方解石活性覆盖系统抑制底泥磷释放的影响因素研究

通过摇床振荡试验和底泥磷释放控制模拟试验,考察了覆盖系统厚度、上覆水Ca2 浓度、温度、方解石粒径以及人工曝气等对方解石活性覆盖系统抑制底泥磷释放效率的影响.结果表明,方解石覆盖系统可以抑制厌氧状态下底泥磷的释放,且抑制效果受覆盖系统厚度、上覆水Ca2 浓度、温度、方解石粒径及人工曝气等的影响.方解石覆盖系统对底泥磷释放的抑制效率随厚度的增加而明显提高,方解石投加量由12.7 kg/m2增加到38.2 kg/m2,模拟期间覆盖系统对底泥磷释放的抑制率则由56%增加到99%;上覆水的Ca2 会增强方解石覆盖系统对底泥磷释放抑制的效率,上覆水Ca2 浓度由1 mmol/L增加到5mmol/L,模拟期间上覆水的磷浓度下降36%左右;对于方解石投加量较少的情况下,高温条件与低温条件相比,底泥向上覆水释放更多的磷,而通过增加覆盖系统的厚度可以消除高温所带来的不利影响;方解石覆盖系统对底泥磷释放的抑制效率随粒径的减小而明显增强;对方解石覆盖系统表面进行人工曝气,不仅可以降低底泥氨氮的释放速率,而且还可以降低底泥磷的释放速率.

Influencing Factors of Calcite Active Barrier System to Control Phosphorus Release from Sediments

Influencing factors of calcite active barrier system to control phosphorus release from sediments were researched,including barrier thickness,Ca~(2 ) of overlying water,temperature,calcite's grain size and artificial aeration.The results show that the calcite barrier can effectively control phosphorus release from sediments under anaerobic conditions,and its efficiency was influenced by barrier thickness,Ca~(2 ) concentration of overlying water,temperature,calcite's grain size and artificial aeration.The efficiency of calcite barrier to control phosphorus release from sediments will increase with the increment of Ca~(2 ) concentration of overlying water and barrier thickness.Application of 12.7(kg/m~2) calcite active barrier system resulted in 56% reduction of phosphorus flux from sediment for 72 days;however 99% reduction was obtained by 38.2(kg/m~2) calcite active barrier system.When the Ca~(2 ) concentration of overlying water increased from 1 (mmol/L) to 5 (mmol/L),the phosphorus concentration was reduced by about 36% in the 72~(th) day.In comparison to low temperature,high temperature was disbennifit to control phosphorus release from sediments by a thin calcite barrier.The smaller the grain sizes of calcite,the more efficient the calcite barrier.The ammonia and phosphorus release rate from sediments under calcite barrier will be decreased by aeration.