Removal Of Antibiotics In Constructed Wetland And Its Effect On Plant Growth And Sewage Treatment

China is a big country in the production and use of antibiotics.When bringing extensive benefits to people,antibiotics inevitably enter the natural environment,endangering the water environment,soil and other ecological environments.Especially,the antibiotic residue in the water environment is most serious,resulting in the extreme potential risks for the water quality,food safety and human health.The constructed wetland ecosystem has unique advantages in sewage treatment,thus,it has broad prospect in the removal of antibiotics.While,many factors can influence the operation results of constructed wetland,and the wetland plants as an important factor can influence the sewage treatment effect of constructed wetland.In this study,two experiments were performed:(1)Canna,cyperus altrnlifolius,pennisetum hydridum and pontederia cordata as the wetland plants were treated with the water culture experiment,to study the removal effect on antibiotics Amoxicillin(AMX),Florfenicol(FFC)and Doxycycline Hydrochloride(DH),and observe the stress resistance and tolerance.(2)Canna,cyperus altrnlifolius and yellow flag as the wetland plants gravel,river sand,soil and other matrix were treated with the constructed wetland microcosmic experiment,to discuss the removal effect of constructed wetland system on two kinds of antibiotics under different concentrations of FFC and DH,and study the effect of different antibiotics on wetland system in treating the basic water quality index.In this paper,the main conclusions can be divided by experiment and analysis.(1)Under the water culture,the cyperus altrnlifolius,canna,pennisetum hydridum and pontederia cordata had different growth trends and antibiotic removal efficiency under stress of different concentrations of antibiotics.Among four kinds of aquatic plants,under the stress of 10-1000 μg/L amoxicillin,pennisetum hydridum could best remove it,followed by canna and the other two.Under the stress of 100 and 1000 μg/L florfenicol,pennisetum hydridum could best remove it,apparently superior to the other three.Under the stress of 500 μg/L,pontederia cordata could best remove the florfenicol,superior to others.Under the stress of 10-1000 μg/L Doxycycline Hydrochloride,canna could best remove it,while after stressed for 14 d,the plant cyperus altrnlifolius had similar removal effect to the canna,but inferior to the canna.(2)Under the water culture,the removal efficiency of different plants on antibiotic was compared,finding that under the stress of Doxycycline Hydrochloride,canna had highest removal efficiency at 100 μg/L,as high as 55%.Under the stress of florfenicol,pennisetum hydridum had highest removal efficiency at 100 μg/L,as high as 56.2%.Under the stress of amoxicillin,the removal efficiency of pennisetum hydridum was similar to canna,reaching the relative highest value,as high as 53.5% and 54% respectively.(3)In the constructed wetland microcosmic system,under the stress of different concentrations of antibiotics,the wetland system with plants was apparently superior to that without plants in the removal of basic water quality indexes.Among which,the removal efficiency on total nitrogen,ammonia-nitrogen and COD was canna > cyperus altrnlifolius > yellow flag.Under the stress of moderately-concentrated antibiotic,the removal efficiency of three plants on the total phosphorus was basically similar,while under the stress of highly-concentrated antibiotic,the absorption of canna on phosphorus was saturated earliest,while last for the cyperus altrnlifolius.(4)For the constructed wetland system with different plants,its removal effect on antibiotic was mainly dependent on the antibiotic concentration.Under the lowly concentrated antibiotic,the removal effect of three plants was apparently superior to the constructed wetland system in the blank group,the canna wetland system was the best plant-constructed wetland system.Under the constructed wetland system treated with highly-concentrated antibiotic,the yellow flag wetland system could remove the antibiotic same as the constructed wetland system in the blank group,but the canna was apparently superior to other constructed wetland systems in the removal of two antibiotics.Thus,the canna-constructed wetland system is the best constructed wetland system in the removal of antibiotics florfenicol and doxycycline hydrochloride.