Sucrose Removal from Cane Sugar Mill Waste Streams by Ion Exchange.

摘要

Small amounts of sucrose in sugar mill waste water were removed by hydrolyzing sucrose to glucose and fructose and then removing these sugars by complexing with boric acid held on an ion exchange resin. Hydrolysis of sucrose utilized the enzyme invertase as a catalyst. Attempts were made to immobilize invertase on various solid supports. Best activity and stability were obtained with iodine substituted invertase on Duolite phenolic resin treated with gluteraldehyde. The immobilized enzyme was uneconomical,so the preliminary design was based on direct addition of invertase to the waste water. Removal of glucose/fructose from solution was studied using Amberlite IRA 400 (strongly basic anion exchange resin) in the borate form. Three hundred bed volumes of a solution containing 100mg glucose plus 100mg fructose per liter could be treated at a rate of 50bed volumes per hour before breakthrough of sugar into the effluent. Boric acid in the effluent could be reduced to less than 10ppm by passing through a second column of resin in the hydroxyl form. A preliminary design and economic study was made based on treating 5MGD of condenser cooling water containing 200ppm sucrose. The process produces 5MGD of pure water (<10ppm sugar; <10ppm boric acid) for reuse. It also produces 167,000 GPD of a concentrated waste containing 6000ppm sugar plus boric acid and HCl. Capital investment was estimated at $1,500,000. Predicted operating costs were $1.45per 1000gallons of water treated. The process appears uneconomical in its present form as compared to conventional biological treatment methods.