###### Abstract  
The pet food industry faces significant sustainability challenges, including reducing energy consumption, lowering emissions, and adopting circular economy practices. This study aimed to assess and propose energy efficiency measures to enhance sustainability within the sector. The research evaluated the use of unapproved food as biomass for boiler combustion. It analyzed its chemical composition, energy impact, and emissions of volatile organic compounds (VOCs) through TD-GC/MS, as well as the corrosion effects on boiler metals. An energy assessment of the production process and a combustion characterization of the waste were conducted to identify opportunities for improving energy efficiency and sustainability. The results demonstrated that the chemical composition of the waste and other biomass-related parameters were within acceptable economic and environmental ranges. A reduction of 0.015 Mg of CO\({}_{2}\)eq per Mg of produced pet food was achieved. Regarding VOCs, their environmental impact was minimal due to the molecular structure of the compounds. Additionally, the corrosion rate caused by waste incineration was comparable to that of domestic gas in the case of cat food, with a rate of 214.74 mpy, while the dog food yielded 55.42 mpy, which is near that of other types of biomass, such as wood chips and pellets. The use of residual biomass in pet food production is a viable alternative for reducing carbon footprint, promoting a circular economy, and improving the industry's sustainability. circular economy; greenhouse gas (GHG); energetic efficiency; biomass 2020 IEEE/ACM Transactions on Ge  
In Chile, where this study was conducted, several initiatives have emerged as regulatory frameworks to promote the adoption of sustainable industrial practices and reduce the environmental footprint of production processes. Notable examples include the Energy Policy 2050 [3], the Energy Efficiency Law [4] (Law 21.305), and the Framework Law on Waste Management, Extended Producer Responsibility, and Promotion of Recycling [5] (Law 20.920). These regulations have encouraged local industries to intensify their efforts to combat climate change by optimizing resource consumption to satisfy demand while maintaining a controlled or acceptable environmental impact. Additionally, consumer preferences are increasingly shifting toward products with lower carbon footprints [6]. The pet food industry is not exempt from this environmental challenge. It is a rapidly growing sector with significant environmental impacts. In the United States, pets are responsible for 25-30% of the environmental burden associated with animal production, including land, water, fossil fuel, phosphate, and biocide use. Pet consumption also contributes approximately 64 million Mg of CO\({}_{2}\)eq emissions annually [7; 8]. The pet care market has significantly expanded in the country, reaching a value of USD 1.83 billion in 2024, and it is projected to grow to USD 3.25 billion by 2032 [9]. However, this growth also generates a considerable amount of solid waste, including pet food batches that do not meet commercial quality standards and are typically discarded or treated as waste. Moreover, manufacturing processes in the pet food industry are characterized by high energy consumption due to the complexity and intensity of production activities [10]. Electrical energy is extensively used to operate machinery involved in grinding, mixing, extrusion, drying, and packaging [10]. Simultaneously, thermal energy, primarily from natural gas, is essential for cooking, extrusion heating, and drying processes that require precise temperature control to ensure product quality and food safety [11]. [PERSON] et al. [12] evaluated the technological feasibility of transitioning from fossil fuels to renewable alternatives for fueling boilers in the wet pet food processing industry, aiming to reduce emissions. In that study, the specific type of biomass used was not analyzed, as the focus was on commercialized and standardized biomass products.