A Positional Method for Accidental Chemical Oxygen Demand to Determine a River’s Pollution Source

Abstract

This study stems from a current lack of technology to assess pollutantsources along rivers located in China. A positive water quality distribution model forpollution sources was established, which applies reverse tracing to investigate the likelysource of pollution, and a positional method of accidental chemical oxygen demand(COD, analyzed using the dichromate method GB11914-89, the COD in this papertherefore refers to CODcr) of the pollution source in a river was proposed. This methodis based on the COD degradation principle in a natural water body, where the variationin the concentration of pollutants in the controlling cross sections was calculated byestablishing a mathematical model. A set of calculated values for the controlling crosssections were determined by making educated assumptions about each accidental outlet.The calculated value and the monitored value in the same cross sections were thenmatched, and the outlets with calculated values that were closer to the monitored valueare likely to be the sources of accidental pollution. On this basis, the probability valuesof these matching outlets were calculated by error sequence.