不同覆盖材料对沉积物P、N释放的抑制效果

Effect of various inactivation agents on phosphorus and nitrogen release from sediments

以百花湖沉积物为实验对象,选取沸石、粘土、生物炭、褐铁矿和高岭土等5种覆盖材料开展模拟柱静态实验,研究上覆水中总氮(TN)、总磷(TP)和氨氮变化规律。在静态模拟柱90 d实验过程中,第45天时上覆水中TN、氨氮浓度最高,分别为8.79和6.10 mg/L。第45天时氨氮浓度最低的是生物炭组,为1.62 mg/L,第45天时TN浓度最低的是粘土组,为1.92 mg/L。第45天后上覆水TN、氨氮浓度下降,实验结束时生物炭组TN和氨氮浓度均最低,其浓度分别为0.74和0.42 mg/L。实验过程中TP浓度不断上升,到实验结束时空白组TP浓度0.42 mg/L,高岭土组TP浓度最低为0.027mg/L。百花湖水质主要超标指标为TP,而高岭土覆盖对沉积物中P释放的抑制优于其他4种材料,且在百花湖地区易获得、无污染,故建议以高岭土为百花湖原位覆盖材料。

Five cover materials( zeolite,clay,biochar,limonite and kaolin) were selected to comparatively assess different materials inhibitory effect on P and N releasing from sediment of Baihua Lake in the study. The experiment by using a set of columns to observe the variation of TN,TP,ammonia nitrogen of the overlying water in columns was made. The experiment lasted 90 days. The results indicated that the concentration of TN and ammonia nitrogen is highest on the 45 th day,and they are 8. 79 mg / L,6. 10 mg / L,respectively in the blank group. On the 45 th day,the lowest concentrations of TN and ammonia nitrogen were the group of clay( 1. 92 mg / L) and biochar(1. 62 mg / L). In the end of experiment,the lowest concentrations of TN and ammonia nitrogen were the group of biochar,and the concentrations of TN and ammonia nitrogen were 0. 74 mg / L and 0. 42 mg / L. The concentration of TP was rising continually in the whole process of the experiment. In the end of experiment,the concentrations of TP were 0. 42 mg / L and 0. 027 mg / L in the blank and kaolin group respectively and kaolin group was the lowest. TP is the main index exceed the standard in Baihua Lake. The effect of kaolin is better than other four materials on inhibiting the P and N release from the sediment,it is easy to get and no pollution. So kaolin is most suitable for in situ covering at Baihua Lake.