Membrane processes for water recovery and wastewater treatment in the food industry

Despite the efforts to reduce its water consumption,the food industry still requires large amounts of water. Membrane processes have established themselves in the food industry at the beginning of the water loop for preparation of the intake water and at the end water loop for recovery and final treatment of the water. The focus of this paper is on two application studies related to water recovery and water treatment in the food industry. The first study is on water recovery from tank washing water in customized liquid sugar production. During the washing of the tanks,sweet water with 1°- 5° Brix sugars is produced which is equivalent to a COD of 5000 - 25000 mg/L. By reverse osmosis,this sweet water can be separated into a sugar-free permeate for recycling and a concentrate with more than 20° Brix,which can be utilized as animal feed. The second study is on the effluent from production of modified potato starch,which is contaminated with spirochete bacteria resulting in problems in the wastewater treatment plant. By installing a membrane bioreactor,not only is this problem overcome but the general quality of the water at the discharge of the plant is improved. Overall,this paper demonstrates that membrane processes have a large potential in the water recovery and wastewater treatment in the food industry.