The adsorption efficiency of N and P by in-situ remediation of modified sediment composite material

Dredged sediment can occupy a large amount of land area, resulting in waste of land resources, and high disposal costs. In response to the problem, this work calcinates and modified the sediment and compounds it with the modified water purification plant sludge, zeolite powder, and bentonite. This is used as a covering material to inhibit the release of nitrogen (N) and phosphorus (P) in the sediment. The results showed that sediment modified composite material covering effectively reduces the release of nitrogen (N) and phosphorus (P) in the sediment, especially the release of P. When the thickness of the covering layer is 3 cm, the reduction rate of total N, NH4+-N, and total P in the overlying water by the modified composite material of sediment is 61.58, 79.59, and 70.34%, respectively. It can be seen that the covering material has a significant effect on the control of the release of N and P in the sediment. Additionally, the reduction of nutrients in the overlying water can overcome the negative effects of temperature rise in controlling the release of N and P in the sediment.