Recent changes related to antimicrobial intervention technologies and reduction in product loss have affected cattle slaughterhouse wastewater streams. In this study, wastewater samples were collected from two cattle slaughterhouses located in the Midwest of the United States, focusing on the overall wastewater, antimicrobial interventions, and viscera and offal processing. The wastewater concentrations were affected by the water use, dilution, processes, and wastewater pretreatment that occurs within the slaughterhouse. Even though there were differences in the wastewater concentrations, the overall wastewater loads for both slaughterhouses were similar. The overall mean total solids (TS), volatile solids (VS), 5-day biological chemical demand (BOD5), and chemical oxygen demand (COD) wastewater loads for the two slaughterhouses were 16.8, 10.0, 4.7, and 12.5 kg/1000 kg live weight killed, respectively. Wastewater streams from antimicrobial interventions have low pH and are potential sources of shock loadings. Wastewater from viscera and offal processing has high nutrient concentration; therefore, any improvement in this process could enhance the sustainability the industry.
Data regarding the water and energy usage of current antimicrobial interventions in beef packing plants is scarce. The objective of this study was to collect representative water and energy usage data in a beef packing plant, with emphasis on antimicrobial interventions, to provide baseline data for comparison of new intervention technologies developed by researchers. Permanent and portable water flow meters were installed on the plant's plumbing system to collect water flow data from March 2014 to March 2015. A local utility company was hired to meter electricity at the different subsystems using portable data loggers. The natural gas used in each subsystem was estimated by the amount of steam required to heat the water to the desired temperature and assuming the boiler efficiency as 82%, as estimated by the plant personnel. All data was normalized per 1000 kg live body weight (1000 kg LBW). The overall plant-wide water usage was 2968 L/1000 kg LBW (355 gal/1000 lb LBW). The antimicrobial interventions used 15.7% of the total water usage while viscera and byproducts processing, and overnight cleaning water accounted for 19% and 39% of the total water usage, respectively. The water usage was 100, 16, 253, and 97 L/1000 kg LBW for the pre-evisceration wash, organic acid spraying, carcass wash, and thermal pasteurization, respectively. The total metered electrical energy was 110.5 MJ/1000 kg LBW, over 96% of which was used by the plant's cooling and hydraulic systems. The overall plant-wide natural gas usage was 512.6 MJ/1000 kg LBW, 11.6% of which was used by antimicrobial interventions for water heating. The viscera and byproducts processing, overnight cleaning, and other usage and losses, accounted for 11.7%, 36.1%, and 40.6% of the total natural gas, respectively.
Food processing industries consume intensive water and energy to produce food products. However, their water and energy data are scarce and require for good measurement approaches. This study presents data collection and analysis of process‐level water and energy use in a large‐size U.S. beef packing plant through a combined use of portable and in‐line meters and theoretical calculations. The kill floor and plant cleaning are the primary water users, accounting for 28.7 and 24.0%, respectively. The refrigeration compressor system is the largest user of electricity, consuming 24.5% of plant‐wide electricity. Heating of water for plant cleaning and food safety purposes is the largest thermal energy use in summer (81%) and second‐largest in winter (49.7%), with unit heating values of 625 and 666 MJ/ton live cattle weight in the summer and winter, respectively. Twice as much thermal energy is used in the winter than summer due to space heating requirements. A regression analysis found that as outdoor temperatures increased, a slight water use increase and larger energy use decrease were observed.
Practical applications
Currently available data on water and energy use in the U.S. beef packing industry are scarce, thus limiting the ability to develop new water and energy efficient technologies and policies based on an understanding of the current baseline operations. The current study conducts a detailed assessment of water and energy use at process level to enhance the understanding of the food‐energy‐water nexus in the beef processing industry, where limited data are available. Engineers can apply this case study as an example to share with their clients seeking to collect and analyze data with the goal of identifying water and energy conservation approaches. These results will inform beef processing researchers as they design novel technologies with that may result in improved water and energy efficiencies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.