The persulfate oxidation process, followed by biological treatment, is a hybrid process for the treatment of wastewater containing Rhodamine-B dye.

Abstract

This study investigated a combined approach of a persulfate-based advanced oxidation process followed by biological treatment of a textile industrial effluent. The effluent from the textile industry is primarily composed of various dyes in varying concentrations, resulting in high chemical oxygen demand (COD) and biological oxygen demand (BOD). The model pollutant Rhodamine-Blue was used in the optimization studies (RhB). During the persulfate oxidation process, persulfate activation is required to generate sulfate radicals (SO4−•). Raw laterite soil was used as an external catalyst for the treatment of RhB in batch studies, and it was able to reduce the dye concentration by about 20% in 60 minutes of operation, with initial RhB concentrations of 150 mg L-1 and Persulfate concentrations of 200 mg L-1. Furthermore, alkali-treated laterite soil was used as a catalyst, achieving 57 to 60% removal in 60 min at pH 3 and nearly complete removal after 72 hours of biological treatment. Furthermore, the optimized conditions were tested on real field waters to determine efficiency, and it was discovered that the persulfate oxidation process removed approximately 45% of COD, with further biological treatment for 72 hours increasing the removal efficiency to 64%. All other parameters of water quality were reduced by more than 60%.