The effectiveness of submerged synthetic aquatic vegetation on removal of colloids from flowing water was investigated to explore retention of particulate nonpoint source pollutants in aquatic systems. In colloid transport experiments, the deposition rate coefficient of colloids in dense vegetation is often taken as spatially constant. This assumption was tested by experiments and modeling aimed at quantifying changes in colloid retention with travel distance in submerged synthetic aquatic vegetation. Experiments were performed in a 10-m long, 0.6-m wide flume with a 5-cm water depth under different fluid velocities, initial colloid concentrations, and solution pH values. A model accounting for advection, dispersion and first-order kinetic deposition described the experimental data. The colloid deposition rate coefficient showed a power-law decrease with travel distance, and reached a steady state value before the end of the flume. Measured changes in colloid properties with transport distance (ζ potential and size) could not explain the observed decrease. While gravity was shown to contribute to the decrease, its impact was too weak to explain the decreasing power law trend, suggesting that processes operating in granular media to produce similar outcomes may also apply to submerged vegetation.

研究了淹没的合成水生植被对从流动水中去除胶体的有效性，以探索水生系统中颗粒状非点源污染物的保留。在胶体输运实验中，稠密植被中胶体的沉积率系数常被视为空间常数。该假设通过旨在量化水下合成水生植被中胶体保留随行进距离变化的实验和建模进行了测试。实验是在 10 米长、0.6 米宽、5 厘米水深的水槽中在不同流体速度、初始胶体浓度和溶液 pH 值下进行的。考虑平流、弥散和一级动力学沉积的模型描述了实验数据。胶体沉积速率系数随行进距离呈幂律下降，在水槽结束前达到稳态值。随传输距离（ζ 电位和尺寸）测量的胶体特性变化无法解释观察到的下降。虽然重力被证明有助于减少，但它的影响太弱，无法解释幂律下降的趋势，这表明在颗粒介质中运行以产生类似结果的过程也可能适用于水下植被。