Treatment of real sodium saccharin wastewater using multistage contact oxidation reactor and microbial community analysis.

In this study, multistage contact oxidation reactor (MCOR) with a novel carrier was used for treatment of high-strength sodium saccharin wastewater (SSW) under stepwise increasing salinities from 1.0% to 8.0%. The results revealed that MCOR could effectively remove the organic pollutants from SSW when influent salinity was no more than 4.5%; the chemical oxygen demand (COD) and NH-N removal efficiency under the optimal operating parameters ranged up to 91.5% and 92.7%, respectively. Microbial diversity analysis illustrated that the dominant microbes in SSW treatment system were substantially distinct at different salinities. Pseudomonas was predominant at salinity of 3.5%, while Marinobacterium (a species involved in COD removal) was enriched to a greater degree at salinity of 7.0%. CCA suggested that salinity was the main factor for dynamic evolutions of microbial community structures. This work demonstrated that MCOR is an appropriate method for the treatment of high-strength, high-salinity SSW.