Recycling of oleochemical wastewater for boiler feed water using reverse osmosis membranes — A case study

Currently, awareness of water conservation has increased worldwide due to water scarcity. Wastewater recycling appears to be attractive for water conservation. This paper addresses a case study of oleochemical wastewater treatment using an advanced process that comprises ultrafiltration (UF) and reverse osmosis (RO) membranes. Prior to the membrane process, the oleochemical effluent was first treated using a biological treatment system that was installed by the factory owner. The quantity and quality of the permeate stream of the membrane system were then periodically monitored over 43days. The results showed that the system functioned effectively in reducing the chemical oxygen demand (COD), hardness content and the amount of total dissolved solids (TDS). However, the system started to deteriorate after 15days of operation. Membrane biofouling was suspected to have occurred in the RO membrane. Nevertheless, the fouling problem could be resolved by chemically cleaning the RO membrane using a sodium hydroxide (NaOH) solution every 3–5days. Despite of the fact that data set for a longer period is needed to provide a more comprehensive study on the biofouling mechanism of membrane, this study somehow reflects a real-life problem of the application of RO membrane in the water recycling industry in Malaysia. ►A case study of water recycling system using UF and RO membranes. ►Performance in terms of quality and quantity of permeate water was examined. ►Membrane biofouling was suspected to have occurred in the RO membrane. ►System achieved the initial design requirement of approximately 75% water recovery. ►A real-life problem of RO membrane in the water recycling industry in Malaysia.