Rural sewage treatment plants are small in scale (usually with a treatment capacity of less than 500 tons/day) and have low influent organic matter concentrations (COD is often less than 150 mg/L), resulting in insufficient carbon sources during microbial denitrification, which seriously affects the effects of nitrogen removal and phosphorus removal. The traditional manual dosing method has several apparent drawbacks: Operators must estimate the dosage based on experience and use an intermittent dosing mode, which not only results in poor dosing accuracy (with errors reaching ±30%) but also requires a dedicated person to be on duty 24 hours a day. This extensive management results in a carbon source utilization rate of less than 40% and an annual increase in labor costs of approximately 20,000 to 30,000 yuan. What’s more serious is that it is impossible to adjust the dosage in real time according to changes in the influent load, resulting in large fluctuations in the effluent water quality (TN concentration fluctuation range 2-8 mg/L), which not only increases the waste of reagents, but also makes it difficult to stably meet the Class A emission standards, significantly increasing the comprehensive operating costs of village and town sewage treatment.