Experimental Study on Dairy Industry Wastewater Treatment Using Membrane Technology: Performance Evaluation and Process Optimization

The dairy industry is one of the most water-intensive sectors within the food manufacturing domain, producing large volumes of wastewater rich in organic matter, fats, proteins, and suspended solids. Conventional biological and physicochemical treatment systems often fail to meet increasingly stringent discharge regulations or to achieve the quality required for water reuse. Membrane technologies—microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO)—have emerged as viable alternatives offering compact design, modular scalability, and high effluent quality. This paper presents an experimental investigation into the treatment performance and optimization of a pilot-scale membrane system for dairy wastewater. Simulated influent with chemical oxygen demand (COD) ranging from 2 500 to 3 800 mg L⁻¹ and biochemical oxygen demand (BOD₅) between 1 100 and 1 700 mg L⁻¹ was treated using an integrated MF–RO configuration. Performance metrics included flux behavior, pollutant rejection efficiency, and permeate quality, which were analyzed across a range of trans-membrane pressures and cross-flow velocities. Results demonstrated COD and BOD removal efficiencies exceeding 90 %, stable flux recovery through periodic backwashing, and permeate quality compliant with ISO 14001 discharge standards, indicating strong potential for internal process water reuse. The study contributes to advancing practical understanding of energy-efficient dairy effluent treatment using hybrid membrane systems and highlights optimization strategies for industrial scale-up.