Fully Integrated Membrane Processing System

We were commissioned by a client to design and deliver a fully integrated membrane-based processing system capable of handling 60,000 litres per hour of standard cheese whey at 6.3% total solids (TS). The primary objective of the project was to produce 60% whey protein concentrate (WPC) while simultaneously recovering, concentrating, and reusing the permeate streams generated throughout the process. This required a carefully engineered combination of ultrafiltration (UF) and multi-stage reverse osmosis (RO) systems, each designed to operate continuously, efficiently, and with the flexibility required for a modern dairy processing environment.

The whey feed, supplied at a consistent flow of 60,000 L/h, first enters the ultrafiltration (UF) system, which is responsible for separating the protein-rich retentate from the lactose- and mineral-rich permeate. The UF plant we designed consists of four recirculation loops, with each loop divided into two membrane banks to ensure optimal flux, stable transmembrane pressure, and ease of maintenance.

Under normal operating conditions, the UF system produces:

•  3,333 L/h of 60% WPC at 12.8% TS, forming the high-value protein concentrate stream
• 56,667 L/h of UF permeate at 5.57% TS, containing lactose, minerals, and non-protein nitrogen

The UF permeate stream is then directed to the first stage of reverse osmosis. The goal of this RO stage is to further concentrate the dissolved solids to 24% TS, significantly reducing the volume of liquid requiring downstream handling while recovering a large proportion of permeate suitable for further processing.

The first RO plant, designed with seven recirculation loops, processes the full 56,667 L/h of UF permeate. The multi-loop configuration ensures stable operation at high recovery rates, minimises membrane fouling, and allows for fine control of cross-flow velocities. From this stage, the system yields:

• 12,879 L/h of RO concentrate at 24% TS, suitable for further processing, evaporation, or ingredient applications
• 43,788 L/h of RO permeate, a low-solids stream that forms the feed to the polishing RO stage

The RO permeate from the first stage contains only trace levels of dissolved solids and is therefore an excellent candidate for water recovery. To maximise reuse potential and meet the client’s internal water-quality specifications, the permeate is passed to a second RO plant designed specifically for polishing. This unit consists of two

recirculation loops, providing the necessary membrane surface area and hydraulic stability to achieve very high permeate purity.

The polishing RO system processes the full 43,788 L/h of first-stage RO permeate and produces:

• 39,409 L/h of polished water, meeting the quality requirements for recovery and reuse within the facility
• 4,379 L/h of concentrate, containing the small residual solids load removed during polishing and suitable for controlled disposal or further treatment depending on site requirements

This multi-stage membrane solution provides the client with a highly efficient, low-energy method for valorising whey streams, reducing waste volumes, and recovering a substantial proportion of process water. The system was fully commissioned, performance-tested, and integrated into the client’s existing operations. It delivers consistent product quality, stable throughput, and significant reductions in both effluent load and freshwater consumption.