From waste to value: Mitigating the environmental impact of whey in Jalisco, Mexico

Abstract

Whey, a liquid by-product of cheese and yogurt production, represents a substantial environmental challenge in the dairy industry. This study focuses on Jalisco, Mexico, a major dairy-producing region, to assess the environmental impact of whey disposal. Through a combination of physicochemical analysis, geographic information systems, and Life Cycle Assessment (LCA), we investigated the current whey management practices and their associated environmental burdens. Whey samples from 19 dairy processing units were analyzed, revealing high organic loads with biological oxygen demand ranging from 9.42 to 50.05 g/L, and total nitrogen and phosphorus levels of 1019.93 mg/L and 171.72 mg/L, respectively, exceeding local and international discharge limits. The region produces approximately 322,942 m³ of whey annually, with 67 % concentrated in 10 municipalities. LCA compared three whey management scenarios: direct disposal (DD), anaerobic digestion (AD), and whey powder (WP) production. DD contributed to freshwater and marine eutrophication (0.26 kg P eq and 0.23 kg N eq, respectively). AD emerged as the most sustainable option, reducing greenhouse gas emissions and generating biogas as a renewable energy source. WP production, while adding economic and nutritional value, had a global warming potential of 96.89 Kg CO₂ eq due to energy-intensive processing. Centralized treatment systems were identified as a viable solution for small producers, enabling shared infrastructure and cost reduction. These findings provide a scalable framework for sustainable whey management strategies, applicable to other dairy-producing regions.