Effects of chemical agents on the overlying water during in-situ sediment treatment

The zero valent iron(Fe⁰) or calcium nitrate was added into the sediment of Suzhou creck for 80 days in the anaer obic environment for in-situ sediment treatment.The effects of chemical agents on the overlying water were studied by DO,pH,Eh,COD_Cr and TOC measurements.The results show that DO is depleted dramatically by Fe⁰ added,resulting in anaero bic environment easily,whereas the consumption of DO is delayed by the added calcium nitrate.And Fe⁰ or calcium nitrate added will raise pH value and descend Eh value.Meanwhile,the effect on COD_Cr or TOC in overlying water by Fe⁰ added is lower than that of the calcium nitrate added.In addition,there are certain relations among DO,pH and Eh or between COD_Cr and TOC in overlying water as Fe⁰ or calcium nitrate is added respectively.