流速对雨水管道中沉积物-水界面磷的释放及其释放速率的影响

The influence of flow rate on the amount and rate of phosphorus release at the sediment-water interface of rainwater pipes

通过实验室模拟研究了进水流速对雨水管道中沉积物-水界面间磷释放规律的影响,得出不同流速条件下沉积物-水界面磷交换的平衡时间,拟合出上覆水磷的平均浓度和沉积物中磷最大累积释放量与流速的关系曲线,并采用连续函数计算方法通过现场采样和实验分析进行不同流速下雨水管道沉积物-水界面磷交换速率的研究,最后根据实验得出的交换速率值,以一条雨水管线为例估算了不同进水流速下沉积物中磷释放总量.结果表明,流速的增大会促进沉积物中磷的释放,且上覆水总磷平均浓度及磷释放最大量随流速的增大而呈指数式增长,对应的指数方程分别为y=1.2194e0.5983x和y=0.436e0.7928x.在实验工况下,流速为0.3、0.5、0.7、0.9和1.1 m.s-1对应的磷平均释放速率分别为0.62、1.04、2.51、2.85和4.09 mg.m-.2min-1;对应的磷释放总量的估算值分别为3410.00、5720.00、27610.00、31350.00和61861.25 mg.

The influence of flow rate on the amount and rate of phosphorus release at the sediment-water interface of simulated rainwater pipes was studied.The phosphorus exchange equilibrium time at the sediment-water interface under different flow rates was obtained.The fitting curves of average phosphorus concentration in overlying water and maximum cumulative phosphorus release and velocity in sediment were also obtained.The sediment-water interface phosphorus exchange rates of rainwater pipes under different flow rates were studied by adopting continuous function calculation method based on filed sampling and laboratory simulation.And finally,taking a rainwater pipeline as samples,the total phosphorus amount released from sediment under different flow rates were derived based on the exchange rate values obtained from simulated experiments.The results show that the phosphorus release increases with the flow rate.Average total phosphorus concentration and the maximum phosphorus release amount of the overlying water show exponential increase with the increase of the flow rate.Corresponding exponential equations were y=1.2194e0.5983x and y=0.436e0.7928x,respectively.In the simulated conditions,phosphorus average release controlled at 0.62,1.04,2.51,2.85 and 4.09 mg·m-2·min-1,respectively.And the corresponding estimated values of total phosphorus release were 3410.00,5720.00,27610.00,31350.00 and 61861.25 mg.