In “The Amazing Spider-Man” movies, Uncle Ben, and more recently Aunt May, utter the iconic phrase, “With great power comes great responsibility,” encouraging Peter Parker, aka Spider-Man, to don the blue-and-red suit and attune his “spidey senses” to imminent danger. Recognizing the dangers of climate change and global warming, dairy manufacturers, processors and plant managers are creating sustainability initiatives to reverse course on carbon emissions and equip plants with cost-saving equipment and the ability to effectively manage water and energy resources.
Mike Parsey, vice president of process engineering automation and design at Shambaugh & Son L.P., points out that dairy processing requires equipment and methods that are typically more reliant on electrical (motors) and thermal (product temperature) needs than other food products.
“The dairy processing industry is a highly regulated industry,” and as such, “Some of the rules and requirements for the processing of dairy products create energy consumption needs, that might not otherwise be required,” he says.
When it comes to designing and building a new facility, Parsey suggests that the conceptual design process is the “opportune time” to set innovative and effective sustainability goals.
A specialty design, construction, and engineering firm in Fort Wayne, Ind., the company notes that strategy is crucial for designing the sustainable dairy plant of today — and tomorrow. “The food process engineering design team can strategize how to design and ongoingly manage operational emissions,” Parsey explains. “This will help to ensure that every design aspect of the building, the facility grounds, the materials, the equipment, the management of water, and the management of energy resources can have an inherent ability to contribute to the curtailment of greenhouse gas (GHG) levels and the use of fossil fuels for the production of the dairy products to be produced.”
Parcey notes that while plant strategy will likely consist of attainment and utilization, clean/renewable, and efficient energy on-site and off-site sources, a life cycle assessment is of “utmost importance” to determine the degree of reliability and accuracy of the facility calculations alignment of GHG protocols, particularly as the plant comes online and new dairy products are manufactured.
Jacqueline Bruntjen, director of sustainability for Springfield, Mass.-based Dennis Group, adds that a greenfield gives dairy processors more flexibility to build in sustainable elements from the beginning. “Process water, heating, and cooling systems, mechanical systems, and wastewater are all areas to target for resource conservation,” Bruntjen says. “If the facility is producing milk powders or cheese, it’s possible to capture and reuse ‘cow water’ or water that is evaporated, condensed, and re-purposed. This water can be captured from the permeate evaporator and the upstream membrane processes.
“For example, if you have 4 million pounds per day of milk, 87.5% H2O, you can potentially recover 420,000 [gallons per day] gpd of water since the finished product contains very little water. The permeate and WPC powders only have 4% moisture. Mozzarella (48-52% water) and cheddar cheese (39% water) also don't contain much water,” she continues. “The Pasteurized Milk Ordinance has specific requirements for the water and how it can be used, and local health departments will determine the water designation and its possible uses to determine if this water is considered potable or non-potable.”
Furthermore, when evaporation is used in dairy processing, it generates a significant amount of heat. However, if a spray dryer is coupled with a properly designed waste heat recovery system, the plant's heating requirements can be reduced by 20%, Bruntjen says, adding that waste heat can then be used to pre-heat dryer air, generate process hot water, heat boiler feed water or ambient spaces.
Sustainability more than a buzzword
Noting that sustainability is no longer a buzzword, dairy processors are enhancing sustainability efforts within their existing facilities in myriad ways. For instance, by treating and reusing wastewater, installing LED lighting, retrofitting dairy plants with sensors that can monitor water, installing on-demand boiling systems, and more.
Among Pacey’s tips for sustainability success are to investigate the use of solar panels to generate hot water within the plant, evaluate the feasibility of on-site wind generators and solar arrays to supplement electrical power and create and store energy, respectively, and compare natural gas boilers with economizers and blow down heat recovery units with electric boilers that can be powered with clean energy and have zero emissions. He highly recommends installing software and analytics — a manufacturing execution system (MES) — to analyze entry and discharge point of water and effluent, respectively.
Ola Wesstrom, senior industry manager of food and beverage at Endress+Hauser, a family-owned, Switzerland-based operating process, and laboratory instrumentation and automation supplier, elaborates on a crucial ingredient for the dairy industry – milk — and the best way to decrease losses in milk receiving.
“By enhancing the accuracy of milk receiving and plant mass balance measurement points throughout a facility, a distinction between measurement error-based and actual product (milk/cream/whey) losses can be identified,” Wesstrom relays. “For example, incoming milk contains 2-10% air by volume. By equipping dairy processing facilities with Coriolis mass flowmeters instead of traditional volume-based magnetic flowmeters, the actual quantity of product can be accurately accounted for.”
Additionally, she notes that transporting a dairy plant into the “sustainable dairy plant of the future” can be aided by simply adding phase separation sensors (e.g., optical-, density- or conductivity-based) at transfer points. “[These] processors can ensure minimal amounts of product, water and detergent are wasted during changeovers, or transitions to and from CIP,” she adds, noting that these types of cost-saving equipment modifications can save dairy companies money in water and energy usage while reducing fuel and GHG levels.
Bruntjen expresses similar sentiments. “Heating and cooling functions are inherent to milk processing and residual energy streams can be harnessed to pre-heat and pre-cool other systems,” she says. “For example, wastestreams from the heat intensive pasteurization process can be captured and used to pre-heat boiler make-up water or warm ambient spaces, reducing overall energy usage.”
Energy-saving equipment reduces NOx emissions
While plant processes and utility mechanical devices lose power over time, Bruntjen highlights ways to combat inefficiencies. “The first step to reduce a facility's energy/carbon usage is to understand which devices are the most significant energy users (refrigeration systems, boilers, HVAC equipment, air compressors, etc.) and their end-of-service lifespan,” she says. “Reviewing if the devices are sized appropriately for the intended work can uncover inefficiencies that can be corrected with simple changes such as downgrading motor size to perform the same work.” Utility companies often offer rebates for replacing larger energy-using devices, which offset capital costs, she adds.
When it comes to saving energy from large equipment pivotal to a dairy processing plant, an on-demand boiler system can fulfill an important need state, according to Andrew Eklind, marketing manager, and Hayley Schmitt, marketing content writer, at Rockmart, Ga.-based Miura America Co. LTD.
They explain that while steam boilers are one of the most fundamental systems in a dairy plant, literally responsible for keeping a plant humming along, steam boilers nevertheless use a large amount of natural gas and electricity. Yet, considerable improvement has been made with today’s steam-producing boilers, which produce thousands of tons of steam per hour, typically with a fuel-to-steam efficiency as high as 90%.
In order to meet new corporate sustainability goals and regional government regulations, today’s steam boiler industry is laser-focused on NOx reduction, according to Eklind and Schmitt.
A modular, on-demand boiler system that fires up only when necessary can make a big difference in the reduction of NOx emissions and fuel usage. “… A dairy plant would only use the number of boilers needed to produce the steam demanded instead of wasting energy by overproducing unnecessary steam,” Eklind and Schmitt stated. “Miura’s system is designed to be low NOx with a standard economizer that recovers heat and premixes fuel with combustion air to raise the temperature while maintaining a low flame temperature.”
Design modifications offset carbon emissions
While major processes and systems within dairy manufacturing have remained relatively unchanged over the last decade, methods, approaches, and even software systems have evolved to reduce a dairy plant’s carbon footprint.
Parcey stresses the importance of data gathering through an MES, noting that this software system provides real-time feedback on the performance of the process and tracks utility usage, water usage, and effluent.
“The MES system would serve as the backbone of the overall energy management system for the plant,” Parcey notes.
Bruntjen advises that dairy plants identify high-priority projects and review their systems to see if design modifications can be made to reduce mechanical work.
“If in-house engineering resources are taxed, using a third party who has both process and utility engineers to perform an ASHRAE Commercial Building Energy Audit Level 2 will help expedite this initiative,” she says. “The most impactful carbon reduction strategy is onsite renewables. … installing renewable energy systems to offset your carbon emissions yields the most significant carbon reduction overall, ensuring the energy you are using is carbon neutral.”
The Dennis Group’s carbon audit work for the design of new dairy facility achieved cost- and energy-savings. “The base design case carried 28,740 MTCO2E carbon avoidance from the design baseline. Furthermore, we recommended energy savings opportunities that collectively have the potential to avoid an additional 67,330 MTCO2e of GHG emissions annually,” Bruntjen states.
Similarly, Shambaugh has a design team specifically oriented toward the dairy industry. It recently designed and constructed an award-winning Dairy Farmers of America (DFA) Milk Powder Drying facility in Garden City, Kan.
Resting on a 156-acre site, the state-of-the-art plant produces whole, skim, and nonfat dry milk powder as well as cream in partnership with the DFA and 12 member farms in southwest Kansas. Parcey explains that in the past, a tanker may have been gone for days but the new facility enables the same tanker to return same-day, saving time and money.
“North America’s largest whole and skim milk powder drying facility, the plant has the capacity to receive 4 million pounds of milk a day from regional dairy farms — 84 tanker loads a day,” Parcey says. “From the time the tanker comes into the plant, it takes approximately 68 minutes to off-load the milk, clean the truck, and test the milk. It is a huge advantage of this facility to be so close to the source of the milk. Drastically reduced are the hauling and trucking costs, not to mention the turn-around time for the dairy farmers, reducing the overall carbon footprint.”