Nanofiltration of UHT flash cooler condensates from a dairy factory: Characterisation and water reuse potential Original Research Article

The large consumption of water in the dairy industry makes water reuse a crucial issue. Flash Cooler (FC) condensates from direct ultra high temperature (UHT) treatments were characterised and nanofiltered in order to obtain potentially reusable water depending on the limitations of its end uses. A nanofiltration (NF) pilot plant (1.6 m2 membrane area) with a SelRO MPS-34 2540 B2X (Koch Membrane Systems) was used for these purposes. The influence of operating conditions (transmembrane pressure (TMP), temperature, time and water recovery) on permeate flow rate (J) and quality (conductivity, chemical oxygen demand (COD), total organic carbon (TOC) and Ca2 +) was studied. Heating (taking into account the thermal potential of condensates) and other miscellaneous objectives were achieved, a volume concentration ratio (VCR) of 8 being set as a design parameter. The experimental data was used to design a NF plant with 20 m3/h feed capacity whose savings and operating costs were estimated at 2.807 and 0.777 €/m3, respectively.