Environmental pollution has been a difficult problem in the high development of China economy,especially the water pollution and the water pollution is an important part of it.Whether the sewage can reach the discharge standard is determined by the pollution index of the sewage,among which the most important is the Chemical Oxygen Demand(COD)value of the sewage.The conventional method for COD determination is manual and is based on titration of the samples with a toxic reagent such as potassium perman...