| Effect of organic matter(OM) on the phosphorus(P) removal efficiency for shale-haydite in constructed wetland was investigated. At the conditions of hydraulic retention time 2 d, water flew in and out continuously, P concentration in water, its fractions in the substrate, and biomass in biofilm were analyzed. The results showed that the P removal efficiency for the substrates decreased with the increasing concentration of the OM, and that P sorption capacity for the substrate was inhibited by the OM. When COD in the influent were 100 mg/L and 200 mg/L, P sorption capacity was decreased to 49% and 62%, labile organic phosphorus, Humic-P and Ca/Mg-bound P were significantly increased, Fe/Al-bound P was decreased from 36.75% to 18% and 11.77%. Thus, the result indicated that due to the OM accumulation, the portion of Fe/Al-bound P was low, and P sorption capacity was inhibited. In addition, the higher the concentration of OM is, the more biomass in biofilm is. The thickness of biofilm negatively correlated with mass transfer of phosphorus through the biofilm. |
