溶解氧对河流底泥中三氮释放的影响

The effect of DO on nitrogen releasing from sediments of rivers

作为内源污染的底泥沉积物中营养物的释放引起了越来越多的关注。通过大型静态土柱模拟实验,研究氮在上覆水和孔隙水中的分布特性和释放特性。在控制氧气条件、底泥有机质含量和粒径大小的条件下,连续观测氨态氮、亚硝态氮和硝态氮的浓度及其垂向分布特性。结果发现:时间分布上,通氧条件明显影响水体底泥中三氮释放与反硝化作用达到平衡的时间;垂向分布上,三期实验的上覆水的无机氮以氨态氮为主,不同的通氧条件下,各柱的孔隙水的三氮浓度比上覆水高,且三氮在沉积物中随深度增加而增加;氨态氮和硝态氮浓度则以孔隙水的为高,随深度增加而增加;低溶解氧水平加快底泥释放氨氮速度和增大释放量。

Sediments release nutrition has been the focus of. The nitrogen distribution and release to the overlying water and interstitial water through a series of large static simulating experiments were probed into. The concentration profiles and vertical distribution of NH 4 +, NO 2 - and NO 3 - were observed under different dissolved oxygen condition, organic content and grain sizes. The results showed that: variation with time: different DO condition strongly influenced the balance of the nitrification and de\|nitrification; variation with depth: the concentration of NH 4 + and NO 3 - in overlying water were far less than in interstitial water with different DO condition or organic level or grain sizes, and increased with further depth. The concentration of NO 2 - in overlying water is less than in interstitial water with different DO condition but sometimes more than with different organic level or grain sizes. Low concentration DO accelerates the velocity of nitrogen distributing and increases its quantity in the overlying water.