原位生物技术对城市重污染河道底泥的治理效果

以扬州市典型城市内河河道为例研究了人工曝气、生态砖覆盖、生物填料覆盖、低位植物浮床(简称低位浮床)等原位生态处理技术对河道底泥污染释放及其对上覆水污染负荷贡献的治理效果.研究结果表明:经不同原位生态处理后,1)底泥中氨氮的释放速率下降50.3％-89.64％,平均为59.27％；底泥污染释放对上覆水氨氮负荷贡献量的去除率为36.59％-82.67％,平均为53.33％；2)底泥中总氮的释放速率下降20.96％-88.94％,平均为42.32％；底泥总氮释放对上覆水污染负荷贡献量的污染去除率为38.00％-67.06％,平均为54.96％；3)底泥中总磷的释放速率下降27.49％-91.00％,平均为55.31％；底泥总磷释放对上覆水总磷污染负荷贡献量的去除率为67.14％-98.46％,平均为84.33％；4)底泥中CODMn的释放速率下降11.84％-79.32％,平均为41.16％；底泥上覆水中CODMn的释放速率下降-1.25％--70.74％,平均为29.83％.研究还发现,原位生态处理技术在运行中对底泥污染治理的效果受该技术对底泥的扰动程度的影响,在进行集成应用的时候,对底泥扰动较大的技术应与对底泥扰动较小的技术相间应用,以减少工程技术运行中对底泥扰动造成的污染爆发式释放,达到更好的整体处理效果.

A case study of the effects of in-situ bioremediation on the release of pollutants from contaminated sediments in a typical, polluted urban river

A case study of the Yangzhuang River in Yangzhou City, China, was undertaken as an example of a typical, polluted urban river. Emphasis was placed on studying the effects of in-situ bioremediation technologies, such as aeration, eco-brick cover, biological packing cover, and low-sited plant beds on the subsequent release of pollutants from contaminated sediments in the river. Additionally, the amounts of ammonia nitrogen (NH₃-N), total nitrogen (TN), total phosphorus (TP) and COD_Mn released from the sediments were measured, and their contributions to overlying water were individually quantified. The results showed that: 1) NH₃-N release rate of polluted sediment was reduced by 50.30%-89.64%, with an average of 59.27%, and NH₃-N input to the overlying water was reduced by 36.59%-82.67%, with an average of 53.33%; 2) TN release rate showed a decrease of 20.96%-88.94%, with an average of 42.32% and the changes in TN contributions to the overlying water indicated a removal efficiency of 38.00%-67.06%, with an average of 54.96%; 3) the release rate of TP from the sediment was decreased by 27.49%-91.00%, with an average of 55.31%, and TP released to the overlying water displayed a removal efficiency of 67.14%-98.46%,with an average of 84.33%; 4) a decrease of 11.84%-79.32% (41.16% on average) of the release rate of COD_Mn from the sediment and a decrease of -1.25% to70.74%, with an average of 29.83% of the input of COD_Mn to overlying water was indicated. We also found that the effects of in-situ biological technology, with respect to the control of pollutant release from sediment, were affected by the extent of sediment disturbance during their normal operation. For integrated applications, technologies responsible for strong sediment disturbance should be coupled with technologies leading to small sediment disturbance in order to minimize any explosive release of pollutants and thus achieve a superior overall treatment effect.