Anaerobic biological treatment of methylparaben in an expanded granular sludge bed (EGSB)

This study evaluated the behavior of an anaerobic expanded granular sludge bed system using different methylparaben (MPB) concentrations. The assay was conducted for 268 days and was divided into seven stages of operation, which included the starting stage and subsequent stages where the MPB concentration was increased. The inoculum that was used was a mixture of anaerobic granular sludge with flocculent active sludge that contained 21.7 g/L of total suspended solids and 17.4 g/L of volatile suspended solids, resulting in an organic content of approximately 80%. The MPB removals after applying concentrations of 300 mg/L, 500 mg/L and 1,000 mg/L during the different stages and adding glucose to the influent were 94 ± 2.4%, 84 ± 5.8% and 88 ± 7.4%, respectively. For phases without glucose, the results were 97.4 ± 0.4%, 96 ± 1.6% and 98.2 ± 0.3%, respectively. The results showed a high pollutant removal and good progress in terms of the physical and biological characteristics of the granular biomass, which showed no change in the presence of the compound or a concentration increase.