【摘要】 湿地植物分解释放的有机物、氮和磷等会影响人工湿地对水体污染物的去除效率和出水水质.本研究采用尼龙分解袋法研究绿狐尾藻在水中的分解过程及氮磷释放特征.连续60 d的室内分解实验结果表明,前期（0～4 d）绿狐尾藻干物质质量损失速率快,占初始质量的30%,中后期（4～60 d）损失速率减慢,占31%.拟合的一级动力学分解速率常数为0. 014 2d-1,降解50%的干物质需48. 8 d.水体p H值变化情况:0～4 d从7. 60迅速下降到5. 63;中期趋于稳定;后期p H值回升到7. 03,与空白对照值接近.绿狐尾藻分解实验系统中溶解氧浓度从6. 30 mg·L^-1在1 d内快速下降到0. 61 mg·L^-1,表明该系统一直处于厌氧状态.水中总氮浓度0～2 h迅速增加达到12. 7 mg·L^-1,2 h～32 d逐渐降低到5. 80 mg·L^-1,后期略有增加;总磷浓度初期快速升高到18. 4 mg·L^-1,中后期趋于稳定.有机氮（占总氮65. 7%～94. 7%）和无机磷（占总磷61%～89%）是主要的氮磷存在形态.绿狐尾藻体内总氮含量随分解时间逐渐增加,从24. 3 mg·g^-1上升到60. 5 mg·g^-1;而总磷含量从6. 09 mg·g^-1下降到2. 94 mg·g^-1后波动稳定,这可能与附着微生物对氮的吸收和固定等因素有关.本研究证实绿狐尾藻分解过程释放的氮磷营养元素会引起水体二次污染,为此采用合理的植物收割管理措施非常必要.更多还原

【Abstract】 Decomposition of wetland plants could release pollutants,which may affect the removal efficiency and effluent quality of constructed wetlands. The experimental decomposition test of Myriophyllum aquaticum was carried out for 60 d using nylon bags,and release characteristics of nitrogen and phosphorus during the decomposition process were studied. The results showed that the decomposition rate of M. aquaticum was fastest during the first 0-4 d,with a weight loss of 30%,while the degradation rate slowed gradually during the period 4-60 d,with weight loss of 31%. The fitting first-order kinetic decomposition rate constant was 0. 014 2 d-1,and the calculated time to degrade 50% of dry matter was 48. 8 d. The water p H decreased rapidly from 7. 60 to 5. 63 during 0-4 d,stabilized during 4-32 d,and finally increased to 7. 03（ which was close to the control sample without M. aquaticum）. The dissolved oxygen concentration decreased rapidly from 6. 30 mg·L^-1 to 0. 61 mg·L^-1 during 0-4 d,and remained in an anaerobic state. The total nitrogen concentration in the water increased rapidly to 12. 7 mg·L^-1 within 2 h,gradually decreased to 5. 80 mg·L^-1 during 2 h-32 d,and then finally increased slightly. The phosphorus concentration increased rapidly to 18. 4 mg·L^-1 at the beginning of the experiment,and then gradually stabilized. The main forms of nitrogen and phosphorus released by M. aquaticum were organic nitrogen（ accounting for 65. 7%-94. 7% of total nitrogen） and inorganic phosphorus（ accounting for 61%-89% of total phosphorus）,respectively. The total nitrogen content of M. aquaticum increased from 24. 3 mg·g^-1 to 60. 5 mg·g^-1 with increasing degradation time; the total phosphorus decreased initially from 6. 09 mg·g^-1 to 2. 94 mg·g^-1 and then remained constant. These trends may have been related to the fixation of nitrogen by attached microorganisms. Therefore,suitable harvesting and management strategies should be adopted for wetland plants to reduce secondary pollution.更多还原