Date of this Version
Meneses Yulie E.. 2016. Feasibility, safety, economic and environmental implications of whey- recovered water in cleaning-in-place systems: A case study on water conservation for the dairy industry. University of Nebraska. Doctoral Dissertation
Several countries around the world are facing the challenge of producing food with limited water resources for a growing population. This reality is forcing all sectors involved in the food supply chain to look for water conservation strategies that contribute to assure global food security. Besides water consumption, the food industry has to deal with wastewater generation; therefore, water reconditioning and reuse is an attractive solution to address both issues. The goal of this research was to demonstrate that high quality water can be recovered from whey, a by-product of the cheese making process, and reused in cleaning-in place (CIP) operations. Technical, economic, safety and environmental feasibility of the proposed intervention was also considered. First, the performance of the water recovery system was evaluated as well as the quality of protein, lactose and water recovered from whey. A combination of ultrafiltration and reverse osmosis allowed a water recovery of 47 % with > 98 % removal of the initial pollutants present in whey. Once spray dried, protein and lactose powder fulfill commercial standards. When applied in CIP systems, the cleaning efficiency of the recovered water was proven to be similar to tap water. Subsequently, a cost analysis was performed for small, medium and high cheese production scales; results demonstrated that the proposed intervention is economically feasible generating revenues of 0.18, 3.05 and 33.4 million $/year, respectively. Then, a comparative life cycle assessment was conducted, revealing that the recovery system generate 87.7 % and 18% lower environmental impacts than a wastewater and water production system, respectively. Energy usage was the input causing most of the emissions. Lastly, the risk assessment on the reuse of contaminated-reconditioned water with L. monocytogenes in fluid milk processing, indicated low levels of bacteria transferred from the contaminated water to the equipment surface.
Advisor: Rolando A. Flores