Food Sector—Pollution Prevention (P2) Opportunities
The food manufacturing industry includes facilities that produce foods or food ingredients. The industry covers a range of industrial processes, varying from preparation (e.g. slaughtering, milling) to processing (e.g. cooking, freezing, fermenting) to packaging. As classified under North American Industry Classification System (NAICS 311), the Food Manufacturing sector, consists of nine subsectors:
- Animal Food Manufacturing
- Grain and Oilseed Milling
- Sugar and Confectionery Product Manufacturing
- Fruit and Vegetable Preserving and Manufacturing
- Dairy Product Manufacturing
- Animal Slaughtering and Processing (Meats)
- Seafood Product Preparation and Packaging
- Bakeries and Tortilla Manufacturing
- Other Food Manufacturing
For the 2017 reporting year, 1,585 facilities in the sector reported to the Toxics Release Inventory (TRI) Program. To track trends in P2 and other sustainable practices, the TRI Program analyzed the food sector’s TRI data to characterize: 1) the major subsectors contributing chemical waste managed and release quantities; 2) how these quantities have changed over time; and 3) the types of pollution prevention practices implemented. To read the complete Food Manufacturing Profile, see Chapter 22 of Green Energy to Sustainability: Strategies for Global Industries.
Waste Managed and Releases
For TRI reporting, the quantity of “waste managed” includes TRI chemical waste managed through recycling, energy recovery, treatment or release to the environment.
Source: U.S. EPA Toxics Release Inventory – 2017 National Analysis Dataset
- Between 2007 and 2017, TRI-reported chemical waste managed by the food manufacturing industry increased by 45%.
- The increase was driven by the Grain/Oilseed Milling, Meats, and Dairy subsectors.
- Quantities recycled, treated, and used for energy recovery increased during this time, while quantities released into the environment decreased.
- From 2007 to 2017, releases of TRI chemicals reported by food manufacturers decreased by 10%.
- The Meats subsector accounted for the greatest quantity of releases to the environment, which are often in the form of nitrate compounds formed in wastewater and then discharged to surface water. Meat facilities are often concentrated near facilities raising livestock.
- Facilities in the Grain/Oilseed Milling subsector were responsible for the second-greatest quantity of releases to the environment. These releases were primarily air emissions resulting from the use of volatile chemicals to extract and process oils. These facilities are concentrated in central U.S. states such as Illinois, Indiana, and Iowa.
Chemicals
The TRI chemicals released in the largest quantities in 2017 for each subsector are shown in the table below.
| Subsector | Top Chemicals Released (Based on Quantity) |
|---|---|
| Animal Food | Nitrate Compounds1, Ammonia2, Acetaldehyde |
| Grain/Oilseed Milling | n-Hexane3, Hydrochloric Acid, Barium Compounds |
| Sugar and Confectionery | Ammonia2, Methanol, Nitrate Compounds1 |
| Fruit and Vegetable | Nitrate Compounds1, Nitric Acid, Ammonia2 |
| Dairy | Nitrate Compounds1, Toluene, Ammonia2 |
| Meats | Nitrate Compounds1, Ammonia2, Sodium Nitrite |
| Seafood | Ammonia2, Nitrate Compounds1, Chlorodifluoromethane |
| Bakeries and Tortilla | Ammonia2, Sulfuryl Fluoride, Sulfuric Acid |
| Other Food | Nitrate Compounds1, Methanol, Hydrochloric Acid |
Nitrate compounds and/or ammonia are among the top three chemicals released for almost every Food subsector, and these chemicals, along with n-hexane, are the top three chemicals released and managed as waste for the entire Food sector. The manufacture, processing or otherwise use of these chemicals (and the waste management methods chosen for them) are largely associated with specific subsectors:
- Nitrate compounds are manufactured as a result of nitrification during aerobic biological treatment of ammonia in wastewater. They are also manufactured when nitric acid, used for cleaning and sanitation, is treated (neutralized) prior to wastewater discharge. The Meats and Dairy subsectors are the biggest contributors of waste managed and releases quantities of nitrate compounds.
- Ammonia is often used to sanitize food manufacturing equipment and may also be formed by mineralization of organic nitrogen-containing waste. Releases and treatment of ammonia are largely dominated by the Meats subsector. However, more than half of ammonia waste is managed through recycling, and mostly reported by Grain/Oilseed Milling facilities, where ammonia is used during pre-treatment in the wet corn milling process to improve yields.
- n-Hexane is used within the Grain/Oilseed Milling subsector to extract and process a variety of oils from raw agricultural commodities. This subsector of the food manufacturing industry accounted for most of the n-hexane waste reported to the s TRI Program. As a volatile chemical, n-hexane releases were almost entirely to air.
Source Reduction Activities Reported to TRI
Reduced environmental releases of TRI-covered chemicals are driven in part by the implementation of source reduction activities. Each year, facilities report their newly implemented source reduction activities to TRI.
- The top three chemicals for which source reduction activities were reported were ammonia, nitric acid, and nitrate compounds, which were also the most commonly reported chemicals each year.
- TRI facilities most often implemented “Good Operating Practices”. Under this source reduction category, facilities specified improved maintenance, record-keeping, and procedures. “Process Modifications” were also frequently reported, and most often comprised of optimized reaction conditions or modified equipment, layout, or piping.
Sustainability Activities in Food Manufacturing
Along with source reduction, the food manufacturing sector has achieved further sustainability gains by implementing preferred waste management practices such as recycling and treatment. These include:
- Process and technology modifications implemented to reduce energy consumption and use less toxic chemicals
- Example: Reducing energy use by placing ovens in areas away from processes requiring cooler environments
- Example: Reducing toxic chemical use by replacing bisphenol A in food packaging
- Recycling of food packaging and organic waste to reduce environmental impacts after the useful life of a material
- Example: In the Seafood subsector, reusing skin, bone, and fin as fish meal and fertilizer.
- Wastewater treatment to destroy TRI chemicals
- Example: Transitioning away from traditional disinfectants for treating wastewater (e.g., chlorine) and using alternative technologies, such as ultraviolet treatment systems.