RESUMO
Medical laboratory wastewaters arising from diagnosis and examination units show highly toxic characteristic. Within the scope of the study, removal of the wastewater's toxicity and increasing BOD5 /COD ratio of the medical laboratory wastewaters through electro-Fenton (EF) process were investigated. In the study, central composite design was applied to optimize the process parameters of EF for COD, BOD5 , and toxicity unit (TU) removal. Based on ANOVA, H2 O2 /COD was found to be significant parameter for COD removal, whereas current, reaction time, and H2 O2 /COD were determined to be significant parameters for BOD5 and TU removal. Optimum conditions (pH value of 3.4, current 3 A, reaction time 33.9 min, and H2 O2 /COD of 1.29) were determined, and predicted removals of COD, BOD5, and TU were found to be 55.1%, 42.5%, and 99.7% and experimental removals were found to be 53.4%, 41.2%, and 99.5%, respectively. TU value of the wastewater decreased from the value of 163-0.815, and BOD5 /COD value increased from the value of 0.32-0.39. The results of the study indicate that EF process is an effective treatment option for COD, BOD5, and especially toxicity removal from medical laboratory wastewater. PRACTITIONER POINTS: Electro-Fenton process was applied medical laboratory wastewater with highly toxic characteristic. Response surface methodology approach using central composite design was employed for modeling. 53.4%, 41.2%, and 99.5% of COD, BOD5, and toxicity removals were achieved under statistically optimized conditions. TU value of the wastewater decreased from the value of 163-0.815. BOD5 /COD value increased from the value of 0.32-0.39.
