Performance comparison of micro-nano bubble, electro-oxidation and ozone pre-treatment in reducing fluoride from industrial wastewater

Micro-nano bubble, electro-oxidation and ozone treatment of wastewater is widely accepted. In this study the effect of these technologies as a pre-treatment process in removing fluoride was observed and compared. The wastewater from Kumho Petrochemical Co. Ltd. (final product is synthetic resins) containing BF3 was infused with micro-nano bubble, electro-oxidation and ozone gas for 2 h and then pH adjustment was done by adding Ca(OH)2. PAC 11%, F900 and Alum were used after that and then polymer was added. The micro-nano bubble pre-treatment shows better removal percentages than those of electro-oxidation and ozone pre-treatment. The combination of F900 and A-polymer with micro-nano bubble pre-treated wastewater seems to have a higher fluoride removal percentage than the other combinations (76.7%) whereas without pre-treatment, the maximum fluoride removal percentage was observed to be 69.6%. %. Therefore, an increase of 7.1% was obtained over traditional treatment for air bubble pre-treatment. For electro-oxidation and ozone pre-treatment, fluoride removal percentages were somewhat within the same range with no pre-treatment values. In case of COD removal, the combination of F900 and A-polymer with micro-nano bubble pre-treated wastewater was observed to be the best (63.6%) whereas without pre-treatment, the maximum COD removal percentage was observed to be 54.9%. For electro-oxidation and ozone pre-treatment, COD removal percentage was found without the range of 31.4%-47.5%, which is even lower than without pre-treatment values.