Effect of surfactants on absorption of nitrogen and phosphorus by Spirodela polyrrhiza

Key words: 
• surfactant /
• Spirodela polyrrhiza /
• ammonia nitrogen /
• total phosphorus

Abstract: Effects of anion surfactant LAS,cationic surfactant CTMAB and non-ionic surfactant Tween-80 on the absorption of nitrogen,phosphorus and the growth of the plant by Spirodela polyrrhiza were studied by several test indices:ammonia nitrogen,total phosphorus and biomass increase,using indoor cultivation methods.The results showed that Spirodela polyrrhiza grew well in a simulated eutrophic water without surfactants，showing a very strong ability to remove nitrogen and phosphorus;when concentrations of LAS and CTMAB were lower than 1 mg/L，the absorption of total phosphorus by Spirodela polyrrhiza was more susceptible than that of nitrogen;when the concentration reached to 10 mg/L,Spirodela polyrrhiza was obviously damaged by the presence of LAS and CTMAB,showing a negative absorption rate of nitrogen and phosphorus.The toxicity of non-ionic surfactant was relatively the smallest and its influence on absorption of nitrogen and phosphorus by Spirodela polyrrhiza was significantly lower than anionic surfactant and cationic surfactant.