Decolourization of Polyaluminium Chloride and Fungal Sequencing Batch Aerobic Reactor Treated Molasses Spentwash by Ozone

Molasses spentwash from distilleries is characterized by high COD and color. The treatment of distillery spentwash by coagulation with polyaluminium chloride(PAC) followed by biological treatment with fungal sequencing batch aerobic reactor(FSBAR) resulted in 87% decolorization. To achieve further decolorization, ozonation of treated distillery spentwash was carried out at different ozone doses and contact times. It was found that pH had a negligible effect on decolourization. The optimum ozone dose was found to be 4.75 g/L at application rate of 3.8 g/h for 30 min with corresponding decolorization being 66%. The overall decolorization obtained by the combined treatment(PAC treatment, FSBAR and Ozonation) was 96% and the total COD removal was 81%.