Water conservation is a challenging yet essential task for food and beverage processors globally. Water is crucial to production processes, with its quality and quantity varying by location and product type. The availability and cost of clean, fresh water, along with wastewater treatment implications, are key factors in achieving good water stewardship.
For early adopters, many straightforward improvements, like eliminating once-through cooling water or implementing brine recovery RO systems, have already been made. For facilities that have optimized their water-to-product ratio, advanced wastewater treatment for direct discharge or reuse is the next step. However, many food processors in North America, both large and small, lack dedicated water resources but can still make significant sustainability gains without large capital investments.
“We often see opportunities for immediate gains by optimizing primary water treatment systems,” says Barry Reicker, Vertical Market Manager for Evoqua. “Reverse Osmosis (RO) is widely accepted in feedwater treatment, but depending on the source, RO can only be 75-85% efficient. A simple brine recovery RO can increase efficiency to over 95% with minimal capital investment. Similarly, improving water quality fed to boilers and using inexpensive filtration for cooling tower water can enhance efficiency and longevity.”
For those who have already optimized production processes, water conservation can lead to higher strength wastewater. This illustrates the inherent trade-off between reducing water usage and managing wastewater.
Addressing Sludge in Wastewater Treatment
Water and wastewater costs are inevitable for the food processing industry. “Despite its long history, organic wastewater treatment is often misunderstood,” says Reicker. “In North America, food and beverage processors produce a variety of products, each with unique wastewater treatment needs. Meat processors, for instance, deal with high levels of fats, oils, and grease, while soft drink producers manage high soluble BOD levels. Effective wastewater treatment depends on the specific products and local discharge limits.”
Best practices in wastewater treatment balance current compliance costs with future production and reuse goals. “The most overlooked cost in wastewater treatment is sludge handling,” says Mike Jager, Product Manager for Evoqua. “Businesses often underestimate the cost and frequency of hauling high-strength waste. Dewatering materials intended for offsite hauling reduces both the volume and cost of disposal.”
Dewatering also opens up sustainability opportunities by allowing water reuse. By cleaning and reusing water from production byproducts, processors can reduce both their water usage and waste disposal costs. Reused water, depending on its quality, can be employed in applications like initial rinses in CIP processes, boilers, and cooling towers, offering significant cost savings and environmental benefits.
Infrastructure and Water Reuse
“Applications like cleaning, washdowns, boilers, and cooling towers are ideal for reused water,” says Reicker. Recapturing and treating water from various sources to displace freshwater demand not only reduces costs but also alleviates the strain on public treatment systems.
Discharge limits are tightening, prompting many food processors to adopt more advanced wastewater treatment methods. Nutrient discharge limits and concerns over total dissolved solids are becoming more prevalent, especially on the West Coast. As regulatory expectations grow, so does the need for effective wastewater treatment strategies.
The Case for Wastewater Reuse
Environmental regulations, cost considerations, sustainability goals, and water scarcity underscore the importance of reusing wastewater. CIP, washdowns, boilers, and cooling towers offer the best return on investment for wastewater reuse. Anaerobic digestion is gaining popularity for its low operating costs and biogas production, which can be used within the plant. This primary treatment step allows reuse systems to be sized to meet demand, enhancing circular water efficiency.
Assessing current practices and setting clear goals is essential before implementing wastewater reuse. “With the right processes and equipment, savings in water usage and waste disposal can be substantial,” says Jager.