Hospital wastewater treatment using integrated sono-photo-fenton process: Experimental design through RSM

• pH is considered as one of the key variable that can directly affect the performance. • COD and phosphate removal percentages were 94.5% and 99.15% by US/UV/Fe 2+ /H 2 O 2 . • Final COD-11.275mg/L and phosphate - 0.05mg/L were below the environmental limits. • US and UV leads to synergistic effect on more generations of hydroxyl radicals. The present study investigates the degradation capacity of hospital wastewater removal (chemical oxygen demand and phosphate) percentage using a hybrid process of sono-photo-Fenton ( US/UV/Fenton) and evaluating the influence of reaction time, pH, hydrogen per oxide (H 2 O 2 ), initial chemical oxygen demand (COD) and phosphate concentration, and discussed statistical models. This study examines the effect of four independent factors and their interactions on process response using a second order-polynomial model and a statistical experiment design with 48 runs for each experiment. The significance of (P < 0.0001) indicates the significance of the model and the interaction of variables on the response performance of COD and phosphate removal. The significance of the quadratic model equation was performed using value of R 2 = 0.9988 and R 2 = 0.9998 for COD and phosphate removal. The results showed a maximum removal percentage of 94.5% for COD and 99.15% for phosphate at a similar pH-9, reaction time-50 min, H 2 O 2 -20 mg/L , and an initial COD concentration of -205 mg/L and phosphate concentration of -3.45 mg/L. In both experiments, pH is an important factor among the four independent factors (pH, time, H 2 O 2 , initial COD and phosphate concentration), which has the potential to directly impact the removal of COD and phosphate. On the other hand, compared to the initial COD, a superior elimination ratio was at low H 2 O 2 (10 mg/L). The US/UV/Fenton process reduces the amount of ferrous ions exist in the treated water. The US/UV/Fenton process has generally produced encouraging outcomes, and as a result, regarded as a viable treatment method for hospital wastewater.