The Significance of Implementing an Online Monitoring System for Drainage Networks

　　Nowadays in China Online Monitoring of Drainage Networks The volume of system usage continues to rise, primarily because, with the ongoing development of industry and the rapid growth of urban populations, the discharge of industrial wastewater and municipal sewage has increased significantly. Today, China has become one of the countries with the highest and fastest-growing volumes of wastewater discharge worldwide. Overall, China’s wastewater treatment capacity remains relatively low. A substantial portion of untreated wastewater is discharged directly or indirectly, and some large polluting entities even engage in clandestine discharges and leaks, severely contaminating natural water bodies and the ecological environment, thereby imposing grave adverse impacts on people’s quality of life and health.

　　Strengthening online monitoring of sewage and wastewater discharge networks is a critical issue in addressing environmental challenges. Developing appropriate methods for sewage monitoring is key to resolving this problem. China’s Law on the Prevention and Control of Water Pollution stipulates that discharging entities must install online monitoring equipment for water pollutant discharge networks and connect it to the monitoring systems of the competent environmental protection authorities, ensuring the proper operation of such equipment. Enterprises that discharge industrial wastewater are required to monitor their effluents and maintain original monitoring records.

　　As urbanization accelerates, major cities frequently experience urban flooding. During the rainy season, these areas are often inundated by floodwaters. To address urban flooding, it is essential to conduct real-time online monitoring of flow rates, water levels, and other relevant parameters in the city’s drainage network, providing decision‑making data for flood‑control command centers and reliable data support for the engineering survey and design phases of municipal infrastructure projects.

　　At present, in urban drainage network online monitoring systems, the measurement of flow velocity, water level, and flow rate is of paramount importance. Many sewer networks are underground and sealed, making direct measurement challenging. Conventional electromagnetic flowmeters and clamp-on ultrasonic flowmeters are suitable only for fully filled pipes. Municipal stormwater and wastewater networks are generally non-pressure systems, operating under gravity. Consequently, how to monitor municipal drainage pipelines—stormwater pipes, sewage pipes, and combined stormwater–sewage pipes—remains a critical issue. Currently, the most widely adopted solution is an online drainage network monitoring system, which can determine whether a pipe has reached full capacity.

　　 Online Monitoring of Drainage Networks The system measures the Doppler effect caused by scattering of ultrasonic waves from suspended particles as they propagate through water. It is a measurement device that calculates flow velocity by determining the frequency difference between the transmitted and received signals, while simultaneously measuring water level with a pressure sensor and employing the “velocity‑area method” to quantify discharge. This system enables real-time monitoring of wastewater discharge and can automatically adjust its operational status in response to changes in flow rate, thereby achieving optimal performance.