How Greek yogurt plants are turning whey into a money-making resource
Dairy processors find new uses for whey, which can't be sent to public water treatment works.
Whey, what most dairy processors produce as a byproduct of cheese making and yogurt production, just can’t be sent off to the publicly owned water treatment works (POTW) without pretreatment because of its large BOD and COD. And processors have realized that throwing this byproduct out is like throwing money down the drain when it and its derivatives can be sold to food processors and nutraceutical manufacturers as valuable input ingredients.
Problem is: Processing whey on site adds a complexity of more equipment to operate and maintain, and producing whey derivative products isn’t the yogurt processor’s forte. Thus, some processors offload whey processing to a third party, do enough pretreatment to meet the requirements of the POTW and/or sell off the rest to farms as a feed supplement.
But, what if separating equipment weren’t so complex to operate and maintain that it could just operate transparently as another process in the plant? What if separating equipment could run chemical free and be compatible with plant CIP processes? What if this equipment could occupy a relatively small footprint and operate continuously, accepting whey output from the dairy process and converting it into its constituent parts?
These are questions with which Trish Choudhary, PhD, founder and CEO of E-Sep Technologies, had been wrestling for some time, and has come up with some solutions. Choudhary has 15 years’ experience producing industrial proteins through bio-based innovation. She currently holds seven US patents for developing non-chemical industrial solutions for various industries including dairy—for which she has a patent pending for demineralization and separation of whey products. The E-Sep team boasts decades of experience in electrical engineering, mechanical engineering, software engineering, operations management and biotechnology. FE asked her to fill us in on the details.
FE: What were your goals in designing a system to handle whey output from a yogurt or cheese operation?
Trish Choudhary: We wanted to design a system that could: (1) completely demineralize whey in a single step for further processing into premium ingredient products, (2) reduce downtime/CIP cycles of downstream processes (evaporators/dryers) by preventing buildup of precipitated inorganic salts and (3) reduce the overall environmental impact associated with whey processing/disposal (no heat or chemical use).
Our proprietary process (ESEP 1000 system) runs solely on water and electricity and doesn’t use or release chemicals into the environment, hence an attractive platform for processing materials suitable for human/animal consumption. Our goal is to provide innovative, customer-driven solutions to dairy processing companies to enable efficiency, productivity and profitability while reducing any associated environmental impact.
FE: Yogurt processors often build a pretreatment facility to meet a POTW’s effluent requirements. What benefits could they derive from employing your separation system?
Choudhary: Our system is able to directly process acid whey derived from yogurt manufacture. The system is able to separate all the minerals from the lactose and simultaneously neutralize the acid whey (remove the lactic acid). By utilizing our process, the “effluent” that would normally require pretreatment and transportation to a POTW facility could now be processed just like sweet whey to produce viable products such as food and pharmaceutical grade lactose as well as milk minerals. Essentially, our single-step process can turn a liability into revenue for yogurt manufacturers.
FE: A cheese or yogurt maker probably doesn’t want to add more processing equipment to make secondary or tertiary products. Explain why your system will not add complexity to an existing operation.
Choudhary: The ESEP system has been designed for simplicity and efficiency. We have combined the operational ease of filtration technologies with the specificity of traditional resin-based ion exchange/electrodialysis technologies, but without the added cost of using harsh chemicals. Our system fully integrates in line with existing processing equipment and is fully automated for ease of operation (including automated CIP at the push of a button). Our system is equipped with smart technology (built-in temperature, pH, flow, conductivity, pressure sensors and programmable software), which enables the system to regulate itself and adjust power/flow according to programmed parameters for a consistent output of product. We designed the system to be “plug and play,” utilizing only recycled water from within the plant and a power source for low operating costs.
FE: In a nutshell, how does your separation system work?
Choudhary: A feed solution (whey, acid whey, UF retentate or permeate) is pumped into our ESEP 1000 module(s). As the feed stream passes through our patented membranes, all ions are extracted regardless of size, charge, valence (mono and multivalent ions), and a continuous “demineralized product” stream containing lactose or whey proteins exits the system. Periodically, water is pumped into individual cells within the module(s) to release the ions held within the membranes, and this is collected as a separate stream, without disrupting the continuous product stream.
FE: How does this separation technology compare with other membrane and/or filtration systems?
Choudhary: Nanofiltration primarily removes monovalent ions such as Na+, K+ and Cl-, but not multivalent ions such as Ca2+ and Mg2+ due to their high molecular weight. Whey demineralized by nanofiltration contains higher concentrations of multivalent ions, which negatively impact downstream processes. For example, buildup of calcium phosphate scale requires frequent shutdown of evaporators and dryers while chemicals are added to dissolve the scale. Presence of multivalent salts also negatively impacts lactose crystallization yields, and hence, excess volumes of mother liquor are produced requiring further disposal.
Traditional ion exchange is the only alternative for complete demineralization, but it requires large, individual cation and anion exchanger columns (two separate processes used in combination). Whey must be pH adjusted using large volumes of acid and base chemicals to drive the chemistry of the ion exchange resins. These chemicals can often cause a significant decrease in the biological activity of the biomolecules being isolated (e.g., in the case of proteins, causing various degrees of protein denaturation). Once the regeneration process has taken place, the bound ions (milk minerals) are stripped using acid or base and can no longer be utilized or further processed as functional milk minerals, and hence, the value of these products cannot be captured.
Our system removes all ions in a single pass irrespective of charge, valence or size (unlike nanofiltration), and we do not use any chemicals to drive the chemistry of separation (unlike traditional ion exchange). Downstream processes (including evaporators and dryers) are positively impacted as there is no formation of calcium phosphate scale, hence a dramatic reduction in downtime for cleaning and scale dissolution using chemicals. Along with process improvements, removing all of the salts from permeates prior to crystallization improves yields and the quality of the final lactose product. The milk minerals are also separated in water, allowing for further processing and an additional revenue stream.
FE: Is a POTW pretreatment system still necessary after installing your ESEP 1000 system?
Choudhary: No. Our system is designed to fit in line with cheese/yogurt production equipment and to process whey directly as it is being produced or immediately after ultrafiltration to separate whey proteins from lactose.