Impact of dredging on nitrogen release from sediment in seriously polluted river

Based on experiments of nitrogen release using samples taken from the surface,middle,and bottom layers of the sediments of a dredged river under static conditions,the effect of dredging on nitrogen release from layered sediment was examined.The results indicate that the TN release process can be divided into three phases: rapid release,transitional release,and balance release.The more dredging was conducted,the lesser the TN concentration in sediment after dredging,and the greater the reduction of TN release from sediment.However,the nitrogen load in the remaining sediment was still high after dredging of the surface sediment.