in Australia dedicated to recycling C&D waste. Other waste treatment plants may dry screen materials or manually select contaminants, but so far have not used wet processing plants. Law processing.

“The biggest difference between the cleaning plant for raw materials and C&D waste is the inconsistent feed,” he added. "The feed is usually very dirty-high clay content and oversized-which means we need to carefully choose the most effective equipment to process the feed.

"We usually use some of our high-tech washing equipment-such as the AggMax wood washer-which can clean the aggregate and release the sand in the clay. Another big difference is that the C&D waste recycling plant is almost always in the back A dry tailings system is installed at the end. In this case, Repurpose It requires CDE to integrate our decanter centrifuge system."

Repurpose It’s feedback on the initial performance of the plant that started operations in March was positive. "Repurposed and handled it very well during commissioning," Weber said. "They really want to learn how to operate and get the most out of the factory. They give it all-some very challenging materials, a lot of clay and oversize-and it has stood up very well."

Weber said that CDE Global may again cooperate with Repurpose It and Downer Group. "I think that after our success with Repurpose It, coupled with the great factory that our sister company CDEnviro delivered to Sydney Downer to recycle road cleaning materials, we started to build a good relationship."

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