## 1 Introduction  
The Australian red meat processing (RMP) industry is both energy and resource intensive. Water consumption averages at 9.4 m\({}^{3}\) of fresh water per tonne of hot standard carcass weight (t HSCW) produced, while energy consumption averages 4108 MJ+ HSCW\({}^{-1}\)[1]. From the 7.7 million cattle processed in 2019 [2], this equates to an industry-wide production of 2.2 Mt of carcass weight [3] and a subsequent consumption of 20.68 million m\({}^{3}\) of fresh water and 9038 TJ of energy [1]. As these resources are a significant cost to processors, efforts are being taken by the industry to reduce both water and energy consumption. Likewise, RMP facilities also generate large quantities of waste which can be divided into solid and liquid wastes. Regarding solid waste, the average rate of production was 11.3 kg-t HSCW\({}^{-1}\) for an industry total of 24,860 t sent to landfill in 2019 [1]. Simultaneously, the average rate of wastewater production was 8.7 m\({}^{3}\)-t HSCW\({}^{-1}\) for an industry total of 19.14 million m\({}^{3}\) in 2019 [2, 4]. This wastewater is high-strength with both a high chemical oxygen demand (COD) and a high fat, oil and grease (FOG) content (Table 1) and requires treatment prior to disposal. The greenhouse gas emissions averaged at 432 kg of carbon dioxide equivalent emissions (CO\({}_{2}\)-e) per t HSCW produced, resulting in an industry-wide contribution of 1,330,000 t CO\({}_{2}\)-e in 2018 [5]. Australian RMP facilities have been proactive in introducing engineering solutions to minimise both resource consumption and waste generation. The eco-efficiency manual for meat processing [13] outlines three areas of opportunity:  
* Energy: reduced demand (steam, heat and electricity), improved efficiency (steam), alternative sources (steam, electricity), and improved recovery (heat). * Water: reduction, reuse and alternative sources. * Wastewater: recovery of resources, wastewater treatment and beneficial utilisation. Resource recovery from waste streams is an important consideration both for retaining high-value product and for reducing the impact on down-stream processes such as anaerobic digestion. The eco-efficiency manual [13] identifies and discusses several engineering solutions which have been developed to recover organic solids from the wastewater prior to discharge from the abattoir. Of particular interest is the recovery of FOG. From a resource recovery perspective, tallow produced from rendered fat currently sells for around $750 AUD-t\({}^{-1}\)[14]. Consequently, tallow is a valuable resource to the RMP industry, and the optimisation of fat recovery is a priority. Once fat enters the wastewater system there are several primary wastewater treatment systems which range from simple low-cost screens to more complex and expensive machinery used to recover fat. The eco-efficiency manual for meat processing [13] identifies several of these technologies, their costs and indicative capacities for fat recovery. Importantly, many RMP facilities operate screens (Figure 1a), save-alls (Figure 1b) and dissolved air flotation units (Figure 1c) for which the manual indicates fat recovery of 20-90%, 50-85% and 60-90% respectively. However, data collected by [PERSON], [PERSON] and [PERSON] [11] and presented alongside industry data in Table 1 further demonstrated that even with these technologies in place, large amounts of fat can pass through to secondary treatment processes such as anaerobic lagoons (Table 1).