Dairy Industry Waste Water Treatment Using a Simple Membrane Setup

This study investigates the treatment of dairy-industry wastewater using a simple, single-stage ultrafiltration (UF) system equipped with polyether sulfone (PES) and polyvinylidene fluoride (PVDF) membranes under laboratory-scale conditions. The influent exhibited high organic loading (COD ≈ 3,950 mg L⁻¹, BOD₅ ≈ 1,750 mg L⁻¹), characteristic of small dairy effluents. System performance was evaluated in terms of permeate flux, contaminant removal, and fouling behavior. Optimum operation was achieved at a transmembrane pressure of 2 bar, yielding average COD and TSS removal efficiencies of 78 % and 97 % for PES, and 73 % and 95 % for PVDF, respectively. Flux decline was primarily reversible, governed by cake-layer formation, and effectively mitigated through a two-step NaOH–citric acid cleaning protocol restoring over 90 % of the initial flux. The system operated with low specific energy demand (0.35 kWh m⁻³) and treatment cost (≈ 0.28 USD m⁻³), highlighting its potential for decentralized and small-scale dairy applications. The results confirm that simplified UF setups can deliver reliable effluent quality, operational stability, and economic feasibility for sustainable wastewater management in the dairy sector.