Online monitoring system for sewage inlet and outlet water quality

1、 Project background

In urban sewage treatment, the construction of urban sewage treatment facilities has been elevated to a prominent position in urban infrastructure construction, bringing the construction of urban sewage treatment facilities into a new stage of development. However, at present, water quality monitoring of pollution sources and sewage discharge channels in various parts of the country is still in the manual monitoring stage, which is difficult to reflect the continuous changes in sewage discharge from enterprises and cities. In terms of water resource pollution, efforts are constantly being made to strengthen governance. However, due to various factors such as weak environmental protection awareness and the drive of interests, arbitrary discharge of sewage and non-standard discharge often occur, resulting in serious environmental pollution. Therefore, providing an effective, practical, and advanced monitoring system and solution in monitoring and supervision, establishing an online monitoring system for sewage treatment, is extremely urgent. Improving water quality monitoring capabilities is imperative.

2、 Advantages of System Solutions

In sewage treatment monitoring projects, many of the sewage treatment monitoring systems involved require unmanned equipment or monitoring points, which are affected by factors such as terrain, climate, and monitoring range, and are not suitable for data transmission methods such as wired communication and wireless data transmission radio. They also have disadvantages such as poor mobility, high cost, poor scalability, and inconvenient equipment maintenance. However, mobile GPRS networks have a wide coverage, high-speed data transmission, and always online characteristics. Coupled with flexible tariff methods, the application of GPRS communication in sewage treatment monitoring systems has unparalleled cost-effectiveness advantages.

3、 System solution

（1） System composition

This system is a sewage monitoring system composed of sewage discharge monitoring points, monitoring center stations, and management centers. The system can achieve automatic sampling of enterprise wastewater and urban wastewater, online monitoring of flow rate, and online monitoring of major pollution factors; Real time monitoring of enterprise and urban sewage discharge and total pollutant discharge, achieving automatic transmission of monitoring data; The water quality parameters are automatically collected, processed, saved, and transmitted through remote communication by monitoring points. The computer control center of the measurement center station collects, organizes, and comprehensively analyzes the data; The monitoring information is transmitted to the Environmental Protection Bureau, which supervises and manages the enterprise. The system diagram is as follows:

1. Sewage discharge monitoring points

The sewage treatment monitoring point utilizes various sensors or specialized instruments to collect physical and chemical parameters related to sewage treatment. Such as the operation status of sewage treatment equipment, industrial water discharge sewage flow rate, sewage pH value, relative turbidity of sewage, etc. All kinds of data are transmitted from the communication port of the monitoring instrument to the GPRS DTU, which converts the data into TCP/IP packets and sends them to the monitoring center station data center server port with a fixed IP address or domain name set in the GPRS DTU.

2. Monitoring Center Station

The computer system of the monitoring center station mainly consists of a data communication subsystem, a data processing subsystem, and a report system. The main functions completed include data communication, data processing, and report statistical analysis.

The data processing subsystem and report system serve as the main human-computer interaction interfaces, receiving information transmitted from monitoring points and monitoring information from other pollution sources; Responsible for classifying, screening, and comprehensive analysis of monitoring information; Complete data statistics, calculations, and processing, and automatically generate various reports; It has functions such as storage, display, recording, printing, and statistics, and can also send relevant query commands and control information to monitoring points.

After the GPRS DTU of each monitoring point is powered on, it automatically dials to the GPRS network and establishes a TCP link with the pre-set IP address or domain name. This enables bidirectional data transmission between the monitoring center and each monitoring point.

Basic functions and characteristics:

　　◎ Equipped with various interface resources, including analog signal acquisition, switch input and output, pulse signal input, etc; 

　　◎ Support a user data interface with RS232/RS485 mode, which can be connected to various devices such as PLC; 

　　◎ The integration of data collection, transmission and control improves system reliability and reduces costs; 

　　◎ Adopting industrial grade ultra-low power and high-performance embedded processors; 

　　◎ User programmable range conversion and alarm upper and lower limit settings; 

　　◎ Equipped with an industrial clock for precise timing; 

　　◎ Automatic scheduled reporting and event triggered reporting functions; 

　　◎ Built in high-capacity FLASH memory, automatic data recording, and support for historical data retrieval; 

　　◎ The onboard GSM/GPRS transmission module facilitates users to choose GSM and GPRS networking methods; 

　　◎ Provide user settings software with an open interface for easy connection with group software and other software; 

　　◎ Industrial grade design, stable and reliable, sturdy and durable; 

4. Security features

The above methods are implemented through the Internet (CMNET), which reduces the implementation cost for users. If high reliability data transmission is required. China Mobile provides a direct way for this application to access GPRS networks. The data center server connects to GPRS mobile base stations through dedicated lines and obtains a fixed IP address. The monitoring point data does not need to be routed to the Internet network, and the monitoring point DTU also uses a fixed IP address SIM card. Using this method to form a peer-to-peer network has the characteristics of good real-time performance and high security, but the access cost is relatively high.

At the same time, the monitoring center and management center are also networked, and the monitoring information is transmitted to the management center, which supervises and manages the enterprise.