浅水型水库活性区沉积物氮磷释放特征

为了了解浅型水库活性反应区底泥中氮磷的释放特征,对某小型水库活性区0-30cm沉积物柱芯分层进行氮、磷快速释放试验研究。研究结果表明:在厌氧条件下,可溶性无机磷(PO4-P)的释放速率显著比好氧状态下的高,最大释放速率为75.52μg/(h·g);在不同沉积深度的垂直剖面上,PO4-P释放量由大至小依次为中层(ML,14～16cm)、表层(SL,0～2cm)和底层(BL,28～30cm),较高的水温环境可促进可溶性磷释放;水库沉积物聚集了大量NH4-N在好氧条件下,沉积物释放的NH4-N质量浓度逐渐降低,同时伴随着NO3-N质量浓度大幅度增加;在厌氧条件下,NO3-N和NO2-N质量浓度无明显变化;不同沉积深度底泥层硝化作用存在显著差异,表层沉积底泥NO3-N转化速度最大;可通过曝气措施削减水库水中氮磷含量,抑制藻类过度繁殖,进而改善水库水环境质量和出水水质。

Release characteristics of nitrogen and phosphorus by sediment of activated zone in shallow reservoirs

In order to understand the release characteristics of nitrogen and phosphorus by sediment of activated zone in the shallow reservoir,sediment layers sliced from 0-30 cm sediment core of a small and shallow reservoir were analyzed with rapid release experiment.The results show that release rates of dissolved inorganic phosphorus (PO4-P) under anaerobic condition are significantly higher than that of aerobic condition.The maximum rate is 75.52 μg/(h·g).The release concentrations of PO4-P from large to small are middle layer(14-16 cm),surface layer (0-2 cm) and bottom layer (28-30 cm).Higher temperature environment can promote the release of dissolved phosphorus.Reservoir sediment gathers a lot of NH4-N.The release concentration of NH4-N decreases under aerobic condition accompanying remarkabe increase of NO3-N.The concentrations of NO3-N and NO2-N have no significant change under anaerobic condition.Nitrification is significantly different for different sediment layers,in which the surface sediment layer has the maximum conversion rate of NO3-N.Based on the factors affecting the formation of activated zone,some engineering measures such as aerating are recommended to inhibit the excessive multiplication of algae in the water and improve the water quality of the reservoir.