有机物对人工湿地基质除磷影响研究

以页岩陶粒为基质,在水力停留时间2d,连续进出水条件下,研究分析了进出水中磷素、基质中磷的形态和附着生物量的变化情况.结果表明,基质的除磷效率随有机物浓度的增加而降低,有机物对页岩磷吸附能力有一定的抑制作用.当进水COD浓度分别为100mg/和200mg/L时,其吸附能力分别下降了49%和62%.有机态松散结合磷、腐殖质态磷和钙镁结合磷明显提高,而铁铝结合磷从36.75%分别降到18%和11.77%,证明有机物累积对铁铝结合磷形成的抑制是磷吸附能力下降的主要原因.另外,进水有机物浓度越高,反应器中基质附着的生物膜量就越大,生物膜的厚度可能会影响水中磷元素向基质扩散时传质的过程.

Effect of Organic Matter on Phosphorus Removal for Substrate in Constructed Wetland

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.