Study on prediction of COD in a southern sewage river of certain coastal city

This paper focuses on the prediction of Chemical Oxygen Consumption (COD) in a sewage River. Considering environmental hazards of indiscriminate discharge of sewage, the experiment was performed on a sewage river of selected area. COD was measured at selected sampling locations from Aug 2007 to Aug. 2008. We conducted a total of nine samples. During the experiment, the sampling time is basically the same and time intervals of sampling are also consistent, therefore the sampled data (seven samples) can be looked on as a sequence of time. According to the requirements of time series analysis, manipulate the data and test the stationarity of the series. By time series analysis, an ARIMA (1, 0, 2) model is developed. Significant test of model parameters and adaptive testing of the model show that the ARIMA (1, 0, 2) model of COD was significant. Using the data from water quality testing department of the city to test the model. The results indicates that the veracity of the ARIMA model was 84.9%, which meets the precision requirement of the mode1. The model is conducive to the rational utilization of environmental capacity and can provide scientific foundation for general regulation and management of rivers.