再力花/菖蒲生物湿地床去除河水中氮磷的试验

摘要

Nitrogen and phosphorus removal were studied in the bio-rack systems with Thalia dealbata and Acorus calamus Linn for purifying river water. The results showed the survived rates of two plants were more than 93%, when Hydraulic loading was controlled at 0.24 mV( m2 · d) and plants density was more than 158 plants/m2. This indicated that the plants could be adaptable Under the condition of lower pollution and higher plant density. Total nitrogen(TN) average removal rates per month were 48. 22% -78. 53% and 43. 23% -72.42%, total phosphorus (TP) average removal rates per month were 77.62% -85.67% and 58.07% -80.77% in the bio-rack wetland planted with Thalia dealbata and Acorus calamus Linn respectively. The removal rates for N and P were higher in the bio-rack wetland planted with Thalia dealbata than wetland planted with Acorus calamus Linn. Nitrogen uptake by plants accounted for 44. 14% , 41. 08% in the Thalia dealbata and Acorus calamus Linn systems, while for P, the removal ratio was 73.43% , 62.05% respectively. It indicated that the bio-rack wetland was an efficient way for purifying river water, the contribution rate on N, P removal of plants assimilation was obvious, and different plants species had significantly difference for the bio-rack wetland removing N and P of river water. The study also showed that nitrification/denitrification process and plant uptake process are major removal pathways for TN, while plant uptake is an effective removal pathway for TP.%采用再力花和菖蒲构建湿地床,以考察其对污染河水的净化效果.6个月的连续试验表明:在水力负荷为0.24 m3/(m2·d)、植物种植密度大于158株/m2的条件下,2种植物存活率均大于93％,说明植物能适应低污染负荷、高种植密度的无土培养环境；再力花和菖蒲湿地床月均去除率分别为:总氮(TN),48.22％ ～78.53％和43.23％～72.42％；总磷(TP),77.62％～85.67％和58.07％～ 80.77％.再力花湿地床对TN、TP的净化效果好于菖蒲湿地床；2种植物吸收N、P含量分别占去除总量的比例:N为44.14％、37.75％,P为73.43％、62.05％.湿地床技术可有效去除来水中的TN、TP,通过植物吸收作用累积N、P含量较高,不同种类的植物构建湿地床对污染河水中N、P去除效果存在显著差异,且硝化反硝化和植物吸收是去除N的主要途径,而植物吸收是去除P的有效手段.