The researchers studied water quality in the Qinhuai River by dividing the pollution sources into control units. They created a model to calculate the river's capacity to handle pollutants like COD and ammonia. Results show that with sewage interception and water diversion, the river can meet water quality standards in the near future. In the long term, increased sewage interception will further improve water quality. The study also analyzed how pollutants are shared between different parts of the river and sewage pump stations.