Treatment of phenolic compounds in wastewater by Fenton reaction together with CaO coagulation

A treatment of phenolic compound with fenton reaction together with coagulation by calcium oxide was investigated in this study. COD and residual substances were monitored throughout the work. Phenol and 2,4-Dichlorophenol were selected to represent different kinds of the compound. The weight ratio of fenton reagent or Iron ion: Hydrogen peroxide: CaO was 1:11.7: 4.5, whereas the concentrations of phenolic compound were 1100 and 550 ppm. In case of 1100 ppm, the weight ratio of phenolic compound: Iron ion was 1: 0.65 and in the case of 550 ppm, the weight ratio of phenolic compound: Iron ion was 1: 0.45. The results of the treatment were as follows: percent reduction of CODs of phenol solutions was more than the reduction of 2,4-Dichlorophenol solutions (99% and 85% of 1100 ppm and 97% and 93% of 550 ppm). Comparison of the amount of sulfate in solution and in sediment revealed that, with both phenol and 2,4- Dichlorophenol solutions, the percent of sulfate in the solution was greater than the percent in the sediment (86% and 69% for phenol and 2,4 Dichlorophenol of 1100 ppm) and (93% and 76% for phenol and 2,4 Dichlorophenol of 550 ppm). Comparison of the amount of calcium in solution and in sediment showed that, with both phenol and 2,4-Dichlorophenol solutions, the percent of calcium in the solution was lower than the percent in the sediment (38% and 54% for phenol and 2,4-Dichlorophenol of 1100 ppm) and (48% and 59% for phenol and 2,4-Dichlorophenol of 550 ppm). Almost 100% of Iron residual in the solution was formed in sediments for all cases.