Feasibility, safety, and economic implications of whey-recovered water in cleaning-in-place systems: A case study on water conservation for the dairy industry.

Water scarcity is threatening food security and business growth in the United States. In the dairy sector, most of the water is used in cleaning applications; therefore, any attempt to support water conservation in these processes will have a considerable effect on the water footprint of dairy products. This study demonstrates the viability for recovering good quality water from whey, a highly pollutant cheese-making by-product, to be reused in cleaning-in-place systems. The results obtained in this study indicate that by using a combined ultrafiltration and reverse osmosis system, 47% of water can be recovered. This system generates protein and lactose concentrates, by-products that once spray-dried fulfill commercial standards for protein and lactose powders. The physicochemical and microbiological quality of the recovered permeate was also analyzed, suggesting suitable properties to be reused in the cleaning-in-place system without affecting the quality and safety of the product manufactured on the cleaned equipment. A cost analysis was conducted for 3 cheese manufacturing levels, considering an annual production of 1, 20, and 225 million liters of whey. Results indicate the feasibility of this intervention in the dairy industry, generating revenues of $0.18, $3.05, and $33.4 million per year, respectively. The findings provide scientific evidence to promote the safety of reuse of reconditioned water in food processing plants, contributing to building a culture of water conservation and sustainable production throughout the food supply chain.