The study used a computer model to see how sewage treatment plant effluent affects the water quality of Zhangze Reservoir. They found that direct inflow of untreated effluent from the plant can harm the water quality. However, treating the effluent through constructed wetlands can improve the water quality, though some pollutants may still be too high. If all rivers entering the reservoir meet standards and the plant's effluent doesn't enter, the water quality can meet standards for some pollutants, but reducing others may be challenging in the short term.