Determination of the efficiency of Lemna gibba L. on removal of tetracycline and degradation products

In this study, the removal efficiency by Lemna gibba L. of tetracycline and degradation products which have common usage area and a wide half life, seen in urea and extrecta was determined. This study was maintained at two stages which include laboratory and field study. According to the results obtained from study done at laboratory conditions, it was determined that the best removal in TC, ETC, EATC and ATC solutions which prepared at concentrations of 50, 100 and 300 µg/L was maintained for TC at concentration of 50 and 100 µg/L, and for ETC at concentration of 300 µg/L at the end of 10 days hydraulic retention time. It was observed that the best accumulation in 50 µg/L concentration was for EATC and the best accumulation in the body of Lemna gibba L. plant in 100 and 300 µg/L concentration was for TC. According to the results obtained from pilot scale studies, it was determined that the highest TC, ETC, EATC and ATC removal efficiencies of EMWWTP were 79.65+4.0%; 64.42+2.7% and 80.19+2.1%, respectively. The highest TC, ETC, EATC and ATC ATC removal efficiencies of the planted reactor were obtained as 55.42+3.1%; 89.85+1.9%; 39.31+4.4% and 63.42+2.7%, respectively when the effluents of EMWWTP were given to the planted reactor. Any removal was not obtained in the control reactor. Kinetics and isotherm studies were done in TC, ETC, EATC and ATC solutions which prepared at concentrations of 50, 100 and 300 µg/L and it was determined that the best isotherm was fitted to Langmuir isotherm. According to the result of the study, second order kinetics was obtained for TC50, TC100, TC300, ETC50, ETC100, ETC300 and EATC100 concentrations, pseudo first order kinetics was obtained for EATC50, EATC300, ATC50, ATC100 and ATC300 concentrations. According to the results obtained from experimental studies, the highest correlation between TC and degradation products and SS, BOD5, COD and TOC was for ETC, the highest correlation between TC and degradation products and O-PO4-3 and NH4+-N was for EATC, the highest correlation between TC and degradation products and NO2--N was for ATC. It was determined that the best relationship between removal efficiencies of TC and degradation products and removal efficiencies of physicochemical parameters was between NO2--N and ATC. As a result, it was seen that Lemna gibba L. in the pilot scale reactor which the effluents of EMWWTP were given was efficient in the removal of tetracycline and degradation products. It was determined that tetracycline and degradation products which exist in effluents of EMWWTP were accumulated by Lemna gibba L. It was determined by this study that Lemna gibba L. plant could be used as advanced treatment method in treatment of EMWWTP effluents.