Adsorption behavior of sulfamethazine in an activated sludge process treating swine wastewater

Weiwei Ben , Zhimin Qiang , Xiaowei Yin , Jiuhui Qu , Xun Pan


Received September 13, 2013,Revised April 11, 2014, Accepted , Available online August 28, 2014

Volume 26,2014,Pages 1623-1630

Swine wastewater is an important pollution source of antibiotics entering the aquatic environment. In this work, the adsorption behavior of sulfamethazine (SMN), a commonlyused sulfonamide antibiotic, on activated sludge from a sequencing batch reactor treating swinewastewaterwas investigated. The results showthat the adsorption of SMN on activated sludge was an initially rapid process and reached equilibrium after 6 hr. The removal efficiency of SMN from the water phase increased with an increasing concentration of mixed liquor suspended solids, while the adsorbed concentration of SMN decreased. Solution pH influenced both the speciation of SMN and the surface properties of activated sludge, thus significantly impacting the adsorption process. A linear partition model could give a good fit for the equilibrium concentrations of SMN at the test temperatures (i.e., 10, 20 and 30℃). The partition coefficient (Kd) was determined to be 100.5 L/kg at 20℃, indicating a quite high adsorption capacity for SMN. Thermodynamic analysis revealed that SMN adsorption on activated sludge was an exothermic process. This study could help to clarify the fate and behavior of sulfonamide antibiotics in the activated sludge process and assess consequent environmental risks arising from sludge disposal as well.

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