Reclamation of dairy wastewater using ultrafiltration process

Large amounts of water are daily used in dairy industries for different parts of their services such as chilling, cooling, steam production, pasteurizing, etc. This consumption generates a huge quantity of wastewaters which could be reused after performed treatment. In the present work, a real sample of dairy wastewater was treated using ultrafiltration (UF) and process efficiency and permeate quality were improved by operating under optimum conditions of transmembrane pressure (TMP) and volume reduction factor (VRF). More than 99% of retention rate were observed for turbidity and the BDO5, more than 80% for suspended matter, and 95% for proteins with an optimal TMP fixed at 2.5 bar. Moreover, a reduction of 40 and 55% was recorded for conductivity and the total dissolved salts, respectively. Rather important retention rates varying from 95 to 99% for the majority of the analyzed parameters were observed for a VRF range varying from 1.11 to 2.5. A recovery of 58% of the dairy effluent is possible after treatment by UF using the PES-5 membrane. The permeate quality obtained in optimal TMP and VRF allows the industry to reject its effluents into the river without risks of contamination (according to Tunisian standard for wastewater discharge NT106-02) and to reuse or recycle them during the process (according to Tunisian standard for reusing treated wastewater NT106-03).