Sulfamethoxazole impact on pollutant removal and microbial community of aerobic granular sludge with filamentous bacteria

In this study, sulfamethoxazole (SMX) was employed to investigate its impact on the process of aerobic granule sludge with filamentous bacteria (FAGS). FAGS has shown great tolerance ability. FAGS in a continuous flow reactor (CFR) could keep stable with 2 mu g/L of SMX addition during long-term operation. The NH4+, chemical oxygen demand (COD), and SMX removal efficiencies kept higher than 80%, 85%, and 80%, respectively. Both adsorption and biodegradation play important roles in SMX removal for FAGS. The extracellular polymeric substances (EPS) might play important role in SMX removal and FAGS tolerance to SMX. The EPS content increased from 157.84 mg/g VSS to 328.22 mg/g VSS with SMX addition. SMX has slightly affected on micro-organism community. A high abundance of Rhodobacter, Gemmobacter, and Sphaerotilus of FAGS may positively correlate to SMX. The SMX addition has led to the increase in the abundance of the four sulfonamide resistance genes in FAGS.

Automated summary

This study investigated the effect of sulfamethoxazole (SMX) on aerobic granule sludge with filamentous bacteria (FAGS). The FAGS showed high tolerance to SMX, and stable operation was achieved with 2 µg/L of SMX addition. The removal efficiencies of NH4+, COD, and SMX remained above 80%, 85%, and 80% respectively. Both adsorption and biodegradation played important roles in SMX removal, and extracellular polymeric substances (EPS) were found to be involved in SMX removal and FAGS tolerance to SMX. The addition of SMX slightly affected the microorganism community, but increased the abundance of certain bacteria and sulfonamide resistance genes in FAGS.