Research on variety of plankton community prior and post sediment dredging in Nanhu Lake,Changchun;

Sediment dredging can effectively lower the contents of nutrient,heavy metals and persistent organic pollutants in sediment,but resuspensiou of sedi- ment during dredging will induce the release of pollutants from sediment to the water column.

Results show that the water quality of Nanhu lake in Changchun is significantly improved after sediment dredging from 2000 to 2002,and the indices of water quality in water lily area even reach or approach to the third level of GB3838-2002.

Some approaches to utilize dredged sediment as resource,such as land utilization,producting construction material and fill material and wastewater treatment material,were analysed.

Ferric trichloride and PAM were used to dewater the dredged sediment.

Dredged sediment which is composed of upland soil enriched with nutritive organic matters could be used beneficially as soil amendments or manufactured soil for horticultural use rather than discarded as spoil material.

In consideration of some disadvantages in conventional methods for treatment of dredged sediment, the method of solidification was adopted for treatment of dredged sediment from the seriously polluted water body of the west Wulihu Lake.

In order to minimize the environmental pollution created by the traditional disposal methods of dredged marine sediments,a method was proposed to solidify the dredged sediments for beneficial use.

Pot experiments were conducted to study the physiological and ecological effect of dredged sewage river sediment on horticultural plants — Lolium multiflorum Lam.

This is a part of a subject " study on the sludge disposal and the reclamation in the urban dredged sewage river sediment (serial number of project: 043111811)".