In situ sediment remediation using modified clay has become increasingly popular in aquatic ecosystem management. In this study, two modified clays, Phoslock® and modified zeolite, were used together to co-manage nitrogen and phosphorus loading from a polluted river sediment and intermittent aeration was used as an aid for this remediation. After 120 days of core incubation, results indicated that the two clays alone cannot effectively control all the total and soluble nitrogen and phosphorus concentrations in the overlying water all the time. However, the combined use of clays with intermittent aeration can effectively reduce the nutrient concentrations throughout the experiment. Sediment phosphate flux can be largely inhibited solely by clays or when combined with aeration. Meanwhile, the ammonium flux can only be inhibited effectively for 60 days and is not statically different from control after 120 days. Surprisingly, intensive bioturbation can create a vertical movement of the applied clays in sediment with time, which enhances the phosphorus and nitrogen retention capacity of the subsurface sediment. Phosphorus fractionation analysis indicated that around 50% of mobile phosphorus was reduced in a 4–6 cm sediment layer after 120 days. In contrast, the extractable ammonium and nitrate content in treated sediment increased 2–3 times in this layer. The short-term bioturbation experiment confirmed that bioturbation did not have a large effect on P control efficiency of the clay-treated sediment. Conversely, bioturbation can enhance ammonium release from sediment and the following gradual burial effect can have a negative effect on nitrogen removal from overlying water over time. These results indicate that intensive bioturbation should be considered in polluted river sediment remediation.

在水生生态系统管理中，使用改性粘土进行原位沉积物修复已变得越来越普遍。在这项研究中，两种改性粘土（Phoslock®和改性沸石）一起用于共同管理受污染河流沉积物中的氮和磷负荷，并采用间歇通气作为补救措施。岩心温育120天后，结果表明，单独使用两种黏土并不能始终有效地控制上覆水中所有总氮和可溶性氮和磷的浓度。但是，在间歇性曝气中结合使用粘土可以有效降低整个实验过程中的养分含量。泥沙或与曝气结合时可大大抑制沉积物中的磷酸盐通量。同时，铵通量仅能有效抑制60天，并且在120天后与对照无静态差异。出人意料的是，强烈的生物扰动可以使沉积物中的黏土随时间垂直移动，从而增强了地下沉积物中磷和氮的保留能力。磷分级分析表明，120天后4-6 cm的沉积物中约有50％的可移动磷减少了。相反，在这一层中，处理过的沉积物中可提取的铵和硝酸盐含量增加了2-3倍。短期生物扰动实验证实，生物扰动对粘土处理过的沉积物的磷控制效率没有很大影响。反过来，生物扰动可以增强铵盐从沉积物中的释放，并且随着时间的推移，随后的逐渐掩埋效应可能会对上覆水中的氮去除产生负面影响。这些结果表明，在污染的河流沉积物修复中应考虑进行强烈的生物扰动。