Pollution Characteristics Investigation And Restoration On Haihe River Sediments

The water pollution is serious in our county. According to the Environment Conditions Bulletin of China in2011, the surface water environmental quality belongs mildly polluted, and the eutrophication issues were outstanding. Of all the469monitoring sections in river systems,25.3%of them belong Ⅳ and Ⅴ water quality, and13.7%of them below Ⅴ water quality. Specifically, to the rivers flow through urban and industrial areas, the water conditions are more serious. The pollutants might be accumulated in the sediments by precipitation, adsorption, biological uptake and other processes. These sediments might accumulate over long periods and could act as new pollutant sources to the overlying water after the water quality has improved. Thus, controlling the pollutants in sediment is significant for water body restoration.We analyzed the pollutants of surface water and sediments in Haihe River, then selected the main pollutant for restoration experiments. And we discussed the effect of NZVI under different conditions, then determined the best processes and amount.The results show that the N and P pollution were significant in surface water, and most monitoring sections were below Ⅴ water quality. The amount of P in Haihe River sediments were more than other domestic rivers. The HCl-P and Res-P were the main fractions in sediments. The concentration of TDP was much more than TP of surface water, which indicated the P could be easily released from sediments to surface water. The releasing of P was obviously controlled when the NZVI added. The effect of cover group was the best, and the concentration of TP in cover group was about1/10of that in control group. The amounts of P in2%group were about16.3%~33.3%less than that in1%group, and they were similar to4%group. Therefore, it was enough to add2%NZVI in sediments for restoration.