O.C.O Technology has formed a joint venture with Australian construction and demolition materials recycler City Circle Group to develop a plant in Victoria that converts waste-to-energy residues into manufactured construction aggregate. The new business, O.C.O Victoria, plans a multi-million Australian dollar facility built around the British company’s accelerated carbonation process. Its stated annual treatment capacity is up to 150,000 tonnes of air pollution control residues, with an equivalent quantity of aggregate expected to be produced once the project is operational.
City Circle handles construction and demolition materials in Melbourne, while O.C.O brings a treatment process for residues from thermal waste facilities. The partnership combines a prospective source of industrial waste with access to a local construction materials market. O.C.O Victoria was introduced during Waste Expo Australia in Melbourne, but the partners have not specified a site opening date or a more precise investment budget than several million Australian dollars.
Air pollution control residue, usually abbreviated to APCr, is collected when systems remove pollutants from gases produced by energy-from-waste facilities. It is distinct from the larger quantities of bottom ash removed from the combustion chamber. The chemistry and handling requirements of APCr make it a more demanding material to recover. O.C.O’s proposed manufacturing route applies controlled reaction with carbon dioxide to convert appropriate mineral constituents into stable carbonates, providing both a treatment step and a route to a usable product.
Accelerated carbonation draws on reactions that can occur naturally when alkaline mineral materials are exposed to carbon dioxide. By controlling the process, a conversion that would otherwise proceed slowly can be carried out within industrial processing times. O.C.O describes a route in which residues are combined with binders and fillers, carbonated and formed into rounded manufactured limestone aggregate. Process conditions and the formulation determine how consistently the resulting granules meet the specification required for their intended construction application.
Carbonation fixes carbon dioxide into stable carbonate minerals. Mixing and pelletising then turn the treated material into particles that can be graded, transported and incorporated into suitable construction products. Processing consistency depends on the chemistry of incoming residue, the addition of binders and fillers, and control of the reaction and granule formation. Variations in the feedstock would have to be managed through testing and changes to the production recipe.
At the intended maximum throughput, O.C.O Victoria expects roughly one tonne of manufactured aggregate from each tonne of APCr treated. O.C.O also estimates that each tonne of its aggregate can substitute for about 1.4 tonnes of natural aggregate. The ratios describe the company’s proposed process and substitution performance, with actual sales dependent on the amount processed and the construction uses for which the product is accepted. Reliable residue deliveries and outlets for finished material will determine how closely the plant approaches its stated production capacity.
Construction customers will need consistent grading, density, strength, water absorption and environmental performance before specifying manufactured aggregate in particular products. Those requirements connect the chemical treatment operation to conventional mineral-product quality assurance. Material must remain sufficiently consistent for receiving plants to batch and handle it predictably, so testing of the granules becomes part of the manufacturing route rather than an optional final check.
O.C.O already operates manufacturing facilities in the UK and continental Europe, and has technology partnerships in Japan and the United States. In May, its Biscay Eco Aggregates partnership began manufacturing at the Port of Bilbao in Spain in a project involving Petronor. The Spanish investment was reported at €20 million, with O.C.O holding a minority stake. The Victorian venture extends that international model into a market developing its own energy-from-waste sector and demanding alternative aggregate supplies.
City Circle’s established construction and demolition recycling operations could provide access to material handling and customer channels around Melbourne. Aggregate is bulky and costly to transport relative to its unit value, so the location of waste suppliers, processing operations and end users will influence the venture’s cost base. Contracts for residue supply, product acceptance and distribution will also determine whether the planned plant can maintain regular production runs.
Before commissioning, the plant will need the necessary approvals for receiving and processing APCr, followed by equipment installation, trial production and validation of the resulting aggregate. Treatment capacity is a design limit, while delivered annual output depends on utilisation, maintenance, waste availability and product demand. Establishing consistent operation will also require the project partners to demonstrate the process under the range of residue conditions supplied by Australian facilities.
O.C.O Victoria brings together the economics of residue treatment and the manufacture of a saleable construction material. The treatment process will require reliable industrial inputs, while aggregate revenue depends on meeting customer specifications and securing repeat orders. The partners have not published their revenue arrangements or a firm completion schedule, so commercial output will follow both technical commissioning and the development of local supply contracts.
The next steps are permitting, construction and commissioning of the Victorian plant, followed by customer qualification of the manufactured aggregate. The eventual production rate will depend on waste deliveries, process stability and demand from construction customers. Successful operation would give Australian energy-from-waste operators a manufacturing outlet for residues that would otherwise require disposal.
