Milk and Water Don’t Mix

The State of Wisconsin, in the upper Midwest of the United States, is known as one of the premier cheese-making regions of the world. Producing more than three billion pounds of cheese annually, the state is home to countless producers – some local providers and some shipping to all parts of North America and beyond.

One such dairy-products producer manufactures several lines of quality cheese for local pizzerias and restaurants, from Asiago to Parmesan; ricotta to mozzarella. Their plant also produces specialty whey products to international food-and-beverage manufacturers, to improve the taste, texture, and nutrition of their products.

When building the plant in 2011, a wastewater treatment system was needed to handle the residual waste from the food manufacturing process. But handling wastewater from milk processing can be tricky, imposing significant challenges for the operator:

• high-temperature wastewater that is greasy from the oils and fats from milk
• long-term maintenance of the system without losing production time (shutting down the plant for routine maintenance is not an option, as decreased production means decreased output which costs a company money)
• for this plant, the effluent was to be released back into the environment (the local watershed), which required much tighter permit levels versus releasing the effluent into the local sewer system for additional treatment downstream

Calling in the Experts

The company called on Energenecs, a water and wastewater integrator in the upper Midwest, to oversee the design and construction of the plant. After working through the details and the requirements spelled out in the RFP, Environmental Dynamics International® (EDI), an Axius Water Company, was chosen to address the specific dissolved oxygen needs.

Given the high temperature (160°) and “industrial strength” influent coming into the wastewater processing system, the EDI team engineered, designed, and manufactured a custom ModuleAir™ system with EDI specialty membranes, to handle the harsher wastewater. For air diffuser systems like this one, there are many different options as to the type of membrane chosen – from EPDM rubber, Armor-Coated™ EPDM, or high temperature urethane. With the greasy wastewater created from milk processing, the membranes need to reduce organic and inorganic fouling over the long-term, minimizing replacement and maintenance as much as possible. And in this type of environment, membrane replacement is recommended every three-four years, with annual inspections to ensure that oxygen transfer efficiency and stringent permit requirements – for the effluent discharging into the local watershed – are still being met.

Time is Money

As with any manufacturing or process facility, if the plant is operating then the plant is producing. So keeping the operation up and running is paramount – shutting it down is not an option unless under the most dire of circumstances. Time is indeed money. When designing the diffuser system, EDI incorporated this “time is money” mindset into the long-term, ongoing maintenance needs for the plant. To simplify the maintenance process, and to keep the plant online during regular maintenance activities, the aeration system was designed to be a modular system. Isolation valves were incorporated at each of the drop pipes feeding the aeration tubes, allowing operators to shut down separate “modules” for ongoing maintenance without shutting down the entire plant. The components can then be lifted out of the basin with a crane, for the work to be done on solid ground outside the tank and then put back into place.

So Far So Good

As world class as the cheese products are from this purveyor, the wastewater treatment processing system at their facility is also world class, providing a modular approach to maintenance, for long-term ease and efficient upkeep. And it’s a solution that, over the years, has served the customer well. With the plant in operation since 2011, and regular membrane replacement throughout the life of the plant, the wastewater treatment solution put in place at the time has been operating as designed. This has allowed the owner/operator to focus their efforts on producing high-end cheese and whey products, and not having to worry about meeting their permit requirements.