Combined microbubble ozonation-BAC system for reverse osmosis concentrate treatment

摘要

Microbubble ozonation was used to increase ozone utilization rate and to enhance ozone oxidation of reverse osmosis concentrate (ROC) followed by biodegradation using a BAC system. The average influent COD and BOD5/COD of ROC to microbubble ozonation system were 240 mg/L and 0.01, respectively. With the continuous operation of a lab-scale microbubble ozonation system under an optimum condition with 40mg/L O3 dosage and 30 mins HRT, the average COD removal obtained was 55% with an increase in BOD5/COD ratio from 0.01 to 0.25. Under the optimum operating condition, the average ratio between COD removed and O3 consumed was 1 ;2.5. Microbubble ozone treated ROC was then fed in to a biological activated carbon (BAC) column for further biodegradation of ROC. Combining the BAC column at 120 mins EBCT with microbubble ozonation was able to increase the COD removal efficiency 2-3 times higher as compared without pre-ozonation. With the lab-scale combined microbubble ozonation and BAC system, the average effluent COD of 35 mg/L was achieved that can meet the COD discharge limit standard.