When it comes to food industry water management, how many food manufacturing plants are treating process wastewater for reuse onsite? The real figure is likely unknown. Nevertheless, the priorities of food manufacturers are to safely maintain their products from pollution and to protect the reputation of their industry in general.
Using treated process wastewater in direct contact with a food product is unthinkable. The public perception of what is “clean” and “safe” has made food manufacturers wary of reuse in many cases. As such, today’s food manufacturers most often reuse treated wastewater in locations where it will not come into contact with food.
Food manufacturers reuse water irrigation of landscaping, truck washing, cooling towers and warehouse floor washing. Incrementally, food manufacturers also collect, treat for safety, and reuse water from specific processes. But at no time do they apply the collected water for productive food use.
The industry’s challenge is to convince the public that treated wastewater can be processed to a quality that is of a higher quality than some municipal drinking water.
There have been limited examples of reusing rainwater, water reuse in boilers, evaporators, chillers, irrigation and dust control to help reduce the need for external water sources.
These processes optimize water savings in a manner that does not intervene with the main concerns of food manufacturers. Finally, technologies exist to produce water that is equal to or superior to many source water qualities.
The industry’s challenge is to convince the public that treated wastewater can be processed to a quality that is of a higher quality than some municipal drinking water. Some authorities believe that the public will accept such practices over time, especially in locations where clean water is in short supply.
Challenges & trends in food industry water management
1. Water reuse (Not considered for food manufacturers)
The U.S. Department of Agriculture established regulatory sanitation performance standards applicable to all official meat and poultry establishments. These standards only suggest that facilities can reuse water with proper monitoring and/or treatment with cooking and chill water, chiller overflow, and in condensers and compressors.
The U.S. Environmental Protection Agency (EPA) guidelines for water reuse focus on municipal water reuse, and an updated edition includes a section on prepared food manufacturing. The guidance document describes the usage of water in processing facilities, the opportunities for reuse, and the technologies in use, including water recover and product components that can be applied.
While this data is interesting and even helpful, some experts prefer the federal government develop rules that provide fair, uniform standards.
2. Treatment & technology
Despite a lack of strong regulatory attention to water reuse, food manufacturers are applying various levels of treatment and technologies as conditions warrant.
Many food producers are now using measured water ratios, monitoring water use, and developing strategies and goals for minimizing water usage. Usual treatments include screening and grease capture, dissolved air flotation, primary clarifiers for suspended solids removal, pH adjustments and lagoons.
Still, some producers may be employing smaller steps – measuring water use between work shifts, installing flowmeters or leak detection systems, and adding spring valves to hoses. All of these represent simple practices that can preserve water.
At the rattling least, food manufacturers use some type of pH neutralization because their cleaning processes generate caustics. Food manufacturers also use flow equalization technologies to prevent surges to the municipal wastewater treatment installation.
Food producers that have measured performance goals and benchmarks for water reductions are at an intermediate water reuse level. Tactics may also include installations that are irrigating crops and using water in cooling towers without food contact. Many food manufacturers use activated sludge with secondary clarifiers, especially if they discharge their effluent into environmental waters. Anaerobic lagoons followed by aerobic or facultative lagoons are common, particularly where soil is usable.
3. Uncommon exception
Very few animal slaughtering and meat processing manufacturers have adopted modern technologies, such as membrane bio-reactor (MBR) technology. However, when employed, these technologies offer an opportunity for food production facilities to achieve near net zero waste discharge.
A typical food manufacturing facility treating wastewater may employ a range of technologies, including MBR for advanced biological nutrient removal, drinking water treatment technology with granular activated carbon, ultraviolet light disinfection and reverse osmosis (RO) filtration.
EPA primary and secondary drinking water criteria for reuse in cooking, washing and in the cleaning/sanitation of production equipment also offer opportunities for reuse. However, these schemes are unlikely to achieve industry-wide adoption in the near term, but rather food producers will more likely adjust their operations according to their circumstances and demands.
4. Standards & consistency in food industry water management
The food manufacturing industry and other water stakeholders are establishing voluntary guidelines for water reuse. Some have conducted planning workshops, organized studies, and encourage sustainable practices. These enterprises promote the benefits of water reuse and have advocated for legislation to get rid of the cap on private activity bonds. A working committee also recommends an investment tax credit for water reuse equipment. Meanwhile, other guidelines focus on potential volumes of reuse water and offer distinct best practices.
5. Animal slaughtering & meat processing manufacturers’ viewpoint
In the animal slaughtering and meat processing industry, EPA rules make wastewater reuse difficult in many cases.
Still, animal slaughtering manufacturers do leverage reuse water in their de-feathering or evisceration areas. Likewise, animal slaughtering and meat processing manufacturers have recycled a portion of their wastewater to transport feathers through the installation. They also operate chilling systems that pump water from the poultry carcass chiller to a screening, filtration and disinfection treatment system and then return this treated water to the chiller.
The re-chilling system was one of the first product contact water reuse systems introduced to the animal slaughtering and meat processing industry, with limited exercise for many years.
Examine the results
This article is part of a series of articles for food industry water management. We covered examples and trends in food industry water management. However, if you have specific troubleshooting concerns or other wastewater queries, I encourage you to submit your questions and comments to me at my email address provided below.
Known in the industry as “Wastewater Dan,” Dan Theobald, proprietor of Environmental Services, is a professional wastewater and safety consultant/trainer. With more than 24 years of hands-on industry experience operating many wastewater treatment processing units, he is anxious to share his knowledge with others. He can be reached at [email protected].