Effects Of Tetracycline On The Growth Of Dunaliella Salina,Pavlovia Viridis And Yeast And Their Purification Ability Of Mariculture Wastewater

In this thesis,Dunaliella salina,Pavlova viridis and yeast₂were used as research materials to explore the sensitivity of Dunaliella salina and Pavlova viridis to tetracycline,the purification effect of immobilized two kinds of algae on mariculture wastewater,the lipid content after wastewater treatment,and the purification effect of yeast₂and co-immobilization with two kinds of algae on mariculture wastewater.The results showed that:With the increase of tetracycline concentration,Dunaliella salina and Pavlova viridis were inhibited.When the tetracycline concentration was greater than or equal to 40mg/L,Pavlova viridis was slightly more tolerant to tetracycline than Dunaliella salina.In the purification of mariculture wastewater by immobilized two kinds of algae,the removal rates of COD,ammonia-nitrogen,onorthophosphate-phosphorus and tetracycline by Dunaliella salina were 90.32%,80.43%,74.92%and 77.87%respectively when the cell density was 2.5 million/alginate bead.When the reactor density was 100 alginate beads/100m L,the removal rates of COD,ammonia-nitrogen,onorthophosphate-phosphorus and tetracycline were 71.51%,63.43%,79.09%and 65.47%respectively.The removal rates of COD,ammonia-nitrogen,onorthophosphate-phosphorus and tetracycline by Pavlovia viridis were 81.72%,74.84%,58.09%and 86.48%respectively when the cell density was1.25 million/alginate bead.The removal rates of COD,ammonia-nitrogen,onorthophosphate-phosphorus and tetracycline were 77.96%,58.74%,85.98%and 78.23%respectively when the reactor density was 100 alginate beads/100m L.The lipid contents of the harvested Dunaliella salina and Pavlova viridis were above 16.3%and 20.7%（dry weight）,respectively.In the study of purification of mariculture wastewater by immobilized yeast₂,when the reactor density was 150 alginate beads/100m L,the removal rates of COD,ammonia-nitrogen,onorthophosphate-phosphorus and tetracycline were 83.85%,78.57%,76.93%and 71.12%respectively.In the experiments of different initial ammonia-nitrogen and COD,under the conditions of ammonia-nitrogen concentration of 50mg/L and COD concentration of500mg/L,the removal effect of immobilized yeast₂on mariculture wastewater was better.In the experiment,the maximum removal amount of ammonia-nitrogen and COD was 39.65mg and 638.48mg respectively.In the experiment of co-immobilization of bacteria and algae,when the ratio of yeast₂and Dunaliella salina co-immobilized bacteria alginate beads was 2:1,the removal effect of ammonia-nitrogen was better,and the removal rate was 81.17%;The removal efficiency of tetracycline was better when the ratio of bacterial alginate beads was 1:3,and the removal rate was 84.04%;When the ratio of alginate beads was 100:0 and 0:100,the removal effects of COD and onorthophosphate-phosphorus were better,and the removal rates were 77.42%and77.88%respectively.In the co-immobilization experiment of yeast₂and Pavlova viridis,the proportion of alginate beads with good removal effects on COD and ammonia-nitrogen was100:0,and the removal rates were 77.42%and 81.82%respectively.The proportion of alginate beads with good removal effects on onorthophosphate-phosphorus and tetracycline was 0:100,and the removal rates were 82.75%and 88.62%respectively.